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Sample records for heterotrophic ampharetid polychaetes

  1. Do ampharetids take sedimented steps between vents and seeps? Phylogeny and habitat-use of Ampharetidae (Annelida, Terebelliformia) in chemosynthesis-based ecosystems.

    Science.gov (United States)

    Eilertsen, Mari H; Kongsrud, Jon A; Alvestad, Tom; Stiller, Josefin; Rouse, Greg W; Rapp, Hans T

    2017-10-31

    A range of higher animal taxa are shared across various chemosynthesis-based ecosystems (CBEs), which demonstrates the evolutionary link between these habitats, but on a global scale the number of species inhabiting multiple CBEs is low. The factors shaping the distributions and habitat specificity of animals within CBEs are poorly understood, but geographic proximity of habitats, depth and substratum have been suggested as important. Biogeographic studies have indicated that intermediate habitats such as sedimented vents play an important part in the diversification of taxa within CBEs, but this has not been assessed in a phylogenetic framework. Ampharetid annelids are one of the most commonly encountered animal groups in CBEs, making them a good model taxon to study the evolution of habitat use in heterotrophic animals. Here we present a review of the habitat use of ampharetid species in CBEs, and a multi-gene phylogeny of Ampharetidae, with increased taxon sampling compared to previous studies. The review of microhabitats showed that many ampharetid species have a wide niche in terms of temperature and substratum. Depth may be limiting some species to a certain habitat, and trophic ecology and/or competition are identified as other potentially relevant factors. The phylogeny revealed that ampharetids have adapted into CBEs at least four times independently, with subsequent diversification, and shifts between ecosystems have happened in each of these clades. Evolutionary transitions are found to occur both from seep to vent and vent to seep, and the results indicate a role of sedimented vents in the transition between bare-rock vents and seeps. The high number of ampharetid species recently described from CBEs, and the putative new species included in the present phylogeny, indicates that there is considerable diversity still to be discovered. This study provides a molecular framework for future studies to build upon and identifies some ecological and

  2. Biotransformation of polycyclic aromatic hydrocarbons in marine polychaetes

    DEFF Research Database (Denmark)

    Jørgensen, Anne; Giessing, Anders; Rasmussen, Lene Juel

    2008-01-01

    Deposit-feeding polychaetes constitute the dominant macrofauna in marine environments that tend to be depositional centers for organic matter and contaminants. Polychaetes are known to accumulate polycyclic aromatic hydrocarbons (PAHs) from both particulate and dissolved phases but less is known...... about the mechanisms underlying elimination of accumulated PAHs. An important pathway of elimination is through biotransformation which results in increased aqueous solubility of the otherwise hydrophobic PAHs. Biotransformation in marine polychaetes proceeds in a two phased process similar to those...... well studied in vertebrates, phase I enzymes belonging to the Cytochrome P450 (CYP) enzyme family, along with a few phase II enzymes have been identified in marine polychaetes. In this review we aim at highlighting advances in the mechanistic understanding of PAH biotransformation in marine polychaetes...

  3. Deep-water polychaetes (Annelida from the southeastern Gulf of California, Mexico

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    Nuria Méndez

    2006-09-01

    Full Text Available Polychaetes inhabiting deep-sea soft bottoms from the southeastern Gulf of California were collected during four oceanographic cruises during 2000 and 2001. Sampling of benthic organisms was performed with a benthic sledge to collect epifauna and a Karling dredge for epifauna and infauna, in a depth range from 732 to 2 250 m. A list of the polychaetes that were collected and their distribution are presented here. A total of 73 species (distributed among 33 families were identified. Moreover, 11 species were identified only to genus level and 20 species only to family level. With the exception of Ancistrosyllis hartmanae and Melinnampharete eoa, all identified species have been previously reported in soft bottoms of the Gulf of California or in adjacent areas. Additional previously unreported information is provided herein regarding depth ranges, geographical distribution, morphology and tubes inhabited by the organisms. The morphology of the ampharetids Amage sp. and Samytha sp. does not coincide with that of other species in these genera reported for the Gulf of California, which suggests that they are probably undescribed species. Rev. Biol. Trop. 54 (3: 773-785. Epub 2006 Sept. 29.Se recolectaron anélidos poliquetos de fondos profundos del SE del golfo de California durante cuatro campañas oceanográficas entre 2000 y 2001. El muestreo de organismos bentónicos se llevó a cabo mediante una draga de arrastre bentónica para recolectar epifauna y una draga tipo Karling para epifauna y endofauna, en un intervalo de profundidad de 732 a 2 250 m. Se presenta un listado de poliquetos con su distribución dentro del área de estudio. En total se identificaron 73 especies (distribuidas en 33 familias. Además, 11 especies fueron identificadas a nivel genérico y 20 a nivel de familia. Con excepción de Ancistrosyllis hartmanae y Melinnampharete eoa, todas las especies habían sido registradas en fondos blandos del golfo de California o zonas

  4. Polychaetes from Aysen Fjord, Chile: distribution, abundance and biogeographical comparison with the shallow soft-bottom polychaete fauna from Antarctica and the Magellan Province

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    J. I. Cañete

    1999-12-01

    Full Text Available This paper analyzes the composition, abundance and biogeographical relationship of the benthic polychaetes collected in three shallow subtidal locations (mouth of Cuervo and Condor rivers and Acantilada Bay from Aysen Fjord, AF, Chile (45ºS, 73ºW, and provides a comparison with data on shallow soft-bottom polychaetes from Antarctica and other locations of the Magellan Province: Dalcahue Channel, DC (42º22´S, 73º39´W, Puerto Cisnes, Puyuhuapi Channel, PC (44º43´S, 72º42´W and Magellan Straits, MS. AF polychaete fauna comprises 38 species, the macrobenthic taxon being most representative in terms of abundance and species richness. The importance of polychaetes seems to be higher in fjords than in channels. Low numbers of common species were detected among DC, PC, MS and AF, indicating differences along the influence area of the Cape Horn Current or along the Magellan Province. The polychaetes from AF show low affinities with Antarctica; maximum number of common species was observed with the Antarctic Peninsula, whereas the lowest values were recorded from locations in the Ross and Weddell Seas. Coincidence in some ecological attributes between AF and Antarctica indicate that polychaetes may play an important and similar ecological role in both environments.

  5. Polychaetes as environmental indicators revisited

    International Nuclear Information System (INIS)

    Giangrande, Adriana; Licciano, Margherita; Musco, Luigi

    2005-01-01

    The utilization of polychaetes in descriptive ecology is reviewed in the light of recent research especially concerning the biota hard bottom environments. Polychaetes, often linked in the past to the concept of opportunistic species able to proliferate after an increase in organic matter, have played an important role especially with regard to impacted soft-bottom habitats. Increased knowledge of the group, suggests that not only opportunistic species can be utilised as indicators, so that these organisms can be disengaged from the old concept of opportunistic taxa. Moreover, recent researches conducted on this group allowed demonstrating as surrogacy is not always applicable. Among polychaetes inhabiting hard bottom environment, the analysis of family Syllidae appears particularly promising. Studied conducted in our laboratory demonstrated as syllid species decrease in abundance or completely disappear under varying sources of negative impact. The distribution of species also appeared indicative in underlying effects of marine protected areas (MPA) functioning, or in describing different climatic areas within biogeographical sectors. It is obvious that good results can only be obtained on the basis of good taxonomic resolution. We suggested that, in monitoring studies, operational time could be optimized not only by working at a higher-level on the whole invertebrate data set, but by also selecting a particularly indicative group and working at fine level

  6. Polychaetes as environmental indicators revisited

    Energy Technology Data Exchange (ETDEWEB)

    Giangrande, Adriana [Department of Biological and Environmental Sciences and Technology, University of Lecce, Marine Biological Station, 73100 Lecce (Italy)]. E-mail: gianadri@ilenic.unile.it; Licciano, Margherita [Department of Biological and Environmental Sciences and Technology, University of Lecce, Marine Biological Station, 73100 Lecce (Italy); Musco, Luigi [Department of Biological and Environmental Sciences and Technology, University of Lecce, Marine Biological Station, 73100 Lecce (Italy)

    2005-11-15

    The utilization of polychaetes in descriptive ecology is reviewed in the light of recent research especially concerning the biota hard bottom environments. Polychaetes, often linked in the past to the concept of opportunistic species able to proliferate after an increase in organic matter, have played an important role especially with regard to impacted soft-bottom habitats. Increased knowledge of the group, suggests that not only opportunistic species can be utilised as indicators, so that these organisms can be disengaged from the old concept of opportunistic taxa. Moreover, recent researches conducted on this group allowed demonstrating as surrogacy is not always applicable. Among polychaetes inhabiting hard bottom environment, the analysis of family Syllidae appears particularly promising. Studied conducted in our laboratory demonstrated as syllid species decrease in abundance or completely disappear under varying sources of negative impact. The distribution of species also appeared indicative in underlying effects of marine protected areas (MPA) functioning, or in describing different climatic areas within biogeographical sectors. It is obvious that good results can only be obtained on the basis of good taxonomic resolution. We suggested that, in monitoring studies, operational time could be optimized not only by working at a higher-level on the whole invertebrate data set, but by also selecting a particularly indicative group and working at fine level.

  7. Cold seep epifaunal communities on the Hikurangi margin, New Zealand: composition, succession, and vulnerability to human activities.

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    David A Bowden

    Full Text Available Cold seep communities with distinctive chemoautotrophic fauna occur where hydrocarbon-rich fluids escape from the seabed. We describe community composition, population densities, spatial extent, and within-region variability of epifaunal communities at methane-rich cold seep sites on the Hikurangi Margin, New Zealand. Using data from towed camera transects, we match observations to information about the probable life-history characteristics of the principal fauna to develop a hypothetical succession sequence for the Hikurangi seep communities, from the onset of fluid flux to senescence. New Zealand seep communities exhibit taxa characteristic of seeps in other regions, including predominance of large siboglinid tubeworms, vesicomyid clams, and bathymodiolin mussels. Some aspects appear to be novel; however, particularly the association of dense populations of ampharetid polychaetes with high-sulphide, high-methane flux, soft-sediment microhabitats. The common occurrence of these ampharetids suggests they play a role in conditioning sulphide-rich sediments at the sediment-water interface, thus facilitating settlement of clam and tubeworm taxa which dominate space during later successional stages. The seep sites are subject to disturbance from bottom trawling at present and potentially from gas hydrate extraction in future. The likely life-history characteristics of the dominant megafauna suggest that while ampharetids, clams, and mussels exploit ephemeral resources through rapid growth and reproduction, lamellibrachid tubeworm populations may persist potentially for centuries. The potential consequences of gas hydrate extraction cannot be fully assessed until extraction methods and target localities are defined but any long-term modification of fluid flow to seep sites would have consequences for all chemoautotrophic fauna.

  8. Biodiversity of benthic polychaetes from the coastal waters of Paradip, Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.

    ) of macrofauna was higher at shallower depth (near-shore stations) mainly due to the dominance of polychaetes. A total of 79-macrofaunal invertebrate species belonging to 13 phyla and 45 families were identified. The fauna was mainly composed of polychaetes (41...

  9. Molecular identification of polydorid polychaetes (Annelida ...

    African Journals Online (AJOL)

    The early detection and correct identification of polydorid polychaete species is essential as they are often encountered as invasive alien pests in aquaculture facilities or the intertidal where they may modify the ecosystem. Accurate identification is, however, often hampered by high levels of morphological similarity among ...

  10. Earth’s oldest ‘Bobbit worm’ – gigantism in a Devonian eunicidan polychaete

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    Eriksson, Mats E.; Parry, Luke A.; Rudkin, David M.

    2017-01-01

    Whilst the fossil record of polychaete worms extends to the early Cambrian, much data on this group derive from microfossils known as scolecodonts. These are sclerotized jaw elements, which generally range from 0.1–2 mm in size, and which, in contrast to the soft-body anatomy, have good preservation potential and a continuous fossil record. Here we describe a new eunicidan polychaete, Websteroprion armstrongi gen. et sp. nov., based primarily on monospecific bedding plane assemblages from the Lower-Middle Devonian Kwataboahegan Formation of Ontario, Canada. The specimens are preserved mainly as three-dimensional moulds in the calcareous host rock, with only parts of the original sclerotized jaw walls occasionally present. This new taxon has a unique morphology and is characterized by an unexpected combination of features seen in several different Palaeozoic polychaete families. Websteroprion armstrongi was a raptorial feeder and possessed the largest jaws recorded in polychaetes from the fossil record, with maxillae reaching over one centimetre in length. Total body length of the species is estimated to have reached over one metre, which is comparable to that of extant ‘giant eunicid’ species colloquially referred to as ‘Bobbit worms’. This demonstrates that polychaete gigantism was already a phenomenon in the Palaeozoic, some 400 million years ago. PMID:28220886

  11. Control of Polychaetes by Dipping Infected Pearl Oyster on Different Salinity

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    Yani Hadiroseyani

    2007-08-01

    Full Text Available Dip treatment on pearl oysters (Pinctada maxima was conducted in different concentrations of saline water to eliminate boring polychaetes. Results shows that polychaetes leave the osyters which treated on saline water at 0 ppt, 45 ppt, and 60 ppt as long as 15 minutes each. It also shows that the oysters got high survival rate 7 days after the treatment. Key words : Polychaetes, pearl oyster, dipping, salinity   ABSTRAK Pengendalian polikaeta pengebor dengan menggunakan berbagai konsentrasi larutan garam telah dilakukan pada tiram mutiara (Pinctada maxima. Berdasarkan jumlah polikaeta yang keluar, hasil percobaan ini menunjukkan bahwa perendaman dengan konsentrasi garam 0 ppt. 45 ppt, dan 60 ppt selama 15 menit lebih efektif dibandingkan pada konsentrasi 15 dan 30 ppt. Tingkat kelangsungan hidup tiram mutiara yang diamati 7 hari setelah perendaman dalam larutan garam mencapai 100%. Kata kunci : Polikaeta. tiram mutiara, perendaman. salinitas

  12. Polychaete functional diversity in shallow habitats: Shelter from the storm

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    Wouters, Julia M.; Gusmao, Joao B.; Mattos, Gustavo; Lana, Paulo

    2018-05-01

    Innovative approaches are needed to help understanding how species diversity is related to the latitudinal gradient at large or small scales. We have applied a novel approach, by combining morphological and biological traits, to assess the relative importance of the large scale latitudinal gradient and regional morphodynamic drivers in shaping the functional diversity of polychaete assemblages in shallow water habitats, from exposed to estuarine sandy beaches. We used literature data on polychaetes from beaches along the southern and southeastern Brazilian coast together with data on beach types, slope, grain size, temperature, salinity, and chlorophyll a concentration. Generalized linear models on the FDis index for functional diversity calculated for each site and a combined RLQ and fourth-corner analysis were used to investigate relationships between functional traits and environmental variables. Functional diversity was not related to the latitudinal gradient but negatively correlated with grain size and beach slope. Functional diversity was highest in flat beaches with small grain size, little wave exposure and enhanced primary production, indicating that small scale morphodynamic conditions are the primary drivers of polychaete functional diversity.

  13. Metal interactions between the polychaete Branchipolynoe seepensis and the mussel Bathymodiolus azoricus from Mid-Atlantic-Ridge hydrothermal vent fields.

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    Bebianno, Maria João; Cardoso, Cátia; Gomes, Tânia; Blasco, Julian; Santos, Ricardo Serrão; Colaço, Ana

    2018-04-01

    The vent blood-red commensal polynoid polychaete Branchipolynoe seepensis is commonly found in the pallial cavity of the vent mussel Bathymodiolus azoricus, the dominant bivalve species along the Mid-Atlantic-Ridge (MAR) and is known to be kleptoparasitic. Mussels were collected from three hydrothermal vent fields in the MAR: Menez Gwen (850 m depth, MG2, MG3 and MG4), Lucky Strike (1700 m depth, Montségur-MS and Eiffel Tower-ET) and Rainbow (2300 m depth). Polychaetes were absent in all Menez Gwen vent mussels, while the highest percentage was detected in mussels from Lucky Strike, where more than 70% of the mussels had at least one polychaete in their mantle cavity, followed by Rainbow with 33% of mussels with polychaetes. Total metal concentrations (Ag, Cd, Co, Cu, Fe, Mn, Ni and Zn) were determined in polychaetes whole body and in the mussel tissues (gills, digestive gland and mantle). To understand the possible metal interactions between symbiont and host, the activity of antioxidant defence (catalase (CAT), metallothioneins (MTs)), biotransformation enzymes (glutathione-s-transferases (GST)) activities and lipid peroxidation (LPO) were determined in polychaete whole soft tissues and in mussel tissues (gills, digestive gland and mantle). Metal concentrations in polychaetes and mussels tissues indicated that the accumulation patterns were species specific and also influenced by, and possibly dependent upon, the inter- and intra-variation of vent physico-chemistry between hydrothermal fields. Despite not detecting any strong correlations between metal and enzymes activities in polychaetes and mussels, when in presence of polychaetes, mussels presented less metal concentrations in the gills and digestive gland and lower activity of enzymatic biomarkers. This leads to infer that the polychaete plays a role on the detoxification process, and the interaction between the polychaete mussel association is probably an adaptation to metals concentrations at the

  14. Testing the potential for improving quality of sediments impacted by mussel farms using bioturbating polychaete worms

    DEFF Research Database (Denmark)

    Bergström, Per; Carlsson, Marita S; Lindegarth, Mats

    2017-01-01

    Biodeposits from farmed mussels severely influence the biogeochemistry of sediments by increasing the levels of organic matter (OM). Mitigation of such negative impacts is important for the development of sustainable aquaculture operations. As a step towards developing methods for remediation...... of coastal sediments affected by mussel farming, the effects of the polychaete, Hediste diversicolor was evaluated experimentally. In a series of field- and laboratory experiments we tested hypotheses about the effects of polychaetes on sediment oxygen consumption, nutrient fluxes and sulphide pools under...... different polychaete densities and sedimentation regimes. The experimental results support the idea that polychaetes can mitigate negative effects on the benthic environment beneath mussel farms. H. diversicolor oxidized the sediment and generally enhanced the oxygen consumption, and thus the decomposition...

  15. Impacts of the 2011 tsunami on the subtidal polychaete assemblage and the following recolonization in Onagawa Bay, northeastern Japan.

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    Abe, Hirokazu; Kobayashi, Genki; Sato-Okoshi, Waka

    2015-12-01

    The ecological impacts of the 2011 Great East Japan Earthquake and tsunami and the following recolonization of the subtidal benthic polychaete community were examined by monthly pre- and post-quake field surveys that were conducted in Onagawa Bay from 2007 to 2013. Before the tsunami, the species composition in this benthic community was constant and was dominated by cirratulid and magelonid polychaetes. The density and biomass of benthic polychaetes drastically decreased after the tsunami, and the polychaete community fluctuated during the 2 years after the natural disaster. Spionid and capitellid polychaetes were dominant at this period. In June 2013, the community entered a new constant stage dominated by maldanids, which is different from the pre-quake community. Ecological impacts due to chemical pollution were suggested in addition to the tsunami disturbance. These overlapping effects and physical, chemical and biological factors affected the recovery and recolonization of the polychaete community after the natural disaster. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Benthic polychaetes as good indicators of anthropogenic impact

    Digital Repository Service at National Institute of Oceanography (India)

    Sivadas, S.; Ingole, B.S.; Nanajkar, M.

    was highest during post monsoon, mainly due to new recruitment. Pre monsoon is the most stable period for community development when, the fauna was dominated by opportunistic deposit feeding polychaete species. Average abundance ranged from 652-4096 ind m sup...

  17. Metal pollution in a contaminated bay: Relationship between metal geochemical fractionation in sediments and accumulation in a polychaete

    International Nuclear Information System (INIS)

    Fan, Wenhong; Xu, Zhizhen; Wang, Wen-Xiong

    2014-01-01

    Jinzhou Bay in Northern China has been seriously contaminated with metals due to the impacts of smelting activities. In this study, we investigated the relationship between metal accumulation in a deposit-feeding polychaete Neanthes japonica and metal concentration and geochemical fractionation (Cd, Cu, Pb, Zn and Ni) in sediments of Jinzhou Bay. Compared with the historical data, metals in the more mobile geochemical fraction (exchangeable and carbonate fractions) were gradually partitioned into the more stable fraction (Fe–Mn oxides) over time. Metal concentration and geochemical fractionation in sediment significantly affected metal bioavailability and accumulation in polychaetes, except for Ni. Metal accumulation in polychaetes was significantly influenced by Fe or Mn content, and to a lesser degree by organic matter. Prediction of metal bioaccumulation in polychaetes was greatly improved by normalizing metal concentrations to Mn content in sediment. The geochemical fractionation of metals in sediments including the exchangeable, organic matter and Fe–Mn oxides were important in controlling the sediment metal bioavailability to polychaetes. - Highlights: • Metals in contaminated sediments gradually partitioned into the more stable phase over time. • Metal accumulation in polychaetes was more significantly influenced by Fe/Mn content than by organic matter. • Prediction of metal bioaccumulation greatly improved by normalizing metals to Mn content in sediment. • Metals in exchangeable, organic matter and Fe–Mn oxides were important in controlling their bioavailability. - Prediction of metal bioaccumulation in polychaetes was significantly improved by normalizing metal concentrations to Mn content in sediment

  18. Feeding ecology of Bathyraja macloviana (Rajiformes, Arhynchobatidae: a polychaete-feeding skate from the South-west Atlantic

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    Ezequiel Mabragaña

    2005-09-01

    Full Text Available The present paper analyses the diet, feeding strategy and niche width of B. macloviana in a sector of the Argentinean Continental Shelf (ACS. Individuals (n = 147 were collected from 43 sampling stations in late summer and autumn 2001. Thirty one alimentary items in the gut contents were found, with a clear dominance of polychaetes. Crustaceans were secondary alimentary items. The polychaete Travisia kerguelensis was the main food item ingested, followed by Nepthyidae, Sabellidae and Lumbrineridae, while Gammaridae and Cirolanidae were the main items among crustaceans. The niche width and feeding strategy displayed by B. macloviana support the specialisation towards polychaetes throughout this study. Slow motile and infaunal species constitute major preys. The results suggest that this skate actively selects worms, reflecting, in some sense, the composition of the polychaete assemblage, and allowing a low dietary overlap with other sympatric skates of the ACS.

  19. Neurogenesis suggests independent evolution of opercula in serpulid polychaetes

    DEFF Research Database (Denmark)

    Brinkmann, Nora; Wanninger, Andreas

    2009-01-01

    BACKGROUND: The internal phylogenetic relationships of Annelida, one of the key lophotrochozoan lineages, are still heavily debated. Recent molecular analyses suggest that morphologically distinct groups, such as the polychaetes, are paraphyletic assemblages, thus questioning the homology...

  20. Record of bi-operculate fouling serpulid polychaete, Hydroides operculatus (Treadwell, 1929) from Diu, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Kubal, P.; Sukumaran, S.; Vijapure, T.

    is an advanced ontogenic stage of the polychaete rather than a different taxon. Such stages are transient and therefore rarely seen in natural populations. Polychaete species identification is intrinsic to many ecological and environmental studies. Therefore...

  1. The market features of imported non-indigenous polychaetes in Portugal and consequent ecological concerns

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    Pedro Fidalgo e Costa

    2006-12-01

    Full Text Available The importance of the market for polychaetes dramatically increased after the discovery of their potential as food in aquaculture. In Portugal, the gathering of polychaetes solely from natural populations is not sufficient to meet market demand, both as bait for sea anglers and as a food item in aquaculture. The requests for worms to polychaete dealers by Portuguese and Spanish seafarms have increased during recent years. Due to the lack of intensive culture of these worms in Portugal and the proximity of southern Spanish farms, a large component of imported polychaetes that arrive in Portugal at Lisbon Airport go directly to Spain by road. In 2002 and 2003 a total of 12,728,379 and 16,866,839 polychaetes respectively were imported to Europe via Lisbon Airport from China and the USA. In 2003 the imports from China and the USA realised 716,180 and 291,845 US dollars respectively. Two species were reported to have been imported in these years, namely the Korean blue ragworm Perinereis aibuhitensis and the American bloodworm Glycera dibranchiata. Imports of non-indigenous species, which are traded and sold alive, may increase the risk of accidental introduction into the wild. This is of special concern as Perinereis aibuhitensis has been successfully reared in captivity within the range of environmental conditions existing in the Ria Formosa coastal lagoon. Other risks associated with introduced species are the transport of foreign pathogens and other associated non-native organisms, which may act as carriers of disease.

  2. Ecological implications of changes in polychaetes population in a shallow Danish estuary

    DEFF Research Database (Denmark)

    Delefosse, Matthieu

    Burrowing polychaetes are typically the most numerous and active class among macrobenthic infauna in Danish estuaries. Their ecological role is well-recognized and has been often associated with their bioturbating activities. Construction and maintenance of galleries as well as ingestion and defe......Burrowing polychaetes are typically the most numerous and active class among macrobenthic infauna in Danish estuaries. Their ecological role is well-recognized and has been often associated with their bioturbating activities. Construction and maintenance of galleries as well as ingestion...... and defecation displace sediment particles. Ventilation of their burrow irrigates the sediment. These activities transform the environment for other species: from microbes to plants (MS5). Given the important relations between bioturbating polychaetes and their ecosystem, any significant changes in population...... of a key species may have consequent impact on the ecosystem. The introduction of non-native species is an important vector of change for the often species-poor benthic community of Danish estuaries. Non-native species may bring new functions but also interact with native fauna species. The work presented...

  3. Biotransformation of the polycyclic aromatic hydrocarbon pyrene by the marine polychaete Nereis virens

    DEFF Research Database (Denmark)

    Jørgensen, Anne; Giessing, Anders M. B.; Rasmussen, Lene Juel

    2005-01-01

    In vivo and in vitro biotransformation of the polycyclic aromatic hydrocarbon (PAH) pyrene was investigated in the marine polychaete Nereis virens. Assays were designed to characterize phase I and II enzymes isolated from gut tissue. High-pressure liquid chromatography measurement of 1-hydroxypyr......In vivo and in vitro biotransformation of the polycyclic aromatic hydrocarbon (PAH) pyrene was investigated in the marine polychaete Nereis virens. Assays were designed to characterize phase I and II enzymes isolated from gut tissue. High-pressure liquid chromatography measurement of 1...

  4. Distributional patterns of shallow-water polychaetes in the Magellan region: a zoogeographical and ecological synopsis

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    Américo Montiel San Martín

    2005-12-01

    Full Text Available The zoogeography of polychaete annelids was described for the Magellan region. This work considered information available from 19 expeditions carried out in the last 124 years of polychaete taxonomic research around the southernmost tip of the South American continental shelf. The polychaete fauna of the Magellan region comprised a total of 431 species belonging to 108 genera and 41 families. MDS and ANOSIM analyses showed the Magellan region to be divided into two subregions, one on the Pacific side of the tip of South America and one on the Atlantic side. These subregions showed a low percentage of “endemic species” ( 70% of the species recorded for the whole Magellan region showed a wide distribution range, and there were especially high affinities with Antarctic and Subantarctic areas. We suggest that the opening of the Straits of Magellan created a new pathway for enhanced exchange of faunal elements between the Pacific and the Atlantic. Transport of larvae via easterly directed currents of the West Wind Drift plays an important role in current distribution patterns of polychaete fauna around the tip of South America.

  5. On some Polychaetous Annelids from Curaçao

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    Horst, R.

    1922-01-01

    Though we know already a rather large number of Polychaetous Annelids from the Caribbean Sea, hitherto, as far as I know, no Annelids have been described from the coast of the island Curaçao and I therefore was very glad, that my colleague Dr. VAN DER HORST kindly placed in my hands for

  6. Population structure and growth of polydorid polychaetes that infest ...

    African Journals Online (AJOL)

    Polydorid polychaetes can infest cultured abalone thereby reducing productivity. In order to effectively control these pests, their reproductive biology must be understood. The population dynamics and reproduction of polydorids infesting abalone Haliotis midae from two farms in South Africa is described using a ...

  7. [Progress of heterotrophic studies on symbiotic corals].

    Science.gov (United States)

    Yang, Yang-Chu-Qiao; Hong, Wen Ting; Wang, Shu Hong

    2017-12-01

    Heterotrophy of zooxanthellae symbiotic corals refers to the nutrition directly coming from food absorption, not the nutrition obtained from photosynthesis. Most ex situ propagation of symbiotic corals focused on the effects of irradiation, flow rate and water quality on corals, few of them involved in the demand and supply of coral heterotrophic nutrition. This paper reviewed the significance of heterotrophic nutrient supply to symbiotic corals from the sources of coral heterotrophic nutrition, the factors affecting the supply of coral heterotrophic nutrient, and the methods of how to study the coral heterotrophy. In general, the research of coral heterotrophy is just at the beginning stage, and future studies should focus on the inherent mechanism of coral feeding selection and developing more effective research methods.

  8. Sewage-induced disturbance on polychaetes inhabiting intertidal mussel beds of Brachidontes rodriguezii off Mar del Plata (SW Atlantic, Argentina.

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    Rodolfo Elías

    2006-12-01

    Full Text Available Continuous and short-term disturbances are produced on intertidal Brachidontes rodriguezii mussel beds by the sewage outfall of Mar del Plata, SW Atlantic. The effects on the associated polychaetes living on and between mussels were investigated, in both the spatial and short-term temporal scales. Multivariate methods show that the polychaete fauna was influenced by tidal level, total amount of sediment accumulated between mussels, distance from the sewage outfall, organic carbon of interstitial sediments, and sewage volume before and after the summer season. Environmental variables in the water column fitted with a spatial and temporal organic gradient. Capitella ‘capitata’ sp. showed typical opportunistic behaviour in relation to organic enrichment, as did Neanthes succinea, both being numerically dominant near the sewage discharge. Cirratulus sp., Caulleriella alata, and Boccardia polybranchia were common at intermediate distances from the outfall. Syllis prolixa, S. gracilis, and Protoariciella uncinata reached their highest abundance at intermediate stations and were characteristic of the control site. Close to the outfall mussel density and dominance is low, and opportunist polychaetes successfully colonize organically enriched interstitial sediments. At intermediate distances from the outfall sediments retained by mussels reach their maximum values, and density of polychaetes is also high. The control station is characterized by monolayered mussel beds and very low diversity of polychaetes. Opportunistic polychaetes increase in response to short-term increases of sewage discharge during the summer season (November-March.

  9. Assessment of Heavy Metal Pollution in Sediment and Polychaete ...

    African Journals Online (AJOL)

    Metal pollution in the Mzinga creek mangrove stand was assessed and compared with a relatively pristine mangrove forest at Ras Dege in Dar es Salaam. The concentrations of cadmium, chromium, copper, lead and zinc in sediment and polychaete worms (Capitella sp.) were analyzed by ICP-AES and mercury was ...

  10. Managing the marine aquarium trade: revealing the data gaps using ornamental polychaetes.

    Science.gov (United States)

    Murray, Joanna M; Watson, Gordon J; Giangrande, Adriana; Licciano, Margherita; Bentley, Matt G

    2012-01-01

    The marine aquarium industry has great potential to generate jobs in low-income coastal communities creating incentives for the maintenance of a healthy coral reef, if effectively managed. In the absence of current monitoring or legislation to govern the trade, baseline information regarding the species, number and source location of animals traded is missing despite being critical for its successful management and sustainability. An industry assessment to establish the number and provenance of species of ornamental polychaetes (sabellids and serpulids) traded was undertaken across UK wholesalers and retailers. Six geographical regions exporting fan worms were identified. Singapore contributed the highest percentage of imports, but of only one worm "type" whereas Bali, the second largest source, supplied five different worm "types". Over 50% of UK retailers were supplied by one wholesaler while the remainder were stocked by a mixture of one other wholesaler and/or direct imports from the source country. We estimate that up to 18,500 ornamental polychaetes (16,980 sabellids and 1,018 serpulids) are sold annually in the UK revealing a drastic underestimation of currently accepted trade figures. Incorrect identification (based on exporting region or visual characteristics) of traded animals exacerbates the inaccuracy in market quantification, although identification of preserved sabellids using published keys proved just as inconclusive with high within-species variability and the potential for new or cryptic species. A re-description of the polychaete groups traded using a combination of molecular and morphological techniques is necessary for effective identification and market quantification. This study provides the first assessment of ornamental polychaetes but more importantly highlights the issues surrounding the collection of baseline information necessary to manage the aquarium trade. We recommend that future management should be community based and site

  11. Managing the marine aquarium trade: revealing the data gaps using ornamental polychaetes.

    Directory of Open Access Journals (Sweden)

    Joanna M Murray

    Full Text Available The marine aquarium industry has great potential to generate jobs in low-income coastal communities creating incentives for the maintenance of a healthy coral reef, if effectively managed. In the absence of current monitoring or legislation to govern the trade, baseline information regarding the species, number and source location of animals traded is missing despite being critical for its successful management and sustainability. An industry assessment to establish the number and provenance of species of ornamental polychaetes (sabellids and serpulids traded was undertaken across UK wholesalers and retailers. Six geographical regions exporting fan worms were identified. Singapore contributed the highest percentage of imports, but of only one worm "type" whereas Bali, the second largest source, supplied five different worm "types". Over 50% of UK retailers were supplied by one wholesaler while the remainder were stocked by a mixture of one other wholesaler and/or direct imports from the source country. We estimate that up to 18,500 ornamental polychaetes (16,980 sabellids and 1,018 serpulids are sold annually in the UK revealing a drastic underestimation of currently accepted trade figures. Incorrect identification (based on exporting region or visual characteristics of traded animals exacerbates the inaccuracy in market quantification, although identification of preserved sabellids using published keys proved just as inconclusive with high within-species variability and the potential for new or cryptic species. A re-description of the polychaete groups traded using a combination of molecular and morphological techniques is necessary for effective identification and market quantification. This study provides the first assessment of ornamental polychaetes but more importantly highlights the issues surrounding the collection of baseline information necessary to manage the aquarium trade. We recommend that future management should be community

  12. Polychaetes (Annelida: Polychaeta) described for the Mexican Pacific: an historical review and an updated checklist

    OpenAIRE

    Hernández-Alcántara,Pablo; Tovar-Hernández,María Ana; Solís-Weiss,Vivianne

    2008-01-01

    An updated checklist of the polychaete species described for the Mexican Pacific and an historic review of their study are presented. The taxonomic list includes nomenclature references, data of the type locality and synonyms based on systematic revisions. In the study area, 313 species of polychaetes and 21 genera have been described, of which 278 species are currently valid. Several descriptions (28%) of the valid species failed to indicate the habitat of the type locality. The remaining 19...

  13. A Tri-Oceanic Perspective: DNA Barcoding Reveals Geographic Structure and Cryptic Diversity in Canadian Polychaetes

    Science.gov (United States)

    Carr, Christina M.; Hardy, Sarah M.; Brown, Tanya M.; Macdonald, Tara A.; Hebert, Paul D. N.

    2011-01-01

    Background Although polychaetes are one of the dominant taxa in marine communities, their distributions and taxonomic diversity are poorly understood. Recent studies have shown that many species thought to have broad distributions are actually a complex of allied species. In Canada, 12% of polychaete species are thought to occur in Atlantic, Arctic, and Pacific Oceans, but the extent of gene flow among their populations has not been tested. Methodology/Principal Findings Sequence variation in a segment of the mitochondrial cytochrome c oxidase I (COI) gene was employed to compare morphological versus molecular diversity estimates, to examine gene flow among populations of widespread species, and to explore connectivity patterns among Canada's three oceans. Analysis of 1876 specimens, representing 333 provisional species, revealed 40 times more sequence divergence between than within species (16.5% versus 0.38%). Genetic data suggest that one quarter of previously recognized species actually include two or more divergent lineages, indicating that richness in this region is currently underestimated. Few species with a tri-oceanic distribution showed genetic cohesion. Instead, large genetic breaks occur between Pacific and Atlantic-Arctic lineages, suggesting their long-term separation. High connectivity among Arctic and Atlantic regions and low connectivity with the Pacific further supports the conclusion that Canadian polychaetes are partitioned into two distinct faunas. Conclusions/Significance Results of this study confirm that COI sequences are an effective tool for species identification in polychaetes, and suggest that DNA barcoding will aid the recognition of species overlooked by the current taxonomic system. The consistent geographic structuring within presumed widespread species suggests that historical range fragmentation during the Pleistocene ultimately increased Canadian polychaete diversity and that the coastal British Columbia fauna played a minor

  14. A tri-oceanic perspective: DNA barcoding reveals geographic structure and cryptic diversity in Canadian polychaetes.

    Directory of Open Access Journals (Sweden)

    Christina M Carr

    Full Text Available Although polychaetes are one of the dominant taxa in marine communities, their distributions and taxonomic diversity are poorly understood. Recent studies have shown that many species thought to have broad distributions are actually a complex of allied species. In Canada, 12% of polychaete species are thought to occur in Atlantic, Arctic, and Pacific Oceans, but the extent of gene flow among their populations has not been tested.Sequence variation in a segment of the mitochondrial cytochrome c oxidase I (COI gene was employed to compare morphological versus molecular diversity estimates, to examine gene flow among populations of widespread species, and to explore connectivity patterns among Canada's three oceans. Analysis of 1876 specimens, representing 333 provisional species, revealed 40 times more sequence divergence between than within species (16.5% versus 0.38%. Genetic data suggest that one quarter of previously recognized species actually include two or more divergent lineages, indicating that richness in this region is currently underestimated. Few species with a tri-oceanic distribution showed genetic cohesion. Instead, large genetic breaks occur between Pacific and Atlantic-Arctic lineages, suggesting their long-term separation. High connectivity among Arctic and Atlantic regions and low connectivity with the Pacific further supports the conclusion that Canadian polychaetes are partitioned into two distinct faunas.Results of this study confirm that COI sequences are an effective tool for species identification in polychaetes, and suggest that DNA barcoding will aid the recognition of species overlooked by the current taxonomic system. The consistent geographic structuring within presumed widespread species suggests that historical range fragmentation during the Pleistocene ultimately increased Canadian polychaete diversity and that the coastal British Columbia fauna played a minor role in Arctic recolonization following deglaciation

  15. Integrating a DNA barcoding project with an ecological survey: a case study on temperate intertidal polychaete communities in Qingdao, China

    Science.gov (United States)

    Zhou, Hong; Zhang, Zhinan; Chen, Haiyan; Sun, Renhua; Wang, Hui; Guo, Lei; Pan, Haijian

    2010-07-01

    In this study, we integrated a DNA barcoding project with an ecological survey on intertidal polychaete communities and investigated the utility of CO1 gene sequence as a DNA barcode for the classification of the intertidal polychaetes. Using 16S rDNA as a complementary marker and combining morphological and ecological characterization, some of dominant and common polychaete species from Chinese coasts were assessed for their taxonomic status. We obtained 22 haplotype gene sequences of 13 taxa, including 10 CO1 sequences and 12 16S rDNA sequences. Based on intra- and inter-specific distances, we built phylogenetic trees using the neighbor-joining method. Our study suggested that the mitochondrial CO1 gene was a valid DNA barcoding marker for species identification in polychaetes, but other genes, such as 16S rDNA, could be used as a complementary genetic marker. For more accurate species identification and effective testing of species hypothesis, DNA barcoding should be incorporated with morphological, ecological, biogeographical, and phylogenetic information. The application of DNA barcoding and molecular identification in the ecological survey on the intertidal polychaete communities demonstrated the feasibility of integrating DNA taxonomy and ecology.

  16. Distribution and abundance of macrobenthic polychaetes along the South Indian coast

    Digital Repository Service at National Institute of Oceanography (India)

    Musale, A.S.; Desai, D.V.

    and Capitella capitata the deposit feeders and indicators of organic pollution suggesting the sampled area is organically rich. Polychaete abundance was found to be higher along the west coast and was attributed to loose texture of sediment due to high sand...

  17. Antagonistic interactions between filamentous heterotrophs and the cyanobacterium Nostoc muscorum

    Directory of Open Access Journals (Sweden)

    Wolf Sarah

    2011-09-01

    Full Text Available Abstract Background Little is known about interactions between filamentous heterotrophs and filamentous cyanobacteria. Here, interactions between the filamentous heterotrophic bacteria Fibrella aestuarina (strain BUZ 2 and Fibrisoma limi (BUZ 3 with an axenic strain of the autotrophic filamentous cyanobacterium Nostoc muscorum (SAG 25.82 were studied in mixed cultures under nutrient rich (carbon source present in medium and poor (carbon source absent in medium conditions. Findings F. aestuarina BUZ 2 significantly reduced the cyanobacterial population whereas F. limi BUZ 3 did not. Physical contact between heterotrophs and autotroph was observed and the cyanobacterial cells showed some level of damage and lysis. Therefore, either contact lysis or entrapment with production of extracellular compounds in close vicinity of host cells could be considered as potential modes of action. The supernatants from pure heterotrophic cultures did not have an effect on Nostoc cultures. However, supernatant from mixed cultures of BUZ 2 and Nostoc had a negative effect on cyanobacterial growth, indicating that the lytic compounds were only produced in the presence of Nostoc. The growth and survival of tested heterotrophs was enhanced by the presence of Nostoc or its metabolites, suggesting that the heterotrophs could utilize the autotrophs and its products as a nutrient source. However, the autotroph could withstand and out-compete the heterotrophs under nutrient poor conditions. Conclusions Our results suggest that the nutrients in cultivation media, which boost or reduce the number of heterotrophs, were the important factor influencing the outcome of the interplay between filamentous heterotrophs and autotrophs. For better understanding of these interactions, additional research is needed. In particular, it is necessary to elucidate the mode of action for lysis by heterotrophs, and the possible defense mechanisms of the autotrophs.

  18. Mixotrophic organisms become more heterotrophic with rising temperature

    NARCIS (Netherlands)

    Wilken, S.; Huisman, J.; Naus-Wiezer, S.; van Donk, E.

    2013-01-01

    The metabolic theory of ecology predicts that temperature affects heterotrophic processes more strongly than autotrophic processes. We hypothesized that this differential temperature response may shift mixotrophic organisms towards more heterotrophic nutrition with rising temperature. The hypothesis

  19. Polychaete response to fresh food supply at organically enriched coastal sites: Repercussion on bioturbation potential and trophic structure

    Science.gov (United States)

    Venturini, N.; Pires-Vanin, A. M. S.; Salhi, M.; Bessonart, M.; Muniz, P.

    2011-12-01

    We investigated the vertical distribution, abundance, specific and functional structure of polychaete assemblages at four organically enriched sites. The effects of fresh organic matter input from the water column driving by upwelling were evaluated. Temperature and salinity values indicate the intrusion of South Atlantic Central Water (SACW) in spring, a nutrient-rich water mass. The dominance of the conveyor belt transport (CONV) in the station influenced by SACW, in the spring survey, is associated with fresh organic matter input as indicated by higher amounts of polyunsaturated fatty acids. Conversely, the predominance of the diffusive mixing (DIFF) bioturbation category, in the sites without SACW influence is related to the preferential accumulation of more refractive food resources as indicated by higher concentrations of short chain saturated fatty acids. At the site influenced by SACW, the changes in polychaete assemblages were not all evident during proceeding upwelling conditions, but may persist at the end of the upwelling. Polychaetes in the study area seemed to be limited by the quality but not the quantity of food. The delay in polychaete response to fresh food supply may be related to the organic enrichment and the prevalence of refractory material in the sediments.

  20. Polychaete assemblage of an impacted estuary, Guanabara Bay, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Leonardo Santi

    2009-12-01

    Full Text Available Thirty-eight stations were sampled in Guanabara Bay, Rio de Janeiro, Brazil, to assess the spatio-temporal diversity and biomass of sublittoral polychaetes. Samples were collected during the dry (September 2000 and rainy season (May 2001 in shallow sublittoral sediments. The polychaete spatial composition showed a heterogeneous distribution throughout the bay. A negative gradient of diversity and biomass was observed towards the inner parts of the bay and sheltered areas. A wide azoic area was found inside the bay. Some high-biomass and low-diversity spots were found near a sewage-discharge point. In these areas, the polychaete biomass increased after the rainy season. A diversified polychaete community was identified around the bay mouth, with no dramatic changes of this pattern between the two sampling periods. Deposit-feeders were dominant in the entire study area. The relative importance of carnivores and omnivores increased towards the outer sector, at stations with coarse sediment fractions. Guanabara Bay can be divided into three main zones with respect to environmental conditions and polychaete diversity and biomass patterns: A High polychaete diversity, hydrodynamically exposed areas composed of sandy, oxidized or moderately reduced sediments with normoxic conditions in the water column. B Low diversity and high biomass of deposit and suspension-feeding polychaete species in the middle part of the bay near continental inflows, comprising stations sharing similar proportions of silt, clay and fine sands. C Azoic area or an impoverished polychaete community in hydrodynamically low-energy areas of silt and clay with extremely reduced sediments, high total organic matter content and hypoxic conditions in the water column, located essentially from the mid-bay towards the north sector. High total organic matter content and hypoxic conditions combined with slow water renewal in the inner bay seemed to play a key role in the polychaete

  1. Effect of high organic enrichment of benthic polychaete population in an estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari, Z.A.; Ingole, B.S.; Parulekar, A.H.

    The benthic polychaete fauna of an estuarine region receiving domestic sewage and wastes from a nearby fish landing jetty was compared to that of a site having normal organic enrichment. The population density, biomass and species diversity were...

  2. Genotoxicity of two heavy metal compounds: lead nitrate and cobalt chloride in Polychaete Perinereis cultrifera.

    Science.gov (United States)

    Singh, Nisha; Bhagat, Jacky; Ingole, Baban S

    2017-07-01

    The present study explores the in vivo and in vitro genotoxic effects of lead nitrate, [Pb(NO 3 ) 2 ] a recognized environmental pollutant and cobalt chloride (CoCl 2 ), an emerging environmental pollutant in polychaete Perinereis cultrifera using comet assay. Despite widespread occurrence and extensive industrial applications, no previous published reports on genotoxicity of these compounds are available in polychaete as detected by comet assay. Polychaetes were exposed in vivo to Pb(NO 3 ) 2 (0, 100, 500, and 1000 μg/l) and CoCl 2 (0, 100, 300, and 500 μg/l) for 5 days. At 100 μg/l Pb(NO 3 ) 2 concentration, tail DNA (TDNA) values in coelomocytes were increase by 1.16, 1.43, and 1.55-fold after day 1, day 3, and day 5, whereas, OTM showed 1.12, 2.33, and 2.10-fold increase in in vivo. Pb(NO 3 ) 2 showed a concentration and time-dependent genotoxicity whereas CoCl 2 showed a concentration-dependent genotoxicity in in vivo. A concentration-dependent increase in DNA damage was observed in in vitro studies for Pb(NO 3 ) 2 and CoCl 2 . DNA damage at 500 μg/L showed almost threefold increase in TDNA and approximately fourfold increase in OTM as compared to control in in vitro. Our studies suggest that Pb(NO 3 ) 2 and CoCl 2 have potential to cause genotoxic damage, with Pb(NO 3 ) 2 being more genotoxic in polychaete and should be used more carefully in industrial and other activities. Graphical abstract.

  3. Biotransformation of pharmaceuticals under nitrification, nitratation and heterotrophic conditions

    International Nuclear Information System (INIS)

    Fernandez-Fontaina, E.; Gomes, I.B.; Aga, D.S.; Omil, F.; Lema, J.M.; Carballa, M.

    2016-01-01

    The effect of nitrification, nitratation and heterotrophic conditions on the biotransformation of several pharmaceuticals in a highly enriched nitrifying activated sludge was evaluated in this study by selective activation of ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and heterotrophic bacteria. Nitrifiers displayed a noticeable capacity to process ibuprofen due to hydroxylation by ammonia monooxygenase (AMO) to produce 2-hydroxy-ibuprofen. Naproxen was also biotransformed under nitrifying conditions. On the other hand, heterotrophic bacteria present in the nitrifying activated sludge (NAS) biotransformed sulfamethoxazole. In contrast, both nitrifying and heterotrophic activities were ineffective against diclofenac, diazepam, carbamazepine and trimethoprim. Similar biotransformation rates of erythromycin, roxithromycin and fluoxetine were observed under all conditions tested. Overall, results from this study give more evidence on the role of the different microbial communities present in activated sludge reactors on the biological removal of pharmaceuticals. - Highlights: • The removal of pharmaceuticals in nitrifying activated sludge (NAS) was studied. • Nitrifying activity increases biotransformation rate of ibuprofen and naproxen. • Hydroxylation of ibuprofen by ammonia monooxygenase of ammonia oxidizing bacteria • Heterotrophic activity enhances biotransformation of sulfamethoxazole in NAS. • Recalcitrance of trimethoprim, diclofenac, carbamazepine and diazepam in NAS

  4. Biotransformation of pharmaceuticals under nitrification, nitratation and heterotrophic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Fontaina, E., E-mail: eduardo.fernandez.fontaina@usc.es [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Gomes, I.B. [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Aga, D.S. [Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260 (United States); Omil, F.; Lema, J.M.; Carballa, M. [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain)

    2016-01-15

    The effect of nitrification, nitratation and heterotrophic conditions on the biotransformation of several pharmaceuticals in a highly enriched nitrifying activated sludge was evaluated in this study by selective activation of ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and heterotrophic bacteria. Nitrifiers displayed a noticeable capacity to process ibuprofen due to hydroxylation by ammonia monooxygenase (AMO) to produce 2-hydroxy-ibuprofen. Naproxen was also biotransformed under nitrifying conditions. On the other hand, heterotrophic bacteria present in the nitrifying activated sludge (NAS) biotransformed sulfamethoxazole. In contrast, both nitrifying and heterotrophic activities were ineffective against diclofenac, diazepam, carbamazepine and trimethoprim. Similar biotransformation rates of erythromycin, roxithromycin and fluoxetine were observed under all conditions tested. Overall, results from this study give more evidence on the role of the different microbial communities present in activated sludge reactors on the biological removal of pharmaceuticals. - Highlights: • The removal of pharmaceuticals in nitrifying activated sludge (NAS) was studied. • Nitrifying activity increases biotransformation rate of ibuprofen and naproxen. • Hydroxylation of ibuprofen by ammonia monooxygenase of ammonia oxidizing bacteria • Heterotrophic activity enhances biotransformation of sulfamethoxazole in NAS. • Recalcitrance of trimethoprim, diclofenac, carbamazepine and diazepam in NAS.

  5. Heterotrophic cultivation of microalgae for pigment production: A review.

    Science.gov (United States)

    Hu, Jianjun; Nagarajan, Dillirani; Zhang, Quanguo; Chang, Jo-Shu; Lee, Duu-Jong

    Pigments (mainly carotenoids) are important nutraceuticals known for their potent anti-oxidant activities and have been used extensively as high end health supplements. Microalgae are the most promising sources of natural carotenoids and are devoid of the toxic effects associated with synthetic derivatives. Compared to photoautotrophic cultivation, heterotrophic cultivation of microalgae in well-controlled bioreactors for pigments production has attracted much attention for commercial applications due to overcoming the difficulties associated with the supply of CO 2 and light, as well as avoiding the contamination problems and land requirements in open autotrophic culture systems. In this review, the heterotrophic metabolic potential of microalgae and their uses in pigment production are comprehensively described. Strategies to enhance pigment production under heterotrophic conditions are critically discussed and the challenges faced in heterotrophic pigment production with possible alternative solutions are presented. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Errant polychaetes of the continental plattaform of Tamaulipas, México.

    Directory of Open Access Journals (Sweden)

    V. Hugo Delgado-Blas

    2014-06-01

    Full Text Available 24 species of errant polychaetes have been recorded for the eastern Mexican continental shelf: Two Phyllodocidae, one Pilargidae, two Syllicdae, four Nereididae, two Glyceridae, two Goniadidae, three Nephtyidae, two Onuphidae, five Lumbrineridae y one Dorvilleidae. Two of these were the first to be recorded in Mexico, two from Mexican waters in the Gulf of Mexico and 11 new ones recorded in Tamaulipas.

  7. Thermal adaptation of heterotrophic soil respiration in laboratory microcosms.

    Science.gov (United States)

    Mark A. Bradford; Brian W. Watts; Christian A. Davies

    2010-01-01

    Respiration of heterotrophic microorganisms decomposing soil organic carbon releases carbon dioxide from soils to the atmosphere. In the short term, soil microbial respiration is strongly dependent on temperature. In the long term, the response of heterotrophic soil respiration to temperature is uncertain. However, following established evolutionary tradeoffs, mass-...

  8. Partitioning autotrophic and heterotrophic respiration at Howland Forest

    Science.gov (United States)

    Carbone, Mariah; Hollinger, Dave; Davidson, Eric; Savage, Kathleen; Hughes, Holly

    2015-04-01

    Terrestrial ecosystem respiration is the combined flux of CO2 to the atmosphere from above- and below-ground, plant (autotrophic) and microbial (heterotrophic) sources. Flux measurements alone (e.g., from eddy covariance towers or soil chambers) cannot distinguish the contributions from these sources, which may change seasonally and respond differently to temperature and moisture. The development of improved process-based models that can predict how plants and microbes respond to changing environmental conditions (on seasonal, interannual, or decadal timescales) requires data from field observations and experiments to distinguish among these respiration sources. We tested the viability of partitioning of soil and ecosystem respiration into autotrophic and heterotrophic components with different approaches at the Howland Forest in central Maine, USA. These include an experimental manipulation using the classic root trenching approach and targeted ∆14CO2 measurements. For the isotopic measurements, we used a two-end member mass balance approach to determine the fraction of soil respiration from autotrophic and heterotrophic sources. When summed over the course of the growing season, the trenched chamber flux (heterotrophic) accounted for 53 ± 2% of the total control chamber flux. Over the four different 14C sampling periods, the heterotrophic component ranged from 35-55% and the autotrophic component ranges 45-65% of the total flux. Next steps will include assessing the value of the flux partitioning for constraining a simple ecosystem model using a model-data fusion approach to reduce uncertainties in estimates of NPP and simulation of future soil C stocks and fluxes.

  9. Two-stage heterotrophic and phototrophic culture strategy for algal biomass and lipid production.

    Science.gov (United States)

    Zheng, Yubin; Chi, Zhanyou; Lucker, Ben; Chen, Shulin

    2012-01-01

    A two-stage heterotrophic and phototrophic culture strategy for algal biomass and lipid production was studied, wherein high density heterotrophic cultures of Chlorellasorokiniana serve as seed for subsequent phototrophic growth. The data showed growth rate, cell density and productivity of heterotrophic C.sorokiniana were 3.0, 3.3 and 7.4 times higher than phototrophic counterpart, respectively. Hetero- and phototrophic algal seeds had similar biomass/lipid production and fatty acid profile when inoculated into phototrophic culture system. To expand the application, food waste and wastewater were tested as feedstock for heterotrophic growth, and supported cell growth successfully. These results demonstrated the advantages of using heterotrophic algae cells as seeds for open algae culture system. Additionally, high inoculation rate of heterotrophic algal seed can be utilized as an effective method for contamination control. This two-stage heterotrophic phototrophic process is promising to provide a more efficient way for large scale production of algal biomass and biofuels. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Polychaete diversity and its relevance in the rapid environmental assessment of Mumbai Port

    Digital Repository Service at National Institute of Oceanography (India)

    Sukumaran, S.; SaralaDevi, K.

    , 469–474. 11. Reish, D. J., Effect of pollution abatement in Los Angeles harbors. Mar. Pollut. Bull., 1971, 2, 71–74. 12. Levin, L. A., Polychaetes as environmental indicators: response to low oxygen and organic enrichment. Bull. Mar. Sci., 2000, 67...

  11. Trophic transfer of trace metals from the polychaete worm Nereis diversicolor to the polychaete N. virens and the decapod crustacean Palaemonetes varians

    Science.gov (United States)

    Rainbow, P.S.; Poirier, L.; Smith, B.D.; Brix, K.V.; Luoma, S.N.

    2006-01-01

    Diet is an important exposure route for the uptake of trace metals by aquatic invertebrates, with trace metal trophic transfer depending on 2 stages - assimilation and subsequent accumulation by the predator. This study investigated the trophic transfer of trace metals from the sediment-dwelling polychaete worm Nereis diversicolor from metal-rich estuarine sediments in southwestern UK to 2 predators - another polychaete N. virens (Cu, Zn, Pb, Cd, Fe) and the decapod crustacean Palaemonetes varians (Cu, Zn, Pb, Cd, Fe, Ag, As, Mn). N. virens showed net accumulation of Cu, Zn, Pb and Cd from the prey; accumulation increased with increasing prey concentration, but a coefficient of trophic transfer decreased with increasing prey concentration, probably because a higher proportion of accumulated metal in the prey is bound in less trophically available (insoluble) detoxified forms. The trace metal accumulation patterns of P. varians apparently restricted significant net accumulation of metals from the diet of N. diversicolor to just Cd. There was significant mortality of the decapods fed on the diets of metal-rich worms. Metal-rich invertebrates that have accumulated metals from the rich historical store in the sediments of particular SW England estuaries can potentially pass these metals along food chains, with accumulation and total food chain transfer depending on the metal assimilation efficiencies and accumulation patterns of the animal at each trophic level. This trophic transfer may be significant enough to have ecotoxicological effects. ?? Inter-Research 2006.

  12. Impaired growth in the polychaete Armandia brevis exposed to tributyltin in sediment.

    Science.gov (United States)

    Meador, J P; Rice, C A

    2001-03-01

    Juveniles of the opheliid polychaete, Armandia brevis, were exposed to sediment-associated tributyltin (TBT) for 42 days to evaluate toxicity and bioaccumulation. Growth in this species was inhibited in a dose-response fashion by increasing concentrations of TBT. Even though the biota-sediment accumulation factor (BSAF) for TBT declined for the higher sediment concentrations, the total butyltins in tissue increased over all sediment concentrations. At the highest sediment concentrations, polychaetes bioaccumulated less TBT than expected, which was most likely due to reduced uptake and continued metabolism of the parent compound. The less than expected BSAF values exhibited by animals at the exposure concentrations causing severe effects are an important finding for assessing responses in the field. It appears that severe biological effects can occur in long-term experiments without the expected high tissue concentrations; an observation likely explained by altered toxicokinetics. Analysis of variance determined the lowest observed effect concentration for growth to be 191 ng/g sediment dry wt. for 21 days of exposure and 101 ng/g sediment dry wt. at day 42, indicating that 21 days was insufficient for delineating the steady-state toxicity response. When based on regression analysis, the sediment concentration causing a 25% inhibition in growth at 42 days exposure was 93 ng/g dry wt. (total organic carbon = 0.58%). A dose-response association was also determined for polychaete net weight and TBT in tissue. The tissue residue associated with a 25% reduction in growth was 2834 ng/g dry wt. at day 42. A comparison of these results with previous work indicates that juveniles are approximately three times more sensitive than adults to TBT exposure. The sediment concentrations affecting growth in this species are commonly found in urban waterways indicating potentially severe impacts for this and other sensitive species.

  13. Bar-tailed Godwits Limosa l. lapponica eat polychaete worms wherever they winter in Europe

    NARCIS (Netherlands)

    Duijns, Sjoerd; Hidayati, Nur Annis; Piersma, Theunis

    2013-01-01

    Capsule: Across the European wintering range Bar-tailed Godwits Limosa lapponica lapponica selected polychaete worms and especially Ragworms Hediste diversicolor, with differences between areas due to variations in prey availability. Aims: To determine the diet of Bar-tailed Godwits across their

  14. Heterotrophic free-living and particle-bound bacterial cell size in the ...

    Indian Academy of Sciences (India)

    PRAKASH

    the heterotrophic bacterial cell size in the various water bodies studied in this investigation. The possible ... seasonal changes in abundance and cell size of heterotrophic ... data, 1995) physiological stress indicated by the presence of small ...

  15. 1-Hydroxypyrene as a biomarker of PAH exposure in the marine polychaete Nereis diversicolor

    DEFF Research Database (Denmark)

    Tairova, Zhanna; Giessing, Anders; Hansen, Rikke

    2009-01-01

    The possibility of using the pyrene metabolite I-hydroxypyrene as a biomarker of polycyclic aromatic hydrocarbons (PAHs) exposure was investigated by exposure of the marine polychaete Nereis diversicolor to several PAHs in the laboratory. Animals were exposed to pyrene alone and to five different...

  16. Temporal genetic structure in a poecilogonous polychaete: the interplay of developmental mode and environmental stochasticity

    DEFF Research Database (Denmark)

    Hansen, Benni Winding; Kesäniemi, Jenni E; Mustonen, Marina

    2014-01-01

    elegans, a poecilogonous polychaete with within-species variation in developmental mode. P. elegans produces either planktonic, benthic, or intermediate larvae, varying both among and within populations, providing a within-species test of the generality of a relationship between temporal genetic variation...

  17. BACTERIOLOGICAL PROPERTIES OF MARINE WATER IN ADRIATIC FISH FARMS: ENUMERATION OF HETEROTROPHIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Emin Teskeredžić

    2012-12-01

    Full Text Available Aquaculture is currently one of the fastest growing food production sectors in the world. Increase in nutrients and organic wastes lead to general deterioration of water quality. The problem of water quality is associated with both physical and chemical factors, as well as microbiological water quality. Heterotrophic bacteria play an important role in the process of decomposition of organic matter in water environment and indicate eutrophication process. Here we present our experience and knowledge on bacterial properties of marine water in the Adriatic fish farms with European sea bass (Dicentrarchus labrax L., 1758, with an emphasis on enumeration of heterotrophic bacteria in marine water. We applied two temperatures of incubation, as well as two methods for enumeration of heterotrophic bacteria: substrate SimPlate® test and spread plate method on conventional artificial media (Marine agar and Tryptic Soy agar with added NaCl. The results of analysis of bacteriological properties of marine water in the Adriatic fish farms showed that enumeration of heterotrophic bacteria in marine water depends on the applied incubation temperature and media for enumeration. At the same time, the incubation temperature of 22C favours more intense growth of marine heterotrophic bacteria, whereas a SimPlate test gives higher values of heterotrophic bacteria. Volatile values of heterotrophic bacteria during this research indicate a possible deterioration of microbiological water quality in the Adriatic fish farms and a need for regular monitoring of marine water quality.

  18. Heterotrophic cultivation of microalgae for production of biodiesel.

    Science.gov (United States)

    Mohamed, Mohd Shamzi; Wei, Lai Zee; Ariff, Arbakariya B

    2011-08-01

    High cell density cultivation of microalgae via heterotrophic growth mechanism could effectively address the issues of low productivity and operational constraints presently affecting the solar driven biodiesel production. This paper reviews the progress made so far in the development of commercial-scale heterotrophic microalgae cultivation processes. The review also discusses on patentable concepts and innovations disclosed in the past four years with regards to new approaches to microalgal cultivation technique, improvisation on the process flow designs to economically produced biodiesel and genetic manipulation to confer desirable traits leading to much valued high lipid-bearing microalgae strains.

  19. Isolation of heterotrophic diazotrophic bacteria from estuarine surface waters.

    Science.gov (United States)

    Farnelid, Hanna; Harder, Jens; Bentzon-Tilia, Mikkel; Riemann, Lasse

    2014-10-01

    The wide distribution of diverse nitrogenase (nifH) genes affiliated with those of heterotrophic bacteria in marine and estuarine waters indicates ubiquity and an ecologically relevant role for heterotrophic N2 -fixers (diazotrophs) in aquatic nitrogen (N) cycling. However, the lack of cultivated representatives currently precludes an evaluation of their N2 -fixing capacity. In this study, microoxic or anoxic N-free media were inoculated with estuarine Baltic Sea surface water to select for N2 -fixers. After visible growth and isolation of single colonies on oxic plates or in anoxic agar tubes, nifH gene amplicons were obtained from 64 strains and nitrogenase activity, applying the acetylene reduction assay, was confirmed for 40 strains. Two strains, one Gammaproteobacterium affiliated with Pseudomonas and one Alphaproteobacterium affiliated with Rhodopseudomonas were shown to represent established members of the indigenous diazotrophic community in the Baltic Sea, with abundances of up to 7.9 × 10(4) and 4.7 × 10(4)  nifH copies l(-1) respectively. This study reports media for successful isolation of heterotrophic diazotrophs. The applied methodology and the obtained strains will facilitate future identification of factors controlling heterotrophic diazotrophic activity in aquatic environments, which is a prerequisite for understanding and evaluating their ecology and contribution to N cycling at local and regional scales. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Metal toxicity in a sediment-dwelling polychaete: Threshold body concentrations or overwhelming accumulation rates?

    International Nuclear Information System (INIS)

    Carmen Casado-Martinez, M.; Smith, Brian D.; Luoma, Samuel N.; Rainbow, Philip S.

    2010-01-01

    We followed the net accumulation of As, Cu and Zn in the deposit-feeding polychaete Arenicola marina exposed in the laboratory to natural metal-contaminated sediments, one exposure leading to mass mortality between day 10 and 20, and the other not causing lethality over a period of 60 days of exposure. The worms showed lower total accumulated metal concentrations just before mortality occurred (<20 days) at the lethal exposure, than after 30 days of exposure to sediments not causing mortality. Moreover rates of accumulation of As, Cu and Zn were significantly higher in the lethal exposure than in the sublethal exposure. Our results show that it is not possible to link mortality to a critical total body concentration, and we add to a growing body of literature indicating that metal toxicity occurs when organisms cannot cope with overwhelming influx and subsequent accumulation rates. - Laboratory exposures with the deposit-feeding polychaete Arenicola marina suggest that toxicity is not caused by the accumulated concentration of toxic metals in the body of the animal, but by the rate at which the toxic metal is accumulated.

  1. Heterotrophic bacterial populations in tropical sandy beaches

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.; LokaBharathi, P.A.

    Distribution pattern of heterotrophic bacterial flora of three sandy beaches of the west coast of India was studied. The population in these beaches was microbiologically different. Population peaks of halotolerant and limnotolerant forms were...

  2. Investigation of mixotrophic, heterotrophic, and autotrophic growth of Chlorella vulgaris under agricultural waste medium.

    Science.gov (United States)

    Mohammad Mirzaie, M A; Kalbasi, M; Mousavi, S M; Ghobadian, B

    2016-01-01

    Growth of Chlorella vulgaris and its lipid production were investigated under autotrophic, heterotrophic, and mixotrophic conditions. Cheap agricultural waste molasses and corn steep liquor from industries were used as carbon and nitrogen sources, respectively. Chlorella vulgaris grew remarkably under this agricultural waste medium, which resulted in a reduction in the final cost of the biodiesel production. Maximum dry weight of 2.62 g L(-1) was obtained in mixotrophic growth with the highest lipid concentration of 0.86 g L(-1). These biomass and lipid concentrations were, respectively, 140% and 170% higher than autotrophic growth and 300% and 1200% higher than heterotrophic growth. In mixotrophic growth, independent or simultaneous occurrence of autotrophic and heterotrophic metabolisms was investigated. The growth of the microalgae was observed to take place first heterotrophically to a minimum substrate concentration with a little fraction in growth under autotrophic metabolism, and then the cells grew more autotrophically. It was found that mixotrophic growth was not a simple combination of heterotrophic and autotrophic growth.

  3. Factors limiting heterotrophic bacterial production in the southern Pacific Ocean

    Directory of Open Access Journals (Sweden)

    F. Van Wambeke

    2008-05-01

    Full Text Available The role of potential factors limiting bacterial growth was investigated along vertical and longitudinal gradients across the South Eastern Pacific Gyre. The effects of glucose, nitrate, ammonium and phosphate additions on heterotrophic bacterial production (using leucine technique were studied in parallel in unfiltered seawater samples incubated under natural daily irradiance. The enrichments realized on the subsurface showed three types of responses. From 141° W (Marquesas plateau to approx 125° W, bacteria were not bottom-up controlled, as confirmed by the huge potential of growth in non-enriched seawater (median of enhancement factor×39 in 24 h. Within the Gyre (125° W–95° W, nitrogen alone stimulated leucine incorporation rates (median×4.2, but rapidly labile carbon (glucose became a second limiting factor (median×37 when the two elements were added. Finally from the border of the gyre to the Chilean upwelling (95° W–73° W, labile carbon was the only factor stimulating heterotrophic bacterial production. Interaction between phytoplankton and heterotrophic bacterial communities and the direct versus indirect effect of iron and macronutrients on bacterial production were also investigated in four selected sites: two sites on the vicinity of the Marquesas plateau, the centre of the gyre and the Eastern border of the gyre. Both phytoplankton and heterotrophic bacteria were limited by availability of nitrogen within the gyre, but not by iron. Iron limited phytoplankton at Marquesas plateau and at the eastern border of the gyre. However 48 h enrichment experiments were not sufficient to show any clear limitation of heterotrophic bacteria within Marquesas plateau and showed a limitation of these organisms by labile carbon in the eastern border of the Gyre.

  4. Enrichments of methanotrophic-heterotrophic cultures with high poly-β-hydroxybutyrate (PHB) accumulation capacities.

    Science.gov (United States)

    Zhang, Tingting; Wang, Xiaowei; Zhou, Jiti; Zhang, Yu

    2018-03-01

    Methanotrophic-heterotrophic communities were selectively enriched from sewage sludge to obtain a mixed culture with high levels of poly-β-hydroxybutyrate (PHB) accumulation capacity from methane. Methane was used as the carbon source, N 2 as sole nitrogen source, and oxygen and Cu content were varied. Copper proved essential for PHB synthesis. All cultures enriched with Cu could accumulate high content of PHB (43.2%-45.9%), while only small amounts of PHB were accumulated by cultures enriched without Cu (11.9%-17.5%). Batch assays revealed that communities grown with Cu and a higher O 2 content synthesized more PHB, which had a wider optimal CH 4 :O 2 range and produced a high PHB content (48.7%) even though in the presence of N 2 . In all methanotrophic-heterotrophic communities, both methanotrophic and heterotrophic populations showed the ability to accumulate PHB. Although methane was added as the sole carbon source, heterotrophs dominated with abundances between 77.2% and 85.6%. All methanotrophs detected belonged to type II genera, which formed stable communities with heterotrophs of different PHB production capacities. Copyright © 2017. Published by Elsevier B.V.

  5. Modeling how soluble microbial products (SMP) support heterotrophic bacteria in autotroph-based biofilms

    DEFF Research Database (Denmark)

    Merkey, Brian; Rittmann, Bruce E.; Chopp, David L.

    2009-01-01

    . In this paper, we develop and use a mathematical model to describe a model biofilm system that includes autotrophic and heterotrophic bacteria and the key products produced by the bacteria. The model combines the methods of earlier multi-species models with a multi-component biofilm model in order to explore...... the interaction between species via exchange of soluble microbial products (SMP). We show that multiple parameter sets are able to describe the findings of experimental studies, and that heterotrophs growing on autotrophically produced SMP may pursue either r- or K-strategies to sustain themselves when SMP...... is their only substrate. We also show that heterotrophs can colonize some distance from the autotrophs and still be sustained by autotrophically produced SMP. This work defines the feasible range of parameters for utilization of SMP by heterotrophs and the nature of the interactions between autotrophs...

  6. Seasonal genetic variation associated with population dynamics of a poecilogonous polychaete worm

    DEFF Research Database (Denmark)

    Thonig, Anne; Banta, Gary Thomas; Hansen, Benni Winding

    2017-01-01

    Poecilogonous species show variation in developmental mode, with larvae that differ both morphologically and ecologically. The spionid polychaete Pygospio elegans shows variation in developmental mode not only between populations, but also seasonally within populations. We investigated...... differentiation at two of the sites. The seasonal genetic shift correlated with the appearance of new size cohorts in the populations. Additionally, we found that the genetic composition of reproductive individuals did not always reflect the genetic composition of the entire sample, indicating that variance...

  7. Starting a DNA barcode reference library for shallow water polychaetes from the southern European Atlantic coast.

    Science.gov (United States)

    Lobo, Jorge; Teixeira, Marcos A L; Borges, Luisa M S; Ferreira, Maria S G; Hollatz, Claudia; Gomes, Pedro T; Sousa, Ronaldo; Ravara, Ascensão; Costa, Maria H; Costa, Filipe O

    2016-01-01

    Annelid polychaetes have been seldom the focus of dedicated DNA barcoding studies, despite their ecological relevance and often dominance, particularly in soft-bottom estuarine and coastal marine ecosystems. Here, we report the first assessment of the performance of DNA barcodes in the discrimination of shallow water polychaete species from the southern European Atlantic coast, focusing on specimens collected in estuaries and coastal ecosystems of Portugal. We analysed cytochrome oxidase I DNA barcodes (COI-5P) from 164 specimens, which were assigned to 51 morphospecies. To our data set from Portugal, we added available published sequences selected from the same species, genus or family, to inspect for taxonomic congruence among studies and collection location. The final data set comprised 290 specimens and 79 morphospecies, which generated 99 Barcode Index Numbers (BINs) within Barcode of Life Data Systems (BOLD). Among these, 22 BINs were singletons, 47 other BINs were concordant, confirming the initial identification based on morphological characters, and 30 were discordant, most of which consisted on multiple BINs found for the same morphospecies. Some of the most prominent cases in the latter category include Hediste diversicolor (O.F. Müller, 1776) (7), Eulalia viridis (Linnaeus, 1767) (2) and Owenia fusiformis (delle Chiaje, 1844) (5), all of them reported from Portugal and frequently used in ecological studies as environmental quality indicators. Our results for these species showed discordance between molecular lineages and morphospecies, or added additional relatively divergent lineages. The potential inaccuracies in environmental assessments, where underpinning polychaete species diversity is poorly resolved or clarified, demand additional and extensive investigation of the DNA barcode diversity in this group, in parallel with alpha taxonomy efforts. © 2015 John Wiley & Sons Ltd.

  8. Dynamics of pollution-indicator and heterotrophic bacteria in sewage treatment lagoons.

    OpenAIRE

    Legendre, P; Baleux, B; Troussellier, M

    1984-01-01

    The spatio-temporal dynamics of pollution-indicator bacteria and aerobic heterotrophic bacteria were studied in the sewage treatment lagoons of an urban wastewater center after 26 months of biweekly sampling at eight stations in these lagoons. Robust statistical methods of time-series analysis were used to study successional steps (through chronological clustering) and rhythmic behavior through time (through contingency periodogram). The aerobic heterotrophic bacterial community showed two ty...

  9. Transcriptome and quantitative proteome analysis reveals molecular processes associated with larval metamorphosis in the polychaete pseudopolydora vexillosa

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2013-03-01

    Larval growth of the polychaete worm Pseudopolydora vexillosa involves the formation of segment-specific structures. When larvae attain competency to settle, they discard swimming chaetae and secrete mucus. The larvae build tubes around themselves and metamorphose into benthic juveniles. Understanding the molecular processes, which regulate this complex and unique transition, remains a major challenge because of the limited molecular information available. To improve this situation, we conducted high-throughput RNA sequencing and quantitative proteome analysis of the larval stages of P. vexillosa. Based on gene ontology (GO) analysis, transcripts related to cellular and metabolic processes, binding, and catalytic activities were highly represented during larval-adult transition. Mitogen-activated protein kinase (MAPK), calcium-signaling, Wnt/β-catenin, and notch signaling metabolic pathways were enriched in transcriptome data. Quantitative proteomics identified 107 differentially expressed proteins in three distinct larval stages. Fourteen and 53 proteins exhibited specific differential expression during competency and metamorphosis, respectively. Dramatic up-regulation of proteins involved in signaling, metabolism, and cytoskeleton functions were found during the larval-juvenile transition. Several proteins involved in cell signaling, cytoskeleton and metabolism were up-regulated, whereas proteins related to transcription and oxidative phosphorylation were down-regulated during competency. The integration of high-throughput RNA sequencing and quantitative proteomics allowed a global scale analysis of larval transcripts/proteins associated molecular processes in the metamorphosis of polychaete worms. Further, transcriptomic and proteomic insights provide a new direction to understand the fundamental mechanisms that regulate larval metamorphosis in polychaetes. © 2013 American Chemical Society.

  10. Transcriptome and quantitative proteome analysis reveals molecular processes associated with larval metamorphosis in the polychaete pseudopolydora vexillosa

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Sun, Jin; Mok, FloraSy; Liu, Lingli; Qiu, Jianwen; Ravasi, Timothy; Qian, Peiyuan

    2013-01-01

    Larval growth of the polychaete worm Pseudopolydora vexillosa involves the formation of segment-specific structures. When larvae attain competency to settle, they discard swimming chaetae and secrete mucus. The larvae build tubes around themselves and metamorphose into benthic juveniles. Understanding the molecular processes, which regulate this complex and unique transition, remains a major challenge because of the limited molecular information available. To improve this situation, we conducted high-throughput RNA sequencing and quantitative proteome analysis of the larval stages of P. vexillosa. Based on gene ontology (GO) analysis, transcripts related to cellular and metabolic processes, binding, and catalytic activities were highly represented during larval-adult transition. Mitogen-activated protein kinase (MAPK), calcium-signaling, Wnt/β-catenin, and notch signaling metabolic pathways were enriched in transcriptome data. Quantitative proteomics identified 107 differentially expressed proteins in three distinct larval stages. Fourteen and 53 proteins exhibited specific differential expression during competency and metamorphosis, respectively. Dramatic up-regulation of proteins involved in signaling, metabolism, and cytoskeleton functions were found during the larval-juvenile transition. Several proteins involved in cell signaling, cytoskeleton and metabolism were up-regulated, whereas proteins related to transcription and oxidative phosphorylation were down-regulated during competency. The integration of high-throughput RNA sequencing and quantitative proteomics allowed a global scale analysis of larval transcripts/proteins associated molecular processes in the metamorphosis of polychaete worms. Further, transcriptomic and proteomic insights provide a new direction to understand the fundamental mechanisms that regulate larval metamorphosis in polychaetes. © 2013 American Chemical Society.

  11. Evaluation on the microbial interactions of anaerobic ammonium oxidizers and heterotrophs in Anammox biofilm

    DEFF Research Database (Denmark)

    Ni, Bing-Jie; Ruscalleda, Mael; Smets, Barth F.

