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Sample records for plankton communities carbohydrates

  1. The structure and evolution of plankton communities

    Science.gov (United States)

    Longhurst, Alan R.

    New understanding of the circulation of ancient oceans is not yet matched by progress in our understanding of their pelagic ecology, though it was the planktonic ecosystems that generated our offshore oil and gas reserves. Can we assume that present-day models of ecosystem function are also valid for ancient seas? This question is addressed by a study of over 4000 plankton samples to derive a comprehensive, global description of zooplankton community structure in modern oceans: this shows that copepods form only 50% of the biomass of all plankton, ranging from 70% in polar to 35% in tropical seas. Comparable figures are derived from 14 other taxonomic categories of zooplankton. For trophic groupings, the data indicate globally: geletinous predators - 14%; gelatinous herbivores - 4%; raptorial predators - 33%; macrofiltering herbivores - 20%; macrofiltering omnivores - 25%; and detritivores - 3%. A simple, idealized model for the modern pelagic ecosystem is derived from these percentages which indicates that metazooplankton are not the most important consumers of pico- and nano-plankton production which itself probably constitutes 90% of primary production in warm oceans. This model is then compared with candidate life-forms available in Palaeozoic and Mesozoic oceans to determine to what extent it is also valid for ancient ecosystems: it is concluded that it is probably unnecessary to postulate models fundamentally differing from it in order to accommodate the life-forms, both protozoic and metazoic, known to have populated ancient seas. Remarkably few life-forms have existed which cannot be paralleled in the modern ocean, which contains remarkably few life-forms which cannot be paralleled in the Palaeozoic ocean. As a first assumption, then, it is reasonable to assume that energy pathways were similar in ancient oceans to those we study today.

  2. Effect of Low ph on Carbohydrate Production by a Marine Planktonic Diatom (Chaetoceros muelleri)

    International Nuclear Information System (INIS)

    Thornton, D.C.O.

    2009-01-01

    Rising carbon dioxide (CO 2 ) concentrations in the atmosphere due to human activity are causing the surface ocean to become more acidic. Diatoms play a pivotal role in biogeochemical cycling and ecosystem function in the ocean. ph affected the quantum efficiency of photosystem II and carbohydrate metabolism in a planktonic diatom (Chaetoceros muelleri), representative of a widely distributed genus. In batch cultures grown at low ph, the proportion of total carbohydrate stored within the cells decreased and more dissolved carbohydrates were exuded from the cells into the surrounding medium. Changes in productivity and the way in which diatoms allocate carbon into carbohydrates may affect ecosystem function and the efficiency of the biological carbon pump in a low ph ocean.

  3. Metabarcoding and metabolome analyses of copepod grazing reveal feeding preference and linkage to metabolite classes in dynamic microbial plankton communities.

    Science.gov (United States)

    Ray, Jessica L; Althammer, Julia; Skaar, Katrine S; Simonelli, Paolo; Larsen, Aud; Stoecker, Diane; Sazhin, Andrey; Ijaz, Umer Z; Quince, Christopher; Nejstgaard, Jens C; Frischer, Marc; Pohnert, Georg; Troedsson, Christofer

    2016-11-01

    In order to characterize copepod feeding in relation to microbial plankton community dynamics, we combined metabarcoding and metabolome analyses during a 22-day seawater mesocosm experiment. Nutrient amendment of mesocosms promoted the development of haptophyte (Phaeocystis pouchetii)- and diatom (Skeletonema marinoi)-dominated plankton communities in mesocosms, in which Calanus sp. copepods were incubated for 24 h in flow-through chambers to allow access to prey particles (<500 μm). Copepods and mesocosm water sampled six times spanning the experiment were analysed using metabarcoding, while intracellular metabolite profiles of mesocosm plankton communities were generated for all experimental days. Taxon-specific metabarcoding ratios (ratio of consumed prey to available prey in the surrounding seawater) revealed diverse and dynamic copepod feeding selection, with positive selection on large diatoms, heterotrophic nanoflagellates and fungi, while smaller phytoplankton, including P. pouchetii, were passively consumed or even negatively selected according to our indicator. Our analysis of the relationship between Calanus grazing ratios and intracellular metabolite profiles indicates the importance of carbohydrates and lipids in plankton succession and copepod-prey interactions. This molecular characterization of Calanus sp. grazing therefore provides new evidence for selective feeding in mixed plankton assemblages and corroborates previous findings that copepod grazing may be coupled to the developmental and metabolic stage of the entire prey community rather than to individual prey abundances. © 2016 John Wiley & Sons Ltd.

  4. Planktonic Subsidies to Surf-Zone and Intertidal Communities

    Science.gov (United States)

    Morgan, Steven G.; Shanks, Alan L.; MacMahan, Jamie H.; Reniers, Ad J. H. M.; Feddersen, Falk

    2018-01-01

    Plankton are transported onshore, providing subsidies of food and new recruits to surf-zone and intertidal communities. The transport of plankton to the surf zone is influenced by wind, wave, and tidal forcing, and whether they enter the surf zone depends on alongshore variation in surf-zone hydrodynamics caused by the interaction of breaking waves with coastal morphology. Areas with gently sloping shores and wide surf zones typically have orders-of-magnitude-higher concentrations of plankton in the surf zone and dense larval settlement in intertidal communities because of the presence of bathymetric rip currents, which are absent in areas with steep shores and narrow surf zones. These striking differences in subsidies have profound consequences; areas with greater subsidies support more productive surf-zone communities and possibly more productive rocky intertidal communities. Recognition of the importance of spatial subsidies for rocky community dynamics has recently advanced ecological theory, and incorporating surf-zone hydrodynamics would be an especially fruitful line of investigation.

  5. Bioavailability of autochthonous dissolved organic nitrogen in marine plankton communities

    DEFF Research Database (Denmark)

    Knudsen, Helle; Markager, Svend Stiig; Søndergaard, Morten

    The purpose of this study was to investigate the bioavailability of dissolved organic nitrogen (DON) produced during a phytoplankton bloom. The experiments were conducted with natural plankton communities as batch growth experiments over approximately 30 days with nitrogen limitation. Five to six...... times during the exponential and stationary phases of each experimental bloom the bioavailability of DON was measured over 60 days together with DOC and oxygen consumption. The overall aim was to quantify remineralization of the added nitrate. The results showed that maximum 33 % of the added nitrate...

  6. Predicting plankton net community production in the Atlantic Ocean

    Science.gov (United States)

    Serret, Pablo; Robinson, Carol; Fernández, Emilio; Teira, Eva; Tilstone, Gavin; Pérez, Valesca

    2009-07-01

    We present, test and implement two contrasting models to predict euphotic zone net community production (NCP), which are based on 14C primary production (PO 14CP) to NCP relationships over two latitudinal (ca. 30°S-45°N) transects traversing highly productive and oligotrophic provinces of the Atlantic Ocean (NADR, CNRY, BENG, NAST-E, ETRA and SATL, Longhurst et al., 1995 [An estimation of global primary production in the ocean from satellite radiometer data. Journal of Plankton Research 17, 1245-1271]). The two models include similar ranges of PO 14CP and community structure, but differ in the relative influence of allochthonous organic matter in the oligotrophic provinces. Both models were used to predict NCP from PO 14CP measurements obtained during 11 local and three seasonal studies in the Atlantic, Pacific and Indian Oceans, and from satellite-derived estimates of PO 14CP. Comparison of these NCP predictions with concurrent in situ measurements and geochemical estimates of NCP showed that geographic and annual patterns of NCP can only be predicted when the relative trophic importance of local vs. distant processes is similar in both modeled and predicted ecosystems. The system-dependent ability of our models to predict NCP seasonality suggests that trophic-level dynamics are stronger than differences in hydrodynamic regime, taxonomic composition and phytoplankton growth. The regional differences in the predictive power of both models confirm the existence of biogeographic differences in the scale of trophic dynamics, which impede the use of a single generalized equation to estimate global marine plankton NCP. This paper shows the potential of a systematic empirical approach to predict plankton NCP from local and satellite-derived P estimates.

  7. UV sensitivity of planktonic net community production in ocean surface waters

    OpenAIRE

    Regaudie de Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

    2014-01-01

    The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we tes...

  8. Temporal changes in plankton of the North Sea: community shfits and environmental drivers

    NARCIS (Netherlands)

    Alvarez-Fernandez, S.; Lindeboom, H.J.; Meesters, H.W.G.

    2012-01-01

    This paper analyses long-term and seasonal changes in the North Sea plankton community during the period 1970 to 2008. Based on Continuous Plankton Recorder (CPR) data covering 38 yr, major changes in both phytoplankton and zooplankton abundance and community structure were identified. Regime

  9. Carbohydrate secretion by phototrophic communities in tidal sediments

    NARCIS (Netherlands)

    de Winder, B.; Staats, N.; Stal, L.J.; Paterson, D.M.

    1999-01-01

    Two different benthic phototrophic communities on tidal flats were investigated for their carbohydrate content and distribution. Carbohydrates were analysed as two operationally defined fractions, related to the difficulty of extraction from the sediment matrix. Water-soluble (colloidal) and EDTA-

  10. Using flow cytometry for counting natural planktonic bacteria and understanding the structure of planktonic bacterial communities

    Directory of Open Access Journals (Sweden)

    Josep M. Gasol

    2000-06-01

    Full Text Available Flow cytometry is rapidly becoming a routine methodology in aquatic microbial ecology. The combination of simple to use bench-top flow cytometers and highly fluorescent nucleic acid stains allows fast and easy determination of microbe abundance in the plankton of lakes and oceans. The different dyes and protocols used to stain and count planktonic bacteria as well as the equipment in use are reviewed, with special attention to some of the problems encountered in daily routine practice such as fixation, staining and absolute counting. One of the main advantages of flow cytometry over epifluorescence microscopy is the ability to obtain cell-specific measurements in large numbers of cells with limited effort. We discuss how this characteristic has been used for differentiating photosynthetic from non-photosynthetic prokaryotes, for measuring bacterial cell size and nucleic acid content, and for estimating the relative activity and physiological state of each cell. We also describe how some of the flow cytometrically obtained data can be used to characterize the role of microbes on carbon cycling in the aquatic environment and we prospect the likely avenues of progress in the study of planktonic prokaryotes through the use of flow cytometry.

  11. UV sensitivity of planktonic net community production in ocean surface waters

    Science.gov (United States)

    Regaudie-de-Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

    2014-05-01

    The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we test the sensitivity of net community production (NCP) to UVB of planktonic communities in surface waters across contrasting regions of the ocean. We observed here that UVB radiation affects net plankton community production at the ocean surface, imposing a shift in NCP by, on average, 50% relative to the values measured when excluding partly UVB. Our results show that under full solar radiation, the metabolic balance shows the prevalence of net heterotrophic community production. The demonstration of an important effect of UVB radiation on NCP in surface waters presented here is of particular relevance in relation to the increased UVB radiation derived from the erosion of the stratospheric ozone layer. Our results encourage design future research to further our understanding of UVB effects on the metabolic balance of plankton communities.

  12. Seasonal variation of plankton communities influenced by environmental factors in an artificial lake

    Science.gov (United States)

    Li, Xuemei; Yu, Yuhe; Zhang, Tanglin; Feng, Weisong; Ao, Hongyi; Yan, Qingyun

    2012-05-01

    We evaluated the seasonal variation in plankton community composition in an artificial lake. We conducted microscopic analysis and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified partial 16S rRNA and 18S rRNA genes to characterize the plankton community. The clustering of unweighted pair group method with arithmetic mean (UPGMA) was then used to investigate the similarity of these plankton communities. DGGE fingerprinting revealed that samples collected at the different sites within a season shared high similarity and were generally grouped together. In contrast, we did not observe any seasonal variation based on microscopic analysis. Redundancy analysis (RDA) of the plankton operational taxonomic units (OTUs) in relation to environmental factors revealed that transparency was negatively correlated with the first axis ( R=-0.931), and temperature and total phosphorus (TP) were positively correlated with the first axis ( R=0.736 and R=0.660, respectively). In conclusion, plankton communities in the artificial lake exhibited significant seasonal variation. Transparency, phosphorus and temperature appear to be the major factors driving the differences in plankton composition.

  13. Spatial Distribution of Viruses Associated with Planktonic and Attached Microbial Communities in Hydrothermal Environments

    Science.gov (United States)

    Nunoura, Takuro; Kazama, Hiromi; Noguchi, Takuroh; Inoue, Kazuhiro; Akashi, Hironori; Yamanaka, Toshiro; Toki, Tomohiro; Yamamoto, Masahiro; Furushima, Yasuo; Ueno, Yuichiro; Yamamoto, Hiroyuki; Takai, Ken

    2012-01-01

    Viruses play important roles in marine surface ecosystems, but little is known about viral ecology and virus-mediated processes in deep-sea hydrothermal microbial communities. In this study, we examined virus-like particle (VLP) abundances in planktonic and attached microbial communities, which occur in physical and chemical gradients in both deep and shallow submarine hydrothermal environments (mixing waters between hydrothermal fluids and ambient seawater and dense microbial communities attached to chimney surface areas or macrofaunal bodies and colonies). We found that viruses were widely distributed in a variety of hydrothermal microbial habitats, with the exception of the interior parts of hydrothermal chimney structures. The VLP abundance and VLP-to-prokaryote ratio (VPR) in the planktonic habitats increased as the ratio of hydrothermal fluid to mixing water increased. On the other hand, the VLP abundance in attached microbial communities was significantly and positively correlated with the whole prokaryotic abundance; however, the VPRs were always much lower than those for the surrounding hydrothermal waters. This is the first report to show VLP abundance in the attached microbial communities of submarine hydrothermal environments, which presented VPR values significantly lower than those in planktonic microbial communities reported before. These results suggested that viral lifestyles (e.g., lysogenic prevalence) and virus interactions with prokaryotes are significantly different among the planktonic and attached microbial communities that are developing in the submarine hydrothermal environments. PMID:22210205

  14. Norwegian deep-water coral reefs: cultivation and molecular analysis of planktonic microbial communities.

    Science.gov (United States)

    Jensen, Sigmund; Lynch, Michael D J; Ray, Jessica L; Neufeld, Josh D; Hovland, Martin

    2015-10-01

    Deep-sea coral reefs do not receive sunlight and depend on plankton. Little is known about the plankton composition at such reefs, even though they constitute habitats for many invertebrates and fish. We investigated plankton communities from three reefs at 260-350 m depth at hydrocarbon fields off the mid-Norwegian coast using a combination of cultivation and small subunit (SSU) rRNA gene and transcript sequencing. Eight months incubations of a reef water sample with minimal medium, supplemented with carbon dioxide and gaseous alkanes at in situ-like conditions, enabled isolation of mostly Alphaproteobacteria (Sulfitobacter, Loktanella), Gammaproteobacteria (Colwellia) and Flavobacteria (Polaribacter). The relative abundance of isolates in the original sample ranged from ∼ 0.01% to 0.80%. Comparisons of bacterial SSU sequences from filtered plankton of reef and non-reef control samples indicated high abundance and metabolic activity of primarily Alphaproteobacteria (SAR11 Ia), Gammaproteobacteria (ARCTIC96BD-19), but also of Deltaproteobacteria (Nitrospina, SAR324). Eukaryote SSU sequences indicated metabolically active microalgae and animals, including codfish, at the reef sites. The plankton community composition varied between reefs and differed between DNA and RNA assessments. Over 5000 operational taxonomic units were detected, some indicators of reef sites (e.g. Flavobacteria, Cercozoa, Demospongiae) and some more active at reef sites (e.g. Gammaproteobacteria, Ciliophora, Copepoda). © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Heterogeneity in physical, chemical and plankton-community structures in Lake Tanganyika

    NARCIS (Netherlands)

    Langenberg, V.T.; Tumba, J.M.; Tshibangu, K.; Lukwesa, C.; Chitamwebwa, D.; Bwebwa, D.; Makasa, L.; Roijackers, R.M.M.

    2008-01-01

    From 28 August to 6 September 1995, we monitored the lake-wide physical, chemical and biological properties of the pelagic waters in Lake Tanganyika. The aim of this study was to examine the spatial environmental variability and its relation to fluctuations in plankton abundance and community

  16. Effects of toxic cyanobacteria on plankton assemblage : community development during decay of Nodularia spumigena

    DEFF Research Database (Denmark)

    Engström-Öst, J.; Koski, Marja; Schmidt, K.

    2002-01-01

    We studied the development of the plankton community in an artificially created toxic Nodularia spumigena bloom during a 2 wk enclosure study at the SW coast of Finland in the Baltic Sea. We measured bacterial abundance, dominant phytoplankton groups and ciliates, as well as concentrations of phy...

  17. Development of north sea coastal plankton communities in separate plastic bags under identical conditions

    NARCIS (Netherlands)

    Kuiper, J.

    1977-01-01

    In two experiments lasting 4 to 6 weeks, communities of North Sea coastal plankton kept in separate plastic bags (of about 1400 l) and exposed to the same environmental conditions showed very similar patterns of growth and decline. This result means that the method is suitable for the evaluation of

  18. Plankton community composition and vertical migration during polar night in Kongsfjorden

    DEFF Research Database (Denmark)

    Grenvald, Julie Cornelius; Callesen, Trine Abraham; Daase, Malin

    2016-01-01

    characterize the plankton community composition during the polar night using water samplers and zooplankton net samples (50, 64, 200, 1500 lm), supplemented by acoustics (ADCPs, 300 kHz), to address a previously unresolved question–which species of zooplankton perform diel vertical migration during the polar...

  19. Microbial eukaryote plankton communities of high-mountain lakes from three continents exhibit strong biogeographic patterns.

    Science.gov (United States)

    Filker, Sabine; Sommaruga, Ruben; Vila, Irma; Stoeck, Thorsten

    2016-05-01

    Microbial eukaryotes hold a key role in aquatic ecosystem functioning. Yet, their diversity in freshwater lakes, particularly in high-mountain lakes, is relatively unknown compared with the marine environment. Low nutrient availability, low water temperature and high ultraviolet radiation make most high-mountain lakes extremely challenging habitats for life and require specific molecular and physiological adaptations. We therefore expected that these ecosystems support a plankton diversity that differs notably from other freshwater lakes. In addition, we hypothesized that the communities under study exhibit geographic structuring. Our rationale was that geographic dispersal of small-sized eukaryotes in high-mountain lakes over continental distances seems difficult. We analysed hypervariable V4 fragments of the SSU rRNA gene to compare the genetic microbial eukaryote diversity in high-mountain lakes located in the European Alps, the Chilean Altiplano and the Ethiopian Bale Mountains. Microbial eukaryotes were not globally distributed corroborating patterns found for bacteria, multicellular animals and plants. Instead, the plankton community composition emerged as a highly specific fingerprint of a geographic region even on higher taxonomic levels. The intraregional heterogeneity of the investigated lakes was mirrored in shifts in microbial eukaryote community structure, which, however, was much less pronounced compared with interregional beta-diversity. Statistical analyses revealed that on a regional scale, environmental factors are strong predictors for plankton community structures in high-mountain lakes. While on long-distance scales (>10 000 km), isolation by distance is the most plausible scenario, on intermediate scales (up to 6000 km), both contemporary environmental factors and historical contingencies interact to shift plankton community structures. © 2016 John Wiley & Sons Ltd.