    2012-01-01

    and the affecting factors were evaluated with both experimental and modeling approaches. Fluorescent in situ hybridization (FISH) analysis illustrated that Anammox bacteria and heterotrophs accounted for 77% and 23% of the total bacteria, respectively, even without addition of an external carbon source....... Experimental results showed the heterotrophs could grow both on SMP and decay released substrate from the metabolism of the Anammox bacteria. However, heterotrophic growth in Anammox biofilm (23%) was significantly lower than that of nitrifying biofilm (30–50%). The model predictions matched well...... with the experimental observations of the bacterial distribution, as well as the nitrogenous transformations in batch and continuous experiments. The modeling results showed that low nitrogen surface loading resulted in a lower availability of SMP leading to low heterotrophic growth in Anammox biofilm, but high...

  12. Heterotrophic bacteria associated with the green alga

    NARCIS (Netherlands)

    Ismail, A.; Ktari, L.; Ahmed, M.; Bolhuis, H.; Bouhaouala-Zahar, B.; Stal, L.J.; Boudabbous, A.; El Bour, M.

    2018-01-01

    Heterotrophic bacteria associated with the green alga Ulva rigida, collected from the coast of Tunisia, were isolated andsubsequently identified by their 16S rRNA gene sequences and by phylogenetic analysis. The 71 isolates belong to four phyla:Proteobacteria (Alpha-and Gamma- subclasses),

  13. Larval growth in the dominant polychaete Polydora ciliata is food-limited in a eutrophic Danish estuary (Isefjord)

    DEFF Research Database (Denmark)

    Pedersen, Troels Møller; Almeda, Rodrigo; Fotel, Frank Lech

    2010-01-01

    Food limitation in larval growth of the spionid polychaete Polydora ciliata was examined in a typical eutrophic estuary, Isefjord, in Denmark. In the field, food availability and the energetic requirements of the P. ciliata larval population were measured during 2 different periods in 2004 and 20...

  14. Survey on Heterotrophic Bacterial Contamination in Bottled Mineral Water by Culture Method

    Directory of Open Access Journals (Sweden)

    Essmaeel Ghorbanalinezhad

    2014-12-01

    Full Text Available Background and Aim: This project focuses on the level of heterotrophic baceria in bottled mineral water which could be a health concern for the elderly, infants, pregnant women and immuno-compromised patients. Materials and Methods: Different brands of bottled water samples were selected randomly and evaluated for their bacteriological quality, using different specific culture media and biochemical tests. Water samples were analyzed within 24 hours of their purchase/collection. Samples were filtered with 0.45 micron and filters were plated in different media. Then media were incubated at 37˚C for 24-48 hours. Results: Morphological study and biochemical tests revealed a number of bacteria in different   brands of  bottled water. Heterotrophic bacteria(Gram positive cocci, Spore forming gram positive bacilli, non spore forming gram positive bacilli, gram negative bacilli, and gram negative coccobacilli; Pseudomonas and Stenotrophomonas counted in 70% of bottled water samples. There were no cases of fecal contamination or the presence of E.coli. Conclusions: Bottled water is not sterile and contains trace amounts of bacteria naturally present or introduced during processing. Testing drinking water for all possible pathogens is complex, time-consuming, and expensive. If only total coliform bacteria are detected in drinking water, the source is probably environmental. Since the significance of non-pathogenic heterotrophic bacteria in relation to health and diseases is not understood, there is an urgent need to establish a maximum limit for the heterotrophic count in the bottled mineral water. Growth conditions play a critical role in the recovery of heterotrophic bacteria in bottled drinking water.

  15. Influence of heterotrophic microbial growth on biological oxidation of pyrite

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, E.A.; Silverstein, J. [University of Nevada, Reno, NV (United States). Dept. of Civil Engineering

    2002-12-15

    Experiments were carried out to examine the possibility that enhanced growth of heterotrophic (non-iron-oxidising) bacteria would inhibit pyrite oxidation by Acidithiobacillus ferroxidans by out-competing the more slowly growing autotrophs for oxygen, nutrients or even attachment sites on the mineral surface. Glucose was added to microcosms containing pyrite, acidic mineral solution and cultures of A-ferrooxidans and Acidiphilium acidophilus under various experimental conditions. Results suggest that encouraging the growth of heterotrophic microorganisms under acid mine drainage conditions may be a feasible strategy for decreasing both the rate and the extent of sulfide mineral oxidation. 43 refs., 8 figs., 3 tabs.

  16. Nutrient and media recycling in heterotrophic microalgae cultures.

    Science.gov (United States)

    Lowrey, Joshua; Armenta, Roberto E; Brooks, Marianne S

    2016-02-01

    In order for microalgae-based processes to reach commercial production for biofuels and high-value products such as omega-3 fatty acids, it is necessary that economic feasibility be demonstrated at the industrial scale. Therefore, process optimization is critical to ensure that the maximum yield can be achieved from the most efficient use of resources. This is particularly true for processes involving heterotrophic microalgae, which have not been studied as extensively as phototrophic microalgae. An area that has received significant conceptual praise, but little experimental validation, is that of nutrient recycling, where the waste materials from prior cultures and post-lipid extraction are reused for secondary fermentations. While the concept is very simple and could result in significant economic and environmental benefits, there are some underlying challenges that must be overcome before adoption of nutrient recycling is viable at commercial scale. Even more, adapting nutrient recycling for optimized heterotrophic cultures presents some added challenges that must be identified and addressed that have been largely unexplored to date. These challenges center on carbon and nitrogen recycling and the implications of using waste materials in conjunction with virgin nutrients for secondary cultures. The aim of this review is to provide a foundation for further understanding of nutrient recycling for microalgae cultivation. As such, we outline the current state of technology and practical challenges associated with nutrient recycling for heterotrophic microalgae on an industrial scale and give recommendations for future work.

  17. Heterotrophic fixation of CO2 in soil

    Czech Academy of Sciences Publication Activity Database

    Šantrůčková, Hana; Bird, M. I.; Elhottová, Dana; Novák, Jaroslav; Picek, T.; Šimek, Miloslav; Tykva, Richard

    2005-01-01

    Roč. 49, č. 2 (2005), s. 218-225 ISSN 0095-3628 R&D Projects: GA ČR(CZ) GA206/02/1036; GA AV ČR(CZ) IAA6066901 Institutional research plan: CEZ:AV0Z60660521 Keywords : heterotrophic fixation * CO2 * soil Subject RIV: EH - Ecology, Behaviour Impact factor: 2.674, year: 2005

  18. Utilization of organic residues using heterotrophic microalgae and insects.

    Science.gov (United States)

    Pleissner, Daniel; Rumpold, Birgit A

    2018-02-01

    Various organic residues occur globally in the form of straw, wood, green biomass, food waste, feces, manure etc. Other utilization strategies apart from anaerobic digestion, composting and incineration are needed to make use of the whole potential of organic residues as sources of various value added compounds. This review compares the cultivation of heterotrophic microalgae and insects using organic residues as nutrient sources and illuminates their potential with regard to biomass production, productivity and yield, and utilization strategies of produced biomasses. Furthermore, cultivation processes as well as advantages and disadvantages of utilization processes are identified and discussed. It was shown that both heterotrophic algae and insects are able to reduce a sufficient amount of organic residues by converting it into biomass. The biomass composition of both organisms is similar which allows similar utilization strategies in food and feed, chemicals and materials productions. Even though insect is the more complex organism, biomass production can be carried out using simple equipment without sterilization and hydrolysis of organic residues. Contrarily, heterotrophic microalgae require a pretreatment of organic residues in form of sterilization and in most cases hydrolysis. Interestingly, the volumetric productivity of insect biomass exceeds the productivity of algal biomass. Despite legal restrictions, it is expected that microalgae and insects will find application as alternative food and feed sources in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Proteomic analysis during larval development and metamorphosis of the spionid polychaete Pseudopolydora vexillosa

    KAUST Repository

    Mok, Flora SY

    2009-12-14

    Background: While the larval-juvenile transition (metamorphosis) in the spionid polychaete Pseudopolydora vexillosa involves gradual morphological changes and does not require substantial development of juvenile organs, the opposite occurs in the barnacle Balanus amphitrite. We hypothesized that the proteome changes during metamorphosis in the spionids are less drastic than that in the barnacles. To test this, proteomes of pre-competent larvae, competent larvae (ready to metamorphose), and juveniles of P. vexillosa were compared using 2-dimensional gel electrophoresis (2-DE), and they were then compared to those of the barnacle.Results: Unlike the significant changes found during barnacle metamorphosis, proteomes of competent P. vexillosa larvae were more similar to those of their juveniles. Pre-competent larvae had significantly fewer protein spots (384 spots), while both competent larvae and juveniles expressed about 660 protein spots each. Proteins up-regulated during competence identified by MALDI-TOF/TOF analysis included a molecular chaperon (calreticulin), a signal transduction regulator (tyrosin activation protein), and a tissue-remodeling enzyme (metallopeptidase).Conclusions: This was the first time to study the protein expression patterns during the metamorphosis of a marine polychaete and to compare the proteomes of marine invertebrates that have different levels of morphological changes during metamorphosis. The findings provide promising initial steps towards the development of a proteome database for marine invertebrate metamorphosis, thus deciphering the possible mechanisms underlying larval metamorphosis in non-model marine organisms. © 2009 Mok et al; licensee BioMed Central Ltd.

  20. Proteomic analysis during larval development and metamorphosis of the spionid polychaete Pseudopolydora vexillosa

    KAUST Repository

    Mok, Flora SY; Thiyagarajan, Vengatesen; Qian, Pei-Yuan

    2009-01-01

    Background: While the larval-juvenile transition (metamorphosis) in the spionid polychaete Pseudopolydora vexillosa involves gradual morphological changes and does not require substantial development of juvenile organs, the opposite occurs in the barnacle Balanus amphitrite. We hypothesized that the proteome changes during metamorphosis in the spionids are less drastic than that in the barnacles. To test this, proteomes of pre-competent larvae, competent larvae (ready to metamorphose), and juveniles of P. vexillosa were compared using 2-dimensional gel electrophoresis (2-DE), and they were then compared to those of the barnacle.Results: Unlike the significant changes found during barnacle metamorphosis, proteomes of competent P. vexillosa larvae were more similar to those of their juveniles. Pre-competent larvae had significantly fewer protein spots (384 spots), while both competent larvae and juveniles expressed about 660 protein spots each. Proteins up-regulated during competence identified by MALDI-TOF/TOF analysis included a molecular chaperon (calreticulin), a signal transduction regulator (tyrosin activation protein), and a tissue-remodeling enzyme (metallopeptidase).Conclusions: This was the first time to study the protein expression patterns during the metamorphosis of a marine polychaete and to compare the proteomes of marine invertebrates that have different levels of morphological changes during metamorphosis. The findings provide promising initial steps towards the development of a proteome database for marine invertebrate metamorphosis, thus deciphering the possible mechanisms underlying larval metamorphosis in non-model marine organisms. © 2009 Mok et al; licensee BioMed Central Ltd.

  1. Proteomic analysis during larval development and metamorphosis of the spionid polychaete Pseudopolydora vexillosa

    Directory of Open Access Journals (Sweden)

    Qian Pei-Yuan

    2009-12-01

    Full Text Available Abstract Background While the larval-juvenile transition (metamorphosis in the spionid polychaete Pseudopolydora vexillosa involves gradual morphological changes and does not require substantial development of juvenile organs, the opposite occurs in the barnacle Balanus amphitrite. We hypothesized that the proteome changes during metamorphosis in the spionids are less drastic than that in the barnacles. To test this, proteomes of pre-competent larvae, competent larvae (ready to metamorphose, and juveniles of P. vexillosa were compared using 2-dimensional gel electrophoresis (2-DE, and they were then compared to those of the barnacle. Results Unlike the significant changes found during barnacle metamorphosis, proteomes of competent P. vexillosa larvae were more similar to those of their juveniles. Pre-competent larvae had significantly fewer protein spots (384 spots, while both competent larvae and juveniles expressed about 660 protein spots each. Proteins up-regulated during competence identified by MALDI-TOF/TOF analysis included a molecular chaperon (calreticulin, a signal transduction regulator (tyrosin activation protein, and a tissue-remodeling enzyme (metallopeptidase. Conclusions This was the first time to study the protein expression patterns during the metamorphosis of a marine polychaete and to compare the proteomes of marine invertebrates that have different levels of morphological changes during metamorphosis. The findings provide promising initial steps towards the development of a proteome database for marine invertebrate metamorphosis, thus deciphering the possible mechanisms underlying larval metamorphosis in non-model marine organisms.

  2. Dynamic metabolic modeling of heterotrophic and mixotrophic microalgal growth on fermentative wastes.

    Directory of Open Access Journals (Sweden)

    Caroline Baroukh

    2017-06-01

    Full Text Available Microalgae are promising microorganisms for the production of numerous molecules of interest, such as pigments, proteins or triglycerides that can be turned into biofuels. Heterotrophic or mixotrophic growth on fermentative wastes represents an interesting approach to achieving higher biomass concentrations, while reducing cost and improving the environmental footprint. Fermentative wastes generally consist of a blend of diverse molecules and it is thus crucial to understand microalgal metabolism in such conditions, where switching between substrates might occur. Metabolic modeling has proven to be an efficient tool for understanding metabolism and guiding the optimization of biomass or target molecule production. Here, we focused on the metabolism of Chlorella sorokiniana growing heterotrophically and mixotrophically on acetate and butyrate. The metabolism was represented by 172 metabolic reactions. The DRUM modeling framework with a mildly relaxed quasi-steady-state assumption was used to account for the switching between substrates and the presence of light. Nine experiments were used to calibrate the model and nine experiments for the validation. The model efficiently predicted the experimental data, including the transient behavior during heterotrophic, autotrophic, mixotrophic and diauxic growth. It shows that an accurate model of metabolism can now be constructed, even in dynamic conditions, with the presence of several carbon substrates. It also opens new perspectives for the heterotrophic and mixotrophic use of microalgae, especially for biofuel production from wastes.

  3. Negative consequences of glacial turbidity for the survival of freshwater planktonic heterotrophic flagellates.

    Science.gov (United States)

    Sommaruga, Ruben; Kandolf, Georg

    2014-02-17

    Heterotrophic (phagotrophic) flagellates are key components of planktonic food webs in freshwater and marine ecosystems because they are the main consumers of bacteria. Although they are ubiquitous in aquatic ecosystems, they were numerically undetectable in turbid glacier-fed lakes. Here we show that glacial particles had negative effects on the survival and growth of heterotrophic flagellates. The effect of glacial particles was concentration-dependent and was caused by their interference with bacterial uptake rather than by physical damage. These results are the first to reveal why establishment of heterotrophic flagellates populations is hindered in very turbid glacial lakes. Because glaciers are vanishing around the world, recently formed turbid meltwater lakes represent an excellent opportunity to understand the environmental conditions that probably shaped the establishment of lake communities at the end of the last glaciation.

  4. Differential expression of proteins and phosphoproteins during larval metamorphosis of the polychaete Capitella sp. I

    Directory of Open Access Journals (Sweden)

    Qian Pei-Yuan

    2011-09-01

    Full Text Available Abstract Background The spontaneous metamorphosis of the polychaete Capitella sp. I larvae into juveniles requires minor morphological changes, including segment formation, body elongation, and loss of cilia. In this study, we investigated changes in the expression patterns of both proteins and phosphoproteins during the transition from larvae to juveniles in this species. We used two-dimensional gel electrophoresis (2-DE followed by multiplex fluorescent staining and MALDI-TOF mass spectrometry analysis to identify the differentially expressed proteins as well as the protein and phosphoprotein profiles of both competent larvae and juveniles. Results Twenty-three differentially expressed proteins were identified in the two developmental stages. Expression patterns of two of those proteins were examined at the protein level by Western blot analysis while seven were further studied at the mRNA level by real-time PCR. Results showed that proteins related to cell division, cell migration, energy storage and oxidative stress were plentifully expressed in the competent larvae; in contrast, proteins involved in oxidative metabolism and transcriptional regulation were abundantly expressed in the juveniles. Conclusion It is likely that these differentially expressed proteins are involved in regulating the larval metamorphosis process and can be used as protein markers for studying molecular mechanisms associated with larval metamorphosis in polychaetes.

  5. Pollution effects on ecobiology of benthic polychaetes in Visakhapatnam Harbour (Bay of Bengal)

    Energy Technology Data Exchange (ETDEWEB)

    Raman, A.V.; Ganapati, P.N.

    1983-02-01

    Rapid urbanization and industrialization of Visakhapatnam and construction of an outer harbour, restricting water flow, have markedly increased the organic load in the inner harbour. Studies of the physico-chemical and biological characteristics of six selected stations along a decreasing gradient of organic pollution have been carried out over a period of two years. The predominantly polychaete benthic fauna occurs in three distinct assemblages: Capitella capitata-Nereis glandicincta in the inner harbour; Cossura coasta-Tharyx marioni in the outer harbour; and a Chloeia-Axiothella-Chaetozone-Nephtys assemblage in the open sea.

  6. Heterotrophic components of soil respiration in pastures and forests in southwestern Amazonia, Acre, Brazil

    Directory of Open Access Journals (Sweden)

    Eric Atlas Davidson

    2008-12-01

    Full Text Available In this paper we present data on soil microbial biomass and heterotrophic respiration in pastures, mature and secondary forests, in order to elucidate their contribution to total CO2 flux from soil to atmosphere. The research was conducted in Southwestern Amazonia, Acre State, Brazil. Microbial biomass was estimated using a variation of the traditional fumigation-extraction method and heterotrophic respiration was measured using respirometry flasks attached to an infrared gas analyzer. Soil microbial biomass and heterotrophic respiration did not differ statistically among pastures, mature and secondary forests. These laboratory results indicate that higher CO2 fluxes from pasture soils measured in situ are probably due to higher root respiration by pasture grasses.

  7. Elevated temperature increases carbon and nitrogen fluxes between phytoplankton and heterotrophic bacteria through physical attachment

    KAUST Repository

    Arandia-Gorostidi, Nestor

    2016-12-06

    Quantifying the contribution of marine microorganisms to carbon and nitrogen cycles and their response to predicted ocean warming is one of the main challenges of microbial oceanography. Here we present a single-cell NanoSIMS isotope analysis to quantify C and N uptake by free-living and attached phytoplankton and heterotrophic bacteria, and their response to short-term experimental warming of 4 °C. Elevated temperature increased total C fixation by over 50%, a small but significant fraction of which was transferred to heterotrophs within 12 h. Cell-to-cell attachment doubled the secondary C uptake by heterotrophic bacteria and increased secondary N incorporation by autotrophs by 68%. Warming also increased the abundance of phytoplankton with attached heterotrophs by 80%, and promoted C transfer from phytoplankton to bacteria by 17% and N transfer from bacteria to phytoplankton by 50%. Our results indicate that phytoplankton-bacteria attachment provides an ecological advantage for nutrient incorporation, suggesting a mutualistic relationship that appears to be enhanced by temperature increases.

  8. Elevated temperature increases carbon and nitrogen fluxes between phytoplankton and heterotrophic bacteria through physical attachment

    KAUST Repository

    Arandia-Gorostidi, Nestor; Weber, Peter K; Alonso-Sá ez, Laura; Moran, Xose Anxelu G.; Mayali, Xavier

    2016-01-01

    Quantifying the contribution of marine microorganisms to carbon and nitrogen cycles and their response to predicted ocean warming is one of the main challenges of microbial oceanography. Here we present a single-cell NanoSIMS isotope analysis to quantify C and N uptake by free-living and attached phytoplankton and heterotrophic bacteria, and their response to short-term experimental warming of 4 °C. Elevated temperature increased total C fixation by over 50%, a small but significant fraction of which was transferred to heterotrophs within 12 h. Cell-to-cell attachment doubled the secondary C uptake by heterotrophic bacteria and increased secondary N incorporation by autotrophs by 68%. Warming also increased the abundance of phytoplankton with attached heterotrophs by 80%, and promoted C transfer from phytoplankton to bacteria by 17% and N transfer from bacteria to phytoplankton by 50%. Our results indicate that phytoplankton-bacteria attachment provides an ecological advantage for nutrient incorporation, suggesting a mutualistic relationship that appears to be enhanced by temperature increases.

  9. Competition between autotrophic and heterotrophic microbial plankton for inorganic nutrients induced by variability in estuarine biophysicochemical conditions

    Science.gov (United States)

    Williams, A.; Quigg, A.

    2016-02-01

    Competition for inorganic nutrients between autotrophic and heterotrophic fractions of microbial plankton (0.2-20μm) was investigated at two stations in a sub-tropical estuary, Galveston Bay, Texas. Competition potential between these groups is enhanced because individuals are similar in size, reducing variability among their nutrient uptake efficiencies. Further, in estuaries, allochthonous supplements to autochthonous carbon may satisfy heterotrophic requirements, allowing alternative factors to limit abundance. The relative abundance of autotrophs and heterotrophs stained with SYBR Green I and enumerated on a Beckman Coulter Gallios flow cytometer were evaluated monthly during a year-long study. Shifts in the relative in situ abundance were significantly related to temperature, dissolved inorganic nitrogen (DIN), phosphorous (Pi), and total organic carbon (TOC) concentrations revealing opposing gradients of limitation by different abiotic factors. In corresponding in vitro nutrient enrichment bioassays the relative contribution of autotrophic or heterotrophic microbial plankton to significant enrichment responses varied. Only during macro- (>20μm) phytoplankton blooms do autotrophic microbial plankton respond to nutrient enrichment. Contrastingly, the heterotrophic microbial plankton responded to nutrient enrichment primarily when temperature limitation was alleviated. Therefore, the potential for autotrophic and heterotrophic microbial plankton competition for limiting nutrients is highest when autotrophic microbial plankton are also competing with larger phytoplankton during bloom events. Based on this evidence, we hypothesize that the autotrophic microbial fraction has a competitive advantage over the heterotrophs for inorganic nutrients in Galveston Bay. The observed microbial competition during estuarine phytoplankton blooms may have important consequences on biogeochemical processes including carbon and nutrient cycling.

  10. Removal of crude petroleum hydrocarbons by heterotrophic bacteria ...

    African Journals Online (AJOL)

    Nitrogenous fertilizer (NPK) plant effluents from NAFCON were used in amending plots of land experimentally polluted with crude oil. Counts of heterotrophic bacteria (THBC) and fungi (TF), and of petroleum utilizing bacteria (PUB) and fungi (PUF) were monitored during an 8 weeks period. Counts obtained showed that ...

  11. Novel insight into the role of heterotrophic dinoflagellates in the fate of crude oil in the sea

    Science.gov (United States)

    Almeda, Rodrigo; Connelly, Tara L.; Buskey, Edward J.

    2014-12-01

    Although planktonic protozoans are likely to interact with dispersed crude oil after a spill, protozoan-mediated processes affecting crude oil pollution in the sea are still not well known. Here, we present the first evidence of ingestion and defecation of physically or chemically dispersed crude oil droplets (1-86 μm in diameter) by heterotrophic dinoflagellates, major components of marine planktonic food webs. At a crude oil concentration commonly found after an oil spill (1 μL L-1), the heterotrophic dinoflagellates Noctiluca scintillans and Gyrodinium spirale grew and ingested ~0.37 μg-oil μg-Cdino-1 d-1, which could represent ~17% to 100% of dispersed oil in surface waters when heterotrophic dinoflagellates are abundant or bloom. Egestion of faecal pellets containing crude oil by heterotrophic dinoflagellates could contribute to the sinking and flux of toxic petroleum hydrocarbons in coastal waters. Our study indicates that crude oil ingestion by heterotrophic dinoflagellates is a noteworthy route by which petroleum enters marine food webs and a previously overlooked biological process influencing the fate of crude oil in the sea after spills.

  12. Polychaetes from the northern part of the Sea of Marmara with the description of a new species of Polydora (Annelida: Polychaeta: Spionidae

    Directory of Open Access Journals (Sweden)

    M. E. ÇINAR

    2015-09-01

    Full Text Available Soft-bottom material collected from the northern part of the Sea of Marmara (off Küçükçekmece included a total of 67 species belonging to 24 polychaete families. Three species (Brania pusilla, Lysidice cf. margaritacea and Sabellaria spinulosa are new records for the Sea of Marmara. Three alien species (Polydora cornuta, Prionospio pulchra and Pseudopolydora paucibranchiata were found at the shallow-water stations. Different polychaete assemblages occurred in the area and the mud percentage of sediment and salinity were the main factors related to their distribution. A new Polydora species, which is mainly characterized in having brownish pigmentation solely on the antero-dorsal sides of the body, and falcate major spines with only a bulge (anterior ones or with a bulge and a small tooth, is described.

  13. Pyruvic Oxime Nitrification and Copper and Nickel Resistance by a Cupriavidus pauculus, an Active Heterotrophic Nitrifier-Denitrifier

    OpenAIRE

    Ramirez, Miguel; Obrzydowski, Jennifer; Ayers, Mary; Virparia, Sonia; Wang, Meijing; Stefan, Kurtis; Linchangco, Richard; Castignetti, Domenic

    2014-01-01

    Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammonium ion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N2) and nitrous oxide (N2O) while heterotrophically nitrifying the organic substrate pyruvic oxime [CH3–C(NOH)–COOH]. Neither N2 nor N2O were produced. Nucleotide and phylogenetic analyses indicated that the organism is a member of a g...

  14. The Biology of Heterotrophic N2-fixing Bacteria in Marine and Estuarine Waters

    DEFF Research Database (Denmark)

    Bentzon-Tilia, Mikkel

    Biological nitrogen (N)2 fixation is of paramount importance for marine N cycling and for life in the oceans in general. It represents the sole mechanism by which microorganisms can channel inert atmospheric N2 gas into biomass and hence it may fuel a significant fraction of primary production...... heterotrophic isolates, this thesis aims at addressing these unknowns. It was found that heterotrophic diazotrophs were present and active in environments previously not associated with N2 fixation e.g. suboxic basins of the Baltic Sea and estuarine surface waters. In these environments they contributed...... with significant amounts fixed N2, suggesting that a reevaluation of the significance of N fixation in suboxic waters and estuarine coastal waters is warranted. It was also documented that heterotrophic diazotrophs could be enriched in culture based on their ability to utilize N2 as the sole N source...

  15. Individual- and population-level effects of the synthetic musk, HHCB, on the deposit-feeding polychaete, Capitella sp. I

    DEFF Research Database (Denmark)

    Ramskov, Tina; Selck, Henriette; Salvito, Daniel

    2009-01-01

    A life table response experiment lasting 120 d was used to investigate the effects of the synthetic polycyclic musk HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8-hexamethylcyclopenta-gamma-2-benzopyrane; 0, 1.5, 26, 123, and 168 mg/kg dry wt sediment) on the life history of the infaunal polychaete...

  16. Differential expression of proteins and phosphoproteins during larval metamorphosis of the polychaete Capitella sp. I

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2011-09-03

    Background: The spontaneous metamorphosis of the polychaete Capitella sp. I larvae into juveniles requires minor morphological changes, including segment formation, body elongation, and loss of cilia. In this study, we investigated changes in the expression patterns of both proteins and phosphoproteins during the transition from larvae to juveniles in this species. We used two-dimensional gel electrophoresis (2-DE) followed by multiplex fluorescent staining and MALDI-TOF mass spectrometry analysis to identify the differentially expressed proteins as well as the protein and phosphoprotein profiles of both competent larvae and juveniles.Results: Twenty-three differentially expressed proteins were identified in the two developmental stages. Expression patterns of two of those proteins were examined at the protein level by Western blot analysis while seven were further studied at the mRNA level by real-time PCR. Results showed that proteins related to cell division, cell migration, energy storage and oxidative stress were plentifully expressed in the competent larvae; in contrast, proteins involved in oxidative metabolism and transcriptional regulation were abundantly expressed in the juveniles.Conclusion: It is likely that these differentially expressed proteins are involved in regulating the larval metamorphosis process and can be used as protein markers for studying molecular mechanisms associated with larval metamorphosis in polychaetes. © 2011 Chandramouli et al; licensee BioMed Central Ltd.

  17. Differential expression of proteins and phosphoproteins during larval metamorphosis of the polychaete Capitella sp. I

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Soo, Lisa; Qian, Pei-Yuan

    2011-01-01

    Background: The spontaneous metamorphosis of the polychaete Capitella sp. I larvae into juveniles requires minor morphological changes, including segment formation, body elongation, and loss of cilia. In this study, we investigated changes in the expression patterns of both proteins and phosphoproteins during the transition from larvae to juveniles in this species. We used two-dimensional gel electrophoresis (2-DE) followed by multiplex fluorescent staining and MALDI-TOF mass spectrometry analysis to identify the differentially expressed proteins as well as the protein and phosphoprotein profiles of both competent larvae and juveniles.Results: Twenty-three differentially expressed proteins were identified in the two developmental stages. Expression patterns of two of those proteins were examined at the protein level by Western blot analysis while seven were further studied at the mRNA level by real-time PCR. Results showed that proteins related to cell division, cell migration, energy storage and oxidative stress were plentifully expressed in the competent larvae; in contrast, proteins involved in oxidative metabolism and transcriptional regulation were abundantly expressed in the juveniles.Conclusion: It is likely that these differentially expressed proteins are involved in regulating the larval metamorphosis process and can be used as protein markers for studying molecular mechanisms associated with larval metamorphosis in polychaetes. © 2011 Chandramouli et al; licensee BioMed Central Ltd.

  18. Transcriptional changes underlying elemental stoichiometry shifts in a marine heterotrophic bacterium

    Directory of Open Access Journals (Sweden)

    Leong-Keat eChan

    2012-05-01

    Full Text Available Marine bacteria drive the biogeochemical processing of oceanic dissolved organic carbon (DOC, a 750-Tg C reservoir that is a critical component of the global C cycle. Catabolism of DOC is thought to be regulated by the biomass composition of heterotrophic bacteria, as cells maintain a C:N:P ratio of ~50:10:1 during DOC processing. Yet a complicating factor in stoichiometry-based analyses is that bacteria can change the C:N:P ratio of their biomass in response to resource composition. We investigated the physiological mechanisms of resource-driven shifts in biomass stoichiometry in continuous cultures of the marine heterotrophic bacterium Ruegeria pomeroyi (a member of the Roseobacter clade under four element limitation regimes (C, N, P, and S. Microarray analysis indicated that the bacterium scavenged for alternate sources of the scarce element when cells were C-, N-, or P-limited; reworked the ratios of biomolecules when C- and P- limited; and exerted tighter control over import/export and cytoplasmic pools when N-limited. Under S-limitation, a scenario not existing naturally for surface ocean microbes, stress responses dominated transcriptional changes. Resource-driven changes in C:N ratios of up to 2.5-fold and in C:P ratios of up to 6-fold were measured in R. pomeroyi biomass. These changes were best explained if the C and P content of the cells was flexible in the face of shifting resources but N content was not, achieved through the net balance of different transcriptional strategies. The cellular-level metabolic trade-offs that govern biomass stoichiometery in R. pomeroyi may have implications for global carbon cycling. Strong homeostatic responses to N limitation by heterotrophic marine bacteria would intensify competition with autotrophs. Modification of cellular inventories in C- and P-limited heterotrophs would vary the elemental ratio of particulate organic matter sequestered in the deep ocean.

  19. Alien freshwater polychaetes Hypania invalida (Grube 1860 and Laonome calida Capa 2007 in the Upper Odra River (Baltic Sea catchment area

    Directory of Open Access Journals (Sweden)

    Pabis Krzysztof

    2017-01-01

    Full Text Available Two polychaete species, Hypania invalida and Laonome calida, were found in the Upper Odra River in 2016. Both species were recorded close to a natural river bank down to 1 m depths. They inhabited sandy-gravelly and sandy-muddy sediments. H. invalida is an alien invasive Ponto-Caspian species, previously known in Poland from the Odra River estuary only. Our results may indicate a further rapid dispersal of H. invalida upstream the Odra River or an accidental introduction. This study is the first record of L. calida in the Baltic Sea catchment. This Australian species has been recently introduced into Europe. Prior to this study, it had been reported from Dutch rivers only. The present data suggest accidental introduction of the species to European rivers; however, our findings show an urgent need for a close monitoring of the polychaete in Europe.

  20. Morphological distinction between estuarine polychaetes: Laeonereis culveri and L. nota (Phyllodocida: Nereididae).

    Science.gov (United States)

    de Jesus-Flores, Citlalli; Salazar-González, S Alejandro; Salazar-Vallejo, Sergio I

    2016-03-01

    The family Nereididae includes more than 500 polychaete species described worldwide, and includes species common in many benthic environments, but some other species may tolerate freshwater or can even thrive in humid substrates in tropical forests. In estuarine environments, nereidid polychaetes can be abundant and relevant as a food source for resident or migratory birds. Laeonereis culveri (Webster, 1879) is a common estuarine species found in tropical and subtropical Atlantic American shores and was described from New Jersey; its median and posterior parapodia have upper notopodial ligules usually longer than the lower ones, and the latter are parallel to the notaciculae throughout the body. L. culveri distribution is from Connecticut to central Argentina; however, this wide distribution might be due to the inclusion of several other species as junior synonyms, despite that some morphological differences were found between them. One of such species is L. nota (Treadwell, 1941), that was described from Texas; its parapodia have notopodial ligules of about the same size, and the lower ones are oblique to the notaciculae. In order to clarify the differences between these two species, and to define which inhabits the Northwestern Caribbean region, topotype materials from these two species and specimens from Chetumal Bay were collected, and their morphological features were compared. Our results indicated that L. culveri and L. nota are different species and that the latter is found in Chetumal Bay. On the basis of mature specimens, L. culveri is hereby restricted to the Northern Gulf of Mexico and Northwestern Atlantic Ocean, and L. nota are reinstated and its distribution extends from Texas, in the Gulf of Mexico to Chetumal Bay, in the Northwestern Caribbean Sea. A key to identify all species in Laeonereis Hartman (1945) is also included.

  1. Temperature regulation of marine heterotrophic prokaryotes increases latitudinally as a breach between bottom-up and top-down controls

    KAUST Repository

    Moran, Xose Anxelu G.; Gasol, Josep M.; Pernice, Massimo C.; Mangot, Jean-Franç ois; Massana, Ramon; Lara, Elena; Vaqué , Dolors; Duarte, Carlos M.

    2017-01-01

    Planktonic heterotrophic prokaryotes make up the largest living biomass and process most organic matter in the ocean. Determining when and where the biomass and activity of heterotrophic prokaryotes are controlled by resource availability (bottom

  2. Indirect control of the intracellular nitrate pool of intertidal sediment by the polychaete Hediste diversicolor

    DEFF Research Database (Denmark)

    Heisterkamp, Ines Maria; Kamp, Anja; Schramm, Angela T.

    2012-01-01

    for anaerobic respiration processes. The origin and some of the ecological controls of this intracellular nitrate pool were investigated in a laboratory experiment. Sediment microcosms were set up with and without the abundant polychaete Hediste diversicolor that is known to stim- ulate nitrate production...... that of the photopigments chlorophyll a and fucoxanthin, strongly suggesting that diatoms were the main nitrate-storing organisms. Intra- cellular nitrate formation is thus stimulated by the interaction of phylogenetically distant groups of organisms: worms enhance nitrification by feeding on particulate organic matter...

  3. Pyruvic oxime nitrification and copper and nickel resistance by a Cupriavidus pauculus, an active heterotrophic nitrifier-denitrifier.

    Science.gov (United States)

    Ramirez, Miguel; Obrzydowski, Jennifer; Ayers, Mary; Virparia, Sonia; Wang, Meijing; Stefan, Kurtis; Linchangco, Richard; Castignetti, Domenic

    2014-01-01

    Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammonium ion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N2) and nitrous oxide (N2O) while heterotrophically nitrifying the organic substrate pyruvic oxime [CH3-C(NOH)-COOH]. Neither N2 nor N2O were produced. Nucleotide and phylogenetic analyses indicated that the organism is a member of a genus (Cupriavidus) known for its resistance to metals and its metabolism of xenobiotics. The microbe (a Cupriavidus pauculus designated as C. pauculus strain UM1) was examined for its ability to perform heterotrophic nitrification in the presence of Cu(2+) and Ni(2+) and to metabolize the xenobiotic phenol. The bacterium heterotrophically nitrified well when either 1 mM Cu(2+) or 0.5 mM Ni(2+) was present in either enriched or minimal medium. The organism also used phenol as a sole carbon source in either the presence or absence of 1 mM Cu(2+) or 0.5 mM Ni(2+). The ability of this isolate to perform a number of different metabolisms, its noteworthy resistance to copper and nickel, and its potential use as a bioremediation agent are discussed.

  4. Primary and heterotrophic productivity relate to multikingdom diversity in a hypersaline mat

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, Hans C.; Brislawn, Colin J.; Dana, Karl; Flores-Wentz, Tobias; Cory, Alexandra B.; Fansler, Sarah J.; Fredrickson, James K.; Moran, James J.

    2017-10-01

    Benthic microbial ecosystems are widespread yet knowledge gaps still remain on the relationships between the diversity of species across kingdoms and productivity. Here, we ask two fundamental questions: 1) How does species diversity relate to the rates of primary and heterotrophic productivity? 2) How do diel variations in light-energy inputs influence productivity and microbiome diversity? To answer these questions, microbial mats from a magnesium sulfate hypersaline Lake were used to establish microcosms. Both the number and relatedness between bacterial and eukaryotic taxa in the microbiome were assayed via amplicon based sequencing of 16S and 18S rRNA genes over two diel cycles. These results correlated with biomass productivity obtained from substrate-specific 13C stable isotope incorporation that enabled comparisons between primary and heterotrophic productivity. Both bacterial and eukaryotic species richness and evenness were related only to the rates of 13C labeled glucose and acetate biomass incorporation. Interestingly, measures of these heterotrophic relationships changed from positive and negative correlations depending on carbon derived from glucose and acetate, respectively. Bacterial and eukaryotic diversity of this ecosystem is also controlled, in part, energy constraints imposed by changing irradiance over a diel cycle.

  5. Draft Genome Sequence of Limnobacter sp. Strain CACIAM 66H1, a Heterotrophic Bacterium Associated with Cyanobacteria

    OpenAIRE

    da Silva, F?bio Daniel Flor?ncio; Lima, Alex Ranieri Jer?nimo; Moraes, Pablo Henrique Gon?alves; Siqueira, Andrei Santos; Dall?Agnol, Leonardo Teixeira; Bara?na, Anna Rafaella Ferreira; Martins, Luisa Car?cio; Oliveira, Karol Guimar?es; de Lima, Clayton Pereira Silva; Nunes, M?rcio Roberto Teixeira; Vianez-J?nior, Jo?o L?dio Silva Gon?alves; Gon?alves, Evonnildo Costa

    2016-01-01

    Ecological interactions between cyanobacteria and heterotrophic prokaryotes are poorly known. To improve the genomic studies of heterotrophic bacterium-cyanobacterium associations, the draft genome sequence (3.2 Mbp) of Limnobacter sp. strain CACIAM 66H1, found in a nonaxenic culture of Synechococcus sp. (cyanobacteria), is presented here.

  6. Calorimetry and thermodynamic aspects of heterotrophic, mixotrophic, and phototrophic growth

    NARCIS (Netherlands)

    Stockar, von U.; Marison, I.; Janssen, M.G.J.; Patino, R.

    2011-01-01

    A simple stoichiometric model is proposed linking the biomass yield to the enthalpy and Gibbs energy changes in chemo-heterotrophic, mixotrophic, and photo-autotrophic microbial growth. A comparison with calorimetric experiments on the algae Chlorella vulgaris and Chlorella sorokiniana confirmed the

  7. Check-list of interstitial polychaetes from intertidal and shallow subtidal soft bottoms of Tenerife, Canary Islands

    OpenAIRE

    Riera, Rodrigo; Núñez, Jorge; Carmen Brito, María del

    2010-01-01

    A check-list of polychaete species from two stations on the south coast of Tenerife (Los Abrigos and Los Cristianos) at two different tidal levels, intertidal and shallow subtidal (3 m depth) is presented. A total of 47 species were collected, the hesionid Microphthalmus pseudoaberrans Campoy & Viéitez, 1982 and the spionids Rhynchospio glutaea (Ehlers, 1897) and Spio filicornis (O.F. Müller, 1776) being the most abundant. With 18 species the family Syllidae is the most diverse, followed b...

  8. An Amoebal Grazer of Cyanobacteria Requires Cobalamin Produced by Heterotrophic Bacteria.

    Science.gov (United States)

    Ma, Amy T; Beld, Joris; Brahamsha, Bianca

    2017-05-15

    Amoebae are unicellular eukaryotes that consume microbial prey through phagocytosis, playing a role in shaping microbial food webs. Many amoebal species can be cultivated axenically in rich media or monoxenically with a single bacterial prey species. Here, we characterize heterolobosean amoeba LPG3, a recent natural isolate, which is unable to grow on unicellular cyanobacteria, its primary food source, in the absence of a heterotrophic bacterium, a Pseudomonas species coisolate. To investigate the molecular basis of this requirement for heterotrophic bacteria, we performed a screen using the defined nonredundant transposon library of Vibrio cholerae , which implicated genes in corrinoid uptake and biosynthesis. Furthermore, cobalamin synthase deletion mutations in V. cholerae and the Pseudomonas species coisolate do not support the growth of amoeba LPG3 on cyanobacteria. While cyanobacteria are robust producers of a corrinoid variant called pseudocobalamin, this variant does not support the growth of amoeba LPG3. Instead, we show that it requires cobalamin that is produced by the Pseudomonas species coisolate. The diversity of eukaryotes utilizing corrinoids is poorly understood, and this amoebal corrinoid auxotroph serves as a model for examining predator-prey interactions and micronutrient transfer in bacterivores underpinning microbial food webs. IMPORTANCE Cyanobacteria are important primary producers in aquatic environments, where they are grazed upon by a variety of phagotrophic protists and, hence, have an impact on nutrient flux at the base of microbial food webs. Here, we characterize amoebal isolate LPG3, which consumes cyanobacteria as its primary food source but also requires heterotrophic bacteria as a source of corrinoid vitamins. Amoeba LPG3 specifically requires the corrinoid variant produced by heterotrophic bacteria and cannot grow on cyanobacteria alone, as they produce a different corrinoid variant. This same corrinoid specificity is also

  9. Pyruvic Oxime Nitrification and Copper and Nickel Resistance by a Cupriavidus pauculus, an Active Heterotrophic Nitrifier-Denitrifier

    Directory of Open Access Journals (Sweden)

    Miguel Ramirez

    2014-01-01

    Full Text Available Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammonium ion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N2 and nitrous oxide (N2O while heterotrophically nitrifying the organic substrate pyruvic oxime [CH3–C(NOH–COOH]. Neither N2 nor N2O were produced. Nucleotide and phylogenetic analyses indicated that the organism is a member of a genus (Cupriavidus known for its resistance to metals and its metabolism of xenobiotics. The microbe (a Cupriavidus pauculus designated as C. pauculus strain UM1 was examined for its ability to perform heterotrophic nitrification in the presence of Cu2+ and Ni2+ and to metabolize the xenobiotic phenol. The bacterium heterotrophically nitrified well when either 1 mM Cu2+ or 0.5 mM Ni2+ was present in either enriched or minimal medium. The organism also used phenol as a sole carbon source in either the presence or absence of 1 mM Cu2+ or 0.5 mM Ni2+. The ability of this isolate to perform a number of different metabolisms, its noteworthy resistance to copper and nickel, and its potential use as a bioremediation agent are discussed.

  10. Circadian cycles in growth and feeding rates of heterotrophic protist plankton

    DEFF Research Database (Denmark)

    Jakobsen, Hans Henrik; Strom, S.L.

    2004-01-01

    Growth and feeding rates of four species of planktonic marine heterotrophic protists showed pronounced diel cycles. In most cases, rates were higher during the day and lower at night. However, for the ciliate Strobilidium sp., growth was highest at night. In another ciliate species, Balanion...... comatum, no day-night difference in growth and feeding rates was found. Maintenance of day-night rate differences during 24-h exposures to continuous darkness demonstrated that most of these protists had circadian cycles. The heterotrophic dinoflagellate Oxyrrhis marina exhibited a clear irradiance...... to culturing in a day: night light cycle in O. marina and found that resetting the circadian cycle in this dinoflagellate temporarily arrested growth and feeding. We suggest that protists use a time-integrated light threshold rather than an instantaneous irradiance to maintain the circadian cell cycle...

  11. Autotrophic and heterotrophic activity in Arctic first-year sea ice

    DEFF Research Database (Denmark)

    Søgaard, Dorte Haubjerg; Kristensen, Morten; Rysgaard, Søren

    2010-01-01

    in plastic bags with subsequent melting and measurements of changes in total O2 concentrations. The standard incubations showed that the annual succession followed a distinctive pattern, with a low, almost balancing heterotrophic and autotrophic activity during February and March. This period was followed...

  12. Draft Genome Sequence of Limnobacter sp. Strain CACIAM 66H1, a Heterotrophic Bacterium Associated with Cyanobacteria.

    Science.gov (United States)

    da Silva, Fábio Daniel Florêncio; Lima, Alex Ranieri Jerônimo; Moraes, Pablo Henrique Gonçalves; Siqueira, Andrei Santos; Dall'Agnol, Leonardo Teixeira; Baraúna, Anna Rafaella Ferreira; Martins, Luisa Carício; Oliveira, Karol Guimarães; de Lima, Clayton Pereira Silva; Nunes, Márcio Roberto Teixeira; Vianez-Júnior, João Lídio Silva Gonçalves; Gonçalves, Evonnildo Costa

    2016-05-19

    Ecological interactions between cyanobacteria and heterotrophic prokaryotes are poorly known. To improve the genomic studies of heterotrophic bacterium-cyanobacterium associations, the draft genome sequence (3.2 Mbp) of Limnobacter sp. strain CACIAM 66H1, found in a nonaxenic culture of Synechococcus sp. (cyanobacteria), is presented here. Copyright © 2016 da Silva et al.

  13. The abundance and diversity of heterotrophic bacteria as a function of harvesting frequency of duckweed (Lemna minor L.) in recirculating aquaculture systems.

    Science.gov (United States)

    Ardiansyah, A; Fotedar, R

    2016-07-01

    Duckweed (Lemna minor L.) is a potential biofilter for nutrient removal and acts as a substrate for heterotrophic bacteria in recirculating aquaculture systems (RAS). Here, we determined the effects of harvesting frequency of duckweed on heterotrophic bacteria in RAS. Twelve independent RAS consisting of fish-rearing tank, biofilter tank and waste-collection tank were used to study the interactions between duckweed harvest frequencies up to 6 days and the composition, abundance and diversity of heterotrophic bacteria. After 36 days, heterotrophic bacteria in the biofilter tank were primarily Gram-negative cocci or ovoid, coccobacilli, Gram-negative bacilli and Gram-positive bacilli. Most bacterial genera were Bacillus and Pseudomonas while the least common was Acinetobacter. Duckweed harvested after every 2 days produced the highest specific growth rates (SGR) and total harvested biomass of duckweed, but harboured less abundant bacteria, whereas 6-day harvests had a higher growth index (GI) of duckweed than 2-day harvests, but caused a poor relationship between SGR and biomass harvest with the abundance and diversity of heterotrophic bacteria. Stronger correlations (R(2)  > 0·65) between duckweed SGR and biomass harvest with the heterotrophic bacteria diversity were observed at 4-day harvest frequency and the control. This study provides significant information on the interaction between the harvest frequency of duckweed and the composition, abundance and diversity of heterotrophic bacteria in recirculating aquaculture systems (RAS). Different harvest frequencies significantly influence the abundance and diversity of heterotrophic bacteria, which in turn may influence the nitrogen uptake efficiency of the system. The research is useful in improving the efficiency of removing nitrogenous metabolites in RAS directly by the duckweed and associated heterotrophic bacteria. © 2016 The Society for Applied Microbiology.

  14. Heterotrophic ammonium removal characteristics of an aerobic heterotrophic nitrifying-denitrifying bacterium, Providencia rettgeri YL

    Institute of Scientific and Technical Information of China (English)

    TAYLOR Shauna M; HE Yiliang; ZHAO Bin; HUANG Jue

    2009-01-01

    Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium (NH4+-N). In order to further analyze its removal ability, several experiments were conducted to identify the growth and ammonium removal response in different carbon to nitrogen (C/N) mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions (C/N 10, 30℃, 120 r/min), YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth. The nitrification products hydroxylamine (NH2OH), nitrite (NO2-) and nitrate (NO3-) as well as the denitrification product, nitrogen gas (N2), were detected under completely aerobic conditions.

  15. Integumentary L-histidine transport in a euryhaline polychaete worm: regulatory roles of calcium and cadmium in the transport event.

    Science.gov (United States)

    Ahearn, H R; Ahearn, G A; Gomme, J

    2000-09-01

    Integumentary uptake of L-[(3)H]histidine by polychaete worms (Nereis succinea) from estuarine waters of Oahu, Hawaii was measured in the presence and absence of calcium and cadmium using a physiological saline that approximated the ion composition of 60 % sea water. In this medium 1 micromol L(-1) cadmium significantly increased (Psystem carrier protein that is regulated by the external divalent cations calcium and cadmium.

  16. Proteomic Changes between Male and Female Worms of the Polychaetous Annelid Neanthes arenaceodentata before and after Spawning

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Ravasi, Timothy; Reish, Donald; Qian, Pei-Yuan

    2013-01-01

    The Neanthes acuminata species complex (Polychaeta) are cosmopolitan in distribution. Neanthes arenaceodentata, complex, has been widely used as toxicological test animal in the marine environment. Method of reproduction is unique in this polychaete complex. Same sexes fight and opposite sexes lie side by side until egg laying. Females lose about 75% of their weight and die after laying eggs. The male, capable of reproducing up to nine times, fertilizes the eggs and incubates the embryos for 3-4 weeks. The objective of this study was to determine if there is any set of proteins that influences this unique pattern of reproduction. Gel-based two-dimensional electrophoresis (2-DE) and gel-free quantitative proteomics methods were used to identify differential protein expression patterns before and after spawning in both male and female N. arenaceodentata. Males showed a higher degree of similarity in protein expression patterns but females showed large changes in phosphoproteme before and after spawning. There was a decrease (about 70%) in the number of detected phosphoproteins in spent females. The proteins involved in muscular development, cell signaling, structure and integrity, and translation were differentially expressed. This study provides proteomic insights of the male and female worms that may serve as a foundation for better understanding of unusual reproductive patterns in polychaete worms. © 2013 Chandramouli et al.

  17. Proteomic Changes between Male and Female Worms of the Polychaetous Annelid Neanthes arenaceodentata before and after Spawning

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2013-08-30

    The Neanthes acuminata species complex (Polychaeta) are cosmopolitan in distribution. Neanthes arenaceodentata, complex, has been widely used as toxicological test animal in the marine environment. Method of reproduction is unique in this polychaete complex. Same sexes fight and opposite sexes lie side by side until egg laying. Females lose about 75% of their weight and die after laying eggs. The male, capable of reproducing up to nine times, fertilizes the eggs and incubates the embryos for 3-4 weeks. The objective of this study was to determine if there is any set of proteins that influences this unique pattern of reproduction. Gel-based two-dimensional electrophoresis (2-DE) and gel-free quantitative proteomics methods were used to identify differential protein expression patterns before and after spawning in both male and female N. arenaceodentata. Males showed a higher degree of similarity in protein expression patterns but females showed large changes in phosphoproteme before and after spawning. There was a decrease (about 70%) in the number of detected phosphoproteins in spent females. The proteins involved in muscular development, cell signaling, structure and integrity, and translation were differentially expressed. This study provides proteomic insights of the male and female worms that may serve as a foundation for better understanding of unusual reproductive patterns in polychaete worms. © 2013 Chandramouli et al.

  18. The moisture response of soil heterotrophic respiration: interaction with soil properties

    DEFF Research Database (Denmark)

    Moyano, F E; Vasilyeva, N; Bouckaert, L

    2012-01-01

    the heterotrophic respiration response to moisture have limited empirical support and introduce an uncertainty of at least 4% in global soil carbon stock predictions by 2100. The necessity of improving the representation of this relationship in models has been highlighted in recent studies. Here we present a data......Soil moisture is of primary importance for predicting the evolution of soil carbon stocks and fluxes, both because it strongly controls organic matter decomposition and because it is predicted to change at global scales in the following decades. However, the soil functions used to model......-driven analysis of soil moisture-respiration relations based on 90 soils. With the use of linear models we show how the relationship between soil heterotrophic respiration and different measures of soil moisture is consistently affected by soil properties. The empirical models derived include main effects...

  19. Proteomic profiling during the pre-competent to competent transition of the biofouling polychaete Hydroides elegans

    KAUST Repository

    Zhang, Yu

    2014-08-22

    The polychaete, Hydroides elegans, is a tube-building worm that is widely distributed in tropical and subtropical seas. It is a dominant fouling species and thus a major target organism in antifouling research. Here, the first high-throughput proteomic profiling of pre-competent and competent larvae of H. elegans is reported with the identification of 1,519 and 1,322 proteins, respectively. These proteins were associated with a variety of biological processes. However, a large proportion was involved in energy metabolism, redox homeostasis, and microtubule-based processes. A comparative analysis revealed 21 proteins that were differentially regulated in larvae approaching competency.

  20. Proteomic profiling during the pre-competent to competent transition of the biofouling polychaete Hydroides elegans

    KAUST Repository

    Zhang, Yu; Sun, Jin; Zhang, Huoming; Chandramouli, Kondethimmanahalli; Xu, Ying; He, Lisheng; Ravasi, Timothy; Qian, Peiyuan

    2014-01-01

    The polychaete, Hydroides elegans, is a tube-building worm that is widely distributed in tropical and subtropical seas. It is a dominant fouling species and thus a major target organism in antifouling research. Here, the first high-throughput proteomic profiling of pre-competent and competent larvae of H. elegans is reported with the identification of 1,519 and 1,322 proteins, respectively. These proteins were associated with a variety of biological processes. However, a large proportion was involved in energy metabolism, redox homeostasis, and microtubule-based processes. A comparative analysis revealed 21 proteins that were differentially regulated in larvae approaching competency.

  1. Proteomic profiling during the pre-competent to competent transition of the biofouling polychaete Hydroides elegans.

    Science.gov (United States)

    Zhang, Yu; Sun, Jin; Zhang, Huoming; Chandramouli, Kondethimmanahalli H; Xu, Ying; He, Li-Sheng; Ravasi, Timothy; Qian, Pei-Yuan

    2014-09-01

    The polychaete, Hydroides elegans, is a tube-building worm that is widely distributed in tropical and subtropical seas. It is a dominant fouling species and thus a major target organism in antifouling research. Here, the first high-throughput proteomic profiling of pre-competent and competent larvae of H. elegans is reported with the identification of 1,519 and 1,322 proteins, respectively. These proteins were associated with a variety of biological processes. However, a large proportion was involved in energy metabolism, redox homeostasis, and microtubule-based processes. A comparative analysis revealed 21 proteins that were differentially regulated in larvae approaching competency.

  2. RARE OCCURRENCE OF HETEROTROPHIC BACTERIA WITH PATHOGENIC POTENTIAL IN POTABLE WATER

    Science.gov (United States)

    Since the discovery of Legionella pneumophila, an opportunistic pathogen that is indigenous to water, microbiologists have speculated that there may be other opportunistic pathogens among the numerous heterotrophic bacteria found in potable water. The USEPA developed a series of...

  3. Characterization of an anthraquinone fluor from the bioluminescent, pelagic polychaete Tomopteris

    Science.gov (United States)

    Francis, Warren R; Powers, Meghan L; Haddock, Steven H D

    2014-01-01

    Tomopteris is a cosmopolitan genus of polychaetes. Many species produce yellow luminescence in the parapodia when stimulated. Yellow bioluminescence is rare in the ocean, and the components of this luminescent reaction have not been identified. Only a brief description, half a century ago, noted fluorescence in the parapodia with a remarkably similar spectrum to the bioluminescence, which suggested that it may be the luciferin or terminal light-emitter. Here, we report the isolation of the fluorescent yellow–orange pigment found in the luminous exudate and in the body of the animals. Liquid chromatography-mass spectrometry revealed the mass to be 270 m/z with a molecular formula of C15H10O5, which ultimately was shown to be aloe-emodin, an anthraquinone previously found in plants. We speculate that aloe-emodin could be a factor for resonant-energy transfer or the oxyluciferin for Tomopteris bioluminescence. PMID:24760626

  4. Polychaete Annelid (segmented worms) Species Composition in the Deep Gulf of Mexico following the Deep Water Horizon (DWH) Oil Spill

    Science.gov (United States)

    QU, F.; Rowe, G.

    2012-12-01

    Sediments 5 to 9 km from the Deep Water Horizon (DWH) Oil Spill site were sampled using a 0.2 m2 box corer 5 months after the event to assess the effects of the oil spill on polychaete annelid (segmented worms) community structure. Numbers of species, abundance, and biodiversity indices were all significantly lower than pre-spill values from similar depths in the eastern Gulf of Mexico (GoM). All of the five dominant species were different. Non-selective deposit feeders and selective deposit feeders were still the most frequent feeding guilds, but their abundances decreased significantly after the event. A large number of carnivorous Sigalionidae may be a response to an accumulation of PAHs on the sediment. Multivariate analyses (CLUSTER and multidimensional scaling (MDS)) illustrate the differences between assemblages near the DWH and those from prior studies in similar deep GoM habitats. In sum, the polychaete populations appeared to be at an early stage of succession in the recovery from the spill or they could be a resident assemblage that is the natural characteristic infauna in or adjacent to natural seeps of fossil hydrocarbons.

  5. Measurement and modeling of polychlorinated biphenyl bioaccumulation from sediment for the marine polychaete neanthes arenaceodentata and response to sorbent amendment

    Science.gov (United States)

    Janssen, E.M.-L.; Croteau, M.-N.; Luoma, S.N.; Luthy, R.G.

    2010-01-01

    Bioaccumulation rates of polychlorinated biphenyls (PCBs) for the marine polychaete Neanthes arenaceodentata were characterized, including PCB uptake rates from water and sediment, and the effect of sorbent amendment to the sediment on PCB bioavailability, organism growth, and lipid content. Physiological parameters were incorporated into a biodynamic model to predict contaminant uptake. The results indicate rapid PCB uptake from contaminated sediment and significant organism growth dilution during time-series exposure studies. PCB uptake from the aqueous phase accounted for less than 3% of the total uptake for this deposit-feeder. Proportional increase of gut residence time and assimilation efficiency as a consequence of the organism's growth was assessed by PCB uptake and a reactor theory model of gut architecture. Pulse-chase feeding and multilabeled stable isotope tracing techniques proved high sediment ingestion rates (i.e., 6?10 times of dry body weight per day) indicating that such deposit-feeders are promising biological indicators for sediment risk assessment. Activated carbon amendment reduced PCB uptake by 95% in laboratory experiments with no observed adverse growth effects on the marine polychaete. Biodynamic modeling explained the observed PCB body burdens for N. arenaceodentata, with and without sorbent amendment. ?? 2009 American Chemical Society.

  6. Putative N2-fixing heterotrophic bacteria associated with dinoflagellate-Cyanobacteria consortia in the low-nitrogen Indian Ocean

    DEFF Research Database (Denmark)

    Farnelid, H.; Tarangkoon, Woraporn; Hansen, Gert

    2010-01-01

    that the symbionts fix gaseous nitrogen (N2). Individual heterotrophic dinoflagellates containing cyanobacterial symbionts were isolated from the open Indian Ocean and off Western Australia, and characterized using light microscopy, transmission electron microscopy (TEM), and nitrogenase (nifH) gene amplification......, cloning, and sequencing. Cyanobacteria, heterotrophic bacteria and eukaryotic algae were recognized as symbionts of the heterotrophic dinoflagellates. nifH gene sequences were obtained from 23 of 37 (62%) specimens of dinoflagellates (Ornithocercus spp. and Amphisolenia spp.). Interestingly, only 2...... specimens contained cyanobacterial nifH sequences, while 21 specimens contained nifH genes related to heterotrophic bacteria. Of the 137 nifH sequences obtained 68% were most similar to Alpha-, Beta-, and Gammaproteobacteria, 8% clustered with anaerobic bacteria, and 5% were related to second alternative...

  7. Heterotrophic bacterial production and metabolic balance during the VAHINE mesocosm experiment in the New Caledonia lagoon

    Science.gov (United States)

    Van Wambeke, France; Pfreundt, Ulrike; Barani, Aude; Berthelot, Hugo; Moutin, Thierry; Rodier, Martine; Hess, Wolfgang R.; Bonnet, Sophie

    2016-06-01

    Studies investigating the fate of diazotrophs through the microbial food web are lacking, although N2 fixation can fuel up to 50 % of new production in some oligotrophic oceans. In particular, the role played by heterotrophic prokaryotes in this transfer is largely unknown. In the frame of the VAHINE (VAriability of vertical and tropHIc transfer of diazotroph derived N in the south wEst Pacific) experiment, three replicate large-volume (˜ 50 m3) mesocosms were deployed for 23 days in the new Caledonia lagoon and were intentionally fertilized on day 4 with dissolved inorganic phosphorus (DIP) to stimulate N2 fixation. We specifically examined relationships between heterotrophic bacterial production (BP) and N2 fixation or primary production, determined bacterial growth efficiency and established carbon budgets. BP was statistically higher during the second phase of the experiment (P2: days 15-23), when chlorophyll biomass started to increase compared to the first phase (P1: days 5-14). Phosphatase alkaline activity increased drastically during the second phase of the experiment, showing adaptations of microbial populations after utilization of the added DIP. Notably, among autotrophs, Synechococcus abundances increased during P2, possibly related to its capacity to assimilate leucine and to produce alkaline phosphatase. Bacterial growth efficiency based on the carbon budget (27-43 %), was notably higher than generally cited for oligotrophic environments and discussed in links with the presence of abundant species of bacteria expressing proteorhodopsin. The main fates of gross primary production (particulate + dissolved) were respiration (67 %) and export through sedimentation (17 %). BP was highly correlated with particulate primary production and chlorophyll biomass during both phases of the experiment but was slightly correlated, and only during P2 phase, with N2 fixation rates. Heterotrophic bacterial production was strongly stimulated after mineral N enrichment

  8. Inference of Interactions in Cyanobacterial-Heterotrophic Co-Cultures via Transcriptome Sequencing

    Energy Technology Data Exchange (ETDEWEB)

    Beliaev, Alex S.; Romine, Margaret F.; Serres, Margaret; Bernstein, Hans C.; Linggi, Bryan E.; Markillie, Lye Meng; Isern, Nancy G.; Chrisler, William B.; Kucek, Leo A.; Hill, Eric A.; Pinchuk, Grigoriy; Bryant, Donald A.; Wiley, H. S.; Fredrickson, Jim K.; Konopka, Allan

    2014-04-29

    We employed deep sequencing technology to identify transcriptional adaptation of the euryhaline unicellular cyanobacterium Synechococcus sp. PCC 7002 and the marine facultative aerobe Shewanella putrefaciens W3-18-1 to growth in a co-culture and infer the effect of carbon flux distributions on photoautotroph-heterotroph interactions. The overall transcriptome response of both organisms to co-cultivation was shaped by their respective physiologies and growth constraints. Carbon limitation resulted in the expansion of metabolic capacities which was manifested through the transcriptional upregulation of transport and catabolic pathways. While growth coupling occurred via lactate oxidation or secretion of photosynthetically fixed carbon, there was evidence of specific metabolic interactions between the two organisms. On one hand, the production and excretion of specific amino acids (methionine and alanine) by the cyanobacterium correlated with the putative downregulation of the corresponding biosynthetic machinery of Shewanella W3-18-1. On the other hand, the broad and consistent decrease of mRNA levels for many Fe-regulated Synechococcus 7002 genes during co-cultivation suggested increased Fe availability as well as more facile and energy-efficient mechanisms for Fe acquisition by the cyanobacterium. Furthermore, evidence pointed at potentially novel interactions between oxygenic photoautotrophs and heterotrophs related to the oxidative stress response as transcriptional patterns suggested that Synechococcus 7002 rather than Shewanella W3-18-1 provided scavenging functions for reactive oxygen species under co-culture conditions. This study provides an initial insight into the complexity of photoautotrophic-heterotrophic interactions and brings new perspectives of their role in the robustness and stability of the association.

  9. Factors governing the pH in a heterotrophic, turbid, tidal estuary

    NARCIS (Netherlands)

    Hofmann, A.F.; Meysman, F.J.R.; Soetaert, K.; Middelburg, J.J.

    2009-01-01

    A method to quantify the influence of kinetically modelled biogeochemical processes on the pH of an ecosystem with time variable acid-base dissociation constants is presented and applied to the heterotrophic, turbid Scheldt estuary (SW Netherlands, N Belgium). Nitrification is identified as the main

  10. Swimming behavior and prey retention of the polychaete larvae Polydora ciliata (Johnston)

    DEFF Research Database (Denmark)

    Hansen, B.W.; Jakobsen, Hans Henrik; Andersen, Anders Peter

    2010-01-01

    in specific feeding rates and the observed increase in the difference between upward and downward swimming speeds with larval size. We estimated a critical larval length above which the buoyancy-corrected weight of the larva exceeds the propulsion force generated by the ciliary swimming apparatus and thus......The behavior of the ubiquitous estuarine planktotrophic spionid polychaete larvae Polydora ciliata was studied. We describe ontogenetic changes in morphology, swimming speed and feeding rates and have developed a simple swimming model using low Reynolds number hydrodynamics. In the model we assumed...... that the ciliary swimming apparatus is primarily composed of the prototroch and secondarily by the telotroch. The model predicted swimming speeds and feeding rates that corresponded well with the measured speeds and rates. Applying empirical data to the model, we were able to explain the profound decrease...

  11. Cellular toxicity and bioaccumulationof silver nanoparticles in the marine polychaete, Nereis diversicolor

    DEFF Research Database (Denmark)

    cong, Yi; Banta, Gary Thomas; Selck, Henriette

    (comet assay) and bioaccumulation as endpoints. Prior to the toxicity experiment, the physical-chemical properties of Ag NPs were fully characterized. The nominal concentrations used in all exposure scenarios were 0, 5, 10, 25, 50 and 100 µg Ag/g dry weight (dw) sediment. Lysosomal membrane stability...... of Nereis coelomocytes, which was measured by neutral red retention time (NRRT), decreased in a concentration-dependent manner in all Ag treatments, indicating increased permeability of lysosomal membranes. Comet assay results showed that Ag was able to cause DNA damage in Nereis coelomocytes regardless......In this study, the toxicities of commercial silver nanoparticles (Ag NPs, 20 and 80 nm) were compared with the toxicities of Ag+ ions in the marine sediment-dwelling polychaete, Nereis diversicolor, after 10 d of sediment exposure, using lysosomal membrane stability (neutral red assay), DNA damage...

  12. The Heterotrophic Bacterial Response During the Meso-scale Southern Ocean Iron Experiment (SOFeX)

    Science.gov (United States)

    Oliver, J. L.; Barber, R. T.; Ducklow, H. W.

    2002-12-01

    Previous meso-scale iron enrichments have demonstrated the stimulatory effect of iron on primary productivity and the accelerated flow of carbon into the surface ocean foodweb. In stratified waters, heterotrophic activity can work against carbon export by remineralizing POC and/or DOC back to CO2, effectively slowing the biological pump. To assess the response of heterotrophic activity to iron enrichment, we measured heterotrophic bacterial production and abundance during the Southern Ocean Iron Experiment (SOFeX). Heterotrophic bacterial processes primarily affect the latter of the two carbon export mechanisms, removal of DOC to the deep ocean. Heterotrophic bacterial production (BP), measured via tritiated thymidine (3H-TdR) and leucine (3H-Leu) incorporation, increased ~40% over the 18-d observation period in iron fertilized waters south of the Polar Front (South Patch). Also, South Patch BP was 61% higher than in the surrounding unfertilized waters. Abundance, measured by flow cytometry (FCM) and acridine orange direct counts (AODC), also increased in the South Patch from 3 to 5 x 108 cells liter-1, a 70% increase. Bacterial biomass increased from ~3.6 to 6.3 μg C liter-1, a clear indication that production rates exceeded removal rates (bactivory, viral lysis) over the course of 18 days. Biomass within the fertilized patch was 11% higher than in surrounding unfertilized waters reflecting a similar trend. This pattern is in contrast to SOIREE where no accumulation of biomass was observed. High DNA-containing (HDNA) cells detected by FCM also increased over time in iron fertilized waters from 20% to 46% relative to the total population suggesting an active subpopulation of cells that were growing faster than the removal rates. In iron fertilized waters north of the Polar Front (North Patch), BP and abundance were ~90% and 80% higher, respectively, than in unfertilized waters. Our results suggest an active bacterial population that responded to iron fertilization

  13. Roots affect the response of heterotrophic soil respiration to temperature in tussock grass microcosms.

    Science.gov (United States)

    Graham, Scott L; Millard, Peter; Hunt, John E; Rogers, Graeme N D; Whitehead, David

    2012-07-01

    While the temperature response of soil respiration (R(S)) has been well studied, the partitioning of heterotrophic respiration (R(H)) by soil microbes from autotrophic respiration (R(A)) by roots, known to have distinct temperature sensitivities, has been problematic. Further complexity stems from the presence of roots affecting R(H), the rhizosphere priming effect. In this study the short-term temperature responses of R(A) and R(H) in relation to rhizosphere priming are investigated. Temperature responses of R(A), R(H) and rhizosphere priming were assessed in microcosms of Poa cita using a natural abundance δ(13)C discrimination approach. The temperature response of R(S) was found to be regulated primarily by R(A), which accounted for 70 % of total soil respiration. Heterotrophic respiration was less sensitive to temperature in the presence of plant roots, resulting in negative priming effects with increasing temperature. The results emphasize the importance of roots in regulating the temperature response of R(S), and a framework is presented for further investigation into temperature effects on heterotrophic respiration and rhizosphere priming, which could be applied to other soil and vegetation types to improve models of soil carbon turnover.

  14. Phosphoproteome analysis during larval development and metamorphosis in the spionid polychaete Pseudopolydora vexillosa

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Mok, Flora SY; Wang, Hao; Qian, Pei-Yuan

    2011-01-01

    Background: The metamorphosis of the spionid polychaete Pseudopolydora vexillosa includes spontaneous settlement onto soft-bottom habitats and morphogenesis that can be completed in a very short time. A previous study on the total changes to the proteome during the various developmental stages of P. vexillosa suggested that little or no de novo protein synthesis occurs during metamorphosis. In this study, we used multicolor fluorescence detection of proteins in 2-D gels for differential analysis of proteins and phosphoproteins to reveal the dynamics of post-translational modification proteins in this species. A combination of affinity chromatography, 2D-PAGE, and mass spectrometry was used to identify the phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles. Results: We reproducibly detected 210, 492, and 172 phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles, respectively. The highest percentage of phosphorylation was observed during the competent larval stage. About 64 stage-specific phosphoprotein spots were detected in the competent stage, and 32 phosphoproteins were found to be significantly differentially expressed in the three stages. We identified 38 phosphoproteins, 10 of which were differentially expressed during metamorphosis. These phosphoproteins belonged to six categories of biological processes: (1) development, (2) cell differentiation and integrity, (3) transcription and translation, (4) metabolism, (5) protein-protein interaction and proteolysis, and (6) receptors and enzymes. Conclusion: This is the first study to report changes in phosphoprotein expression patterns during the metamorphosis of the marine polychaete P. vexillosa. The higher degree of phosphorylation during the process of attaining competence to settle and metamorphose may be due to fast morphological transitions regulated by various mechanisms. Our data are consistent with previous studies showing a

  15. Phosphoproteome analysis during larval development and metamorphosis in the spionid polychaete Pseudopolydora vexillosa

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2011-05-25

    Background: The metamorphosis of the spionid polychaete Pseudopolydora vexillosa includes spontaneous settlement onto soft-bottom habitats and morphogenesis that can be completed in a very short time. A previous study on the total changes to the proteome during the various developmental stages of P. vexillosa suggested that little or no de novo protein synthesis occurs during metamorphosis. In this study, we used multicolor fluorescence detection of proteins in 2-D gels for differential analysis of proteins and phosphoproteins to reveal the dynamics of post-translational modification proteins in this species. A combination of affinity chromatography, 2D-PAGE, and mass spectrometry was used to identify the phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles. Results: We reproducibly detected 210, 492, and 172 phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles, respectively. The highest percentage of phosphorylation was observed during the competent larval stage. About 64 stage-specific phosphoprotein spots were detected in the competent stage, and 32 phosphoproteins were found to be significantly differentially expressed in the three stages. We identified 38 phosphoproteins, 10 of which were differentially expressed during metamorphosis. These phosphoproteins belonged to six categories of biological processes: (1) development, (2) cell differentiation and integrity, (3) transcription and translation, (4) metabolism, (5) protein-protein interaction and proteolysis, and (6) receptors and enzymes. Conclusion: This is the first study to report changes in phosphoprotein expression patterns during the metamorphosis of the marine polychaete P. vexillosa. The higher degree of phosphorylation during the process of attaining competence to settle and metamorphose may be due to fast morphological transitions regulated by various mechanisms. Our data are consistent with previous studies showing a

  16. Spatial Variability of Cyanobacteria and Heterotrophic Bacteria in Lake Taihu (China).

    Science.gov (United States)

    Qian, Haifeng; Lu, Tao; Song, Hao; Lavoie, Michel; Xu, Jiahui; Fan, Xiaoji; Pan, Xiangliang

    2017-09-01

    Cyanobacterial blooms frequently occur in Lake Taihu (China), but the intertwined relationships between biotic and abiotic factors modulating the frequency and duration of the blooms remain enigmatic. To better understand the relationships between the key abiotic and biotic factors and cyanobacterial blooms, we measured the abundance and diversity of prokaryotic organisms by high-throughput sequencing, the abundance of key genes involved in microcystin production and nitrogen fixation or loss as well as several physicochemical parameters at several stations in Lake Taihu during a cyanobacterial bloom of Microcystis sp.. Measurements of the copy number of denitrification-related genes and 16S rRNA analyses show that denitrification potential and denitrifying bacteria abundance increased in concert with non-diazotrophic cyanobacteria (Microcystis sp.), suggesting limited competition between cyanobacteria and heterotrophic denitrifiers for nutrients, although potential bacteria-mediated N loss may hamper Microcystis growth. The present study provides insight into the importance of different abiotic and biotic factors in controlling cyanobacteria and heterotrophic bacteria spatial variability in Lake Taihu.

  17. Novel insight into the role of heterotrophic dinoflagellates in the fate of crude oil in the sea

    DEFF Research Database (Denmark)

    Almeda, Rodrigo; Connelly, Tara L.; Buskey, Edward J.

    2014-01-01

    Although planktonic protozoans are likely to interact with dispersed crude oil after a spill, protozoan-mediated processes affecting crude oil pollution in the sea are still not well known. Here, we present the first evidence of ingestion and defecation of physically or chemically dispersed crude...... to 0.37 mu g-oil mg-C-dino (-1) d(-1), which could represent similar to 17% to 100% of dispersed oil in surface waters when heterotrophic dinoflagellates are abundant or bloom. Egestion of faecal pellets containing crude oil by heterotrophic dinoflagellates could contribute to the sinking and flux...... of toxic petroleum hydrocarbons in coastal waters. Our study indicates that crude oil ingestion by heterotrophic dinoflagellates is a noteworthy route by which petroleum enters marine food webs and a previously overlooked biological process influencing the fate of crude oil in the sea after spills....

  18. Isolation and life cycle characterization of lytic viruses infecting heterotrophic bacteria and cyanobacteria

    DEFF Research Database (Denmark)

    Middelboe, Mathias; Chan, Amy; Bertelsen, Sif Koldborg

    2010-01-01

    Basic knowledge on viruses infecting heterotrophic bacteria and cyanobacteria is key to future progress in understanding the role of viruses in aquatic systems and the influence of virus–host interactions on microbial mortality, biogeochemical cycles, and genetic exchange. Such studies require......, and discusses the applications and limitations of different isolation procedures. Most work on phage isolation has been carried out with aerobic heterotrophic bacteria and cyanobacteria, culturable both on agar plates and in enriched liquid cultures. The procedures presented here are limited to lytic viruses...... infecting such hosts. In addition to the isolation procedures, methods for life cycle characterization (one-step growth experiments) of bacteriophages and cyanophages are described. Finally, limitations and drawbacks of the proposed methods are assessed and discussed...

  19. Studies on mangrove swamps of Goa 1. Heterotrophic bacterial flora from mangrove swamps

    Digital Repository Service at National Institute of Oceanography (India)

    Matondkar, S.G.P; Mathani, S; Mavinkurve, S

    Heterotrophic bacterial flora from the mangrove swamps of Goa consisted of physiologically active organisms exhibiting cellulolytic, pectinolytic, amylolytic, proteolytic and H2S forming activities, throughout the year. Coryneform and Bacillus were...

  20. Effects of copper on the sabellid polychaete, Eudistylia vancouveri. II. copper accumulation and tissue injury in the branchial crown

    Energy Technology Data Exchange (ETDEWEB)

    Young, J S [Pacific Northwest Lab., Sequim, WA; Adee, R R; Piscopo, I; Buschbom, R L

    1981-01-01

    Copper in seawater caused injury to the radioles (gills) of the sabellid polychaete, Eudistylia vancouveri. Light and electron microscopy showed the loss of cellular adhesion and the structural derangement that lead to cell necrosis and death. The progression of injury was related to the uptake of copper into the tissues. Copper was found by X-ray microanalysis to be localized subcellularly in membrane-bound vesicles that are similar to lysosomes. Cell breakdown may result from lysosmal labilization.

  1. Response of benthic opportunistic polychaetes and amphipods index to different perturbations in coastal oligotrophic areas (Canary archipelago, North East Atlantic Ocean)

    OpenAIRE

    Riera, Rodrigo; de-la-Ossa-Carretero, Jose Antonio

    2014-01-01

    Oligotrophic areas harbour low macrofaunal abundance and patchy distribution. In these areas it is necessary to test the reliability of biological indicators, especially those based on taxonomic sufficiency where the level of identification is balanced against the need for ecological information and could affect the efficiency of bioindicators. The BOPA (benthic opportunistic polychaetes and amphipods) index was applied in five coastal areas subjected to different perturbations (aquaculture, ...