  20. Differences in planktonic microbial communities associated with three types of macrophyte stands in a shallow lake.

    Science.gov (United States)

    Mentes, Anikó; Szabó, Attila; Somogyi, Boglárka; Vajna, Balázs; Tugyi, Nóra; Csitári, Bianka; Vörös, Lajos; Felföldi, Tamás

    2018-02-01

    Little is known about how various substances from living and decomposing aquatic macrophytes affect the horizontal patterns of planktonic bacterial communities. Study sites were located within Lake Kolon, which is a freshwater marsh and can be characterised by open-water sites and small ponds with different macrovegetation (Phragmites australis, Nymphea alba and Utricularia vulgaris). Our aim was to reveal the impact of these macrophytes on the composition of the planktonic microbial communities using comparative analysis of environmental parameters, microscopy and pyrosequencing data. Bacterial 16S rRNA gene sequences were dominated by members of phyla Proteobacteria (36%-72%), Bacteroidetes (12%-33%) and Actinobacteria (5%-26%), but in the anoxic sample the ratio of Chlorobi (54%) was also remarkable. In the phytoplankton community, Cryptomonas sp., Dinobryon divergens, Euglena acus and chrysoflagellates had the highest proportion. Despite the similarities in most of the measured environmental parameters, the inner ponds had different bacterial and algal communities, suggesting that the presence and quality of macrophytes directly and indirectly controlled the composition of microbial plankton. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Carbohydrates

    Science.gov (United States)

    Carbohydrates are one of the main types of nutrients. They are the most important source of energy for your body. Your digestive system changes carbohydrates into glucose (blood sugar). Your body uses this ...

  2. Plankton community dynamics in a subtropical lagoonal system and related factors

    Directory of Open Access Journals (Sweden)

    LETÍCIA DONADEL

    2016-03-01

    Full Text Available ABSTRACT Changes of the plankton community in a shallow, subtropical lagoonal system and its relation to environmental conditions were investigated during an annual cycle to provide information on its spatial and seasonal variation pattern. The study carried out at four sites (three in the Peixe lagoon and one in the Ruivo lagoon, which are located in the Lagoa do Peixe National Park, southern Brazil. The system has a temporary connection to the Atlantic Ocean by a narrow channel. The phytoplankton density was higher in the Peixe lagoon whereas the specific richness was higher in the Ruivo lagoon which is also a site with the lower salinity. The phytoplankton biomass near the channel showed seasonal variation with the highest value in fall and lowest in winter. Zooplankton richness was inversely correlated with salinity, and had the highest values in the Ruivo lagoon. Ordination analysis indicated seasonal and spatial patterns in plankton community in this lagoonal system, related to variation in salinity. In addition, the wind action and precipitation were important factors on the spatial and seasonal salinity changes in the lagoon with direct influence on the plankton community dynamics.

  3. Cultivation of seaweed Gracilaria lemaneiformis enhanced biodiversity in a eukaryotic plankton community as revealed via metagenomic analyses.

    Science.gov (United States)

    Chai, Zhao Yang; He, Zhi Li; Deng, Yun Yan; Yang, Yu Feng; Tang, Ying Zhong

    2018-02-01

    Plankton diversity reflects the quality and health of waters and should be monitored as a critical feature of marine ecosystems. This study applied a pair of 28S rRNA gene-specific primers and pyrosequencing to assess the effects of large-scale cultivation of the seaweed Gracilaria lemaneiformis on the biodiversity of eukaryotic plankton community in the coastal water of Guangdong, China. With 1 million sequences (2,221 operational taxonomic units [OTUs]) obtained from 51 samples, we found that the biodiversity of eukaryotic plankton community was significantly higher in the seaweed cultivation area than that in the nearby control area as reflected in OTU richness, evenness (Shannon-Wiener index) and dominance (Simpson index) for total plankton community and its four subcategories when Gracilaria biomass reached the maximum, while no such a significant difference was observed before seaweed inoculation. Our laboratory experiment using an artificial phytoplankton community of nine species observed the same effects of Gracilaria exposure. Principal component analysis and principal coordinates analysis showed the plankton community structure in cultivation area markedly differed from the control area when Gracilaria biomass reached its maximum. Redundancy analysis showed that G. lemaneiformis was the critical factor in controlling the dynamics of eukaryotic plankton communities in the studied coastal ecosystem. Our results explicitly demonstrated G. lemaneiformis cultivation could enhance biodiversity of plankton community via allelopathy, which prevents one or several plankton species from blooming and consequently maintains a relatively higher biodiversity. Our study provided further support for using large-scale G. lemaneiformis cultivation as an effective approach for improving costal ecosystem health. © 2018 John Wiley & Sons Ltd.

  4. Biodiversity effects on resource use efficiency and community turnover of plankton in Lake Nansihu, China.

    Science.gov (United States)

    Tian, Wang; Zhang, Huayong; Zhang, Jian; Zhao, Lei; Miao, Mingsheng; Huang, Hai

    2017-04-01

    The relationship between biodiversity and ecosystem functioning is a central issue in ecology, especially in aquatic ecosystems due to the ecophysiological characteristics of plankton. Recently, ecologists have obtained conflicting conclusions while analyzing the influence of species diversity on plankton resource use efficiency (RUE) and community turnover. In this study, both phytoplankton and zooplankton communities were investigated seasonally from 2011 to 2013 in Lake Nansihu, a meso-eutrophic and recovering lake in China. The effects of phytoplankton diversity on RUE of phytoplankton (RUE PP ), zooplankton (RUE ZP ), and community turnover were analyzed. Results showed that both phytoplankton species richness and evenness were positively correlated with RUE PP . RUE ZP had a negative relationship with phytoplankton species richness, but a weak unimodal relationship with phytoplankton evenness. Cyanobacteria community had the opposite influence on RUE PP and RUE ZP . Thus, cyanobacteria dominance will benefit RUE PP in eutrophic lakes, but the growth and reproduction of zooplankton are greatly limited. The strong negative relationship between total phosphorus and RUE ZP confirmed these results. Phytoplankton community turnover tended to decrease with increasing phytoplankton evenness, which was consistent with most previous studies. The correlation coefficient between phytoplankton species richness and community turnover was negative, but not significant (p > 0.05). Therefore, phytoplankton community turnover was more sensitive to the variation of evenness than species richness. These results will be helpful in understanding the effects of species diversity on ecosystem functioning in aquatic ecosystems.

  5. Tintinnid ciliates of Amundsen Sea (Antarctica plankton communities

    Directory of Open Access Journals (Sweden)

    John R. Dolan

    2013-05-01

    Full Text Available The Amundsen Sea has been described as one of the most productive and dynamic pelagic systems in Antarctica and is one of the least studied. Based on samples from 15 stations in the Amundsen Sea, we describe for the first time the composition of the tintinnid ciliate assemblage of the microzooplankton. We compared the species compositions of coastal polynya sites, where the phytoplankton communities are dominated by Phaeocystis, to those of the offshore deep water sites, which are dominated by diatoms. We found a total of 15 species. Polynya sites were dominated by a few species of tintinnids, mostly those endemic to the Southern Ocean. In contrast, the deep-water sites contained many widespread tintinnid species, which are known from a wide variety of systems as well as other areas of the Southern Ocean. We examined polymorphism known to characterize the Antarctic tintinnid species Cymatocylis affinis/convallaria and Codonellopsis gaussi. We found that the types or forms found appeared unrelated to the type of microplankton community, defined by the identity of the dominant phytoplankton taxa. However, the number of different morphotypes found at a site appeared related to the overall concentration of the species, suggesting that different morphologies, previously considered distinct species, may simply be developmental stages.

  6. Influence of plankton community structure on the sinking velocity of marine aggregates

    Science.gov (United States)

    Bach, L. T.; Boxhammer, T.; Larsen, A.; Hildebrandt, N.; Schulz, K. G.; Riebesell, U.

    2016-08-01

    About 50 Gt of carbon is fixed photosynthetically by surface ocean phytoplankton communities every year. Part of this organic matter is reprocessed within the plankton community to form aggregates which eventually sink and export carbon into the deep ocean. The fraction of organic matter leaving the surface ocean is partly dependent on aggregate sinking velocity which accelerates with increasing aggregate size and density, where the latter is controlled by ballast load and aggregate porosity. In May 2011, we moored nine 25 m deep mesocosms in a Norwegian fjord to assess on a daily basis how plankton community structure affects material properties and sinking velocities of aggregates (Ø 80-400 µm) collected in the mesocosms' sediment traps. We noted that sinking velocity was not necessarily accelerated by opal ballast during diatom blooms, which could be due to relatively high porosity of these rather fresh aggregates. Furthermore, estimated aggregate porosity (Pestimated) decreased as the picoautotroph (0.2-2 µm) fraction of the phytoplankton biomass increased. Thus, picoautotroph-dominated communities may be indicative for food webs promoting a high degree of aggregate repackaging with potential for accelerated sinking. Blooms of the coccolithophore Emiliania huxleyi revealed that cell concentrations of 1500 cells/mL accelerate sinking by about 35-40%, which we estimate (by one-dimensional modeling) to elevate organic matter transfer efficiency through the mesopelagic from 14 to 24%. Our results indicate that sinking velocities are influenced by the complex interplay between the availability of ballast minerals and aggregate packaging; both of which are controlled by plankton community structure.

  7. Community barcoding reveals little effect of ocean acidification on the composition of coastal plankton communities: Evidence from a long-term mesocosm study in the Gullmar Fjord, Skagerrak.

    Directory of Open Access Journals (Sweden)

    Julia A F Langer

    Full Text Available The acidification of the oceans could potentially alter marine plankton communities with consequences for ecosystem functioning. While several studies have investigated effects of ocean acidification on communities using traditional methods, few have used genetic analyses. Here, we use community barcoding to assess the impact of ocean acidification on the composition of a coastal plankton community in a large scale, in situ, long-term mesocosm experiment. High-throughput sequencing resulted in the identification of a wide range of planktonic taxa (Alveolata, Cryptophyta, Haptophyceae, Fungi, Metazoa, Hydrozoa, Rhizaria, Straminipila, Chlorophyta. Analyses based on predicted operational taxonomical units as well as taxonomical compositions revealed no differences between communities in high CO2 mesocosms (~ 760 μatm and those exposed to present-day CO2 conditions. Observed shifts in the planktonic community composition were mainly related to seasonal changes in temperature and nutrients. Furthermore, based on our investigations, the elevated CO2 did not affect the intraspecific diversity of the most common mesozooplankter, the calanoid copepod Pseudocalanus acuspes. Nevertheless, accompanying studies found temporary effects attributed to a raise in CO2. Differences in taxa composition between the CO2 treatments could, however, only be observed in a specific period of the experiment. Based on our genetic investigations, no compositional long-term shifts of the plankton communities exposed to elevated CO2 conditions were observed. Thus, we conclude that the compositions of planktonic communities, especially those in coastal areas, remain rather unaffected by increased CO2.

  8. Community barcoding reveals little effect of ocean acidification on the composition of coastal plankton communities: Evidence from a long-term mesocosm study in the Gullmar Fjord, Skagerrak.

    Science.gov (United States)

    Langer, Julia A F; Sharma, Rahul; Schmidt, Susanne I; Bahrdt, Sebastian; Horn, Henriette G; Algueró-Muñiz, María; Nam, Bora; Achterberg, Eric P; Riebesell, Ulf; Boersma, Maarten; Thines, Marco; Schwenk, Klaus

    2017-01-01

    The acidification of the oceans could potentially alter marine plankton communities with consequences for ecosystem functioning. While several studies have investigated effects of ocean acidification on communities using traditional methods, few have used genetic analyses. Here, we use community barcoding to assess the impact of ocean acidification on the composition of a coastal plankton community in a large scale, in situ, long-term mesocosm experiment. High-throughput sequencing resulted in the identification of a wide range of planktonic taxa (Alveolata, Cryptophyta, Haptophyceae, Fungi, Metazoa, Hydrozoa, Rhizaria, Straminipila, Chlorophyta). Analyses based on predicted operational taxonomical units as well as taxonomical compositions revealed no differences between communities in high CO2 mesocosms (~ 760 μatm) and those exposed to present-day CO2 conditions. Observed shifts in the planktonic community composition were mainly related to seasonal changes in temperature and nutrients. Furthermore, based on our investigations, the elevated CO2 did not affect the intraspecific diversity of the most common mesozooplankter, the calanoid copepod Pseudocalanus acuspes. Nevertheless, accompanying studies found temporary effects attributed to a raise in CO2. Differences in taxa composition between the CO2 treatments could, however, only be observed in a specific period of the experiment. Based on our genetic investigations, no compositional long-term shifts of the plankton communities exposed to elevated CO2 conditions were observed. Thus, we conclude that the compositions of planktonic communities, especially those in coastal areas, remain rather unaffected by increased CO2.

  9. Atmospheric Deposition Effects on Plankton Communities in the Eastern Mediterranean: A Mesocosm Experimental Approach

    Directory of Open Access Journals (Sweden)

    Tatiana M. Tsagaraki

    2017-07-01

    Full Text Available The effects of atmospheric deposition on plankton community structure were examined during a mesocosm experiment using water from the Cretan Sea (Eastern Mediterranean, an area with a high frequency of atmospheric aerosol deposition events. The experiment was carried out under spring-summer conditions (May 2012. The main objective was to study the changes induced from a single deposition event, on the autotrophic and heterotrophic surface microbial populations, from viruses to zooplankton. To this end, the effects of Saharan dust addition were compared to the effects of mixed aerosol deposition on the plankton community over 9 days. The effects of the dust addition seemed to propagate throughout the food-web, with changes observed in nearly all of the measured parameters up to copepods. The dust input stimulated increased productivity, both bacterial and primary. Picoplankton, both autotrophic and heterotrophic capitalized on the changes in nutrient availability and microzooplankton abundance also increased due to increased availability of prey. Five days after the simulated deposition, copepods also responded, with an increase in egg production. The results suggest that nutrients were transported up the food web through autotrophs, which were favored by the Nitrogen supplied through both treatments. Although, the effects of individual events are generally short lived, increased deposition frequency and magnitude of events is expected in the area, due to predicted reduction in rainfall and increase in temperature, which can lead to more persistent changes in plankton community structure. Here we demonstrate how a single dust deposition event leads to enhancement of phytoplankton and microzooplankton and can eventually, through copepods, transport more nutrients up the food web in the Eastern Mediterranean Sea.

  10. Effect of ocean acidification on the fatty acid composition of a natural plankton community

    Directory of Open Access Journals (Sweden)

    E. Leu

    2013-02-01

    Full Text Available The effect of ocean acidification on the fatty acid composition of a natural plankton community in the Arctic was studied in a large-scale mesocosm experiment, carried out in Kongsfjorden (Svalbard, Norway at 79° N. Nine mesocosms of ~50 m3 each were exposed to 8 different pCO2 levels (from natural background conditions to ~1420 μatm, yielding pH values (on the total scale from ~8.3 to 7.5. Inorganic nutrients were added on day 13. The phytoplankton development during this 30-day experiment passed three distinct phases: (1 prior to the addition of inorganic nutrients, (2 first bloom after nutrient addition, and (3 second bloom after nutrient addition. The fatty acid composition of the natural plankton community was analysed and showed, in general, high percentages of polyunsaturated fatty acids (PUFAs: 44–60% of total fatty acids. Positive correlations with pCO2 were found for most PUFAs during phases 2 and/or 3, with the exception of 20:5n3 (eicosapentaenoic acid, EPA, an important diatom marker. These correlations are probably linked to changes in taxonomic composition in response to pCO2. While diatoms (together with prasinophytes and haptophytes increased during phase 3 mainly in the low and intermediate pCO2 treatments, dinoflagellates were favoured by high CO2 concentrations during the same time period. This is reflected in the development of group-specific fatty acid trophic markers. No indications were found for a generally detrimental effect of ocean acidification on the planktonic food quality in terms of essential fatty acids.

  11. Effect of ocean acidification on the fatty acid composition of a natural plankton community

    Science.gov (United States)

    Leu, E.; Daase, M.; Schulz, K. G.; Stuhr, A.; Riebesell, U.

    2013-02-01

    The effect of ocean acidification on the fatty acid composition of a natural plankton community in the Arctic was studied in a large-scale mesocosm experiment, carried out in Kongsfjorden (Svalbard, Norway) at 79° N. Nine mesocosms of ~50 m3 each were exposed to 8 different pCO2 levels (from natural background conditions to ~1420 μatm), yielding pH values (on the total scale) from ~8.3 to 7.5. Inorganic nutrients were added on day 13. The phytoplankton development during this 30-day experiment passed three distinct phases: (1) prior to the addition of inorganic nutrients, (2) first bloom after nutrient addition, and (3) second bloom after nutrient addition. The fatty acid composition of the natural plankton community was analysed and showed, in general, high percentages of polyunsaturated fatty acids (PUFAs): 44-60% of total fatty acids. Positive correlations with pCO2 were found for most PUFAs during phases 2 and/or 3, with the exception of 20:5n3 (eicosapentaenoic acid, EPA), an important diatom marker. These correlations are probably linked to changes in taxonomic composition in response to pCO2. While diatoms (together with prasinophytes and haptophytes) increased during phase 3 mainly in the low and intermediate pCO2 treatments, dinoflagellates were favoured by high CO2 concentrations during the same time period. This is reflected in the development of group-specific fatty acid trophic markers. No indications were found for a generally detrimental effect of ocean acidification on the planktonic food quality in terms of essential fatty acids.

  12. Effects of Bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches

    International Nuclear Information System (INIS)

    Liu, Yongbo; Liu, Fang; Wang, Chao; Quan, Zhanjun; Li, Junsheng

    2016-01-01

    The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch. Cultivation of Bt-transgenic rice had no effects on zooplankton communities. Phytoplankton abundance and biodiversity were not significantly different between transgenic and non-transgenic rice fields in 2013; however, phytoplankton were more abundant in the transgenic rice field than in the non-transgenic rice field in 2014. Water quality and rice type explained 65.9% and 12.8% of this difference in 2014, respectively. Phytoplankton and zooplankton were more abundant in mid- and downstream, than upstream, locations in the ditch, an effect that we attribute to water quality differences. Thus, the release of Bt toxins into field water during the cultivation of transgenic crops had no direct negative effects on plankton community composition, but indirect effects that alter environmental conditions should be taken into account during the processes of management planning and policymaking. - Highlights: • We detect fusion Cry1Ab/1Ac proteins from Bt rice entering into aquatic ecosystems. • Bt-transgenic rice cultivation have no significant effect on zooplankton community. • Bt-transgenic rice cultivation have indirect effect on phytoplankton community. • Water quality explains the difference of plankton communities in adjacent ditches.