  2. Trophic interactions among the heterotrophic components of plankton in man-made peat pools

    Directory of Open Access Journals (Sweden)

    Michał Niedźwiecki

    2017-03-01

    Full Text Available Man-made peat pools are permanent freshwater habitats developed due to non-commercial man-made peat extraction. Yet, they have not been widely surveyed in terms of ecosystem functioning, mainly regarding the complexity of heterotrophic components of the plankton. In this study we analysed distribution and trophic interrelations among heterotrophic plankton in man-made peat pools located in different types of peatbogs. We found that peat pools showed extreme differences in environmental conditions that occurred to be important drivers of distribution of microplankton and metazooplankton. Abundance of bacteria and protozoa showed significant differences, whereas metazooplankton was less differentiated in density among peat pools. In all peat pools stress-tolerant species of protozoa and metazoa were dominant. In each peat pool five trophic functional groups were distinguished. The abundance of lower functional trophic groups (bacteria, heterotrophic nanoflagellates (HNF and ciliates feeding on bacteria and HNF was weakly influenced by environmental drivers and was highly stable in all peat pool types. Higher functional trophic groups (naupli, omnivorous and carnivorous ciliates, cladocerans, adult copepods and copepodites were strongly influenced by environmental variables and exhibited lower stability. Our study contributes to comprehensive knowledge of the functioning of peat bogs, as our results have shown that peat pools are characterized by high stability of the lowest trophic levels, which can be crucial for energy transfer and carbon flux through food webs.

  3. Uptake, Accumulation and Toxicity of Silver Nanoparticle in Autotrophic Plants, and Heterotrophic Microbes: A Concentric Review

    Science.gov (United States)

    Tripathi, Durgesh K.; Tripathi, Ashutosh; Shweta; Singh, Swati; Singh, Yashwant; Vishwakarma, Kanchan; Yadav, Gaurav; Sharma, Shivesh; Singh, Vivek K.; Mishra, Rohit K.; Upadhyay, R. G.; Dubey, Nawal K.; Lee, Yonghoon; Chauhan, Devendra K.

    2017-01-01

    Nanotechnology is a cutting-edge field of science with the potential to revolutionize today’s technological advances including industrial applications. It is being utilized for the welfare of mankind; but at the same time, the unprecedented use and uncontrolled release of nanomaterials into the environment poses enormous threat to living organisms. Silver nanoparticles (AgNPs) are used in several industries and its continuous release may hamper many physiological and biochemical processes in the living organisms including autotrophs and heterotrophs. The present review gives a concentric know-how of the effects of AgNPs on the lower and higher autotrophic plants as well as on heterotrophic microbes so as to have better understanding of the differences in effects among these two groups. It also focuses on the mechanism of uptake, translocation, accumulation in the plants and microbes, and resulting toxicity as well as tolerance mechanisms by which these microorganisms are able to survive and reduce the effects of AgNPs. This review differentiates the impact of silver nanoparticles at various levels between autotrophs and heterotrophs and signifies the prevailing tolerance mechanisms. With this background, a comprehensive idea can be made with respect to the influence of AgNPs on lower and higher autotrophic plants together with heterotrophic microbes and new insights can be generated for the researchers to understand the toxicity and tolerance mechanisms of AgNPs in plants and microbes. PMID:28184215

  4. Occurrence of heterotrophic and coliform bacteria in liquid hand soaps from bulk refillable dispensers in public facilities.

    Science.gov (United States)

    Chattman, Marisa; Gerba, Sheri L; Maxwell, Charles P

    2011-03-01

    The goal of the study discussed in this article was to determine the occurrence of heterotrophic and coliform bacteria in liquid soap from bulk refillable dispensers, obtained from restrooms in a variety of public facilities. A total of 541 samples was collected from five U.S. cities. Liquid soap from dispensers in public areas was found to contain heterotrophic and coliform bacterial numbers averaging more than 106 CFU/mL in 24.8% of the dispensers.

  5. Can heterotrophic uptake of dissolved organic carbon and zooplankton mitigate carbon budget deficits in annually bleached corals?

    Science.gov (United States)

    Levas, Stephen; Grottoli, Andréa G.; Schoepf, Verena; Aschaffenburg, Matthew; Baumann, Justin; Bauer, James E.; Warner, Mark E.

    2016-06-01

    Annual coral bleaching events due to increasing sea surface temperatures are predicted to occur globally by the mid-century and as early as 2025 in the Caribbean, and severely impact coral reefs. We hypothesize that heterotrophic carbon (C) in the form of zooplankton and dissolved organic carbon (DOC) is a significant source of C to bleached corals. Thus, the ability to utilize multiple pools of fixed carbon and/or increase the amount of fixed carbon acquired from one or more pools of fixed carbon (defined here as heterotrophic plasticity) could underlie coral acclimatization and persistence under future ocean-warming scenarios. Here, three species of Caribbean coral— Porites divaricata, P. astreoides, and Orbicella faveolata—were experimentally bleached for 2.5 weeks in two successive years and allowed to recover in the field. Zooplankton feeding was assessed after single and repeat bleaching, while DOC fluxes and the contribution of DOC to the total C budget were determined after single bleaching, 11 months on the reef, and repeat bleaching. Zooplankton was a large C source for P. astreoides, but only following single bleaching. DOC was a source of C for single-bleached corals and accounted for 11-36 % of daily metabolic demand (CHARDOC), but represented a net loss of C in repeat-bleached corals. In repeat-bleached corals, DOC loss exacerbated the negative C budgets in all three species. Thus, the capacity for heterotrophic plasticity in corals is compromised under annual bleaching, and heterotrophic uptake of DOC and zooplankton does not mitigate C budget deficits in annually bleached corals. Overall, these findings suggest that some Caribbean corals may be more susceptible to repeat bleaching than to single bleaching due to a lack of heterotrophic plasticity, and coral persistence under increasing bleaching frequency may ultimately depend on other factors such as energy reserves and symbiont shuffling.

  6. Molasses as C source for heterotrophic bacteria production on solid fish waste

    NARCIS (Netherlands)

    Schneider, O.; Sereti, V.; Eding, E.H.; Verreth, J.A.J.

    2006-01-01

    The drumfilter effluent from a recirculation aquaculture system (RAS) can be used as substrate for heterotrophic bacteria production. These bacteria can be reused as aquatic feed. In RAS drumfilter effluents are organic carbon deficient for bacteria production. This is due to nitrogen accumulation

  7. Polychaete richness and abundance enhanced in anthropogenically modified estuaries despite high concentrations of toxic contaminants.

    Directory of Open Access Journals (Sweden)

    Katherine A Dafforn

    Full Text Available Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a 'positive' response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching. Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively 'pristine' estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic

  8. Acidophilic algae isolated from mine-impacted environments and their roles in sustaining heterotrophic acidophiles

    Directory of Open Access Journals (Sweden)

    David Barrie Johnson

    2012-09-01

    Full Text Available Two acidophilic algae, identified as strains of Chlorella protothecoides var. acidicola and Euglena mutabilis, were isolated in pure culture from abandoned copper mines in Spain and Wales and grown in pH- and temperature-controlled bioreactors. The Chlorella isolate grew optimally at pH 2.5 and 30 ˚C, with a corresponding culture doubling time of 9 hours. The isolates displayed similar tolerance (10-50 mM to four transition metals tested. Growth of the algae in liquid media was paralleled with increasing concentrations of dissolved organic carbon (DOC. Glycolic acid was identified as a significant component (12- 14% of total DOC. Protracted incubation resulted in concentrations of glycolic acid declining in both cases, and glycolic acid added to a culture of Chlorella incubated in the dark was taken up by the alga (~100% within three days. Two monosaccharides were identified in cell-free liquors of each algal isolate: fructose and glucose (Chlorella, and mannitol and glucose (Euglena. These were rapidly metabolised by acidophilic heterotrophic bacteria (Acidiphilium and Acidobacterium spp. though only fructose was utilised by the more fastidious heterotroph Acidocella aromatica. The significance of algae in promoting the growth of iron- (and sulfate- reducing heterotrophic acidophiles that are important in remediating mine-impacted waters is discussed.

  9. Effects of intense agricultural practices on heterotrophic processes in streams

    Energy Technology Data Exchange (ETDEWEB)

    Piscart, Christophe [Universite Claude Bernard Lyon 1 - Laboratoire d' Ecologie des Hydrosystemes Fluviaux - UMR CNRS 5023 - Campus Doua, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Universite de Rennes 1 - UMR CNRS ECOBIO 6553 - Campus Beaulieu, 263 Av. du General Leclerc, 35042 Rennes Cedex (France)], E-mail: christophe.piscart@univ-lyon1.fr; Genoel, Romuald [Universite de Rennes 1 - UMR CNRS ECOBIO 6553 - Campus Beaulieu, 263 Av. du General Leclerc, 35042 Rennes Cedex (France); Doledec, Sylvain [Universite Claude Bernard Lyon 1 - Laboratoire d' Ecologie des Hydrosystemes Fluviaux - UMR CNRS 5023 - Campus Doua, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Chauvet, Eric [Universite Paul Sabatier de Toulouse - Laboratoire EcoLab - UMR CNRS 5245, 29 rue Jeanne Marvig, 31055 Toulouse Cedex 4 (France); Marmonier, Pierre [Universite Claude Bernard Lyon 1 - Laboratoire d' Ecologie des Hydrosystemes Fluviaux - UMR CNRS 5023 - Campus Doua, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Universite de Rennes 1 - UMR CNRS ECOBIO 6553 - Campus Beaulieu, 263 Av. du General Leclerc, 35042 Rennes Cedex (France)

    2009-03-15

    In developed countries, changes in agriculture practices have greatly accelerated the degradation of the landscape and the functioning of adjacent aquatic ecosystems. Such alteration can in turn impair the services provided by aquatic ecosystems, namely the decomposition of organic matter, a key process in most small streams. To study this alteration, we recorded three measures of heterotrophic activity corresponding to microbial hydrolasic activity (FDA hydrolysis) and leaf litter breakdown rates with (k{sub c}) and without invertebrates (k{sub f}) along a gradient of contrasted agricultural pressures. Hydrolasic activity and k{sub f} reflect local/microhabitat conditions (i.e. nutrient concentrations and organic matter content of the sediment) but not land use while k{sub c} reflects land-use conditions. k{sub c}, which is positively correlated with the biomass of Gammaridae, significantly decreased with increasing agricultural pressure, contrary to the taxonomic richness and biomass of Trichoptera and Plecoptera. Gammaridae may thus be considered a key species for organic matter recycling in agriculture-impacted streams. - This study highlights the consequences of intensive agricultural practices on heterotrophic processes in streams along a strong gradient of perturbation.

  10. Depth Dependent Relationships between Temperature and Ocean Heterotrophic Prokaryotic Production

    KAUST Repository

    Lønborg, Christian

    2016-06-07

    Marine prokaryotes play a key role in cycling of organic matter and nutrients in the ocean. Using a unique dataset (>14,500 samples), we applied a space-for-time substitution analysis to assess the temperature dependence of prokaryotic heterotrophic production (PHP) in epi- (0-200 m), meso- (201-1000 m) and bathypelagic waters (1001-4000 m) of the global ocean. Here, we show that the temperature dependence of PHP is fundamentally different between these major oceanic depth layers, with an estimated ecosystem-level activation energy (E) of 36 ± 7 kJ mol for the epipelagic, 72 ± 15 kJ mol for the mesopelagic and 274 ± 65 kJ mol for the bathypelagic realm. We suggest that the increasing temperature dependence with depth is related to the parallel vertical gradient in the proportion of recalcitrant organic compounds. These Ea predict an increased PHP of about 5, 12, and 55% in the epi-, meso-, and bathypelagic ocean, respectively, in response to a water temperature increase by 1°C. Hence, there is indication that a major thus far underestimated feedback mechanism exists between future bathypelagic ocean warming and heterotrophic prokaryotic activity.

  11. Depth Dependent Relationships between Temperature and Ocean Heterotrophic Prokaryotic Production

    KAUST Repository

    Lø nborg, Christian; Cuevas, L. Antonio; Reinthaler, Thomas; Herndl, Gerhard J.; Gasol, Josep M.; Moran, Xose Anxelu G.; Bates, Nicholas R.; á lvarez-Salgado, Xosé A.

    2016-01-01

    Marine prokaryotes play a key role in cycling of organic matter and nutrients in the ocean. Using a unique dataset (>14,500 samples), we applied a space-for-time substitution analysis to assess the temperature dependence of prokaryotic heterotrophic production (PHP) in epi- (0-200 m), meso- (201-1000 m) and bathypelagic waters (1001-4000 m) of the global ocean. Here, we show that the temperature dependence of PHP is fundamentally different between these major oceanic depth layers, with an estimated ecosystem-level activation energy (E) of 36 ± 7 kJ mol for the epipelagic, 72 ± 15 kJ mol for the mesopelagic and 274 ± 65 kJ mol for the bathypelagic realm. We suggest that the increasing temperature dependence with depth is related to the parallel vertical gradient in the proportion of recalcitrant organic compounds. These Ea predict an increased PHP of about 5, 12, and 55% in the epi-, meso-, and bathypelagic ocean, respectively, in response to a water temperature increase by 1°C. Hence, there is indication that a major thus far underestimated feedback mechanism exists between future bathypelagic ocean warming and heterotrophic prokaryotic activity.

  12. Bacterial abundance, communities and heterotrophic activities in the coastal waters off Tamil Nadu

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Raghukumar, C.; Sheelu, G.; Chandramohan, D.

    Culturable aerobic heterotrophic bacterial (CAHB) numbers, total direct counts (TDC), bacterial generic composition and uptake of labelled glucose by natural microbial assemblages were studied from a few selected coastal sites off Tamil Nadu. A high...

  13. Membrane biofouling in a wastewater nitrification reactor: microbial succession from autotrophic colonization to heterotrophic domination

    KAUST Repository

    Lu, Huijie

    2015-10-22

    Membrane biofouling is a complex process that involves bacterial adhesion, extracellular polymeric substances (EPS) excretion and utilization, and species interactions. To obtain a better understanding of the microbial ecology of biofouling process, this study conducted rigorous, time-course analyses on the structure, EPS and microbial composition of the fouling layer developed on ultrafiltration membranes in a nitrification bioreactor. During a 14-day fouling event, three phases were determined according to the flux decline and microbial succession patterns. In Phase I (0-2 days), small sludge flocs in the bulk liquid were selectively attached on membrane surfaces, leading to the formation of similar EPS and microbial community composition as the early biofilms. Dominant populations in small flocs, e.g., Nitrosomonas, Nitrobacter, and Acinetobacter spp., were also the major initial colonizers on membranes. In Phase II (2-4 d), fouling layer structure, EPS composition, and bacterial community went through significant changes. Initial colonizers were replaced by fast-growing and metabolically versatile heterotrophs (e.g., unclassified Sphingobacteria). The declining EPS polysaccharide to protein (PS:PN) ratios could be correlated well with the increase in microbial community diversity. In Phase III (5-14 d), heterotrophs comprised over 90% of the community, whereas biofilm structure and EPS composition remained relatively stable. In all phases, AOB and NOB were constantly found within the top 40% of the fouling layer, with the maximum concentrations around 15% from the top. The overall microbial succession pattern from autotrophic colonization to heterotrophic domination implied that MBR biofouling could be alleviated by forming larger bacterial flocs in bioreactor suspension (reducing autotrophic colonization), and by designing more specific cleaning procedures targeting dominant heterotrophs during typical filtration cycles.

  14. The influence of the organophosphorus insecticides acephate and parathion upon the heterotrophic bacteria of two freshwater ecosystems

    International Nuclear Information System (INIS)

    Albright, L.J.; Geen, G.H.; Gasith, A.; Mozel, Y.; Perry, A.S.

    1983-01-01

    The effect of acephate and parathion on the heterotrophic bacteria of freshwater ecosystems was studied in a dystrophic west coast Canadian lake and in an eutrophic Israeli fish pond. The limnocorrals were treated with 1-25 ppm of acephate and 30-40 ppb of parathion respectively. Bacterial populations, glucose heterotrophic activities and bacterial and algal productivities were studied using 3 H and 14 C radioisotopes. It is concluded that the two ecosystems are not extensively affected by the pesticide concentrations used

  15. Simultaneous heterotrophic nitrification and aerobic denitrification by the marine origin bacterium Pseudomonas sp. ADN-42.

    Science.gov (United States)

    Jin, Ruofei; Liu, Tianqi; Liu, Guangfei; Zhou, Jiti; Huang, Jianyu; Wang, Aijie

    2015-02-01

    Recent research has highlighted the existence of some bacteria that are capable of performing heterotrophic nitrification and have a phenomenal ability to denitrify their nitrification products under aerobic conditions. A high-salinity-tolerant strain ADN-42 was isolated from Hymeniacidon perleve and found to display high heterotrophic ammonium removal capability. This strain was identified as Pseudomonas sp. via 16S rRNA gene sequence analysis. Gene cloning and sequencing analysis indicated that the bacterial genome contains N2O reductase function (nosZ) gene. NH3-N removal rate of ADN-42 was very high. And the highest removal rate was 6.52 mg/L · h in the presence of 40 g/L NaCl. Under the condition of pure oxygen (DO >8 mg/L), NH3-N removal efficiency was 56.9 %. Moreover, 38.4 % of oxygen remained in the upper gas space during 72 h without greenhouse gas N2O production. Keeping continuous and low level of dissolved oxygen (DO <3 mg/L) was helpful for better denitrification performance. All these results indicated that the strain has heterotrophic nitrification and aerobic denitrification abilities, which guarantee future application in wastewater treatment.

  16. Separating Autotrophic and Heterotrophic Respiration in Streams and the Importance for Carbon Cycling: a Preliminary Study

    Science.gov (United States)

    Bozeman, M.; Raymond, P.

    2005-05-01

    Autotrophic and heterotrophic organisms confer different effects on nutrient cycling, especially on carbon (C). In stream ecosystems, net ecosystem production determines the amount and form of C exported; however any transformation due to different respiratory (R) mechanisms are not separated. These mechanisms highly influence the form and lability of the C transported. To understand the current state of knowledge and estimate the importance of autotrophic versus heterotrophic R, we obtained a range of respiratory rates from the literature and modeled effects of different balances of rates on bulk dissolved inorganic and organic C chemistry. Preliminary results show that a wide range of estimates of autotrophic R exist and that these can effect bulk properties of exported C. While specific effects are highly dependent upon physical structure of the study watershed, we offer that separating R mechanisms provides further insight into ecosystem C cycling. We also propose a method to measure autotrophic and heterotrophic R at the ecosystem scale and obtain watershed-level estimates of the importance of these processes on C cycling.

  17. Micro-electrolysis/retinervus luffae-based simultaneous autotrophic and heterotrophic denitrification for low C/N wastewater treatment.

    Science.gov (United States)

    Li, Jinlong; Li, Desheng; Cui, Yuwei; Xing, Wei; Deng, Shihai

    2017-07-01

    Nitrogen bioremediation in organic insufficient wastewater generally requires an extra carbon source. In this study, nitrate-contaminated wastewater was treated effectively through simultaneous autotrophic and heterotrophic denitrification based on micro-electrolysis carriers (MECs) and retinervus luffae fructus (RLF), respectively. The average nitrate and total nitrogen removal rates reached 96.3 and 94.0% in the MECs/RLF-based autotrophic and heterotrophic denitrification (MRAHD) system without ammonia and nitrite accumulation. The performance of MRAHD was better than that of MEC-based autotrophic denitrification for the wastewater treatment with low carbon nitrogen (COD/N) ratio. Real-time quantitative polymerase chain reaction (qPCR) revealed that the relative abundance of nirS-type denitrifiers attached to MECs (4.9%) and RLF (5.0%) was similar. Illumina sequencing suggested that the dominant genera were Thiobacillus (7.0%) and Denitratisoma (5.7%), which attached to MECs and RLF, respectively. Sulfuritalea was discovered as the dominant genus in the middle of the reactor. The synergistic interaction between autotrophic and heterotrophic denitrifiers played a vital role in the mixotrophic substrate environment.

  18. Treatment of cattle-slaughterhouse wastewater and the reuse of sludge for biodiesel production by microalgal heterotrophic bioreactors

    Directory of Open Access Journals (Sweden)

    Mariana Manzoni Maroneze

    2014-12-01

    Full Text Available Microalgal heterotrophic bioreactors are a potential technological development that can convert organic matter, nitrogen and phosphorus of wastewaters into a biomass suitable for energy production. The aim of this work was to evaluate the performance of microalgal heterotrophic bioreactors in the secondary treatment of cattle-slaughterhouse wastewater and the reuse of microalgal sludge for biodiesel production. The experiments were performed in a bubble column bioreactor using the microalgae Phormidium sp. Heterotrophic microalgal bioreactors removed 90 % of the chemical oxygen demand, 57 % of total nitrogen and 52 % of total phosphorus. Substantial microalgal sludge is produced in the process (substrate yield coefficient of 0.43 mg sludge mg chemical oxygen demand−¹, resulting in a biomass with high potential for producing biodiesel (ester content of more than 99 %, cetane number of 55, iodine value of 73.5 g iodine 100 g−¹, unsaturation degree of ~75 % and a cold filter plugging point of 5 ºC.

  19. Bacterial biomass and heterotrophic potential in the waters of the Chesapeake Bay plume and contiguous continental shelf

    Science.gov (United States)

    Kator, H. I.; Zubkoff, P. L.

    1981-01-01

    Seasonal baseline data on bacterial biomass and heterotrophic uptake in the Chesapeake Bay plume and contiguous Atlantic Ocean shelf waters are discussed. Viable count bacterial numbers in surface water samples collected during June 1980 ranged from a maximum of 190,000 MPN (most probable number)/ml at the Bay mouth to a minimum of 7900 MPN/ml offshore. Similarly, direct count densities ranged from 1,800,000 BU (bacterial units)/ml to 24,000 BU/ml. Heterotrophic potential (V max) was largest at the Bay mouth and lowest offshore. Biomass and V max values usually decreased with depth although subsurface maxima were occasionally observed at inshore stations. Correlation of biomass and heterotrophic potential data with selected hydrographic variables was determind with a nonparametric statistic. Results indicate viable counts are positively and significantly correlated with total chlorophyll, temperature, direct count and V max during June 1980; significant negative correlations are obtained with salinity and depth. Calculations of bacterial standing crop are discussed.

  20. The Effect of Aluminium on Antibacterial Properties and the Content of Some Fatty Acids in Microalgae, Chlorella vulgaris Beijernick, under Heterotrophic and Autotrophic Conditions

    Directory of Open Access Journals (Sweden)

    Hossein Abbaspour

    2017-01-01

    Full Text Available Microalgae are a group of organisms, which have a significant potential for industrial applications. These algae contain large amounts of lipids compounds that are beneficial to health, have antibacterial properties, and their extracted oil can be used for biofuel. In this study, microalgae Chlorella vulgaris Beijernick was grown in the culture medium BG-11 containing aluminium (AlCl3 under autotrophic and heterotrophic conditions. In each case, survival and growth, dry weight, internal aluminium content of the sample, antibacterial properties, the content of fatty acids accumulated in the algae and secreted into the culture medium in the logarithmic growth phase were studied. Aluminium significantly increased (P < .05 growth and dry weight in autotrophic treatment compared to the heterotrophic one. Most antibacterial properties were observed in methanol extracts of heterotrophic treatments containing 0.05% glucose. Aluminium also decreased fatty acids accumulation in the algae and increased fatty acids excretion into the culture medium in heterotrophic treatment compared to the autotrophic treatment. Survival of the sample was maintained in heterotrophic conditions and showed growth without lag phase, which is indicative of rapid acclimation of organisms in heterotrophic conditions. It seems that the mentioned characteristics make the single-celled green algae Chlorella vulgaris more efficient in different ways.

  1. Unicellular cyanobacteria synechocystis accommodate heterotrophic bacteria with varied enzymatic and metal resistance properties

    Digital Repository Service at National Institute of Oceanography (India)

    Anas, A.; Sageer, S.; Jasmin, C.; Vijayan, V.; Pavanan, P.; Athiyanathil, S.; Nair, S.

    unicellular cyanobacterium Synechocystis sp. that came from a heavy metal contaminated region of Cochin estuary, southwest coast of India. Based on 16S rRNA gene sequence similarities, the heterotrophic bacteria were grouped into three phyla: namely...

  2. Population and reproductive dynamics of the polychaete Pygospio elegans in a boreal estuary complex

    DEFF Research Database (Denmark)

    Thonig, Anne; Knott, K Emily; Kesäniemi, Jenni E

    2016-01-01

    Pygospio elegans is an opportunistic, wide-spread spionid polychaete that reproduces asexually via fragmentation and can produce benthic and pelagic larvae, hence combining different developmental modes in one species. We documented the density, size distribution, and reproductive activity of P....... elegans at four sites in the Danish Isefjord-Roskilde Fjord estuary complex, where all modes of reproduction were reported. We compared population dynamics of this species to environmental parameters such as salinity, temperature, and sediment characteristics (grain size, sorting, porosity, water content......, organic content, C/N). We observed that new cohorts—resulting either from sexual or asexual reproduction—appeared in spring and fall, and old ones disappeared in late summer and winter. Sexual reproduction occurred from September until May, and although their timing was variable, there were two...

  3. Membrane biofouling in a wastewater nitrification reactor: Microbial succession from autotrophic colonization to heterotrophic domination.

    Science.gov (United States)

    Lu, Huijie; Xue, Zheng; Saikaly, Pascal; Nunes, Suzana P; Bluver, Ted R; Liu, Wen-Tso

    2016-01-01

    Membrane biofouling is a complex process that involves bacterial adhesion, extracellular polymeric substances (EPS) excretion and utilization, and species interactions. To obtain a better understanding of the microbial ecology of biofouling process, this study conducted rigorous, time-course analyses on the structure, EPS and microbial composition of the fouling layer developed on ultrafiltration membranes in a nitrification bioreactor. During a 14-day fouling event, three phases were determined according to the flux decline and microbial succession patterns. In Phase I (0-2 days), small sludge flocs in the bulk liquid were selectively attached on membrane surfaces, leading to the formation of similar EPS and microbial community composition as the early biofilms. Dominant populations in small flocs, e.g., Nitrosomonas, Nitrobacter, and Acinetobacter spp., were also the major initial colonizers on membranes. In Phase II (2-4 d), fouling layer structure, EPS composition, and bacterial community went through significant changes. Initial colonizers were replaced by fast-growing and metabolically versatile heterotrophs (e.g., unclassified Sphingobacteria). The declining EPS polysaccharide to protein (PS:PN) ratios could be correlated well with the increase in microbial community diversity. In Phase III (5-14 d), heterotrophs comprised over 90% of the community, whereas biofilm structure and EPS composition remained relatively stable. In all phases, AOB and NOB were constantly found within the top 40% of the fouling layer, with the maximum concentrations around 15% from the top. The overall microbial succession pattern from autotrophic colonization to heterotrophic domination implied that MBR biofouling could be alleviated by forming larger bacterial flocs in bioreactor suspension (reducing autotrophic colonization), and by designing more specific cleaning procedures targeting dominant heterotrophs during typical filtration cycles. Copyright © 2015 Elsevier Ltd. All

  4. Microwhip scorpions (Palpigradi) feed on heterotrophic cyanobacteria in Slovak caves - a curiosity among Arachnida

    Czech Academy of Sciences Publication Activity Database

    Smrž, J.; Kováč, L.; Mikeš, J.; Lukešová, Alena

    2013-01-01

    Roč. 8, č. 10 (2013), e75989 E-ISSN 1932-6203 Institutional support: RVO:60077344 Keywords : microwhip scorpions * heterotrophic cyanobacteria * Slovak caves Subject RIV: EG - Zoology Impact factor: 3.534, year: 2013

  5. Heterotrophic denitrification vs. autotrophic anammox – quantifying collateral effects on the oceanic carbon cycle

    Directory of Open Access Journals (Sweden)

    W. Koeve

    2010-08-01

    Full Text Available The conversion of fixed nitrogen to N2 in suboxic waters is estimated to contribute roughly a third to total oceanic losses of fixed nitrogen and is hence understood to be of major importance to global oceanic production and, therefore, to the role of the ocean as a sink of atmospheric CO2. At present heterotrophic denitrification and autotrophic anammox are considered the dominant sinks of fixed nitrogen. Recently, it has been suggested that the trophic nature of pelagic N2-production may have additional, "collateral" effects on the carbon cycle, where heterotrophic denitrification provides a shallow source of CO2 and autotrophic anammox a shallow sink. Here, we analyse the stoichiometries of nitrogen and associated carbon conversions in marine oxygen minimum zones (OMZ focusing on heterotrophic denitrification, autotrophic anammox, and dissimilatory nitrate reduction to nitrite and ammonium in order to test this hypothesis quantitatively. For open ocean OMZs the combined effects of these processes turn out to be clearly heterotrophic, even with high shares of the autotrophic anammox reaction in total N2-production and including various combinations of dissimilatory processes which provide the substrates to anammox. In such systems, the degree of heterotrophy (ΔCO2:ΔN2, varying between 1.7 and 6.5, is a function of the efficiency of nitrogen conversion. On the contrary, in systems like the Black Sea, where suboxic N-conversions are supported by diffusive fluxes of NH4+ originating from neighbouring waters with sulphate reduction, much lower values of ΔCO2:ΔN2 can be found. However, accounting for concomitant diffusive fluxes of CO2, the ratio approaches higher values similar to those computed for open ocean OMZs. Based on this analysis, we question the significance of collateral effects concerning the trophic

  6. Burial of Zostera marina seeds in sediment inhabited by three polychaetes: laboratory and field studies

    DEFF Research Database (Denmark)

    Delefosse, Matthieu; Kristensen, Erik

    2012-01-01

    The large number of seeds produced by eelgrass, Zostera marina, provides this plant with a potential to disperse widely and colonise newareas. After dispersal, seedsmust be buried into sediment for assuring long-term survival, successful germination and safe seedling development. Seedsmay be buried...... eelgrass seed bank at the ecosystemscale. Some species have a positive effect by burying seeds to shallow depths and thereby reducing seed predation and facilitating seed germination, while other species bury seeds too deep for successful seed germination and seedling development....... passively by sedimentation or actively through sediment reworking by benthic fauna.We evaluated the effect of three polychaetes on the burial rate and depth of eelgrass seeds. Burial was first measured in controlled laboratory experiments using different densities of Nereis (Hediste) diversicolor (400...

  7. A "footprint" of plant carbon fixation cycle functions during the development of a heterotrophic fungus.

    Science.gov (United States)

    Lyu, Xueliang; Shen, Cuicui; Xie, Jiatao; Fu, Yanping; Jiang, Daohong; Hu, Zijin; Tang, Lihua; Tang, Liguang; Ding, Feng; Li, Kunfei; Wu, Song; Hu, Yanping; Luo, Lilian; Li, Yuanhao; Wang, Qihua; Li, Guoqing; Cheng, Jiasen

    2015-08-11

    Carbon fixation pathway of plants (CFPP) in photosynthesis converts solar energy to biomass, bio-products and biofuel. Intriguingly, a large number of heterotrophic fungi also possess enzymes functionally associated with CFPP, raising the questions about their roles in fungal development and in evolution. Here, we report on the presence of 17 CFPP associated enzymes (ten in Calvin-Benson-Basham reductive pentose phosphate pathway and seven in C4-dicarboxylic acid cycle) in the genome of Sclerotinia sclerotiorum, a heterotrophic phytopathogenic fungus, and only two unique enzymes: ribulose-1, 5-bisphosphate carboxylase-oxygenase (Rubisco) and phosphoribulokinase (PRK) were absent. This data suggested an incomplete CFPP-like pathway (CLP) in fungi. Functional profile analysis demonstrated that the activity of the incomplete CLP was dramatically regulated during different developmental stages of S. sclerotiorum. Subsequent experiments confirmed that many of them were essential to the virulence and/or sclerotial formation. Most of the CLP associated genes are conserved in fungi. Phylogenetic analysis showed that many of them have undergone gene duplication, gene acquisition or loss and functional diversification in evolutionary history. These findings showed an evolutionary links in the carbon fixation processes of autotrophs and heterotrophs and implicated the functions of related genes were in course of continuous change in different organisms in evolution.

  8. Feeding, growth and metabolism of the marine heterotrophic dinoflagellate Gyrodinium dominans

    DEFF Research Database (Denmark)

    Schmoker, Claire; Thor, Peter; Hernández-león, Santiago

    2011-01-01

    may inflict high metabolic costs. Gross growth efficiencies (GGEs), determined for G. dominans in both food availability conditions, were within the range of values reported for other heterotrophic protozoans, and while GGE decreased when concentrations of food were high in organisms fed a single...... pulse of food, the opposite was observed in organisms acclimatized to a constant level of food....

  9. Biogeochemical analysis of the calcification patterns of cold-water corals Madrepora oculata and Lophelia pertusa along contact surfaces with calcified tubes of the symbiotic polychaete Eunice norvegica: Evaluation of a 'mucus' calcification hypothesis

    Science.gov (United States)

    Oppelt, Alexandra; López Correa, Matthias; Rocha, Carlos

    2017-09-01

    The scleractinian cold-water corals (CWCs), including the species Madrepora oculata and especially Lophelia pertusa, have been studied extensively in an attempt to decipher environmental signals recorded during biomineralisation in order to extract environmental chronologies. However, understanding the mechanisms of carbonate precipitation is a prerequisite to interpret variations in geochemical signatures locked into the skeleton during coral growth; to date results are still inconclusive. Here a novel approach, comparing the calcification patterns within the coral microstructure of species L. pertusa and M. oculata and the geochemistry along the contact surfaces with calcified polychaete tubes is undertaken to provide additional information on the mechanisms of biomineralisation in colonial corals. The fact that no significant difference in microstructures, variations in growth rate, or geochemical composition between the corallite theca and the calcified polychaete tube was detectable leads to the conclusion that both have been deposited by the coral tissue in L. pertusa and M. oculata. Based on prior knowledge on the symbiotic relationship between CWCs and the polychaete Eunice norvegica, an involvement of mucus in the calcification of the parchment tubes had been suspected. However, we found only evidence for aragonite precipitated by coral tissue, without evidence for an involvement of mucus in the calcification.

  10. Heterotrophic cultivation of Chlorella pyrenoidosa using sucrose as the sole carbon source by co-culture with Rhodotorula glutinis.

    Science.gov (United States)

    Wang, Shikai; Wu, Yong; Wang, Xu

    2016-11-01

    Heterotrophic cultivation of microalgae is a feasible alternative strategy to avoid the light limitation of photoautotrophic culture, but the heterotrophic utilization of disaccharides is difficult for microalgae. Aimed at this problem, a co-culture system was developed by mix culture of C. pyrenoidosa and R. glutinis using sucrose as the sole carbon source. In this system, C. pyrenoidosa could utilize glucose and fructose which were hydrolyzed from sucrose by R. glutinis. The highest specific growth rate and final cell number proportion of algae was 1.02day(-1) and 45%, respectively, when cultured at the initial algal cell number proportion of 95.24% and the final algal cell density was 111.48×10(6)cells/mL. In addition, the lipid content was also promoted due to the synergistic effects in mix culture. This study provides a novel approach using sucrose-riched wastes for the heterotrophic culture of microalgae and may effectively decrease the cost of carbon source. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Dynamics of pollution-indicator and heterotrophic bacteria in sewage treatment lagoons.

    Science.gov (United States)

    Legendre, P; Baleux, B; Troussellier, M

    1984-09-01

    The spatio-temporal dynamics of pollution-indicator bacteria and aerobic heterotrophic bacteria were studied in the sewage treatment lagoons of an urban wastewater center after 26 months of biweekly sampling at eight stations in these lagoons. Robust statistical methods of time-series analysis were used to study successional steps (through chronological clustering) and rhythmic behavior through time (through contingency periodogram). The aerobic heterotrophic bacterial community showed two types of temporal evolution: in the first four stations, it seems mainly controlled by the nutrient support capacity of the sewage input, whereas in the remaining part of the lagoon, it seems likely that the pollution-indicator bacteria are gradually replaced by other bacterial types that are better adapted to this environment. On the other hand, the pollution-indicator bacteria showed an annual cycle which increased in amplitude at distances further from the wastewater source. The main events in this cycle were produced simultaneously at all stations, indicating control of these bacterial populations by climatic factors, which act through physical and chemical factors, and also through other biological components of this ecosystem (phytoplankton and zooplankton). Finally, we use results from this study to suggest a modified design for a future study program.

  12. Best practices in heterotrophic high-cell-density microalgal processes: achievements, potential and possible limitations

    Czech Academy of Sciences Publication Activity Database

    Bumbak, F.; Cook, S.; Zachleder, Vilém; Hauser, S.; Kovar, K.

    2011-01-01

    Roč. 91, č. 1 (2011), 31-46 ISSN 0175-7598 Institutional research plan: CEZ:AV0Z50200510 Keywords : Heterotrophic growth * Microalgae * High-celldensity culture Subject RIV: EE - Microbiology, Virology Impact factor: 3.425, year: 2011

  13. Heterotrophic compensation: a possible mechanism for resilience of coral reefs to global warming or a sign of prolonged stress?

    Directory of Open Access Journals (Sweden)

    Adam D Hughes

    Full Text Available Thermally induced bleaching has caused a global decline in corals and the frequency of such bleaching events will increase. Thermal bleaching severely disrupts the trophic behaviour of the coral holobiont, reducing the photosynthetically derived energy available to the coral host. In the short term this reduction in energy transfer from endosymbiotic algae results in an energy deficit for the coral host. If the bleaching event is short-lived then the coral may survive this energy deficit by depleting its lipid reserves, or by increasing heterotrophic energy acquisition. We show for the first time that the coral animal is capable of increasing the amount of heterotrophic carbon incorporated into its tissues for almost a year following bleaching. This prolonged heterotrophic compensation could be a sign of resilience or prolonged stress. If the heterotrophic compensation is in fact an acclimatization response, then this physiological response could act as a buffer from future bleaching by providing sufficient heterotrophic energy to compensate for photoautotrophic energy losses during bleaching, and potentially minimizing the effect of subsequent elevated temperature stresses. However, if the elevated incorporation of zooplankton is a sign that the effects of bleaching continue to be stressful on the holobiont, even after 11 months of recovery, then this physiological response would indicate that complete coral recovery requires more than 11 months to achieve. If coral bleaching becomes an annual global phenomenon by mid-century, then present temporal refugia will not be sufficient to allow coral colonies to recover between bleaching events and coral reefs will become increasingly less resilient to future climate change. If, however, increasing their sequestration of zooplankton-derived nutrition into their tissues over prolonged periods of time is a compensating mechanism, the impacts of annual bleaching may be reduced. Thus, some coral species

  14. Membrane biofouling in a wastewater nitrification reactor: microbial succession from autotrophic colonization to heterotrophic domination

    KAUST Repository

    Lu, Huijie; Xue, Zheng; Saikaly, Pascal; Nunes, Suzana Pereira; Bluver, Ted R.; Liu, Wen-Tso

    2015-01-01

    through significant changes. Initial colonizers were replaced by fast-growing and metabolically versatile heterotrophs (e.g., unclassified Sphingobacteria). The declining EPS polysaccharide to protein (PS:PN) ratios could be correlated well

  15. Cultivation-Independent and Cultivation-Dependent Analysis of Microbes in the Shallow-Sea Hydrothermal System Off Kueishantao Island, Taiwan: Unmasking Heterotrophic Bacterial Diversity and Functional Capacity.

    Science.gov (United States)

    Tang, Kai; Zhang, Yao; Lin, Dan; Han, Yu; Chen, Chen-Tung A; Wang, Deli; Lin, Yu-Shih; Sun, Jia; Zheng, Qiang; Jiao, Nianzhi

    2018-01-01

    Shallow-sea hydrothermal systems experience continuous fluctuations of physicochemical conditions due to seawater influx which generates variable habitats, affecting the phylogenetic composition and metabolic potential of microbial communities. Until recently, studies of submarine hydrothermal communities have focused primarily on chemolithoautotrophic organisms, however, there have been limited studies on heterotrophic bacteria. Here, fluorescence in situ hybridization, high throughput 16S rRNA gene amplicon sequencing, and functional metagenomes were used to assess microbial communities from the shallow-sea hydrothermal system off Kueishantao Island, Taiwan. The results showed that the shallow-sea hydrothermal system harbored not only autotrophic bacteria but abundant heterotrophic bacteria. The potential for marker genes sulfur oxidation and carbon fixation were detected in the metagenome datasets, suggesting a role for sulfur and carbon cycling in the shallow-sea hydrothermal system. Furthermore, the presence of diverse genes that encode transporters, glycoside hydrolases, and peptidase indicates the genetic potential for heterotrophic utilization of organic substrates. A total of 408 cultivable heterotrophic bacteria were isolated, in which the taxonomic families typically associated with oligotrophy, copiotrophy, and phototrophy were frequently found. The cultivation-independent and -dependent analyses performed herein show that Alphaproteobacteria and Gammaproteobacteria represent the dominant heterotrophs in the investigated shallow-sea hydrothermal system. Genomic and physiological characterization of a novel strain P5 obtained in this study, belonging to the genus Rhodovulum within Alphaproteobacteria, provides an example of heterotrophic bacteria with major functional capacity presented in the metagenome datasets. Collectively, in addition to autotrophic bacteria, the shallow-sea hydrothermal system also harbors many heterotrophic bacteria with versatile

  16. Biochemical System Analysis of Lutein Production by Heterotrophic Chlorella pyrenoidosa in a Fermentor

    Directory of Open Access Journals (Sweden)

    Zheng-Yun Wu

    2009-01-01

    Full Text Available Chlorella is a promising alternative source of lutein, as it can be cultivated heterotrophically with high efficiency. In this study, the carotenoids in Chlorella pyrenoidosa heterotrophically cultivated in a 19-litre fermentor have been analyzed and determined by using HPLC and HPLC-MS. A biochemical system theory (BST model was developed for understanding the regulatory features of carotenoid metabolism during the batch cultivation. Factors that influence lutein production by C. pyrenoidosa were discussed based on the model. It shows that low flux for lycopene formation is the major bottleneck for lutein production, while by-product syntheses and inhibitions affect the cellular lutein content much less. However, with further increase of the cellular lutein content, the inhibition on lycopene formation by lutein may become a limiting factor. Although speculative, these results may provide useful information for further elucidation of the regulatory mechanisms of carotenoid biosynthesis in Chlorella and modifying its metabolic network to enhance lutein production.

  17. Comparison of heterotrophic and autotrophic denitrification processes for nitrate removal from phosphorus-limited surface water.

    Science.gov (United States)

    Wang, Zheng; He, Shengbing; Huang, Jungchen; Zhou, Weili; Chen, Wanning

    2018-03-29

    Phosphorus (P) limitation has been demonstrated for micro-polluted surface water denitrification treatment in previous study. In this paper, a lab-scale comparative study of autotrophic denitrification (ADN) and heterotrophic denitrification (HDN) in phosphorus-limited surface water was investigated, aiming to find out the optimal nitrogen/phosphorus (N/P) ratio and the mechanism of the effect of P limitation on ADN and HDN. Furthermore, the optimal denitrification process was applied to the West Lake denitrification project, aiming to improve the water quality of the West Lake from worse than grade V to grade IV (GB3838-2006). The lab-scale study showed that the lack of P indeed inhibited HDN more greatly than ADN. The optimal N/P ratio for ADN and HDN was 25 and a 0.15 mg PO 4 3- -P L -1 of microbial available phosphorus (MAP) was observed. P additions could greatly enhance the resistance of ADN and HDN to hydraulic loading shock. Besides, The P addition could effectively stimulate the HDN performance via enriching the heterotrophic denitrifiers and the denitrifying phosphate-accumulating organisms (DNPAOs). Additionally, HDN was more effective and cost-effective than ADN for treating P-limited surface water. The study of the full-scale HDBF (heterotrophic denitrification biofilter) indicated that the denitrification performance was periodically impacted by P limitation, particularly at low water temperatures. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Nitrogen uptake by heterotrophic bacteria and phytoplankton in the nitrate-rich Thames estuary

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.

    2000-01-01

    The uptake of ammonium, nitrate, amino acids and urea was examined in the nitrate-rich Thames estuary and adjacent area in the North Sea during February 1999. The majority of uptake was by heterotrophic bacteria, as demonstrated by addition of a prokaryotic inhibitor that lowered uptake rates by 82,

  19. Decadal warming causes a consistent and persistent shift from heterotrophic to autotrophic respiration in contrasting permafrost ecosystems.

    Science.gov (United States)

    Hicks Pries, Caitlin E; van Logtestijn, Richard S P; Schuur, Edward A G; Natali, Susan M; Cornelissen, Johannes H C; Aerts, Rien; Dorrepaal, Ellen

    2015-12-01

    Soil carbon in permafrost ecosystems has the potential to become a major positive feedback to climate change if permafrost thaw increases heterotrophic decomposition. However, warming can also stimulate autotrophic production leading to increased ecosystem carbon storage-a negative climate change feedback. Few studies partitioning ecosystem respiration examine decadal warming effects or compare responses among ecosystems. Here, we first examined how 11 years of warming during different seasons affected autotrophic and heterotrophic respiration in a bryophyte-dominated peatland in Abisko, Sweden. We used natural abundance radiocarbon to partition ecosystem respiration into autotrophic respiration, associated with production, and heterotrophic decomposition. Summertime warming decreased the age of carbon respired by the ecosystem due to increased proportional contributions from autotrophic and young soil respiration and decreased proportional contributions from old soil. Summertime warming's large effect was due to not only warmer air temperatures during the growing season, but also to warmer deep soils year-round. Second, we compared ecosystem respiration responses between two contrasting ecosystems, the Abisko peatland and a tussock-dominated tundra in Healy, Alaska. Each ecosystem had two different timescales of warming (permafrost ecosystems. © 2015 John Wiley & Sons Ltd.

  20. Draft Genome Sequence of an Active Heterotrophic Nitrifier-Denitrifier, Cupriavidus pauculus UM1

    OpenAIRE

    Putonti, Catherine; Polley, Nathaniel; Castignetti, Domenic

    2018-01-01

    ABSTRACT Here, we present the draft genome sequence of Cupriavidus pauculus UM1, a metal-resistant heterotrophic nitrifier-denitrifier capable of synthesizing nitrite from pyruvic oxime. The size of the genome is 7,402,815 bp with a GC content of 64.8%. This draft assembly consists of 38 scaffolds.

  1. Synechococcus growth in the ocean may depend on the lysis of heterotrophic bacteria

    Czech Academy of Sciences Publication Activity Database

    Weinbauer, M.G.; Bonilla-Findji, O.; Chan, A.M.; Dolan, J. R.; Short, S.M.; Šimek, Karel; Wilhelm, S. W.; Suttle, C.A.

    2011-01-01

    Roč. 33, č. 10 (2011), s. 1465-1476 ISSN 0142-7873 R&D Projects: GA ČR(CZ) GA206/08/0015 Institutional research plan: CEZ:AV0Z60170517 Keywords : viruses * growth control of cyanobacteria * heterotrophic bacterioplankton Subject RIV: EE - Microbiology, Virology Impact factor: 2.079, year: 2011

  2. Regulation of annual variation in heterotrophic bacterial production in the Schelde estuary (SW Netherlands)

    NARCIS (Netherlands)

    Goosen, N.K.; Van Rijswijk, P.; Kromkamp, J.C.; Peene, J.

    1997-01-01

    Heterotrophic bacterioplankton production (H-3-thymidine incorporation rate) and abundance in the surface water of the Schelde estuary (The Netherlands) were studied during an annual cycle in 1991 along the salinity gradient (0.8 to 33 psu). Bacterial production and numbers increased from the lower

  3. Compared microbiology of granular sludge under autotrophic, mixotrophic and heterotrophic denitrification conditions.

    Science.gov (United States)

    Fernández, N; Sierra-Alvarez, R; Amils, R; Field, J A; Sanz, J L

    2009-01-01

    Water contamination by nitrate is a wideworld extended phenomena. Biological autotrophic denitrification has a real potential to face this problem and presents less drawbacks than the most extended heterotrophic denitrification. Three bench-scale UASB reactors were operated under autotrophic (R1, H2S as electron donor), mixotrophic (R2, H2S plus p-cresol as electron donors) and heterotrophic (R3, p-cresol as electron donor) conditions using nitrate as terminal electron acceptor. 16S rDNA genetic libraries were built up to compare their microbial biodiversity. Six different bacteria phyla and three archaeal classes were observed. Proteobacteria was the main phyla in all reactors standing out the presence of denitrifiers. Microorganisms similar to Thiobacillus denitrificans and Acidovorax sp. performed the autotrophic denitification. These OTUs were displaced by chemoheterotrophic denitrifiers, especially by Limnobacter-like and Ottowia-like OTUs. Other phyla were Bacteroidetes, Chloroflexi, Firmicutes and Actinobacteria that--as well as Archaea members--were implicated in the degradation of organic matter, as substrate added as coming from endogenous sludge decay under autotrophic conditions. Archaea diversity remained low in all the reactors being Methanosaeta concilii the most abundant one.

  4. Toxic effects and bioaccumulation of nano-, micron-, and ionic-Ag on the polychaete, Nereis diversicolor

    DEFF Research Database (Denmark)

    Cong, Yi; Banta, Gary Thomas; Selck, Henriette

    2011-01-01

    There is increasing concern about the toxicities and potential risks, both still poorly understood, of silver nanoparticles for the aquatic environment after their eventual release via wastewater discharges. In this study, the toxicities of sediment associated nano (...)- and ionic (AgNO3)- Ag on the sediment-dwelling polychaete, Nereis diversicolor, were compared after 10 days of sediment exposure, using survival, DNA damage (comet assay) and bioaccumulation as endpoints. The nominal concentrations used in all exposure scenarios were 0, 1, 5, 10, 25, and 50 g Ag/g dry...... weight (dw) sediment. Our results showed that Ag was able to cause DNA damage in Nereis coelomocytes, and that this effect was both concentration- and Ag form-related. There was significantly greater genotoxicity (higher tail moment and tail DNA intensities) at 25 and 50 g/g dw in nano- and micron-Ag...

  5. Expression pattern of arenicins - the antimicrobial peptides of polychaete Arenicolamarina

    Directory of Open Access Journals (Sweden)

    Arina L. Maltseva

    2014-12-01

    Full Text Available Immune responses of invertebrate animals are mediated through innate mechanisms, among which production of antimicrobial peptides play an important role. Although evolutionary Polychaetes represent an interesting group closely related to a putative common ancestor of other coelomates, their immune mechanisms still remain scarcely investigated. Previously our group has identified arenicins - new antimicrobial peptides of the lugworm Arenicola marina, since then these peptides were thoroughly characterized in terms of their structure and inhibitory potential. In the present study we addressed the question of the physiological functions of arenicins in the lugworm body. Using molecular and immunocytochemical methods we demonstrated that arencins are expressed in the wide range of the lugworm tissues - coelomocytes, body wall, extravasal tissue and the gut. The expression of arenicins is constitutive and does not depend on stimulation of various infectious stimuli. Most intensively arenicins are produced by mature coelomocytes where they function as killing agents inside the phagolysosome. In the gut and the body wall epithelia arenicins are released from producing cells via secretion as they are found both inside the epithelial cells and in the contents of the cuticle. Collectively our study showed that arenicins are found in different body compartments responsible for providing a first line of defence against infections, which implies their important role as key components of both epithelial and systemic branches of host defence.

  6. Aspects on gametogenesis, fertilization and embryogenesis of two deep-sea polychaetes from Eastern Atlantic cold seeps

    Science.gov (United States)

    Gaudron, S. M.; Hourdez, S.; Olu, K.

    2017-11-01

    We investigated two gonochoristic species of annelid polychaetes (one siboglinid and one polynoid) from cold seeps that ranged from 525 m to 3300 m in depth (Guiness, Worm Hole and Regab pockmarks) on the Gabon and Congo continental margins (Gulf of Guinea). Different aspects of gametogenesis (oocyte diameter, presence of ovisac, spermatozoa shape, and fecundity), fertilization (in vitro fertilization experiments: IVF) and embryogenesis (cleavage rate) were studied. The sampled siboglinid was a new species of Lamellibrachia and the second population of this genus in the Eastern Atlantic. Mean oocyte diameter was about 100 μm and fully-grown primary oocytes were stored in an ovisac, as in other studied siboglinids. The presence of a single spermatozoon was noted within an oviduct, indicating a possible internal fertilization. The rate of cell division at 6 °C was one cleavage every 20 h. Embryos developed normally to the blastula stage after 5-d post-fertilization at atmospheric pressure suggesting some pressure tolerance. The second polychaete was the scale-worm Branchipolynoe cf. seepensis that lives in commensalism in the mantle cavity of Bathymodiolus aff. boomerang. Anatomical reproductive features were similar to those described in B. seepensis from hydrothermal vents on Mid-Atlantic Ridge, with lecithotrophic larval development and continuous gametogenesis. We performed the first IVF carried out on gametes for any deep-sea polynoid species. Fertilization and development occurred but a number of abnormalities were observed demonstrating a limitation to embryogenesis at atmospheric pressure. The rate of cell division was three times faster at 8 °C than at 4 °C with a maximum stage of 8-cells reached after 72 h post-fertilization. We surprisingly observed some oocytes from the negative seawater control during IVF experiments cleaved to the 2-cell stage, demonstrating the possible occurrence of internal fertilization prior to IVF experiment or the accidental

  7. Influence of river discharge on abundance and dissemination of heterotrophic, indicator and pathogenic bacteria along the East Coast of India.

    Science.gov (United States)

    Prasad, V R; Srinivas, T N R; Sarma, V V S S

    2015-06-15

    In order to examine the influence of discharge from different rivers from peninsular India and urban sewage on intensity and dissemination of heterotrophic, indicator and pathogenic bacteria, a study was carried out during peak discharge period along coastal Bay of Bengal. The coastal Bay received freshwater inputs from the river Ganges while Godavari and Krishna contributed to the south. Contrasting difference in salinity, temperature, nutrients and organic matter was observed between north and south east coast of India. The highest heterotrophic, indicator and pathogenic bacterial abundance was observed in the central coastal Bay that received urban sewage from the major city. Intensity and dissemination of heterotrophic, indicator and pathogenic bacteria displayed linear relation with magnitude of discharge. The coliform load was observed up to 100km from the coast suggesting that marine waters were polluted during the monsoon season and its impact on the ecosystem needs further studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Effects of substrate concentrations on the growth of heterotrophic bacteria and algae in secondary facultative ponds.

    Science.gov (United States)

    Kayombo, S; Mbwette, T S A; Katima, J H Y; Jorgensen, S E

    2003-07-01

    This paper presents the effect of substrate concentration on the growth of a mixed culture of algae and heterotrophic bacteria in secondary facultative ponds (SFPs) utilizing settled domestic sewage as a sole source of organic carbon. The growth of the mixed culture was studied at the concentrations ranging between 200 and 800 mg COD/l in a series of batch chemostat reactors. From the laboratory data, the specific growth rate (micro) was determined using the modified Gompertz model. The maximum specific growth rate ( micro(max)) and half saturation coefficients (K(s)) were calculated using the Monod kinetic equation. The maximum observed growth rate ( micro(max)) for heterotrophic bacteria was 3.8 day(-1) with K(s) of 200 mg COD/l. The micro(max) for algal biomass based on suspended volatile solids was 2.7 day(-1) with K(s) of 110 mg COD/l. The micro(max) of algae based on the chlorophyll-a was 3.5 day(-1) at K(s) of 50mg COD/l. The observed specific substrate removal by heterotrophic bacteria varied between the concentrations of substrate used and the average value was 0.82 (mg COD/mg biomass). The specific substrate utilization rate in the bioreactors was direct proportional to the specific growth rate. Hence, the determined Monod kinetic parameters are useful for the definition of the operation of SFPs.

  9. Factor driving heterotrophic dinoflagellate in relation to environment conditions in Kerkennah Islands (eastern coast of Tunisa

    Directory of Open Access Journals (Sweden)

    Mounir Ben Brahim

    2015-09-01

    Full Text Available Objective: To study the seasonal variability of heterotrophic dinoflagellate in the station of Cercina (southern coast of Tunisia. Methods: Sampling was done in 2007 in Cercina station located in the western coast of Kerkennah (34°41'27'' N; 11°07'45'' E (Southern Tunisia. Three replicates of water samples were taken during 10 days of each month. Environmental variables and nutrients were measured in situ. Results: A significant seasonal difference was observed for temperature and water salinity. The highest values were observed in spring and summer. No significant seasonal difference was, however, detected for nitrite, nitrate, ammonia, silica and phosphate. Sixty-five species of dinoflagellate were identified in the station of Cercina. Abundance of dinoflagellates fluctuated between seasons with values showing a significant seasonal and monthly difference. The highest mean abundance was recorded in spring in April, while the lowest abundance was detected in December in winter. Protoperidinium granii was the main species contributing to the dissimilarity between spring and winter with 13.98% followed by Peridinium sp. with 12.5% of dissimilarity and by Polykrikos sp. with 10.58%. Conclusions: Heterotrophic dinoflagellates proliferate in spring and summer. This increase was justified by the nutrient availability. Protoperidinium granii and Polykrikos kofoidii were the main heterotrophic dinoflagellate making difference between seasons and their densities were positively correlated with both temperature and salinity.

  10. Temperature regulation of marine heterotrophic prokaryotes increases latitudinally as a breach between bottom-up and top-down controls

    KAUST Repository

    Moran, Xose Anxelu G.

    2017-04-19

    Planktonic heterotrophic prokaryotes make up the largest living biomass and process most organic matter in the ocean. Determining when and where the biomass and activity of heterotrophic prokaryotes are controlled by resource availability (bottom-up), predation and viral lysis (top-down) or temperature will help in future carbon cycling predictions. We conducted an extensive survey across subtropical and tropical waters of the Atlantic, Indian and Pacific Oceans during the Malaspina 2010 Global Circumnavigation Expedition and assessed indices for these three types of controls at 109 stations (mostly from the surface to 4000 m depth). Temperature control was approached by the apparent activation energy in eV (ranging from 0.46 to 3.41), bottom-up control by the slope of the log-log relationship between biomass and production rate (ranging from -0.12 to 1.09) and top-down control by an index that considers the relative abundances of heterotrophic nanoflagellates and viruses (ranging from 0.82 to 4.83). We conclude that temperature becomes dominant (i.e. activation energy >1.5 eV) within a narrow window of intermediate values of bottom-up (0.3-0.6) and top-down 0.8-1.2) controls. A pervasive latitudinal pattern of decreasing temperature regulation towards the Equator, regardless of the oceanic basin, suggests that the impact of global warming on marine microbes and their biogeochemical function will be more intense at higher latitudes. Our analysis predicts that 1°C ocean warming will result in increased biomass of heterotrophic prokaryoplankton only in waters with <26°C of mean annual surface temperature. This article is protected by copyright. All rights reserved.

  11. Draft Genome Sequence of an Active Heterotrophic Nitrifier-Denitrifier, Cupriavidus pauculus UM1.

    Science.gov (United States)

    Putonti, Catherine; Polley, Nathaniel; Castignetti, Domenic

    2018-02-08

    Here, we present the draft genome sequence of Cupriavidus pauculus UM1, a metal-resistant heterotrophic nitrifier-denitrifier capable of synthesizing nitrite from pyruvic oxime. The size of the genome is 7,402,815 bp with a GC content of 64.8%. This draft assembly consists of 38 scaffolds. Copyright © 2018 Putonti et al.

  12. Copper affects biofilm inductiveness to larval settlement of the serpulid polychaete Hydroides elegans (Haswell)

    KAUST Repository

    Bao, Wei Yang; Lee, On On; Chung, Hong Chun; Li, Mu; Qian, Pei Yuan

    2010-01-01

    Copper (Cu) contamination is a potential threat to the marine environment due to the use of Cu-based antifouling paints. Cu stress on larval settlement of the polychaete Hydroides elegans was investigated, and this was linked to Cu stress on biofilms and on the biofilm development process. The inductiveness of young biofilms was more easily altered by Cu stress than that of old biofilms, indicating the relative vulnerability of young biofilms. This might result from changes in bacterial survival, the bacterial community composition and the chemical profiles of young biofilms. Cu also affected biofilm development and the chemical high performance liquid chromatograph fingerprint profile. The results indicate that Cu affected larval settlement mainly through its effect on the process of biofilm development in the marine environment, and the chemical profile was crucial to biofilm inductiveness. It is strongly recommended that the effects of environmentally toxic substances on biofilms are evaluated in ecotoxicity bioassays using larval settlement of invertebrates as the end point. © 2010 Taylor & Francis.

  13. Drilling Predation on Serpulid Polychaetes (Ditrupa arietina) from the Pliocene of the Cope Basin, Murcia Region, Southeastern Spain

    Science.gov (United States)

    Martinell, Jordi; Kowalewski, Michał; Domènech, Rosa

    2012-01-01

    We report quantitative analyses of drilling predation on the free-living, tube-dwelling serpulid polychaete Ditrupa arietina from the Cope Cabo marine succession (Pliocene, Spain). Tubes of D. arietina are abundant in the sampled units: 9 bulk samples from 5 horizons yielded ∼5925 specimens of D. arietina. Except for fragmentation, tubes were well preserved. Complete specimens ranged from 3.1 to 13.4 mm in length and displayed allometric growth patterns, with larger specimens being relatively slimmer. Drilled Ditrupa tubes were observed in all samples. Drillholes, identified as Oichnus paraboloides, were characterized by circular to elliptical outline (drillhole eccentricity increased with its diameter), parabolic vertical profile, outer diameter larger than inner diameter, penetration of one tube wall only, narrow range of drill-hole sizes, and non-random (anterior) distribution of drillholes. A total of 233 drilled specimens were identified, with drilling frequencies varying across horizons from 2.7% to 21% (3.9% for pooled data). Many tube fragments were broken across a drillhole suggesting that the reported frequencies are conservative and that biologically-facilitated (drill-hole induced) fragmentation hampers fossil preservation of complete serpulid tubes. No failed or repaired holes were observed. Multiple complete drillholes were present (3.9%). Drilled specimens were significantly smaller than undrilled specimens and tube length and drill-hole diameter were weakly correlated. The results suggest that drillholes were produced by a size-selective, site-stereotypic predatory organism of unknown affinity. The qualitative and quantitative patterns reported here are mostly consistent with previous reports on recent and fossil Ditrupa and reveal parallels with drilling patterns documented for scaphopod mollusks, a group that is ecologically and morphologically similar to Ditrupa. Consistent with previous studies, the results suggest that free-dwelling serpulid

  14. A method for measuring losses of soil carbon by heterotrophic respiration from peat soils under oil palms

    Science.gov (United States)

    Farmer, Jenny; Manning, Frances; Smith, Jo; Arn Teh, Yit

    2017-04-01

    The effects of drainage and deforestation of South East Asian peat swamp forests for the development of oil palm plantations has received considerable attention in both mainstream media and academia, and is the source of significant discussion and debate. However, data on the long-term carbon losses from these peat soils as a result of this land use change is still limited and the methods with which to collect this data are still developing. Here we present the ongoing evolution and implementation of a method for separating autotrophic and heterotrophic respiration by sampling carbon dioxide emissions at increasing distance from palm trees. We present the limitations of the method, modelling approaches and results from our studies. In 2011 we trialled this method in Sumatra, Indonesia and collected rate measurements over a six day period in three ages of oil palm. In the four year oil palm site there were thirteen collars that had no roots present and from these the peat based carbon losses were recorded to be 0.44 g CO2 m2 hr-1 [0.34; 0.57] (equivalent to 39 t CO2 ha-1 yr-1 [30; 50]) with a mean water table depth of 0.40 m, or 63% of the measured total respiration across the plot. In the two older palm sites of six and seven years, only one collar out of 100 had no roots present, and thus a linear random effects model was developed to calculate heterotrophic emissions for different distances from the palm tree. This model suggested that heterotrophic respiration was between 37 - 59% of total respiration in the six year old plantation and 39 - 56% in the seven year old plantation. We applied this method in 2014 to a seven year old plantation, in Sarawak, Malaysia, modifying the method to include the heterotrophic contribution from beneath frond piles and weed covered areas. These results indicated peat based carbon losses to be 0.42 g CO2 m2 hr-1 [0.27;0.59] (equivalent to 37 t CO2 ha-1 yr-1 [24; 52]) at an average water table depth of 0.35 m, 47% of the measured

  15. Proteomic Changes Associated with Successive Reproductive Periods in Male Polychaetous Neanthes arenaceodentata

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Reish, Donald; Zhang, Huoming; Qian, Pei-Yuan; Ravasi, Timothy

    2015-01-01

    The polychaetous annelid Neanthes acuminata complex has a widespread distribution, with the California population referred to as N. arenaceodentata. The reproductive pattern in this complex is unique, in that the female reproduces once and then dies, whereas the male can reproduce up to nine times. The male incubates the embryos until the larvae leave the male’s tube 21–28 days later and commences feeding. Reproductive success and protein expression patterns were measured over the nine reproductive periods. The percent success of the male in producing juveniles increased during the first three reproductive periods and then decreased, but the number of juveniles produced was similar through all nine periods. iTRAQ based quantitative proteomics were used to analyze the dynamics of protein expression patterns. The expression patterns of several proteins were found to be altered. The abundant expression of muscular and contractile proteins may have affected body weight and reproductive success. Sperm have never been observed; fertilization occurs within the parent’s tube. Proteins associated with sperm maturation and fertilization were identified, including ATPase, clathrin, peroxiredoxins and enolase, which may provide clues to the molecular mechanisms enabling males to reproduce multiple times.

  16. Proteomic Changes Associated with Successive Reproductive Periods in Male Polychaetous Neanthes arenaceodentata

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2015-09-04

    The polychaetous annelid Neanthes acuminata complex has a widespread distribution, with the California population referred to as N. arenaceodentata. The reproductive pattern in this complex is unique, in that the female reproduces once and then dies, whereas the male can reproduce up to nine times. The male incubates the embryos until the larvae leave the male’s tube 21–28 days later and commences feeding. Reproductive success and protein expression patterns were measured over the nine reproductive periods. The percent success of the male in producing juveniles increased during the first three reproductive periods and then decreased, but the number of juveniles produced was similar through all nine periods. iTRAQ based quantitative proteomics were used to analyze the dynamics of protein expression patterns. The expression patterns of several proteins were found to be altered. The abundant expression of muscular and contractile proteins may have affected body weight and reproductive success. Sperm have never been observed; fertilization occurs within the parent’s tube. Proteins associated with sperm maturation and fertilization were identified, including ATPase, clathrin, peroxiredoxins and enolase, which may provide clues to the molecular mechanisms enabling males to reproduce multiple times.

  17. Nitrate removal from groundwater by cooperating heterotrophic with autotrophic denitrification in a biofilm-electrode reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yingxin [School of Water Resources and Environment, China University of Geosciences, Beijing 100083 (China); Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 3058572 (Japan); Feng, Chuanping, E-mail: fengchuangping@gmail.com [School of Water Resources and Environment, China University of Geosciences, Beijing 100083 (China); Wang, Qinghong; Yang, Yingnan; Zhang, Zhenya; Sugiura, Norio [Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 3058572 (Japan)

    2011-09-15

    Highlights: {yields} Intensified biofilm-electrode reactor using cooperative denitrification is developed. {yields} IBER combines heterotrophic and autotrophic denitrification. {yields} CO{sub 2} formed by heterotrophic denitrification is used by autotrophic bacteria. {yields} Optimum running conditions are C/N = 0.75, HRT = 8 h, and I = 40 mA. {yields} A novel degradation mechanism for cooperating denitrification process is proposed. - Abstract: An intensified biofilm-electrode reactor (IBER) combining heterotrophic and autotrophic denitrification was developed for treatment of nitrate contaminated groundwater. The reactor was evaluated with synthetic groundwater (NO{sub 3}{sup -}N50 mg L{sup -1}) under different hydraulic retention times (HRTs), carbon to nitrogen ratios (C/N) and electric currents (I). The experimental results demonstrate that high nitrate and nitrite removal efficiency (100%) were achieved at C/N = 1, HRT = 8 h, and I = 10 mA. C/N ratios were reduced from 1 to 0.5 and the applied electric current was changed from 10 to 100 mA, showing that the optimum running condition was C/N = 0.75 and I = 40 mA, under which over 97% of NO{sub 3}{sup -}N was removed and organic carbon (methanol) was completely consumed in treated water. Simultaneously, the denitrification mechanism in this system was analyzed through pH variation in effluent. The CO{sub 2} produced from the anode acted as a good pH buffer, automatically controlling pH in the reaction zone. The intensified biofilm-electrode reactor developed in the study was effective for the treatment of groundwater polluted by nitrate.

  18. Toxic effects and bioaccumulation of nano-, micron- and ionic-Ag in the polychaete, Nereis diversicolor

    DEFF Research Database (Denmark)

    cong, Yi; Banta, Gary Thomas; Selck, Henriette

    There is increasing concern about the toxicities and potential risks, both still poorly understood, of silver nanoparticles for the aquatic environment after their eventual release. In this study, the toxicities of nano (AgNO3)-Ag on the sediment......-dwelling polychaete, Nereis diversicolor, were compared after 10 d of sediment exposure, using growth, DNA damage (comet assay) and bioaccumulation as endpoints. The nominal concentrations used in all exposure scenarios were 0, 1, 5, 10, 25, 50 µg Ag/g dry weight (dw) sediment. Our results show that Ag is able...... to cause DNA damage in Nereis coelomocytes and that this effect is both concentration- and Ag form-related. There were significantly greater genotoxity (higher tail moment and tail DNA intensities) at 25 and 50 µg/g dw in nano- and micron-Ag treated groups and at 50 µg/g dw in ionic-Ag treated group...

  19. [Identification and Nitrogen Removal Characteristics of a Heterotrophic Nitrification-Aerobic Denitrification Strain Isolated from Marine Environment].

    Science.gov (United States)

    Sun, Qing-hua; Yu, De-shuang; Zhang, Pei-yu; Lin, Xue-zheng; Li, Jin

    2016-02-15

    A heterotrophic nitrification-aerobic denitrification strain named y5 was isolated from marine environment by traditional microbial isolation method using seawater as medium. It was identified as Klebsiella sp. based on the morphological, physiological and 16S rRNA sequence analysis. The experiment results showed that the optimal carbon resource was sodium citrate; the optimal pH was 7.0; and the optimal C/N was 17. The strain could use NH4Cl, NaNO2 and KNO3 as sole nitrogen source, and the removal efficiencies were77.07%, 64.14% and 100% after 36 hours, respectively. The removal efficiency reached 100% after 36 hours in the coexistence of NH4Cl, NaNO2 and KNO3. The results showed that the strain y5 had independent and efficient heterotrophic nitrification and aerobic denitrification activities in high salt wastewater.

  20. Massive occurrence of heterotrophic filaments in acidified lakes: seasonal dynamics and composition

    Czech Academy of Sciences Publication Activity Database

    Vrba, Jaroslav; Nedoma, Jiří; Kohout, L.; Kopáček, Jiří; Nedbalová, L.; Ráčková, P.; Šimek, Karel

    2003-01-01

    Roč. 46, č. 3 (2003), s. 281-294 ISSN 0168-6496 R&D Projects: GA ČR GA206/97/0072; GA ČR GA206/00/0063; GA ČR GA206/03/1583; GA AV ČR IAA6017202; GA AV ČR IPP1011802 Institutional research plan: CEZ:AV0Z6017912 Keywords : bacterioplankton * phylogenetic identification * heterotrophic filaments Subject RIV: EE - Microbiology, Virology Impact factor: 2.947, year: 2003

  1. The relative importance of water and diet for uptake and subcellular distribution of cadmium in the deposit-feeding polychaete, Capitella sp I

    DEFF Research Database (Denmark)

    Selck, Henriette; Forbes, Valery E.

    2004-01-01

    The impact of dietary and water exposure on the accumulation and distribution of cadmium (Cd) in subcellular components of the polychaete Capitella sp. I was investigated. Worms were exposed to either dissolved Cd alone ('Water-Only' treatments; WO) or diet-bound Cd alone ('Algae-bound Only......, starvation likewise influenced the distribution of protein between mitochondria and cytosol. Cutaneous uptake and accumulation of Cd from the water was related to surface area while dietary uptake was influenced by the amount of sediment passing through the gut. Irrespective of exposure route, Cd...

  2. Biodiversity of culturable heterotrophic bacteria in the Southern Adriatic Sea Italian coastal waters

    Directory of Open Access Journals (Sweden)

    Loredana Stabili

    2004-04-01

    Full Text Available The qualitative and quantitative composition of culturable heterotrophic bacteria in water samples from the Southern Adriatic Sea of Italy was examined. Water samples were collected monthly, for a year, at 16 stations along the coast line between Brindisi and Santa Maria di Leuca. The results obtained described the heterotrophic bacterial community over an annual cycle. Mean values of bacterial densities were 5.3 x 104 CFUml-1 in Brindisi, 5.8 x 104 CFUml-1 in S. Cataldo, 4.3 x 104 CFUml-1 in Otranto and 6.7 x 104 CFUml-1 in S. M. di Leuca. The differences in bacterial densities between the sites considered were estimated. The hydrodynamic circulation, the trophism and the geographical position of the examined sites contribute to justify the different bacterial density trends. The bacterial community consisted mainly of the genera Aeromonas, Pseudomonas, Photobacterium and Flavobacterium. The Enterobacteriaceae represented a considerable fraction of the bacterial community in the Southern Adriatic Sea. Bacilli were predominant among the Gram positive bacteria. The enzymatic versatility of the observed genera suggest their importance in organic matter turnover of this oligotrophic ecosystem.

  3. Photosynthetic and Heterotrophic Ferredoxin Isoproteins Are Colocalized in Fruit Plastids of Tomato1

    Science.gov (United States)

    Aoki, Koh; Yamamoto, Miyuki; Wada, Keishiro

    1998-01-01

    Fruit tissues of tomato (Lycopersicon esculentum Mill.) contain both photosynthetic and heterotrophic ferredoxin (FdA and FdE, respectively) isoproteins, irrespective of their photosynthetic competence, but we did not previously determine whether these proteins were colocalized in the same plastids. In isolated fruit chloroplasts and chromoplasts, both FdA and FdE were detected by immunoblotting. Colocalization of FdA and FdE in the same plastids was demonstrated using double-staining immunofluorescence microscopy. We also found that FdA and FdE were colocalized in fruit chloroplasts and chloroamyloplasts irrespective of sink status of the plastid. Immunoelectron microscopy demonstrated that FdA and FdE were randomly distributed within the plastid stroma. To investigate the significance of the heterotrophic Fd in fruit plastids, Glucose 6-phosphate dehydrogenase (G6PDH) activity was measured in isolated fruit and leaf plastids. Fruit chloroplasts and chromoplasts showed much higher G6PDH activity than did leaf chloroplasts, suggesting that high G6PDH activity is linked with FdE to maintain nonphotosynthetic production of reducing power. This result suggested that, despite their morphological resemblance, fruit chloroplasts are functionally different from their leaf counterparts. PMID:9765529

  4. Diffusive fractionation complicates isotopic partitioning of autotrophic and heterotrophic sources of soil respiration.

    Science.gov (United States)

    Moyes, Andrew B; Gaines, Sarah J; Siegwolf, Rolf T W; Bowling, David R

    2010-11-01

    Carbon isotope ratios (δ¹³C) of heterotrophic and rhizospheric sources of soil respiration under deciduous trees were evaluated over two growing seasons. Fluxes and δ¹³C of soil respiratory CO₂ on trenched and untrenched plots were calculated from closed chambers, profiles of soil CO₂ mole fraction and δ¹³C and continuous open chambers. δ¹³C of respired CO₂ and bulk carbon were measured from excised leaves and roots and sieved soil cores. Large diel variations (>5‰) in δ¹³C of soil respiration were observed when diel flux variability was large relative to average daily fluxes, independent of trenching. Soil gas transport modelling supported the conclusion that diel surface flux δ¹³C variation was driven by non-steady state gas transport effects. Active roots were associated with high summertime soil respiration rates and around 1‰ enrichment in the daily average δ¹³C of the soil surface CO₂ flux. Seasonal δ¹³C variability of about 4‰ (most enriched in summer) was observed on all plots and attributed to the heterotrophic CO₂ source. © 2010 Blackwell Publishing Ltd.

  5. Genomics and ecophysiology of heterotrophic nitrogen fixing bacteria isolated from estuarine surface water

    DEFF Research Database (Denmark)

    Bentzon-Tilia, Mikkel; Severin, Ina; Hansen, Lars H.

    2015-01-01

    The ability to reduce atmospheric nitrogen (N2) to ammonia, known as N2 fixation, is a widely distributed trait among prokaryotes that accounts for an essential input of new N to a multitude of environments. Nitrogenase reductase gene (nifH) composition suggests that putative N2-fixing heterotrop......The ability to reduce atmospheric nitrogen (N2) to ammonia, known as N2 fixation, is a widely distributed trait among prokaryotes that accounts for an essential input of new N to a multitude of environments. Nitrogenase reductase gene (nifH) composition suggests that putative N2-fixing...... heterotrophic organisms are widespread in marine bacterioplankton, but their autecology and ecological significance are unknown. Here, we report genomic and ecophysiology data in relation to N2 fixation by three environmentally relevant heterotrophic bacteria isolated from Baltic Sea surface water: Pseudomonas...... liter-1, presumably accommodated through aggregate formation. Glucose stimulated N2 fixation in general, and reactive N repressed N2 fixation, except that ammonium (NH4 ) stimulated N2 fixation in R. palustris BAL398, indicating the use of nitrogenase as an electron sink. The lack of correlations...

  6. New Insights on the Ecology of Free-living, Heterotrophic Nanoflagellates Based on the Use of Molecular Biological Approaches

    National Research Council Canada - National Science Library

    Lim, Lin

    1997-01-01

    .... Restriction fragment length polymorphism (RFLP) analysis of small subunit rDNA differentiated cultures of heterotrophic nanoflagellates according to established taxonomic classification at the generic and species level...

  7. Enhanced lipid accumulation and biodiesel production by oleaginous Chlorella protothecoides under a structured heterotrophic-iron (II) induction strategy.