  13. Effects of Bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongbo, E-mail: liuyb@craes.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Liu, Fang [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Wang, Chao [Pearl River Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou 510380 (China); Quan, Zhanjun [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Li, Junsheng, E-mail: lijsh@creas.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)

    2016-09-15

    The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch. Cultivation of Bt-transgenic rice had no effects on zooplankton communities. Phytoplankton abundance and biodiversity were not significantly different between transgenic and non-transgenic rice fields in 2013; however, phytoplankton were more abundant in the transgenic rice field than in the non-transgenic rice field in 2014. Water quality and rice type explained 65.9% and 12.8% of this difference in 2014, respectively. Phytoplankton and zooplankton were more abundant in mid- and downstream, than upstream, locations in the ditch, an effect that we attribute to water quality differences. Thus, the release of Bt toxins into field water during the cultivation of transgenic crops had no direct negative effects on plankton community composition, but indirect effects that alter environmental conditions should be taken into account during the processes of management planning and policymaking. - Highlights: • We detect fusion Cry1Ab/1Ac proteins from Bt rice entering into aquatic ecosystems. • Bt-transgenic rice cultivation have no significant effect on zooplankton community. • Bt-transgenic rice cultivation have indirect effect on phytoplankton community. • Water quality explains the difference of plankton communities in adjacent ditches.

  14. Influence of ocean acidification and deep water upwelling on oligotrophic plankton communities in the subtropical North Atlantic

    DEFF Research Database (Denmark)

    Taucher, Jan; Bach, Lennart T.; Boxhammer, Tim

    2017-01-01

    Oceanic uptake of anthropogenic carbon dioxide (CO2) causes pronounced shifts in marine carbonate chemistry and a decrease in seawater pH. Increasing evidence indicates that these changes-summarized by the term ocean acidification (OA)-can significantly affect marine food webs and biogeochemical...... cycles. However, current scientific knowledge is largely based on laboratory experiments with single species and artificial boundary conditions, whereas studies of natural plankton communities are still relatively rare. Moreover, the few existing community-level studies were mostly conducted in rather...... and successfully simulated a deep water upwelling event that induced a pronounced plankton bloom. Our study revealed significant effects of OA on the entire food web, leading to a restructuring of plankton communities that emerged during the oligotrophic phase, and was further amplified during the bloom...

  15. Iron fertilization and the structure of planktonic communities in high nutrient regions of the Southern Ocean

    Science.gov (United States)

    Quéguiner, Bernard

    2013-06-01

    In this review article, plankton community structure observations are analyzed both for artificial iron fertilization experiments and also for experiments dedicated to the study of naturally iron-fertilized systems in the Atlantic, Indian and Pacific sectors of the Southern Ocean in the POOZ (Permanently Open Ocean Zone) and the PFZ (Polar Frontal Zone). Observations made in natural systems are combined with those from artificially perturbed systems, in order to evaluate the seasonal evolution of pelagic communities, taking into account controlling factors related to the life cycles and the ecophysiology of dominant organisms. The analysis considers several types of planktonic communities, including both autotrophs and heterotrophs. These communities are spatially segregated owing to different life strategies. A conceptual general scheme is proposed to account for these observations and their variability, regardless of experiment type. Diatoms can be separated into 2 groups: Group 1 has slightly silicified fast growing cells that are homogeneously distributed in the surface mixed layer, and Group 2 has strongly silicified slowly growing cells within discrete layers. During the growth season, Group 1 diatoms show a typical seasonal succession of dominant species, within time windows of development that are conditioned by physical factors (light and temperature) as well as endogenous specific rhythms (internal clock), and biomass accumulation is controlled by the availability of nutrients. Group 1 diatoms are not directly grazed by mesozooplankton which is fed by protozooplankton, linking the microbial food web to higher trophic levels. Instead, successive dominant species of Group 1 are degraded via bacterial activity at the end of their growth season. Organic detritus fragments feed protozooplankton and mesozooplankton. The effective silicon pump leads to the progressive disappearance of silicic acid in surface waters. In contrast, Group 2 is resistant to grazing

  16. Lack of congruence in species diversity indices and community structures of planktonic groups based on local environmental factors.

    Science.gov (United States)

    Doi, Hideyuki; Chang, Kwang-Hyeon; Nishibe, Yuichiro; Imai, Hiroyuki; Nakano, Shin-ichi

    2013-01-01

    The importance of analyzing the determinants of biodiversity and community composition by using multiple trophic levels is well recognized; however, relevant data are lacking. In the present study, we investigated variations in species diversity indices and community structures of the plankton taxonomic groups-zooplankton, rotifers, ciliates, and phytoplankton-under a range of local environmental factors in pond ecosystems. For each planktonic group, we estimated the species diversity index by using linear models and analyzed the community structure by using canonical correspondence analysis. We showed that the species diversity indices and community structures varied among the planktonic groups and according to local environmental factors. The observed lack of congruence among the planktonic groups may have been caused by niche competition between groups with similar trophic guilds or by weak trophic interactions. Our findings highlight the difficulty of predicting total biodiversity within a system, based upon a single taxonomic group. Thus, to conserve the biodiversity of an ecosystem, it is crucial to consider variations in species diversity indices and community structures of different taxonomic groups, under a range of local conditions.

  17. The effects of ultraviolet radiation on the planktonic community of a shallow, eutrophic estuary: results of mesocosm experiments

    NARCIS (Netherlands)

    Forster, R.M.; Schubert, H.

    2001-01-01

    This paper describes the results of pelagic mesocosm experiments designed to test the effects of enhanced and reduced ultraviolet radiation (UV) on the planktonic community of a Baltic Sea estuary. The Darss-Zingst estuary consists of a series of brackish lagoons with high concentrations of

  18. Influence of water mixing and food web status on the response of planktonic communities to enhanced ultraviolet-B radiation

    Science.gov (United States)

    Mostajir, B.; Uvbr Team

    2003-04-01

    Two series of mesocosm experiments were carried out in 1996 and 1997 using the natural planktonic assemblage, ultraviolet-B radiation (UVBR: 280-320 nm) at the community level. The water used in the first experiment was rich in nitrate (ca. 8-10 μM) and phytoplankton biomass (5 μg Chlorophyll a L-1: Chl a), conditions typical of an eutrophic coastal zone with herbivorous food web characteristics. In contrast, the water used in the second experiment was poor in nitrate (food web. Furthermore, to understand the influence of vertical mixing on the effects of UVBR on the planktonic community, two mixing regimes (fast and slow) were tested during the mesocosm experiments of 1997. The results showed that the mixing regime can moderate the effects of UVBR on the planktonic community and can also modify completely the species composition in the mesocosms much more than the UVBR. Comparison between the impact of UVBR on the planktonic community presented in these two experiments suggested that regenerated production-based systems (e.g. microbial food webs) tolerate the effects of UVBR more efficiently than do new production-based systems (herbivorous food webs). Results regarding the potential effects of UVBR in different marine systems, coastal versus oceanic, where different physical systems dominate, fast versus slow mixing, and consequently the development of different food webs are favored, herbivorous versus microbial, will be discussed.

  19. High resilience of two coastal plankton communities to 21st century seawater acidification: Evidence from microcosm studies

    DEFF Research Database (Denmark)

    Nielsen, Lasse Tor; Jakobsen, Hans Henrik; Hansen, Per Juul

    2010-01-01

    Increased free CO2 and ocean acidification are among the consequences of anthropogenic carbon emissions. Responses of marine protists to increased levels of CO2 are highly species-specific, and this has been suggested to cause an alteration in plankton species composition, community functions...

  20. Differences in carbohydrate profiles in batch culture grown planktonic and biofilm cells of Amphora rostrata Wm. Sm

    Digital Repository Service at National Institute of Oceanography (India)

    Khodse, V.B.; Bhosle, N.B.

    material in the central equatorial Pacific. Deep-Sea Res I 43:1181-1204. Hitchcock GL. 1977. The concentration of particulate carbohydrates in a region of the West Africa upwelling zone during March 1974. Deep-Sea Res 24:83-93. Hoagland KD, Rosowski JR... and Biochemistry, IIB. Academic Press, London, pp 537-568 Roszkowski W, Beuth J, Ko HL, Uhlenbruck G, Pulverer G. 1989. Blocking of lectin like adhesion molecules on pulmonary cells inhibits lung sarcoma L colonization in BALB/c-mice. Experientia 45...

  1. Microbial plankton communities in the coastal southeastern Black Sea: biomass, composition and trophic interactions

    Directory of Open Access Journals (Sweden)

    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

  2. Plankton community structure and connectivity in the Kimberley-Browse region of NW Australia

    Science.gov (United States)

    McKinnon, A. D.; Duggan, S.; Holliday, D.; Brinkman, R.