    Science.gov (United States)

    Li, Yuqin; Mu, Jinxiu; Chen, Di; Xu, Hua; Han, Fangxin

    2015-05-01

    A structured heterotrophic-iron (II) induction (HII) strategy was proposed to enhance lipid accumulation in oleaginous Chlorella protothecoides. C. protothecoides subjected to heterotrophic-iron (II) induction achieved a favorable lipid accumulation up to 62 % and a maximum lipid productivity of 820.17 mg/day, representing 2.78-fold and 3.64-fold increase respectively over heterotrophic cultivation alone. HII-induced cells produced significantly elevated levels of 16:0, 18:1(Δ9), and 18:2(Δ9,12) fatty acids (over 90 %). The lipid contents and plant lipid-like fatty acid compositions exhibit the potential of HII-induced C. protothecoides as biodiesel feedstock. Furthermore, 31 altered proteins in HII-induced algal cells were successfully identified. These differentially expressed proteins were assigned into nine molecular function categories, including carbohydrate metabolism, lipid biosynthesis, Calvin cycle, cellular respiration, photosynthesis, energy and transport, protein biosynthesis, regulate and defense, and unclassified. Analysis using the Kyoto encyclopedia of genes and genomes and gene ontology annotation showed that malic enzyme, acyltransferase, and ACP were key metabolic checkpoints found to modulate lipid accumulation in C. protothecoides. The results provided possible applications of HII cultivation strategy in other microalgal species and new possibilities in developing genetic and metabolic engineering microalgae for desirable lipid productivity.

  8. Characterization of culturable heterotrophic bacteria in hydrocarbon-contaminated soil from an alpine former military site.

    Science.gov (United States)

    Zhang, Dechao; Margesin, Rosa

    2014-06-01

    We characterized the culturable, heterotrophic bacterial community in soil collected from a former alpine military site contaminated with petroleum hydrocarbons. The physiologically active eubacterial community, as revealed by fluorescence-in situ-hybridization, accounted for 14.9 % of the total (DAPI-stained) bacterial community. 4.0 and 1.2 % of the DAPI-stained cells could be attributed to culturable, heterotrophic bacteria able to grow at 20 and 10 °C, respectively. The majority of culturable bacterial isolates (23/28 strains) belonged to the Proteobacteria with a predominance of Alphaproteobacteria. The remaining isolates were affiliated with the Firmicutes, Actinobacteria and Bacteroidetes. Five strains could be identified as representatives of novel species. Characterization of the 28 strains demonstrated their adaptation to the temperature and nutrient conditions prevailing in the studied soil. One-third of the strains was able to grow at subzero temperatures (-5 °C). Studies on the effect of temperature on growth and lipase production with two selected strains demonstrated their low-temperature adaptation.

  9. Growth rate characteristics of acidophilic heterotrophic organisms from mine waste rock piles

    Science.gov (United States)

    Yacob, T. W.; Silverstein, J.; Jenkins, J.; Andre, B. J.; Rajaram, H.

    2010-12-01

    Autotrophic iron oxidizing bacteria play a key role in pyrite oxidation and generation of acid mine drainage AMD. Scarcity of organic substrates in many disturbed sites insures that IOB have sufficient oxygen and other nutrients for growth. It is proposed that addition of organic carbon substrate to waste rock piles will result in enrichment of heterotrophic microorganisms limiting the role of IOB in AMD generation. Previous researchers have used the acidophilic heterotroph Acidiphilium cryptum as a model to study the effects of organic substrate addition on the pyrite oxidation/AMD cycle. In order to develop a quantitative model of effects such as competition for oxygen, it is necessary to use growth and substrate consumption rate expressions, and one approach is to choose a model strain such as A. cryptum for kinetic studies. However we have found that the growth rate characteristics of A. cryptum may not provide an accurate model of the remediation effects of organic addition to subsurface mined sites. Fluorescent in-situ hybridization (FISH) assays of extracts of mine waste rock enriched with glucose and yeast extract did not produce countable numbers of cells in the Acidiphilium genus, with a detection limit of3 x 104 cells/gram rock, despite evidence of the presence of well established heterotrophic organisms. However, an MPN enrichment produced heterotrophic population estimates of 1x107 and 1x109 cells/gram rock. Growth rate studies of A. cryptum showed that cultures took 120 hours to degrade 50% of an initial glucose concentration of 2,000 mg/L. However a mixed culture enriched from mine waste rock consumed 100% of the same amount of glucose in 24 hours. Substrate consumption data for the mixed culture were fit to a Monod growth model: {dS}/{dt} = μ_{max}S {( {X_0}/{Y} + S_0 -S )}/{(K_s +S)} Kinetic parameters were estimated utilizing a non linear regression method coupled with an ODE solver. The maximum specific growth rate of the mixed population with

  10. Deterioration study of a material for encapsulation of radioactive wastes, the Portland cement, by heterotrophic microorganisms isolated from natural media

    International Nuclear Information System (INIS)

    Perfettini, J.

    1989-01-01

    Soils and geologic formations selected for storage of radioactive waste storage contain microflora (nitrifying and sulfoxidizing bacteria, heterotrophic microorganisms) that can corrode cement through acidic metabolism products. Nutriments required for their development are also found in these biotopes. Corrosine effects of organic acids produced by heterotrophic microorganisms are: mass decrease, leaching (especially Ca), dissolution of portlandite crystals Ca (OH) 2 , increase of porosity and decrease of flexural strength. Excretion of corrosive organic acids by bacteria is promoted by high temperature and basic pH. Acidification by fungi requires also a high temperature but an acidic pH [fr

  11. Biodiversity on the Rocks: Macrofauna Inhabiting Authigenic Carbonate at Costa Rica Methane Seeps.

    Directory of Open Access Journals (Sweden)

    Lisa A Levin

    Full Text Available Carbonate communities: The activity of anaerobic methane oxidizing microbes facilitates precipitation of vast quantities of authigenic carbonate at methane seeps. Here we demonstrate the significant role of carbonate rocks in promoting diversity by providing unique habitat and food resources for macrofaunal assemblages at seeps on the Costa Rica margin (400-1850 m. The attendant fauna is surprisingly similar to that in rocky intertidal shores, with numerous grazing gastropods (limpets and snails as dominant taxa. However, the community feeds upon seep-associated microbes. Macrofaunal density, composition, and diversity on carbonates vary as a function of seepage activity, biogenic habitat and location. The macrofaunal community of carbonates at non-seeping (inactive sites is strongly related to the hydrography (depth, temperature, O2 of overlying water, whereas the fauna at sites of active seepage is not. Densities are highest on active rocks from tubeworm bushes and mussel beds, particularly at the Mound 12 location (1000 m. Species diversity is higher on rocks exposed to active seepage, with multiple species of gastropods and polychaetes dominant, while crustaceans, cnidarians, and ophiuroids were better represented on rocks at inactive sites. Macro-infauna (larger than 0.3 mm from tube cores taken in nearby seep sediments at comparable depths exhibited densities similar to those on carbonate rocks, but had lower diversity and different taxonomic composition. Seep sediments had higher densities of ampharetid, dorvilleid, hesionid, cirratulid and lacydoniid polychaetes, whereas carbonates had more gastropods, as well as syllid, chrysopetalid and polynoid polychaetes. Stable isotope signatures and metrics: The stable isotope signatures of carbonates were heterogeneous, as were the food sources and nutrition used by the animals. Carbonate δ13Cinorg values (mean = -26.98‰ ranged from -53.3‰ to +10.0‰, and were significantly heavier than

  12. The biogenic reefs formed by the alien polychaete Hydroides dianthus (Serpulidae, Annelida) favor the polyp stage of Aurelia coerulea (Cnidaria, Scyphozoa) in a coastal artificial lake.

    Science.gov (United States)

    Dong, Zhijun; Sun, Tingting; Wang, Lei

    2018-04-01

    Blooms of the moon jellyfish Aurelia coerulea frequently occur in coastal waters. The increased availability of substrates for the settlement and proliferation of polyps due to the expansion of artificial structures in coastal areas has been proposed as a possible contributing factor in jellyfish blooms. This paper investigates whether a marine artificial lake (Fenghuang Lake) provides additional substrates for A. coerulea polyps and contributes to jellyfish blooms. High densities of A. coerulea ephyrae were discovered in this lake, with a mean density of 41 individuals/m 3 and a maximum measured density of 128 individuals/m 3 . Meanwhile, A. coerulea ephyrae were also found in the two emptying channels outside the lake, with a mean density of 13 individuals/m 3 . Underwater surveys revealed that dense colonies of A. coerulea polyps occurred mainly on biogenic reefs formed by a polychaete, which was identified as an invasive serpulid species Hydroides dianthus, based on the phylogenetic analysis of mitochondrial COI gene sequences. Our study highlights the potential modification of habitats by the alien polychaete H. dianthus, which might provide complex benthic habits suitable for the settlement and proliferation of A. coerulea polyps and may contribute to jellyfish blooms in the marine artificial lake and nearby coastal waters. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Modeling pure culture heterotrophic production of polyhydroxybutyrate (PHB).

    Science.gov (United States)

    Mozumder, Md Salatul Islam; Goormachtigh, Laurens; Garcia-Gonzalez, Linsey; De Wever, Heleen; Volcke, Eveline I P

    2014-03-01

    In this contribution a mechanistic model describing the production of polyhydroxybutyrate (PHB) through pure-culture fermentation was developed, calibrated and validated for two different substrates, namely glucose and waste glycerol. In both cases, non-growth-associated PHB production was triggered by applying nitrogen limitation. The occurrence of some growth-associated PHB production besides non-growth-associated PHB production was demonstrated, although it is inhibited in the presence of nitrogen. Other phenomena observed experimentally and described by the model included biomass growth on PHB and non-linear product inhibition of PHB production. The accumulated impurities from the waste substrate negatively affected the obtained maximum PHB content. Overall, the developed mathematical model provided an accurate prediction of the dynamic behavior of heterotrophic biomass growth and PHB production in a two-phase pure culture system. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Self-sustaining, solar-driven bioelectricity generation in micro-sized microbial fuel cell using co-culture of heterotrophic and photosynthetic bacteria

    Science.gov (United States)

    Liu, Lin; Choi, Seokheun

    2017-04-01

    Among many energy harvesting techniques with great potential, microbial fuel cell (MFC) technology is arguably the most underdeveloped. Even so, excitement is building, as microorganisms can harvest electrical power from any biodegradable organic source (e.g. wastewater) that is readily available in resource-limited settings. Nevertheless, the requirement for endless introduction of organic matter imposes a limiting factor to this technology, demanding an active feeding system and additional power. Here, we demonstrated self-sustaining bioelectricity generation from a microliter-scale microbial fuel cell (MFC) by using the syntrophic interaction between heterotrophic exoelectrogenic bacteria and phototrophs. The MFC continuously generated light-responsive electricity from the heterotrophic bacterial metabolic respiration with the organic substrates produced by photosynthetic bacteria. Without additional organic fuel, the mixed culture in a 90-μL-chamber MFC generated self-sustained current for more than 13 days, while the heterotrophic culture produced current that decreased dramatically within a few hours. The current from the mixed culture was about 70 times greater than that of the device with only photosynthetic bacteria. The miniaturization provided a short start-up time, a well-controlled environment, and small internal resistance. Those advantages will become the general design platform for micropower generation.

  15. Heterotrophs are key contributors to nitrous oxide production in activated sludge under low C-to-N ratios during nitrification-Batch experiments and modeling.

    Science.gov (United States)

    Domingo-Félez, Carlos; Pellicer-Nàcher, Carles; Petersen, Morten S; Jensen, Marlene M; Plósz, Benedek G; Smets, Barth F

    2017-01-01

    Nitrous oxide (N 2 O), a by-product of biological nitrogen removal during wastewater treatment, is produced by ammonia-oxidizing bacteria (AOB) and heterotrophic denitrifying bacteria (HB). Mathematical models are used to predict N 2 O emissions, often including AOB as the main N 2 O producer. Several model structures have been proposed without consensus calibration procedures. Here, we present a new experimental design that was used to calibrate AOB-driven N 2 O dynamics of a mixed culture. Even though AOB activity was favoured with respect to HB, oxygen uptake rates indicated HB activity. Hence, rigorous experimental design for calibration of autotrophic N 2 O production from mixed cultures is essential. The proposed N 2 O production pathways were examined using five alternative process models confronted with experimental data inferred. Individually, the autotrophic and heterotrophic denitrification pathway could describe the observed data. In the best-fit model, which combined two denitrification pathways, the heterotrophic was stronger than the autotrophic contribution to N 2 O production. Importantly, the individual contribution of autotrophic and heterotrophic to the total N 2 O pool could not be unambiguously elucidated solely based on bulk N 2 O measurements. Data on NO would increase the practical identifiability of N 2 O production pathways. Biotechnol. Bioeng. 2017;114: 132-140. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  16. Impact of polychaetes (Nereis spp. and Arenicola marina on carbon biogeochemistry in coastal marine sediments†

    Directory of Open Access Journals (Sweden)

    Kristensen Erik

    2001-10-01

    Full Text Available Known effects of bioturbation by common polychaetes (Nereis spp. and Arenicola marina in Northern European coastal waters on sediment carbon diagenesis is summarized and assessed. The physical impact of irrigation and reworking activity of the involved polychaete species is evaluated and related to their basic biology. Based on past and present experimental work, it is concluded that effects of bioturbation on carbon diagenesis from manipulated laboratory experiments cannot be directly extrapolated to in situ conditions. The 45–260% flux (e.g., CO2 release enhancement found in the laboratory is much higher than usually observed in the field (10–25%. Thus, the faunal induced enhancement of microbial carbon oxidation in natural sediments instead causes a reduction of the organic matter inventory rather than an increased release of CO2 across the sediment/water interface. The relative decrease in organic inventory (Gb/Gu is inversely related to the relative increase in microbial capacity for organic matter decay (kb/ku. The equilibrium is controlled by the balance between organic input (deposition of organic matter at the sediment surface and the intensity of bioturbation. Introduction of oxygen to subsurface sediment and removal of metabolites are considered the two most important underlying mechanisms for the stimulation of carbon oxidation by burrowing fauna. Introduction of oxygen to deep sediment layers of low microbial activity, either by downward irrigation transport of overlying oxic water or by upward reworking transport of sediment to the oxic water column will increase carbon oxidation of anaerobically refractory organic matter. It appears that the irrigation effect is larger than and to a higher degree dependent on animal density than the reworking effect. Enhancement of anaerobic carbon oxidation by removal of metabolites (reduced diffusion scale may cause a significant increase in total sediment metabolism. This is caused by three

  17. Quantitative analysis of an engineered CO2-fixing Escherichia coli reveals great potential of heterotrophic CO2 fixation.

    Science.gov (United States)

    Gong, Fuyu; Liu, Guoxia; Zhai, Xiaoyun; Zhou, Jie; Cai, Zhen; Li, Yin

    2015-01-01

    Production of fuels from the abundant and wasteful CO2 is a promising approach to reduce carbon emission and consumption of fossil fuels. Autotrophic microbes naturally assimilate CO2 using energy from light, hydrogen, and/or sulfur. However, their slow growth rates call for investigation of the possibility of heterotrophic CO2 fixation. Although preliminary research has suggested that CO2 fixation in heterotrophic microbes is feasible after incorporation of a CO2-fixing bypass into the central carbon metabolic pathway, it remains unclear how much and how efficient that CO2 can be fixed by a heterotrophic microbe. A simple metabolic flux index was developed to indicate the relative strength of the CO2-fixation flux. When two sequential enzymes of the cyanobacterial Calvin cycle were incorporated into an E. coli strain, the flux of the CO2-fixing bypass pathway accounts for 13 % of that of the central carbon metabolic pathway. The value was increased to 17 % when the carbonic anhydrase involved in the cyanobacterial carbon concentrating mechanism was introduced, indicating that low intracellular CO2 concentration is one limiting factor for CO2 fixation in E. coli. The engineered CO2-fixing E. coli with carbonic anhydrase was able to fix CO2 at a rate of 19.6 mg CO2 L(-1) h(-1) or the specific rate of 22.5 mg CO2 g DCW(-1) h(-1). This CO2-fixation rate is comparable with the reported rates of 14 autotrophic cyanobacteria and algae (10.5-147.0 mg CO2 L(-1) h(-1) or the specific rates of 3.5-23.7 mg CO2 g DCW(-1) h(-1)). The ability of CO2 fixation was created and improved in E. coli by incorporating partial cyanobacterial Calvin cycle and carbon concentrating mechanism, respectively. Quantitative analysis revealed that the CO2-fixation rate of this strain is comparable with that of the autotrophic cyanobacteria and algae, demonstrating great potential of heterotrophic CO2 fixation.

  18. Decadal warming causes a consistent and persistent shift from heterotrophic to autotrophic respiration in contrasting permafrost ecosystems

    NARCIS (Netherlands)

    Hicks Pries, C.E.; van Logtestijn, R.S.P; Schuur, E.A.G.; Natali, S.M.; Cornelissen, J.H.C.; Aerts, R.; Dorrepaal, E.

    2015-01-01

    Soil carbon in permafrost ecosystems has the potential to become a major positive feedback to climate change if permafrost thaw increases heterotrophic decomposition. However, warming can also stimulate autotrophic production leading to increased ecosystem carbon storage-a negative climate change

  19. Developmental stages of fish blood flukes, Cardicola forsteri and Cardicola opisthorchis (Trematoda: Aporocotylidae), in their polychaete intermediate hosts collected at Pacific bluefin tuna culture sites in Japan.

    Science.gov (United States)

    Ogawa, Kazuo; Shirakashi, Sho; Tani, Kazuki; Shin, Sang Phil; Ishimaru, Katsuya; Honryo, Tomoki; Sugihara, Yukitaka; Uchida, Hiro'omi

    2017-02-01

    Farming of Pacific bluefin tuna (PBT), Thunnus orientalis, is a rapidly growing industry in Japan. Aporocotylid blood flukes of the genus Cardicola comprising C. orientalis, C. opisthorchis and C. forsteri are parasites of economic importance for PBT farming. Recently, terebellid polychaetes have been identified as the intermediate hosts for all these parasites. We collected infected polychaetes, Terebella sp., the intermediate host of C. opisthorchis, from ropes and floats attached to tuna cages in Tsushima, Nagasaki Prefecture, Japan. Also, Neoamphitrite vigintipes (formerly as Amphitrite sp. sensu Shirakashi et al., 2016), the intermediate host of C. forsteri, were collected from culture cages in Kushimoto, Wakayama Prefecture, Japan. The terebellid intermediate hosts harbored the sporocysts and cercariae in their body cavity. Developmental stages of these blood flukes were molecularly identified using species specific PCR primers. In this paper, we describe the cercaria and sporocyst stages of C. opisthorchis and C. forsteri and compare their morphological characteristics among three Cardicola blood flukes infecting PBT. We also discuss phylogenetic relations of the six genera of the terebellid intermediate hosts (Artacama, Lanassa, Longicarpus, Terebella, Nicolea and Neoamphitrite) of blood flukes infecting marine fishes, based on their morphological characters. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Effects of mercury contamination on the culturable heterotrophic, functional and genetic diversity of the bacterial community in soil

    DEFF Research Database (Denmark)

    Rasmussen, Lasse Dam; Sørensen, S. J.

    2001-01-01

    This study investigates the effect of mercury contamination on the culturable heterotrophic, functional and genetic diversity of the bacterial community in soil. The changes in diversity were monitored in soil microcosms, enriched with 25 mug Hg(II) g(-1) soil, over a period of 3 months...... by purification of total soil DNA and amplification of bacterial 16S rDNA fragments by polymerase chain reaction. Concentrations of bioavailable and total mercury were measured throughout the experiment. The effect on the culturable heterotrophic and genetic diversity was very similar, showing an immediate...... decrease after mercury addition but then slowly increasing throughout the entire experimental period. Pre-exposure levels were not reached within the time span of this investigation. The DGGE band pattern indicated that a shift in the community structure was responsible for recovered diversity. When...

  1. Antibiotic resistance in triclosan heterotrophic plate count bacteria from sewage water / Ilsé Coetzee

    OpenAIRE

    Coetzee, Ilsé

    2015-01-01

    The concentration of triclosan in antiseptics, disinfectants and preservatives in products exceeds the minimal lethal levels. Extensive use of triclosan and antibiotics results in bacterial resistance to their active ingredients. The precise relationship between use and resistance, however, has been challenging to define. The aim of the study was to identify and determine antibiotic resistance profiles of triclosan tolerant heterotrophic plate count bacteria isolates from sewag...

  2. Still acting green: continued expression of photosynthetic genes in the heterotrophic Dinoflagellate Pfiesteria piscicida (Peridiniales, Alveolata.

    Directory of Open Access Journals (Sweden)

    Gwang Hoon Kim

    Full Text Available The loss of photosynthetic function should lead to the cessation of expression and finally loss of photosynthetic genes in the new heterotroph. Dinoflagellates are known to have lost their photosynthetic ability several times. Dinoflagellates have also acquired photosynthesis from other organisms, either on a long-term basis or as "kleptoplastids" multiple times. The fate of photosynthetic gene expression in heterotrophs can be informative into evolution of gene expression patterns after functional loss, and the dinoflagellates ability to acquire new photosynthetic function through additional endosymbiosis. To explore this we analyzed a large-scale EST database consisting of 151,091 unique sequences (29,170 contigs, 120,921 singletons obtained from 454 pyrosequencing of the heterotrophic dinoflagellate Pfiesteria piscicida. About 597 contigs from P. piscicida showed significant homology (E-value

  3. Still acting green: continued expression of photosynthetic genes in the heterotrophic Dinoflagellate Pfiesteria piscicida (Peridiniales, Alveolata).

    Science.gov (United States)

    Kim, Gwang Hoon; Jeong, Hae Jin; Yoo, Yeong Du; Kim, Sunju; Han, Ji Hee; Han, Jong Won; Zuccarello, Giuseppe C

    2013-01-01

    The loss of photosynthetic function should lead to the cessation of expression and finally loss of photosynthetic genes in the new heterotroph. Dinoflagellates are known to have lost their photosynthetic ability several times. Dinoflagellates have also acquired photosynthesis from other organisms, either on a long-term basis or as "kleptoplastids" multiple times. The fate of photosynthetic gene expression in heterotrophs can be informative into evolution of gene expression patterns after functional loss, and the dinoflagellates ability to acquire new photosynthetic function through additional endosymbiosis. To explore this we analyzed a large-scale EST database consisting of 151,091 unique sequences (29,170 contigs, 120,921 singletons) obtained from 454 pyrosequencing of the heterotrophic dinoflagellate Pfiesteria piscicida. About 597 contigs from P. piscicida showed significant homology (E-value

  4. Laminaria digitata as potential carbon source in heterotrophic microalgae cultivation for the production of fish feed supplement

    DEFF Research Database (Denmark)

    D'Este, Martina; Alvarado-Morales, Merlin; Angelidaki, Irini

    2017-01-01

    A novel concept using the macroalgae Laminaria digitata as substrate to grow heterotrophically microalgae species to be used as fish feed supplement is investigated in the present study. Enzymatic hydrolysis of the macroalgae was performed to release the sugars present in the biomass. The hydroly......A novel concept using the macroalgae Laminaria digitata as substrate to grow heterotrophically microalgae species to be used as fish feed supplement is investigated in the present study. Enzymatic hydrolysis of the macroalgae was performed to release the sugars present in the biomass...... was selected for further cultivation in batch reactors and its protein content and amino acid composition were measured. At the end of the process the biomass production reached 10.68 ± 1.33 g L− 1with a total protein accumulation of 41.77 ± 1.82% (dry weight basis) and a protein yield of 0.17 ± 0.06. Moreover...

  5. Simulating soil N2O emissions and heterotrophic CO2 respiration in arabe systems using FASSET and MoBiLE-DNDC

    DEFF Research Database (Denmark)

    Chirinda, Ngonidzashe; Kracher, Daniele; Lægdsmand, Mette

    2011-01-01

    Modelling of soil emissions of nitrous oxide (N2O) and carbon dioxide (CO2) is complicated by complex interactions between processes and factors influencing their production, consumption and transport. In this study N2O emissions and heterotrophic CO2 respiration were simulated from soils under w...... mineral nitrogen, which seemed to originate from deficiencies in simulating degradation of soil organic matter, incorporated residues of catch crops and organic fertilizers. To improve the performance of the models, organic matter decomposition parameters need to be revised.......Modelling of soil emissions of nitrous oxide (N2O) and carbon dioxide (CO2) is complicated by complex interactions between processes and factors influencing their production, consumption and transport. In this study N2O emissions and heterotrophic CO2 respiration were simulated from soils under...... winter wheat grown in three different organic and one inorganic fertilizer-based cropping system using two different models, i.e., MoBiLE-DNDC and FASSET. The two models were generally capable of simulating most seasonal trends of measured soil heterotrophic CO2 respiration and N2O emissions. Annual soil...

  6. Seasonal and spatial variations in heterotrophic nanoflagellate and bacteria abundances in sediments of a freshwater littoral zone

    NARCIS (Netherlands)

    Starink, Mathieu; Bär-Gilissen, M.J.; Cappenberg, T.E.

    1996-01-01

    We studied seasonal variation in heterotrophic nanoflagellates (HNAN) and bacterial, densities at different depths in the sediment of two freshwater littoral stations. Station 1 was in a reed bed of Phragmites australis; station 2 was outside the reed zone in open water. Benthic HNAN abundances

  7. Autotrophic and heterotrophic activity in Arctic first-year sea-ice: Seasonal study from Marlene Bight, SW Greenland

    DEFF Research Database (Denmark)

    Søgaard, Dorte Haubjerg; Kristensen, Morten; Rysgaard, Søren

    2010-01-01

    in situ in plastic bags with subsequent melting and measurements of changes in total O-2 concentrations. The standard incubations showed that the annual succession followed a distinctive pattern, with a low, almost balancing heterotrophic and autotrophic activity during February and March. This period...

  8. The Effectiveness of Heterotrophic Bacteria Isolated from Dumai Marine Waters of Riau, Used as Antibacterial against Pathogens in Fish Culture

    Science.gov (United States)

    Feliatra, F.; Nursyirwani; Tanjung, A.; Adithiya, DS; Susanna, M.; Lukystyowati, I.

    2018-02-01

    Heterotrophic bacteria have an important role as decomposer of organic compounds (mineralization) derived from industrial waste, decomposition of unconsumed feed, faecal, excretion of fish, and have the ability to inhibit the growth of pathogenic bacteria. We investigated the role of heterotrophic bacteria used as antibacterial against pathogens in fish culture.This research was conducted from January until March 2017. The phylogenitic of the isolated bacterial was determined by 16S rDNA sequences analysis. Antagonism test showed that the bacteria had the ability to inhibit the growth of pathogenic bacteria (Vibrio alginolyticus, Aeromonas hydrophila and Pseudomonas sp.) Three isolates (Dm5, Dm6 and Dm4) indicated high inhibition zones which were classified into strong category with the average from 10.5 to 11.8 mm toward V. alginolitycus. Other isolates were classified into medium and weak category. Based on DNA analysis of heterotrophic bacteria isolated from marine waters of industrial area and low salinity of estuarine waters twelve strains of bacteria were identified, and all had highest level of homology to Bacillus sp.,one isolates has similarity to Enterobacter cloacae, other isolates to Clostridium cetobutylicum. Most of isolated bacteria obtained from the waters of industrial area due to it received much of nutrients that very influenced the growth of bacteria.

  9. Dynamics of auto- and heterotrophic picoplankton and associated viruses in Lake Geneva.

    Digital Repository Service at National Institute of Oceanography (India)

    Parvathi, A.; Zhong, X.; Ram, A.S.P.; Jacquet, S.

    Hydrol. Earth Syst. Sci., 18, 1073–1087, 2014 www.hydrol-earth-syst-sci.net/18/1073/2014/ doi:10.5194/hess-18-1073-2014 © Author(s) 2014. CC Attribution 3.0 License. Hydrology and Earth System Sciences O pen A ccess Dynamics of auto- and heterotrophic... Commission for the Protection of Lake Geneva (see reports at http://www.cipel.org/sp/), in order to study the water quality, functioning and evolution of this ecosys- tem, which is connected to an important catchment area. The detailed analysis of the viral...

  10. Biodynamic modelling and the prediction of accumulated trace metal concentrations in the polychaete Arenicola marina

    International Nuclear Information System (INIS)

    Casado-Martinez, M. Carmen; Smith, Brian D.; DelValls, T. Angel; Luoma, Samuel N.; Rainbow, Philip S.

    2009-01-01

    The use of biodynamic models to understand metal uptake directly from sediments by deposit-feeding organisms still represents a special challenge. In this study, accumulated concentrations of Cd, Zn and Ag predicted by biodynamic modelling in the lugworm Arenicola marina have been compared to measured concentrations in field populations in several UK estuaries. The biodynamic model predicted accumulated field Cd concentrations remarkably accurately, and predicted bioaccumulated Ag concentrations were in the range of those measured in lugworms collected from the field. For Zn the model showed less but still good comparability, accurately predicting Zn bioaccumulation in A. marina at high sediment concentrations but underestimating accumulated Zn in the worms from sites with low and intermediate levels of Zn sediment contamination. Therefore, it appears that the physiological parameters experimentally derived for A. marina are applicable to the conditions encountered in these environments and that the assumptions made in the model are plausible. - Biodynamic modelling predicts accumulated field concentrations of Ag, Cd and Zn in the deposit-feeding polychaete Arenicola marina.

  11. Sediment-worm interaction: transfer of 65Zn from marine silt by the polychaete, Nereis diversicolor

    International Nuclear Information System (INIS)

    Renfro, W.C.; Benayoun, G.

    1976-01-01

    Marine polychaete worms (Nereis diversicolor) accumulated 65 Zn sorbed to silty marine sediment for 5 days and were then transferred to nonradioactive sediment in the laboratory and in the sea. The mean biological half-life (T/sub B//2/) for the laboratory worms did not differ greatly from that for worms in the sea. Worms living in small flowing seawater systems containing 16 cm 3 of sediment accumulated 65 Zn added to each system in the form of radioactive organic detritus. Higher percentage uptake of 65 Zn was from radioactive detritus particles 0.2 to 2 mm in diameter resting on the sediment surface or mixed with sediment than from finely-ground ( 65 Zn coprecipitated from fresh water with Fe(OH) 3 was accumulated by N. diversicolor when the precipitate was on the sediment surface than when the precipitate was well mixed with the sediment. These experimental results indicate that benthic organisms may take up limited amounts of heavy metals associated with bottom sediments and recycle them to benthic and pelagic food webs

  12. Growth strategy of heterotrophic bacterial population along successional sequence on spoil of brown coal colliery substrate

    Czech Academy of Sciences Publication Activity Database

    Krištůfek, Václav; Elhottová, Dana; Chroňáková, Alica; Dostálková, I.; Picek, T.; Kalčík, Jiří

    2005-01-01

    Roč. 50, č. 5 (2005), s. 427-435 ISSN 0015-5632 R&D Projects: GA ČR(CZ) GA526/03/1259 Institutional research plan: CEZ:AV0Z60660521 Keywords : growth strategy * heterotrophic bacterial population * brown coal colliery spoil Subject RIV: EH - Ecology, Behaviour Impact factor: 0.918, year: 2005

  13. Physiological and biochemical responses of two keystone polychaete species: Diopatra neapolitana and Hediste diversicolor to Multi-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    De Marchi, Lucia [Departamento de Biologia & CESAM, University of Aveiro, 3810-193 (Portugal); Center for Mechanical Technology and Automation (TEMA), University of Aveiro, 3810-193 (Portugal); Neto, Victor [Center for Mechanical Technology and Automation (TEMA), University of Aveiro, 3810-193 (Portugal); Pretti, Carlo [Department of Veterinary Sciences, University of Pisa, San Piero a Grado, PI 56122 (Italy); Figueira, Etelvina [Departamento de Biologia & CESAM, University of Aveiro, 3810-193 (Portugal); Chiellini, Federica [Department of Chemistry and Industrial Chemistry, University of Pisa, Pisa 56126 (Italy); Soares, Amadeu M.V.M. [Departamento de Biologia & CESAM, University of Aveiro, 3810-193 (Portugal); Freitas, Rosa, E-mail: rosafreitas@ua.pt [Departamento de Biologia & CESAM, University of Aveiro, 3810-193 (Portugal)

    2017-04-15

    Multi-walled carbon nanotubes (MWCNTs) are one of the most important carbon Nanomaterials (NMs). The production and use of these carbon NMs is increasing rapidly and, therefore, the need to assess their presence in the environment and associated risks has become increasingly important. However, limited literature is available regarding the impacts induced in aquatic organisms by this pollutant, namely in invertebrate species. Diopatra neapolitana and Hediste diversicolor are keystone polychaete species inhabiting estuaries and shallow water bodies intertidal mudflats, frequently used to evaluate the impact of environmental disturbances in these systems. To our knowledge, no information is available on physiological and biochemical alterations on these two species due to MWCNTs exposure. Thus, the present study aimed to assess the toxic effects of different MWCNTs concentrations (0.01; 0.10 and 1.00 mg/L) in both species physiological (regenerative capacity and respiration rate) and biochemical (energy reserves, metabolic activities, oxidative stress related biomarkers and neurotoxicity markers) performance, after 28 days of exposure. The results obtained revealed that exposure to MWCNTs induced negative effects on the regenerative capacity of D. neapolitana. Additionally, higher MWCNTs concentrations induced increased respiration rates in D. neapolitana. MWCNTs altered energy-related responses, with higher values of electron transport system activity, glycogen and protein concentrations in both polychaetes exposed to this contaminant. Furthermore, when exposed to MWCNTs both species showed oxidative stress with higher lipid peroxidation, lower ratio between reduced and oxidized glutathione, and higher activity of antioxidant (catalase and superoxide dismutase) and biotransformation (glutathione-S-transferases) enzymes in exposed organisms. - Highlights: • MWCNTs induced negative effects on the regenerative capacity of Diopatra neapolitana. • Diopatra

  14. Decoupling of cadmium biokinetics and metallothionein turnover in a marine polychaete after metal exposure

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Tania Y.-T. [Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong (China); Rainbow, Philip S. [Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Amiard-Triquet, Claude; Amiard, Jean-Claude [Universite de Nantes, Faculte de Pharmacie, MMS EA2160, Service d' ecotoxicologie, F-44000 Nantes (France); Wang Wenxiong [Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong (China)], E-mail: wwang@ust.hk

    2008-08-11

    This study investigated the kinetics of Cd bioaccumulation, detoxification, subcellular distribution, and efflux in the nereid polychaete Perinereis aibuhitensis after Cd pre-exposure. Cd pre-exposure increased the Cd body burden in the worms, but did not affect the overall Cd uptake and efflux rates and metallothionein-like protein (MTLP) concentrations. During short-term exposure to dissolved Cd, Cd in the cytosolic fraction increased after Cd pre-exposure, and this fraction also increased during the Cd efflux period, indicating that the insoluble fraction of Cd was presumably lost at a faster rate than the loss of cytosolic Cd. Even though the MTLP concentration remained comparable after Cd pre-exposure, both the MTLP synthesis rate and the degradation rate increased, thus leading to a high MTLP turnover in the Cd-exposed worms. However, Cd uptake and efflux into different protein size fractions did not follow the patterns of MTLP synthesis and degradation, strongly suggesting that Cd kinetics is decoupled from the MTLP kinetics in the worms. Our study adds to an increasing body of evidence on the complicated relationship between metal biokinetics and MTLP kinetics in different groups of marine invertebrates which have strong contrasts in their metal handling strategies.

  15. Decoupling of cadmium biokinetics and metallothionein turnover in a marine polychaete after metal exposure

    International Nuclear Information System (INIS)

    Ng, Tania Y.-T.; Rainbow, Philip S.; Amiard-Triquet, Claude; Amiard, Jean-Claude; Wang Wenxiong

    2008-01-01

    This study investigated the kinetics of Cd bioaccumulation, detoxification, subcellular distribution, and efflux in the nereid polychaete Perinereis aibuhitensis after Cd pre-exposure. Cd pre-exposure increased the Cd body burden in the worms, but did not affect the overall Cd uptake and efflux rates and metallothionein-like protein (MTLP) concentrations. During short-term exposure to dissolved Cd, Cd in the cytosolic fraction increased after Cd pre-exposure, and this fraction also increased during the Cd efflux period, indicating that the insoluble fraction of Cd was presumably lost at a faster rate than the loss of cytosolic Cd. Even though the MTLP concentration remained comparable after Cd pre-exposure, both the MTLP synthesis rate and the degradation rate increased, thus leading to a high MTLP turnover in the Cd-exposed worms. However, Cd uptake and efflux into different protein size fractions did not follow the patterns of MTLP synthesis and degradation, strongly suggesting that Cd kinetics is decoupled from the MTLP kinetics in the worms. Our study adds to an increasing body of evidence on the complicated relationship between metal biokinetics and MTLP kinetics in different groups of marine invertebrates which have strong contrasts in their metal handling strategies

  16. Seasonal variation in population density and heterotrophic activity of attached and free-living bacteria in coastal waters

    International Nuclear Information System (INIS)

    Iriberri, J.; Unanue, M.; Barcina, I.; Egea, L.

    1987-01-01

    The abundance and heterotrophic activity of attached and free-living bacteria was examined seasonally in coastal water. Heterotrophic activity was determined by the uptake of [ 14 C]glucose. The density of attached bacteria was always minor, not showing a seasonal variation, whereas the free-living bacteria were more numerous and showed a marked seasonal variation, their density being higher under warmer conditions. The contribution of the attached bacteria to the total assimilation of [ 14 C]glucose was lower than that of the free-living bacteria, neither of them showing a seasonal variation. On a cellular basis, attached bacteria were more active, since they assimilated more [ 14 C]glucose and showed, under warmer conditions, a higher cellular volume. The authors consider that the factors responsible for these observations were the amount and quality of the particulate material, the different availability of organic matter for the two types of bacteria, and in a fundamental way, the variation in water temperature

  17. Simultaneous heterotrophic and sulfur-oxidizing autotrophic denitrification process for drinking water treatment: control of sulfate production.

    Science.gov (United States)

    Sahinkaya, Erkan; Dursun, Nesrin; Kilic, Adem; Demirel, Sevgi; Uyanik, Sinan; Cinar, Ozer

    2011-12-15

    A long-term performance of a packed-bed bioreactor containing sulfur and limestone was evaluated for the denitrification of drinking water. Autotrophic denitrification rate was limited by the slow dissolution rate of sulfur and limestone. Dissolution of limestone for alkalinity supplementation increased hardness due to release of Ca(2+). Sulfate production is the main disadvantage of the sulfur autotrophic denitrification process. The effluent sulfate concentration was reduced to values below drinking water guidelines by stimulating the simultaneous heterotrophic and autotrophic denitrification with methanol supplementation. Complete removal of 75 mg/L NO(3)-N with effluent sulfate concentration of around 225 mg/L was achieved when methanol was supplemented at methanol/NO(3)-N ratio of 1.67 (mg/mg), which was much lower than the theoretical value of 2.47 for heterotrophic denitrification. Batch studies showed that sulfur-based autotrophic NO(2)-N reduction rate was around three times lower than the reduction rate of NO(3)-N, which led to NO(2)-N accumulation at high loadings. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. A population of giant tailed virus-like particles associated with heterotrophic flagellates in a lake-type reservoir

    Czech Academy of Sciences Publication Activity Database

    Weinbauer, M.G.; Dolan, J. R.; Šimek, Karel

    2015-01-01

    Roč. 76, č. 2 (2015), s. 111-116 ISSN 0948-3055 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : viral infection * virus induced mortality * burst size * heterotrophic flagellates Subject RIV: EE - Microbiology, Virology Impact factor: 2.109, year: 2015

  19. Hidden in the crowd: primordial germ cells and somatic stem cells in the mesodermal posterior growth zone of the polychaete Platynereis dumerillii are two distinct cell populations

    Directory of Open Access Journals (Sweden)

    Rebscher Nicole

    2012-04-01

    Full Text Available Abstract Background In the polychaete Platynereis, the primordial germ cells (PGCs emerge from the vasa, piwi, and PL10 expressing mesodermal posterior growth zone (MPGZ at the end of larval development, suggesting a post-embryonic formation from stem cells. Methods In order to verify this hypothesis, embryos and larvae were pulse labeled with the proliferation marker 5-ethynyl-2'-deoxyuridine (EdU at different stages of development. Subsequently, the PGCs were visualized in 7-day-old young worms using antibodies against the Vasa protein. Results Surprisingly, the primordial germ cells of Platynereis incorporate EdU only shortly before gastrulation (6-8 hours post fertilization (hpf, which coincides with the emergence of four small blastomeres from the mesoblast lineage. We conclude that these so-called 'secondary mesoblast cells' constitute the definitive PGCs in Platynereis. In contrast, the cells of the MPGZ incorporate EdU only from the pre-trochophore stage onward (14 hpf. Conclusion While PGCs and the cells of the MPGZ in Platynereis are indistinguishable in morphology and both express the germline markers vasa, nanos, and piwi, a distinct cluster of PGCs is detectable anterior of the MPGZ following EdU pulse-labeling. Indeed the PGCs form independently from the stem cells of the MPGZ prior to gastrulation. Our data suggest an early PGC formation in the polychaete by preformation rather than by epigenesis.

  20. Trace metals partitioning among different sedimentary mineral phases and the deposit-feeding polychaete Armandia brevis

    Energy Technology Data Exchange (ETDEWEB)

    Díaz-de-Alba, Margarita [Department of Analytical Chemistry, Institute of Biomolecules (INBIO), Faculty of Sciences, CEI-MAR, University of Cadiz, Campus Rio S. Pedro, E-11510, Puerto Real, Cadiz (Spain); Huerta-Diaz, Miguel Angel, E-mail: huertam@uabc.edu.mx [Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Campus Ensenada, Km. 103 Carr. Tijuana-Ensenada, Ensenada 22800, Baja California (Mexico); Delgadillo-Hinojosa, Francisco [Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Campus Ensenada, Km. 103 Carr. Tijuana-Ensenada, Ensenada 22800, Baja California (Mexico); Hare, Landis [Centre Eau Terre Environnement, 490, rue de la Couronne, Québec, Québec G1K 9A9 (Canada); Galindo-Riaño, M. Dolores [Department of Analytical Chemistry, Institute of Biomolecules (INBIO), Faculty of Sciences, CEI-MAR, University of Cadiz, Campus Rio S. Pedro, E-11510, Puerto Real, Cadiz (Spain); Siqueiros-Valencia, Arturo [Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Campus Ensenada, Km. 103 Carr. Tijuana-Ensenada, Ensenada 22800, Baja California (Mexico)

    2016-02-01

    Trace metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) were determined in two operationally defined fractions (HCl and pyrite) in sediments from Ensenada and El Sauzal harbors (Mexico). The HCl fraction had significantly higher metal concentrations relative to the pyrite fraction in both harbors, underlining the weak tendency of most trace metals to associate with pyrite. Exceptionally, Cu was highly pyritized, with degrees of trace metal pyritization (DTMP) > 80% in both harbors. Dissolved Fe flux measurements combined with solid phase Fe sulfide data indicated that 98 mt of Fe are precipitated as iron sulfides every year in Ensenada Harbor. These Fe sulfides (and associated trace metals) will remain preserved in the sediments, unless they are perturbed by dredging or sediment resuspension. Calculations indicate that dredging activities could export to the open ocean 0.20 ± 0.13 to (0.30 ± 0.56) × 10{sup 3} mt of Cd and Cu, respectively, creating a potential threat to marine benthic organisms. Degrees of pyritization (DOP) values in Ensenada and El Sauzal harbors were relatively low (< 25%) while degrees of sulfidization (DOS) were high (~ 50%) because of the contribution of acid volatile sulfide. DOP values correlated with DTMP values (p ≤ 0.001), indicating that metals are gradually incorporated into pyrite as this mineral is formed. Significant correlations were also found between DTMP values and − log(K{sub sp(MeS)}/K{sub sp(pyr)}) for both harbors, indicating that incorporation of trace metals into the pyrite phase is a function of the solubility product of the corresponding metal sulfide. The order in which elements were pyritized in both harbors was Zn ≈ Mn < Fe < Cd ≈ Pb < Ni ≈ Co < < Cu. Lastly, a strong correlation (r{sup 2} = 0.87, p < 0.01) was found between average reactive trace metal concentrations and metal concentrations measured in Armandia brevis (a deposit-feeding Opheliid polychaete), suggesting that these labile sedimentary metals are

  1. Trace metals partitioning among different sedimentary mineral phases and the deposit-feeding polychaete Armandia brevis

    International Nuclear Information System (INIS)

    Díaz-de-Alba, Margarita; Huerta-Diaz, Miguel Angel; Delgadillo-Hinojosa, Francisco; Hare, Landis; Galindo-Riaño, M. Dolores; Siqueiros-Valencia, Arturo

    2016-01-01

    Trace metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) were determined in two operationally defined fractions (HCl and pyrite) in sediments from Ensenada and El Sauzal harbors (Mexico). The HCl fraction had significantly higher metal concentrations relative to the pyrite fraction in both harbors, underlining the weak tendency of most trace metals to associate with pyrite. Exceptionally, Cu was highly pyritized, with degrees of trace metal pyritization (DTMP) > 80% in both harbors. Dissolved Fe flux measurements combined with solid phase Fe sulfide data indicated that 98 mt of Fe are precipitated as iron sulfides every year in Ensenada Harbor. These Fe sulfides (and associated trace metals) will remain preserved in the sediments, unless they are perturbed by dredging or sediment resuspension. Calculations indicate that dredging activities could export to the open ocean 0.20 ± 0.13 to (0.30 ± 0.56) × 10"3 mt of Cd and Cu, respectively, creating a potential threat to marine benthic organisms. Degrees of pyritization (DOP) values in Ensenada and El Sauzal harbors were relatively low (< 25%) while degrees of sulfidization (DOS) were high (~ 50%) because of the contribution of acid volatile sulfide. DOP values correlated with DTMP values (p ≤ 0.001), indicating that metals are gradually incorporated into pyrite as this mineral is formed. Significant correlations were also found between DTMP values and − log(K_s_p_(_M_e_S_)/K_s_p_(_p_y_r_)) for both harbors, indicating that incorporation of trace metals into the pyrite phase is a function of the solubility product of the corresponding metal sulfide. The order in which elements were pyritized in both harbors was Zn ≈ Mn < Fe < Cd ≈ Pb < Ni ≈ Co < < Cu. Lastly, a strong correlation (r"2 = 0.87, p < 0.01) was found between average reactive trace metal concentrations and metal concentrations measured in Armandia brevis (a deposit-feeding Opheliid polychaete), suggesting that these labile sedimentary metals are

  2. The Response of Heterotrophic Prokaryote and Viral Communities to Labile Organic Carbon Inputs Is Controlled by the Predator Food Chain Structure.

    Science.gov (United States)

    Sandaa, Ruth-Anne; Pree, Bernadette; Larsen, Aud; Våge, Selina; Töpper, Birte; Töpper, Joachim P; Thyrhaug, Runar; Thingstad, Tron Frede

    2017-08-23

    Factors controlling the community composition of marine heterotrophic prokaryotes include organic-C, mineral nutrients, predation, and viral lysis. Two mesocosm experiments, performed at an Arctic location and bottom-up manipulated with organic-C, had very different results in community composition for both prokaryotes and viruses. Previously, we showed how a simple mathematical model could reproduce food web level dynamics observed in these mesocosms, demonstrating strong top-down control through the predator chain from copepods via ciliates and heterotrophic nanoflagellates. Here, we use a steady-state analysis to connect ciliate biomass to bacterial carbon demand. This gives a coupling of top-down and bottom-up factors whereby low initial densities of ciliates are associated with mineral nutrient-limited heterotrophic prokaryotes that do not respond to external supply of labile organic-C. In contrast, high initial densities of ciliates give carbon-limited growth and high responsiveness to organic-C. The differences observed in ciliate abundance, and in prokaryote abundance and community composition in the two experiments were in accordance with these predictions. Responsiveness in the viral community followed a pattern similar to that of prokaryotes. Our study provides a unique link between the structure of the predator chain in the microbial food web and viral abundance and diversity.

  3. Enhanced accumulation of starch and total carbohydrates in alginate-immobilized Chlorella spp. induced by Azospirillum brasilense: II. Heterotrophic conditions.

    Science.gov (United States)

    Choix, Francisco J; de-Bashan, Luz E; Bashan, Yoav

    2012-10-10

    The effect of the bacterium Azospirillum brasilense jointly immobilized with Chlorella vulgaris or C. sorokiniana in alginate beads on total carbohydrates and starch was studied under dark and heterotrophic conditions for 144 h in synthetic growth medium supplemented with either d-glucose or Na-acetate as carbon sources. In all treatments, enhanced total carbohydrates and starch content per culture and per cell was obtained after 24h; only jointly immobilized C. vulgaris growing on d-glucose significantly increased total carbohydrates and starch content after 96 h. Enhanced accumulation of carbohydrate and starch under jointly immobilized conditions was variable with time of sampling and substrate used. Similar results occurred when the microalgae was immobilized alone. In both microalgae growing on either carbon sources, the bacterium promoted accumulation of carbohydrates and starch; when the microalgae were immobilized alone, they used the carbon sources for cell multiplication. In jointly immobilized conditions with Chlorella spp., affinity to carbon source and volumetric productivity and yield were higher than when Chlorella spp. were immobilized alone; however, the growth rate was higher in microalgae immobilized alone. This study demonstrates that under heterotrophic conditions, A. brasilense promotes the accumulation of carbohydrates in two strains Chlorella spp. under certain time-substrate combinations, producing mainly starch. As such, this bacterium is a biological factor that can change the composition of compounds in microalgae in dark, heterotrophic conditions. Copyright © 2012. Published by Elsevier Inc.

  4. The effects of wastewater effluent and river discharge on benthic heterotrophic production, organic biomass and respiration in marine coastal sediments

    International Nuclear Information System (INIS)

    Burd, B.; Macdonald, T.; Bertold, S.

    2013-01-01

    Highlights: • High river particulate flux results in low sediment P/B due to large burrowers. • Sewage deposition results in high P/B from biomass depletion and bacterial increase. • Heterotrophic production was 56% of oxidized OC flux with 35% growth efficiency. • Production was correlated with organic/inorganic flux – biomass was not. • δ 15 N patterns illustrate feeding strategies of key taxa near the outfall. -- Abstract: We examine effects of high river particulate flux and municipal wastewater effluent on heterotrophic organic carbon cycling in coastal subtidal sediments. Heterotrophic production was a predictable (r 2 = 0.95) proportion (56%) of oxidized OC flux and strongly correlated with organic/inorganic flux. Consistent growth efficiencies (36%) occurred at all stations. Organic biomass was correlated with total, OC and buried OC fluxes, but not oxidized OC flux. Near the river, production was modest and biomass high, resulting in low P/B. Outfall deposition resulted in depleted biomass and high bacterial production, resulting in the highest P/B. These patterns explain why this region is production “saturated”. The δ 15 N in outfall effluent, sediments and dominant taxa provided insight into where, and which types of organisms feed directly on fresh outfall particulates, on older, refractory material buried in sediments, or utilize chemosynthetic symbiotic bacteria. Results are discussed in the context of declining bottom oxygen conditions along the coast

  5. Can we distinguish autotrophic respiration from heterotrophic respiration in a field site using high temporal resolution CO2 flux measurements?

    Science.gov (United States)

    Biro, Beatrice; Berger, Sina; Praetzel, Leandra; Blodau, Christian

    2016-04-01

    The processes behind C-cycling in peatlands are important to understand for assessing the vulnerability of peatlands as carbon sinks under changing climate conditions. Especially boreal peatlands are likely to underlie strong alterations in the future. It is expected that C-pools that are directly influenced by vegetation and water table fluctuations can be easily destabilized. The CO2 efflux through respiration underlies autotrophic and heterotrophic processes that show different feedbacks on changing environmental conditions. In order to understand the respiration fluxes better for more accurate modelling and prognoses, the determination of the relative importance of different respiration sources is necessary. Earlier studies used e.g. exfoliation experiments, incubation experiments or modelling approaches to estimate the different respiration sources for the total ecosystem respiration (Reco). To further the understanding in this topic, I want to distinguish autotrophic and heterotrophic respiration using high temporal resolution measurements. The study site was selected along a hydrological gradient in a peatland in southern Ontario (Canada) and measurements were conducted from May to September 2015 once per month. Environmental controls (water table, soil temperature and soil moisture) that effect the respiration sources were recorded. In my study I used a Li-COR 6400XT and a Los Gatos greenhouse gas analyzer (GGA). Reco was determined by chamber flux measurements with the GGA, while simultaneously CO2 respiration measurements on different vegetation compartments like roots, leaves and mosses were conducted using the Li-COR 6400XT. The difference between Reco and autotrophic respiration equals heterotrophic respiration. After the measurements, the vegetation plots were harvested and separated for all compartments (leaves, roots, mosses, soil organic matter), dried and weighed. The weighted respiration rates from all vegetation compartments sum up to

  6. The Ecology, Life History, and Phylogeny of the Marine Thecate Heterotrophic Dinoflagellates Protoperidinium and Diplopsalidaceae (Dinophyceae)

    Science.gov (United States)

    2006-09-01

    specimens, appeared to be identical to Actinophrys sol and other distinct protist species (as discussed in Coats 2002). Being unaware of the...hypothesizes that photosynthetic eukaryotes evolved through a series of symbiotic relationships between heterotrophic protists and autotrophic prokaryotes...species or genus level. Athecate dinoflagellates were not well preserved by formalin-fixation, and thus were not counted. Metazoans and protists

  7. Survival of heterotrophic bacteria in water environment under substrate deficiency

    International Nuclear Information System (INIS)

    Toth, D.

    1989-01-01

    The relationship between metabolic changes and survival of bacteria in the water environment under substrate deficiency was studied. The main factors supporting cell survival were cryptic growth, utilization of endogenous reserve substances and reorganization of metabolic activities. Based on the utilization of cell-free extract or lysates from dead bacteria, an Enterobacter aerogenes cell suspension yielded 50% more colonies. Metabolic processes of starved heterotrophic bacteria changed markedly and became stabilized at a lower level depending on species involved. The rate of utilization of endogenous reserve substances as indicated by endogenous respiration was related to the rate of cell mortality. Of the test bacteria, Pseudomonas fluorescens showed the lowest rates of endogenous respiration and mortality while in Enterobacter aerogenes these two rates were the highest. (author). 3 figs., 2 tabs.., 16 refs

  8. Stress management skills in the subsurface: H2 stress on thermophilic heterotrophs and methanogens

    Science.gov (United States)

    Topcuoglu, B. D.; Holden, J. F.

    2017-12-01

    Marine hyperthermophilic heterotrophs and methanogens belonging to the Thermococcales and Methanococcales are often found in subsurface environments such as coal and shale beds, marine sediments, and oil reservoirs where they encounter H2 stress conditions. It is important to study the H2 stress survival strategies of these organisms and their cooperation with one another for survival to better understand their biogeochemical impact in hot subsurface environments. In this study, we have shown that H2 inhibition changed the growth kinetics and the transcriptome of Thermococcus paralvinellae. We observed a significant decrease in batch phase growth rates and cell concentrations with high H2 background. Produced metabolite production measurements, RNA-seq analyses of differentially expressed genes and in silico experiments we performed with the T. paralvinellae metabolic model showed that T. paralvinellae produces formate by a formate hydrogenlyase to survive H2 inhibition. We have also shown that H2 limitation caused a significant decrease in batch phase growth rates and methane production rates of the methanogen, Methanocaldococcus jannaschii. H2 stress of both organisms can be ameliorated by syntrophic growth. H2 syntrophy was demonstrated in microcosm incubations for a natural assemblage of Thermococcus and hyperthermophilic methanogens present in hydrothermal fluid samples. This project aims to describe how a hyperthermophilic heterotroph and a hyperthermophilic methanogen eliminate H2 stress and explore cooperation among thermophiles in the hot subsurface.

  9. Antimicrobial activity of heterotrophic bacterial communities from the marine sponge Erylus discophorus (Astrophorida, Geodiidae.

    Directory of Open Access Journals (Sweden)

    Ana Patrícia Graça

    Full Text Available Heterotrophic bacteria associated with two specimens of the marine sponge Erylus discophorus were screened for their capacity to produce bioactive compounds against a panel of human pathogens (Staphylococcus aureus wild type and methicillin-resistant S. aureus (MRSA, Bacillus subtilis, Pseudomonas aeruginosa, Acinetobacter baumanii, Candida albicans and Aspergillus fumigatus, fish pathogen (Aliivibrio fischeri and environmentally relevant bacteria (Vibrio harveyi. The sponges were collected in Berlengas Islands, Portugal. Of the 212 isolated heterotrophic bacteria belonging to Alpha- and Gammaproteobacteria, Actinobacteria and Firmicutes, 31% produced antimicrobial metabolites. Bioactivity was found against both Gram positive and Gram negative and clinically and environmentally relevant target microorganisms. Bioactivity was found mainly against B. subtilis and some bioactivity against S. aureus MRSA, V. harveyi and A. fisheri. No antifungal activity was detected. The three most bioactive genera were Pseudovibrio (47.0%, Vibrio (22.7% and Bacillus (7.6%. Other less bioactive genera were Labrenzia, Acinetobacter, Microbulbifer, Pseudomonas, Gordonia, Microbacterium, Micrococcus and Mycobacterium, Paenibacillus and Staphylococcus. The search of polyketide I synthases (PKS-I and nonribosomal peptide synthetases (NRPSs genes in 59 of the bioactive bacteria suggested the presence of PKS-I in 12 strains, NRPS in 3 strains and both genes in 3 strains. Our results show the potential of the bacterial community associated with Erylus discophorus sponges as producers of bioactive compounds.

  10. Effects of acute irradiation on reproductive success of the polychaete worm, Neanthes arenaceodentata

    International Nuclear Information System (INIS)

    Harrison, F.L.; Anderson, S.L.

    1994-01-01

    Effects of acute irradiation on the reproductive success of a relatively low-fecundity species were investigated by exposing pairs of female and male polychaete worms (Neanthes arenaceodentata) to either no radiation (controls) or 0.5, 1.0, 2.0, 5.0, 10 or 50 Gy of acute irradiation (5 Gy min -1 ) at the time when oocytes were visible in the female. The broods from the pairs were sacrificed before hatching occurred, and information was obtained on the number in the brood, the number of normal and abnormal embryos, and the number of embryos that were living, dying and dead. Developing gametes of N. arenaceodentata appeared to be sensitive to acute irradiation. There was a significant reduction in the percentage of live embryos in the broods from pairs receiving doses as low as 0.5 Gy, which is lower than the lowest dose at which effects in invertebrates have been reported previously. This was most likely due to the induction of lethal mutations in the developing gametes, which affected the survival of embryos in early stages of life. Except for those pairs receiving 10 or 50 Gy, there was no evidence of decreased fertility or fecundity or of reduced fertilization success; the number of embryos in the broods from only these irradiated groups was significantly different from the controls. 32 refs., 3 figs., 2 tabs

  11. Growth of legionella and other heterotrophic bacteria in a circulating cooling water system exposed to ultraviolet irradiation

    International Nuclear Information System (INIS)

    Kusnetsov, J.M.; Miettinen, I.T.; Martikainen, P.J.; Keskitalo, P.J.; Ahonen, H.E.; Tulkki, A.I.

    1994-01-01

    The effect of ultraviolet irradiation on the growth and occurrence of legionella and other heterotrophic bacteria in a circulating cooling water system was studied. Water of the reservoir was circulated once in 28 h through a side-stream open channel u.v. radiator consisting of two lamps. Viable counts of legionellas and heterotrophic bacteria in water immediately after the u.v. treatment were 0-12 and 0.7-1.2% of those in the reservoir, respectively. U.v. irradiation increased the concentration of easily assimilable organic carbon. In the u.v. irradiated water samples incubated in the laboratory the viable counts of heterotropic bacteria reached the counts in reservoir water within 5 d. The increase in viable counts was mainly due to reactivation of bacterial cells damaged by u.v. light, not because of bacterial multiplication. Despite u.v. irradiation the bacterial numbers in the reservoir water, including legionellas, did not decrease during the experimental period of 33 d. The main growth of bacteria in the reservoir occurred in biofilm and sediment, which were never exposed to u.v. irradiation. (Author)

  12. The search for a filter-feeding alternative for integrated shrimp aquacultures– a preliminary study with the polychaete Sabella spallanzanii for water quality improvement

    Directory of Open Access Journals (Sweden)

    Luana Granada

    2014-06-01

    Relatively to bacteriological analysis, the density of heterotrophic bacteria at 37ºC decreased substantially (Fig. 1a. The abundance of heterotrophic bacteria at 22ºC increased from T0 to T3 (Fig. 1b. This increasing density pattern of heterotrophic bacteria at 22ºC is in accordance with Stabili et al. (2010. The author stated that could be related with the effect of temperature, assessed by Pomeroy & Wiebe (2001. However, in this study no large temperature changes occur. Thus, more intensive bacteriological analyses should be done before performing any assumptions. Regarding culturable presumptive vibrios, the abundance decreased from T0 to T3 at 22 and 35ºC (Fig. 2. Regarding to E.coli, it was possible to observe a density decrease of 90% at the end of the experiment (Fig. 3. According with the decree-law n.º 236/98 of August 1st (N.º 176 – 1998, the maximum value allowable for faecal coliforms is 2000 per 100 mL, and the maximum value recommended is 100 per 100 mL. The results for E. coli stated previously are in accordance with the decree-law requirements. The use of S. spallanzanii as bioremediator of microbial pollution revealed to be efficient in a more complex culture system. The integration of this species in the culture system plays an important role since it is able to filter, accumulate and remove several bacterial groups from the water, including human potential pathogens, and thus, reduces susceptibility to disease outbreaks.

  13. Development of a novel artificial medium based on utilization of algal photosynthetic metabolites by symbiotic heterotrophs.

    Science.gov (United States)

    Watanabe, K; Imase, M; Aoyagi, H; Ohmura, N; Saiki, H; Tanaka, H

    2008-09-01

    (i) Quantitative and qualitative analyses of photosynthetic metabolites of Chlorella sorokiniana and elucidation of the mechanism of their utilization by algal symbionts. (ii) Development of artificial medium that imitates photoautotroph-heterotroph interaction and investigation of its suitability for isolation of novel microbes from the environment. Various components, including free dissolved carbohydrates, nitrogenous compounds and vitamin, were detected and together contributed 11.1% (as carbon content) of the total photosynthetic metabolites in the medium. Utilization of these photosynthetic metabolites in algal culture broth by algal symbionts was studied. Many symbionts showed specific utilization patterns. A novel artificial extracellular released organic carbon medium, which imitated the nutritional conditions surrounding algae, was developed based on the pattern of utilization of the algal metabolites by the symbiotic heterotrophs. About 42.9% of the isolates were closely related to photoautotrophic-dependent and oligotrophic bacteria. With the novel artificial medium, it was possible to selectively isolate some bacterial strains. Synthetic bacterial growth medium is an important and basic tool for bacterial isolation from environmental samples. The current study shows that preferential separation of typical bacterial subset can be achieved by using artificial medium that mimics photosynthetic metabolites.

  14. DNA methylation and temperature stress in an Antarctic polychaete, Spiophanes tcherniai.

    Science.gov (United States)

    Marsh, Adam G; Pasqualone, Annamarie A

    2014-01-01

    Epigenetic modifications of DNA and histones are a primary mechanism by which gene expression activities may be modified in response to environmental stimuli. Here we characterize patterns of methyl-cytosine composition in the marine polychaete Spiophanes tcherniai from McMurdo Sound, Antarctica. We cultured adult worms at two temperatures, -1.5°C (ambient control) and +4°C (warm treatment), for 4 weeks. We observed a rapid capacity for S. tcherniai organismal respiration rates and underlying catalytic rates of citrate synthase at +4°C to return to control levels in less than 4 weeks. We profiled changes in the methylation states of CpG sites in these treatments using an NGS strategy to computationally reconstruct and quantify methylation status across the genome. In our analysis we recovered 120,000 CpG sites in assembled contigs from both treatments. Of those, we were able to align 28,000 CpG sites in common between the two sample groups. In comparing these aligned sites between treatments, only 3000 (11%) evidenced a change in methylation state, but over 85% of changes involved a gain of a 5-methyl group on a CpG site (net increase in methyation). The ability to score CpG sites as partially methylated among gDNA copies in a sample opens up a new avenue for assessing DNA methylation responses to changing environments. By quantitatively distinguishing a "mixed" population of copies of one CpG site, we can begin to identify dynamic, non-binary, continuous-response reactions in DNA methylation intensity or density that previously may have been overlooked as noise.

  15. DNA Methylation and Temperature Stress in an Antarctic Polychaete, Spiophanes tcherniai

    Directory of Open Access Journals (Sweden)

    Adam G. Marsh

    2014-05-01

    Full Text Available Epigenetic modifications of DNA and histones are a primary mechanism by which gene expression activities may be modified in response to environmental stimuli. Here we characterize patterns of methyl-cytosine composition in the marine polychaete emph{Spiophanes tcherniai} from McMurdo Sound, Antarctica. We cultured adult worms at two temperatures, -1.5 C (ambient control and +4 C (warm treatment, for four weeks. We observed a rapid capacity for emph{S. tcherniai} organismal respiration rates and underlying catalytic rates of citrate synthase to acclimate at +4 C and return to control levels. We profiled changes in the methylation states of CpG sites in these treatments using an NGS strategy to computationally reconstruct and quantify methylation status across the genome. In our analysis we recovered 120,000 CpG sites in assembled contigs from both treatments. Of those, we were able to align 28,000 CpG sites in common between the two sample groups. In comparing these aligned sites between treatments, only 3,000 (11% evidenced a change in methylation state, but over 85% of changes involved a gain of a 5-methyl group on a CpG site (net increase in methyation. The ability to score CpG sites as partially methylated among gDNA copies in a sample opens up a new avenue for assessing DNA methylation responses to changing environments. By quantitatively distinguishing a ``mixed'' population of copies of one CpG site, we can begin to identify dynamic, non-binary, continuous-response reactions in DNA methylation intensity or density that previously may have been overlooked as noise.

  16. Responses of heterotrophic bacteria abundance and activity to Asian dust enrichment in the low nutrients and low chlorophyll (LNLC) region of the Northwestern Pacific Ocean

    Science.gov (United States)

    Shi, Dongwan; Li, Kuiran; Tian, Yanzhao; Zhang, Xiaohao; Bai, Jie

    2017-05-01

    Bacteria, as an essential part of microbial food web, play a significant role in the marine ecosystem. Dust deposits into the surface ocean carrying with vital nutrient such as Inorganic nitrogen and phosphorus etc., which has an important influence on the life activities of heterotrophic bacteria. The microcosm experiments with Asian dust deposition was carried out on board in the station K3 (26.18°N, 136.73°E) in April 2015, aiming to estimate the impact of dust deposition on the oligotrophic Northwestern pacific Sea, the main goal of the present paper was to assess how dust deposition events affect the abundance and activity of heterotrophic bacteria in low nutrient and low chlorophyll (LNLC) sea area. Station K3 located in the central northwestern Pacific Ocean, which has the characteristic of low nutrient and low chlorophyll. The study shows that there was an N-P co-limitation in station K3, and the deposition of Asian dust can increase the abundance, and promote the activity of heterotrophic bacteria in the station K3.

  17. Heterotrophic soil respiration in forestry-drained peatlands

    International Nuclear Information System (INIS)

    Minkkinen, K.; Shurpali, N. J.; Alm, J.; Penttilae, T.

    2007-01-01

    Heterotrophic soil respiration (CO 2 efflux from the decomposition of peat and root litter) in three forestry-drained peatlands with different site types and with a large climatic gradient from the hemi-boreal (central Estonia) to south (southern Finland) and north boreal (northern Finland) conditions was studied. Instantaneous fluxes varied between 0 and 1.3 g CO 2 -C m -2 h -1 , and annual fluxes between 248 and 515 g CO 2 -C m -2 a -1 . Variation in the annual fluxes among site types was studied only in the south-boreal site where we found a clear increase from nutrient-poor to nutrient-rich site types. More than half of the within-site variation was temporal and explained by soil surface (-5 cm) temperature (T5). The response of soil respiration to T5 varied between the sites; the most northerly site had the highest response to T5 and the most southerly the lowest. This trend further resulted in increased annual fluxes towards north. This unexpected result is hypothesised to be related to differences in site factors like substrate quality, nutrient status and hydrology but also to temperature acclimation, i.e., adaptation of decomposer populations to different climates. (orig.)

  18. Comparison of the effect of salinity on the D/H ratio of fatty acids of heterotrophic and photoautotrophic microorganisms

    NARCIS (Netherlands)

    Heinzelmann, S.M.; Chivall, David; M'Boule, D.; Sinke-Schoen, Daniëlle; Villanueva, Laura; Sinninghe Damste, J.S.; Schouten, Stefan; Van der Meer, Marcel T J

    2015-01-01

    The core metabolism of microorganisms has a major influence on the hydrogen isotopic composition of their fatty acids. Heterotrophic microorganisms produce fatty acids with a deuterium to hydrogen (D/H) ratio either slightly depleted or enriched in D compared to the growth water, while photo- and

  19. Macroalgal blooms favor heterotrophic diazotrophic bacteria in nitrogen-rich and phosphorus-limited coastal surface waters in the Yellow Sea

    Science.gov (United States)

    Zhang, Xiaoli; Song, Yanjing; Liu, Dongyan; Keesing, John K.; Gong, Jun

    2015-09-01

    Macroalgal blooms may lead to dramatic changes in physicochemical variables and biogeochemical cycling in affected waters. However, little is known about the effects of macroalgal blooms on marine bacteria, especially those functioning in nutrient cycles. We measured environmental factors and investigated bacterial diazotrophs in two niches, surface waters that were covered (CC) and non-covered (CF) with massive macroalgal canopies of Ulva prolifera, in the Yellow Sea in the summer of 2011 using real-time PCR and clone library analysis of nifH genes. We found that heterotrophic diazotrophs (Gammaproteobacteria) dominated the communities and were mostly represented by Vibrio-related phylotypes in both CC and CF. Desulfovibrio-related phylotypes were only detected in CC. There were significant differences in community composition in these two environments (p diazotrophic abundance and community composition and that vibrios and Desulfovibrio-related heterotrophic diazotrophs adapt well to the (N-rich but P-limited) environment during blooming. Potential ecological and microbiological mechanisms behind this scenario are discussed.

  20. The Effect of Variation in Developmental Mode on the Population Dynamics of a Spionid Polychaete (Pygospio elegans) in a Heterogeneous Environment

    DEFF Research Database (Denmark)

    Thonig, Anne

    by the short life span of P. elegans and sweepstakes reproductive success. Additionally, stochastic events, such as rain storms, can lead to abrupt drops in salinity which can be detrimental for P. elegans and hence introduce further changes in population structure. Seasonal dynamics, including sexual...... of poecilogonous species that show a polymorphism in developmental mode might be more useful than are comparisons between species, since no confounding effects due to speciation arise. In this study, I documented the population ecology and genetics of the poecilogonous polychaete P. elegans and investigated...... the impact of abiotic and biotic variables on population dynamics. Four focal populations from the Isefjord-RoskildeFjord estuary complex, Denmark were sampled over one year. I observed highly dynamic population structure in both size cohort data and population genetic data that is possibly explained...

  1. Deep subsurface life from North Pond: enrichment, isolation, characterization and genomes of heterotrophic bacteria

    Directory of Open Access Journals (Sweden)

    Joseph A. Russell

    2016-05-01

    Full Text Available Studies of subsurface microorganisms have yielded few environmentally relevant isolates for laboratory studies. In order to address this lack of cultivated microorganisms, we initiated several enrichments on sediment and underlying basalt samples from North Pond, a sediment basin ringed by basalt outcrops underlying an oligotrophic water-column west of the Mid-Atlantic Ridge at 22°N. In contrast to anoxic enrichments, growth was observed in aerobic, heterotrophic enrichments from sediment of IODP site U1382B at 4 and 68 meters below seafloor (mbsf. These sediment depths, respectively, correspond to the fringes of oxygen penetration from overlying seawater in the top of the sediment column and upward migration of oxygen from oxic seawater from the basalt aquifer below the sediment. Here we report the enrichment, isolation, and initial characterizations of three isolated aerobic heterotrophs from North Pond sediments; an Arthrobacter species from 4 mbsf, and Paracoccus and Pseudomonas species from 68 mbsf. These cultivated bacteria are represented in the amplicon 16S rRNA gene libraries created from whole sediments, albeit at low (up to 2% relative abundance. We provide genomic evidence from our isolates demonstrating that the Arthrobacter and Pseudomonas isolates have the potential to respire nitrate and oxygen, though dissimilatory nitrate reduction could not be confirmed in laboratory cultures. The cultures from this study represent members of environmentally significant phyla, and allow for further studies into geochemical factors impacting life in the deep subsurface.

  2. Deep Subsurface Life from North Pond: Enrichment, Isolation, Characterization and Genomes of Heterotrophic Bacteria.

    Science.gov (United States)

    Russell, Joseph A; León-Zayas, Rosa; Wrighton, Kelly; Biddle, Jennifer F

    2016-01-01

    Studies of subsurface microorganisms have yielded few environmentally relevant isolates for laboratory studies. In order to address this lack of cultivated microorganisms, we initiated several enrichments on sediment and underlying basalt samples from North Pond, a sediment basin ringed by basalt outcrops underlying an oligotrophic water-column west of the Mid-Atlantic Ridge at 22°N. In contrast to anoxic enrichments, growth was observed in aerobic, heterotrophic enrichments from sediment of IODP Hole U1382B at 4 and 68 m below seafloor (mbsf). These sediment depths, respectively, correspond to the fringes of oxygen penetration from overlying seawater in the top of the sediment column and upward migration of oxygen from oxic seawater from the basalt aquifer below the sediment. Here we report the enrichment, isolation, initial characterization and genomes of three isolated aerobic heterotrophs from North Pond sediments; an Arthrobacter species from 4 mbsf, and Paracoccus and Pseudomonas species from 68 mbsf. These cultivated bacteria are represented in the amplicon 16S rRNA gene libraries created from whole sediments, albeit at low (up to 2%) relative abundance. We provide genomic evidence from our isolates demonstrating that the Arthrobacter and Pseudomonas isolates have the potential to respire nitrate and oxygen, though dissimilatory nitrate reduction could not be confirmed in laboratory cultures. The cultures from this study represent members of abundant phyla, as determined by amplicon sequencing of environmental DNA extracts, and allow for further studies into geochemical factors impacting life in the deep subsurface.

  3. Metal accumulation in the polychaete Hediste japonica with emphasis on interaction between heavy metals and petroleum hydrocarbons

    International Nuclear Information System (INIS)

    Sun Fuhong; Zhou Qixing

    2007-01-01

    The accumulation of cadmium (Cd) and copper (Cu) in the polychaete Hediste japonica exposed to the mixture of Cd (or Cu) and petroleum hydrocarbons (PHCs) was investigated and compared with that exposed to single Cd (or Cu). The increased bioavailability of Cd or Cu with exposure concentrations resulted in an increase in the accumulation and net accumulation rate of Cd or Cu during single metal exposure. The net accumulation rate of Cd increased, but the net accumulation rate of Cu decreased with exposure time during single metal exposure, suggesting that H. japonica could actively regulate Cu burden in their body by inhibition of absolute uptake or promotion of excretion. The interactions between Cd (or Cu) and PHCs had complicated influences on the net accumulation rate of Cd and Cu in H. japonica under the condition of the binary mixture, which are dependent on their concentration combinations and exposure time. - The influences of petroleum hydrocarbons on Cd and Cu accumulation in H. japonica depend on their concentration combinations and exposure time

  4. Impacts of ocean acidification on sperm develop with exposure time for a polychaete with long lived sperm.

    Science.gov (United States)

    Campbell, Anna L; Ellis, Robert P; Urbina, Mauricio A; Mourabit, Sulayman; Galloway, Tamara S; Lewis, Ceri

    2017-08-01

    The majority of marine invertebrate species release eggs and sperm into seawater for external fertilisation. Seawater conditions are currently changing at an unprecedented rate as a consequence of ocean acidification (OA). Sperm are thought to be particularly vulnerable to these changes and may be exposed to external environmental conditions for variable periods of time between spawning and fertilisation. Here, we undertook a mechanistic investigation of sperm swimming performance in the coastal polychaete Arenicola marina during an extended exposure to OA conditions (pH NBS 7.77, 1000 μatm pCO 2 ). We found that key fitness-related aspects of sperm functioning declined faster under OA conditions i.e. impacts became apparent with exposure time. Sperm swimming speed (VCL), the number of motile sperm and sperm path linearity all dropped significantly after 4 h under OA conditions whilst remaining constant under ambient conditions at this time point. Our results highlight the importance of sperm exposure duration in ocean acidification experiments and may help towards explaining species specific differences in response. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. C isotope fractionation during heterotrophic activity driven carbonate precipitation

    Science.gov (United States)

    Balci, Nurgul; Demirel, Cansu

    2016-04-01

    Stable carbon isotopic fractionation during carbonate precipitation induced by environmentally enriched heterotrophic halophilic microorganims was experimentally investigated under various salinity (% 4.5, %8, %15) conditions at 30 °C. Halophilic heterotrophic microorganims were enriched from a hypersaline Lake Acigöl located in SW Turkey (Balci et al.,2015) and later used for the precipitation experiments (solid and liquid medium). The carbonate precipitates had relatively high δ13C values (-4.3 to -16.9 ‰) compared to the δ13C values of the organic compounds that ranged from -27.5 to -25.4 ‰. At salinity of 4.5 % δ13C values of carbonate ranged from -4.9 ‰ to -10.9 ‰ with a 13C-enrichment factor of +20 to +16 ‰ higher than the δ13C values of the associated DOC (-27.5) . At salinity 8 % δ13C values of carbonate ranged from -16.3 ‰ to -11.7 ‰ with a 13C-enrichment factor of+11.3 to+15.9 ‰ higher than the δ13C values of the associated DOC. The respected values for 15 % salinity ranged from -12.3 ‰ to -9.7 ‰ with a 13C-enrichment factor of +15.2 to+16.8 ‰ higher than the δ13C values of the associated DOC. The carbonate precipitates produced in the solid medium are more enriched in 13C relative to liquid culture experiments. These results suggest that the carbon in the solid was derived from both the bacterial oxidation of organic compounds in the medium and from the atmospheric CO2. A solid medium used in the experiments may have suppressed convective and advective mass transport favouring diffusion-controlled system. This determination suggests that the rate and equilibration of CO2 exchange with the atmosphere is the major control on C isotope composition of carbonate minerals precipitated in the experiments. Key words: Lake Acıgöl, halophilic bacteria, carbonate biomineralization, C isotopes References Nurgul Balci, Meryem Menekşe, Nevin Gül Karagüler, M. Şeref Sönmez,Patrick Meister 2015.Reproducing authigenic carbonate

  6. Genomic analysis reveals versatile heterotrophic capacity of a potentially symbiotic sulfur-oxidizing bacterium in sponge

    KAUST Repository

    Tian, Renmao

    2014-08-29

    Sulfur-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) play essential roles in marine sponges. However, the detailed characteristics and physiology of the bacteria are largely unknown. Here, we present and analyse the first genome of sponge-associated SOB using a recently developed metagenomic binning strategy. The loss of transposase and virulence-associated genes and the maintenance of the ancient polyphosphate glucokinase gene suggested a stabilized SOB genome that might have coevolved with the ancient host during establishment of their association. Exclusive distribution in sponge, bacterial detoxification for the host (sulfide oxidation) and the enrichment for symbiotic characteristics (genes-encoding ankyrin) in the SOB genome supported the bacterial role as an intercellular symbiont. Despite possessing complete autotrophic sulfur oxidation pathways, the bacterium developed a much more versatile capacity for carbohydrate uptake and metabolism, in comparison with its closest relatives (Thioalkalivibrio) and to other representative autotrophs from the same order (Chromatiales). The ability to perform both autotrophic and heterotrophic metabolism likely results from the unstable supply of reduced sulfur in the sponge and is considered critical for the sponge-SOB consortium. Our study provides insights into SOB of sponge-specific clade with thioautotrophic and versatile heterotrophic metabolism relevant to its roles in the micro-environment of the sponge body. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Study of a combined heterotrophic and sulfur autotrophic denitrification technology for removal of nitrate in water

    International Nuclear Information System (INIS)

    Liu Huijuan; Jiang Wei; Wan Dongjin; Qu Jiuhui

    2009-01-01

    A combined two-step process of heterotrophic denitrification in a fluidized reactor and sulfur autotrophic denitrification processes (CHSAD) was developed for the removal of nitrate in drinking water. In this process, the advantage of high efficiency of heterotrophic denitrification with non-excessive methanol and the advantage of non-pollution of sulfur autotriphic denitrification were integrated in this CHSAD process. And, this CHSAD process had the capacity of pH balance and could control the concentration of SO 4 2- in effluent by adjusting the operation condition. When the influent nitrate was 30 mg NO 3 - -N/L, the reactor could be operated efficiently at the hydraulic retention time (HRT) ranging from 20 to 40 min with C:N ratio (mg CH 3 OH:mg NO 3 - -N) of 2.0 (methanol as carbon source). The nitrate removal was nearly 100% and there was no accumulated nitrite or residual methanol in the effluent. The effluent pH was about 7.5 and the sulfate concentration was lower than 130 mg/L. The maximum volume-loading rate of the reactor was 2.16 kg NO 3 - -N/(m 3 d). The biomass and scanning electron microscopy graphs of biofilm were also analyzed.