    2015-02-01

    We describe the zooplankton and ichthyoplankton communities of coastal waters of the Kimberley coast (North West Australia), sampled in macrotidal Camden Sound during both the wet and dry seasons of 2011, and compare these to six other Kimberley embayments during the wet season of 2013. Zooplankton abundance in Camden Sound was 7038 ± 3913 SD ind. m-3 in the wet season and 1892 ± 708 SD ind. m-3 in the dry season, with copepods accounting for 85% by number. In all, 78 species of copepods were recorded, with the families Paracalanidae and Oithonidae dominant. In Camden Sound, 48 families of larval fish occurred, with ichthyoplankton more abundant in the wet season than the dry season (1.16 ± 0.2 ind. m-3 cf 0.76 ± 0.2 ind. m-3). Larval gobiids (Subfamily Gobiinae) were most abundant, with other common families associated with either pelagic or soft-bottom habitats as adults. Multivariate analyses of both copepod and ichthyoplankton communities demonstrated strong seasonal contrasts, although an along-shelf gradient in copepod community composition was apparent along the embayments sampled in 2013. There was little spatial variation in plankton communities within Camden Sound as a result of the large tidal range (up to 11.7 m, with 2.5 m-1 velocities), although gradients in abundance and composition on cross-shelf transects occurred in the more northern embayments that had a lower tidal range, such as Napier Broome Bay. Copepod communities of the Kimberley-Browse region were placed in regional perspective by multivariate analyses of similar data collected in the eastern Indian Ocean at Scott Reef, in the Arafura Sea and on the southern North West (NW) shelf. The plankton communities of the NW shelf form a series of along-shore metacommunities linked by advection, with weaker cross-shelf connectivity. The presence of the larvae of mesopelagic fishes of the family Myctophidae in coastal waters confirms seasonal cross-shelf connectivity.

  3. Production and decomposition of new DOC by marine plankton communities: carbohydrates, refractory components and nutrient limitation

    DEFF Research Database (Denmark)

    Kragh, T.; Søndergaard, Morten

    2009-01-01

    The accumulation and biodegradation of dissolved organic carbon (DOC) and dissolved and particulate combined neutral sugars (DCNS, PCNS) were followed during a period of 22 days in experimental marine phytoplankton incubations. Five different growth regimes were established in 11 m(3) coastal...... in the mesocosms with diatoms dominating could be explained by DCNS, while only 6% was explained in the mesocosms with few diatoms. PCNS composition was similar in all mesocosms and with dominance of glucose and mannose, while DCNS were more evenly distributed with the following mole percentages fucose 15......, rhamnose 14, arabinose 6, galactose 27, glucose 20 and mannose 18%. The DCNS composition did not reflect the PCNS composition at any time during the experiment. Accumulated DCNS were quickly degraded and only 1% of the new RDOC was explained by DCNS. RDOC accumulated after day #17 in the two mesocosms...

  4. Effects on the function of three trophic levels in marine plankton communities under stress from the antifouling compound zinc pyrithione

    International Nuclear Information System (INIS)

    Hjorth, M.; Dahlloef, I.; Forbes, V.E.

    2006-01-01

    This study aimed to investigate functional responses of natural marine planktonic communities to stress from the antifouling compound zinc pyrithione (ZPT). Isotope labelling techniques ( 14 C) were applied to study bacterial incorporation of leucine, photosynthetic activity of phytoplankton and grazing of labelled prey by zooplankton communities for 6 days after exposures to nominal concentrations of 0, 5, 25, 50 nM ZPT in a mesocosm experiment in Isefjord, Denmark. Significant direct effects were visible on chlorophyll a concentrations, which decreased in all exposed communities, to between 48 and 36% of control concentrations on Day 3, 1 day after the last exposure. Phytoplankton activities were also significantly affected on Day 3 with activities between 9 and 26% of control levels, as was zooplankton activities in the 25 and 50 nM exposures. In the 50 nM exposure the total community zooplankton activity was reduced to 25 ± 4%, and per individual to 46 ± 11% of control levels. Bacterial communities showed positive indirect effects with high activities (up to 183 ± 40%) due to higher amounts of available substrate from algal death. Pollution induced community tolerance analyses performed on phytoplankton and bacterial communities at the end of the experiment indicated a development of increased tolerance for phytoplankton in the 50 nM exposed communities, whereas there were no changes in tolerance in the bacterial communities. Multivariate analysis of the integrated functional response by the plankton communities revealed a significant difference (p < 0.05) between exposed communities compared to controls in the first 3 days after last exposure and in the end of the experiment. The study provides evidence of diverse effects on the functions of marine plankton communities under stress from a pollutant. Direct effects lead to cascading indirect effects throughout the community, eventually causing different developments. Continuous exposure to ZPT could lead to

  5. Differences in plankton community structure and carbon cycling along a climate gradient from the Greenland Ice Sheet to offshore waters

    DEFF Research Database (Denmark)

    Arendt, K.E.; Nielsen, Torkel Gissel; Rysgaard, S.

    Huge differences in plankton community structures and biomasses are observed along a climate gradient from the Greenland Ice Sheet to offshore waters at the West Greenland coast. The offshore region has a high biomass of copepods dominated by Calanus spp., which are capable of consuming 55....... Protozooplankton accounts for 20-38% of the carbon turnover in the offshore and inland areas. However, protozooplankton like copepods has low ability to turn over the primary production close to the Ice Sheet. Increased run of from the Greenland Ice Sheet due to global warming could displace the existing climate...... gradient. This would have a profound influence on the future plankton community structure as well as the energy transfer to higher trophic levels in Arctic coastal ecosystems....

  6. Temperature dependence of plankton community metabolism in the subtropical and tropical oceans

    KAUST Repository

    Garcia-Corral, Lara S.; Holding, Johnna M.; Carrillo-de-Albornoz, Paloma; Steckbauer, Alexandra; Pé rez-Lorenzo, Marí a; Navarro, Nuria; Serret, Pablo; Gasol, Josep M.; Moran, Xose Anxelu G.; Estrada, Marta; Fraile-Nuez, Eugenio; Bení tez-Barrios, Veró nica; Agusti, Susana; Duarte, Carlos M.

    2017-01-01

    Here we assess the temperature dependence of the metabolic rates (gross primary production (GPP), community respiration (CR), and the ratio GPP/CR) of oceanic plankton communities. We compile data from 133 stations of the Malaspina 2010 Expedition, distributed among the subtropical and tropical Atlantic, Pacific, and Indian oceans. We used the in vitro technique to measured metabolic rates during 24 h incubations at three different sampled depths: surface, 20%, and 1% of the photosynthetically active radiation measured at surface. We also measured the % of ultraviolet B radiation (UVB) penetrating at surface waters. GPP and CR rates increased with warming, albeit different responses were observed for each sampled depth. The overall GPP/CR ratio declined with warming. Higher activation energies (E-a) were derived for both processes (GPP(Chla) = 0.97; CRChla = 1.26; CRHPA = 0.95 eV) compared to those previously reported. The Indian Ocean showed the highest E-a (GPP(Chla) = 1.70; CRChla = 1.48; CRHPA = 0.57 eV), while the Atlantic Ocean showed the lowest (GPP(Chla) = 0.86; CRChla = 0.77; CRHPA = -0.13 eV). We believe that the difference between previous assessments and the ones presented here can be explained by the overrepresentation of Atlantic communities in the previous data sets. We found that UVB radiation also affects the temperature dependence of surface GPP, which decreased rather than increased under high levels of UVB. Ocean warming, which causes stratification and oligotrophication of the subtropical and tropical oceans, may lead to reduced surface GPP as a result of increased penetration of UVB radiation.

  7. Temperature dependence of plankton community metabolism in the subtropical and tropical oceans

    KAUST Repository

    Garcia-Corral, Lara S.

    2017-06-22

    Here we assess the temperature dependence of the metabolic rates (gross primary production (GPP), community respiration (CR), and the ratio GPP/CR) of oceanic plankton communities. We compile data from 133 stations of the Malaspina 2010 Expedition, distributed among the subtropical and tropical Atlantic, Pacific, and Indian oceans. We used the in vitro technique to measured metabolic rates during 24 h incubations at three different sampled depths: surface, 20%, and 1% of the photosynthetically active radiation measured at surface. We also measured the % of ultraviolet B radiation (UVB) penetrating at surface waters. GPP and CR rates increased with warming, albeit different responses were observed for each sampled depth. The overall GPP/CR ratio declined with warming. Higher activation energies (E-a) were derived for both processes (GPP(Chla) = 0.97; CRChla = 1.26; CRHPA = 0.95 eV) compared to those previously reported. The Indian Ocean showed the highest E-a (GPP(Chla) = 1.70; CRChla = 1.48; CRHPA = 0.57 eV), while the Atlantic Ocean showed the lowest (GPP(Chla) = 0.86; CRChla = 0.77; CRHPA = -0.13 eV). We believe that the difference between previous assessments and the ones presented here can be explained by the overrepresentation of Atlantic communities in the previous data sets. We found that UVB radiation also affects the temperature dependence of surface GPP, which decreased rather than increased under high levels of UVB. Ocean warming, which causes stratification and oligotrophication of the subtropical and tropical oceans, may lead to reduced surface GPP as a result of increased penetration of UVB radiation.

  8. Interacting growth and loss rates: The balance of top-down and bottom-up controls in plankton communities

    International Nuclear Information System (INIS)

    Lehman, J.T.

    1991-01-01

    Application of resource-based competition theory to high-nutrient, low-chlorophyll regions of the ocean suggests that single-factor controls on vertical export rates of carbon from euphotic zones are unlikely. High specific rates of grazing or sinking losses interact with growth physiology to produce nutrient requirements in situ that are much higher than those required for the growth of populations held in bottle bioassays. The efficiency of vertical export of carbon by sinking particulates can vary with species composition of the plankton, which in turn can be altered by nutrient manipulation. A simulation model explores possible changes to species composition and vertical carbon flux which might result from addition of Fe to Southern Ocean plankton communities. Nutrient manipulation permits invasion of plankton communities by taxa not originally present and does not necessarily increase the biomass or metabolism of resident species. This makes a priori prediction of fluxes associated with an enriched and altered community fundamentally uncertain if predictions are based on stoichiometries and physiologies of the original resident taxa. Vertical carbon flux could either increase or decrease in response to single-element addition, depending on the attributes of the invading species

  9. Role of Fusobacterium nucleatum and Coaggregation in Anaerobe Survival in Planktonic and Biofilm Oral Microbial Communities during Aeration

    Science.gov (United States)

    Bradshaw, David J.; Marsh, Philip D.; Watson, G. Keith; Allison, Clive

    1998-01-01

    Coaggregation is a well-characterized phenomenon by which specific pairs of oral bacteria interact physically. The aim of this study was to examine the patterns of coaggregation between obligately anaerobic and oxygen-tolerant species that coexist in a model oral microbial community. Obligate anaerobes other than Fusobacterium nucleatum coaggregated only poorly with oxygen-tolerant species. In contrast, F. nucleatum was able to coaggregate not only with both oxygen-tolerant and other obligately anaerobic species but also with otherwise-noncoaggregating obligate anaerobe–oxygen-tolerant species pairs. The effects of the presence or absence of F. nucleatum on anaerobe survival in both the biofilm and planktonic phases of a complex community of oral bacteria grown in an aerated (gas phase, 200 ml of 5% CO2 in air · min−1) chemostat system were then investigated. In the presence of F. nucleatum, anaerobes persisted in high numbers (>107 · ml−1 in the planktonic phase and >107 · cm−2 in 4-day biofilms). In an equivalent culture in the absence of F. nucleatum, the numbers of black-pigmented anaerobes (Porphyromonas gingivalis and Prevotella nigrescens) were significantly reduced (P ≤ 0.001) in both the planktonic phase and in 4-day biofilms, while the numbers of facultatively anaerobic bacteria increased in these communities. Coaggregation-mediated interactions between F. nucleatum and other species facilitated the survival of obligate anaerobes in aerated environments. PMID:9746571

  10. Impact of multispecies diatom bloom on plankton community structure in Sundarban mangrove wetland, India

    International Nuclear Information System (INIS)

    Biswas, Sejuti Naha; Rakshit, Dibyendu; Sarkar, Santosh Kumar; Sarangi, Ranjit Kumar; Satpathy, Kamala Kanta

    2014-01-01

    Highlights: • A multispecies algal bloom was studied in coastal regions of Sundarban wetland. • Sharp changes in plankton community structure and hydrological parameters observed. • Chlorophyll a showed highest cell density (11.4 × 10 5 cells l −1 ) during bloom phase. • MODIS Aqua derived chlorophyll maps have been interpreted. - Abstract: A multispecies bloom caused by the centric diatoms, viz. Coscinodiscus radiatus, Chaetoceros lorenzianus and the pennate diatom Thalassiothrix frauenfeldii was investigated in the context of its impact on phytoplankton and microzooplankton (the loricate ciliate tintinnids) in the coastal regions of Sagar Island, the western part of Sundarban mangrove wetland, India. Both number (15–18 species) and cell densities (12.3 × 10 3 cells l −1 to 11.4 × 10 5 cells l −1 ) of phytoplankton species increased during peak bloom phase, exhibiting moderately high species diversity (H′ = 2.86), richness (R′ = 6.38) and evenness (E′ = 0.80). The diatom bloom, which existed for a week, had a negative impact on the tintinnid community in terms of drastic changes in species diversity index (1.09–0.004) and population density (582.5 × 10 3 to 50 × 10 3 ind m −3 ). The bloom is suggested to have been driven by the aquaculture activities and river effluents resulting high nutrient concentrations in this region. An attempt has been made to correlate the satellite remote sensing-derived information to the bloom conditions. MODIS-Aqua derived chlorophyll maps have been interpreted

  11. Community structure and function of planktonic Crenarchaeota: changes with depth in the South China Sea.

    Science.gov (United States)

    Hu, Anyi; Jiao, Nianzhi; Zhang, Chuanlun L

    2011-10-01

    Marine Crenarchaeota represent a widespread and abundant microbial group in marine ecosystems. Here, we investigated the abundance, diversity, and distribution of planktonic Crenarchaeota in the epi-, meso-, and bathypelagic zones at three stations in the South China Sea (SCS) by analysis of crenarchaeal 16S rRNA gene, ammonia monooxygenase gene amoA involved in ammonia oxidation, and biotin carboxylase gene accA putatively involved in archaeal CO(2) fixation. Quantitative PCR analyses indicated that crenarchaeal amoA and accA gene abundances varied similarly with archaeal and crenarchaeal 16S rRNA gene abundances at all stations, except that crenarchaeal accA genes were almost absent in the epipelagic zone. Ratios of the crenarchaeal amoA gene to 16S rRNA gene abundances decreased ~2.6 times from the epi- to bathypelagic zones, whereas the ratios of crenarchaeal accA gene to marine group I crenarchaeal 16S rRNA gene or to crenarchaeal amoA gene abundances increased with depth, suggesting that the metabolism of Crenarchaeota may change from the epi- to meso- or bathypelagic zones. Denaturing gradient gel electrophoresis profiling of the 16S rRNA genes revealed depth partitioning in archaeal community structures. Clone libraries of crenarchaeal amoA and accA genes showed two clusters: the "shallow" cluster was exclusively derived from epipelagic water and the "deep" cluster was from meso- and/or bathypelagic waters, suggesting that niche partitioning may take place between the shallow and deep marine Crenarchaeota. Overall, our results show strong depth partitioning of crenarchaeal populations in the SCS and suggest a shift in their community structure and ecological function with increasing depth.

  12. Spatial distribution of planktonic bacterial and archaeal communities in the upper section of the tidal reach in Yangtze River

    Science.gov (United States)

    Fan, Limin; Song, Chao; Meng, Shunlong; Qiu, Liping; Zheng, Yao; Wu, Wei; Qu, Jianhong; Li, Dandan; Zhang, Cong; Hu, Gengdong; Chen, Jiazhang

    2016-01-01

    Bacterioplankton and archaeaplankton communities play key roles in the biogeochemical processes of water, and they may be affected by many factors. In this study, we used high-throughput 16S rRNA gene sequencing to profile planktonic bacterial and archaeal community compositions in the upper section of the tidal reach in Yangtze River. We found that the predominant bacterial phyla in this river section were Proteobacteria, Firmicutes, and Actinobacteria, whereas the predominant archaeal classes were Halobacteria, Methanomicrobia, and unclassified Euryarchaeota. Additionally, the bacterial and archaeal community compositions, richnesses, functional profiles, and ordinations were affected by the spatial heterogeneity related to the concentration changes of sulphate or nitrate. Notably, the bacterial community was more sensitive than the archaeal community to changes in the spatial characteristics of this river section. These findings provide important insights into the distributions of bacterial and archaeal communities in natural water habitats. PMID:27966673

  13. Determining Microeukaryotic Plankton Community around Xiamen Island, Southeast China, Using Illumina MiSeq and PCR-DGGE Techniques.

    Directory of Open Access Journals (Sweden)

    Lingyu Yu

    Full Text Available Microeukaryotic plankton are important components of aquatic environments and play key roles in marine microbial food webs; however, little is known about their genetic diversity in subtropical offshore areas. Here we examined the community composition and genetic diversity of the microeukaryotic plankton in Xiamen offshore water by PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis, clone-based sequencing and Illumina based sequencing. The Illumina MiSeq sequencing revealed a much (approximately two orders of magnitude higher species richness of the microeukaryotic community than DGGE, but there were no significant difference in species richness and diversity among the northern, eastern, southern or western stations based on both methods. In this study, Copepoda, Ciliophora, Chlorophyta, Dinophyceae, Cryptophyta and Bacillariophyta (diatoms were the dominant groups even though diatoms were not detected by DGGE. Our Illumina based results indicated that two northern communities (sites N2 and N3 were significantly different from others in having more protozoa and fewer diatoms. Redundancy analysis (RDA showed that both temperature and salinity were the significant environmental factors influencing dominant species communities, whereas the full microeukaryotic community appeared to be affected by a complex of environmental factors. Our results suggested that extensive sampling combined with more deep sequencing are needed to obtain the complete diversity of the microeukaryotic community, and different diversity patterns for both abundant and rare taxa may be important in evaluating the marine ecosystem health.

  14. Effects of the global changes on the aquatic ecosystems in West Europe - role of the plankton communities

    International Nuclear Information System (INIS)

    Souissi, S.