  8. Interactions between the mixotrophic dinoflagellate Takayama helix and common heterotrophic protists.

    Science.gov (United States)

    Ok, Jin Hee; Jeong, Hae Jin; Lim, An Suk; Lee, Kyung Ha

    2017-09-01

    The phototrophic dinoflagellate Takayama helix that is known to be harmful to abalone larvae has recently been revealed to be mixotrophic. Although mixotrophy elevates the growth rate of T. helix by 79%-185%, its absolute growth rate is still as low as 0.3d -1 . Thus, if the mortality rate of T. helix due to predation is high, this dinoflagellate may not easily prevail. To investigate potential effective protistan grazers on T. helix, feeding by diverse heterotrophic dinoflagellates such as engulfment-feeding Oxyrrhis marina, Gyrodinium dominans, Gyrodinium moestrupii, Polykrikos kofoidii, and Noctiluca scintillans, peduncle-feeding Aduncodinium glandula, Gyrodiniellum shiwhaense, Luciella masanensis, and Pfiesteria piscicida, pallium-feeding Oblea rotunda and Protoperidinium pellucidum, and the naked ciliates Pelagostrobilidium sp. (ca. 40μm in cell length) and Strombidinopsis sp. (ca. 150μm in cell length) on T. helix was explored. Among the tested heterotrophic protists, O. marina, G. dominans, G. moestrupii, A. glandula, L. masanensis, P. kofoidii, P. piscicida, and Strombidinopsis sp. were able to feed on T. helix. The growth rates of all these predators except Strombidinopsis sp. with T. helix prey were lower than those without the prey. The growth rate of Strombidinopsis sp. on T. helix was almost zero although the growth rate of Strombidinopsis sp. with T. helix prey was higher than those without the prey. Moreover, T. helix fed on O. marina and P. pellucidum and lysed the cells of P. kofoidii and G. shiwhaense. With increasing the concentrations of T. helix, the growth rates of O. marina and P. kofoidii decreased, but those of G. dominans and L. masanensis largely did not change. Therefore, reciprocal predation, lysis, no feeding, and the low ingestion rates of the common protists preying on T. helix may result in a low mortality rate due to predation, thereby compensating for this species' low growth rate. Copyright © 2017 Elsevier B.V. All rights

  9. Solazyme Integrated Biorefinery (SzIBR): Diesel Fuels from Heterotrophic Algae

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, David [Solazyme, Inc., South San Francisco, CA (United States)

    2014-12-23

    Under Department of Energy Award Number DE-EE0002877 (the “DOE Award”), Solazyme, Inc. (“Solazyme”) has built a demonstration scale “Solazyme Integrated Biorefinery (SzlBR).” The SzIBR was built to provide integrated scale-up of Solazyme’s novel heterotrophic algal oil biomanufacturing process, validate the projected commercial-scale economics of producing multiple algal oils, and to enable Solazyme to collect the data necessary to complete the design of its first commercial-scale facility. Solazyme’s technology enables it to convert a range of low-cost plant-based sugars into high-value oils. Solazyme’s renewable products replace or enhance oils derived from the world’s three existing sources—petroleum, plants, and animal fats. Solazyme tailors the composition of its oils to address specific customer requirements, offering superior performance characteristics and value. This report summarizes history and the results of the project.

  10. Biofouling likely serves as a major mode of dispersal for the polychaete tubeworm Hydroides elegans as inferred from microsatellite loci.

    Science.gov (United States)

    Pettengill, J B; Wendt, D E; Schug, M D; Hadfield, M G

    2007-01-01

    The polychaete tubeworm Hydroides elegans (Haswell) is a biofouling species with relatively limited larval dispersal. Four highly polymorphic microsatellite loci were used to make inferences about the migration and global population structure of 137 individuals from seven sub-populations located in the Atlantic, Pacific, and Indian Oceans and in the Mediterranean Sea. The results of the genetic analyses suggest minimal population sub-structure (F(st) = 0.09). Estimates of pairwise F(st) and migration rates using the coalescent-based method of MIGRATE suggest that there is little genetic differentiation between certain populations. Variation in relatedness among pairs of populations is consistent with a suite of local and global factors. The most likely explanation for close genetic relatedness among certain populations over such vast distances is the regular and consistent transport of adults and larvae on the hulls and in the ballast water of ships, respectively.

  11. Global net primary production and heterotrophic respiration for 1987

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, R.E. Jr.; Piper, S.C.; Nemani, R. [Univ. of Montana, Missoula, MT (United States)]|[Scripps Institute of Oceanography, La Jolla, CA (United States)] [and others

    1995-06-01

    An ecosystem process model, BIOME-BGC, was parameterized and used to simulate the actual net primary production and heterotrophic respiration using daily climatic data, land cover type, leaf area index gridded to 1{degree} latitude by 1{degree} longitude grid cells for the year 1987. Global net primary production was 52 Pg C. These estimates were validated directly by two different methods. First, the grid cells were aggregated and used as inputs to a 3D atmospheric transport model, to compare CO{sub 2} station data with predictions. We simulated the intra-annual variation of atmospheric CO{sub 2} well for the northern hemisphere, but not for the southern hemisphere. Second, we calculated the net {sup 13}C uptake of vegetation, which is a function of water use efficiency. The {sup 13}C/{sup 12}C ratios agreed with measured data, indicating a strong limitation of global primary processes by the hydrologic cycle, especially precipitation. These are different from other global carbon models as we can simulate the year-to-year variation of climate, including El Nino, on the global carbon cycle.

  12. Reducing Uncertainty in the Daycent Model of Heterotrophic Respiration with a More Mechanistic Representation of Microbial Processes.

    Science.gov (United States)

    Berardi, D.; Gomez-Casanovas, N.; Hudiburg, T. W.

    2017-12-01

    Improving the certainty of ecosystem models is essential to ensuring their legitimacy, value, and ability to inform management and policy decisions. With more than a century of research exploring the variables controlling soil respiration, a high level of uncertainty remains in the ability of ecosystem models to accurately estimate respiration with changing climatic conditions. Refining model estimates of soil carbon fluxes is a high priority for climate change scientists to determine whether soils will be carbon sources or sinks in the future. We found that DayCent underestimates heterotrophic respiration by several magnitudes for our temperate mixed conifer forest site. While traditional ecosystem models simulate decomposition through first order kinetics, recent research has found that including microbial mechanisms explains 20 percent more spatial heterogeneity. We manipulated the DayCent heterotrophic respiration model to include a more mechanistic representation of microbial dynamic and compared the new model with continuous and survey observations from our experimental forest site in the Northern Rockies ecoregion. We also calibrated the model's sensitivity to soil moisture and temperature to our experimental data. We expect to improve the accuracy of the model by 20-30 percent. By using a more representative and calibrated model of soil carbon dynamics, we can better predict feedbacks between climate and soil carbon pools.

  13. Development of a laboratory model of a phototroph-heterotroph mixed-species biofilm at the stone/air interface

    Directory of Open Access Journals (Sweden)

    Federica eVilla

    2015-11-01

    Full Text Available Recent scientific investigations have shed light on the ecological importance and physiological complexity of subaerial biofilms (SABs inhabiting lithic surfaces. In the field of sustainable cultural heritage (CH preservation, mechanistic approaches aimed at investigation of the spatiotemporal patterns of interactions between the biofilm, the stone, and the atmosphere are of outstanding importance. However, these interactions have proven difficult to explore with field experiments due to the inaccessibility of samples, the complexity of the ecosystem under investigation and the temporal resolution of the experiments.To overcome these limitations, we aimed at developing a unifying methodology to reproduce a fast-growing, phototroph-heterotroph mixed species biofilm at the stone/air interface. Our experiments underscore the ability of the dual-species SAB model to capture functional traits characteristic of biofilms inhabiting lithic substrate such as: i microcolonies of aggregated bacteria; ii network like structure following surface topography; iii cooperation between phototrophs and heterotrophs and cross feeding processes; iv ability to change the chemical parameters that characterize the microhabitats; v survival under desiccation and vi biocide tolerance. With its advantages in control, replication, range of different experimental scenarios and matches with the real ecosystem, the developed model system is a powerful tool to advance our mechanistic understanding of the stone-biofilm-atmosphere interplay in different environments.

  14. Characterization of novel Bacillus strain N31 from mariculture water capable of halophilic heterotrophic nitrification-aerobic denitrification.

    Science.gov (United States)

    Huang, Fei; Pan, Luqing; Lv, Na; Tang, Xianming

    2017-11-01

    The development of an intensive aquaculture industry has been accompanied by increasing environmental impacts, especially nitrogen pollution. In this study, a novel halophilic bacterium capable of heterotrophic nitrification and aerobic denitrification was isolated from mariculture water and identified as Bacillus litoralis N31. The efficiency of ammonium, nitrite and nitrate removal by N31 were 86.3%, 89.3% and 89.4%, respectively, after a 48-h cultivation in sole N-source medium with initial nitrogen approximately 20 mg/L. However, ammonium was removed preferentially, and no obvious nitrite accumulated during the simultaneous nitrification and denitrification process in mixed N-source media. The existence of hao, napA and nirS genes further proved the heterotrophic nitrification-aerobic denitrification capability of N31. The optimal conditions for ammonium removal were 30°C, initial pH 7.5-8.5, C/N ratio 5-20 and salinity 30-40‰, and the nitrification rate of N31 increased with increasing initial [Formula: see text] from 10 to 250 mg/L. Biosecurity assessment with shrimp indicated that strain N31 could be applied in the marine aquaculture industry safely for culture water remediation and effluent treatment. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  15. [Phylogenetic analysis and nitrogen removal characteristics of a heterotrophic nitrifying-aerobic denitrifying bacteria strain from marine environment].

    Science.gov (United States)

    Sun, Xuemei; Li, Qiufen; Zhang, Yan; Liu, Huaide; Zhao, Jun; Qu, Keming

    2012-06-04

    We determined the phylogenetic position of a heterotrophic nitrifying-aerobic denitrifying bacterium X3, and detected its nitrogen removal characteristics for providing evidence to explain the principle of heterotrophic nitrification-aerobic denitrification and to improve the process in purification of marine-culture wastewater. The evolutionary position of the strain was determined based on its morphological, physiological, biochemical characteristics and 16SrRNA gene sequence. The nitrification-denitrification ability of this strain was detected by detecting its nitrogen removal efficiency and growth on different inorganic nitrogen source. Strain X3 was identified as Halomonas sp. It grew optimally at salinity 3%, pH 8.5, C:N 10:1 at 28 degrees C, and it could still survive at 15% salinity. The removal of NH4+ -N, NO2(-) -N and NO3(-) -N was 98.29%, 99.07%, 96.48% respectively within 24 h. When three inorganic nitrogen existed simultaneously, it always utilized ammonia firstly, and the total inorganic nitrogen removal was higher than with only one nitrogen, suggesting that strain X3 has the ability of simultaneous nitrification and denitrification and completing the whole nitrogen removing process. Strain X3 belonged to the genus of Halomonas. It had strong simultaneous nitrification and denitrification capability and could live in high-salinity environment.

  16. Biotechnical leaching of lean ores using heterotrophic microorganisms

    International Nuclear Information System (INIS)

    Schwartz, W.; Naeveke, R.

    1980-01-01

    After reporting briefly on leaching with Thiobacillus, it is discussed whether in those cases where thiobacilli fail to work the limits of microbial leaching are reached or still other groups of microorganisms will be suitable. In this relation the great number of carbon-heterotrophic fungi and bacteria have to be considered which are partly oligotrophic and occur e.g. in weathering biotopes of rocks and minerals and which may even include heavy metals in the dissolving processes of weathering. The active agents are, as far as is known up to now, organic acids which are produced by microorganisms and given off to the medium where they may combine with metals to form water-soluble complex compounds. In order to detect and isolate suitable strains of fungi and bacteria it will be necessary to work out a screening program which proceeds from general to special selections. Experiments to identify the active agents and the conditions of their production will have to follow. It remains still an open question whether such studies will result in technical processes. Mass production processes which are possible with the carbon-autotrophic and acidophilic thiobacilli are less probable than special processes to get hold of rare and economically valuable metals whose extraction would be difficult by other means. (orig.) [de

  17. The Sterilization Effect of Cooperative Treatment of High Voltage Electrostatic Field and Variable Frequency Pulsed Electromagnetic Field on Heterotrophic Bacteria in Circulating Cooling Water

    Science.gov (United States)

    Gao, Xuetong; Liu, Zhian; Zhao, Judong

    2018-01-01

    Compared to other treatment of industrial circulating cooling water in the field of industrial water treatment, high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization technology, an advanced technology, is widely used because of its special characteristics--low energy consumption, nonpoisonous and environmentally friendly. In order to get a better cooling water sterilization effect under the premise of not polluting the environment, some experiments about sterilization of heterotrophic bacteria in industrial circulating cooling water by cooperative treatment of high voltage electrostatic field and variable frequency pulsed electromagnetic field were carried out. The comparison experiment on the sterilization effect of high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization on heterotrophic bacteria in industrial circulating cooling water was carried out by change electric field strength and pulse frequency. The results show that the bactericidal rate is selective to the frequency and output voltage, and the heterotrophic bacterium can only kill under the condition of sweep frequency range and output voltage. When the voltage of the high voltage power supply is 4000V, the pulse frequency is 1000Hz and the water temperature is 30°C, the sterilization rate is 48.7%, the sterilization rate is over 90%. Results of this study have important guiding significance for future application of magnetic field sterilization.

  18. Multi-generational responses of a marine polychaete to a rapid change in seawater pCO2.

    Science.gov (United States)

    Rodríguez-Romero, Araceli; Jarrold, Michael D; Massamba-N'Siala, Gloria; Spicer, John I; Calosi, Piero

    2016-10-01

    Little is known of the capacity that marine metazoans have to evolve under rapid p CO 2 changes. Consequently, we reared a marine polychaete, Ophryotrocha labronica , previously cultured for approximately 33 generations under a low/variable pH regime, under elevated and low p CO 2 for six generations. The strain used was found to be tolerant to elevated p CO 2 conditions. In generations F1 and F2 females' fecundity was significantly lower in the low p CO 2 treatment. However, from generation F3 onwards there were no differences between p CO 2 treatments, indicating that trans-generational effects enabled the restoration and maintenance of reproductive output. Whilst the initial fitness recovery was likely driven by trans-generational plasticity (TGP), the results from reciprocal transplant assays, performed using F7 individuals, made it difficult to disentangle between whether TGP had persisted across multiple generations, or if evolutionary adaptation had occurred. Nonetheless, both are important mechanisms for persistence under climate change. Overall, our study highlights the importance of multi-generational experiments in more accurately determining marine metazoans' responses to changes in p CO 2 , and strengthens the case for exploring their use in conservation, by creating specific p CO 2 tolerant strains of keystone ecosystem species.

  19. Sediment reworking by a polychaete, Perinereis aibuhitensis, in the intertidal sediments of the Gomso Bay, Korea

    Science.gov (United States)

    Koo, Bon Joo; Seo, Jaehwan

    2017-12-01

    Bioturbation, especially sediment reworking by the activities of macroinvertebrates, such as feeding and burrowing, is one of the major processes that affect the physical, chemical, and biological characteristics of marine sediments. Given the importance of sediment reworking, this study was designed to evaluate the sediment reworking rate of a polychaete, Perinereis aibuhitensis, which is dominant in the upper tidal flats on the west coast of Korea, based on quantification of pellet production during spring and fall surveys. The density of individuals was higher in fall than in spring, whereas, due to a difference in the proportion of adults between the two seasons, the morphometric dimensions of the worm and its pellets were significantly longer and heavier in the spring. Hourly pellet production per inhabitant and density were closely related, with pellet production gradually decreasing as density increased. Daily pellet production was much higher in spring than in fall, mostly due to an increase in daytime production. The sediment reworking rate of Perinereis was similar in the two seasons in which observations were made and depended on its density and the sediment reworking rate per individual. The overall sediment reworking rate of Perinereis was 31 mm yr-1 based on its density in the study area.

  20. High current densities enable exoelectrogens to outcompete aerobic heterotrophs for substrate

    KAUST Repository

    Ren, Lijiao

    2014-08-05

    © 2014 Wiley Periodicals, Inc. Chemical oxygen demand (COD) removal rates could be described by first-order kinetics with respect to COD concentration at different current densities, even under open circuit conditions with no current generation. The COD concentration was reduced more quickly with current generation due to the greater consumption of substrate by exoelectrogens, and less substrate was lost to aerobic heterotrophs. Higher current densities enabled exoelectrogens to outcompete aerobic heterotrophs for substrate, allowing for increased coulombic efficiencies with current densities. © 2014 Wiley Periodicals, Inc. In mixed-culture microbial fuel cells (MFCs), exoelectrogens and other microorganisms compete for substrate. It has previously been assumed that substrate losses to other terminal electron acceptors over a fed-batch cycle, such as dissolved oxygen, are constant. However, a constant rate of substrate loss would only explain small increases in coulombic efficiencies (CEs, the fraction of substrate recovered as electrical current) with shorter cycle times, but not the large increases in CE that are usually observed with higher current densities and reduced cycle times. To better understand changes in CEs, COD concentrations were measured over time in fed-batch, single-chamber, air-cathode MFCs at different current densities (external resistances). COD degradation rates were all found to be first-order with respect to COD concentration, even under open circuit conditions with no current generation (first-order rate constant of 0.14±0.01h-1). The rate of COD removal increased when there was current generation, with the highest rate constant (0.33±0.02h-1) obtained at the lowest external resistance (100Ω). Therefore, as the substrate concentration was reduced more quickly due to current generation, the rate of loss of substrate to non-exoelectrogens decreased due to this first-order substrate-concentration dependence. As a result, coulombic

  1. High current densities enable exoelectrogens to outcompete aerobic heterotrophs for substrate

    KAUST Repository

    Ren, Lijiao; Zhang, Xiaoyuan; He, Weihua; Logan, Bruce E.

    2014-01-01

    © 2014 Wiley Periodicals, Inc. Chemical oxygen demand (COD) removal rates could be described by first-order kinetics with respect to COD concentration at different current densities, even under open circuit conditions with no current generation. The COD concentration was reduced more quickly with current generation due to the greater consumption of substrate by exoelectrogens, and less substrate was lost to aerobic heterotrophs. Higher current densities enabled exoelectrogens to outcompete aerobic heterotrophs for substrate, allowing for increased coulombic efficiencies with current densities. © 2014 Wiley Periodicals, Inc. In mixed-culture microbial fuel cells (MFCs), exoelectrogens and other microorganisms compete for substrate. It has previously been assumed that substrate losses to other terminal electron acceptors over a fed-batch cycle, such as dissolved oxygen, are constant. However, a constant rate of substrate loss would only explain small increases in coulombic efficiencies (CEs, the fraction of substrate recovered as electrical current) with shorter cycle times, but not the large increases in CE that are usually observed with higher current densities and reduced cycle times. To better understand changes in CEs, COD concentrations were measured over time in fed-batch, single-chamber, air-cathode MFCs at different current densities (external resistances). COD degradation rates were all found to be first-order with respect to COD concentration, even under open circuit conditions with no current generation (first-order rate constant of 0.14±0.01h-1). The rate of COD removal increased when there was current generation, with the highest rate constant (0.33±0.02h-1) obtained at the lowest external resistance (100Ω). Therefore, as the substrate concentration was reduced more quickly due to current generation, the rate of loss of substrate to non-exoelectrogens decreased due to this first-order substrate-concentration dependence. As a result, coulombic

  2. The effects of wastewater effluent and river discharge on benthic heterotrophic production, organic biomass and respiration in marine coastal sediments.

    Science.gov (United States)

    Burd, B; Macdonald, T; Bertold, S

    2013-09-15

    We examine effects of high river particulate flux and municipal wastewater effluent on heterotrophic organic carbon cycling in coastal subtidal sediments. Heterotrophic production was a predictable (r(2)=0.95) proportion (56%) of oxidized OC flux and strongly correlated with organic/inorganic flux. Consistent growth efficiencies (36%) occurred at all stations. Organic biomass was correlated with total, OC and buried OC fluxes, but not oxidized OC flux. Near the river, production was modest and biomass high, resulting in low P/B. Outfall deposition resulted in depleted biomass and high bacterial production, resulting in the highest P/B. These patterns explain why this region is production "saturated". The δ(15)N in outfall effluent, sediments and dominant taxa provided insight into where, and which types of organisms feed directly on fresh outfall particulates, on older, refractory material buried in sediments, or utilize chemosynthetic symbiotic bacteria. Results are discussed in the context of declining bottom oxygen conditions along the coast. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  3. Factors governing the pH in a heterotrophic, turbid, tidal estuary

    Science.gov (United States)

    Hofmann, A. F.; Meysman, F. J. R.; Soetaert, K.; Middelburg, J. J.

    2009-01-01

    A method to quantify the influence of kinetically modelled biogeochemical processes on the pH of an ecosystem with time variable acid-base dissociation constants is presented and applied to the heterotrophic, turbid Scheldt estuary (SW Netherlands, N Belgium). Nitrification is identified as the main process governing the pH profile of this estuary, while CO2 degassing and advective-dispersive transport "buffer" the effect of nitrification. CO2 degassing accounts for the largest proton turnover per year in the whole estuary. There is a clear inverse correlation between oxygen turnover and proton turnover. The main driver of long-term changes in the mean estuarine pH from 2001 to 2004 is a changing freshwater flow which influences the pH "directly" via [∑CO2] and [TA] and to a significant amount also "indirectly" via [∑NH4+] and the nitrification rates in the estuary.

  4. The complete genome sequence of Staphylothermus marinus reveals differences in sulfur metabolism among heterotrophic Crenarchaeota

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, iain J.; Dharmarajan, Lakshmi; Rodriguez, Jason; Hooper, Sean; Porat, Iris; Ulrich, Luke E.; Elkins, James G.; Mavromatis, Kostas; Sun, Hui; Land, Miriam; Lapidus, Alla; Lucas, Susan; Barry, Kerrie; Huber, Harald; Zhulin, Igor B.; Whitman, William B.; Mukhopadhyay, Biswarup; Woese, Carl; Bristow, James; Kyrpides, Nikos

    2008-09-05

    Staphylothermus marinus is an anaerobic, sulfur-reducing peptide fermenter of the archaeal phylum Crenarchaeota. It is the third heterotrophic, obligate sulfur reducing crenarchaeote to be sequenced and provides an opportunity for comparative analysis of the three genomes. The 1.57 Mbp genome of the hyperthermophilic crenarchaeote Staphylothermus marinus has been completely sequenced. The main energy generating pathways likely involve 2-oxoacid:ferredoxin oxidoreductases and ADP-forming acetyl-CoA synthases. S. marinus possesses several enzymes not present in other crenarchaeotes including a sodium ion-translocating decarboxylase likely to be involved in amino acid degradation. S. marinus lacks sulfur-reducing enzymes present in the other two sulfur-reducing crenarchaeotes that have been sequenced - Thermofilum pendens and Hyperthermus butylicus. Instead it has three operons similar to the mbh and mbx operons of Pyrococcus furiosus, which may play a role in sulfur reduction and/or hydrogen production. The two marine organisms, S. marinus and H. butylicus, possess more sodium-dependent transporters than T. pendens and use symporters for potassium uptake while T. pendens uses an ATP-dependent potassium transporter. T. pendens has adapted to a nutrient-rich environment while H. butylicus is adapted to a nutrient-poor environment, and S. marinus lies between these two extremes. The three heterotrophic sulfur-reducing crenarchaeotes have adapted to their habitats, terrestrial vs. marine, via their transporter content, and they have also adapted to environments with differing levels of nutrients. Despite the fact that they all use sulfur as an electron acceptor, they are likely to have different pathways for sulfur reduction.

  5. Gyrodiniellum shiwhaense n. gen., n. sp., A New Planktonic Heterotrophic Dinoflagellate from the Coastal Waters of Western Korea 

    DEFF Research Database (Denmark)

    Kang, Nam Seon; Jeong, Hae Jin; Moestrup, O.

    2011-01-01

    The heterotrophic dinoflagellate Gyrodiniellum shiwhaense n. gen., n. sp. is described from live cells and from cells prepared for light, scanning electron, and transmission electron microscopy. Also, sequences of the small subunit (SSU) and large subunit (LSU) of rDNA have been analyzed. The epi......The heterotrophic dinoflagellate Gyrodiniellum shiwhaense n. gen., n. sp. is described from live cells and from cells prepared for light, scanning electron, and transmission electron microscopy. Also, sequences of the small subunit (SSU) and large subunit (LSU) of rDNA have been analyzed.......3-0.5 x cell length. Cells that were feeding on the dinoflagellate Amphidinium carterae Hulburt were 9.1-21.6 mu m long and 6.6-15.7 mu m wide. Cells of G. shiwhaense contain nematocysts, trichocysts, a peduncle, and pusule systems, but they lack chloroplasts. The SSU rDNA sequence is > 3% different from......., cells of which possess a taeniocyst-nematocyst complex, G. shiwhaense has nematocysts but lacks taeniocysts. It differs from Paragymnodinium shiwhaense Kang, Jeong, Moestrup & Shin by possessing nematocysts with stylets and filaments. Gyrodiniellum shiwhaense n. gen., n. sp. furthermore lacks ocelloids...

  6. Udbredelse af den invasive polychaete Marenzelleria spp. i danske farvande samt effekten på sedimentmiljøet

    DEFF Research Database (Denmark)

    Christoffersen, Kenn L; Banta, Gary Thomas

    De europæiske arter af børsteormen Marenzelleria består af tre siblingearter (M. viridis, M. neglecta og M. arctia). De stammer oprindeligt fra den Nord Amerikanske østkyst og Arktis og har været i den sydlige Østersø siden de tidlige 1980’ere. De har stor tolerance over for svingende salinitet...... genetisk analyse efter metoden beskrevet i Blank et al. 2007 [1]. De genetiske metoder er baseret på PCR/RFLP og bruges i dette projekt til at bestemme udbredelsen af de tre sibling arter i danske farvande. Den quantitative fauna opgørelse, samt de forskellige sediment parametre, såsom organisk indhold og...... Sjælland mangler stadig, men forventes foretaget før mødet. På mødet præsenteres foreløbig data om Marenzellerias udbredelse og sedimentkarakteristika.. [1] Blank M., Laine A.O., Jürss K. and Bastrop R. 2007. Molecular identification key based on PCR/RFLP for three polychaete sibling species of the genus...

  7. Autotrophic and heterotrophic nitrification-anoxic denitrification dominated the anoxic/oxic sewage treatment process during optimization for higher loading rate and energy savings.

    Science.gov (United States)

    Zhang, Xueyu; Zheng, Shaokui; Zhang, Hangyu; Duan, Shoupeng

    2018-04-30

    This study clarified the dominant nitrogen (N)-transformation pathway and the key ammonia-oxidizing microbial species at three loading levels during optimization of the anoxic/oxic (A/O) process for sewage treatment. Comprehensive N-transformation activity analysis showed that ammonia oxidization was performed predominantly by aerobic chemolithotrophic and heterotrophic ammonia oxidization, whereas N 2 production was performed primarily by anoxic denitrification in the anoxic unit. The abundances of ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria, and anaerobic AOB in activated sludge reflected their activities on the basis of high-throughput sequencing data. AOB amoA gene clone libraries revealed that the predominant AOB species in sludge samples shifted from Nitrosomonas europaea (61% at the normal loading level) to Nitrosomonas oligotropha (58% and 81% at the two higher loading levels). Following isolation and sequencing, the predominant culturable heterotrophic AOB in sludge shifted from Agrobacterium tumefaciens (42% at the normal loading level) to Acinetobacter johnsonii (52% at the highest loading level). Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Influence of Asellus aquaticus on Escherichia coli, Klebsiella pneumoniae, Campylobacter jejuni and naturally occurring heterotrophic bacteria in drinking water.

    Science.gov (United States)

    Christensen, Sarah C B; Nissen, Erling; Arvin, Erik; Albrechtsen, Hans-Jørgen

    2012-10-15

    Water lice, Asellus aquaticus (isopoda), frequently occur in drinking water distribution systems where they are a nuisance to consumers and water utilities. Whether they are solely an aesthetic problem or also affect the microbial water quality is a matter of interest. We studied the influence of A. aquaticus on microbial water quality in non-chlorinated drinking water in controlled laboratory experiments. Pure cultures of the indicator organisms Escherichia coli and Klebsiella pneumoniae and the pathogen Campylobacter jejuni as well as naturally occurring heterotrophic drinking water bacteria (measured as heterotrophic plate counts, HPC) were investigated in microcosms at 7 °C, containing non-sterilised drinking water, drinking water sediment and A. aquaticus collected from a non-chlorinated ground water based drinking water supply system. Concentrations of E. coli, K. pneumoniae and C. jejuni decreased over time, following a first order decay with half lives of 5.3, 18.4 and 1.3 days, respectively. A. aquaticus did not affect survival of indicators and pathogens substantially whereas HPC were influenced by presence of dead A. aquaticus. Growth rates increased with an average of 48% for bacteria grown on R-2A agar and an average of 83% for bacteria grown on yeast extract agar when dead A. aquaticus were present compared to no and living A. aquaticus present. A. aquaticus associated E. coli, K. pneumoniae and C. jejuni were measured (up to 25 per living and 500 per dead A. aquaticus) and so were A. aquaticus associated heterotrophic bacteria (>1.8*10(4) CFU per living and >6*10(4) CFU per dead A. aquaticus). A. aquaticus did not serve as an optimised habitat that increased survival of indicators and pathogens, since A. aquaticus associated E. coli, K. pneumoniae and C. jejuni were only measured as long as the bacteria were also present in the water and sediment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Diversity of Heterotrophic Protists from Extremely Hypersaline Habitats.

    Science.gov (United States)

    Park, Jong Soo; Simpson, Alastair G B

    2015-09-01

    Heterotrophic protists (protozoa) are a diverse but understudied component of the biota of extremely hypersaline environments, with few data on molecular diversity within halophile 'species', and almost nothing known of their biogeographic distribution. We have garnered SSU rRNA gene sequences for several clades of halophilic protozoa from enrichments from waters of >12.5% salinity from Australia, North America, and Europe (6 geographic sites, 25 distinct samples). The small stramenopile Halocafeteria was found at all sites, but phylogenies did not show clear geographic clustering. The ciliate Trimyema was recorded from 6 non-European samples. Phylogenies confirmed a monophyletic halophilic Trimyema group that included possible south-eastern Australian, Western Australian and North American clusters. Several halophilic Heterolobosea were detected, demonstrating that Pleurostomum contains at least three relatively distinct clades, and increasing known continental ranges for Tulamoeba peronaphora and Euplaesiobystra hypersalinica. The unclassified flagellate Palustrimonas, found in one Australian sample, proves to be a novel deep-branching alveolate. These results are consistent with a global distribution of halophilic protozoa groups (∼ morphospecies), but the Trimyema case suggests that is worth testing whether larger forms exhibit biogeographic phylogenetic substructure. The molecular detection/characterization of halophilic protozoa is still far from complete at the clade level, let alone the 'species level'. Copyright © 2015 Elsevier GmbH. All rights reserved.

  10. Polychaete/amphipod ratio as an indicator of environmental impact related to offshore oil and gas production along the Norwegian continental shelf.

    Science.gov (United States)

    Andrade, Hector; Renaud, Paul E

    2011-12-01

    Benthic faunal data is regularly collected worldwide to assess the ecological quality of marine environments. Recently, there has been renewed interest in developing biological indices able to identify environmental status and potential anthropogenic impacts. In this paper we evaluate the performance of a general polychaete/amphipod ratio along the Norwegian continental shelf as an environmental indicator for offshore oil and gas impacts. Two main trends are apparent: first, a contamination gradient is discernible from where production takes place compared to stations 10,000 m away. Second, the quality of the marine environment has improved over time. These results are consistent with monitoring reports employing a combination of uni- and multi-variate statistics. Thus, we consider this ratio as a relatively simple, useful and potentially cost-effective complement to other more demanding assessment techniques. Because of its strong theoretical basis, it may also be useful for detecting ecological change as a result of other activities. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. The effects of chronic radiation on reproductive success of the polychaete worm Neanthes arenaceodentata

    International Nuclear Information System (INIS)

    Harrison, F.L.; Anderson, S.L.

    1988-12-01

    The effects of lifetime exposure to chronic irradiation on reproductive success were assessed for laboratory populations of the polychaete worm Neanthes arenaceodentata. Lifetime exposure was initiated upon the spawning of the P 1 female and was terminated upon spawning of the F 1 female. Groups of experimental worms received either no radiation (controls) or 0.19, 2.1, or 17 mGy/h. The total dose received by the worms was either background or approximately 0.55, 6.5, or 54 Gy, respectively. The broods from the F 1 mated pairs were sacrificed before hatching occurred, and information was obtained on brood size, on the number of normal and abnormal embryos, and on the number of embryos that were living, dying, and dead. The mean number of embryos in the broods from the F 1 females exposed to lifetime radiation of 0.19 and 2.1 mGy/h was not significantly different from the mean number of embryos from control females; however, the mean number of embryos was different from those F 1 females exposed to 17 mGy/h. There was a significant reduction in the number of live embryos in the broods from the F 1 mated pairs that were exposed to the lowest dose rate given, 0.19 mGy/h, as well as those exposed to 2.1 and 17 mGy/h. Also, increased percentages of abnormal embryos were determined in the broods of all the radiation-exposed groups. 39 refs., 10 figs., 15 tabs

  12. Performance of heterotrophic partial denitrification under feast-famine condition of electron donor: a case study using acetate as external carbon source.

    Science.gov (United States)

    Gong, Lingxiao; Huo, Mingxin; Yang, Qing; Li, Jun; Ma, Bin; Zhu, Rulong; Wang, Shuying; Peng, Yongzhen

    2013-04-01

    Recently, the combination of anammox and post heterotrophic partial denitrification (nitrate to nitrite) was increasingly popular to treat anammox effluent with excessive nitrate, whereas achieving nitrite accumulation stably was a major bottleneck for post-denitrification. This work focused on the performance of heterotrophic partial denitrification under acetate feast-famine condition. The results showed that readily biodegradable COD to nitrate (RBCOD/NO3(-)) ratio of 2.5 facilitated an ideal nitrite accumulation ratio (NAR) of 71.7% under complete nitrate reduction. When RBCOD/NO3(-) ratio was below 3.5, in terms of efficiency and nitrite accumulation, higher NAR obtained during exogenous denitrification identified that the external acetate depletion was the optimal ending point of denitrification, which could be indicated by pH accurately. The indication of pH realized NAR of 60% ideally under batch-flow mode with RBCOD/NO3(-) ratio of 2.7, which might promote the scale-up of partial denitrification. Furthemore, alkaline environment (pH 9.0-9.6) repressed N2O emission even during endogenous denitrification. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Draft genome sequence of Microbacterium oleivorans strain Wellendorf implicates heterotrophic versatility and bioremediation potential

    Directory of Open Access Journals (Sweden)

    Anton P. Avramov

    2016-12-01

    Full Text Available Microbacterium oleivorans is a predominant member of hydrocarbon-contaminated environments. We here report on the genomic analysis of M. oleivorans strain Wellendorf that was isolated from an indoor door handle. The partial genome of M. oleivorans strain Wellendorf consists of 2,916,870 bp of DNA with 2831 protein-coding genes and 49 RNA genes. The organism appears to be a versatile mesophilic heterotroph potentially capable of hydrolysis a suite of carbohydrates and amino acids. Genomic analysis revealed metabolic versatility with genes involved in the metabolism and transport of glucose, fructose, rhamnose, galactose, xylose, arabinose, alanine, aspartate, asparagine, glutamate, serine, glycine, threonine and cysteine. This is the first detailed analysis of a Microbacterium oleivorans genome.

  14. Effect of mercury on taurine transport by the red blood cells of the marine polychaete, Glycera dibranchiata

    International Nuclear Information System (INIS)

    Chen, C.W.; Preston, R.L.

    1987-01-01

    The objective of this study was to characterize the effects of heavy metal exposure on the transport of the amino acid, 14 C-taurine, by the hemoglobin containing coelomocytes (red blood cells) of the marine polychaete, Glycera dibranchiata. Glycera has been used previously in studies on heavy metal absorption. Glycera red cells (RBCs) were used for this study because they contain a high concentration of taurine (190 mM) which has been implicated as a major osmolyte in cellular volume regulation in marine invertebrates. Taurine also appears to participate in osmoregulation of mammalian heart and brain tissue. The coelomic fluid bathing Glycera RBCs typically contains taurine at considerably lower concentrations (0.2 mM). The standing gradients (intracellular conc./extracellular conc.) for amino acids ranges from 40:1 for lysine to 950:1 for taurine. Preliminary experiments demonstrated that the maintenance of the large standing gradient for taurine was apparently due to the presence of a specific Na and Cl dependent taurine transport system in these cells. The fact that Glycera RBCs actively maintain large taurine gradients suggests that this tissue should be an excellent one to use in analysis of the mechanisms of heavy metal interaction with taurine transport systems

  15. Characterization and expression of calmodulin gene during larval settlement and metamorphosis of the polychaete Hydroides elegans

    KAUST Repository

    Chen, Zhangfan

    2012-08-01

    The polychaete . Hydroides elegans (Serpulidae, Lophotrochozoa) is a problematic marine fouling organism in most tropical and subtropical coastal environment. Competent larvae of . H. elegans undergo the transition from the swimming larval stage to the sessile juvenile stage with substantial morphological, physiological, and behavior changes. This transition is often referred to as larval settlement and metamorphosis. In this study, we examined the possible involvement of calmodulin (CaM) - a multifunctional calcium metabolism regulator, in the larval settlement and metamorphosis of . H. elegans. A full-length . CaM cDNA was successfully cloned from . H. elegans (. He-CaM) and it contained an open reading frame of 450. bp, encoding 149 amino acid residues. It was highly expressed in 12. h post-metamorphic juveniles, and remained high in adults. . In situ hybridization conducted in competent larvae and juveniles revealed that . He-CaM gene was continuously expressed in the putative growth zones, branchial rudiments, and collar region, suggesting that . He-CaM might be involved in tissue differentiation and development. Our subsequent bioassay revealed that the CaM inhibitor W7 could effectively inhibit larval settlement and metamorphosis, and cause some morphological defects of unsettled larvae. In conclusion, our results revealed that CaM has important functions in the larval settlement and metamorphosis of . H. elegans. © 2012 Elsevier Inc..

  16. Pore-scale investigation on the response of heterotrophic respiration to moisture conditions in heterogeneous soils

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Zhifeng; Liu, Chongxuan; Todd-Brown, Katherine E.; Liu, Yuanyuan; Bond-Lamberty, Ben; Bailey, Vanessa L.

    2016-11-15

    The relationship between microbial respiration rate and soil moisture content is an important property for understanding and predicting soil organic carbon degradation, CO2 production and emission, and their subsequent effects on climate change. This paper reports a pore-scale modeling study to investigate the response of heterotrophic respiration to moisture conditions in soils and to evaluate various factors that affect this response. X-ray computed tomography was used to derive soil pore structures, which were then used for pore-scale model investigation. The pore-scale results were then averaged to calculate the effective respiration rates as a function of water content in soils. The calculated effective respiration rate first increases and then decreases with increasing soil water content, showing a maximum respiration rate at water saturation degree of 0.75 that is consistent with field and laboratory observations. The relationship between the respiration rate and moisture content is affected by various factors, including pore-scale organic carbon bioavailability, the rate of oxygen delivery, soil pore structure and physical heterogeneity, soil clay content, and microbial drought resistivity. Simulations also illustrates that a larger fraction of CO2 produced from microbial respiration can be accumulated inside soil cores under higher saturation conditions, implying that CO2 flux measured on the top of soil cores may underestimate or overestimate true soil respiration rates under dynamic moisture conditions. Overall, this study provides mechanistic insights into the soil respiration response to the change in moisture conditions, and reveals a complex relationship between heterotrophic microbial respiration rate and moisture content in soils that is affected by various hydrological, geochemical, and biophysical factors.

  17. Relationships between meiofaunal biodiversity and prokaryotic heterotrophic production in different tropical habitats and oceanic regions.

    Science.gov (United States)

    Pusceddu, Antonio; Gambi, Cristina; Corinaldesi, Cinzia; Scopa, Mariaspina; Danovaro, Roberto

    2014-01-01

    Tropical marine ecosystems are among the most diverse of the world oceans, so that assessing the linkages between biodiversity and ecosystem functions (BEF) is a crucial step to predict consequences of biodiversity loss. Most BEF studies in marine ecosystems have been carried out on macrobenthic diversity, whereas the influence of the meiofauna on ecosystem functioning has received much less attention. We compared meiofaunal and nematode biodiversity and prokaryotic heterotrophic production across seagrass, mangrove and reef sediments in the Caribbean, Celebes and Red Seas. For all variables we report the presence of differences among habitats within the same region, and among regions within the same habitat. In all regions, the richness of meiofaunal taxa in reef and seagrass sediments is higher than in mangrove sediments. The sediments of the Celebes Sea show the highest meiofaunal biodiversity. The composition of meiofaunal assemblages varies significantly among habitats in the same region. The nematode beta diversity among habitats within the same region is higher than the beta diversity among regions. Although one site per habitat was considered in each region, these results suggest that the composition of meiofaunal assemblages varies primarily among biogeographic regions, whereas the composition of nematode assemblages varies more considerably among habitats. Meiofauna and nematode biodiversity and prokaryotic heterotrophic production, even after the removal of covariate effects linked with longitude and the quantity and nutritional quality of organic matter, are positively and linearly linked both across regions and within each habitat type. Our results confirm that meiofauna and nematode biodiversity may influence benthic prokaryotic activity, which, in turn, implies that diversity loss could have negative impacts on ecosystem functioning in these systems.

  18. Relationships between meiofaunal biodiversity and prokaryotic heterotrophic production in different tropical habitats and oceanic regions.

    Directory of Open Access Journals (Sweden)

    Antonio Pusceddu

    Full Text Available Tropical marine ecosystems are among the most diverse of the world oceans, so that assessing the linkages between biodiversity and ecosystem functions (BEF is a crucial step to predict consequences of biodiversity loss. Most BEF studies in marine ecosystems have been carried out on macrobenthic diversity, whereas the influence of the meiofauna on ecosystem functioning has received much less attention. We compared meiofaunal and nematode biodiversity and prokaryotic heterotrophic production across seagrass, mangrove and reef sediments in the Caribbean, Celebes and Red Seas. For all variables we report the presence of differences among habitats within the same region, and among regions within the same habitat. In all regions, the richness of meiofaunal taxa in reef and seagrass sediments is higher than in mangrove sediments. The sediments of the Celebes Sea show the highest meiofaunal biodiversity. The composition of meiofaunal assemblages varies significantly among habitats in the same region. The nematode beta diversity among habitats within the same region is higher than the beta diversity among regions. Although one site per habitat was considered in each region, these results suggest that the composition of meiofaunal assemblages varies primarily among biogeographic regions, whereas the composition of nematode assemblages varies more considerably among habitats. Meiofauna and nematode biodiversity and prokaryotic heterotrophic production, even after the removal of covariate effects linked with longitude and the quantity and nutritional quality of organic matter, are positively and linearly linked both across regions and within each habitat type. Our results confirm that meiofauna and nematode biodiversity may influence benthic prokaryotic activity, which, in turn, implies that diversity loss could have negative impacts on ecosystem functioning in these systems.

  19. Heterotrophs are key contributors to nitrous oxide production in mixed liquor under low C-to-N ratios during nitrification - batch experiments and modelling

    DEFF Research Database (Denmark)

    Domingo Felez, Carlos; Pellicer i Nàcher, Carles; Petersen, Morten S.

    2017-01-01

    Nitrous oxide (N2O), a by-product of biological nitrogen removal during wastewater treatment, is produced by ammonia-oxidizing bacteria (AOB) and heterotrophic denitrifying bacteria (HB). Mathematical models are used to predict N2O emissions, often including AOB as the main N2O producer. Several...

  20. Viral lysis of Phaeocystis pouchetii: implications for algal population dynamics and heterotrophic C, N and P cycling

    DEFF Research Database (Denmark)

    Haaber, Jakob Brandt Borup; Middelboe, Mathias

    2009-01-01

    in the microbial food web was associated with significant N and P mineralization, supporting the current view that viral lysates can be an important source of inorganic nutrients in marine systems. In the presence of R. salina, the generated NH(4)(+) supported 11% of the observed R. salina growth. Regrowth...... of virus-resistant P. pouchetii following cell lysis was observed in long-term incubations (150 days), and possibly influenced by nutrient availability and competition from R. salina. The observed impact of viral activity on autotrophic and heterotrophic processes provides direct experimental evidence...

  1. Microbial pollution indicators and culturable heterotrophic bacteria in a Mediterranean area (Southern Adriatic Sea Italian coasts)

    Science.gov (United States)

    Stabili, L.; Cavallo, R. A.

    2011-05-01

    In the present study we evaluated the degree of microbial water pollution along the coast line between Brindisi and Santa Maria di Leuca (Southern Adriatic Sea) as well as the culturable heterotrophic bacteria abundances and biodiversity in relation to the microbiological quality of the water. A total of 3773 colonies were isolated, subcultured and identified by several morphological, cultural and biochemical methods including the standardized API 20 E and API 20 NE tests. Along the examined coastal tract the microbial pollution indicators were always below the tolerance limits for bathing waters defined by the CEE directive, suggesting a good sanitary quality. Concerning culturable heterotrophic bacteria, different temporal density trends were observed in the four sites in relation to their geographical position. A positive relationship between the bacterial abundances and the temperature was observed in S. Cataldo and Otranto. The culturable bacterial community was mainly composed of the genera Aeromonas, Pseudomonas, Photobacterium and Flavobacterium. The Enterobacteriaceae family represented a conspicuous component of the bacterial community too. Bacilli were predominant among the Gram-positive bacteria. Of interest is the isolation of yeasts (2% at the surface and 1% at the bottom) taking into account their capability of biodegradation of various materials. Because of the low level of microbial pollution recorded, our results are indicative of the natural variation and diversity of the culturable bacterial community in such an oligotrophic ecosystem and could represent a good point of comparison with other ecosystems as well as a baseline for long term studies aimed to evaluate the effects of environmental fluctuations and human impacts on this aspect of biodiversity in coastal areas.

  2. Metabolic flux analysis of heterotrophic growth in Chlamydomonas reinhardtii.

    Directory of Open Access Journals (Sweden)

    Nanette R Boyle

    Full Text Available Despite the wealth of knowledge available for C. reinhardtii, the central metabolic fluxes of growth on acetate have not yet been determined. In this study, 13C-metabolic flux analysis (13C-MFA was used to determine and quantify the metabolic pathways of primary metabolism in C. reinhardtii cells grown under heterotrophic conditions with acetate as the sole carbon source. Isotopic labeling patterns of compartment specific biomass derived metabolites were used to calculate the fluxes. It was found that acetate is ligated with coenzyme A in the three subcellular compartments (cytosol, mitochondria and plastid included in the model. Two citrate synthases were found to potentially be involved in acetyl-coA metabolism; one localized in the mitochondria and the other acting outside the mitochondria. Labeling patterns demonstrate that Acetyl-coA synthesized in the plastid is directly incorporated in synthesis of fatty acids. Despite having a complete TCA cycle in the mitochondria, it was also found that a majority of the malate flux is shuttled to the cytosol and plastid where it is converted to oxaloacetate providing reducing equivalents to these compartments. When compared to predictions by flux balance analysis, fluxes measured with 13C-MFA were found to be suboptimal with respect to biomass yield; C. reinhardtii sacrifices biomass yield to produce ATP and reducing equivalents.

  3. [Isolation, Identification and Nitrogen Removal Characteristics of a Heterotrophic Nitrification-Aerobic Denitrification Strain y3 Isolated from Marine Environment].

    Science.gov (United States)

    Sun, Qing-hua; Yu, De-shuang; Zhang, Pei-yu; Lin, Xue-zheng; Xu, Guang-yao; Li, Jin

    2016-03-15

    A heterotrophic nitrification--aerobic denitrification bacterium named y3 was isolated from the sludge of Jiaozhou Bay using the enrichment medium with seawater as the matrix. It was identified as Pseudomonas sp. based on the morphological observation, physiological experiments and sequence analysis of 16S rRNA. The experiment results showed that the optimal carbon resource was sodium citrate, the optimal pH was 7.0, and the optimal C/N was 13. The strain could use NH₄Cl, NaNO₂ and KNO₃ as sole nitrogen source, and the removal efficiencies were 98.69%, 78.38% and 72.95% within 20 hours, respectively. There was no nitrate and nitrite accumulation during the heterotrophic nitrification process. Within 20 hours, the nitrogen removal efficiencies were 99.56%, 99.75% and 99.41%, respectively, in the mixed system with NO₃⁻-N: NO²⁻-N of 2:1, 1:1 and 1:2. When the NH₄⁺-N: NO₃⁻-N ratios were 2: 1 , 1: 1 , 1: 2, the nitrogen removal efficiencies were all 100% . When the NH₄⁺-N:NO₂⁻-N ratios were 2:1,1:1,1:2, the nitrogen removal efficiencies were 90.43%, 92.79% and 99.96%, respectively. They were higher than those with single nitrogen source. As a result, strain y3 had good nitrogen removal performance in high saline wastewater treatment.

  4. Biodiversity and biogeographic relationships of the polychaete fauna in French Atlantic and Mediterranean waters

    Directory of Open Access Journals (Sweden)

    Jean-Claude Dauvin

    2006-12-01

    Full Text Available A survey of the literature, including the recent systematic reviews, reveals that 934 polychaete species have been recorded in French Atlantic (including the English Channel and Mediterranean marine waters, including 818 species living on the continental shelf and 116 species that are strictly bathyal. These 934 species belong to 71 families, among which the Syllidae is the most diverse (97 species, followed by the Serpulidae (69 species, Spionidae and Phyllodocidae, each with more than 40 species. Forty-four families have fewer than 10 species recorded in each. The total number of species is spread over 11 continental shelf areas as well as the Atlantic and Mediterranean bathyal depths. In terms of species diversity, the richest areas are the Mediterranean coasts of Provence-Côte d’Azur (507 species and Languedoc-Roussillon (483 species, the western part of the English Channel (402 species, and the southern part of the Bay of Biscay (343 species. The lowest numbers of species were recorded in the eastern English Channel, due to an impoverishment of all the fauna in this part of the Channel. Other areas—for example, the Iroise Sea, the coast of Corsica and Mediterranean bathyal depths—also show low numbers, but this may only reflect the fact that insufficient information about these areas is available. A similarity analysis of 13 areas distinguishes four distinct faunal groups, each specific to one of four general locations: (1 the bathyal Atlantic and Mediterranean zones, including the coast of Corsica, (2 the two Mediterranean coastal areas (Provence-Côte d’Azur and Languedoc-Roussillon, (3 the four zones of the Atlantic continental shelf, and (4 the English Channel. The combined species can be separated into 17 different biogeographic groups.

  5. Effects of Soil Moisture on the Temperature Sensitivity of Soil Heterotrophic Respiration: A Laboratory Incubation Study

    Science.gov (United States)

    Zhou, Weiping; Hui, Dafeng; Shen, Weijun

    2014-01-01

    The temperature sensitivity (Q10) of soil heterotrophic respiration (Rh) is an important ecological model parameter and may vary with temperature and moisture. While Q10 generally decreases with increasing temperature, the moisture effects on Q10 have been controversial. To address this, we conducted a 90-day laboratory incubation experiment using a subtropical forest soil with a full factorial combination of five moisture levels (20%, 40%, 60%, 80%, and 100% water holding capacity - WHC) and five temperature levels (10, 17, 24, 31, and 38°C). Under each moisture treatment, Rh was measured several times for each temperature treatment to derive Q10 based on the exponential relationships between Rh and temperature. Microbial biomass carbon (MBC), microbial community structure and soil nutrients were also measured several times to detect their potential contributions to the moisture-induced Q10 variation. We found that Q10 was significantly lower at lower moisture levels (60%, 40% and 20% WHC) than at higher moisture level (80% WHC) during the early stage of the incubation, but became significantly higher at 20%WHC than at 60% WHC and not significantly different from the other three moisture levels during the late stage of incubation. In contrast, soil Rh had the highest value at 60% WHC and the lowest at 20% WHC throughout the whole incubation period. Variations of Q10 were significantly associated with MBC during the early stages of incubation, but with the fungi-to-bacteria ratio during the later stages, suggesting that changes in microbial biomass and community structure are related to the moisture-induced Q10 changes. This study implies that global warming’s impacts on soil CO2 emission may depend upon soil moisture conditions. With the same temperature rise, wetter soils may emit more CO2 into the atmosphere via heterotrophic respiration. PMID:24647610

  6. Pathogenic features of heterotrophic plate count bacteria from drinking-water boreholes.

    Science.gov (United States)

    Horn, Suranie; Pieters, Rialet; Bezuidenhout, Carlos

    2016-12-01

    Evidence suggests that heterotrophic plate count (HPC) bacteria may be hazardous to humans with weakened health. We investigated the pathogenic potential of HPC bacteria from untreated borehole water, consumed by humans, for: their haemolytic properties, the production of extracellular enzymes such as DNase, proteinase, lipase, lecithinase, hyaluronidase and chondroitinase, the effect simulated gastric fluid has on their survival, as well as the bacteria's antibiotic-susceptible profile. HuTu-80 cells acted as model for the human intestine and were exposed to the HPC isolates to determine their effects on the viability of the cells. Several HPC isolates were α- or β-haemolytic, produced two or more extracellular enzymes, survived the SGF treatment, and showed resistance against selected antibiotics. The isolates were also harmful to the human intestinal cells to varying degrees. A novel pathogen score was calculated for each isolate. Bacillus cereus had the highest pathogen index: the pathogenicity of the other bacteria declined as follows: Aeromonas taiwanensis > Aeromonas hydrophila > Bacillus thuringiensis > Alcaligenes faecalis > Pseudomonas sp. > Bacillus pumilus > Brevibacillus sp. > Bacillus subtilis > Bacillus sp. These results demonstrated that the prevailing standards for HPCs in drinking water may expose humans with compromised immune systems to undue risk.

  7. Differential interactions between the nematocyst-bearing mixotrophic dinoflagellate Paragymnodinium shiwhaense and common heterotrophic protists and copepods: Killer or prey.

    Science.gov (United States)

    Jeong, Hae Jin; Kim, Jae Seong; Lee, Kyung Ha; Seong, Kyeong Ah; Yoo, Yeong Du; Kang, Nam Seon; Kim, Tae Hoon; Song, Jae Yoon; Kwon, Ji Eun

    2017-02-01

    To investigate interactions between the nematocyst-bearing mixotrophic dinoflagellate Paragymnodinium shiwhaense and different heterotrophic protist and copepod species, feeding by common heterotrophic dinoflagellates (Oxyrrhis marina and Gyrodinium dominans), naked ciliates (Strobilidium sp. approximately 35μm in cell length and Strombidinopsis sp. approximately 100μm in cell length), and calanoid copepods Acartia spp. (A. hongi and A. omorii) on P. shiwhaense was explored. In addition, the feeding activities of P. shiwhaense on these heterotrophic protists were investigated. Furthermore, the growth and ingestion rates of O. marina, G. dominans, Strobilidium sp., Strombidinopsis sp., and Acartia spp. as a function of P. shiwhaense concentration were measured. O. marina, G. dominans, and Strombidinopsis sp. were able to feed on P. shiwhaense, but Strobilidium sp. was not. However, the growth rates of O. marina, G. dominans, Strobilidium sp., and Strombidinopsis sp. feeding on P. shiwhaense were very low or negative at almost all concentrations of P. shiwhaense. P. shiwhaense frequently fed on O. marina and Strobilidium sp., but did not feed on Strombidinopsis sp. and G. dominans. G. dominans cells swelled and became dead when incubated with filtrate from the experimental bottles (G. dominans+P. shiwhaense) that had been incubated for one day. The ingestion rates of O. marina, G. dominans, and Strobilidium sp. on P. shiwhaense were almost zero at all P. shiwhaense concentrations, while those of Strombidinopsis sp. increased with prey concentration. The maximum ingestion rate of Strombidinopsis sp. on P. shiwhaense was 5.3ngC predator -1 d -1 (41 cells predator -1 d -1 ), which was much lower than ingestion rates reported in the literature for other mixotrophic dinoflagellate prey species. With increasing prey concentrations, the ingestion rates of Acartia spp. on P. shiwhaense increased up to 930ngCml -1 (7180cellsml -1 ) at the highest prey concentration. The

  8. Alien reef-building polychaete drives long-term changes in invertebrate biomass and diversity in a small, urban estuary

    Science.gov (United States)

    McQuaid, K. A.; Griffiths, C. L.

    2014-02-01

    Two of the greatest threats to native biodiversity are the construction of artificial structures in natural environments and the introduction of invasive species. As the development and urbanisation of estuaries continues at an increasing rate worldwide, these environments are being simultaneously affected by these threats. This study quantifies the spread of an invasive reef-building polychaete, Ficopomatus enigmaticus, in a small, highly manipulated urban estuary in South Africa and investigates its role as an ecosystem engineer. Anthropogenic changes to the Zandvlei Estuary, including construction of a rubble weir and canalisation near the estuary mouth, construction of an extensive marina development and hardening of the banks with concrete, have facilitated the expansion of F. enigmaticus. The standing stock of F. enigmaticus increased from 13.69 t, as measured in 1986, to 50.03 t in 2012, due both to increase in the total area colonised and standing stock per m2. Since F. enigmaticus reefs support a greater biomass of infauna than adjacent sandy areas, total invertebrate biomass in the estuary is estimated to have increased from less than 0.30 t in 1942, to over 56.80 t in 2012, due mainly to hardening of banks in parts of the main estuary with concrete and construction of a marina system. A positive correlation between reef mass and infaunal biomass, density and diversity was also found.

  9. Cold-Active, Heterotrophic Bacteria from the Highly Oligotrophic Waters of Lake Vanda, Antarctica

    Directory of Open Access Journals (Sweden)

    Nicole A. Vander Schaaf

    2015-07-01

    Full Text Available The permanently ice-covered lakes of the McMurdo Dry Valleys, Antarctica are distinctive ecosystems that consist strictly of microbial communities. In this study, water samples were collected from Lake Vanda, a stratified Dry Valley lake whose upper waters (from just below the ice cover to nearly 60 m are highly oligotrophic, and used to establish enrichment cultures. Six strains of psychrotolerant, heterotrophic bacteria were isolated from lake water samples from a depth of 50 or 55 m. Phylogenetic analyses showed the Lake Vanda strains to be species of Nocardiaceae, Caulobacteraceae, Sphingomonadaceae, and Bradyrhizobiaceae. All Lake Vanda strains grew at temperatures near or below 0 °C, but optimal growth occurred from 18 to 24 °C. Some strains showed significant halotolerance, but no strains required NaCl for growth. The isolates described herein include cold-active species not previously reported from Dry Valley lakes, and their physiological and phylogenetic characterization broadens our understanding of these limnologically unique lakes.

  10. Production of heterotrophic bacteria inhabiting macroscopic organic aggregates (marine snow) from surface waters

    International Nuclear Information System (INIS)

    Alldredge, A.L.; Cole, J.J.; Caron, D.A.

    1986-01-01

    Macroscopic detrital aggregates, known as marine snow, are a ubiquitous and abundant component of the marine pelagic zone. Descriptions of microbial communities occurring at densities 2-5 orders of magnitude higher on these particles than in the surrounding seawater have led to the suggestion that marine snow may be a site of intense heterotrophic activity. The authors tested this hypothesis using incorporation of [ 3 H]thymidine into macromolecules as a measure of bacterial growth occurring on marine snow from oceanic waters in the North Atlantic and from neritic waters off southern California. Abundances of marine snow ranged from 0.1 to 4.3 aggregates per liter. However, only 0.1-4% ration per cell on aggregates was generally equal to or lower than that of bacteria found free-living in the surrounding seawater, indicating that attached bacteria were not growing more rapidly than free-living bacteria. Bacteria inhabiting aggregates were up to 25 times larger than free-living forms

  11. Heterotrophic respiration in drained tropical peat temperatures influenced by shading gradient

    Science.gov (United States)

    Jauhiainen, Jyrki; Kerojoki, Otto; Silvennoinen, Hanna; Limin, Suwido; Vasander, Harri

    2015-04-01

    Lowland peatlands in Southeast Asia constitute a highly concentrated carbon (C) pool of global significance. These peatlands have formed over periods of several millennia by forest vegetation tolerant to flooding and poor substrates. Uncontrollable drainage and reoccurring wild fires in lack of management after removal of forest cover has impaired the C-storing functions in large reclaimed areas. Intergovernmental Panel on Climate Change (IPCC) reporting sees drained tropical organic soils as one of the largest greenhouse gas emissions releasing terrestrial systems. Vast areas of deforested tropical peatlands do not receive noteworthy shading by vegetation, which increases the amount of solar radiation reaching the peat surface. We studied heterotrophic carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) fluxes in tropical peat in conditions, where; (i) peat temperatures were modified by artificial shading (no shade, 28%, 51% and 90% from the full sun exposure), (ii) root respiration was minimized, (iii) nutrient availability for peat decomposer community was changed (NPK fertilization of 0 and 313 kg ha-1). The experiment was repeated at two over 20 years ago drained fallow agricultural- and degraded sites in Central Kalimantan, Indonesia. Enhanced shading created a lasting decrease in peat temperatures, and decreased diurnal temperature fluctuations, in comparison to less shaded plots. The largest peat temperature difference was between the unshaded and 90% shaded peat surface, where the average temperatures within the topmost 50-cm peat profile differed 3 °C, and diurnal temperatures at 5 cm depth varied up to 4.2 °C in the unshaded and 0.4 °C in the 90% shaded conditions. Highest impacts on the heterotrophic CO2 fluxes caused by the treatments were on agricultural land, where 90% shading from the full exposure resulted in a 33% lower CO2 emission average on the unfertilised plots and a 66% lower emission average on the fertilised plots. Correlation

  12. Survival of marine heterotrophic flagellates isolated from the surface and the deep sea at high hydrostatic pressure: Literature review and own experiments

    Science.gov (United States)

    Živaljić, Suzana; Schoenle, Alexandra; Nitsche, Frank; Hohlfeld, Manon; Piechocki, Julia; Reif, Farina; Shumo, Marwa; Weiss, Alexandra; Werner, Jennifer; Witt, Madeleine; Voss, Janine; Arndt, Hartmut

    2018-02-01

    Although the abyssal seafloor represents the most common benthic environment on Earth, eukaryotic microbial life at abyssal depths is still an uncharted territory. This is in striking contrast to their potential importance regarding the material flux and bacteria consumption in the deep sea. Flagellate genotypes determined from sedimentary DNA deep-sea samples might originate from vital deep-sea populations or from cysts of organisms sedimented down from surface waters. The latter one may have never been active under deep-sea conditions. We wanted to analyze the principal ability of cultivable heterotrophic flagellates of different phylogenetic groups (choanoflagellates, ancyromonads, euglenids, kinetoplastids, bicosoecids, chrysomonads, and cercozoans) to survive exposure to high hydrostatic pressure (up to 670 bar). We summarized our own studies and the few available data from literature on pressure tolerances of flagellates isolated from different marine habitats. Our results demonstrated that many different flagellate species isolated from the surface waters and deep-sea sediments survived drastic changes in hydrostatic pressure. Barophilic behavior was also recorded for several species isolated from the deep sea indicating their possible genetic adaptation to high pressures. This is in accordance with records of heterotrophic flagellates present in environmental DNA surveys based on clone libraries established for deep-sea environments.

  13. Virus-mediated transfer of nitrogen from heterotrophic bacteria to phytoplankton

    Science.gov (United States)

    Shelford, Emma J.; Suttle, Curtis A.

    2018-02-01

    Lytic infection of bacteria by viruses releases nutrients during cell lysis and stimulates the growth of primary producers, but the path by which these nutrients flow from lysates to primary producers has not been traced. This study examines the remineralisation of nitrogen (N) from Vibrio lysates by heterotrophic bacterioplankton and its transfer to primary producers. In laboratory trials, Vibrio sp. strain PWH3a was infected with a lytic virus (PWH3a-P1) and the resulting 36.0 µmol L-1 of dissolved organic N (DON) in the lysate was added to cultures containing cyanobacteria (Synechococcus sp. strain DC2) and a natural bacterial assemblage. Based on the increase in cyanobacteria, 74 % (26.5 µmol L-1 N) of the DON in the lysate was remineralised and taken up. Lysate from Vibrio sp. strain PWH3a labeled with 15NH4+ was also added to seawater containing natural microbial communities, and in four field experiments, stable isotope analysis indicated that the uptake of 15N was 0.09 to 0.70 µmol N µg-1 of chlorophyll a. The results from these experiments demonstrate that DON from lysate can be efficiently remineralised and transferred to phytoplankton, and they provide further evidence that the viral shunt is an important link in nitrogen recycling in aquatic systems.

  14. Kinetic modeling of growth and lipid body induction in Chlorella pyrenoidosa under heterotrophic conditions.

    Science.gov (United States)

    Sachdeva, Neha; Kumar, G Dinesh; Gupta, Ravi Prakash; Mathur, Anshu Shankar; Manikandan, B; Basu, Biswajit; Tuli, Deepak Kumar

    2016-10-01

    The aim of the present work was to develop a mathematical model to describe the biomass and (total) lipid productivity of Chlorella pyrenoidosa NCIM 2738 under heterotrophic conditions. Biomass growth rate was predicted by Droop's cell quota model, while changes observed in cell quota (utilization) under carbon excess conditions were used for the modeling and predicting the lipid accumulation rate. The model was simulated under non-limiting (excess) carbon and limiting nitrate concentration and validated with experimental data for the culture grown in batch (flask) mode under different nitrate concentrations. The present model incorporated two modes (growth and stressed) for the prediction of endogenous lipid synthesis/induction and aimed to predict the effect and response of the microalgae under nutrient starvation (stressed) conditions. MATLAB and Genetic Algorithm were employed for the prediction and validation of the model parameters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Diversity and antimicrobial potential of culturable heterotrophic bacteria associated with the endemic marine sponge Arenosclera brasiliensis

    Directory of Open Access Journals (Sweden)

    Cintia P.J. Rua

    2014-06-01

    Full Text Available Marine sponges are the oldest Metazoa, very often presenting a complex microbial consortium. Such is the case of the marine sponge Arenosclera brasiliensis, endemic to Rio de Janeiro State, Brazil. In this investigation we characterized the diversity of some of the culturable heterotrophic bacteria living in association with A. brasiliensis and determined their antimicrobial activity. The genera Endozoicomonas (N = 32, Bacillus (N = 26, Shewanella (N = 17, Pseudovibrio (N = 12, and Ruegeria (N = 8 were dominant among the recovered isolates, corresponding to 97% of all isolates. Approximately one third of the isolates living in association with A. brasiliensis produced antibiotics that inhibited the growth of Bacillus subtilis, suggesting that bacteria associated with this sponge play a role in its health.

  16. Archaea in metazoan diets: implications for food webs and biogeochemical cycling.

    Science.gov (United States)

    Thurber, Andrew R; Levin, Lisa A; Orphan, Victoria J; Marlow, Jeffrey J

    2012-08-01

    Although the importance of trophic linkages, including 'top-down forcing', on energy flow and ecosystem productivity is recognized, the influence of metazoan grazing on Archaea and the biogeochemical processes that they mediate is unknown. Here, we test if: (1) Archaea provide a food source sufficient to allow metazoan fauna to complete their life cycle; (2) neutral lipid biomarkers (including crocetane) can be used to identify Archaea consumers; and (3) archaeal aggregates are a dietary source for methane seep metazoans. In the laboratory, we demonstrated that a dorvilleid polychaete, Ophryotrocha labronica, can complete its life cycle on two strains of Euryarchaeota with the same growth rate as when fed bacterial and eukaryotic food. Archaea were therefore confirmed as a digestible and nutritious food source sufficient to sustain metazoan populations. Both strains of Euryarchaeota used as food sources had unique lipids that were not incorporated into O. labronica tissues. At methane seeps, sulfate-reducing bacteria that form aggregations and live syntrophically with anaerobic-methane oxidizing Archaea contain isotopically and structurally unique fatty acids (FAs). These biomarkers were incorporated into tissues of an endolithofaunal dorvilleid polychaete species from Costa Rica (mean bulk δ(13)C=-92±4‰; polar lipids -116‰) documenting consumption of archaeal-bacterial aggregates. FA composition of additional soft-sediment methane seep species from Oregon and California provided evidence that consumption of archaeal-bacterial aggregates is widespread at methane seeps. This work is the first to show that Archaea are consumed by heterotrophic metazoans, a trophic process we coin as 'archivory'.

  17. Coupling of heterotrophic bacteria to phytoplankton bloom development at different pCO2 levels: a mesocosm study

    Directory of Open Access Journals (Sweden)

    R. Thyrhaug

    2008-07-01

    Full Text Available The predicted rise in anthropogenic CO2 emissions will increase CO2 concentrations and decrease seawater pH in the upper ocean. Recent studies have revealed effects of pCO2 induced changes in seawater chemistry on a variety of marine life forms, in particular calcifying organisms. To test whether the predicted increase in pCO2 will directly or indirectly (via changes in phytoplankton dynamics affect abundance, activities, and community composition of heterotrophic bacteria during phytoplankton bloom development, we have aerated mesocosms with CO2 to obtain triplicates with three different partial pressures of CO2 (pCO2: 350 μatm (1×CO2, 700 μatm (2×CO2 and 1050 μatm (3×CO2. The development of a phytoplankton bloom was initiated by the addition of nitrate and phosphate. In accordance to an elevated carbon to nitrogen drawdown at increasing pCO2, bacterial production (BPP of free-living and attached bacteria as well as cell-specific BPP (csBPP of attached bacteria were related to the C:N ratio of suspended matter. These relationships significantly differed among treatments. However, bacterial abundance and activities were not statistically different among treatments. Solely community structure of free-living bacteria changed with pCO2 whereas that of attached bacteria seemed to be independent of pCO2 but tightly coupled to phytoplankton bloom development. Our findings imply that changes in pCO2, although reflected by changes in community structure of free-living bacteria, do not directly affect bacterial activity. Furthermore, bacterial activity and dynamics of heterotrophic bacteria, especially of attached bacteria, were tightly correlated to phytoplankton development and, hence, may also potentially depend on changes in pCO2.

  18. Recolonization by heterotrophic bacteria after UV irradiation or ozonation of seawater; a simulation of ballast water treatment.

    Science.gov (United States)

    Hess-Erga, Ole-Kristian; Blomvågnes-Bakke, Bente; Vadstein, Olav

    2010-10-01

    Transport of ballast water with ships represents a risk for introduction of foreign species. If ballast water is treated during uptake, there will be a recolonization of the ballast water by heterotrophic bacteria during transport. We investigated survival and succession of heterotrophic bacteria after disinfection of seawater in the laboratory, representing a model system of ballast water treatment and transport. The seawater was exposed to ultraviolet (UV) irradiation, ozone (2 doses) or no treatment, incubated for 16 days and examined with culture-dependent and -independent methods. The number of colony-forming units (CFU) was reduced below the detection level after disinfection with UV and high ozone dose (700 mV), and 1% of the initial level for the low ozone dose (400 mV). After less than 3 days, the CFU was back or above the starting point for the control, UV and low ozone treatment, whereas it took slightly more than 6 days for the high ozone treatment. Disinfection increased substrate availability and reduced cell densities. Lack of competition and predation induced the recolonization by opportunistic bacteria (r-strategists), with significant increase in bacterial numbers and a low diversity (based on DGGE band pattern). All cultures stabilized after the initial recolonization phase (except Oz700) where competition due to crowding and nutrient limitation favoured bacteria with high substrate affinity (K-strategists), resulting in higher species richness and diversity (based on DGGE band pattern). The bacterial community was significantly altered qualitatively and quantitatively and may have a higher potential as invaders in the recipient depending on disinfection method and the time of release. These results have implications for the treatment strategy used for ballast water. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Proceraea exoryxae sp. nov. (Annelida, Syllidae, Autolytinae, the first known polychaete miner tunneling into the tunic of an ascidian

    Directory of Open Access Journals (Sweden)

    Daniel Martin

    2017-06-01

    Full Text Available While studying organisms living in association with the solitary tunicate Phallusia nigra (Ascidiacea, Ascidiidae from a shallow fringing reef at Zeytouna Beach (Egyptian Red Sea, one of the collected ascidians showed peculiar perforations on its tunic. Once dissected, the perforations revealed to be the openings of a network of galleries excavated in the inner tunic (atrium by at least six individuals of a polychaetous annelid. The worms belonged to the Autolytinae (Syllidae, a subfamily that is well known to include specialized predators and/or symbionts, mostly associated with cnidarians. The Red Sea worms are here described as Proceraea exoryxae sp. nov., which are anatomically distinguished by the combination of simple chaetae only in anterior chaetigers, and a unique trepan with 33 teeth in one outer ring where one large tooth alternates with one medium-sized tricuspid tooth, and one inner ring with small teeth located just behind the large teeth. Male and female epitokes were found together with atokous individuals within galleries. Proceraea exoryxae sp. nov. constitutes the first known miner in the Autolytinae and the second species in this taxon known to live symbiotically with ascidians. The implications of finding this specialized parasite are discussed considering that Phallusia nigra has been introduced worldwide, in tropical and sub-tropical ecosystems, where it has the potential of becoming invasive.

  20. Growth and phycocyanin synthesis in the heterotrophic microalga Galdieria sulphuraria on substrates made of food waste from restaurants and bakeries

    DEFF Research Database (Denmark)

    Sloth, Jenni K; Jensen, Henriette Casper; Pleissner, Daniel

    2017-01-01

    Galdieria sulphuraria 074G (Rhodophyta) was grown heterotrophically in defined medium and on amylolytic and proteolytic hydrolysed food waste from restaurants and bakeries. Substrate uptake, growth, and phycocyanin content were quantified in the cultures. The alga utilised carbohydrates and amino...... in quantities resulting in glucose concentrations of 10 and 50 g L−1 for bakery and restaurant waste, respectively. Still, G. sulphuraria 074G grew and produced phycocyanin efficiently on food waste under adequate conditions and may potentially be utilised for synthesise of high-valuable products from food...

  1. Predicting the Dispersal Potential of an Invasive Polychaete Pest along a Complex Coastal Biome.

    Science.gov (United States)

    David, Andrew A; Matthee, Conrad A; Loveday, Benjamin R; Simon, Carol A

    2016-10-01

    Boccardia proboscidea is a recently introduced polychaete in South Africa where it is a notorious pest of commercially reared abalone. Populations were originally restricted to abalone farms but a recent exodus into the wild at some localities has raised conservation concerns due to the species' invasive status in other parts of the world. Here, we assessed the dispersal potential of B. proboscidea by using a population genetic and oceanographic modeling approach. Since the worm is in its incipient stages of a potential invasion, we used the closely related Polydora hoplura as a proxy due its similar reproductive strategy and its status as a pest of commercially reared oysters in the country. Populations of P. hoplura were sampled from seven different localities and a section of the mtDNA gene, Cyt b and the intron ATPSa was amplified. A high resolution model of the coastal waters around southern Africa was constructed using the Regional Ocean Modeling System. Larvae were represented by passive drifters that were deployed at specific points along the coast and dispersal was quantified after a 12-month integration period. Our results showed discordance between the genetic and modeling data. There was low genetic structure (Φ = 0.04 for both markers) and no geographic patterning of mtDNA and nDNA haplotypes. However, the dispersal model found limited connectivity around Cape Point-a major phylogeographic barrier on the southern African coast. This discordance was attributed to anthropogenic movement of larvae and adult worms due to vectors such as aquaculture and shipping. As such, we hypothesized that cryptic dispersal could be overestimating genetic connectivity. Though wild populations of B. proboscidea could become isolated due to the Cape Point barrier, anthropogenic movement may play the critical role in facilitating the dispersal and spread of this species on the southern African coast. © The Author 2016. Published by Oxford University Press on behalf of the

  2. Population subdivision of hydrothermal vent polychaete Alvinella pompejana across equatorial and Easter Microplate boundaries.

    Science.gov (United States)

    Jang, Sook-Jin; Park, Eunji; Lee, Won-Kyung; Johnson, Shannon B; Vrijenhoek, Robert C; Won, Yong-Jin

    2016-10-28

    The Equator and Easter Microplate regions of the eastern Pacific Ocean exhibit geomorphological and hydrological features that create barriers to dispersal for a number of animals associated with deep-sea hydrothermal vent habitats. This study examined effects of these boundaries on geographical subdivision of the vent polychaete Alvinella pompejana. DNA sequences from one mitochondrial and eleven nuclear genes were examined in samples collected from ten vent localities that comprise the species' known range from 23°N latitude on the East Pacific Rise to 38°S latitude on the Pacific Antarctic Ridge. Multi-locus genotypes inferred from these sequences clustered the individual worms into three metapopulation segments - the northern East Pacific Rise (NEPR), southern East Pacific Rise (SEPR), and northeastern Pacific Antarctic Ridge (PAR) - separated by the Equator and Easter Microplate boundaries. Genetic diversity estimators were negatively correlated with tectonic spreading rates. Application of the isolation-with-migration (IMa2) model provided information about divergence times and demographic parameters. The PAR and NEPR metapopulation segments were estimated to have split roughly 4.20 million years ago (Mya) (2.42-33.42 Mya, 95 % highest posterior density, (HPD)), followed by splitting of the SEPR and NEPR segments about 0.79 Mya (0.07-6.67 Mya, 95 % HPD). Estimates of gene flow between the neighboring regions were mostly low (2 Nm  SEPR > PAR. Highly effective dispersal capabilities allow A. pompejana to overcome the temporal instability and intermittent distribution of active hydrothermal vents in the eastern Pacific Ocean. Consequently, the species exhibits very high levels of genetic diversity compared with many co-distributed vent annelids and mollusks. Nonetheless, its levels of genetic diversity in partially isolated populations are inversely correlated with tectonic spreading rates. As for many other vent taxa, this pioneering colonizer is

  3. Effect of sodium accumulation on heterotrophic growth and polyhydroxybutyrate (PHB) production by Cupriavidus necator.

    Science.gov (United States)

    Mozumder, Md Salatul Islam; Garcia-Gonzalez, Linsey; De Wever, Heleen; Volcke, Eveline I P

    2015-09-01

    This study evaluates the effect of sodium (Na(+)) concentration on the growth and PHB production by Cupriavidus necator. Both biomass growth and PHB production were inhibited by Na(+): biomass growth became zero at 8.9 g/L Na(+) concentration while PHB production was completely stopped at 10.5 g/L Na(+). A mathematical model for pure culture heterotrophic PHB production was set up to describe the Na(+) inhibition effect. The parameters related to Na(+) inhibition were estimated based on shake flask experiments. The accumulated Na(+) showed non-linear inhibition effect on biomass growth but linear inhibition effect on PHB production kinetics. Fed-batch experiments revealed that a high accumulation of Na(+) due to a prolonged growth phase, using NaOH for pH control, decreased the subsequent PHB production. The model was validated based on independent experimental data sets, showing a good agreement between experimental data and simulation results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Diffuse urban pollution increases metal tolerance of natural heterotrophic biofilms

    International Nuclear Information System (INIS)

    Fechner, Lise C.; Gourlay-Francé, Catherine; Bourgeault, Adeline; Tusseau-Vuillemin, Marie-Hélène

    2012-01-01

    This study is a first attempt to investigate the impact of urban contamination on metal tolerance of heterotrophic river biofilms using a short-term test based on β-glucosidase activity. Tolerance levels to Cu, Cd, Zn, Ni and Pb were evaluated for biofilms collected at three sites along an urban gradient in the Seine river (France). Metallic pollution increased along the river, but concentrations remained low compared to environmental quality standards. Biofilm metal tolerance increased downstream from the urban area. Multivariate analysis confirmed the correlation between tolerance and contamination and between multi-metallic and physico-chemical gradients. Therefore, tolerance levels have to be interpreted in relation to the whole chemical and physical characteristics and not solely metal exposure. We conclude that community tolerance is a sensitive biological response to urban pressure and that mixtures of contaminants at levels lower than quality standards might have a significant impact on periphytic communities. - Highlights: ► A new short-term test based on β-glucosidase activity to assess biofilm metal tolerance. ► Cd, Cu, Ni, Pb and Zn tolerance of natural biofilms collected along an urban gradient. ► Metal tolerance levels increase upstream to downstream the river. ► Community tolerance increases at environmental quality standard exposure concentrations. ► Biofilm tolerance is a sensitive biological response to diffuse urban pollution. - Metal concentrations below environmental quality standards increase tolerance levels of natural, hetetrophic biofilms downstream from an urban area.

  5. Global abundance of planktonic heterotrophic protists in the deep ocean

    Science.gov (United States)

    Pernice, Massimo C; Forn, Irene; Gomes, Ana; Lara, Elena; Alonso-Sáez, Laura; Arrieta, Jesus M; del Carmen Garcia, Francisca; Hernando-Morales, Victor; MacKenzie, Roy; Mestre, Mireia; Sintes, Eva; Teira, Eva; Valencia, Joaquin; Varela, Marta M; Vaqué, Dolors; Duarte, Carlos M; Gasol, Josep M; Massana, Ramon

    2015-01-01

    The dark ocean is one of the largest biomes on Earth, with critical roles in organic matter remineralization and global carbon sequestration. Despite its recognized importance, little is known about some key microbial players, such as the community of heterotrophic protists (HP), which are likely the main consumers of prokaryotic biomass. To investigate this microbial component at a global scale, we determined their abundance and biomass in deepwater column samples from the Malaspina 2010 circumnavigation using a combination of epifluorescence microscopy and flow cytometry. HP were ubiquitously found at all depths investigated down to 4000 m. HP abundances decreased with depth, from an average of 72±19 cells ml−1 in mesopelagic waters down to 11±1 cells ml−1 in bathypelagic waters, whereas their total biomass decreased from 280±46 to 50±14 pg C ml−1. The parameters that better explained the variance of HP abundance were depth and prokaryote abundance, and to lesser extent oxygen concentration. The generally good correlation with prokaryotic abundance suggested active grazing of HP on prokaryotes. On a finer scale, the prokaryote:HP abundance ratio varied at a regional scale, and sites with the highest ratios exhibited a larger contribution of fungi molecular signal. Our study is a step forward towards determining the relationship between HP and their environment, unveiling their importance as players in the dark ocean's microbial food web. PMID:25290506

  6. Factors affecting the bacterial community composition and heterotrophic production of Columbia River estuarine turbidity maxima.

    Science.gov (United States)

    Herfort, Lydie; Crump, Byron C; Fortunato, Caroline S; McCue, Lee Ann; Campbell, Victoria; Simon, Holly M; Baptista, António M; Zuber, Peter

    2017-12-01

    Estuarine turbidity maxima (ETM) function as hotspots of microbial activity and diversity in estuaries, yet, little is known about the temporal and spatial variability in ETM bacterial community composition. To determine which environmental factors affect ETM bacterial populations in the Columbia River estuary, we analyzed ETM bacterial community composition (Sanger sequencing and amplicon pyrosequencing of 16S rRNA gene) and bulk heterotrophic production ( 3 H-leucine incorporation rates). We collected water 20 times to cover five ETM events and obtained 42 samples characterized by different salinities, turbidities, seasons, coastal regimes (upwelling vs. downwelling), locations, and particle size. Spring and summer populations were distinct. All May samples had similar bacterial community composition despite having different salinities (1-24 PSU), but summer non-ETM bacteria separated into marine, freshwater, and brackish assemblages. Summer ETM bacterial communities varied depending on coastal upwelling or downwelling conditions and on the sampling site location with respect to tidal intrusion during the previous neap tide. In contrast to ETM, whole (>0.2 μm) and free-living (0.2-3 μm) assemblages of non-ETM waters were similar to each other, indicating that particle-attached (>3 μm) non-ETM bacteria do not develop a distinct community. Brackish water type (ETM or non-ETM) is thus a major factor affecting particle-attached bacterial communities. Heterotrophic production was higher in particle-attached than free-living fractions in all brackish waters collected throughout the water column during the rise to decline of turbidity through an ETM event (i.e., ETM-impacted waters). However, free-living communities showed higher productivity prior to or after an ETM event (i.e., non-ETM-impacted waters). This study has thus found that Columbia River ETM bacterial communities vary based on seasons, salinity, sampling location, and particle size, with the

  7. Polyphasic approach to characterize heterotrophic bacteria of biofilms and patina on walls of the Suburban Bath of the Herculaneum's archaeological excavations in Italy

    Science.gov (United States)

    Ventorino, V.; Pepe, O.; Sannino, L.; Blaiotta, G.; Palomba, S.

    2012-04-01

    Built between the walls of Herculaneum excavations, one of the world's most important archaeological sites, and the sea in the early 1st cent. AD, the Suburban Bath is one of the best thermal complexes better preserved in ancient times. The entrance opens onto a large courtyard that leads into a hallway well lit by a skylight, impluvium, with a portrait of "Apollo". From this room you can access various parts of the thermae, all beautifully preserved. A single room, mostly occupied by the pool, serving both apodyterium (dressing room) that frigidarium. Among tepidarium and frigidarium there's a room elegantly decorated with stucco and marble. The vestibule opens to the right, through a corridor, onto a waiting room with a floor in signinum opus and into a praefurnium (oven for heating). A large pool of tepidarium, connected with laconicum, a small circular room for the baths sweat, is also present. The calidarium, as usual, has a small tank for hot water and a basin for washing in cold water. Behind the calidarium is the praefurnium, an environment with the boiler for heating the bath. Although the suburban baths are well preserved, unfortunately in you can observe the development of visible microbial coatings. During the biodeterioration process, secondary colonization of wall is due to heterotrophic bacteria and fungi that induce deterioration cause structural as well as aesthetic damage such as the discoloration of materials, the formation of crusts on surfaces and the loss of material. This investigation was carried out sampling the surfaces of walls of different rooms in the Suburban Thermae according to Italian legal procedures. Depending on the samples typology, sampling was carry out using sterile nitrocellulose membranes pressed on the surface of the walls, sterile swabs or with sterile tweezers by tearing out surface material. The samples were suspended in physiological solution and immediately refrigerated until analysis. Isolated colonies grown on PCA

  8. Characterization of the heterotrophic biomass and the endogenous residue of activated sludge.

    Science.gov (United States)

    Ramdani, Abdellah; Dold, Peter; Gadbois, Alain; Déléris, Stéphane; Houweling, Dwight; Comeau, Yves

    2012-03-01

    The activated sludge process generates an endogenous residue (X(E)) as a result of heterotrophic biomass decay (X(H)). A literature review yielded limited information on the differences between X(E) and X(H) in terms of chemical composition and content of extracellular polymeric substances (EPS). The objective of this project was to characterize the chemical composition (x, y, z, a, b and c in C(x)H(y)O(z)N(a)P(b)S(c)) of the endogenous and the active fractions and EPS of activated sludge from well designed experiments. To isolate X(H) and X(E) in this study, activated sludge was generated in a 200L pilot-scale aerobic membrane bioreactor (MBR) fed with a soluble and completely biodegradable synthetic influent of sodium acetate as the sole carbon source. This influent, which contained no influent unbiodegradable organic or inorganic particulate matter, allowed the generation of a sludge composed essentially of two fractions: heterotrophic biomass X(H) and an endogenous residue X(E), the nitrifying biomass being negligible. The endogenous decay rate and the active biomass fraction of the MBR sludge were determined in 21-day aerobic digestion batch tests by monitoring the VSS and OUR responses. Fractions of X(H) and X(E) were respectively 68% and 32% in run 1 (MBR at 5.2 day SRT) and 59% and 41% in run 2 (MBR at 10.4 day SRT). The endogenous residue was isolated by subjecting the MBR sludge to prolonged aerobic batch digestion for 3 weeks, and was characterized in terms of (a) elemental analysis for carbon, nitrogen, phosphorus and sulphur; and (b) content of EPS. The MBR sludge was characterized using the same procedures (a and b). Knowing the proportions of X(H) and X(E) in this sludge, it was possible to characterize X(H) by back calculation. Results from this investigation showed that the endogenous residue had a chemical composition different from that of the active biomass with a lower content of inorganic matter (1:4.2), of nitrogen (1:2.9), of phosphorus (1

  9. Effect of heterotrophic versus autotrophic food on feeding and reproduction of the calanoid copepod Acartia tonsa : relationship with prey fatty acid composition

    DEFF Research Database (Denmark)

    Broglio, E.; Jonasdottir, Sigrun; Calbet, A.

    2003-01-01

    Gymnodinium sanguineum. The diets were also analyzed for fatty acid contents and composition, relationships with EPE and reproductive success were determined. Clear differences were found in the fatty acid contents and the composition of the different diets offered, but these differences did not correspond...... with variability in EPE. However, egg viability was correlated with ingestion of certain prey essential fatty acids; interestingly, our data do not show that ciliates and heterotrophic dinoflagellates are nutritionally superior prey for marine copepods, contrary to general expectations....

  10. The development of the larval nervous system, musculature and ciliary bands of Pomatoceros lamarckii (Annelida: heterochrony in polychaetes

    Directory of Open Access Journals (Sweden)

    Shimeld Sebastian M

    2006-10-01

    Full Text Available Abstract Background To understand the evolution of animals it is essential to have taxon sampling across a representative spread of the animal kingdom. With the recent rearrangement of most of the Bilateria into three major clades (Ecdysozoa, Lophotrochozoa and Deuterostomia it has become clear that the Lophotrochozoa are relatively poorly represented in our knowledge of animal development, compared to the Ecdysozoa and Deuterostomia. We aim to contribute towards redressing this balance with data on the development of the muscular, nervous and ciliary systems of the annelid Pomatoceros lamarckii (Serpulidae. We compare our data with other lophotrochozoans. Results P. lamarckii develops locomotory and feeding structures that enable it to become a swimming, planktotrophic larva within 24 hours. Formation of the trochophore includes development of a prototroch, metatroch and neurotroch, development of apical and posterior nervous elements at similar times, and development of musculature around the ciliary bands and digestive tract prior to development of any body wall muscles. The adult nervous and muscular systems are essentially preformed in the late larva. Interestingly, the muscular systems of the larvae and juvenile worms do not include the circular muscles of the body wall, which are considered to be plesiomorphic for annelids, although the possibility that circular muscles develop after these stages cannot be ruled out at this point. Conclusion A comparison between polychaetes shows variability in the timing (heterochrony of development of body wall muscles and elements of the nervous system. These heterochronies are one route for evolution of different life history strategies, such as adaptations to feeding requirements.

  11. A New Heterotrophic Strain for Bioleaching of Low Grade Complex Copper Ore

    Directory of Open Access Journals (Sweden)

    Kaijian Hu

    2016-02-01

    Full Text Available A new heterotrophic strain, named Providencia sp. JAT-1, was isolated and used in bioleaching of low-grade complex copper ore. The strain uses sodium citrate as a carbon source and urea as a nitrogen source to produce ammonia. The optimal growth condition of the strain is 30 C, initial pH 8, sodium citrate 10 g/L and urea 20 g/L, under which the cell density and ammonia concentration in the medium reached a maximum of 4.83 × 108 cells/mL and 14 g/L, respectively. Ammonia produced by the strain is used as the main lixiviant in bioleaching. Bioleaching results revealed that higher strain growth led to a higher copper recovery, while higher pulp density will cause a greater inhibitory effect on strain growth and ammonia production. The copper extraction reached the highest value of 54.5% at the pulp density of 1%. Malachite, chrysocolla and chalcocite are easy to leach out in this bioleaching system while chalcopyrite is difficult. Results of comparative leaching experiments show that bioleaching using JAT-1 is superior to ammonia leaching at the same condition. The metabolites produced by the strain other than ammonia are also involved in bioleaching.

  12. Antimicrobial polyketide furanoterpenoids from seaweed-associated heterotrophic bacterium Bacillus subtilis MTCC 10403.

    Science.gov (United States)

    Chakraborty, Kajal; Thilakan, Bini; Raola, Vamshi Krishna

    2017-10-01

    Brown seaweed Anthophycus longifolius (Turner) Kützing (family Sargassaceae) associated heterotrophic bacterium Bacillus subtilis MTCC 10403 was found to be a potent isolate with broad range of antibacterial activity against important perceptive food pathogens Vibrio parahaemolyticus, V. vulnificus, and Aeromonas hydrophila. This bacterium was positive for polyketide synthetase gene (KC589397), and therefore, was selected to bioprospect specialized metabolites bearing polyketide backbone. Bioactivity-guided chromatographic fractionation of the ethyl acetate extract of the seaweed-associated bacterium segregated four homologous polyketide furanoterpenoids with potential antibacterial activities against clinically important pathogens. The minimum inhibitory concentration (MIC) assay showed that the referral antibiotics tetracycline and ampicillin were active at 25 μg/mL against the test pathogens, whereas the previously undescribed (4E)-methyl 13-((16-(furan-2-yl) ethyl)-octahydro-7-hydroxy-4-((E)-23-methylbut-21-enyl)-2H-chromen-6-yl)-4-methylpent-4-enoate (compound 1) and methyl 3-(hexahydro-9-((E)-3-methylpent-1-enyl)-4H-furo[3,2-g]isochromen-6-yl) propanoate (compound 3) displayed antibacterial activities against the test pathogens at a lesser concentration (MIC subtilis MTCC 10403 demonstrated to represent a potential source of antimicrobial polyketides for pharmaceutical applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Comparison of mixotrophic to cyclic autotrophic/heterotrophic growth strategies to optimize productivity of Chlorella sorokiniana

    DEFF Research Database (Denmark)

    van Wagenen, Jonathan Myerson; De Francisci, Davide; Angelidaki, Irini

    2015-01-01

    In addition to providing cheap or free mineral nutrients, wastewaters may contain organic carbon compounds that could increase productivity of algal cultures. This study defined a strategy for the addition of organic carbon to photobioreactors in order to improve their productivity compared...... for acetate addition. Acetate was added during the light period for the mixotrophic strategy and during the dark one for the cyclic autotrophic/heterotrophic strategy. Autotrophic productivity of up to 0.99 g L−1 day−1 was obtained using the optimal tested dilution rate of 0.031 h−1. The highest mixotrophic...... productivity was 1.04 g L−1 day−1. When a constant dilution rate was applied throughout the day, cyclic heterotrophy/autotrophy (1.2 g L−1 day−1) showed higher productivity than during mixotrophic growth, while using only half as much acetate. By diluting and adding acetate only during the eight dark hours...

  14. Heterotrophic respiration in drained tropical peat is greatly affected by temperature—a passive ecosystem cooling experiment

    International Nuclear Information System (INIS)

    Jauhiainen, Jyrki; Kerojoki, Otto; Vasander, Harri; Silvennoinen, Hanna; Limin, Suwido

    2014-01-01

    Vast areas of deforested tropical peatlands do not receive noteworthy shading by vegetation, which increases the amount of solar radiation reaching the peat surface. Peat temperature dynamics and heterotrophic carbon dioxide (CO 2 ), nitrous oxide (N 2 O) and methane (CH 4 ) fluxes were monitored under four shading conditions, i.e. unshaded, 28%, 51% and 90% shading at experiment sites established on reclaimed fallow agricultural- and degraded sites in Central Kalimantan, Indonesia. Groundwater tables on the sites were at about 50 cm depth, the sites were maintained vegetation free and root ingrowth to gas flux monitoring locations was prevented. Half of the four shading areas received NPK-fertilization 50 kg ha −1 for each of N, P and K during the experiment and the other half was unfertilized. Increases in shading created a lasting decrease in peat temperatures, and decreased diurnal temperature fluctuations, in comparison to less shaded plots. The largest peat temperature difference in the topmost 50 cm peat profile was between the unshaded and 90% shaded surface, where the average temperatures at 5 cm depth differed up to 3.7 °C, and diurnal temperatures at 5 cm depth varied up to 4.2 °C in the unshaded and 0.4 °C in the 90% shaded conditions. Highest impacts on the heterotrophic CO 2 fluxes caused by the treatments were on agricultural land, where 90% shading from the full exposure resulted in a 33% lower CO 2 emission average on the unfertilized plots and a 66% lower emission average on the fertilized plots. Correlation between peat temperature and CO 2 flux suggested an approximately 8% (unfertilized) and 25% (fertilized) emissions change for each 1 °C temperature change at 5 cm depth on the agricultural land. CO 2 flux responses to the treatments remained low on degraded peatland. Fertilized conditions negatively correlated with N 2 O efflux with increases in temperature, suggesting a 12–36% lower efflux for each 1 °C increase in peat temperature

  15. Aerobic and heterotrophic nitrogen removal by Enterobacter cloacae CF-S27 with efficient utilization of hydroxylamine.

    Science.gov (United States)

    Padhi, Soumesh Kumar; Tripathy, Swetaleena; Mohanty, Sriprakash; Maiti, Nikhil Kumar

    2017-05-01

    Heterotrophic bacterium, Enterobacter cloacae CF-S27 exhibited simultaneous nitrification and aerobic denitrification in presence of high concentration of hydroxylamine. With the initial nitrogen concentration of 100mgL -1 h -1 , ammonium, nitrate and nitrite removal efficiencies were 81%, 99.9% and 92.8%, while the corresponding maximum removal rates reached as high as 11.6, 15.1 and 11.2mgL -1 h -1 respectively. Quantitative amplification by real time PCR and enzyme assay demonstrated that hydroxylamine reductase gene (hao) is actively involved in hetrotrophic nitrification and aerobic denitrification process of Enterobacter cloacae CF-S27. PCR primers were designed targeting amplification of hao gene from diversified environmental soil DNA. The strain Enterobacter cloacae CF-S27 significantly maintained the undetectable amount of dissolved nitrogen throughout 60days of zero water exchange fish culture experiment in domestic wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The Role of Heterotrophic Microbial Communities in Estuarine C Budgets and the Biogeochemical C Cycle with Implications for Global Warming: Research Opportunities and Challenges.

    Science.gov (United States)

    Anderson, O Roger

    2016-05-01

    Estuaries are among the most productive and economically important marine ecosystems at the land-ocean interface and contribute significantly to exchange of CO2 with the atmosphere. Estuarine microbial communities are major links in the biogeochemical C cycle and flow of C in food webs from primary producers to higher consumers. Considerable attention has been given to bacteria and autotrophic eukaryotes in estuarine ecosystems, but less research has been devoted to the role of heterotrophic eukaryotic microbes. Current research is reviewed here on the role of heterotrophic eukaryotic microbes in C biogeochemistry and ecology of estuaries, with particular attention to C budgets, trophodynamics, and the metabolic fate of C in microbial communities. Some attention is given to the importance of these processes in climate change and global warming, especially in relation to sources and sinks of atmospheric CO2 , while also documenting the current paucity of research on the role of eukaryotic microbes that contribute to this larger question of C biogeochemistry and the environment. Some recommendations are made for future directions of research and opportunities of applying newer technologies and analytical approaches to a more refined analysis of the role of C in estuarine microbial community processes and the biogeochemical C cycle. © 2015 The Author Journal of Eukaryotic Microbiology © 2015 International Society of Protistologists.

  17. Energetics of the Ventilatory Piston Pump of the Lugworm, a Deposit-feeding Polychaete Living in a Burrow.

    Science.gov (United States)

    Toulmond, A; Dejours, P

    1994-04-01

    The aim of this study was to tentatively estimate the energy cost of breathing in the lugworm, Arenicola marina (L.), a gallery-dwelling, piston-pump breather that moves water in a tail-to-head direction. Each tested lugworm was placed in a horizontal glass tube. The caudal end of the tube was connected to a well-aerated seawater reservoir at 20{deg}C, and the cephalic end attached to a drop meter through a tube resistance. At the exit of the cephalic chamber the O2 tension was recorded via an in situ O2 electrode, and the hydrostatic pressure of the exhaled water was also recorded. Water flow rate, total O2 uptake rate {Mdot}TOTO2, O2 extraction coefficient, and the mechanical power necessary to pump water through the resistive anterior exit of the apparatus ({Wdot}MEC), were computed. The basal metabolic rate of each animal ({Mdot}CONFO2) was separately estimated by the confinement method. {Mdot}CONFO2 subtracted from {Mdot}TOTO2 approximates {Mdot}CBO2, the O2 uptake rate necessary to activate the piston-pump breathing mechanism and to ensure the corresponding mechanical work rate, {Wdot}MEC. The results show that the energy cost of breathing, {Mdot}CBO2, of the piston-pump-breathing Arenicola is very high, with mean values approximating 47% of the {Mdot}TOTO2 value; that the mechanical power we measured, {Wdot}MEC, is very low; and that the mechanical-to-metabolic efficiency, the ratio {Wdot}MEC/{Mdot}CBO2, does not exceed 1%. These observations are compared to those obtained in other piston-pump breathers, such as Chaetopterus variopedatus and Urechis caupo, and in ciliary filter feeders including polychaetes, bivalves, and ascidians.

  18. Influence of reactive sulfide (AVS) and supplementary food on Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata

    Science.gov (United States)

    Lee, J.-S.; Lee, B.-G.; Yoo, H.; Koh, C.-H.; Luoma, S.N.

    2001-01-01

    A laboratory bioassay determined the relative contribution of various pathways of Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata exposed to moderately contaminated sediments. Juvenile worms were exposed for 25 d to experimental sediments containing 5 different reactive sulfide (acid volatile sulfides, AVS) concentrations (1 to 30 ??mol g-1), but with constant Ag, Cd, and Zn concentrations of 0.1, 0.1 and 7 ??mol g-1, respectively. The sediments were supplemented with contaminated food (TetraMin??) containing 3 levels of Ag-Cd-Zn (uncontaminated, 1?? or 5??1 metal concentrations in the contaminated sediment). The results suggest that bioaccumulation of Ag, Cd and Zn in the worms occurred predominantly from ingestion of contaminated sediments and contaminated supplementary food. AVS or dissolved metals (in porewater and overlying water) had a minor effect on bioaccumulation of the 3 metals in most of the treatments. The contribution to uptake from the dissolved source was most important in the most oxic sediments, with maximum contributions of 8% for Ag, 30% for Cd and 20% for Zn bioaccumulation. Sediment bioassays where uncontaminated supplemental food is added could seriously underestimate metal exposures in an equilibrated system; N. arenaceodentata feeding on uncontaminated food would be exposed to 40-60% less metal than if the food source was equilibrated (as occurs in nature). Overall, the results show that pathways of metal exposure are dynamically linked in contaminated sediments and shift as external geochemical characteristics and internal biological attributes vary.

  19. Distribution and enzymatic activity of heterotrophic bacteria decomposing selected macromolecular compounds in a Baltic Sea sandy beach

    Science.gov (United States)

    Podgórska, B.; Mudryk, Z. J.

    2003-03-01

    The potential capability to decompose macromolecular compounds, and the level of extracellular enzyme activities were determined in heterotrophic bacteria isolated from a sandy beach in Sopot on the Southern Baltic Sea coast. Individual isolates were capable of hydrolysing a wide spectrum of organic macromolecular compounds. Lipids, gelatine, and DNA were hydrolyzed most efficiently. Only a very small percentage of strains were able to decompose cellulose, and no pectinolytic bacteria were found. Except for starch-hydrolysis, no significant differences in the intensity of organic compound decomposition were recorded between horizontal and vertical profiles of the studied beach. Of all the studied extracellular enzymes, alkaline phosphatase, esterase lipase, and leucine acrylaminidase were most active; in contrast, the activity α-fucosidase, α-galactosidase and β-glucouronidase was the weakest. The level of extracellular enzyme activity was similar in both sand layers.

  20. Toxicological benchmarks for potential contaminants of concern for effects on soil and litter invertebrates and heterotrophic process

    Energy Technology Data Exchange (ETDEWEB)

    Will, M.E.; Suter, G.W. II

    1995-09-01

    An important step in ecological risk assessments is screening the chemicals occur-ring on a site for contaminants of potential concern. Screening may be accomplished by comparing reported ambient concentrations to a set of toxicological benchmarks. Multiple endpoints for assessing risks posed by soil-borne contaminants to organisms directly impacted by them have been established. This report presents benchmarks for soil invertebrates and microbial processes and addresses only chemicals found at United States Department of Energy (DOE) sites. No benchmarks for pesticides are presented. After discussing methods, this report presents the results of the literature review and benchmark derivation for toxicity to earthworms (Sect. 3), heterotrophic microbes and their processes (Sect. 4), and other invertebrates (Sect. 5). The final sections compare the benchmarks to other criteria and background and draw conclusions concerning the utility of the benchmarks.

  1. First record of the polychaete Ficopomatus uschakovi (Pillai, 1960 (Annelida, Serpulidae in the Colombian Caribbean, South America

    Directory of Open Access Journals (Sweden)

    Catalina Arteaga-Florez

    2014-01-01

    Full Text Available The genus Ficopomatus (Serpulidae consists of sessile, tubicolous polychaete annelid worms that may colonize a diversity of substrata, and tolerate considerable variations in salinity. Thus, members of this genus, including Ficopomatus uschakovi, in some cases are exotic and maybe invasive. The purpose of our research was to collect and identify marine organisms associated with the submerged roots of mangrove trees in the Gulf of Urabá, Colombian Caribbean, South America. Within the Gulf, there is a well-developed forest of the Red Mangrove, Rhizophora mangle, along the margins of El Uno Bay. We sampled the roots of R. mangle from five stations of the bay, and we identified specimens of F. uschakovi from each of those stations. Ficopomatus uschakovi was found to be more abundant in regions of the bay that exhibit the lowest salinity. Based on a morphological comparison of the present specimens with the original species description, revised descriptions, and other records from the Indo-West Pacific, Mexican Pacific, and Venezuelan and Brazilian Caribbean, we suggest that F. uschakovi has a broader geographical distribution. Furthermore, because of this broad distribution, and the observed tolerance for low salinity in our study, we also suggest that F. uschakovi is a euryhaline species. It is also likely that F. uschakovi will be found in other localities in the Gulf of Urabá, and in other regions of the Colombian Caribbean. Thus, this record extends the distribution of the species to the Colombian Caribbean, giving the species a continuous distribution across the northern coast of South America.

  2. Involvement of a novel p38 mitogen-activated protein kinase in larval metamorphosis of the polychaete Hydroides elegans (Haswell)

    KAUST Repository

    Wang, Hao

    2010-04-19

    Hydroides elegans is a common marine fouling organism in most tropical and subtropical waters. The life cycle of H. elegans includes a planktonic larval stage in which swimming larvae normally take 5 days to attain competency to settle. Larval metamorphosis marks the beginning of its benthic life; however, the endogenous molecular mechanisms that regulate metamorphosis remain largely unknown. In this study, a PCR-based suppressive subtractive hybridization (SSH) library was constructed to screen the genes expressed in competent larvae but not in precompetent larvae. Among the transcripts isolated from the library, 21 significantly matched sequences in the GenBank. Many of these isolated transcripts have putative roles in the reactive oxygen species (ROS) signal transduction pathway or in response to ROS stress. A putative novel p38 mitogen-activated protein kinase (MAPK), which was also isolated with SSH screen, was then cloned and characterized. The MAPK inhibitors assay showed that both p38 MAPK inhibitors SB202190 and SB203580 effectively inhibited the biofilm-induced metamorphosis of H. elegans. A cell stressors assay showed that H2O2 effectively induced larval metamorphosis of H. elegans, but the inductivity of H2O2 was also inhibited by both SB inhibitors. The catalase assay showed that the catalase could effetely inhibit H. elegans larvae from responding to inductive biofilm. These results showed that the p38 MAPK-dependent pathway plays critical role in controlling larval metamorphosis of the marine polychaete H. elegans, and the reactive oxygen radicals produced by biofilm could be the cue inducing larval metamorphosis. © 2010 Wiley-Liss, Inc.

  3. 2D Gel-Based Multiplexed Proteomic Analysis during Larval Development and Metamorphosis of the Biofouling Polychaete Tubeworm Hydroides elegans

    KAUST Repository

    Zhang, Yu; Sun, Jin; Xiao, Kang; Arellano, Shawn M.; Thiyagarajan, Vengatesen; Qian, Pei Yuan

    2010-01-01

    Larval settlement and metamorphosis of a common biofouling polychaete worm, Hydroides elegans, involve remarkable structural and physiological changes during this pelagic to sessile habitat shift. The endogenous protein molecules and post-translational modifications that drive this larval transition process are not only of interest to ecologists but also to the antifouling paint industry, which aims to control the settlement of this biofouling species on man-made structures (e.g., ship hulls). On the basis of our recent proteomic studies, we hypothesize that rapid larval settlement of H. elegans could be mediated through changes in phosphorylation status of proteins rather than extensive de novo synthesis of proteins. To test this hypothesis, 2D gel-based multiplexed proteomics technology was used to monitor the changes in protein expression and phosphorylation status during larval development and metamorphosis of H. elegans. The protein expression profiles of larvae before and after they reached competency to attach and metamorphose were similar in terms of major proteins, but the percentage of phosphorylated proteins increased from 41% to 49% after competency. Notably, both the protein and phosphoprotein profiles of the metamorphosed individuals (adult) were distinctly different from that of the larvae, with only 40% of the proteins phosphorylated in the adult stage. The intensity ratio of all phosphoprotein spots to all total protein spots was also the highest in the competent larval stage. Overall, our results indicated that the level of protein phosphorylation might play a crucial role in the initiation of larval settlement and metamorphosis. © 2010 American Chemical Society.

  4. 2D Gel-Based Multiplexed Proteomic Analysis during Larval Development and Metamorphosis of the Biofouling Polychaete Tubeworm Hydroides elegans

    KAUST Repository

    Zhang, Yu

    2010-09-03

    Larval settlement and metamorphosis of a common biofouling polychaete worm, Hydroides elegans, involve remarkable structural and physiological changes during this pelagic to sessile habitat shift. The endogenous protein molecules and post-translational modifications that drive this larval transition process are not only of interest to ecologists but also to the antifouling paint industry, which aims to control the settlement of this biofouling species on man-made structures (e.g., ship hulls). On the basis of our recent proteomic studies, we hypothesize that rapid larval settlement of H. elegans could be mediated through changes in phosphorylation status of proteins rather than extensive de novo synthesis of proteins. To test this hypothesis, 2D gel-based multiplexed proteomics technology was used to monitor the changes in protein expression and phosphorylation status during larval development and metamorphosis of H. elegans. The protein expression profiles of larvae before and after they reached competency to attach and metamorphose were similar in terms of major proteins, but the percentage of phosphorylated proteins increased from 41% to 49% after competency. Notably, both the protein and phosphoprotein profiles of the metamorphosed individuals (adult) were distinctly different from that of the larvae, with only 40% of the proteins phosphorylated in the adult stage. The intensity ratio of all phosphoprotein spots to all total protein spots was also the highest in the competent larval stage. Overall, our results indicated that the level of protein phosphorylation might play a crucial role in the initiation of larval settlement and metamorphosis. © 2010 American Chemical Society.

  5. Heterotrophic monitoring at a drinking water treatment plant by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry after different drinking water treatments.

    Science.gov (United States)

    Sala-Comorera, Laura; Blanch, Anicet R; Vilaró, Carles; Galofré, Belén; García-Aljaro, Cristina

    2017-10-01

    The aim of this work was to assess the suitability of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) for routine heterotrophic monitoring in a drinking water treatment plant. Water samples were collected from raw surface water and after different treatments during two campaigns over a 1-year period. Heterotrophic bacteria were studied and isolates were identified by MALDI-TOF MS. Moreover, the diversity index and the coefficient of population similarity were also calculated using biochemical fingerprinting of the populations studied. MALDI-TOF MS enabled us to characterize and detect changes in the bacterial community composition throughout the water treatment plant. Raw water showed a large and diverse population which was slightly modified after initial treatment steps (sand filtration and ultrafiltration). Reverse osmosis had a significant impact on the microbial diversity, while the final chlorination step produced a shift in the composition of the bacterial community. Although MALDI-TOF MS could not identify all the isolates since the available MALDI-TOF MS database does not cover all the bacterial diversity in water, this technique could be used to monitor bacterial changes in drinking water treatment plants by creating a specific protein profile database for tracking purposes.

  6. Bacterivory by a Summer Assemblage of Nanoplankton in the Ross Sea, Antarctica: Mixotrophic Versus Heterotrophic Protists

    Science.gov (United States)

    Sanders, R. W.; Gast, R. J.

    2016-02-01

    Many protists traditionally described as phototrophic have recently been shown to have retained the primitive trait of phagotrophy, and thus function as mixotrophs. Mixotrophic nanoflagellates were identified in every sample examined from a summer cruise in the Ross Sea, Antarctica, where they often were more abundant than heterotrophic nanoflagellates that have previously been considered the major bacterivores in marine waters. Mixotrophs, identified by uptake of fluorescent tracers, comprised similar proportions (9-75%) of the total bacterivorous flagellates in summer as were previously determined for an earlier spring cruise in the Ross Sea. Protist diversity also was linked to functional bacterivores using a culture-independent method in which BrdU-labeled DNA of bacterial prey was incorporated into the DNA of eukaryotic grazers. Immunoprecipitation of the BrdU-labeld DNA was followed by high-throughput sequencing to identify a diverse group of bacterivores, including numerous uncultured eukaryotes. However, its utility for identification of mixotrophs was limited by the availability of sequences from known mixotrophs.

  7. Seasonal dynamics of autotrophic and heterotrophic plankton metabolism and PCO2 in a subarctic Greenland fjord

    DEFF Research Database (Denmark)

    Sejr, Mikael K.; Krause-Jensen, Dorte; Dalsgaard, Tage

    2014-01-01

    of POC. The planktonic community was net heterotrophic in the photic zone in September (NCP = −21 ± 45 mmol O2 m−2 d−1) and February (NCP = −17 mmol O2 m−2 d−1) but net autotrophic during a developing spring bloom in May (NCP = 129 ± 102 mmol O2 m−2 d−1). In September, higher temperatures, shorter day......) and in the range of open ocean values, indicating that allochtonous carbon did not stimulate CR. The in the surface water was below atmospheric levels (September average 25.0 ± 0.71 Pa, February 35.4 ± 0.40 Pa, and May 19.8 ± 1.21 Pa), rendering the ecosystem a sink of atmospheric CO2. NCP was identified...

  8. Bioleaching of Zn, Ni and Fe from contaminated sediments of water reservoir Ružín I with using heterotrophic bacterial strains

    Directory of Open Access Journals (Sweden)

    Katarína Jablonovská

    2012-12-01

    Full Text Available This study investigates the bioleaching of the zinc polluted sediment from water reservoir Ružín I using heterotrophic bacterialstrains ubiquitous in sediment environment. The effect of bacterial activity, pH, iron solubilization and precipitation and bioleachingmedium were evaluated. The pH value controls the bacterial activity during the leaching process. Addition of glucose to the bioleachingmedium accelerated the bioleaching rate. The results indicates, that the leachibility of zinc depend on the geochemical formsand surface interaction between metal and sediment fraction. Sequential chemical extraction confirm, that Zn was predominantly boundto the iron-manganese oxides.

  9. Optimizing the Critical Factors for Lipid Productivity during Stress Phased Heterotrophic Microalgae Cultivation

    Energy Technology Data Exchange (ETDEWEB)

    Chiranjeevi, P.; Venkata Mohan, S., E-mail: vmohan_s@yahoo.com [Bioengineering and Environmental Sciences (BEES), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad (India); Academy of Scientific and Innovative Research (AcSIR) (India)

    2016-08-10

    Microalgae-derived biodiesel production is one of the promising and sustainable platform. The effect of selected stress factors (pH, temperature, salinity, and carbon supplementation) on microalgal lipids and carbohydrate production during heterotrophic mode of operation was studied using design of experimental (DOE) methodology (Taguchi approach) with variation at four levels (2{sup 1} × 4{sup 4}). Experiments were performed with allegorical batch experimental matrix (16 experimental trails). All the selected factors showed marked influence on the lipid production, whereas temperature and carbon concentration showed major influence on the carbohydrate synthesis. Interesting, relatively higher total lipid production (55% of DCW) was obtained from Experimental no. 6 (pH: 6; salinity: 1 g/l; temperature: 20°C; carbon concentration: 30 g/l). Relatively good neutral lipid fraction (13.6%) was observed with Experimental no. 8: pH: 6; salinity: 5 g/l; temperature: 30°C; carbon concentration: 1 g/l. Good carbohydrate synthesis (262 mg/g biomass) was observed with Experiment no. 3 (pH: 4; salinity: 2 g/l; temperature: 30°C; carbon concentration: 15 g/l). Fatty acid methyl esters (FAME) analysis the presence of higher number of saturated fatty acids (C12:0 to C24:0) in experimental setups 6 and 8, favoring the biodiesel properties.

  10. Metabolic diversity of the heterotrophic microorganisms and potential link to pollution of the Rouge River

    International Nuclear Information System (INIS)

    Tiquia, S.M.

    2010-01-01

    The heterotrophic microbial communities of the Rouge River were tracked using Biolog Ecoplates to understand the metabolic diversity at different temporal and spatial scales, and potential link to river pollution. Site less impacted by anthrophogenic sources (site 1), showed markedly lower metabolic diversity. The only substrates that were utilized in the water samples were carbohydrates. Sites more impacted by anthrophogenic sources (sites 8 and 9) showed higher metabolic diversity. Higher functional diversity was linked to the physico-chemical and biological properties of the water samples (i.e. higher concentrations of DO, DOC, chlorophyll, and bacterial density). Biolog analysis was found to be useful in differentiating metabolic diversity between microbial communities; in determining factors that most influence the separation of communities; and in identifying which substrates were most utilized by the communities. It can also be used as an effective ecological indicator of changes in river function attributable to urbanization and pollution. - BIOLOG differentiated metabolic diversity between microbial communities and can be used as ecological indicator of river function attributable to urbanization and pollution.

  11. Metabolic diversity of the heterotrophic microorganisms and potential link to pollution of the Rouge River

    Energy Technology Data Exchange (ETDEWEB)

    Tiquia, S.M., E-mail: smtiquia@umd.umich.ed [Department of Natural Sciences, University of Michigan, 115F Science Building, Dearborn, MI 48128 (United States)

    2010-05-15

    The heterotrophic microbial communities of the Rouge River were tracked using Biolog Ecoplates to understand the metabolic diversity at different temporal and spatial scales, and potential link to river pollution. Site less impacted by anthrophogenic sources (site 1), showed markedly lower metabolic diversity. The only substrates that were utilized in the water samples were carbohydrates. Sites more impacted by anthrophogenic sources (sites 8 and 9) showed higher metabolic diversity. Higher functional diversity was linked to the physico-chemical and biological properties of the water samples (i.e. higher concentrations of DO, DOC, chlorophyll, and bacterial density). Biolog analysis was found to be useful in differentiating metabolic diversity between microbial communities; in determining factors that most influence the separation of communities; and in identifying which substrates were most utilized by the communities. It can also be used as an effective ecological indicator of changes in river function attributable to urbanization and pollution. - BIOLOG differentiated metabolic diversity between microbial communities and can be used as ecological indicator of river function attributable to urbanization and pollution.

  12. Trophic transfer of trace metals: Subcellular compartmentalization in a polychaete and assimilation by a decapod crustacean

    Science.gov (United States)

    Rainbow, P.S.; Poirier, L.; Smith, B.D.; Brix, K.V.; Luoma, S.N.

    2006-01-01

    The chemical form of accumulated trace metal in prey is important in controlling the bioavailataility of dietary metal to a predator. This study investigated the trophic transfer of radiolabelled Ag, Cd and Zn from the polychaete worm Nereis diversicolor to the decapod crustacean Palaemonetes varians. We used 2 populations of worms with different proportions of accumulated metals in different subcellular fractions as prey, and loaded the worms with radiolabelled metals either from sediment or from solution. Accumulated radiolabelled metals were fractionated into 5 components : metal-rich granules (MRG), cellular debris, organelles, metallothionein-like proteins (MTLP), and other (heat-sensitive) proteins (HSP). Assimilation efficiencies (AE) of the metals by P. varians were measured from the 4 categories of prey (i.e. 2 populations, radiolabelled from sediment or solution). There were significant differences for each metal between the AEs from the different prey categories, confirming that origin of prey and route of uptake of accumulated trace metal will cause intraspecific differences in subsequent metal assimilation. Correlations were sought between AEs and selected fractions or combinations of fractions of metals in the prey-MRG, Trophically Available Metal (TAM = MTLP + HSP + organelles) and total protein (MTLP + HSP). TAM explained 28% of the variance in AEs for Ag, but no consistent relationships emerged between AEs and TAM or total protein when the metals were considered separately. AEs did, however, show significant positive regressions with both TAM and total protein when the 3 metals were considered together, explaining only about 21 % of the variance in each case. A significant negative relationship was observed between MRG and AE for all metals combined. The predator (P. varians) can assimilate dietary metal from a range of the fractions binding metals in the prey (N. diversicolor), with different assimilation efficiencies summated across these

  13. Superficial sediments and their relation to polychaete families in a subtropical embayment, Mexico

    Directory of Open Access Journals (Sweden)

    Nuria Méndez

    1998-06-01

    Full Text Available The soft bottoms in front of Mazatlan Bay and "Isla de la Piedra" Peninsula were studied to produce maps (depth, grain size and organic matter content in sediments. Sixty samples were obtained with a 30 x 30 van Veen grab (4-21 m depth and polychaetewere extracted from 21 subsamples. Grain size ranged from -1.05 phi (gravel to 3.81 phi (very fine sand, with fine sand predominating. Organic matter content in sediment was 0.91-3.06 % (most values = 1-2 %. Thirty polychaete families (905 individuals/m2 in mean were found, and Cirratulidae, Spionidae, Onuphidae, and Pilargiidae were dominant. Pearson's correlation of grain size, organic matter and depth proved significant (pSe realizó una caracterización de los fondos blandos de la bahía de Mazatlán y de la Península "Isla de la Piedra" a través de mapas de profundidad, tamaño de grano y materia orgánica en sedimentos. Se recolectaron 60 muestras entre 4 y 21 m de profundidad con una draga van Veen de 30 x 30 cm. De estas 60 muestras, se recolectó sedimento en 21 localidades para el estudio de las familias de poliquetos. El tamaño de grano de los sedimentos osciló entre 1.82 phi (arena mediana y 3.81 phi (arena muy fina, dominando la arena fina. El contenido de materia orgánica varió entre 0.91 y 3.06 %, siendo los valores comprendidos entre 1 y 2 %, los más frecuentes. En total se recolectaron 30 familias de poliquetos (905 individuos/m2 en promedio, de las cuales Cirratulidae, Spionidae, Onuphidae y Pilargiidae resultaron dominantes. Los valores de correlación de Pearson entre el tamaño de grano, la materia orgánica y la profundidad resultaron significativos (p<0.01; p<0.02, lo que confirma las relaciones observadas en los patrones de distribución a lo largo del área de estudio. El análisis de componentes principales mostró la asociación de varias familias con la profundidad (factor 1, con el tamaño de grano (factor 2 y con la materia orgánica (factor 3. Sin embargo, se

  14. Trans-generational plasticity in physiological thermal tolerance is modulated by maternal pre-reproductive environment in the polychaete Ophryotrocha labronica.

    Science.gov (United States)

    Massamba-N'Siala, Gloria; Prevedelli, Daniela; Simonini, Roberto

    2014-06-01

    Maternal temperature is known to affect many aspects of offspring phenotype, but its effect on offspring physiological thermal tolerance has received less attention, despite the importance of physiological traits in defining organismal ability to cope with temperature changes. To fill this gap, we used the marine polychaete Ophryotrocha labronica to investigate the influence of maternal temperature on offspring upper and lower thermal tolerance limits, and assess whether maternal influence changed according to the stage of offspring pre-zygotic development at which a thermal cue was provided. Measurements were taken on adult offspring acclimated to 18 or 30°C, produced by mothers previously reared at 24°C and then exposed to 18 or 30°C at an early and late stage of oogenesis. When the shift from 24°C was provided early during oogenesis, mothers produced offspring with greater cold and heat tolerance whenever mother-offspring temperatures did not match, with respect to when they matched, suggesting the presence of an anticipatory maternal effect triggered by the thermal variation. Conversely, when the cue was provided later during oogenesis, more tolerant offspring were observed when temperatures persisted across generations. In this case, maternal exposure to 18 or 30°C may have benefited offspring performance, while limitations in the transmission of the thermal cue may account for the lack of correlation between maternal experiences and offspring performance when mother-offspring environments did not match. Our results provided evidence for a trans-generational effect of temperature on physiological performance characterised by a high context dependency, and are discussed in the light of maternal pre-reproductive experiences. © 2014. Published by The Company of Biologists Ltd.

  15. Heterotrophic and mixotrophic growth of Micractinium pusillum Fresenius in the presence of acetate and glucose: effect of light and acetate gradient concentration.

    Science.gov (United States)

    Bouarab, L; Dauta, A; Loudiki, M

    2004-06-01

    The main objective of this study was to determine the importance of secondary mechanism of organic carbon utilization (mixotrophic and heterotrophic modes) in addition to CO2 fixation (photoautotrophic mode) in the green alga, Micractinium pusillum Fresenius (chlorophyta), isolated from a waste stabilization pond. The growth was studied in the presence of acetate and glucose. The incorporation rate of 14C- acetate was measured in the light and in the dark at different concentrations. Finally, in order to underline the role of photosynthesis and respiration processes in the acetate assimilation, the effect of two specific metabolic inhibitors, a specific inhibitor of photosystem II (DCMU) and an uncoupler respiratory (DNP), has been studied. The obtained results showed that M. pusillum grows in the presence of organic substrates, i.e., glucose and acetate, in the light (mixotrophic growth) as well as in the dark (Heterotrophic growth). The growth was much more important in the light than in the dark and more in the presence of glucose than of acetate. In the light, the presence of acetate led to a variation of growth parameters mumax, iotaopt, and beta. The effect of acetate gradient on the growth of the microalga was severe as soon as its concentration in the medium was higher. The acetate uptake followed a Michaelis-Menten kinetic in the light as well as in the dark. The capacity of assimilation was slightly higher in the dark. The utilization of DNP and DCMU indicates that acetate incorporation is an active process depending on both anabolic (photosynthesis) and catabolic (respiration) metabolisms, corroborating the model of the Michaelis-Menten kinetic.

  16. Enhanced heterotrophic denitrification: effect of dairy industry sludge acclimatization and operating conditions.

    Science.gov (United States)

    Akbari Shahabi, Zeinab; Naeimpoor, Fereshteh

    2014-06-01

    Heterotrophic denitrification of drinking water was enhanced by selection of an anoxic sludge taken from a dairy industry among the sludges taken from various industries, and the effect of carbon sources was examined. Acclimatization to high nitrate concentration was then carried out in a five-stage process. Considering removals of both nitrate and nitrite, the sludge taken from anoxic unit of Tehran Pegah dairy industry was shown to be the superior microbial culture, with ethanol as carbon source as compared to acetate. To enhance the rate of denitrification, acclimatization to nitrate (at 100, 200, 400, 800, and 1,600 mg N-NO3/L) was carried out in sequencing batch reactors over a 3-month period under anoxic condition, and comparisons were made between the performances of acclimated and non-acclimated sludges at each stage. It was found that acclimatization up to the fourth stage enhanced the specific denitrification rate to a high value of 29.6 mg N-NO3/h/g mixed liquor suspended solids (MLSS), with no significant nitrite accumulation. Additionally, the effect of initial pH (6, 6.5, 7, and 7.5) and carbon-to-nitrogen (C/N) ratio (1, 1.5, 2, and 3) on the performance of this final acclimated sludge was assessed, where initial pH of 7 and C/N ratio of 1.5 resulted in the best performances considering both nitrate and nitrite removal.

  17. Rapid Prediction of Bacterial Heterotrophic Fluxomics Using Machine Learning and Constraint Programming.

    Directory of Open Access Journals (Sweden)

    Stephen Gang Wu

    2016-04-01

    Full Text Available 13C metabolic flux analysis (13C-MFA has been widely used to measure in vivo enzyme reaction rates (i.e., metabolic flux in microorganisms. Mining the relationship between environmental and genetic factors and metabolic fluxes hidden in existing fluxomic data will lead to predictive models that can significantly accelerate flux quantification. In this paper, we present a web-based platform MFlux (http://mflux.org that predicts the bacterial central metabolism via machine learning, leveraging data from approximately 100 13C-MFA papers on heterotrophic bacterial metabolisms. Three machine learning methods, namely Support Vector Machine (SVM, k-Nearest Neighbors (k-NN, and Decision Tree, were employed to study the sophisticated relationship between influential factors and metabolic fluxes. We performed a grid search of the best parameter set for each algorithm and verified their performance through 10-fold cross validations. SVM yields the highest accuracy among all three algorithms. Further, we employed quadratic programming to adjust flux profiles to satisfy stoichiometric constraints. Multiple case studies have shown that MFlux can reasonably predict fluxomes as a function of bacterial species, substrate types, growth rate, oxygen conditions, and cultivation methods. Due to the interest of studying model organism under particular carbon sources, bias of fluxome in the dataset may limit the applicability of machine learning models. This problem can be resolved after more papers on 13C-MFA are published for non-model species.

  18. Survey of the marine benthic infauna collected from the United States radioactive waste disposal sites off the Farallon Islands, California. Final report

    International Nuclear Information System (INIS)

    Reish, D.J.

    1983-01-01

    Benthic biological samples were taken in 1977 from the vicinity of the Farallon Islands radioactive waste disposal sites for characterization of the infaunal macroinvertebrates and foraminifera. A total of 120 invertebrate species were collected, of which 75 species (63 percent) were polychaetes. Forty-three of these polychaete species have not previously been reported from depths greater than 1000m. A total of 1044 macroinvertebrate specimens were collected of which 54 percent were polychates. Only the nematods were present at all six benthic stations, but the community structure was dominated by the polychaetes Tauberia gracilis, Allia pulchra, Chaetozone setosa, and Cossura candida. Living and dead foraminifera were reported. The possible role of polychaetes in bioturbation and in the marine food chain is briefly discussed with respect to the various polychaete feeding mechanisms

  19. Adaptation and acclimatization to ocean acidification in marine ectotherms: an in situ transplant experiment with polychaetes at a shallow CO2 vent system.

    Science.gov (United States)

    Calosi, Piero; Rastrick, Samuel P S; Lombardi, Chiara; de Guzman, Heidi J; Davidson, Laura; Jahnke, Marlene; Giangrande, Adriana; Hardege, Jörg D; Schulze, Anja; Spicer, John I; Gambi, Maria-Cristina

    2013-01-01

    Metabolic rate determines the physiological and life-history performances of ectotherms. Thus, the extent to which such rates are sensitive and plastic to environmental perturbation is central to an organism's ability to function in a changing environment. Little is known of long-term metabolic plasticity and potential for metabolic adaptation in marine ectotherms exposed to elevated pCO2. Consequently, we carried out a series of in situ transplant experiments using a number of tolerant and sensitive polychaete species living around a natural CO2 vent system. Here, we show that a marine metazoan (i.e. Platynereis dumerilii) was able to adapt to chronic and elevated levels of pCO2. The vent population of P. dumerilii was physiologically and genetically different from nearby populations that experience low pCO2, as well as smaller in body size. By contrast, different populations of Amphiglena mediterranea showed marked physiological plasticity indicating that adaptation or acclimatization are both viable strategies for the successful colonization of elevated pCO2 environments. In addition, sensitive species showed either a reduced or increased metabolism when exposed acutely to elevated pCO2. Our findings may help explain, from a metabolic perspective, the occurrence of past mass extinction, as well as shed light on alternative pathways of resilience in species facing ongoing ocean acidification.

  20. Upper Arctic Ocean water masses harbor distinct communities of heterotrophic flagellates

    Directory of Open Access Journals (Sweden)

    A. Monier

    2013-06-01

    Full Text Available The ubiquity of heterotrophic flagellates (HFL in marine waters has been recognized for several decades, but the phylogenetic diversity of these small (ca. 0.8–20 μm cell diameter, mostly phagotrophic protists in the upper pelagic zone of the ocean is underappreciated. Community composition of microbes, including HFL, is the result of past and current environmental selection, and different taxa may be indicative of food webs that cycle carbon and energy very differently. While all oceanic water columns can be density stratified due to the temperature and salinity characteristics of different water masses, the Arctic Ocean is particularly well stratified, with nutrients often limiting in surface waters and most photosynthetic biomass confined to a subsurface chlorophyll maximum layer, where light and nutrients are both available. This physically well-characterized system provided an opportunity to explore the community diversity of HFL from different water masses within the water column. We used high-throughput DNA sequencing techniques as a rapid means of surveying the diversity of HFL communities in the southern Beaufort Sea (Canada, targeting the surface, the subsurface chlorophyll maximum layer (SCM and just below the SCM. In addition to identifying major clades and their distribution, we explored the micro-diversity within the globally significant but uncultivated clade of marine stramenopiles (MAST-1 to examine the possibility of niche differentiation within the stratified water column. Our results strongly suggested that HFL community composition was determined by water mass rather than geographical location across the Beaufort Sea. Future work should focus on the biogeochemical and ecological repercussions of different HFL communities in the face of climate-driven changes to the physical structure of the Arctic Ocean.

  1. Osmoadaptative Strategy and Its Molecular Signature in Obligately Halophilic Heterotrophic Protists.

    Science.gov (United States)

    Harding, Tommy; Brown, Matthew W; Simpson, Alastair G B; Roger, Andrew J

    2016-08-03

    Halophilic microbes living in hypersaline environments must counteract the detrimental effects of low water activity and salt interference. Some halophilic prokaryotes equilibrate their intracellular osmotic strength with the extracellular milieu by importing inorganic solutes, mainly potassium. These "salt-in" organisms characteristically have proteins that are highly enriched with acidic and hydrophilic residues. In contrast, "salt-out" halophiles accumulate large amounts of organic solutes like amino acids, sugars and polyols, and lack a strong signature of halophilicity in the amino acid composition of cytoplasmic proteins. Studies to date have examined halophilic prokaryotes, yeasts, or algae, thus virtually nothing is known about the molecular adaptations of the other eukaryotic microbes, that is, heterotrophic protists (protozoa), that also thrive in hypersaline habitats. We conducted transcriptomic investigations to unravel the molecular adaptations of two obligately halophilic protists, Halocafeteria seosinensis and Pharyngomonas kirbyi Their predicted cytoplasmic proteomes showed increased hydrophilicity compared with marine protists. Furthermore, analysis of reconstructed ancestral sequences suggested that, relative to mesophiles, proteins in halophilic protists have undergone fewer substitutions from hydrophilic to hydrophobic residues since divergence from their closest relatives. These results suggest that these halophilic protists have a higher intracellular salt content than marine protists. However, absence of the acidic signature of salt-in microbes suggests that Haloc. seosinensis and P. kirbyi utilize organic osmolytes to maintain osmotic equilibrium. We detected increased expression of enzymes involved in synthesis and transport of organic osmolytes, namely hydroxyectoine and myo-inositol, at maximal salt concentration for growth in Haloc. seosinensis, suggesting possible candidates for these inferred organic osmolytes. © The Author 2016

  2. Real-time ArcGIS and heterotrophic plate count based chloramine disinfectant control in water distribution system.

    Science.gov (United States)

    Bai, Xiaohui; Zhi, Xinghua; Zhu, Huifeng; Meng, Mingqun; Zhang, Mingde

    2015-01-01

    This study investigates the effect of chloramine residual on bacteria growth and regrowth and the relationship between heterotrophic plate counts (HPCs) and the concentration of chloramine residual in the Shanghai drinking water distribution system (DWDS). In this study, models to control HPCs in the water distribution system and consumer taps are also developed. Real-time ArcGIS was applied to show the distribution and changed results of the chloramine residual concentration in the pipe system by using these models. Residual regression analysis was used to get a reasonable range of the threshold values that allows the chloramine residual to efficiently inhibit bacteria growth in the Shanghai DWDS; the threshold values should be between 0.45 and 0.5 mg/L in pipe water and 0.2 and 0.25 mg/L in tap water. The low residual chloramine value (0.05 mg/L) of the Chinese drinking water quality standard may pose a potential health risk for microorganisms that should be improved. Disinfection by-products (DBPs) were detected, but no health risk was identified.

  3. Nitrate removal from groundwater by cooperating heterotrophic with autotrophic denitrification in a biofilm-electrode reactor.

    Science.gov (United States)

    Zhao, Yingxin; Feng, Chuanping; Wang, Qinghong; Yang, Yingnan; Zhang, Zhenya; Sugiura, Norio

    2011-09-15

    An intensified biofilm-electrode reactor (IBER) combining heterotrophic and autotrophic denitrification was developed for treatment of nitrate contaminated groundwater. The reactor was evaluated with synthetic groundwater (NO(3)(-)-N50 mg L(-1)) under different hydraulic retention times (HRTs), carbon to nitrogen ratios (C/N) and electric currents (I). The experimental results demonstrate that high nitrate and nitrite removal efficiency (100%) were achieved at C/N = 1, HRT = 8h, and I = 10 mA. C/N ratios were reduced from 1 to 0.5 and the applied electric current was changed from 10 to 100 mA, showing that the optimum running condition was C/N = 0.75 and I = 40 mA, under which over 97% of NO(3)(-)-N was removed and organic carbon (methanol) was completely consumed in treated water. Simultaneously, the denitrification mechanism in this system was analyzed through pH variation in effluent. The CO(2) produced from the anode acted as a good pH buffer, automatically controlling pH in the reaction zone. The intensified biofilm-electrode reactor developed in the study was effective for the treatment of groundwater polluted by nitrate. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Assessment of macrofauna around Tarapur Atomic Power Station (TAPS), Maharashtra, India

    International Nuclear Information System (INIS)

    Kubal, Priti; Ambekar, Ajit; Prakash, Chandra; Sawant, Paramita B.; Pal, Asim K.; Lakra, W.S.; Baburajan, A.

    2015-01-01

    A study was carried out to observe the macrofaunal habitation in the coastal area of India's first commercial atomic power station at Tarapur, Maharashtra. Mostly macrobenthos are sedentary as well as sessile in nature; therefore, they are used as indicator organism to monitor health of marine ecosystem. The faunal record observed consisted of 25 groups with 16 different polychaete families dominated by nereidae, capitellidae and spionidae. Shannon wiener index (H') was highest at Varor for faunal groups (2.07) and polychaete families (2.89) and lowest at anthropogenically stressed Uchheli (faunal group -0.77 and polychaete family 1.94). These findings were further supported by dendrogram. Margalef's species richness was highest at Varor (fauna -1.93 and polychaete family -1.61) and lowest at Nandgoan (fauna-1.00 and polychaete family - 0.74) due to dominance of environmental bioindicators, polychaete (nereidae). Along with these observations, hydro-sedimentological parameters revealed comprehensive picture of community structure of macrobenthos and polychaetes families. The elevated water temperature was noticed at TAPS 3 and 4 (30.1 °C) which is under permissible limit (26-28°C ±7) accompanied by pH (7.0). Dissolved oxygen was lowest at Uchheli (4.1mgl -1 ) and maximum was observed at TAPS 1 and 2 area (7.5mgl -1 ). (author)

  5. Understanding the life of a sandy beach polychaete of functional importance - Scolelepis squamata (Polychaeta: Spionidae) on Belgian sandy beaches (northeastern Atlantic, North Sea)

    Science.gov (United States)

    Speybroeck, Jeroen; Alsteens, Lotte; Vincx, Magda; Degraer, Steven

    2007-08-01

    The cosmopolitan sandy beach polychaete Scolelepis squamata constitutes an important food resource for juvenile flatfish and wading birds in the northeastern Atlantic, thus playing an important role in sandy beach ecosystem functioning. However, its population dynamics and life history in this part of the world have gone widely uninvestigated. Eight beach transects on Belgian sandy beaches were sampled monthly from October 2003 until October 2004, in order to investigate seasonal trends in the species' abundance, biomass, secondary production, and patterns in reproduction and zonation. Average density, modal density and modal biomass (ash-free dry weight) (mean average density = 169 ± 9 SE ind/m 2; mean modal density = 505 ± 38 SE ind/m 2; mean modal biomass = 0.25 ± 0.02 SE g/m 2) did not exhibit major seasonal changes, whereas average biomass (0.081 ± 0.005 SE g/m 2) and individuals and biomass per strip transect (IST = 16286 ± 1330 SE ind/m; BMST = 7.8 + 0.7 SE g/m) did, peaking in May 2004. Production was calculated at 1.9 g/(m 2*year) (size-frequency method, SFM) and 0.88 g/(m 2*year) (mass specific growth rate method, MSGR) and mean annual biomass was 0.797 g/m 2; resulting in a P/B ratio of 2.40/year (SFM) and 1.11/year (MSGR), which is intermediate to moderately low compared to other polychaete species. Gravid individuals were found from February until August and a single recruitment period was observed from July until September. An average sex ratio of 1.41 ± 0.08 SE was calculated, with a female predominance. Highest densities (>200 ind/m 2) were mostly found above 3 m above MLLWS and at a median grain size from 190 to 320 μm. Average modal or peak density along each transect was situated from 3.95 m up to 4.40 m above MLLWS, in contrast to some other studies where the species was restricted to mid-tidal levels. Significant differences in elevation of peak density were found between non-gravid (411 ± 4 SE cm) and gravid (402 ± 5 SE cm) animals

  6. Revealing polychaetes invasion patterns: Identification, reproduction and potential risks of the Korean ragworm, Perinereis linea (Treadwell), in the Western Mediterranean

    Science.gov (United States)

    Arias, Andrés; Richter, Alexandra; Anadón, Nuria; Glasby, Christopher J.

    2013-10-01

    An established population of the polychaetous annelid Perinereis linea (Treadwell) is reported for the first time outside its native distribution range (NW Pacific). This exotic worm has reached the Western Mediterranean (Mar Menor lagoon) via importing live fishing-bait as it is commonly used by anglers in Mar Menor lagoon, an area largely used for recreational fishing. To avoid confusion with other related species, and because the scientific name has been in synonymy for many years, P. linea is redescribed and illustrated. We focus on the reproductive biology and ecology of P. linea to help to understand its introduction, naturalization and spread along this coastal lagoon. Comparison between the Mediterranean population with a native population from South Korea revealed that the species exhibits a great reproductive plasticity and adaptability, which depends on the environmental conditions. Perinereis linea can reproduce after acquiring the epitokous form or prior to complete epitokal modification. In the Mar Menor lagoon population females release eggs asynchronically without completing epitokal modifications. However, under particular laboratory conditions females produce eggs synchronically and release them after complete epitokal transformations. Fertilization can occur internally in the female coelom, and females release zygotes and larvae through openings in their body walls; they are then incubated in gelatinous masses attached to the female parapodia. The sperm morphology is of the ent-aquasperm type. The eggs and larvae are attacked by symbiotic ciliate protozoa that feed on their yolk reserves. These foreign ciliates may act as carriers of disease in native beachworms and constitute an important risk for the ecosystem health. Finally, we provide recommendations on the prevention of the adverse effects that this exotic ragworm can cause in receiving ecosystems.

  7. Heterotrophic Growth and Production of Xanthophylls by Chlorella pyrenoidosa

    Science.gov (United States)

    Theriault, Robert J.

    1965-01-01

    The growth and level of xanthophylls of several representative species of green algae were investigated as a possible source of pigmentation for the egg yolk and broiler markets. Chlorella pyrenoidosa 7-11-05 was selected for fermentation studies because of its high level of xanthophylls and wide temperature range for growth. The heterotrophic metabolism was preferred because of the ease of adaptability to present fermentation equipment. When used as the sole carbon source, glucose was the only sugar, among many tested, that gave appreciable growth in illuminated shaken flasks. A dry cell weight of 90 g per liter and total xanthophylls of 450 mg per liter were obtained from 190 g per liter of glucose monohydrate in 168-hr illuminated shaken flasks. Higher levels of glucose decreased yields. In combination with glucose, monosaccharides, such as fructose and galactose, were readily assimilated. The 7-11-05 strain was adapted to galactose as the sole carbon source after six vegetative passages. Light of the proper intensity and duration stimulated total xanthophylls approximately 35%. The effect on dry cell weight and total xanthophylls of seven antibiotics added at various levels in shaken flasks was studied. Erythromycin was essentially stable throughout the fermentation and nontoxic up to 25 μg/ml, with only slight toxicity at higher levels. Both erythromycin and ristocetin were effective in controlling a high incidence of bacterial contamination in 30-liter fermentors. With the higher agitation and aeration rates possible in 30-liter fermentors, dry cell weights in excess of 100 g per liter and total xanthophylls of 467 to 512 mg per liter were readily obtained from 230 to 260 g per liter of glucose in 162-hr illuminated batch-type fermentations. Continuous-feed runs yielded a dry cell weight of 302 g per liter and total xanthophylls of 650 mg per liter from 520 g per liter of glucose. The type of Chlorella cell produced was an important consideration with

  8. Estimating heterotrophic respiration at large scales: Challenges, approaches, and next steps

    Science.gov (United States)

    Bond-Lamberty, Ben; Epron, Daniel; Harden, Jennifer W.; Harmon, Mark E.; Hoffman, Forrest; Kumar, Jitendra; McGuire, Anthony David; Vargas, Rodrigo

    2016-01-01

    Heterotrophic respiration (HR), the aerobic and anaerobic processes mineralizing organic matter, is a key carbon flux but one impossible to measure at scales significantly larger than small experimental plots. This impedes our ability to understand carbon and nutrient cycles, benchmark models, or reliably upscale point measurements. Given that a new generation of highly mechanistic, genomic-specific global models is not imminent, we suggest that a useful step to improve this situation would be the development of “Decomposition Functional Types” (DFTs). Analogous to plant functional types (PFTs), DFTs would abstract and capture important differences in HR metabolism and flux dynamics, allowing modelers and experimentalists to efficiently group and vary these characteristics across space and time. We argue that DFTs should be initially informed by top-down expert opinion, but ultimately developed using bottom-up, data-driven analyses, and provide specific examples of potential dependent and independent variables that could be used. We present an example clustering analysis to show how annual HR can be broken into distinct groups associated with global variability in biotic and abiotic factors, and demonstrate that these groups are distinct from (but complementary to) already-existing PFTs. A similar analysis incorporating observational data could form the basis for future DFTs. Finally, we suggest next steps and critical priorities: collection and synthesis of existing data; more in-depth analyses combining open data with rigorous testing of analytical results; using point measurements and realistic forcing variables to constrain process-based models; and planning by the global modeling community for decoupling decomposition from fixed site data. These are all critical steps to build a foundation for DFTs in global models, thus providing the ecological and climate change communities with robust, scalable estimates of HR.

  9. Algunos poliquetos holoplanctónicos (Annelida: Polychaeta del Parque Nacional Isla del Coco, Costa Rica Some holoplanktonic polychaetes (Annelida: Polychaeta from the Parque Nacional Isla del Coco, Costa Rica

    Directory of Open Access Journals (Sweden)

    Soledad Jiménez-Cueto

    2012-11-01

    Full Text Available Los poliquetos holoplanctónicos no han sido estudiados en las aguas oceánicas adyacentes al Parque Isla del Coco. Se estudiaron estas formas pelágicas a partir del análisis de muestras de zooplancton recolectadas en esta área protegida. Las muestras fueron obtenidas mediante redes de plancton estándar (0.2-0.5mm de malla, 0.49m de diámetro de boca en arrastres horizontales y verticales en la isla oceánica Isla del Coco, Costa Rica, en el Pacífico Tropical Oriental. Los poliquetos pelágicos de esta zona fueron analizados taxonómicamente. El material obtenido incluye representantes de seis especies y cinco familias: Alciopidae, Lopadorhynchidae, Tomopteridae, Polynoidae y Typhloscolecidae. Se presentan diagnosis breves, sino- nimias, análisis morfológicos comparativos, ilustraciones taxonómicas y la distribución conocida de las especies recolectadas en el plancton de Isla del Coco. El registro de Drieschia pellucida Moore es el primero en el Pacífico Tropical Oriental; nuestro espécimen muestra algunas diferencias respecto a la descripción original. El resto de las especies han sido encontradas previamente en aguas del Pacífico Tropical Oriental y en el Domo de Costa Rica, pero son los primeros registros para esta área protegida.The holoplanktonic polychaetes have not been surveyed in the oceanic waters adjacent to Isla del Coco. These pelagic forms are studied based on the analysis of zooplankton samples collected in the area. Samples were obtained both at night and daytime by standard plankton nets (0.2-0.5 mm meshes, 0.49 m mouth diameter hauled horizontally and vertically off the oceanic island Isla del Coco, Costa Rica in the Eastern Tropical Pacific. Pelagic polychaetes were collected in one of the night samples and were taxonomically analyzed. The material obtained includes representatives of six species and five families: Alciopidae, Lopadorrhynchidae, Tomopteridae, Polynoidae, and Typhloscolecidae. Brief diagnoses

  10. Production of betalaines by Myrtillocactus cell cultures. Passage from heterotrophic state to autotrophic state with Asparagus cell cultures

    Energy Technology Data Exchange (ETDEWEB)

    Bulard, C; Mary, J; Chaumont, D; Gudin, C

    1982-11-01

    Myrtillocactus tissue cultures are grown from the epicotyl of young plantlets. With an appropriate growing medium it is possible, after transfer of fragments of these cultures to a liquid environment, to obtain dissociation and proliferation of cells. The production of betalaic pigments is induced in solid surroundings by adjustement of the growing medium composition and can be maintained in a liquid environment. The multiplication of pigmented cells in suspension may thus be obtained. The conversion of Asparagus cell suspensions from the heterotrophic state (use of lactose as source of carbon) to the autotrophic state (carbon supplied by CO/sub 2/) is obtained by a gradual reduction in the sugar concentration of the medium combined with a rise in the CO/sub 2/ content of the gas mixture atmosphere injected into the cultivator. The passage to the autotrophic state of a Myrtillocactus suspension would enable the production conditions of a metabolite (Betalaine) to be studied by micro-algae culture techniques.

  11. Nitrogen Removal Characteristics of Pseudomonas putida Y-9 Capable of Heterotrophic Nitrification and Aerobic Denitrification at Low Temperature

    Directory of Open Access Journals (Sweden)

    Yi Xu

    2017-01-01

    Full Text Available The cold-adapted bacterium Pseudomonas putida Y-9 was investigated and exhibited excellent capability for nitrogen removal at 15°C. The strain capable of heterotrophic nitrification and aerobic denitrification could efficiently remove ammonium, nitrate, and nitrite at an average removal rate of 2.85 mg, 1.60 mg, and 1.83 mg NL−1 h−1, respectively. Strain Y-9 performed nitrification in preference to denitrification when ammonium and nitrate or ammonium and nitrite coexisted in the solution. Meantime, the presence of nitrate had no effect on the ammonium removal rate of strain Y-9, and yet the presence of high concentration of nitrite would inhibit the cell growth and decrease the nitrification rate. The experimental results indicate that P. putida Y-9 has potential application for the treatment of wastewater containing high concentrations of ammonium along with its oxidation products at low temperature.

  12. Influence of Asellus aquaticus on Escherichia coli, Klebsiella pneumoniae, Campylobacter jejuni and naturally occurring heterotrophic bacteria in drinking water

    DEFF Research Database (Denmark)

    Christensen, Sarah Christine; Nissen, Erling; Arvin, Erik

    2012-01-01

    . aquaticus on microbial water quality in non-chlorinated drinking water in controlled laboratory experiments. Pure cultures of the indicator organisms Escherichia coli and Klebsiella pneumoniae and the pathogen Campylobacter jejuni as well as naturally occurring heterotrophic drinking water bacteria...... decreased over time, following a first order decay with half lives of 5.3, 18.4 and 1.3 days, respectively. A. aquaticus did not affect survival of indicators and pathogens substantially whereas HPC were influenced by presence of dead A. aquaticus. Growth rates increased with an average of 48% for bacteria...... grown on R-2A agar and an average of 83% for bacteria grown on yeast extract agar when dead A. aquaticus were present compared to no and living A. aquaticus present. A. aquaticus associated E. coli, K. pneumoniae and C. jejuni were measured (up to 25 per living and 500 per dead A. aquaticus) and so were...

  13. Proteome and membrane fatty acid analyses on Oligotropha carboxidovorans OM5 grown under chemolithoautotrophic and heterotrophic conditions.

    Directory of Open Access Journals (Sweden)

    Debarati Paul

    Full Text Available Oligotropha carboxidovorans OM5 T. (DSM 1227, ATCC 49405 is a chemolithoautotrophic bacterium able to utilize CO and H(2 to derive energy for fixation of CO(2. Thus, it is capable of growth using syngas, which is a mixture of varying amounts of CO and H(2 generated by organic waste gasification. O. carboxidovorans is capable also of heterotrophic growth in standard bacteriologic media. Here we characterize how the O. carboxidovorans proteome adapts to different lifestyles of chemolithoautotrophy and heterotrophy. Fatty acid methyl ester (FAME analysis of O. carboxidovorans grown with acetate or with syngas showed that the bacterium changes membrane fatty acid composition. Quantitative shotgun proteomic analysis of O. carboxidovorans grown in the presence of acetate and syngas showed production of proteins encoded on the megaplasmid for assimilating CO and H(2 as well as proteins encoded on the chromosome that might have contributed to fatty acid and acetate metabolism. We found that adaptation to chemolithoautotrophic growth involved adaptations in cell envelope, oxidative homeostasis, and metabolic pathways such as glyoxylate shunt and amino acid/cofactor biosynthetic enzymes.

  14. Characterization of a halophilic heterotrophic nitrification-aerobic denitrification bacterium and its application on treatment of saline wastewater.

    Science.gov (United States)

    Duan, Jinming; Fang, Hongda; Su, Bing; Chen, Jinfang; Lin, Jinmei

    2015-03-01

    A novel halophilic bacterium capable of heterotrophic nitrification-aerobic denitrification was isolated from marine sediments and identified as Vibrio diabolicus SF16. It had ability to remove 91.82% of NH4(+)-N (119.77 mg/L) and 99.71% of NO3(-)-N (136.43 mg/L). The nitrogen balance showed that 35.83% of initial NH4(+)-N (119.77 mg/L) was changed to intracellular nitrogen, and 53.98% of the initial NH4(+)-N was converted to gaseous denitrification products. The existence of napA gene further proved the aerobic denitrification ability of strain SF16. The optimum culture conditions were salinity 1-5%, sodium acetate as carbon source, C/N 10, and pH 7.5-9.5. When an aerated biological filter system inoculated with strain SF16 was employed to treat saline wastewater, the average removal efficiency of NH4(+)-N and TN reached 97.14% and 73.92%, respectively, indicating great potential of strain SF16 for future full-scale applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. A decadal (2002-2014 analysis for dynamics of heterotrophic bacteria in an Antarctic coastal ecosystem: variability and physical and biogeochemical forcings

    Directory of Open Access Journals (Sweden)

    Hyewon Kim

    2016-11-01

    Full Text Available We investigated the dynamics of heterotrophic bacteria in the coastal western Antarctic Peninsula (WAP, using decadal (2002-2014 time series of two bacterial variables, bacterial production (BP via 3H-leucine incorporation rates and bacterial biomass (BB via bacterial abundance, collected at Palmer Antarctica Long Term Ecological Research (LTER Station B (64.8°S, 64.1°W over a full austral growing season (October-March. Strong seasonal and interannual variability in the degree of bacterial coupling with phytoplankton processes were observed with varying lags. On average, BP was only 4% of primary production (PP, consistent with low BP:PP ratios observed in polar waters. BP was more strongly correlated with chlorophyll (Chl, than with PP, implying that bacteria feed on DOC produced from a variety of trophic levels (e.g. zooplankton sloppy feeding and excretion as well as directly on phytoplankton-derived DOC. The degree of bottom-up control on bacterial abundance was moderate and relatively consistent across entire growing seasons, suggesting that bacteria in the coastal WAP are under consistent DOC limitation. Temperature also influenced BP rates, though its effect was weaker than DOC. We established generalized linear models (GLMs for monthly composites of BP and BB via stepwise regression to explore a set of physical and biogeochemical predictors. Physically, high BP and large BB were shaped by a stratified water-column, similar to forcing mechanisms favoring phytoplankton blooms, but high sea surface temperature (SST also significantly promoted bacterial processes. High BP and large BB were influenced by high PP and bulk DOC concentrations. Based on these findings, we suggest an increasingly important role of marine heterotrophic bacteria in the coastal WAP food-web as climate change introduces a more favorable environmental setting for promoting BP, with increased DOC from retreating glaciers, a more stabilized upper water-column from ice

  16. Spatial variability in photosynthetic and heterotrophic activity drives localized δ13C org fluctuations and carbonate precipitation in hypersaline microbial mats.

    Science.gov (United States)

    Houghton, J; Fike, D; Druschel, G; Orphan, V; Hoehler, T M; Des Marais, D J

    2014-11-01

    Modern laminated photosynthetic microbial mats are ideal environments to study how microbial activity creates and modifies carbon and sulfur isotopic signatures prior to lithification. Laminated microbial mats from a hypersaline lagoon (Guerrero Negro, Baja California, Mexico) maintained in a flume in a greenhouse at NASA Ames Research Center were sampled for δ(13) C of organic material and carbonate to assess the impact of carbon fixation (e.g., photosynthesis) and decomposition (e.g., bacterial respiration) on δ(13) C signatures. In the photic zone, the δ(13) C org signature records a complex relationship between the activities of cyanobacteria under variable conditions of CO2 limitation with a significant contribution from green sulfur bacteria using the reductive TCA cycle for carbon fixation. Carbonate is present in some layers of the mat, associated with high concentrations of bacteriochlorophyll e (characteristic of green sulfur bacteria) and exhibits δ(13) C signatures similar to DIC in the overlying water column (-2.0‰), with small but variable decreases consistent with localized heterotrophic activity from sulfate-reducing bacteria (SRB). Model results indicate respiration rates in the upper 12 mm of the mat alter in situ pH and HCO3- concentrations to create both phototrophic CO2 limitation and carbonate supersaturation, leading to local precipitation of carbonate minerals. The measured activity of SRB with depth suggests they variably contribute to decomposition in the mat dependent on organic substrate concentrations. Millimeter-scale variability in the δ(13) C org signature beneath the photic zone in the mat is a result of shifting dominance between cyanobacteria and green sulfur bacteria with the aggregate signature overprinted by heterotrophic reworking by SRB and methanogens. These observations highlight the impact of sedimentary microbial processes on δ(13) C org signatures; these processes need to be considered when attempting to relate

  17. Rock weathering by indigenous heterotrophic bacteria of Bacillus spp. at different temperature: a laboratory experiment

    Science.gov (United States)

    Štyriaková, I.; Štyriak, I.; Oberhänsli, H.

    2012-07-01

    The bio-weathering of basalt, granite and gneiss was experimentally investigated in this study. These rock-forming minerals weathered more rapidly via the ubiquitous psychrotrophic heterotrophic bacteria . With indigenous bacteria of Bacillus spp. from sediments of Lake Baikal, we traced the degradation process of silicate minerals to understand the weathering processes occurring at the change temperature in the subsurface environment with organic input. The bacteria mediated dissolution of minerals was monitored with solution and solid chemistry, X-ray analyses as well as microscopic techniques. We determined the impact of the bacteria on the mineral surface and leaching of K, Ca, Mg, Si, Fe, and Al from silicate minerals. In the samples the release of major structural elements of silicates was used as an overall indicator of silicate mineral degradation at 4°C and 18°C from five medium exchanges over 255 days of rock bioleaching. The increase of temperature importantly affected the efficiency of Fe extraction from granite and basalt as well as Si extraction from granite and gneiss. In comparison with elemental extraction order at 4°C, Ca was substituted first by Fe or Si. It is evident that temperature influences rock microbial weathering and results in a change of elements extraction.

  18. Nutritional quality of fish faeces is enhanced by highly unsaturated fatty acid-producing heterotrophic protozoa

    Science.gov (United States)

    Fujibayashi, Megumu; Tanaka, Nobuyuki; Hashido, Shun; Takasawa, Aya; Nishimura, Osamu

    2018-05-01

    Highly unsaturated fatty acids such as 20:5n3 (EPA) are both hormone precursors and cell membrane components, making them important nutrients for aquatic animals. Many animals must obtain EPA from their diets because they cannot synthesize enough EPA to meet their requirements, and algae are the main source of EPA in aquatic ecosystems. In a previous study, we detected EPA in the faeces of Danio rerio, a freshwater fish, even though the fish consumed a green algae diet that did not contain EPA. The objective of this study was to determine why EPA was detected in fish faeces. A significant positive relationship was detected between the number of heterotrophic protozoa and the concentration of EPA in the faeces, which suggests that this EPA was of protozoan origin. In addition, another experiment showed that protozoa adhered to faeces far more than the green algal diet remnants, which indicates that protozoa preferred to swarm on faeces. Furthermore, we cultured protozoa in an EPA-free medium and fed them a bacterial diet also lacking EPA, and found that Cyclidium sp. synthesized EPA de novo. The results demonstrate that protozoa produce essential fatty acids and enhance the nutritional quality of animal faeces in detritus-based food webs in freshwater ecosystems.

  19. Biotransformation of dichlorodiphenyltrichloroethane in the benthic polychaete, Nereis succinea: quantitative estimation by analyzing the partitioning of chemicals between gut fluid and lipid.

    Science.gov (United States)

    Wang, Fei; Pei, Yuan-yuan; You, Jing

    2015-02-01

    Biotransformation plays an important role in the bioaccumulation and toxicity of a chemical in biota. Dichlorodiphenyltrichloroethane (DDT) commonly co-occurs with its metabolites (dichlorodiphenyldichloroethane [DDD] and dichlorodiphenyldichloroethylene [DDE]), in the environment; thus it is a challenge to accurately quantify the biotransformation rates of DDT and distinguish the sources of the accumulated metabolites in an organism. The present study describes a method developed to quantitatively analyze the biotransformation of p,p'-DDT in the benthic polychaete, Nereis succinea. The lugworms were exposed to sediments spiked with DDT at various concentrations for 28 d. Degradation of DDT to DDD and DDE occurred in sediments during the aging period, and approximately two-thirds of the DDT remained in the sediment. To calculate the biotransformation rates, residues of individual compounds measured in the bioaccumulation testing (after biotransformation) were compared with residues predicted by analyzing the partitioning of the parent and metabolite compounds between gut fluid and tissue lipid (before biotransformation). The results suggest that sediment ingestion rates decreased when DDT concentrations in sediment increased. Extensive biotransformation of DDT occurred in N. succinea, with 86% of DDT being metabolized to DDD and biotransformation, and the remaining 30% was from direct uptake of sediment-associated DDD. In addition, the biotransformation was not dependent on bulk sediment concentrations, but rather on bioaccessible concentrations of the chemicals in sediment, which were quantified by gut fluid extraction. The newly established method improved the accuracy of prediction of the bioaccumulation and toxicity of DDTs. © 2014 SETAC.

  20. Toxicological benchmarks for screening potential contaminants of concern for effects on soil and litter invertebrates and heterotrophic process

    International Nuclear Information System (INIS)

    Will, M.E.; Suter, G.W. II.

    1994-09-01

    One of the initial stages in ecological risk assessments for hazardous waste sites is the screening of contaminants to determine which of them are worthy of further consideration as open-quotes contaminants of potential concern.close quotes This process is termed open-quotes contaminant screening.close quotes It is performed by comparing measured ambient concentrations of chemicals to benchmark concentrations. Currently, no standard benchmark concentrations exist for assessing contaminants in soil with respect to their toxicity to soil- and litter-dwelling invertebrates, including earthworms, other micro- and macroinvertebrates, or heterotrophic bacteria and fungi. This report presents a standard method for deriving benchmarks for this purpose, sets of data concerning effects of chemicals in soil on invertebrates and soil microbial processes, and benchmarks for chemicals potentially associated with United States Department of Energy sites. In addition, literature describing the experiments from which data were drawn for benchmark derivation. Chemicals that are found in soil at concentrations exceeding both the benchmarks and the background concentration for the soil type should be considered contaminants of potential concern

  1. Toxicological benchmarks for screening potential contaminants of concern for effects on soil and litter invertebrates and heterotrophic process

    Energy Technology Data Exchange (ETDEWEB)

    Will, M.E.; Suter, G.W. II

    1994-09-01

    One of the initial stages in ecological risk assessments for hazardous waste sites is the screening of contaminants to determine which of them are worthy of further consideration as {open_quotes}contaminants of potential concern.{close_quotes} This process is termed {open_quotes}contaminant screening.{close_quotes} It is performed by comparing measured ambient concentrations of chemicals to benchmark concentrations. Currently, no standard benchmark concentrations exist for assessing contaminants in soil with respect to their toxicity to soil- and litter-dwelling invertebrates, including earthworms, other micro- and macroinvertebrates, or heterotrophic bacteria and fungi. This report presents a standard method for deriving benchmarks for this purpose, sets of data concerning effects of chemicals in soil on invertebrates and soil microbial processes, and benchmarks for chemicals potentially associated with United States Department of Energy sites. In addition, literature describing the experiments from which data were drawn for benchmark derivation. Chemicals that are found in soil at concentrations exceeding both the benchmarks and the background concentration for the soil type should be considered contaminants of potential concern.

  2. Variation of a benthic heterotrophic bacteria community with different respiratory metabolisms in Coyuca de Benítez coastal lagoon (Guerrero, Mexico

    Directory of Open Access Journals (Sweden)

    María Jesús Ferrara-Guerrero

    2007-03-01

    Full Text Available The fluctuations of the number, biomass and composition of the heterotrophic community were studied daily for two days, according to depth, pH, Eh, O2 and organic carbon concentration within a zone of the canal between the Coyuca de Benítez lagoon (Guerrero, Mexico and the coastal waters. At the three moments of the day studied (6 am, 2 pm and 10 pm, the oxygen concentrations in the overlying water and in the superficial sediment layer were near air-saturation in the diurnal samplings (582 µM at 6 am and 665 µM at 2 pm, and sub-satured during the night (158 µM. In the sediments, the models of vertical distribution of Eh and organic carbon distributions were very irregular due to the bio-perturbation of the benthic, meio- and macrofauna, whose activity allows the superficial organic carbon to migrate towards sediment deeper layers. Vertical distribution of the different viable bacteria populations seems to be related to the hydrodynamic patterns of the communicating canal and sediments heterogeneity. In the sediment column, the heterotrophic bacteria total number varied from 6.8 to 20.3 x 108 cells cm-3. The highest heterotrophic bacterial biomass values were encountered during the diurnal samplings (39.2 µgC.l-1 at 6 am and 34.4 µgC.l-1 at 2 pm and the lowest during the night (9.7 µgC.l-1. The fluctuations of viable heterotrophic bacteria populations with different respiratory metabolisms (aerobic, microaerophilic and anaerobic can be explained by the existence of suboxic microniches that appear when particles of sediment are resuspended due to the water circulation and the benthic infauna excavating activity, that allows the supernatant water oxygen to penetrate through its galleries towards deeper sediment zones. The statistical analysis (Multiple lineal regression model r²≥ 0.5 showed that the on the whole, the hydrological parameters are not influence over the bacterial number and bacterial biomass distribution (r²≤ 0

  3. A meta-analysis approach to the effects of fish farming on soft bottom polychaeta assemblages in temperate regions

    International Nuclear Information System (INIS)

    Martinez-Garcia, Elena; Sanchez-Jerez, Pablo; Aguado-Giménez, Felipe; Ávila, Pablo; Guerrero, Alejandro; Sánchez-Lizaso, Jose Luis; Fernandez-Gonzalez, Victoria; González, Nieves; Gairin, Joan Ignasi; Carballeira, Carlos; García-García, Benjamín; Carreras, Jordi

    2013-01-01

    Highlights: ► This study was carried out in ten fish farms along the Spanish coast. ► Fish farm caused a decline in abundance and family richness in polychaete assemblages. ► There are two main groups of polychaeta, sensitive families and tolerant families. ► The main influence is associated to percentage of silt and clays. ► Total free sulfides, silt and clays and 15 N, have influence on polychaete populations. -- Abstract: Marine fish farms could cause environmental disturbances on the sediment due to uneaten food and fish faeces that impact the marine benthos. Polychaete assemblages are considered good indicators of environmental perturbations. The present study aimed to establish groups of polychaetes as potential indicators of fish farm pollution. This study was carried out in ten fish farms along the Spanish coast. Changes in polychaete assemblage were analyzed with meta-analysis and multivariate techniques. Abundance, richness and diversity showed significant decreases under fish farm conditions. Distribution patterns of polychaetes responded to combinations of physicochemical variables. The main ones are sulfide concentration, silt and clays percentage, and stable nitrogen isotope ratio. The results showed that some families are tolerant, Capitellidae, Dorvilleidae, Glyceridae, Nereididae, Oweniidae and Spionidae; while others are sensitive to fish farm pollution, Magelonidae, Maldanidae, Nephtyidae, Onuphidae, Paralacydoniidae, Paraonide, Sabellidae and also Cirratulidae in spite of being reported as a tolerant family

  4. The impact of industrial pollution on macrobenthic fauna communities

    African Journals Online (AJOL)

    USE

    petrochemical industries (station located in Ghanam creek) had higher species diversity and ... that Polychaetes, a biotic index of pollution biotic, were more abundant. Although Polychaetes ..... Marine benthic hypoxia: A review of its ecological ...

  5. Chemosynthetic trophic support for the benthic community at an intertidal cold seep site at Mocha Island off central Chile

    Science.gov (United States)

    Sellanes, Javier; Zapata-Hernández, Germán; Pantoja, Silvio; Jessen, Gerdhard L.

    2011-12-01

    We analyzed C and N stable isotope ratios of benthic fauna and their potential food sources at an intertidal methane seep site and a control site without emanation at Mocha Island (central Chile). The objective was to trace the origin of the main food sources used by the local heterotrophic fauna, based on the hypothesis that chemosynthetic production could be partially fueling the local food web at the seep site. Food sources sampled at both sites included macroalgae, particulate organic matter and bacteria-like filaments found growing over the red algae Gelidium lingulatum within the areas of active methane release. At the control site, located 11 km away from the gas emanation, fauna exhibited moderate δ 13C values ranging from -16.2‰ (in a nereid polychaete) to -14.8‰ (in a cirolanid isopod), which were consistent with those of the potential photosynthetic food sources sampled at this site (-20.2 to -16.5‰). δ 13C values of the photosynthetic food sources at the seep site similarly ranged between -25.4 and -17.9‰. However, a portion of the animals at this site were consistently more 13C-depleted, with δ 13C values close to that of the seeping methane (-43.8‰) and the bacteria-like filaments (-39.2 ± 2.5‰) also collected at this site. Specific examples were the Marphysa sp. polychaetes (δ 13C = -44.7 ± 0.6‰), the Schistomeringos sp. dorvilleid polychaetes (δ 13C = -42.9‰), and the tanaid crustacean Zeuxo marmoratus (δ 13C = -37.3 ± 0.2‰). The significantly higher δ 13C values of the herbivorous gastropod Tegula atra at the seep site (-29.3 ± 3.1‰) than at the control site (-12.6 ± 0.3‰) also indicated differences among sites of the preferred carbon sources of this species. Mixing model estimates indicate that at the seep site bacteria-like filaments could be contributing up to ˜60% of the assimilated diet of selected invertebrates. Furthermore, several indicators of trophic structure, based in isotopic niche metrics, indicate a

  6. Reduction of ferric iron by acidophilic heterotrophic bacteria: evidence for constitutive and inducible enzyme systems in Acidiphilium spp.

    Science.gov (United States)

    Johnson, D B; Bridge, T A M

    2002-01-01

    To compare the abilities of two obligately acidophilic heterotrophic bacteria, Acidiphilium acidophilum and Acidiphilium SJH, to reduce ferric iron to ferrous when grown under different culture conditions. Bacteria were grown in batch culture, under different aeration status, and in the presence of either ferrous or ferric iron. The specific rates of ferric iron reduction by fermenter-grown Acidiphilium SJH were unaffected by dissolved oxygen (DO) concentrations, while iron reduction by A. acidophilum was highly dependent on DO concentrations in the growth media. The ionic form of iron present (ferrous or ferric) had a minimal effect on the abilities of harvested cells to reduce ferric iron. Whole cell protein profiles of Acidiphilium SJH were very similar, regardless of the DO status of the growth medium, while additional proteins were present in A. acidophilum grown microaerobically compared with aerobically-grown cells. The dissimilatory reduction of ferric iron is constitutive in Acidiphilium SJH while it is inducible in A. acidophilum. Ferric iron reduction by Acidiphilium spp. may occur in oxygen-containing as well as anoxic acidic environments. This will detract from the effectiveness of bioremediation systems where removal of iron from polluted waters is mediated via oxidation and precipitation of the metal.

  7. Genetic analysis of amino acid transport in the facultatively heterotrophic cyanobacterium Synechocystis sp. Strain 6803

    International Nuclear Information System (INIS)

    Labarre, J.; Thuriaux, P.; Chauvat, F.

    1987-01-01

    The existence of active transport systems (permeases) operating on amino acids in the photoautotrophic cyanobacterium Synechocystis sp. strain 6803 was demonstrated by following the initial rates of uptake with 14 C-labeled amino acids, measuring the intracellular pools of amino acids, and isolating mutants resistant to toxic amino acids. One class of mutants (Pfa1) corresponds to a regulatory defect in the biosynthesis of the aromatic amino acids, but two other classes (Can1 and Aza1) are defective in amino acid transport. The Can1 mutants are defective in the active transport of three basic amino acids (arginine, histidine, and lysine) and in one of two transport systems operating on glutamine. The Aza1 mutants are not affected in the transport of the basic amino acids but have lost the capacity to transport all other amino acids except glutamate. The latter amino acid is probably transported by a third permease which could be identical to the Can1-independent transport operating on glutamine. Thus, genetic evidence suggests that strain 6803 has only a small number of amino acid transport systems with fairly broad specificity and that, with the exception of glutamine, each amino acid is accumulated by only one major transport system. Compared with heterotrophic bacteria such as Escherichia coli, these permeases are rather inefficient in terms of affinity (apparent K/sub m/ ranging from 6 to 60 μM) and of V/sub max/

  8. Novel heterotrophic nitrogen removal and assimilation characteristic of the newly isolated bacterium Pseudomonas stutzeri AD-1.

    Science.gov (United States)

    Qing, Hui; Donde, Oscar Omondi; Tian, Cuicui; Wang, Chunbo; Wu, Xingqiang; Feng, Shanshan; Liu, Yao; Xiao, Bangding

    2018-04-18

    AD-1, an aerobic denitrifier, was isolated from activated sludge and identified as Pseudomonas stutzeri. AD-1 completely removed NO 3 - or NO 2 - and removed 99.5% of NH 4 + during individual culturing in a broth medium with an initial nitrogen concentration of approximately 50 mg L -1 . Results showed that larger amounts of nitrogen were removed through assimilation by the bacteria. And when NH 4 + was used as the sole nitrogen source in the culture medium, neither NO 2 - nor NO 3 - was detected, thus indicating that AD-1 may not be a heterotrophic nitrifier. Only trace amount of N 2 O was detected during the denitrification process. Single factor experiments indicated that the optimal culture conditions for AD-1 were: a carbon-nitrogen ratio (C/N) of 15, a temperature of 25°C and sodium succinate or glucose as a carbon source. In conclusion, due to the ability of AD-1 to utilize nitrogen of different forms with high efficiencies for its growth while producing only trace emissions of N 2 O, the bacterium had outstanding potential to use in the bioremediation of high-nitrogen-containing wastewaters. Meanwhile, it may also be a proper candidate for biotreatment of high concentration organic wastewater. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  9. Autotrophic and heterotrophic acquisition of carbon and nitrogen by a mixotrophic chrysophyte established through stable isotope analysis.

    Science.gov (United States)

    Terrado, Ramon; Pasulka, Alexis L; Lie, Alle A-Y; Orphan, Victoria J; Heidelberg, Karla B; Caron, David A

    2017-09-01

    Collectively, phagotrophic algae (mixotrophs) form a functional continuum of nutritional modes between autotrophy and heterotrophy, but the specific physiological benefits of mixotrophic nutrition differ among taxa. Ochromonas spp. are ubiquitous chrysophytes that exhibit high nutritional flexibility, although most species generally fall towards the heterotrophic end of the mixotrophy spectrum. We assessed the sources of carbon and nitrogen in Ochromonas sp. strain BG-1 growing mixotrophically via short-term stable isotope probing. An axenic culture was grown in the presence of either heat-killed bacteria enriched with 15 N and 13 C, or unlabeled heat-killed bacteria and labeled inorganic substrates ( 13 C-bicarbonate and 15 N-ammonium). The alga exhibited high growth rates (up to 2 divisions per day) only until heat-killed bacteria were depleted. NanoSIMS and bulk IRMS isotope analyses revealed that Ochromonas obtained 84-99% of its carbon and 88-95% of its nitrogen from consumed bacteria. The chrysophyte assimilated inorganic 13 C-carbon and 15 N-nitrogen when bacterial abundances were very low, but autotrophic (photosynthetic) activity was insufficient to support net population growth of the alga. Our use of nanoSIMS represents its first application towards the study of a mixotrophic alga, enabling a better understanding and quantitative assessment of carbon and nutrient acquisition by this species.

  10. Light enhanced the accumulation of total fatty acids (TFA) and docosahexaenoic acid (DHA) in a newly isolated heterotrophic microalga Crypthecodinium sp. SUN.

    Science.gov (United States)

    Sun, Dongzhe; Zhang, Zhao; Mao, Xuemei; Wu, Tao; Jiang, Yue; Liu, Jin; Chen, Feng

    2017-03-01

    In the present study, light illumination was found to be efficient in elevating the total fatty acid content in a newly isolated heterotrophic microalga, Crypthecodinium sp. SUN. Under light illumination, the highest total fatty acid and DHA contents were achieved at 96h as 24.9% of dry weight and 82.8mgg -1 dry weight, respectively, which were equivalent to 1.46-fold and 1.68-fold of those under the dark conditions. The elevation of total fatty acid content was mainly contributed by an increase of neutral lipids at the expense of starches. Moreover, light was found to alter the cell metabolism and led to a higher specific growth rate, higher glucose consumption rate and lower non-motile cell percentage. This is the first report that light can promote the total fatty acids accumulation in Crypthecodinium without growth inhibition. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Transmission of white spot syndrome virus (WSSV) from Dendronereis spp. (Peters) (Nereididae) to penaeid shrimp

    NARCIS (Netherlands)

    Haryadi, D.; Verreth, J.A.J.; Verdegem, M.C.J.; Vlak, J.M.

    2015-01-01

    Dendronereis spp. (Peters) (Nereididae) is a common polychaete in shrimp ponds built on intertidal land and is natural food for shrimp in traditionally managed ponds in Indonesia. White spot syndrome virus (WSSV), an important viral pathogen of the shrimp, can replicate in this polychaete (Desrina

  12. Dynamic characterization of external and internal mass transport in heterotrophic biofilms from microsensors measurements.

    Science.gov (United States)

    Guimerà, Xavier; Dorado, Antonio David; Bonsfills, Anna; Gabriel, Gemma; Gabriel, David; Gamisans, Xavier

    2016-10-01

    Knowledge of mass transport mechanisms in biofilm-based technologies such as biofilters is essential to improve bioreactors performance by preventing mass transport limitation. External and internal mass transport in biofilms was characterized in heterotrophic biofilms grown on a flat plate bioreactor. Mass transport resistance through the liquid-biofilm interphase and diffusion within biofilms were quantified by in situ measurements using microsensors with a high spatial resolution (mass transport coefficients. The sensitivity of external and internal mass transport resistances to flow conditions within the range of typical fluid velocities over biofilms (Reynolds numbers between 0.5 and 7) was assessed. Estimated external mass transfer coefficients at different liquid phase flow velocities showed discrepancies with studies considering laminar conditions in the diffusive boundary layer near the liquid-biofilm interphase. The correlation of effective diffusivity with flow velocities showed that the heterogeneous structure of biofilms defines the transport mechanisms inside biofilms. Internal mass transport was driven by diffusion through cell clusters and aggregates at Re below 2.8. Conversely, mass transport was driven by advection within pores, voids and water channels at Re above 5.6. Between both flow velocities, mass transport occurred by a combination of advection and diffusion. Effective diffusivities estimated at different biofilm densities showed a linear increase of mass transport resistance due to a porosity decrease up to biofilm densities of 50 g VSS·L(-1). Mass transport was strongly limited at higher biofilm densities. Internal mass transport results were used to propose an empirical correlation to assess the effective diffusivity within biofilms considering the influence of hydrodynamics and biofilm density. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Uptake, metabolism and sub-lethal effects of BDE-47 in two estuarine invertebrates with different trophic positions

    International Nuclear Information System (INIS)

    Díaz-Jaramillo, M.; Miglioranza, K.S.B.; Gonzalez, M.; Barón, E.; Monserrat, J.M.; Eljarrat, E.; Barceló, D.

    2016-01-01

    Two microcosm types -sediment-biota and biota-biota- were constructed to simulate different pathways of BDE-47 uptake, metabolism and oxidative stress effects in two key estuarine invertebrates (polychaete Laeonereis acuta and crab Cyrtograpsus angulatus). In the sediment-biota experiment, both species were exposed to spiked sediments; an environmentally reported and a high concentration of BDE-47 for 2 weeks. In the biota-biota experiment, crabs were fed with polychaetes pre-exposed to BDE-47 in the sediment-biota experiment. The sediment-biota experiment first revealed that polychaetes significantly accumulated BDE-47 (biota-sediment accumulation factor >2; p < 0.05) to a much greater extent than the crab organs (muscle, hepatopancreas, gills) at both sediment concentrations. For oxidative stress responses, polychaete and crab tissues exposed to spiked sediment showed a significant increase (p < 0.05) of only glutathione S-transferase (GST) activity with respect to controls in both BDE-47 concentrations. No lipid peroxidation (TBARS) or total antioxidant capacity (ACAP) changes were evident in the species or organs exposed to either BDE-47 sediment concentration. The biota-biota experiment showed that feeding crabs with pre-exposed polychaetes caused BDE-47 accumulation in organs as well as significant amounts of BDE-47 eliminated through feces (p < 0.05). Unlike the sediment-biota exposure, crabs fed with pre-exposed BDE-47 polychaetes showed the most conspicuous oxidative stress responses. Significant changes in GST and ACAP in both hepatopancreas and gills, in addition to enhanced TBARS levels in the hepatopancreas with respect to controls (p < 0.05), revealed that BDE-47 assimilated by invertebrates represents a potential source of toxicity to their predators. No methoxylated metabolites (MeO-PBDEs) were detected during BDE-47 metabolism in the invertebrates in either of the two different exposure types. In contrast, hydroxylated metabolites (OH

  14. Diurnal Patterns of Heterotrophic and Autotrophic Soil Respiration in Maize and Switchgrass Bioenergy Cropping Systems

    Science.gov (United States)

    von Haden, A.; Marin-Spiotta, E.; Jackson, R. D.; Kucharik, C. J.

    2016-12-01

    A high proportion of carbon lost from terrestrial ecosystems occurs via soil CO2 respiration. Soil respiration is comprised of two contrasting sources: heterotrophic respiration (RH) from the decomposition of organic matter and autotrophic respiration (RA) from plant root metabolism. Since the two sources of soil respiration vary widely in their origin, the controls of each source are also likely to differ. However, the challenge of partitioning soil respiration sources in situ has limited our mechanistic understanding of RH and RA. Our objective was to evaluate the in situ diurnal controls of RH and RA in maize (Zea mays L.) and switchgrass (Panicum virgatum L.) bioenergy cropping systems. We hypothesized that both RH and RA would follow diurnal soil temperature trends, but that RA would also respond to diel patterns of photosynthetically active radiation (PAR). We also expected that diurnal soil respiration patterns would vary significantly within the growing season. We evaluated our hypothesis with six diurnal soil respiration campaigns during the 2015 and 2016 growing seasons at Arlington, WI, USA. RH showed clear oscillating diel trends, typically peaking in the mid-afternoon when near-surface soil temperatures were highest. Diurnal RA patterns were more nuanced than RH, but were generally highest in the late afternoon and showed the most pronounced diel trends during peak growing season in July. RA also tended to spike in concert with PAR, but this effect was much more prominent in maize than switchgrass. Continuing efforts will attempt to quantitatively separate the effects of soil temperature and PAR on RA.

  15. Key factors influencing rates of heterotrophic sulfate reduction in active seafloor hydrothermal massive sulfide deposits

    Directory of Open Access Journals (Sweden)

    Kiana Laieikawai Frank

    2015-12-01

    Full Text Available Hydrothermal vents are thermally and geochemically dynamic habitats, and the organisms therein are subject to steep gradients in temperature and chemistry. To date, the influence of these environmental dynamics on microbial sulfate reduction has not been well constrained. Here, via multivariate experiments, we evaluate the effects of key environmental variables (temperature, pH, H2S, SO42-, DOC on sulfate reduction rates and metabolic energy yields in material recovered from a hydrothermal flange from the Grotto edifice in the Main Endeavor Field, Juan de Fuca Ridge. Sulfate reduction was measured in batch reactions across a range of physico-chemical conditions. Temperature and pH were the strongest stimuli, and maximum sulfate reduction rates were observed at 50 °C and pH 6, suggesting that the in situ community of sulfate-reducing organisms in Grotto flanges may be most active in a slightly acidic and moderate thermal/chemical regime. At pH 4, sulfate reduction rates increased with sulfide concentrations most likely due to the mitigation of metal toxicity. While substrate concentrations also influenced sulfate reduction rates, energy-rich conditions muted the effect of metabolic energetics on sulfate reduction rates. We posit that variability in sulfate reduction rates reflect the response of the active microbial consortia to environmental constraints on in situ microbial physiology, toxicity, and the type and extent of energy limitation. These experiments help to constrain models of the spatial contribution of heterotrophic sulfate reduction within the complex gradients inherent to seafloor hydrothermal deposits.

  16. The application of mass and energy conservation laws in physiologically structured population models of heterotrophic organisms

    Science.gov (United States)

    Kooijman; Kooi; Hallam

    1999-04-07

    Rules for energy uptake, and subsequent utilization, form the basis of population dynamics and, therefore, explain the dynamics of the ecosystem structure in terms of changes in standing crops and size distributions of individuals. Mass fluxes are concomitant with energy flows and delineate functional aspects of ecosystems by defining the roles of individuals and populations. The assumption of homeostasis of body components, and an assumption about the general structure of energy budgets, imply that mass fluxes can be written as weighted sums of three organizing energy fluxes with the weight coefficients determined by the conservation law of mass. These energy fluxes are assimilation, maintenance and growth, and provide a theoretical underpinning of the widely applied empirical method of indirect calorimetry, which relates dissipating heat linearly to three mass fluxes: carbon dioxide production, oxygen consumption and N-waste production. A generic approach to the stoichiometry of population energetics from the perspective of the individual organism is proposed and illustrated for heterotrophic organisms. This approach indicates that mass transformations can be identified by accounting for maintenance requirements and overhead costs for the various metabolic processes at the population level. The theoretical background for coupling the dynamics of the structure of communities to nutrient cycles, including the water balance, as well as explicit expressions for the dissipating heat at the population level are obtained based on the conservation law of energy. Specifications of the general theory employ the Dynamic Energy Budget model for individuals. Copyright 1999 Academic Press.

  17. Autotrophic and heterotrophic acquisition of carbon and nitrogen by a mixotrophic chrysophyte established through stable isotope analysis

    Science.gov (United States)

    Terrado, Ramon; Pasulka, Alexis L; Lie, Alle A-Y; Orphan, Victoria J; Heidelberg, Karla B; Caron, David A

    2017-01-01

    Collectively, phagotrophic algae (mixotrophs) form a functional continuum of nutritional modes between autotrophy and heterotrophy, but the specific physiological benefits of mixotrophic nutrition differ among taxa. Ochromonas spp. are ubiquitous chrysophytes that exhibit high nutritional flexibility, although most species generally fall towards the heterotrophic end of the mixotrophy spectrum. We assessed the sources of carbon and nitrogen in Ochromonas sp. strain BG-1 growing mixotrophically via short-term stable isotope probing. An axenic culture was grown in the presence of either heat-killed bacteria enriched with 15N and 13C, or unlabeled heat-killed bacteria and labeled inorganic substrates (13C-bicarbonate and 15N-ammonium). The alga exhibited high growth rates (up to 2 divisions per day) only until heat-killed bacteria were depleted. NanoSIMS and bulk IRMS isotope analyses revealed that Ochromonas obtained 84–99% of its carbon and 88–95% of its nitrogen from consumed bacteria. The chrysophyte assimilated inorganic 13C-carbon and 15N-nitrogen when bacterial abundances were very low, but autotrophic (photosynthetic) activity was insufficient to support net population growth of the alga. Our use of nanoSIMS represents its first application towards the study of a mixotrophic alga, enabling a better understanding and quantitative assessment of carbon and nutrient acquisition by this species. PMID:28524870

  18. Removal of highly elevated nitrate from drinking water by pH-heterogenized heterotrophic denitrification facilitated with ferrous sulfide-based autotrophic denitrification.

    Science.gov (United States)

    Huang, Bin; Chi, Guangyu; Chen, Xin; Shi, Yi

    2011-11-01

    The performance of acetic acid-supported pH-heterogenized heterotrophic denitrification (HD) facilitated with ferrous sulfide-based autotrophic denitrification (AD) was investigated in upflow activated carbon-packed column reactors for reliable removal of highly elevated nitrate (42 mg NO(3)-Nl(-1)) in drinking water. The use of acetic acid as substrate provided sufficient internal carbon dioxide to completely eliminate the need of external pH adjustment for HD, but simultaneously created vertically heterogenized pH varying from 4.8 to 7.8 in the HD reactor. After 5-week acclimation, the HD reactor developed a moderate nitrate removal capacity with about one third of nitrate removal occurring in the acidic zone (pH 4.8-6.2). To increase the treatment reliability, acetic acid-supported HD was operated under 10% carbon limitation to remove >85% of nitrate, and ferrous sulfide-based AD was supplementally operated to remove residual nitrate and formed nitrite without excess of soluble organic carbon, nitrite or sulfate in the final effluent. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Biomass and lipid production of Chlorella protothecoides under heterotrophic cultivation on a mixed waste substrate of brewer fermentation and crude glycerol.

    Science.gov (United States)

    Feng, Xiaoyu; Walker, Terry H; Bridges, William C; Thornton, Charles; Gopalakrishnan, Karthik

    2014-08-01

    Biomass and lipid accumulation of heterotrophic microalgae Chlorella protothecoides by supplying mixed waste substrate of brewer fermentation and crude glycerol were investigated. The biomass concentrations of the old and the new C. protothecoides strains on day 6 reached 14.07 and 12.73 g/L, respectively, which were comparable to those in basal medium with supplement of glucose and yeast extract (BM-GY) (14.47 g/L for old strains and 11.43 g/L for new strains) (P>0.05). Approximately 81.5% of total organic carbon and 65.1% of total nitrogen in the mixed waste were effectively removed. The accumulated lipid productivities of the old and the new C. protothecoides strains in BM-GY were 2.07 and 1.61 g/L/day, respectively, whereas in the mixed waste, lipid productivities could reach 2.12 and 1.81 g/L/day, respectively. Our result highlights a new approach of mixing carbon-rich and nitrogen-rich wastes as economical and practical alternative substrates for biofuel production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Note on an invasion of intertidal zoanthid colonies by a chaetopterid ...

    African Journals Online (AJOL)

    At Park Rynie Beach on the KwaZulu-Natal coast, South Africa, four species of zoanthids were invaded by a sand-tube building polychaete Mesochaetopterus minutus. It is a small polychaete about 15 mm long, which occurs gregariously in dense masses of sandy tubes. M. minutus is an opportunistic species that exploits ...

  1. Ubiquity and diversity of heterotrophic bacterial nasA genes in diverse marine environments.

    Directory of Open Access Journals (Sweden)

    Xuexia Jiang

    Full Text Available Nitrate uptake by heterotrophic bacteria plays an important role in marine N cycling. However, few studies have investigated the diversity of environmental nitrate assimilating bacteria (NAB. In this study, the diversity and biogeographical distribution of NAB in several global oceans and particularly in the western Pacific marginal seas were investigated using both cultivation and culture-independent molecular approaches. Phylogenetic analyses based on 16S rRNA and nasA (encoding the large subunit of the assimilatory nitrate reductase gene sequences indicated that the cultivable NAB in South China Sea belonged to the α-Proteobacteria, γ-Proteobacteria and CFB (Cytophaga-Flavobacteria-Bacteroides bacterial groups. In all the environmental samples of the present study, α-Proteobacteria, γ-Proteobacteria and Bacteroidetes were found to be the dominant nasA-harboring bacteria. Almost all of the α-Proteobacteria OTUs were classified into three Roseobacter-like groups (I to III. Clone library analysis revealed previously underestimated nasA diversity; e.g. the nasA gene sequences affiliated with β-Proteobacteria, ε-Proteobacteria and Lentisphaerae were observed in the field investigation for the first time, to the best of our knowledge. The geographical and vertical distributions of seawater nasA-harboring bacteria indicated that NAB were highly diverse and ubiquitously distributed in the studied marginal seas and world oceans. Niche adaptation and separation and/or limited dispersal might mediate the NAB composition and community structure in different water bodies. In the shallow-water Kueishantao hydrothermal vent environment, chemolithoautotrophic sulfur-oxidizing bacteria were the primary NAB, indicating a unique nitrate-assimilating community in this extreme environment. In the coastal water of the East China Sea, the relative abundance of Alteromonas and Roseobacter-like nasA gene sequences responded closely to algal blooms, indicating

  2. Are variations in heterotrophic soil respiration related to changes in substrate availability and microbial biomass carbon in the subtropical forests?

    Science.gov (United States)

    Wei, Hui; Chen, Xiaomei; Xiao, Guoliang; Guenet, Bertrand; Vicca, Sara; Shen, Weijun

    2015-12-16

    Soil temperature and moisture are widely-recognized controlling factors on heterotrophic soil respiration (Rh), although they often explain only a portion of Rh variability. How other soil physicochemical and microbial properties may contribute to Rh variability has been less studied. We conducted field measurements on Rh half-monthly and associated soil properties monthly for two years in four subtropical forests of southern China to assess influences of carbon availability and microbial properties on Rh. Rh in coniferous forest was significantly lower than that in the other three broadleaf species-dominated forests and exhibited obvious seasonal variations in the four forests (P forests. The quantity and decomposability of dissolved organic carbon (DOC) were significantly important to Rh variations, but the effect of DOC content on Rh was confounded with temperature, as revealed by partial mantel test. Microbial biomass carbon (MBC) was significantly related to Rh variations across forests during the warm season (P = 0.043). Our results suggest that DOC and MBC may be important when predicting Rh under some conditions, and highlight the complexity by mutual effects of them with environmental factors on Rh variations.

  3. Flow cytometric bacterial cell counts challenge conventional heterotrophic plate counts for routine microbiological drinking water monitoring

    KAUST Repository

    Van Nevel, S.

    2017-02-08

    Drinking water utilities and researchers continue to rely on the century-old heterotrophic plate counts (HPC) method for routine assessment of general microbiological water quality. Bacterial cell counting with flow cytometry (FCM) is one of a number of alternative methods that challenge this status quo and provide an opportunity for improved water quality monitoring. After more than a decade of application in drinking water research, FCM methodology is optimised and established for routine application, supported by a considerable amount of data from multiple full-scale studies. Bacterial cell concentrations obtained by FCM enable quantification of the entire bacterial community instead of the minute fraction of cultivable bacteria detected with HPC (typically < 1% of all bacteria). FCM measurements are reproducible with relative standard deviations below 3% and can be available within 15 min of samples arriving in the laboratory. High throughput sample processing and complete automation are feasible and FCM analysis is arguably less expensive than HPC when measuring more than 15 water samples per day, depending on the laboratory and selected staining procedure(s). Moreover, many studies have shown FCM total (TCC) and intact (ICC) cell concentrations to be reliable and robust process variables, responsive to changes in the bacterial abundance and relevant for characterising and monitoring drinking water treatment and distribution systems. The purpose of this critical review is to initiate a constructive discussion on whether FCM could replace HPC in routine water quality monitoring. We argue that FCM provides a faster, more descriptive and more representative quantification of bacterial abundance in drinking water.

  4. Flow cytometric bacterial cell counts challenge conventional heterotrophic plate counts for routine microbiological drinking water monitoring

    KAUST Repository

    Van Nevel, S.; Koetzsch, S.; Proctor, C.R.; Besmer, M.D.; Prest, E.I.; Vrouwenvelder, Johannes S.; Knezev, A.; Boon, N.; Hammes, F.

    2017-01-01

    Drinking water utilities and researchers continue to rely on the century-old heterotrophic plate counts (HPC) method for routine assessment of general microbiological water quality. Bacterial cell counting with flow cytometry (FCM) is one of a number of alternative methods that challenge this status quo and provide an opportunity for improved water quality monitoring. After more than a decade of application in drinking water research, FCM methodology is optimised and established for routine application, supported by a considerable amount of data from multiple full-scale studies. Bacterial cell concentrations obtained by FCM enable quantification of the entire bacterial community instead of the minute fraction of cultivable bacteria detected with HPC (typically < 1% of all bacteria). FCM measurements are reproducible with relative standard deviations below 3% and can be available within 15 min of samples arriving in the laboratory. High throughput sample processing and complete automation are feasible and FCM analysis is arguably less expensive than HPC when measuring more than 15 water samples per day, depending on the laboratory and selected staining procedure(s). Moreover, many studies have shown FCM total (TCC) and intact (ICC) cell concentrations to be reliable and robust process variables, responsive to changes in the bacterial abundance and relevant for characterising and monitoring drinking water treatment and distribution systems. The purpose of this critical review is to initiate a constructive discussion on whether FCM could replace HPC in routine water quality monitoring. We argue that FCM provides a faster, more descriptive and more representative quantification of bacterial abundance in drinking water.

  5. Interactions between the Newly Described Small- and Fast-Swimming Mixotrophic Dinoflagellate Yihiella yeosuensis and Common Heterotrophic Protists.

    Science.gov (United States)

    Jeong, Hae Jin; Kang, Hee Chang; You, Ji Hyun; Jang, Se Hyeon

    2018-02-03

    The mixotroph Yihiella yeosuensis is a small- and fast-swimming dinoflagellate. To investigate its protistan predators, interactions between Y. yeosuensis and 11 heterotrophic protists were explored. No potential predators were able to feed on actively swimming Y. yeosuensis cells, which escaped via rapid jumps, whereas Aduncodinium glandula, Oxyrrhis marina, and Strombidinopsis sp. (approximately 150 μm in cell length) were able to feed on weakly swimming cells that could not jump. Furthermore, Gyrodinium dominans, Luciella masanensis, and Pfiesteria piscicida were able to feed on heat-killed Yihiella cells, whereas Gyrodinium moestrupii, Noctiluca scintillans, Oblea rotunda, Polykrikos kofoidii, and Strombidium sp. (20 μm) did not feed on them. Thus, the jumping behavior of Y. yeosuensis might be primarily responsible for the observed lack of predation. With increasing Yihiella concentration, the growth rate of O. marina decreased, whereas that of Strombidinopsis did not change. However, with increasing Yihiella concentration (up to 530 ng C/ml), the ingestion rate of Strombidinopsis on Yihiella increased linearly. The highest ingestion rate was 24.1 ng C per predator per d. The low daily carbon acquisition from Yihiella relative to the body carbon content of Strombidinopsis might be responsible for its negligible growth. Thus, Y. yeosuensis might have an advantage over its competitors due to its low mortality rate. © 2018 The Author(s) Journal of Eukaryotic Microbiology © 2018 International Society of Protistologists.

  6. Culturing Heterotrophic Protists from the Baltic Sea: Mostly the "Usual Suspects" but a Few Novelties as Well.

    Science.gov (United States)

    Weber, Felix; Mylnikov, Alexander P; Jürgens, Klaus; Wylezich, Claudia

    2017-03-01

    The study of cultured strains has a long tradition in protistological research and has greatly contributed to establishing the morphology, taxonomy, and ecology of many protist species. However, cultivation-independent techniques, based on 18S rRNA gene sequences, have demonstrated that natural protistan assemblages mainly consist of hitherto uncultured protist lineages. This mismatch impedes the linkage of environmental diversity data with the biological features of cultured strains. Thus, novel taxa need to be obtained in culture to close this knowledge gap. In this study, traditional cultivation techniques were applied to samples from coastal surface waters and from deep oxygen-depleted waters of the Baltic Sea. Based on 18S rRNA gene sequencing, 126 monoclonal cultures of heterotrophic protists were identified. The majority of the isolated strains were affiliated with already cultured and described taxa, mainly chrysophytes and bodonids. This was likely due to "culturing bias" but also to the eutrophic nature of the Baltic Sea. Nonetheless, ~ 12% of the isolates in our culture collection showed highly divergent 18S rRNA gene sequences compared to those of known organisms and thus may represent novel taxa, either at the species level or at the genus level. Moreover, we also obtained evidence that some of the isolated taxa are ecologically relevant, under certain conditions, in the Baltic Sea. © 2016 The Author(s) Journal of Eukaryotic Microbiology © 2016 International Society of Protistologists.

  7. The B vitamins nicotinamide (B3) and riboflavin (B2) stimulate metamorphosis in larvae of the deposit-feeding polychaete Capitella teleta: implications for a sensory ligand-gated ion channel.

    Science.gov (United States)

    Burns, Robert T; Pechenik, Jan A; Biggers, William J; Scavo, Gia; Lehman, Christopher

    2014-01-01

    Marine sediments can contain B vitamins, presumably incorporated from settled, decaying phytoplankton and microorganisms associated with decomposition. Because B vitamins may be advantageous for the energetically intensive processes of metamorphosis, post-metamorphic growth, and reproduction, we tested several B vitamins to determine if they would stimulate larvae of the deposit-feeding polychaete Capitella teleta to settle and metamorphose. Nicotinamide and riboflavin individually stimulated larvae of C. teleta to settle and metamorphose, generally within 1-2 hours at nicotinamide concentrations as low as 3 µM and riboflavin concentrations as low as 50 µM. More than 80% of the larvae metamorphosed within 30 minutes at a nicotinamide concentration of 7 µM. The pyridine channel agonist pyrazinecarboxamide also stimulated metamorphosis at very low concentrations. In contrast, neither lumichrome, thiamine HCl, pyridoxine HCl, nor vitamin B12 stimulated larvae of C. teleta to metamorphose at concentrations as high as 500 µM. Larvae also did not metamorphose in response to either nicotinamide or pyrazinecarboxamide in calcium-free seawater or with the addition of 4-acetylpyridine, a competitive inhibitor of the pyridine receptor. Together, these results suggest that larvae of C. teleta are responding to nicotinamide and riboflavin via a chemosensory pyridine receptor similar to that previously reported to be present on crayfish chela and involved with food recognition. Our data are the first to implicate B vitamins as possible natural chemical settlement cues for marine invertebrate larvae.

  8. The B Vitamins Nicotinamide (B3) and Riboflavin (B2) Stimulate Metamorphosis in Larvae of the Deposit-Feeding Polychaete Capitella teleta: Implications for a Sensory Ligand-Gated Ion Channel

    Science.gov (United States)

    Burns, Robert T.; Pechenik, Jan A.; Biggers, William J.; Scavo, Gia; Lehman, Christopher

    2014-01-01

    Marine sediments can contain B vitamins, presumably incorporated from settled, decaying phytoplankton and microorganisms associated with decomposition. Because B vitamins may be advantageous for the energetically intensive processes of metamorphosis, post-metamorphic growth, and reproduction, we tested several B vitamins to determine if they would stimulate larvae of the deposit-feeding polychaete Capitella teleta to settle and metamorphose. Nicotinamide and riboflavin individually stimulated larvae of C. teleta to settle and metamorphose, generally within 1–2 hours at nicotinamide concentrations as low as 3 µM and riboflavin concentrations as low as 50 µM. More than 80% of the larvae metamorphosed within 30 minutes at a nicotinamide concentration of 7 µM. The pyridine channel agonist pyrazinecarboxamide also stimulated metamorphosis at very low concentrations. In contrast, neither lumichrome, thiamine HCl, pyridoxine HCl, nor vitamin B12 stimulated larvae of C. teleta to metamorphose at concentrations as high as 500 µM. Larvae also did not metamorphose in response to either nicotinamide or pyrazinecarboxamide in calcium-free seawater or with the addition of 4-acetylpyridine, a competitive inhibitor of the pyridine receptor. Together, these results suggest that larvae of C. teleta are responding to nicotinamide and riboflavin via a chemosensory pyridine receptor similar to that previously reported to be present on crayfish chela and involved with food recognition. Our data are the first to implicate B vitamins as possible natural chemical settlement cues for marine invertebrate larvae. PMID:25390040

  9. Modeling Soil Organic Carbon Turnover in Four Temperate Forests Based on Radiocarbon Measurements of Heterotrophic Respiration and Soil Organic Carbon

    Science.gov (United States)

    Ahrens, B.; Borken, W.; Muhr, J.; Schrumpf, M.; Savage, K. E.; Wutzler, T.; Trumbore, S.; Reichstein, M.

    2011-12-01

    Soils of temperate forests store significant amounts of soil organic matter and are considered to be net sinks of atmospheric CO2. Soil organic carbon (SOC) dynamics have been studied using the Δ14C signature of bulk SOC or different SOC fractions as observational constraints in SOC models. Further, the Δ14C signature of CO2 evolved during the incubation of soil and roots has been widely used together with Δ14C of total soil respiration to partition soil respiration into heterotrophic respiration (Rh) and root respiration. However, these data have rarely been used together as observational constraints to determine SOC turnover times. Here, we present a multiple constraints approach, where we used SOC stock and its Δ14C signature, and heterotrophic respiration and its Δ14C signature to estimate SOC turnover times of a simple serial two-pool model via Bayesian optimization. We used data from four temperate forest ecosystems in Germany and the USA with different disturbance and management histories from selective logging to afforestation in the late 19th and early 20th century. The Δ14C signature of the atmosphere with its prominent bomb peak was used as a proxy for the Δ14C signature of aboveground and belowground litterfall. The Δ14C signature of litterfall was lagged behind the atmospheric signal to account for the period between photosynthetic fixation of carbon and its addition to SOC pools. We showed that the combined use of Δ14C measurements of Rh and SOC stocks helped to better constrain turnover times of the fast pool (primarily by Δ14C of Rh) and the slow pool (primarily by Δ14C of SOC). In particular, by introducing two additional parameters that describe the deviation from steady state of the fast and slow cycling pool for both SOC and SO14C, we were able to demonstrate that we cannot maintain the often used steady-state assumption of SOC models in general. Furthermore, a new transport version of our model, including SOC transport via

  10. The Effect of Some Physical and Chemical Parameters on Regrowth of Aeromonas Bacterium and Heterotrophic Bacteria in Isfahan Drinking Water System

    Directory of Open Access Journals (Sweden)

    Sina Dobaradaran

    2006-03-01

    Full Text Available Aeromonas is one the gram – negative , non spor – formating rod shaping , facultatively anaerobic and opportunistic bactria that can cause systematic infections, leision and diarrhoea in human. Fairly high bactrial population in distribution system is not only of concern because of affecting consumer health but also it makes it difficult to enumerate coliform bacterium indicator. So, the relationships between aeromonas and heterotrophic bacteria growth with pH, temperature, turbidity, free residual cholornie and DO were determined in this study. ADA- V media was used in presumptive stage to count aeromonas bacteria for the first time in Iran on the basis of 1605 EPA (2001 method and used oxidase tests, trehalose fermentation and indol test in confirmative stage. R2A media was used to count HPC bacteria and other factors measured on the basis of standards. The results showed that positive cases of aeromonas bacteria and HPC increase in higher temperature and turbidity and lower pH. In contrast, positive cases of aeromonas bacteria and HPC decrease while free residual cholorine and DO increase. In addition,no positive case of aeromonas was observed in more than 0.2 mg/L concentration of free residual cholorine.

  11. Limnobacter litoralis sp. nov., a thiosulfate-oxidizing, heterotrophic bacterium isolated from a volcanic deposit, and emended description of the genus Limnobacter.

    Science.gov (United States)

    Lu, Hongsheng; Sato, Yoshinori; Fujimura, Reiko; Nishizawa, Tomoyasu; Kamijo, Takashi; Ohta, Hiroyuki

    2011-02-01

    A Gram-negative, aerobic, heterotrophic bacterium, designated KP1-19(T), was isolated from a 22-year-old volcanic deposit at a site lacking vegetation on the island of Miyake, Japan. Strain KP1-19(T) was able to use thiosulfate (optimum concentration 10 mM) as an additional energy source. 16S rRNA gene sequence analysis indicated that strain KP1-19(T) was closely related to Limnobacter thiooxidans CS-K2(T) within the class Betaproteobacteria (97.7 % 16S rRNA gene sequence similarity). The cellular fatty acid profile was characteristic of the genus Limnobacter: the major fatty acids (>5 %) were C(16 : 0), C(16 : 1)ω7c and C(18 : 1)ω7c and minor amounts of C(10 : 0) 3-OH were also found. DNA-DNA relatedness between strain KP1-19(T) and L. thiooxidans LMG 19593(T) was 18 %. Therefore, strain KP1-19(T) represents a novel species, for which the name Limnobacter litoralis sp. nov. is proposed. The type strain is KP1-19(T) (=LMG 24869(T) =NBRC 105857(T) =CIP 109929(T)).

  12. PO43- dependence of the tolerance of autotrophic and heterotrophic biofilm communities to copper and diuron.

    Science.gov (United States)

    Tlili, Ahmed; Bérard, Annette; Roulier, Jean-Louis; Volat, Bernadette; Montuelle, Bernard

    2010-06-10

    Pollution-induced community tolerance (PICT) concept is based on the assumption that the toxicant exerts selection pressure on the biological communities when exposure reaches a critical level for a sufficient period of time and therefore sensitive species are eliminated. However, induced tolerance of microbial biofilm communities cannot be attributed solely to the presence of toxicants in rivers but also to various environmental factors, such as amount of nutrients. An experimental study was undertaken to highlight the potential impact of a phosphorus gradient on the sensitivity of periphytic microbial community to Cu and diuron. Biofilms were exposed to real-world levels of chronic environmental contamination of toxicants with a phosphorus gradient. Biofilm sensitivity to Cu and diuron was assessed by performing short-term inhibition tests based on photosynthetic efficiency to target photoautotrophs, extracellular enzyme activity (beta-glucosidase and leucine-aminopeptidase) and substrate-induced respiration activity to target heterotrophs. The impact of P-gradient associated to pollution was evaluated by measuring pesticide concentrations in biofilms, biomass parameters (chla, AFDW), bacterial cell density, photosynthetic efficiency and community structure (using 18S and 16S rDNA gene analysis to target eukaryotes and DGGE and HPLC pigment analysis to target bacteria and photoautotrophs). The obtained results show that depending on the studied toxicant and the used structural or functional parameter, the effect of the phosphorus gradient was variable. This highlights the importance of using a range of parameters that target all the biological communities in the biofilm. The PICT method can be regarded as a good tool for assessing anthropogenic environmental contamination, but it is necessary to dissociate the real impact of toxicants from environmental factors.

  13. Are variations in heterotrophic soil respiration related to changes in substrate availability and microbial biomass carbon in the subtropical forests?

    Science.gov (United States)

    Wei, Hui; Chen, Xiaomei; Xiao, Guoliang; Guenet, Bertrand; Vicca, Sara; Shen, Weijun

    2015-01-01

    Soil temperature and moisture are widely-recognized controlling factors on heterotrophic soil respiration (Rh), although they often explain only a portion of Rh variability. How other soil physicochemical and microbial properties may contribute to Rh variability has been less studied. We conducted field measurements on Rh half-monthly and associated soil properties monthly for two years in four subtropical forests of southern China to assess influences of carbon availability and microbial properties on Rh. Rh in coniferous forest was significantly lower than that in the other three broadleaf species-dominated forests and exhibited obvious seasonal variations in the four forests (P < 0.05). Temperature was the primary factor influencing the seasonal variability of Rh while moisture was not in these humid subtropical forests. The quantity and decomposability of dissolved organic carbon (DOC) were significantly important to Rh variations, but the effect of DOC content on Rh was confounded with temperature, as revealed by partial mantel test. Microbial biomass carbon (MBC) was significantly related to Rh variations across forests during the warm season (P = 0.043). Our results suggest that DOC and MBC may be important when predicting Rh under some conditions, and highlight the complexity by mutual effects of them with environmental factors on Rh variations. PMID:26670822

  14. Heterotrophic bacterial responses to the winter–spring phytoplankton bloom in open waters of the NW Mediterranean

    KAUST Repository

    Gomes, Ana

    2014-12-03

    The response of planktonic heterotrophic prokaryotes to the NW Mediterranean winter–spring offshore phytoplankton bloom was assessed in 3 cruises conducted in March, April–May and September 2009. Bulk measurements of phytoplankton and bacterioplankton biomass and production were complemented with an insight into bacterial physiological structure by single-cell analysis of nucleic acid content [low (LNA) vs. high (HNA)] and membrane integrity (“Live” vs. “Dead” cells). Bacterial production empirical conversion factors (0.82±0.25 SE kg C mol leucine−1) were almost always well below the theoretical value. Major differences in most microbial variables were found among the 3 periods, which varied from extremely high phytoplankton biomass and production during the bloom in March (>1 g C m−2 d−1 primary production) to typically oligotrophic conditions during September stratification (<200 mg C m−2 d−1). In both these periods bacterial production was ~30 mg C m−2 d−1 while very large bacterial production (mean 228, with some stations exceeding 500 mg C m−2 d−1) but low biomass was observed during the April–May post-bloom phase. The contribution of HNA (30–67%) and “Live” cells (47–97%) were temporally opposite in the study periods, with maxima in March and September, respectively. Different relationships were found between physiological structure and bottom-up variables, with HNA bacteria apparently more responsive to phytoplankton only during the bloom, coinciding with larger average cell sizes of LNA bacteria. Moderate phytoplankton–bacterioplankton coupling of biomass and activity was only observed in the bloom and post-bloom phases, while relationships between both compartments were not significant under stratification. With all data pooled, bacteria were only weakly bottom-up controlled. Our analyses show that the biomass and production of planktonic algae and bacteria followed opposite paths in the transition from bloom to

  15. Partitioning soil CO2 fluxes by tree-girdling in a Mediterranean (Pinus pinaster) ecosystem reveals a different response of autotrophic and heterotrophic components to environmental variables and photosynthesis under drought conditions

    Science.gov (United States)

    Matteucci, M.; Cescatti, A.; Gruening, C.; Ballarin, I. G.; Guenther, S.; Magnani, F.; Nali, C.; Lorenzini, G.

    2012-04-01

    The response of ecosystems to environmental factors, such as temperature and rainfall, is crucial to understand the impact of climate change on the terrestrial C cycle. Forest soil respiration represents the main pathway by which photosynthetically assimilated C is released to atmosphere; its intensity depends not only on soil environmental conditions, but also on the availability of organic substrates respired by roots and microorganisms. Several techniques have been applied to partition the autotrophic and heterotrophic components of soil respiration in boreal and temperate forests; there is a general lack of information, on the contrary, on the dynamics of soil CO2 efflux in Mediterranean ecosystems. The IPCC A1B scenario highlighted the importance of the Mediterranean area since it is expected to experience a temperature increase (from 2.2 °C to 5.1 °C) and a rainfall reduction ranging from -4 to -27% on annual basis. We used the tree-girdling technique together with periodic chamber-based measurements to study the partitioning of total soil respiration (Rs) into its autotrophic (Ra) and heterotrophic (Rh) components in a 60-year old forest in Central Italy (San Rossore) dominated by Pinus pinaster. This technique has been extensively used to block the flux of photosynthates from leaves to roots, thus stopping the autotrophic root respiration in the soil. We found that two weeks after the treatment soil respiration in the girdled plots decreased by 29% and remained stable over the period of analysis, suggesting that Rh dominates total soil respiration. The anomalous low rainfall regimen of May to October 2011 (102 mm cumulated rain) associated with average air temperatures (with a mean value of 19,6 °C over the period) gave us the opportunity to investigate the decoupled response of soil respiration to water and temperature. Time series analysis performed under this severe drought conditions showed overall low values of soil respiration with three clear

  16. Trimethylamine and trimethylamine N-oxide are supplementary energy sources for a marine heterotrophic bacterium: implications for marine carbon and nitrogen cycling.

    Science.gov (United States)

    Lidbury, Ian D E A; Murrell, J Colin; Chen, Yin

    2015-03-01

    Bacteria of the marine Roseobacter clade are characterised by their ability to utilise a wide range of organic and inorganic compounds to support growth. Trimethylamine (TMA) and trimethylamine N-oxide (TMAO) are methylated amines (MA) and form part of the dissolved organic nitrogen pool, the second largest source of nitrogen after N2 gas, in the oceans. We investigated if the marine heterotrophic bacterium, Ruegeria pomeroyi DSS-3, could utilise TMA and TMAO as a supplementary energy source and whether this trait had any beneficial effect on growth. In R. pomeroyi, catabolism of TMA and TMAO resulted in the production of intracellular ATP which in turn helped to enhance growth rate and growth yield as well as enhancing cell survival during prolonged energy starvation. Furthermore, the simultaneous use of two different exogenous energy sources led to a greater enhancement of chemoorganoheterotrophic growth. The use of TMA and TMAO primarily as an energy source resulted in the remineralisation of nitrogen in the form of ammonium, which could cross feed into another bacterium. This study provides greater insight into the microbial metabolism of MAs in the marine environment and how it may affect both nutrient flow within marine surface waters and the flux of these climatically important compounds into the atmosphere.

  17. Accumulation of fatty acids in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoAcarboxylase, temperature, and co-immobilization with Azospirillum brasilense [corrected].

    Science.gov (United States)

    Leyva, Luis A; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E

    2014-10-01

    The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae.

  18. Accumulation fatty acids of in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoA carboxylase, temperature, and co-immobilization with Azospirillum brasilense

    Science.gov (United States)

    Leyva, Luis A.; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E.

    2014-10-01

    The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae.

  19. Concurrent and lagged impacts of an anomalously warm year on autotrophic and heterotrophic components of soil respiration: a deconvolution analysis.

    Science.gov (United States)

    Zhou, Xuhui; Luo, Yiqi; Gao, Chao; Verburg, Paul S J; Arnone, John A; Darrouzet-Nardi, Anthony; Schimel, David S

    2010-07-01

    *Partitioning soil respiration into autotrophic (R(A)) and heterotrophic (R(H)) components is critical for understanding their differential responses to climate warming. *Here, we used a deconvolution analysis to partition soil respiration in a pulse warming experiment. We first conducted a sensitivity analysis to determine which parameters can be identified by soil respiration data. A Markov chain Monte Carlo technique was then used to optimize those identifiable parameters in a terrestrial ecosystem model. Finally, the optimized parameters were employed to quantify R(A) and R(H) in a forward analysis. *Our results displayed that more than one-half of parameters were constrained by daily soil respiration data. The optimized model simulation showed that warming stimulated R(H) and had little effect on R(A) in the first 2 months, but decreased both R(H) and R(A) during the remainder of the treatment and post-treatment years. Clipping of above-ground biomass stimulated the warming effect on R(H) but not on R(A). Overall, warming decreased R(A) and R(H) significantly, by 28.9% and 24.9%, respectively, during the treatment year and by 27.3% and 33.3%, respectively, during the post-treatment year, largely as a result of decreased canopy greenness and biomass. *Lagged effects of climate anomalies on soil respiration and its components are important in assessing terrestrial carbon cycle feedbacks to climate warming.

  20. Simultaneous biological nutrient removal: evaluation of autotrophic denitrification, heterotrophic nitrification, and biological phosphorus removal in full-scale systems.

    Science.gov (United States)

    Littleton, Helen X; Daigger, Glen T; Strom, Peter F; Cowan, Robert A

    2003-01-01

    Simultaneous biological nutrient removal (SBNR) is the biological removal of nitrogen and phosphorus in excess of that required for biomass synthesis in a biological wastewater treatment system without defined anaerobic or anoxic zones. Evidence is growing that significant SBNR can occur in many systems, including the aerobic zone of systems already configured for biological nutrient removal. Although SBNR systems offer several potential advantages, they cannot be fully realized until the mechanisms responsible for SBNR are better understood. Consequently, a research program was initiated with the basic hypothesis that three mechanisms might be responsible for SBNR: the reactor macroenvironment, the floc microenvironment, and novel microorganisms. Previously, the nutrient removal capabilities of seven full-scale, staged, closed-loop bioreactors known as Orbal oxidation ditches were evaluated. Chemical analysis and microbiological observations suggested that SBNR occurred in these systems. Three of these plants were further examined in this research to evaluate the importance of novel microorganisms, especially for nitrogen removal. A screening tool was developed to determine the relative significance of the activities of microorganisms capable of autotrophic denitrification and heterotrophic nitrification-aerobic denitrification in biological nutrient removal systems. The results indicated that novel microorganisms were not substantial contributors to SBNR in the plants studied. Phosphorus metabolism (anaerobic release, aerobic uptake) was also tested in one of the plants. Activity within the mixed liquor that was consistent with current theories for phosphorus-accumulating organisms (PAOs) was observed. Along with other observations, this suggests the presence of PAOs in the facilities studied.

  1. The Robin, Erithacus Rubecula (Passeriformes, Turdidae, as a Component of Heterotrophic Consortia of Forest Cenoses, Northeast Ukraine. Part 2

    Directory of Open Access Journals (Sweden)

    Chaplygina A. B.

    2016-12-01

    Full Text Available The role of the robin as a determinant of heterotrophic consortia is considered. The robin is a consort of determinants of autotrophic consortia, which core is represented mostly by dominating species of deciduous trees (Quercus robur Linnaeus, 1753, Tilia cordata Miller, 1768, Acer platanoides Linnaeus, 1753, Acer campestre Linnaeus, 1753, and also by sedges (Carex sp. and grasses (Poaceae, connected with the determinants by fabric links. The robin also belongs to the concentr of the second and higher orders as a component of forest biogeocenoses and it is also the main determinant in species composition of the insects inhabiting bird nests. As a result of the taxonomic analysis of invertebrates in the robin nests, it has been found out that the most numerous class was Insecta (9 orders and 27 families, with the dominance of Coleoptera (30.7 %. The nidicolous fauna of the robin (38 species was dominated by zoophages along with parasites and hematophages such as Hippoboscidae (46.4 %. The percentage of phytophages and saprophages among the invertebrate nest inhabitants was somewhat less (21 % each, then followed necrophages (12 %. Zoophages and parasites also dominated according to the number of objects in the nests (42 %; n = 150, the less was the portion of phytophages (34 %, saprophages (18 %, and necrophages (6 %. The highest number of species and objects of zoophages was recorded for climax and mature biocenoses (oak forests in NNP “HL” and pine cenoses in NNP “H””.

  2. Formaldehyde as a carbon and electron shuttle between autotroph and heterotroph populations in acidic hydrothermal vents of Norris Geyser Basin, Yellowstone National Park

    Energy Technology Data Exchange (ETDEWEB)

    Moran, James J.; Whitmore, Laura M.; Isern, Nancy G.; Romine, Margaret F.; Riha, Krystin M.; Inskeep, William P.; Kreuzer, Helen W.

    2016-03-19

    The Norris Geyser Basin in Yellowstone National Park contains a large number of hydrothermal systems, which host microbial populations supported by primary productivity associated with a suite of chemolithotrophic metabolisms. We demonstrate that Metallosphaera yellowstonesis MK1, a facultative autotrophic archaeon isolated from a hyperthermal acidic hydrous ferric oxide (HFO) spring in Norris Geyser Basin, excretes formaldehyde during autotrophic growth. To determine the fate of formaldehyde in this low organic carbon environment, we incubated native microbial mat (containing M. yellowstonensis) from a HFO spring with 13C-formaldehyde. Isotopic analysis of incubation-derived CO2 and biomass showed that formaldehyde was both oxidized and assimilated by members of the community. Autotrophy, formaldehyde oxidation, and formaldehyde assimilation displayed different sensitivities to chemical inhibitors, suggesting that distinct sub-populations in the mat selectively perform these functions. Our results demonstrate that electrons originally resulting from iron oxidation can energetically fuel autotrophic carbon fixation and associated formaldehyde excretion, and that formaldehyde is both oxidized and assimilated by different organisms within the native microbial community. Thus, formaldehyde can effectively act as a carbon and electron shuttle connecting the autotrophic, iron oxidizing members with associated heterotrophic members in the HFO community.

  3. Heterotrophic bacteria in soils of Larsemann Oasis of East Antarctica

    Science.gov (United States)

    Churilin, Nikita; Soina, Vera

    2015-04-01

    The study of diversity and functional state of microorganisms in subsurface rocks layers, their participation in the biochemical weathering and formation of organic horizons of soils is important for understanding ecology and microorganisms in Antarctic soils. The study of cultured forms of microorganisms and their potential viability is still relevant to characterize the physiological state, biological activity and resilience of microorganisms involved in the initial soil formation. Improvement of isolation techniques of viable bacteria from the extreme habitats has a particular importance for rising the efficiency of environmental monitoring. The aim of the study was to investigate the viable heterotrophic bacteria involved in the formation of soils from wet valleys Larsemann Oasis, which is one of the warmest ice-free space of East Antarctica. Soil samples were taken from the intermountain humid valleys, where silt-gravelly substrates formed moss, algae, lichen cover. We used nutrient solutions (trypticase soy, R2A and glucose-peptone) to isolate cultured bacteria and study their morphological types in the light microscope. The total number of microorganisms was determined by fluorescent microscopy with acridine orange. SEM was used for morphological studies of bacterial communities in situ. To activate the growth processes we added into nutrient solutions various regulatory metabolites that have dose-dependence and operate at the community level. Physiological and functional conditions were determined by the duration of the lag phase and specific growth rate of bacterial communities in nutrient solutions containing various organic substrates. Soils form under protection of «stone pavement» and organisms leave the surface, so the forming organo-mineral horizon occurs inside of rock, thus the microprofile can form on both sides of the organic horizons. UV radiation, lack of moisture and strong wind are main limiting factors for microorganisms' growth in

  4. Los poliquetos (Annelida: Polychaeta) descritos en el Pacífico mexicano: revisión histórica y lista faunística actualizada

    OpenAIRE

    Hernández-Alcántara, Pablo; Tovar-Hernández, María Ana; Solís-Weiss, Vivianne

    2008-01-01

    An updated checklist of the polychaete species described for the Mexican Pacific and an historic review of their study are presented. The taxonomic list includes nomenclature references, data of the type locality and synonyms based on systematic revisions. In the study area, 313 species of polychaetes and 21 genera have been described, of which 278 species are currently valid. Several descriptions (28%) of the valid species failed to indicate the habitat of the type locality. The remaining 19...

  5. Heterotrophic bacterial production, respiration, and growth efficiency associated with upwelling intensity in the Ulleung Basin, East Sea

    Science.gov (United States)

    Kim, Bomina; Kim, Sung-Han; Kwak, Jung Hyun; Kang, Chang-Keun; Lee, Sang Heon; Hyun, Jung-Ho

    2017-09-01

    We investigated bacterial production (BP) and respiration (BR), as well as the physico-chemical properties of the water column, to elucidate the effect of upwelling on heterotrophic bacterial metabolic activities and growth efficiency (BGE) in July 2012 and May 2013 in the Ulleung Basin (UB), East/Japan Sea. The upwelled conditions were characterized by higher chlorophyll-a (Chl-a) concentrations resulting from the upward shift of the nitracline compared to that of the non-upwelled condition. Analyses of the size fractions of Chl-a and pigment composition revealed that large size phytoplankton (> 20 μm), mainly consisting of diatoms, appeared to be the major phytoplankton component. BP and BR were significantly correlated with Chl-a (P 0.05). These results suggest that bacterial metabolic activities are stimulated by the availability of organic resources enhanced by upwelling in the UB. Further statistical analysis showed that the difference in BP and BGE with variations in upwelling intensity were significant (P = 0.018 for BP, P = 0.035 for BGE), but the difference in BR was not significant (P = 0.321). These results suggest that metabolic energy is partitioned more for BP under a strong upwelling condition, i.e. high nutrient and Chl-a conditions. In contrast, the energy generated via respiration was partitioned more for maintaining metabolism rather than for biomass production under weakly or non-upwelled conditions, i.e. stratified and low Chl-a conditions. Overall, our results suggest that any changes in upwelling intensity would significantly affect the carbon cycle associated with the fate of primary production, and the role of the microbial loop in the UB where changes in the intensity and frequency of upwelling associated with climatic changes are in progress.

  6. Natural heterotrophic feeding by a temperate octocoral with symbiotic zooxanthellae: a contribution to understanding the mechanisms of die-off events

    Science.gov (United States)

    Coma, Rafel; Llorente-Llurba, Eduard; Serrano, Eduard; Gili, Josep-Maria; Ribes, Marta

    2015-06-01

    Octocorals are among the most emblematic and representative organisms of sublittoral communities in both tropical and temperate seas. Eunicella singularis is the most abundant gorgonian in shallow waters and the only gorgonian with symbiotic zooxanthellae in the Mediterranean Sea. We studied the natural diet and prey capture rate of this species over an annual cycle and characterized prey digestion time over the natural temperature regime. The species captured zooplankton prey between 40 and 920 µm. A mean content of 0.14 ± 0.02 prey polyp-1 was observed throughout the year. The strong pattern of decrease in digestion time with temperature increase (from 25 h at 13 °C to 8 h at 21 °C) allowed us to estimate that the prey capture rate was 0.017 ± 0.002 prey polyp-1 h-1 (mean ± SE); the ingestion rate exhibited a seasonal pattern with higher values in spring (0.007 µg C polyp-1 h-1). Feeding on zooplankton had a low contribution to the respiratory expenses of E. singularis except in early spring. Then, heterotrophic nutrition in the natural environment seems unable to meet basal metabolic requirements, especially in summer and fall. This result, in conjunction with the documented collapse of photosynthetic capacity above a warm temperature threshold, indicates the occurrence of a resource acquisition limitation that may play a role in the repeated summer die-off events of the species.

  7. The impact of fossil data on annelid phylogeny inferred from discrete morphological characters.

    Science.gov (United States)

    Parry, Luke A; Edgecombe, Gregory D; Eibye-Jacobsen, Danny; Vinther, Jakob

    2016-08-31

    As a result of their plastic body plan, the relationships of the annelid worms and even the taxonomic makeup of the phylum have long been contentious. Morphological cladistic analyses have typically recovered a monophyletic Polychaeta, with the simple-bodied forms assigned to an early-diverging clade or grade. This is in stark contrast to molecular trees, in which polychaetes are paraphyletic and include clitellates, echiurans and sipunculans. Cambrian stem group annelid body fossils are complex-bodied polychaetes that possess well-developed parapodia and paired head appendages (palps), suggesting that the root of annelids is misplaced in morphological trees. We present a reinvestigation of the morphology of key fossil taxa and include them in a comprehensive phylogenetic analysis of annelids. Analyses using probabilistic methods and both equal- and implied-weights parsimony recover paraphyletic polychaetes and support the conclusion that echiurans and clitellates are derived polychaetes. Morphological trees including fossils depict two main clades of crown-group annelids that are similar, but not identical, to Errantia and Sedentaria, the fundamental groupings in transcriptomic analyses. Removing fossils yields trees that are often less resolved and/or root the tree in greater conflict with molecular topologies. While there are many topological similarities between the analyses herein and recent phylogenomic hypotheses, differences include the exclusion of Sipuncula from Annelida and the taxa forming the deepest crown-group divergences. © 2016 The Authors.

  8. Influence of an oyster reef on development of the microbial heterotrophic community of an estuarine biofilm.

    Science.gov (United States)

    Nocker, Andreas; Lepo, Joe E; Snyder, Richard A

    2004-11-01

    We characterized microbial biofilm communities developed over two very closely located but distinct benthic habitats in the Pensacola Bay estuary using two complementary cultivation-independent molecular techniques. Biofilms were grown for 7 days on glass slides held in racks 10 to 15 cm over an oyster reef and an adjacent muddy sand bottom. Total biomass and optical densities of dried biofilms showed dramatic differences for oyster reef versus non-oyster reef biofilms. This study assessed whether the observed spatial variation was reflected in the heterotrophic prokaryotic species composition. Genomic biofilm DNA from both locations was isolated and served as a template to amplify 16S rRNA genes with universal eubacterial primers. Fluorescently labeled PCR products were analyzed by terminal restriction fragment length polymorphism, creating a genetic fingerprint of the composition of the microbial communities. Unlabeled PCR products were cloned in order to construct a clone library of 16S rRNA genes. Amplified ribosomal DNA restriction analysis was used to screen and define ribotypes. Partial sequences from unique ribotypes were compared with existing database entries to identify species and to construct phylogenetic trees representative of community structures. A pronounced difference in species richness and evenness was observed at the two sites. The biofilm community structure from the oyster reef setting had greater evenness and species richness than the one from the muddy sand bottom. The vast majority of the bacteria in the oyster reef biofilm were related to members of the gamma- and delta-subdivisions of Proteobacteria, the Cytophaga-Flavobacterium -Bacteroides cluster, and the phyla Planctomyces and Holophaga-Acidobacterium. The same groups were also present in the biofilm harvested at the muddy sand bottom, with the difference that nearly half of the community consisted of representatives of the Planctomyces phylum. Total species richness was estimated

  9. Application of Radiotracer Methodology for Understanding the Influence of Geochemical Fractionation on Metal Bioavailability in Estuarine Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, N. S.; Baumann, Z. [School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY (United States)

    2013-07-15

    To evaluate the extent to which contaminated sediments could introduce metals into marine food chains, gamma emitting radioisotopes of arsenic, cadmium and chromium were used to study their geochemical fractionation in estuarine sediments and bioavailability to deposit feeding polychaetes. Radioisotopes were added to sediments directly or via planktonic debris and were then fractionated with a sequential extraction scheme after aging for up to 90 days. The assimilation of ingested metals was positively related to their partitioning in the two most readily extractable (labile) sediment fractions and negatively related to refractory organic fractions, oxides, and pyrite. In comparison to uptake from ingested sediment, metal uptake from pore water was negligible. A metal bioaccumulation model, modified to consider their geochemical fractionation, was found to quantitatively predict metal concentrations in benthic polychaetes better than total metal concentrations in sediment. Metals need to desorb from ingested particles into gut fluid within the polychaete gut before they can be assimilated. (author)

  10. Sewage impact on the composition and distribution of Polychaeta associated to intertidal mussel beds of the Mar del Plata rocky shore, Argentina

    Directory of Open Access Journals (Sweden)

    Elías Rodolfo

    2003-01-01

    Full Text Available The polychaete composition and distribution within mussel beds were studied in order to assess organic pollution due to domestic sewage in a rocky shore of Mar del Plata (Argentina during 1997. Four stations and a control site were randomly sampled around the local effluent. Quantitative data on polychaetes, as well as sediment accumulated among mussels and its organic carbon content were measured. Polychaete distribution patterns are related to the organic matter gradient, being Capitella cf. capitata, Neanthes succinea (Frey & Leuckart, 1847 and Boccardia polybranchia (Haswell, 1885 the dominant indicator species close to the effluent. At medial distances, the cirratulids Caulleriella alata (Southern, 1914 and Cirratulus cirratus (Müller, 1776 are very important in abundance. The syllids Syllis prolixa Ehlers, 1901 and S. gracilis Grube, 1840 are distributed along the study area, but dominate at the medial stations and at the control site. The orbiniid Protoariciella uncinata Hartmann-Schröder, 1962 is subdominant at the control station.

  11. Genome-Scale Metabolic Model for the Green Alga Chlorella vulgaris UTEX 395 Accurately Predicts Phenotypes under Autotrophic, Heterotrophic, and Mixotrophic Growth Conditions1

    Science.gov (United States)

    Zuñiga, Cristal; Li, Chien-Ting; Zielinski, Daniel C.; Guarnieri, Michael T.; Antoniewicz, Maciek R.; Zengler, Karsten

    2016-01-01

    The green microalga Chlorella vulgaris has been widely recognized as a promising candidate for biofuel production due to its ability to store high lipid content and its natural metabolic versatility. Compartmentalized genome-scale metabolic models constructed from genome sequences enable quantitative insight into the transport and metabolism of compounds within a target organism. These metabolic models have long been utilized to generate optimized design strategies for an improved production process. Here, we describe the reconstruction, validation, and application of a genome-scale metabolic model for C. vulgaris UTEX 395, iCZ843. The reconstruction represents the most comprehensive model for any eukaryotic photosynthetic organism to date, based on the genome size and number of genes in the reconstruction. The highly curated model accurately predicts phenotypes under photoautotrophic, heterotrophic, and mixotrophic conditions. The model was validated against experimental data and lays the foundation for model-driven strain design and medium alteration to improve yield. Calculated flux distributions under different trophic conditions show that a number of key pathways are affected by nitrogen starvation conditions, including central carbon metabolism and amino acid, nucleotide, and pigment biosynthetic pathways. Furthermore, model prediction of growth rates under various medium compositions and subsequent experimental validation showed an increased growth rate with the addition of tryptophan and methionine. PMID:27372244

  12. Acidithrix ferrooxidans gen. nov., sp. nov.; a filamentous and obligately heterotrophic, acidophilic member of the Actinobacteria that catalyzes dissimilatory oxido-reduction of iron.

    Science.gov (United States)

    Jones, Rose M; Johnson, D Barrie

    2015-01-01

    A novel acidophilic member of the phylum Actinobacteria was isolated from an acidic stream draining an abandoned copper mine in north Wales. The isolate (PY-F3) was demonstrated to be a heterotroph that catalyzed the oxidation of ferrous iron (but not of sulfur or hydrogen) under aerobic conditions, and the reduction of ferric iron under micro-aerobic and anaerobic conditions. PY-F3 formed long entangled filaments of cells (>50 μm long) during active growth phases, though these degenerated into smaller fragments and single cells in late stationary phase. Although isolate PY-F3 was not observed to grow below pH 2.0 and 10 °C, harvested biomass was found to oxidize ferrous iron at relatively fast rates at pH 1.5 and 5 °C. Phylogenetic analysis, based on comparisons of 16S rRNA gene sequences, showed that isolate PY-F3 has 91-93% gene similarity to those of the four classified genera and species of acidophilic Actinobacteria, and therefore is a representative of a novel genus. The binomial Acidithrix ferrooxidans is proposed for this new species, with PY-F3 as the designated type strain (=DSM 28176(T), =JCM 19728(T)). Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  13. Genome-Scale Metabolic Model for the Green Alga Chlorella vulgaris UTEX 395 Accurately Predicts Phenotypes under Autotrophic, Heterotrophic, and Mixotrophic Growth Conditions.

    Science.gov (United States)

    Zuñiga, Cristal; Li, Chien-Ting; Huelsman, Tyler; Levering, Jennifer; Zielinski, Daniel C; McConnell, Brian O; Long, Christopher P; Knoshaug, Eric P; Guarnieri, Michael T; Antoniewicz, Maciek R; Betenbaugh, Michael J; Zengler, Karsten

    2016-09-01

    The green microalga Chlorella vulgaris has been widely recognized as a promising candidate for biofuel production due to its ability to store high lipid content and its natural metabolic versatility. Compartmentalized genome-scale metabolic models constructed from genome sequences enable quantitative insight into the transport and metabolism of compounds within a target organism. These metabolic models have long been utilized to generate optimized design strategies for an improved production process. Here, we describe the reconstruction, validation, and application of a genome-scale metabolic model for C. vulgaris UTEX 395, iCZ843. The reconstruction represents the most comprehensive model for any eukaryotic photosynthetic organism to date, based on the genome size and number of genes in the reconstruction. The highly curated model accurately predicts phenotypes under photoautotrophic, heterotrophic, and mixotrophic conditions. The model was validated against experimental data and lays the foundation for model-driven strain design and medium alteration to improve yield. Calculated flux distributions under different trophic conditions show that a number of key pathways are affected by nitrogen starvation conditions, including central carbon metabolism and amino acid, nucleotide, and pigment biosynthetic pathways. Furthermore, model prediction of growth rates under various medium compositions and subsequent experimental validation showed an increased growth rate with the addition of tryptophan and methionine. © 2016 American Society of Plant Biologists. All rights reserved.

  14. Simultaneous removal of carbon and nitrogen by mycelial pellets of a heterotrophic nitrifying fungus-Penicillium sp. L1.

    Science.gov (United States)

    Liu, Yuxiang; Hu, Tingting; Zhao, Jing; Lv, Yongkang; Ren, Ruipeng

    2017-02-01

    A novel heterotrophic nitrifying fungus, defined as Penicillium sp. L1, can form mycelial pellets in liquid medium in this study. The effects of inoculation method, C/N ratio, initial pH, and temperature were gradually evaluated to improve the simultaneous removal of total nitrogen (TN) and chemical oxygen demand (COD) in wastewater by Penicillium sp. L1. Results showed that compared with spore inoculation, 48 h pellet inoculum could significantly increase the pellet size (from about 1.5 mm to 3.2 mm) and improve the removal capability, particularly for COD removal (from less than 50-86.20%). The removal efficiencies of TN and COD reached 98.38% (from 136.01 mg/L to 2.20 mg/L) and 92.40% (from 10,720 mg/L to 815 mg/L) under the following conditions: C/N 36, pH 3, 30°C, and inoculation with 48 h pellets. The pellet diameter reached 4.8 mm after 4-day cultivation. In this case, Penicillium sp. L1 removed TN from 415.93 mg/L to 43.39 mg/L, as well as COD from 29,533 mg/L to 8850 mg/L. Overall, the results indicated that the pellet size was closely related to the pollutant-removal ability of Penicillium sp. L1. Furthermore, mycelial pellets (4.8 mm, dead) only adsorbed 38.08% TN (from 125.45 mg/L to 77.78 mg/L), which indicated that adsorption did not play a major role in the nitrogen-removal process. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  15. Lack of P-limitation of phytoplankton and heterotrophic prokaryotes in surface waters of three anticyclonic eddies in the stratified Mediterranean Sea

    Science.gov (United States)

    Tanaka, T.; Thingstad, T. F.; Christaki, U.; Colombet, J.; Cornet-Barthaux, V.; Courties, C.; Grattepanche, J.-D.; Lagaria, A.; Nedoma, J.; Oriol, L.; Psarra, S.; Pujo-Pay, M.; van Wambeke, F.

    2011-02-01

    We investigated the identity of the limiting nutrient of the pelagic microbial food web in the Mediterranean Sea using nutrient manipulated microcosms during summer 2008. Experiments were carried out with surface waters at the center of anticyclonic eddies in the Western Basin, the Ionian Basin, and the Levantine Basin. In situ, the ratio of N to P was always higher in both dissolved and particulate organic fractions compared to the Redfield ratio, suggesting a relative P-starvation. In each experiment, four different treatments in triplicates (addition of ammonium, phosphate, a combination of both, and the unamended control) were employed and chemical and biological parameters monitored throughout a 3-4 day incubation. Temporal changes of turnover time of phosphate and ATP, and alkaline phosphatase activity during the incubation suggested that the phytoplankton and heterotrophic prokaryotes (Hprok) communities were not P-limited at the sites. Furthermore, statistical comparison among treatments at the end of the incubation did not support a hypothesis of P-limitation at the three study sites. In contrast, primary production was consistently limited by N, and Hprok growth was not limited by N nor P in the Western Basin, but N-limited in the Ionian Basin, and N and P co-limited in the Levantine Basin. Our results demonstrated the gap between biogeochemical features (an apparent P-starved status) and biological responses (no apparent P-limitation). We question the general notion that Mediterranean surface waters are limited by P alone during the stratified period.

  16. Relative contributions of Vibrio polysaccharide and quorum sensing to the resistance of Vibrio cholerae to predation by heterotrophic protists.

    Directory of Open Access Journals (Sweden)

    Shuyang Sun

    Full Text Available Protozoan grazing is a major mortality factor faced by bacteria in the environment. Vibrio cholerae, the causative agent of the disease cholera, is a natural inhabitant of aquatic ecosystems, and its survival depends on its ability to respond to stresses, such as predation by heterotrophic protists. Previous results show that grazing pressure induces biofilm formation and enhances a smooth to rugose morphotypic shift, due to increased expression of Vibrio polysaccharide (VPS. In addition to negatively controlling vps genes, the global quorum sensing (QS regulator, HapR, plays a role in grazing resistance as the ΔhapR strain is efficiently consumed while the wild type (WT is not. Here, the relative and combined contributions of VPS and QS to grazing resistance were investigated by exposing VPS and HapR mutants and double mutants in VPS and HapR encoding genes at different phases of biofilm development to amoeboid and flagellate grazers. Data show that the WT biofilms were grazing resistant, the VPS mutants were less resistant than the WT strain, but more resistant than the QS mutant strain, and that QS contributes to grazing resistance mainly in mature biofilms. In addition, grazing effects on biofilms of mixed WT and QS mutant strains were investigated. The competitive fitness of each strain in mixed biofilms was determined by CFU and microscopy. Data show that protozoa selectively grazed the QS mutant in mixed biofilms, resulting in changes in the composition of the mixed community. A small proportion of QS mutant cells which comprised 4% of the mixed biofilm biovolume were embedded in grazing resistant WT microcolonies and shielded from predation, indicating the existence of associational protection in mixed biofilms.

  17. Effects of cadmium and lead upon the indigenous heterotrophic microflora in the aqueous environment of the brackish estuary-water of the river Weser

    Energy Technology Data Exchange (ETDEWEB)

    Thormann, D

    1975-01-01

    In agar media (10% salinity) containing Cd or Pb bacterial numbers were progressively reduced at 0.5 to 400 ppM Cd and at 100 to 400 ppM Pb. Only a few bacteria were able to form colonies at the highest concentrations. Lower salinity and low peptone-yeast-extract-concentrations of the medium increased the toxicity of Pb. The appearance of several brown-black pigmented colonies on the plates containing more than 200 ppM Pb was observed, but no dark pigment was noted when the same bacteria were grown in the absence of Pb. Different concentrations of Cd or Pb were added to water samples (as batch cultures) of the Weser Estuary (West Germany). The development of the indigenous microbial population was observed by subsequent counting of the viable heterotrophic bacteria on agar media. Cd was more toxic than Pb; there were differences in the kind of toxicity. The dissolved concentrations of Cd and Pb in the batch cultures were analyzed by atomic absorption. Cd dissolved considerably better than Pb in brackish water. Cd- and Pb-sensitive bacteria were isolated by a replica plating technique to carry out subsequent experiments on the microbial uptake of heavy metals. The most sensitive bacteria were growth-inhibited at 0.1 ppM Cd and Pb. Arthrobacter marinus is mentioned.

  18. Short and long term biosorption of silica-coated iron oxide nanoparticles in heterotrophic biofilms

    International Nuclear Information System (INIS)

    Herrling, Maria P.; Lackner, Susanne; Tatti, Oleg; Guthausen, Gisela; Delay, Markus; Franzreb, Matthias; Horn, Harald

    2016-01-01

    The increased application of engineered nanoparticles (ENP) in industrial processes and consumer products has raised concerns about their impact on health and environmental safety. When ENP enter the global water cycle by e.g. wastewater streams, wastewater treatment plants (WWTP) represent potential sinks for ENP. During biological WWT, the attachment of ENP to biofilms is responsible for the desired removal of ENP from the water phase avoiding their release into the aquatic environment. However, the fundamental mechanisms guiding the interactions between ENP and biofilms are not yet fully understood. Therefore, this study investigates the behavior and biosorption of inorganic ENP, here magnetic iron oxide nanoparticles coated with silica (scFe_3O_4-NP), with heterotrophic biofilms at different time scales. Their magnetic properties enable to follow scFe_3O_4-NP in the biofilm system by a magnetic susceptibility balance and magnetic resonance imaging. Biofilms were exposed to scFe_3O_4-NP at short contact times (5 min) in flow cells and complementary, scFe_3O_4-NP were introduced into a moving bed biofilm reactor (MBBR) to be observed for 27 d. Mass balances revealed that scFe_3O_4-NP sorbed to the biofilm within a few minutes, but that the total biosorption was rather low (3.2 μg Fe/mg TSS). scFe_3O_4-NP mainly sorbed to the biofilm surface inducing the detachment of outer biofilm parts starting after an exposure time of 3 h in the MBBR. The biosorption depended on the exposure concentration of scFe_3O_4-NP, but less on the contact time. Most scFe_3O_4-NP exited the flow cell (up to 65%) and the MBBR (57%) via the effluent. This effect was favored by the stabilization of scFe_3O_4-NP in the bulk liquid by organic matter leading to a low retention capacity of the MBBR system. The results contribute to improve our understanding about the fate of ENP in environmental and in technical biofilm systems and give indications for future investigations needed

  19. Seasonal and spatial patterns of heterotrophic bacterial production, respiration, and biomass in the subarctic NE Pacific

    Science.gov (United States)

    Sherry, Nelson D.; Boyd, Philip W.; Sugimoto, Kugako; Harrison, Paul J.

    1999-11-01

    Heterotrophic bacterial biomass, production, and respiration rates were measured during winter, spring, and summer in the subarctic NE Pacific from September 1995 to June 1997. Sampling took place on six cruises at five hydrographic stations along the east/west line-P transect from slope waters at P4 (1200 m depth) to the open-ocean waters at Ocean Station Papa (OSP) (4250 m depth). Interannual variability was small relative to seasonal and spatial variability. Biomass, derived from cell counts (assuming 20 fg C cell -1), was ca. 12 μg C l -1 in the winter and increased to 20-35 μg C l -1 in the spring and summer all along line-P. Bacterial production from [ 3H]-thymidine and [ 14C]-leucine incorporation rates was lowest in the winter (ca. 0.5 μg C l -1 d -1) with little spatial variability. Production increased 10-fold in spring at P4 (to ca. 4.5 μg C l -1 d -1). In contrast, only a 2-fold increase in bacterial production was observed over this period at the more oceanic stations. Rates of production in late summer were highest over the annual cycle at all stations ranging from ca. 6 at P4 to ca. 2 μg C l -1 d -1 at OSP. Bacterial (rates increased >10-fold to ca. 100 μg C l -1 d -1 at P4 in the summer, but, interestingly, did not increase from spring to summer at the more oceanic stations. Thus bacterial growth efficiency, defined as production/(production+respiration), decreased in the spring westwards from the slope waters (P4) to the open-ocean (OSP), but increased westwards in the summer. Bacterial production was highly correlated with temperature at OSP ( r2=0.88) and less so at P4 ( r2=0.50). The observed temporal and spatial trends presented in this study suggest that seasonal changes in bacterial biomass were greatly affected by changes in loss processes, that bacterial biomass is regulated by different processes than bacterial production, and that bacterial production alone, without respiration measurements, is not a robust proxy for bacterial

  20. Dynamics and controls of heterotrophic prokaryotic production in the western tropical South Pacific Ocean: links with diazotrophic and photosynthetic activity

    Science.gov (United States)

    Van Wambeke, France; Gimenez, Audrey; Duhamel, Solange; Dupouy, Cécile; Lefevre, Dominique; Pujo-Pay, Mireille; Moutin, Thierry

    2018-05-01

    Heterotrophic prokaryotic production (BP) was studied in the western tropical South Pacific (WTSP) using the leucine technique, revealing spatial and temporal variability within the region. Integrated over the euphotic zone, BP ranged from 58 to 120 mg C m-2 d-1 within the Melanesian Archipelago, and from 31 to 50 mg C m-2 d-1 within the western subtropical gyre. The collapse of a bloom was followed during 6 days in the south of Vanuatu using a Lagrangian sampling strategy. During this period, rapid evolution was observed in the three main parameters influencing the metabolic state: BP, primary production (PP) and bacterial growth efficiency. With N2 fixation being one of the most important fluxes fueling new production, we explored relationships between BP, PP and N2 fixation rates over the WTSP. The contribution of N2 fixation rates to bacterial nitrogen demand ranged from 3 to 81 %. BP variability was better explained by the variability of N2 fixation rates than by that of PP in surface waters of the Melanesian Archipelago, which were characterized by N-depleted layers and low DIP turnover times (TDIP 100 h), deeper in the Melanesian Archipelago, or within the entire euphotic zone in the subtropical gyre. The bacterial carbon demand to gross primary production ratio ranged from 0.75 to 3.1. These values are discussed in the framework of various assumptions and conversion factors used to estimate this ratio, including the methodological errors, the daily variability of BP, the bacterial growth efficiency and one bias so far not considered: the ability for Prochlorococcus to assimilate leucine in the dark.

  1. Heterotrophic Bioleaching of Sulfur, Iron, and Silicon Impurities from Coal by Fusarium oxysporum FE and Exophiala spinifera FM with Growing and Resting Cells.

    Science.gov (United States)

    Etemadzadeh, Shekoofeh Sadat; Emtiazi, Giti; Etemadifar, Zahra

    2016-06-01

    Coal is the most abundant fossil fuel containing sulfur and other elements which promote environmental pollution after burning. Also the silicon impurities make the transportation of coal expensive. In this research, two isolated fungi from oil contaminated soil with accessory number KF554100 (Fusarium oxysporum FE) and KC925672 (Exophiala spinifera FM) were used for heterotrophic biological leaching of coal. The leaching were detected by FTIR, CHNS, XRF analyzer and compared with iron and sulfate released in the supernatant. The results showed that E. spinifera FM produced more acidic metabolites in growing cells, promoting the iron and sulfate ions removal while resting cells of F. oxysporum FE enhanced the removal of aromatic sulfur. XRF analysis showed that the resting cells of E. spinifera FM proceeded maximum leaching for iron and silicon (48.8, 43.2 %, respectively). CHNS analysis demonstrated that 34.21 % of sulfur leaching was due to the activities of resting cells of F. oxysporum FE. Also F. oxysporum FE removed organic sulfur more than E. spinifera FM in both growing and resting cells. FTIR data showed that both fungi had the ability to remove pyrite and quartz from coal. These data indicated that inoculations of these fungi to the coal are cheap and impurity removals were faster than autotrophic bacteria. Also due to the removal of dibenzothiophene, pyrite, and quartz, we speculated that they are excellent candidates for bioleaching of coal, oil, and gas.

  2. Influence of tryptophan and indole-3-acetic acid on starch accumulation in the synthetic mutualistic Chlorella sorokiniana-Azospirillum brasilense system under heterotrophic conditions.

    Science.gov (United States)

    Palacios, Oskar A; Choix, Francisco J; Bashan, Yoav; de-Bashan, Luz E

    2016-06-01

    This study measured the relations between tryptophan production, the phytohormone indole-3-acetic acid (IAA) and the metabolism and accumulation of starch during synthetic mutualism between the microalgae Chlorella sorokiniana and the microalgae growth-promoting bacteria Azospirillum brasilense, created by co-immobilization in alginate beads. Experiments used two wild-type A. brasilense strains (Cd and Sp6) and an IAA-attenuated mutant (SpM7918) grown under nitrogen-replete and nitrogen-starved conditions tested under dark, heterotrophic and aerobic growth conditions. Under all incubating conditions, C. sorokiniana, but not A. brasilense, produced tryptophan. A significant correlation between IAA-production by A. brasilense and starch accumulation in C. sorokiniana was found, since the IAA-attenuated mutant was not producing increased starch levels. The highest ADP-glucose pyrophosphorylase (AGPase) activity, starch content and glucose uptake were found during the interaction of A. brasilense wild type strains with the microalgae. When the microalgae were grown alone, they produced only small amounts of starch. Supplementation with synthetic IAA to C. sorokiniana grown alone enhanced the above parameters, but only transiently. Activity of α-amylase decreased under nitrogen-replete conditions, but increased under nitrogen-starved conditions. In summary, this study demonstrated that, during synthetic mutualism, the exchange of tryptophan and IAA between the partners is a mechanism that governs several changes in starch metabolism of C. sorokiniana, yielding an increase in starch content. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  3. Short and long term biosorption of silica-coated iron oxide nanoparticles in heterotrophic biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Herrling, Maria P. [Engler-Bunte-Institut, Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 1, 76131 Karlsruhe (Germany); Lackner, Susanne [Engler-Bunte-Institut, Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 1, 76131 Karlsruhe (Germany); Urban Bioengineering for Resource Recovery, Bauhaus-Institute for Infrastructure Solutions, Bauhaus-Universität Weimar, Coudraystraße 7, 99423 Weimar (Germany); Tatti, Oleg [Engler-Bunte-Institut, Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 1, 76131 Karlsruhe (Germany); Guthausen, Gisela [Pro" 2NMR, Institute for Biological Interfaces 4 and Institute for Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology, Adenauerring 20b, 76131 Karlsruhe (Germany); Delay, Markus [Engler-Bunte-Institut, Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 1, 76131 Karlsruhe (Germany); Franzreb, Matthias [Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Horn, Harald, E-mail: harald.horn@kit.edu [Engler-Bunte-Institut, Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 1, 76131 Karlsruhe (Germany); DVGW Research Laboratories for Water Chemistry and Water Technology, Engler-Bunte-Ring 1, 76131 Karlsruhe (Germany)

    2016-02-15

    The increased application of engineered nanoparticles (ENP) in industrial processes and consumer products has raised concerns about their impact on health and environmental safety. When ENP enter the global water cycle by e.g. wastewater streams, wastewater treatment plants (WWTP) represent potential sinks for ENP. During biological WWT, the attachment of ENP to biofilms is responsible for the desired removal of ENP from the water phase avoiding their release into the aquatic environment. However, the fundamental mechanisms guiding the interactions between ENP and biofilms are not yet fully understood. Therefore, this study investigates the behavior and biosorption of inorganic ENP, here magnetic iron oxide nanoparticles coated with silica (scFe{sub 3}O{sub 4}-NP), with heterotrophic biofilms at different time scales. Their magnetic properties enable to follow scFe{sub 3}O{sub 4}-NP in the biofilm system by a magnetic susceptibility balance and magnetic resonance imaging. Biofilms were exposed to scFe{sub 3}O{sub 4}-NP at short contact times (5 min) in flow cells and complementary, scFe{sub 3}O{sub 4}-NP were introduced into a moving bed biofilm reactor (MBBR) to be observed for 27 d. Mass balances revealed that scFe{sub 3}O{sub 4}-NP sorbed to the biofilm within a few minutes, but that the total biosorption was rather low (3.2 μg Fe/mg TSS). scFe{sub 3}O{sub 4}-NP mainly sorbed to the biofilm surface inducing the detachment of outer biofilm parts starting after an exposure time of 3 h in the MBBR. The biosorption depended on the exposure concentration of scFe{sub 3}O{sub 4}-NP, but less on the contact time. Most scFe{sub 3}O{sub 4}-NP exited the flow cell (up to 65%) and the MBBR (57%) via the effluent. This effect was favored by the stabilization of scFe{sub 3}O{sub 4}-NP in the bulk liquid by organic matter leading to a low retention capacity of the MBBR system. The results contribute to improve our understanding about the fate of ENP in environmental and in

  4. Polychaetes (Annelida: Polychaeta described for the Mexican Pacific: an historical review and an updated checklist Los poliquetos (Annelida: Polychaeta descritos en el Pacífico mexicano: revisión histórica y lista faunística actualizada

    Directory of Open Access Journals (Sweden)

    Pablo Hernández-Alcántara

    2008-01-01

    Full Text Available An updated checklist of the polychaete species described for the Mexican Pacific and an historic review of their study are presented. The taxonomic list includes nomenclature references, data of the type locality and synonyms based on systematic revisions. In the study area, 313 species of polychaetes and 21 genera have been described, of which 278 species are currently valid. Several descriptions (28% of the valid species failed to indicate the habitat of the type locality. The remaining 199 valid species were described for a large variety of habitats: algae (11 species, mangroves (2, hard bottoms (22, soft bottoms (continental shelf = 65 species; deep sea = 78 species, hydrothermal vents (17, and others (parasites, larval planktonic forms, epitokes (4. The species descriptions for the Mexican Pacific can be divided into four main periods: the first, during the 1910s, includes mainly Chamberlin's studies of deep sea fauna. The second, in the 1940s, comprises studies carried out by Rioja (intertidal zone and Hartman (including specimens from the Allan Hancock Foundation collection. The third period began around the 1970s when Fauchald's studies were published and 77 currently valid species were described for western Mexico. The fourth period began in the 1980s and continues to date, being characterized by descriptions of species done mainly by Mexican scientists. The differences in the number of species described during each period and for the different regions of the Mexican Pacific are directly related to the sampling effort carried out along these coasts.Se presenta una lista taxonómica de las especies de poliquetos descritos en el Pacífico mexicano y una revisión histórica de su estudio. El listado incluye referencias nomenclaturales, información sobre la localidad tipo y sinonimias basadas en revisiones sistemáticas. Un total de 313 especies y 21 géneros han sido descritos en el área de estudio, de ellas, 278 especies son

  5. Effects of biofloc promotion on water quality, growth, biomass yield and heterotrophic community in Litopenaeus vannamei (Boone, 1931 experimental intensive cultures

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    Irasema E. Luis-Villaseñor

    2015-08-01

    Full Text Available Six 1.2-m3 tanks were stocked with an initial biomass of 500 g m-3 of Litopenaeus vannamei juveniles (individual weight: 1.0±0.3 g, to evaluate the effect of biofloc promotion on water quality and on shrimp growth and production, and to identify the dominant taxa in the heterotrophic communities present in experimental closed cultures. Feeding was ad libitum twice daily with 35% protein shrimp feed. Three tanks were managed as biofloc technology (BFT systems, adding daily an amount of cornmeal equivalent to 50% of the shrimp feed supplied. The remaining three received only shrimp feed and served as controls. Experiment lasted 21 days. The mean concentrations of P-PO4 3- and inorganic dissolved N species (TAN, N-NO2 -, N-NO3 - were significantly lower (P<0.5 in BFT than in the control. The individual final weight, increase in biomass, food, and protein conversion rates were significantly better in BFT than in the control (P<0.05. The mean N content of the shrimp biomass gained in the BFT cultures was equivalent to 45.7% of the protein-N added as feed, and was significantly higher than the 34.7% recycled into shrimp biomass in the control cultures. Bacterial concentrations were not significantly different. Vibrionaceae dominated in both systems; in both some isolates were potential pathogens, and diversity was higher in the control than in the BFT treatment. The advantages of BFT technology are confirmed by the significantly lower TAN and N-NO2 - concentrations, as well as by the better shrimp performance in terms of growth, biomass yield, and food and protein conversion efficiency.

  6. Physical habitat predictors of Manayunkia speciosa distribution in the Klamath River and implications for management of Ceratomyxa shasta, a parasite with a complex life cycle

    Science.gov (United States)

    Jordan, M. S.; Alexander, J. D.; Grant, G. E.; Bartholomew, J. L.

    2011-12-01

    Management strategies for parasites with complex life cycles may target not the parasite itself, but one of the alternate hosts. One approach is to decrease habitat for the alternate host, and in river systems flow manipulations may be employed. Two-dimensional hydraulic models can be powerful tools for predicting the relationship between flow alterations and changes in physical habit, however they require a rigorous definition of physical habitat for the organism of interest. We present habitat characterization data for the case of the alternate host of a salmonid parasite and introduce how it will be used in conjunction with a 2-dimensional hydraulic model. Ceratomyxa shasta is a myxozoan parasite of salmonids that requires a freshwater polychaete Manayunkia speciosa to complete its life cycle. Manayunkia speciosa is a small (3mm) benthic filter-feeding worm that attaches itself perpendicularly to substrate through construction of a flexible tube. In the Klamath River, CA/OR, C. shasta causes significant juvenile salmon mortality, imposing social and economic losses on commercial, sport and tribal fisheries. An interest in manipulating habitat for the polychaete host to decrease the abundance of C. shasta has therefore developed. Unfortunately, there are limited data on the habitat requirements of M. speciosa or the influence of streamflow regime and hydraulics on population dynamics and infection prevalence. This work aims to address these data needs by identifying physical habitat variables that influence the distribution of M. speciosa and determining the relationship between those variables, M. speciosa population density, and C. shasta infection prevalence. Biological samples were collected from nine sites representing three river features (runs, pools, and eddies) within the Klamath River during the summer and fall of 2010 and 2011. Environmental data including depth, velocity, and substrate, were collected at each polychaete sampling location. We tested

  7. In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea.

    KAUST Repository

    Jessen, Christian

    2014-04-08

    In the Central Red Sea, healthy coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing through predator/grazer exclusion and simulated eutrophication through fertilizer addition on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. At the end of the study period invertebrates had almost exclusively colonized shaded tiles. Algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if the investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.

  8. Metabolic rates, enzyme activities and chemical compositions of some deep-sea pelagic worms, particularly Nectonemertes mirabilis (Nemertea; Hoplonemertinea) and Poeobius meseres (Annelida; Polychaeta)

    Science.gov (United States)

    Thuesen, Erik V.; Childress, James J.

    1993-05-01

    Investigations of metabolic rate, enzyme activity and chemical composition were undertaken on two abundant deep-sea pelagic worms: Nectonemertes mirabilis (Nemertea; Hoplonemertinea) and Poeobius meseres (Annelida; Polychaeta). Six other species of worms ( Pelagonemertes brinkmanni (Nemertea) and the following polychaetes: Pelagobia species A, Tomopteris nisseni, Tomopteris pacifica, Tomopteris species A, and Traviopsis lobifera) were captured in smaller numbers and used for comparison in the physiological and biochemical measurements. Polychaete worms had the highest oxygen consumption rates and, along with N. mirabilis, displayed significant size effects on metabolic rate. Poeobius meseres had the lowest rates of oxygen consumption and displayed no significant relationship of oxygen consumption rate to wet weight. No significant effect of size on the activities of citrate synthase, lactate dehydrogenase or pyruvate kinase was observed in P. meseres or N. mirabilis. Lipid content was higher than protein content for all the worms in this study. Carbohydrate was of little significance in these worms and was usually metabolic rates. It appears that polychaete worms as a group have higher metabolic rates than bathypelagic shrimps, copepods and fishes, and may be the animals with the highest metabolic rates in the bathypelagic regions of the world's oceans.

  9. In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea.

    Science.gov (United States)

    Jessen, Christian; Voolstra, Christian R; Wild, Christian

    2014-01-01

    In the Central Red Sea, healthy coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing through predator/grazer exclusion and simulated eutrophication through fertilizer addition on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. At the end of the study period invertebrates had almost exclusively colonized shaded tiles. Algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if the investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.

  10. Interaction between hydrocarbon seepage, chemosynthetic communities, and bottom water redox at cold seeps of the Makran accretionary prism: insights from habitat-specific pore water sampling and modeling

    Directory of Open Access Journals (Sweden)

    D. Fischer

    2012-06-01

    Full Text Available The interaction between fluid seepage, bottom water redox, and chemosynthetic communities was studied at cold seeps across one of the world's largest oxygen minimum zones (OMZ located at the Makran convergent continental margin. Push cores were obtained from seeps within and below the core-OMZ with a remotely operated vehicle. Extracted sediment pore water was analyzed for sulfide and sulfate concentrations. Depending on oxygen availability in the bottom water, seeps were either colonized by microbial mats or by mats and macrofauna. The latter, including ampharetid polychaetes and vesicomyid clams, occurred in distinct benthic habitats, which were arranged in a concentric fashion around gas orifices. At most sites colonized by microbial mats, hydrogen sulfide was exported into the bottom water. Where macrofauna was widely abundant, hydrogen sulfide was retained within the sediment.

    Numerical modeling of pore water profiles was performed in order to assess rates of fluid advection and bioirrigation. While the magnitude of upward fluid flow decreased from 11 cm yr−1 to <1 cm yr−1 and the sulfate/methane transition (SMT deepened with increasing distance from the central gas orifice, the fluxes of sulfate into the SMT did not significantly differ (6.6–9.3 mol m−2 yr−1. Depth-integrated rates of bioirrigation increased from 120 cm yr−1 in the central habitat, characterized by microbial mats and sparse macrofauna, to 297 cm yr−1 in the habitat of large and few small vesicomyid clams. These results reveal that chemosynthetic macrofauna inhabiting the outer seep habitats below the core-OMZ efficiently bioirrigate and thus transport sulfate down into the upper 10 to 15 cm of the sediment. In this way the animals deal with the lower upward flux of methane in outer habitats by stimulating rates of anaerobic oxidation of methane (AOM with sulfate high enough to provide

  11. Microbial plankton communities in the coastal southeastern Black Sea: biomass, composition and trophic interactions

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    Ulgen Aytan

    2018-04-01

    Full Text Available Summary: We investigated biomass and composition of the pico-, nano- and microplankton communities in a coastal station of the southeastern Black Sea during 2011. We also examined trophic interactions within these communities from size-fractionated dilution experiments in February, June and December. Autotrophic and heterotrophic biomasses showed similar seasonal trends, with a peak in June, but heterotrophs dominated throughout the year. Autotrophic biomass was mainly comprised by nanoflagellates and diatoms in the first half of the year, and by dinoflagellates and Synechococcus spp. in the second half. Heterotrophic biomass was mostly dominated by heterotrophic bacteria, followed by nanoflagellates and microzooplankton. Dilution experiments suggest that nano- and microzooplankton were significant consumers of autotrophs and heterotrophic bacteria. More than 100% of bacterial production was consumed by grazers in all experiments, while 46%, 21% and 30% of daily primary production were consumed in February, June and December, respectively. In February, autotrophs were the main carbon source, but in December, it was heterotrophic bacteria. An intermediate situation was observed in June, with similar carbon flows from autotrophs and heterotrophic bacteria. Size-fraction dilution experiments suggested that heterotrophic nanoflagellates are an important link between the high heterotrophic bacterial biomass and microzooplankton. In summary, these results indicate that nano- and microzooplankton were responsible for comprising a significant fraction of total microbial plankton biomass, standing stocks, growth and grazing processes. This suggests that in 2011, the microbial food web was an important compartment of the planktonic food web in the coastal southeastern Black Sea. Keywords: Phytoplankton, Microzooplankton, Carbon biomass, Microbial food web, Grazing, Black Sea

  12. Linking annual N2O emission in organic soils to mineral nitrogen input as estimated by heterotrophic respiration and soil C/N ratio.

    Science.gov (United States)

    Mu, Zhijian; Huang, Aiying; Ni, Jiupai; Xie, Deti

    2014-01-01

    Organic soils are an important source of N2O, but global estimates of these fluxes remain uncertain because measurements are sparse. We tested the hypothesis that N2O fluxes can be predicted from estimates of mineral nitrogen input, calculated from readily-available measurements of CO2 flux and soil C/N ratio. From studies of organic soils throughout the world, we compiled a data set of annual CO2 and N2O fluxes which were measured concurrently. The input of soil mineral nitrogen in these studies was estimated from applied fertilizer nitrogen and organic nitrogen mineralization. The latter was calculated by dividing the rate of soil heterotrophic respiration by soil C/N ratio. This index of mineral nitrogen input explained up to 69% of the overall variability of N2O fluxes, whereas CO2 flux or soil C/N ratio alone explained only 49% and 36% of the variability, respectively. Including water table level in the model, along with mineral nitrogen input, further improved the model with the explanatory proportion of variability in N2O flux increasing to 75%. Unlike grassland or cropland soils, forest soils were evidently nitrogen-limited, so water table level had no significant effect on N2O flux. Our proposed approach, which uses the product of soil-derived CO2 flux and the inverse of soil C/N ratio as a proxy for nitrogen mineralization, shows promise for estimating regional or global N2O fluxes from organic soils, although some further enhancements may be warranted.

  13. Carbon-to-nitrogen ratio affects the biomass composition and the fatty acid profile of heterotrophically grown Chlorella sp. TISTR 8990 for biodiesel production.

    Science.gov (United States)

    Singhasuwan, Somruethai; Choorit, Wanna; Sirisansaneeyakul, Sarote; Kokkaew, Nakhon; Chisti, Yusuf

    2015-12-20

    Chlorella sp. TISTR 8990 was cultivated heterotrophically in media with various initial carbon-to-nitrogen ratios (C/N ratio) and at different agitation speeds. The production of the biomass, its total fatty acid content and the composition of the fatty acids were affected by the C/N ratio, but not by agitation speed in the range examined. The biomass production was maximized at a C/N mass ratio of 29:1. At this C/N ratio, the biomass productivity was 0.68gL(-1)d(-1), or nearly 1.6-fold the best attainable productivity in photoautotrophic growth. The biomass yield coefficient on glucose was 0.62gg(-1) during exponential growth. The total fatty acids (TFAs) in the freeze-dried biomass were maximum (459mgg(-1)) at a C/N ratio of 95:1. Lower values of the C/N ratio reduced the fatty acid content of the biomass. The maximum productivity of TFAs (186mgL(-1)d(-1)) occurred at C/N ratios of 63:1 and higher. At these conditions, the fatty acids were mostly of the polyunsaturated type. Allowing the alga to remain in the stationary phase for a prolonged period after N-depletion, reduced the level of monounsaturated fatty acids and the level of polyunsaturated fatty acids increased. Biotin supplementation of the culture medium reduced the biomass productivity relative to biotin-free control, but had no effect on the total fatty acid content of the biomass. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Microbiological assessment of house and imported bottled water by comparison of bacterial endotoxin concentration, heterotrophic plate count, and fecal coliform count.

    Science.gov (United States)

    Reyes, Mayra I; Pérez, Cynthia M; Negrón, Edna L

    2008-03-01

    Consumers increasingly use bottled water and home water treatment systems to avoid direct tap water. According to the International Bottled Water Association (IBWA), an industry trade group, 5 billion gallons of bottled water were consumed by North Americans in 2001. The principal aim of this study was to assess the microbial quality of in-house and imported bottled water for human consumption, by measurement and comparison of the concentration of bacterial endotoxin and standard cultivable methods of indicator microorganisms, specifically, heterotrophic and fecal coliform plate counts. A total of 21 brands of commercial bottled water, consisting of 10 imported and 11 in-house brands, selected at random from 96 brands that are consumed in Puerto Rico, were tested at three different time intervals. The Standard Limulus Amebocyte Lysate test, gel clot method, was used to measure the endotoxin concentrations. The minimum endotoxin concentration in 63 water samples was less than 0.0625 EU/mL, while the maximum was 32 EU/mL. The minimum bacterial count showed no growth, while the maximum was 7,500 CFU/mL. Bacterial isolates like P. fluorescens, Corynebacterium sp. J-K, S. paucimobilis, P. versicularis, A. baumannii, P. chlororaphis, F. indologenes, A. faecalis and P. cepacia were identified. Repeated measures analysis of variance demonstrated that endotoxin concentration did not change over time, while there was a statistically significant (p bacterial count over time. In addition, multiple linear regression analysis demonstrated that a unit change in the concentration of endotoxin across time was associated with a significant (p bacterial growth was not detected in some water samples, endotoxin was present. Measurement of Gram-negative bacterial endotoxins is one of the methods that have been suggested as a rapid way of determining bacteriological water quality.

  15. Molecular detection of Kudoa septempunctata (Myxozoa: Multivalvulida in sea water and marine invertebrates

    Directory of Open Access Journals (Sweden)

    Alagesan Paari

    2017-08-01

    Full Text Available Abstract The exportation of cultured olive flounder (Paralichthys olivaceus in Korea has been recently decreasing due to the infections with a myxozoan parasite Kudoa septempunctata, and there is a strong demand for strict food safety management because the food poisoning associated with consumption of raw olive flounder harbouring K. septempunctata has been frequently reported in Japan. The life cycle and infection dynamics of K. septempunctata in aquatic environment are currently unknown, which hamper establishment of effective control methods. We investigated sea water and marine invertebrates collected from olive flounder farms for detecting K. septempunctata by DNA-based analysis, to elucidate infection dynamics of K. septempunctata in aquaculture farms. In addition, live marine polychaetes were collected and maintained in well plates to find any possible actinosporean state of K. septempunctata. The level of K. septempunctata DNA in rearing water fluctuated during the sampling period but the DNA was not detected in summer (June–July in farm A and August in farm B. K. septempunctata DNA was also detected in the polychaetes Naineris laevigata intestinal samples, showing decreased pattern of 40 to 0%. No actinosporean stage of K. septempunctata was observed in the polychaetes by microscopy. The absence of K. septempunctata DNA in rearing water of fish farm and the polychaetes N. laevigata intestinal samples during late spring and early summer indicate that the infection may not occur during this period. N. laevigata was suspected as the possible alternate invertebrate host of K. septempunctata, but the actinosporean stage was not found by well plate method and further studies will be necessary. This research provides important baseline information for understanding the infection dynamics of K. septempunctata in olive flounder farms and further establishment of control strategies.

  16. Are Sediments a Source of Fukushima Radiocesium for Marine Fauna in Coastal Japan?

    Science.gov (United States)

    Wang, C.; Fisher, N. S.; Baumann, Z.

    2016-02-01

    The Fukushima nuclear power plant accident in 2011 resulted in the largest accidental release of artificial radionuclides into the world's oceans. Among the fission products released in large quantities, 137Cs has the greatest potential for long-term impacts on marine biota and human consumers of seafood. In particular, some species of bottom fish near Fukushima were very contaminated and had higher radiocesium (134Cs and 137Cs) levels than pelagic fish in the same area, sometimes exceeding Japanese safety limits >4 years after the accident. Benthic invertebrates, many being prey items for bottom fish, show the same slow decrease in radiocesium as sediments, suggesting that contaminated sediment could be a source of radiocesium for benthic fauna. We evaluated the binding of 137Cs to sediments (Kd found to be 44-60 ml g-1) and found that bioturbation by the polychaete Nereis succinea greatly increased the initial release rate of Cs to overlying seawater. We also assessed the bioavailability of dissolved and sediment-bound Cs for deposit-feeding polychaetes, and its subsequent transfer to crabs and fish, and measured the influence of water temperature on Cs accumulation in fish. Assimilation efficiency (AE) of ingested 137Cs ranged from 16% in polychaetes ingesting sediments to 79% in fish ingesting worms. Efflux rate constants ranged from 5% d-1 for killifish to 40% d-1 for polychaetes. Animal absorption and retention of dissolved 137Cs were also measured. These parameters are used to model radiocesium bioaccumulation and trophic transfer in benthic food chains. Our results are consistent with the idea that sediments can be an important source of Cs for benthic food chains and help explain why some species of bottom fish remained more contaminated than pelagic fish in Japanese coastal waters.

  17. Improvement of lipid content in green algae for subsequent use in bio-fuel production

    International Nuclear Information System (INIS)

    Mojtaba Azma; Raha Abdul Rahim; Rosfarizan Mohamad; Arbakariya Ariff

    2009-01-01

    Full text: Heterotrophic cultivation technique of microalgae, Tetraselmis suecica, in shake flask under different medium composition and culture conditions were developed aimed at improvement of the cell composition and biomass production for subsequent used in bio diesel synthesis. Heterotrophic microalgae cell was developed from the adaptation of the photo trophic cell by photo periodic, manipulation of medium and culture conditions. The performance of heterotrophic cultivation of T. suecica was substantially improved in term of growth rate, final cell concentration, specific growth rate and productivity as well as cell composition especially totals lipid concentration. The cultivation time to reach maximum cell concentration was decreased from 408 hr in photoautotrophic to 142 hr in heterotrophic cultivation. The final cell concentration (24.3 g/L) was increased more than three times in heterotrophic cultivation as compared to that obtained in photoautotrophic cultivation (8.4 g/L). In addition, the maximum productivity (0.17 g/L.h -1 ) for heterotrophic cultivation was nine times higher than photoautotrophic cultivation (0.02 g/L.h -1 ). Moreover the among of protein decreased from 47.7 percentage of dry cell weight in photoautotrophic to 10.5 percent in heterotrophic cells. On the other side the total lipid (53.8) and carbohydrate (14.8) percentage of dry cell weight in heterotrophic cells increased more than two times compare with photoautotrophic cells (24.5 and 7.4 respectively) that is very important from bio fuel production viewpoint. (author)

  18. In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea

    Directory of Open Access Journals (Sweden)

    Christian Jessen

    2014-04-01

    Full Text Available In the Central Red Sea, healthy coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing through predator/grazer exclusion and simulated eutrophication through fertilizer addition on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. At the end of the study period invertebrates had almost exclusively colonized shaded tiles. Algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if the investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.

  19. Uptake and loss of dissolved 109Cd and 75Se in estuarine macroinvertebrates.

    Science.gov (United States)

    Alquezar, Ralph; Markich, Scott J; Twining, John R

    2007-04-01

    Semaphore crabs (Heloecius cordiformis), soldier crabs (Mictyris platycheles), ghost shrimps (Trypaea australiensis), pygmy mussels (Xenostrobus securis), and polychaetes (Eunice sp.), key benthic prey items of predatory fish commonly found in estuaries throughout southeastern Australia, were exposed to dissolved (109)Cd and (75)Se for 385 h at 30 k Bq/l (uptake phase), followed by exposure to radionuclide-free water for 189 h (loss phase). The whole body uptake rates of (75)Se by pygmy mussels, semaphore crabs and soldier crabs were 1.9, 2.4 and 4.1 times higher than (109)Cd, respectively. There were no significant (P>0.05) differences between the uptake rates of (75)Se and (109)Cd for ghost shrimps and polychaetes. The uptake rates of (109)Cd and (75)Se were highest in pygmy mussels; about six times higher than in soldier crabs for (109)Cd and in polychaetes for (75)Se - the organisms with the lowest uptake rates. The loss rates of (109)Cd and (75)Se were highest in semaphore crabs; about four times higher than in polychaetes for (109)Cd and nine times higher than in ghost shrimps for (75)Se - the organisms with the lowest loss rates. The loss of (109)Cd and (75)Se in all organisms was best described by a two (i.e. short and a longer-lived) compartment model. In the short-lived, or rapidly exchanging, compartment, the biological half-lives of (75)Se (16-39 h) were about three times greater than those of (109)Cd (5-12h). In contrast, the biological half-lives of (109)Cd in the longer-lived, or slowly exchanging compartment(s), were typically greater (1370-5950 h) than those of (75)Se (161-1500 h). Semaphore crabs had the shortest biological half-lives of both radionuclides in the long-lived compartment, whereas polychaetes had the greatest biological half-life for (109)Cd (5950 h), and ghost shrimps had the greatest biological half-life for (75)Se (1500 h). This study provides the first reported data for the biological half-lives of Se in estuarine decapod

  20. Plutonium isotope ratios in polychaete worms

    International Nuclear Information System (INIS)

    Beasley, T.M.; Fowler, S.W.

    1976-01-01

    Reference is made to recent reports that suggest that terrestrial and aquatic organisms may preferentially take up 238 Pu compared with sup(239+240)Pu. It is stated that although kinetic isotope effects are known to occur in biological systems for low mass number elements, such as H, C and N, such effects are generally discounted with higher mass numbers, and differences in the biological 'uptake' of isotopes of high mass number elements, such as those of Pu, are normally attributable to differences in the chemical or physical forms of the isotopes or to different quantities of isotopes available to organisms. This has been applied to explain differential Pu isotope behaviour in animals under controlled laboratory conditions, but it is not certain that it can be applied to explain anomalies of Pu isotope behaviour in organisms contaminated by nuclear test debris or by wastes from nuclear fuel reprocessing plants. Geochemical weathering may also have an effect. Described here are experiments in which it was found that deposit feeding marine worms living in sediments contaminated in different ways with Pu isotopes did not show preferential accumulation of 238 Pu. The worms had been exposed to different chemical and physical forms of the isotopes, including exposure to laboratory-labelled sediment, sediment collected from a former weapons test site, and sediment contaminated by wastes from a nuclear fuel reprocessing plant. The worms were allowed to accumulate Pu for times of 5 to 40 days. Isotope ratios were determined by α-spectrometric techniques. It is considered that the results are important for environmental samples where Pu activity levels are low. (U.K.)

  1. [Effects of drip irrigation with plastic mulching on the net primary productivity, soil heterotrophic respiration, and net CO2 exchange flux of cotton field ecosystem in Xinjiang, Northwest China].

    Science.gov (United States)

    Li, Zhi-Guo; Zhang, Run-Hua; Lai, Dong-Mei; Yan, Zheng-Yue; Jiang, Li; Tian, Chang-Yan

    2012-04-01

    In April-October, 2009, a field experiment was conducted to study the effects of drip irrigation with plastic mulching (MD) on the net primary productivity (NPP), soil heterotrophic respiration (Rh) , and net CO2 exchange flux (NEF(CO2)) of cotton field ecosystem in Xinjiang, taking the traditional flood irrigation with no mulching (NF) as the control. With the increasing time, the NPP, Rh, and NEF(CO2) in treatments MD and NF all presented a trend of increasing first and decreased then. As compared with NF, MD increased the aboveground and belowground biomass and the NPP of cotton, and decreased the Rh. Over the whole growth period, the Rh in treatment MD (214 g C x m(-2)) was smaller than that in treatment NF (317 g C x m(-2)), but the NEF(CO2) in treatment MD (1030 g C x m(-2)) was higher than that in treatment NF (649 g C x m(-2)). Treatment MD could fix the atmospheric CO2 approximately 479 g C x m(-2) higher than treatment NF. Drip irrigation with plastic mulching could promote crop productivity while decreasing soil CO2 emission, being an important agricultural measure for the carbon sequestration and emission reduction of cropland ecosystems in arid area.

  2. A deep sea community at the Kebrit brine pool in the Red Sea

    KAUST Repository

    Vestheim, Hege

    2015-02-26

    Approximately 25 deep sea brine pools occur along the mid axis of the Red Sea. These hypersaline, anoxic, and acidic environments have previously been reported to host diverse microbial communities. We visited the Kebrit brine pool in April 2013 and found macrofauna present just above the brine–seawater interface (~1465 m). In particular, inactive sulfur chimneys had associated epifauna of sea anemones, sabellid type polychaetes, and hydroids, and infauna consisting of capitellid polychaetes, gastropods of the genus Laeviphitus (fam. Elachisinidae), and top snails of the family Cocculinidae. The deep Red Sea generally is regarded as extremely poor in benthos. We hypothesize that the periphery along the Kebrit holds increased biomass and biodiversity that are sustained by prokaryotes associated with the brine pool or co-occurring seeps.

  3. Variable phosphorus uptake rates and allocation across microbial groups in the oligotrophic Gulf of Mexico.

    Science.gov (United States)

    Popendorf, Kimberly J; Duhamel, Solange

    2015-10-01

    Microbial uptake of dissolved phosphorus (P) is an important lever in controlling both microbial production and the fate and cycling of marine P. We investigated the relative role of heterotrophic bacteria and phytoplankton in P cycling by measuring the P uptake rates of individual microbial groups (heterotrophic bacteria and the phytoplankton groups Synechococcus, Prochlorococcus and picoeukaryotic phytoplankton) in the P-depleted Gulf of Mexico. Phosphorus uptake rates were measured using incubations with radiolabelled phosphate and adenosine triphosphate coupled with cell sorting flow cytometry. We found that heterotrophic bacteria were the dominant consumers of P on both a biomass basis and a population basis. Biovolume normalized heterotrophic bacteria P uptake rate per cell (amol P μm(-3) h(-1)) was roughly an order of magnitude greater than phytoplankton uptake rates, and heterotrophic bacteria were responsible for generally greater than 50% of total picoplankton P uptake. We hypothesized that this variation in uptake rates reflects variation in cellular P allocation strategies, and found that, indeed, the fraction of cellular P uptake utilized for phospholipid production was significantly higher in heterotrophic bacteria compared with cyanobacterial phytoplankton. These findings indicate that heterotrophic bacteria have a uniquely P-oriented physiology and play a dominant role in cycling dissolved P. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Biotic and abiotic influences on rocky intertidal biomass and ...

    African Journals Online (AJOL)

    composition of these zones, noting the characteristic dominants. Subtidal fringe ... algae and contains an extremely rich associated fauna of small crustaceans, errant polychaetes ..... by most authors (Brown & Jarman 1978), and Stephenson.

  5. Heterotrophic soil respiration in drained peatlands: Abiotic drivers, and changes after clearfelling and afforestation

    Energy Technology Data Exchange (ETDEWEB)

    Maekiranta, P.

    2012-07-01

    Climate change is likely to affect the large carbon (C) stocks of northern peatlands. These C reservoirs may further be affected by human-induced forestry activities and changes in land use. Possible responses of peatland C storages to these changes have significant uncertainties mainly because of the difficulties in predicting peat decomposition rates in changing conditions. This study aims at revealing the effects of abiotic drivers, especially soil temperature and water table level (WL), on peat decomposition rate indicated by heterotrophic peat soil respiration (R{sub PEAT}) in drained forested peatlands. Furthermore it aims to describe the changes in R{sub PEAT} following clearfelling in forestry-drained peatlands and afforestation of former agricultural organic soil croplands. For this, R{sub PEAT} was estimated using chambers to measure CO{sub 2} efflux from trenched litter-free plots, at nine afforested organic soil cropland sites and one forestrydrained site with clearfelling treatment. This study revealed that within the studied sites soil temperature was the main driver of R{sub PEAT}. It was also apparent that the old peat storage in these sites was rather resistant to the short-term changes in WL conditions; i.e. fluctuations of WL caused only minor changes in R{sub PEAT}. The study also demonstrated that in low water level conditions there were mechanisms that could hinder R{sub PEAT}. Excessive WL drawdown (>61cm ) was observed to reduce R{sub PEAT} and furthermore, in low water level conditions the temperature sensitivity of R{sub PEAT} was reduced. These findings suggest that climate change and the associated increase in temperature would have the potential to substantially increase soil C release from drained peatlands. This C release may, however, be constrained, if warming is accompanied by changes in evapotranspiration, precipitation regimes, or the frequency of extreme events (e.g. droughts) that would severely affect WL and surface soil

  6. Strong, weak, and missing links in a microbial community of the N.W. Mediterranean Sea.

    Science.gov (United States)

    Bettarel, Y; Dolan, J R; Hornak, K; Lemée, R; Masin, M; Pedrotti, M-L; Rochelle-Newall, E; Simek, K; Sime-Ngando, T

    2002-12-01

    Planktonic microbial communities often appear stable over periods of days and thus tight links are assumed to exist between different functional groups (i.e. producers and consumers). We examined these links by characterizing short-term temporal correspondences in the concentrations and activities of microbial groups sampled from 1 m depth, at a coastal site of the N.W. Mediterranean Sea, in September 2001 every 3 h for 3 days. We estimated the abundance and activity rates of the autotrophic prokaryote Synechococcus, heterotrophic bacteria, viruses, heterotrophic nanoflagellates, as well as dissolved organic carbon concentrations. We found that Synechococcus, heterotrophic bacteria, and viruses displayed distinct patterns. Synechococcus abundance was greatest at midnight and lowest at 21:00 and showed the common pattern of an early evening maximum in dividing cells. In contrast, viral concentrations were minimal at midnight and maximal at 18:00. Viral infection of heterotrophic bacteria was rare (0.5-2.5%) and appeared to peak at 03:00. Heterotrophic bacteria, as % eubacteria-positive cells, peaked at midday, appearing loosely related to relative changes in dissolved organic carbon concentration. Bacterial production as assessed by leucine incorporation showed no consistent temporal pattern but could be related to shifts in the grazing rates of heterotrophic nanoflagellates and viral infection rates. Estimates of virus-induced mortality of heterotrophic bacteria, based on infection frequencies, were only about 10% of cell production. Overall, the dynamics of viruses appeared more closely related to Synechococcus than to heterotrophic bacteria. Thus, we found weak links between dissolved organic carbon concentration, or grazing, and bacterial activity, a possibly strong link between Synechococcus and viruses, and a missing link between light and viruses.

  7. The Effect of Light on Bacterial Activity in a Seaweed Holobiont.

    Science.gov (United States)

    Coelho-Souza, Sergio A; Jenkins, Stuart R; Casarin, Antonio; Baeta-Neves, Maria Helena; Salgado, Leonardo T; Guimaraes, Jean R D; Coutinho, Ricardo

    2017-11-01

    Holobionts are characterized by the relationship between host and their associated organisms such as the biofilm associated with macroalgae. Considering that light is essential to macroalgae survival, the aim of this study was to verify the effect of light on the heterotrophic activity in biofilms of the brown macroalgae Sargassum furcatum during its growth cycle. Measurements of heterotrophic activity were done under natural light levels at different times during a daily cycle and under an artificial extinction of natural light during the afternoon. We also measured Sargassum primary production under these light levels in the afternoon. Both measurements were done with and without photosynthesis inhibitor and antibiotics. Biofilm composition was mainly represented by bacteria but diatoms, cyanobacteria, and other organisms were also common. When a peak of diatom genera was recorded, the heterotrophic activity of the biofilm was higher. Heterotrophic activity was usually highest during the afternoon and the presence of a photosynthesis inhibitor caused an average reduction of 17% but there was no relationship with Sargassum primary production. These results indicate that autotrophic production in the biofilm was reduced by the inhibitor with consequences on bacterial activity. Heterotrophic activity was mainly bacterial and the antibiotics chloramphenicol and penicillin were more effective than streptomycin. We suggest primary producers in the biofilm are more important to increase bacterial activity than the macroalgae itself because of coherence of the peaks of heterotrophic and autotrophic activity in biofilm during the afternoon and the effects of autotrophic inhibitors on heterotrophic activity.

  8. Influence of Eunice norvegica on feeding and calcification in the coral Lophelia pertusa

    Science.gov (United States)

    Mueller, C. E.; van Oevelen, D.; Middelburg, J. J.; Lundälv, T.

    2012-04-01

    Lophelia pertusa is the main framework building cold-water coral in the North Atlantic. It forms complex reef structures, extending up to several km in length and several meters in hight. Many species are attracted by the coral frame work, forming a highly diverse community within the reef. Although most work has focused on the corals, the functioning of the system also depends on interactions between corals and associated species. A particular example is the Polychaete Eunice norvegica that lives in close association with the coral host. The Polychaete builds a thin texture-tube between living coral branches and stimulates the coral to calcify the tube. This process strengthens the reef framwork by thickening and connecting coral brances and thereby acts as a positive feedback on the development of large reef structures. This comes however at an metabolic cost for the coral due to the enhanced calcificationrates. Another negative feedback for cold-water coral may be food related, since aquaria observations have shown that Eunice occasionally steels food from its host coral. In this study we investigated the interactions between the coral and polychaete related to calcification and food partitioning for two food types (algae and Artemia). The uptake of 13C and 15N labeled food sources by the worm and the coral was studied in chambers with only corals, only the polychaete and both species present. After 7 days, corals and worms were analyzed for isotope incorporation in bulk tissue and skeleton samples and specific fatty acids (13C) using GC-c-IRMS (gas-chromatography-combustion-isotope ratio mass spectrometry). Corals that were kept in the presence of Eunice indeed showed a higher calcification rates of 7.4 ug C (day* g dw coral)-1, evidencing the stimulation of calcification by Eunice. Interestingly, food uptake of algae and Artemia was higher in the coral-worm treatment for both species as compared to the single species treatments. These results shed new light on

  9. Zooplankton biomass and composition in the western Bay of Bengal during late sw monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Madhupratap, M.; Nair, V.R.; Nair, S.R.S.; Rao, T.S.S.

    and neritic regions of the southwestern Bay of Bengal. Other groups like chaetognaths, ostracods, amphipods, euphausiids, fish eggs, fish larvae, polychaetes, cladocerans, planktonic molluscs, etc. contributed to a lesser percentage of the general composition...

  10. Size matters: The contribution of mega-infauna to the food webs and ecosystem services of an Oregon estuary - ESA

    Science.gov (United States)

    Background/Questions/Methods Large-bodied invertebrates (bivalves, polychaetes, burrowing shrimps) are common to infaunal communities of NE Pacific estuaries, but their contribution to estuarine community structure, function and ecosystem services is poorly understood because ...

  11. Benthic fauna of Kakinada bay and backwaters, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rathod, V.; Ansari, Z.A.; Parulekar, A.H.

    . Nematodes, polychaetes, foraminifera and turbellarians were the major groups constituting the bulk of meiofauna, both in the backwaters and near-shore region. Macrofaunal diversity was higher in the near-shore region. Impoverishment of fauna...

  12. Reversible anti-settlement activity against Amphibalanus (= Balanus ) amphitrite, Bugula neritina , and Hydroides elegans by a nontoxic pharmaceutical compound, mizolastine

    KAUST Repository

    Zhou, Xiaojian; Xu, Ying; Jin, Cuili; Qian, Pei-Yuan

    2009-01-01

    Mizolastine, an antihistamine pharmaceutical, was found to significantly inhibit larval settlement of the barnacle Amphibalanus (=Balanus) amphitrite, the bryozoan Bugula neritina, and the polychaete Hydroides elegans with EC50 values of 4.2, 11

  13. Benthic communities associated with ferromanganese nodules from the Central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Pavithran, S.; Goltekar, R.

    for grazers, shelter for burrowers and sessile organisms as well as protection for mobile fauna. It is concluded that benthic organisms like nematodes, polychaetes and foraminiferas may have strong influence on nodule formation and growth....

  14. DIGESTIVE BIOAVAILABILITY TO A DEPOSIT FEDDER (ARENICOLA MARINA) OF POLYCYCLIC AROMATIC HYDROCARBONS ASSOCIATED WITH ANTHRPOGENIC PARTICLES

    Science.gov (United States)

    Marine sediments around urban areas serve as catch basins for anthropogenic particles containing polycyclic aromatic hydrocarbons (PAHs). Using incubations with gut fluids extracted from a deposit-feeding polychaete (Arenicola marina), we determined the digestive bioavailability ...

  15. Soft sediment dwelling macro-invertebrates of Rajapur Bay, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Harkantra, S.N.; Parulekar, A.H.

    Thirtyfour species of soft sediment dwelling macro-invertebrates were recorded in Rajapur Bay at the proposed effluent discharge location of nuclear power plant. The fauna mainly composed of polychaetes (42.52%), molluscs (39.03%), crustaceans (7...

  16. Benthic macro and meiofauna of seagrass (Thalassia hemprichii) bed at Minicoy, Lakshadweep

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari, Z.A.

    Macrofauna, comprising 9 groups, was dominated by polychaete worms, while meiofauna, comprising 10 groups, was dominated by nematodes Densities of both macro and meiofauna were higher near the shore where biomass of Thalassia hemprichii was maximum...

  17. Size matters: The contribution of mega-infauna to the food webs and ecosystem services of an Oregon estuary - 9-30-12

    Science.gov (United States)

    Large-bodied invertebrates (bivalves, polychaetes, burrowing shrimps) are common to infaunal communities of NE Pacific estuaries, but their contribution to estuarine community structure, function and ecosystem services is poorly understood because they are difficult to sample and...

  18. Feeding behaviour and food selection in the horseshoe crab, Tachypleus gigas (Muller)

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A; Mishra, J.K.; Parulekar, A

    The Indian horseshoe crab, Tachypleus gigas, is a benthic feeder which subsists mainly on molluscs, decayed organic matter and polychaetes, in order of prevalence. A strong and positive preference was recorded for molluscs over other food organisms...

  19. Expression of the pair-rule gene homologs runt, Pax3/7, even-skipped-1 and even-skipped-2 during larval and juvenile development of the polychaete annelid Capitella teleta does not support a role in segmentation

    Directory of Open Access Journals (Sweden)

    Seaver Elaine C

    2012-04-01

    Full Text Available Abstract Background Annelids and arthropods each possess a segmented body. Whether this similarity represents an evolutionary convergence or inheritance from a common segmented ancestor is the subject of ongoing investigation. Methods To investigate whether annelids and arthropods share molecular components that control segmentation, we isolated orthologs of the Drosophila melanogaster pair-rule genes, runt, paired (Pax3/7 and eve, from the polychaete annelid Capitella teleta and used whole mount in situ hybridization to characterize their expression patterns. Results When segments first appear, expression of the single C. teleta runt ortholog is only detected in the brain. Later, Ct-runt is expressed in the ventral nerve cord, foregut and hindgut. Analysis of Pax genes in the C. teleta genome reveals the presence of a single Pax3/7 ortholog. Ct-Pax3/7 is initially detected in the mid-body prior to segmentation, but is restricted to two longitudinal bands in the ventral ectoderm. Each of the two C. teleta eve orthologs has a unique and complex expression pattern, although there is partial overlap in several tissues. Prior to and during segment formation, Ct-eve1 and Ct-eve2 are both expressed in the bilaterial pair of mesoteloblasts, while Ct-eve1 is expressed in the descendant mesodermal band cells. At later stages, Ct-eve2 is expressed in the central and peripheral nervous system, and in mesoderm along the dorsal midline. In late stage larvae and adults, Ct-eve1 and Ct-eve2 are expressed in the posterior growth zone. Conclusions C. teleta eve, Pax3/7 and runt homologs all have distinct expression patterns and share expression domains with homologs from other bilaterians. None of the pair-rule orthologs examined in C. teleta exhibit segmental or pair-rule stripes of expression in the ectoderm or mesoderm, consistent with an independent origin of segmentation between annelids and arthropods.

  20. Seasonal variations of the composition of microbial biofilms in sandy tidal flats: Focus of fatty acids, pigments and exopolymers

    Science.gov (United States)

    Passarelli, Claire; Meziane, Tarik; Thiney, Najet; Boeuf, Dominique; Jesus, Bruno; Ruivo, Mickael; Jeanthon, Christian; Hubas, Cédric

    2015-02-01

    Biofilms, or microbial mats, are common associations of microorganisms in tidal flats; they generally consist of a large diversity of organisms embedded in a matrix of Extracellular Polymeric Substances (EPS). These molecules are mainly composed of carbohydrates and proteins, but their detailed monomer compositions and seasonal variations are currently unknown. Yet this composition determines the numerous roles of biofilms in these systems. This study investigated the changes in composition of carbohydrates in intertidal microbial mats over a year to decipher seasonal variations in biofilms and in varying hydrodynamic conditions. This work also aimed to assess how these compositions are related to microbial assemblages. In this context, natural biofilms whose development was influenced or not by artificial structures mimicking polychaete tubes were sampled monthly for over a year in intertidal flats of the Chausey archipelago. Biofilms were compared through the analysis of their fatty acid and pigment contents, and the monosaccharide composition of their EPS carbohydrates. Carbohydrates from both colloidal and bound EPS contained mainly glucose and, to a lower extent, galactose and mannose but they showed significant differences in their detailed monosaccharide compositions. These two fractions displayed different seasonal evolution, even if glucose accumulated in both fractions in summer; bound EPS only were affected by artificial biogenic structures. Sediment composition in fatty acids and pigments showed that microbial communities were dominated by diatoms and heterotrophic bacteria. Their relative proportions, as well as those of other groups like cryptophytes, changed between times and treatments. The changes in EPS composition were not fully explained by modifications of microbial assemblages but also depended on the processes taking place in sediments and on environmental conditions. These variations of EPS compositions are likely to alter different

  1. Influence of environmental properties on macrobenthos in the northwest Indian shelf.

    Science.gov (United States)

    Jayaraj, K A; Jayalakshmi, K V; Saraladevi, K

    2007-04-01

    The paper deals with the standing stock of macrobenthic infauna and associated environmental factors influencing the benthic community in the shelf region of the northwest Indian coast. The data were collected onboard FORV Sagar Sampada during the winter monsoon (January-February, 2003) to understand the community structure and the factors influencing the benthic distribution. The environmental parameters, sediment characteristics and macrobenthic infauna were collected at 26 stations distributed in the depths between 30 and 200 m extending from Mormugao to Porbander. Total benthic abundance was high in lower depths (50-75 m), and low values noticed at 30 m depth contour was peculiar. Polychaetes were the dominant group and were more abundant in shallow and middle depths with moderate organic matter, clay and relatively high dissolved oxygen. On the other hand crustaceans and molluscs were more abundant in deeper areas having sandy sediment and low temperature. High richness and diversity of whole benthic groups observed in deeper depths counter balanced the opposite trend shown by polychaete species. Generally benthos preferred medium grain sized texture with low organic matter and high organic matter had an adverse effect especially on filter feeders. Deposit feeding polychaetes dominated in shallow depths while carnivore species in the middle depths. Ecologically, benthos were controlled by a combination of factors such as temperature, salinity, dissolved oxygen, sand and organic matter and no single factor could be considered as an ecological master factor.

  2. Meiofauna of some sandy beaches of Andaman Islands

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari, Z.A.; Ingole, B.S.

    Comparatively high meiofauna numbers were recorded from beaches having fine sand particles than those having coarse to medium sand particles The fauna was dominated mainly by nematodes (53.7%), harpacticoids (13.7%) and polychaetes (12.8%) On all...

  3. Size Matters: The Contribution of Mega-Infauna to the Food Webs and Ecosystem Services of an Oregon Estuary

    Science.gov (United States)

    Large-bodied, invertebrates are common to infaunal communities of NE Pacific estuaries (e.g., bivalves, polychaetes, burrowing shrimps), but their contribution to the ecological structure, function and ecosystem services of most estuaries has been poorly characterized because the...

  4. Pattern of species succession of soft-bottom macrofauna in the estuaries of Goa, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Harkantra, S.N.; Rodrigues, N.R.

    . Each site exhibited a different pattern of species succession and compostion. A total of 58 species were recorded among which 18 were new to the local fauna. Dominant species that controlled the orientation of this succession were Polychaetes...

  5. Short-term impact of blue mussel dredging ( Mytilus edulis L.) on a benthic community

    DEFF Research Database (Denmark)

    Dolmer, Per; Kristensen, T.; Christiansen, M.L.

    2001-01-01

    The short-term effect of mussel dredging in a brackish Danish sound was studied. A commercial dredging track was identified and an analysis of the species composition inside the track and at an adjacent control area showed that dredging changed the community structure by reducing the density...... of polychaetes. In order to investigate the extent and the duration of the dredging impact experimental dredging was conducted. The experimental dredging removed 50% of the mussels in two dredged areas. Immediately after dredging, a significantly lower number of species was measured inside the mussel beds...... in dredged areas compared to control and boundary areas. This effect lasted for at least 40 days. The analysis of the species composition showed that the dredged area had a significantly lower density, particularly of polychaetes compared to the boundary area. An increased number of species was recorded...

  6. Studies on the intertidal macrofauna of the sandy beach at Kavarati atoll (Lakshadweep)

    Digital Repository Service at National Institute of Oceanography (India)

    Narayanan, B.; Sivadas, P.

    The distribution of macrofauna in Kavaratti Atoll is studied in the intertidal region for over a period of 13 months. Several diversity in the faunal composition was not observed. The polychaete Scoloplos sp. and the bivalve Mesodesma glabratum were...

  7. Alkalinity production in intertidal sands intensified by lugworm bioirrigation

    NARCIS (Netherlands)

    Rao, A.M.F.; Malkin, S.Y.; Montserrat, F; Meysman, F.J.R.

    2014-01-01

    Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete

  8. Meiobenthos of Saphala salt marsh, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Ansari, Z.A.; Parulekar, A.H.

    Benthic fauna of the salt marsh comprised 10 taxonomic groups, dominated by nematodes (63.9%), harpacticoids (18.5%), turbellaria (5.6%), crustacean nauplii (5.4%) and polychaetes (4.1%). The population density varied from 282 to 17300 (10 cm)-2...

  9. Biological geography of the European seas: results from the MacroBen database

    NARCIS (Netherlands)

    Arvanitidis, C.; Somerfield, P.J.; Rumohr, H.; Faulwetter, S.; Valavanis, V.; Vasileiadou, A.; Chatzigeorgiou, G.; Vanden Berghe, E.; Vanaverbeke, J.; Labrune, C.; Grémare, A.; Zettler, M.L.; Kedra, M.; Wlodarska-Kowalczuk, M.; Aleffi, I.F.; Amouroux, J.M.; Anisimova, N.; Bachelet, G.; Büntzow, M.; Cochrane, S.J.; Costello, M.J.; Craeymeersch, J.A.; Dahle, S.; Degraer, S.; Denisenko, S.; Dounas, C.; Duineveld, G.; Emblow, C.; Escavarage, V.; Fabri, M.C.; Fleischer, D.; Gray, J.S.; Heip, C.H.R.; Herrmann, M.; Hummel, H.; Janas, U.; Karakassis, I.; Kendall, M.A.; Kingston, P.; Kotwicki, L.; Laudien, J.; Mackie, A.S.Y.; Nevrova, E.L.; Occhipinti-Ambrogi, A.; Oliver, P.G.; Olsgard, F.; Palerud, R.; Petrov, A.; Rachor, E.; Revkov, N.K.; Rose, A.; Sardá, R.; Sistermans, W.C.H.; Speybroeck, J.; Van Hoey, G.; Vincx, M.; Whomersley, P.; Willems, W.; Zenetos, A.

    2009-01-01

    This study examines whether or not biogeographical and/or managerial divisions across the European seas can be validated using soft-bottom macrobenthic community data. The faunal groups used were: all macrobenthos groups, polychaetes, molluscs, crustaceans, echinoderms, sipunculans and the last 5

  10. The benthos of South Lake, St Lucia following a period of stable ...

    African Journals Online (AJOL)

    Haminea petersi; the gastropod Assiminea sp.; the polychaetes. Marphysa macintoshi, Glycera tridactyla and Dendronereis ar-. boriJera; oligochaetes; nemerteans; the crab Hymenosoma or- bicu/are; the tanaid Apseudes digitalis-, the amphipod Grandi- dierella lignorum; cumaceans and the mysid Mesopodopsis africana.

  11. Segmental mode of neural patterning in sipuncula

    DEFF Research Database (Denmark)

    Kristof, Alen; Wollesen, Tim; Wanninger, Andreas

    2008-01-01

    Recent molecular phylogenetic analyses suggest a close relationship between two worm-shaped phyla, the nonsegmented Sipuncula (peanut worms) and the segmented Annelida (e.g., earthworms and polychaetes) [1-5]. The striking differences in their bodyplans are exemplified by the annelids' paired...

  12. Bar-tailed

    NARCIS (Netherlands)

    Duijns, S.; Hidayati, N.A.; Piersma, T.

    2013-01-01

    Capsule Across the European wintering range Bar-tailed Godwits Limosa lapponica lapponica selected polychaete worms and especially Ragworms Hediste diversicolor, with differences between areas due to vari