    2007-01-01

    Examination of long-term records of aquatic ecosystems has provided useful information to find out their major driving forces. Understanding the impact of climate change on these ecosystems, the management of their resources and the extrapolation between sites are the main scopes of actual and emerging studies. Such goals can be achieved by inter-site and inter-ecosystem comparisons. This approach was undertaken during our project which has the originality to tackle with marine and freshwater ecosystems. It allowed us to compile and validate several multi-decadal time series of planktonic and other physical driving forces at local and regional scales. Then, the same methodology based on the analysis of the variability of climate indices and biological data across several spatial scales was used. The different ecosystems analyzed here showed clear response to the North Atlantic climate variability. Although the local differences abrupt changes in community composition occurred in all ecosystems in the middle of the years 80. During this period there was also a major shift in climatic conditions during winter and early spring, suggesting an impact of climatic factors. Phenological changes were also observed in plankton communities in all sites. The consequences of the modifications of plankton dynamics on higher trophic levels were also showed. Fluctuations in plankton have resulted in long-term changes in cod recruitment in the North Sea (bottom-up control). On the other hand, both climate change and the improvement of trophic status in Geneva Lake favored the outbreak of whitefish during the years 90. Lower larval mortality and better recruitment are supposed to be linked to faster growth associated with warmer temperatures and better food conditions induced by better temporal overlap between larvae hatching and zooplankton development. (author)

  15. ABUNDANCE AND ISOTOPIC COMPOSITION OF PLANKTONIC MICROCRUSTACEANS IN A CENTRAL AMAZON FLOODPLAIN LAKE: IMPLICATIONS FOR THE TROPHIC DYNAMICS OF THE PLANKTON COMMUNITY

    Directory of Open Access Journals (Sweden)

    Pedro Caraballo

    2016-01-01

    Full Text Available During the hydrological year from December 2007 to November 2008, monthly samplings in the pelagic, littoral and macrophytes zones were conducted in the Lago Catalão, a floodplain lake receiving a mixture of water from Negro and Solimões Rivers, in front of Manaus city. Taxonomic composition and their relative abundance of the planktonic microcrustaceans community was studied. Natural abundances of carbon (C and nitrogen (N stable isotopes were measured to indicate energy sources. Cladocerans were the most abundant, with a relative abundance of 60%, followed by the calanoid and cyclopoid copepods with relative abundances of 29% and 11%, respectively. Diaphanosoma spp. was the dominant cladoceran group during all the sampling periods. Cladocerans were also represented by Moina spp., Ceriodaphnia spp. and Daphnia gessneri. Three genera of calanoid copepods were found: Notodiaptomus spp, Rhacodiaptomus spp., and Argyrodiaptomus spp. The genus Mesocyclops spp. was identified among the cyclopoid copepods. Zooplankton δ13C values indicated that the aquatic macrophyte zone was distinct, with a mean of -27.31‰, which was more enriched than zooplankton in the pelagic and littoral zones, where they had mean δ13C values of -33.11 and -34.66‰, respectively. Overall, analysis of stable isotopes showed that regardless of the pathways, the initial source of carbon for the zooplankton was phytoplankton, with a minimal participation of heterotrophic bacteria.

  16. Planktonic copepod community in the neritic area south western part of Tunis bay influenced by Meliane river supplies (south western Mediterranean sea)

    OpenAIRE

    Ben Lamine, Y.; Daly Yahia Kefi, O.; Daly Yahia, N.

    2012-01-01

    The Tunis bay is located in the North Estern coast of Tunisia and receives in its Western part flows from Meliane River. Our study aims to describe the composition and the spatiotemporal distribution of planktonic copepods in the bay in order to identify the effect of the Meliane River supplies on the community. A grid of 19 stations was investigated monthly from July 2004 to December 2004 using a 160 μm mesh size plankton net, towed obliquely from the bottom to the surface. The planktonic co...

  17. [Changes in phytoperiphyton community during seasonal succession: influence of plankton sedimentation and grazing by phytophages--Chironomid larvae].

    Science.gov (United States)

    Lukin, V B

    2002-01-01

    The investigation of seasonal changes in spatial structure of phytoperiphyton during succession was conducted at the lower reaches of Akulovsky water channel from April to August 2000. At the beginning of succession from April to June dominant forms were chain-forming diatoms and filamentous green algae, sedimented from plankton. Later, at the middle of June under increasing pressure of herbivorous, they were replaced by stretched unicellular diatoms and colonial cyanobacteria. In late June-August, when herbivorous predation was the most intensive, the relative abundance of typical periphytonic forms decreased while that of settled planktonic forms increased. The effect of planktonic algae sedimentation on periphyton composition was evaluated as similarity between phytoperiphyton and phytoplankton communities measured with Chekanovski--Sorensen index. The value of this index tends to decrease with the development of periphyton while showing some relation to intensity of herbivorous pressure. Minimal values of Chekanovski--Sorensen index were under moderate herbivorous density, whereas maximal values were observed in periods of extremely high or low herbivorous density.

  18. Effect of ocean warming and acidification on a plankton community in the NW Mediterranean Sea

    NARCIS (Netherlands)

    Maugendre, L.; Gattuso, J.-P.; Louis, J.; de Kluijver, A.; Marro, S.; Soetaert, K.; Gazeau, F.

    2015-01-01

    The effect of ocean warming and acidification was investigated on a natural plankton assemblage from an oligotrophic area, the bay of Villefranche (NW Mediterranean Sea). The assemblage was sampled in March 2012 and exposed to the following four treatments for 12 days: control (~360 µatm, 14°C),

  19. A 13C labelling study on carbon fluxes in Arctic plankton communities under elevated CO2 levels

    Directory of Open Access Journals (Sweden)

    A. de Kluijver

    2013-03-01

    Full Text Available The effect of CO2 on carbon fluxes (production, consumption, and export in Arctic plankton communities was investigated during the 2010 EPOCA (European project on Ocean Acidification mesocosm study off Ny Ålesund, Svalbard. 13C labelled bicarbonate was added to nine mesocosms with a range in pCO2 (185 to 1420 μatm to follow the transfer of carbon from dissolved inorganic carbon (DIC into phytoplankton, bacterial and zooplankton consumers, and export. A nutrient–phytoplankton–zooplankton–detritus model amended with 13C dynamics was constructed and fitted to the data to quantify uptake rates and carbon fluxes in the plankton community. The plankton community structure was characteristic for a post-bloom situation and retention food web and showed high bacterial production (∼31% of primary production, high abundance of mixotrophic phytoplankton, low mesozooplankton grazing (∼6% of primary production and low export (∼7% of primary production. Zooplankton grazing and export of detritus were sensitive to CO2: grazing decreased and export increased with increasing pCO2. Nutrient addition halfway through the experiment increased the export, but not the production rates. Although mixotrophs showed initially higher production rates with increasing CO2, the overall production of POC (particulate organic carbon after nutrient addition decreased with increasing CO2. Interestingly, and contrary to the low nutrient situation, much more material settled down in the sediment traps at low CO2. The observed CO2 related effects potentially alter future organic carbon flows and export, with possible consequences for the efficiency of the biological pump.

  20. Plankton community structure and role of Oithona similis on the western coast of Greenland during the winter-spring transition

    DEFF Research Database (Denmark)

    Zamora-Terol, Sara; Nielsen, Torkel Gissel; Saiz, Enric

    2013-01-01

    The cyclopoid copepod Oithona similis is one of the most abundant copepods in the oceans, and has a potentially important role in pelagic food webs. However, there is a lack of knowledge on aspects of Oithona's biology and function in plankton communities. In the present study, we aimed to assess...... and compare its trophic role in Greenlandic coastal waters during the winter-spring transition, with a focus on its winter behaviour, when large calanoids are not present in the surface layer. Two locations were studied: waters offshore from Godthåbsfjord (Nuuk) in winter, and Qeqertarsuaq (Disko Bay...

  1. Qualitative importance of the microbial loop and plankton community structure in a eutropic lake during a bloom of Cyanobacteria

    DEFF Research Database (Denmark)

    Christoffersen, K.

    1990-01-01

    Plankton community structure and m~or pools and fluxes of carbon were observed before and after culmination of a bloom of cyanobacteria in eutrophic Frederiksborg Slotsso, Denmark. Biomass changes of heterotrophic nanoflagellates, ciliates, microzooplankton (50 to 140 urn), and macrozooplankton...... smaller than 20 um replaced Aphanizornenon after the culmination of cyanobacteria. Bacterial net production peaked shortly after the culmination of the bloom (510 ug C liter- 1 d-') and decreased thereafter to a level of approximately 124 gg C liter-' d -~. Phytoplankton extracellular release of organic...

  2. Effects of wastewater treatment plant effluent inputs on planktonic metabolic rates and microbial community composition in the Baltic Sea

    DEFF Research Database (Denmark)

    Vaquer-Sunyer, Raquel; Reader, Heather E.; Muthusamy, Saraladevi

    2016-01-01

    ) contribute to eutrophication as they are important sources of nitrogen to coastal areas. Here, we evaluated the effects of wastewater treatment plant effluent inputs on Baltic Sea planktonic communities in four experiments. We tested for effects of effluent inputs on chlorophyll a content, bacterial....... An increase in BP and decrease in CR could be caused by high lability of the DOM that can support secondary bacterial production, without an increase in respiration. Increases in bacterial production and simultaneous decreases of primary production lead to more carbon being consumed in the microbial loop...

  3. Variability of the planktonic foraminifera community across the Eocene/Oligocene boundary, Fuente Caldera Section, Baetic Ranges (Spain)

    Science.gov (United States)

    Legarda-Lisarri, A.

    2013-12-01

    During the Eocene/Oligocene transition, in a massive extinction event that took place about 33.7 million years ago, the current high resolution study analyzes qualitatively and quantitatively the community structure of the planktonic foraminifera that were preserved in the hemipelagic sediments of the Tethys Sea. The sampled section of the Fuente Caldera column, located in the Baetic mountain ranges, spans a register of 396,551.7 years. Based in the identification of 27 species, that belong to 13 genera and 2 families of foraminifera, there have been found three biozones of Gonzalvo Zonation (Gonzalvo, 2002) in the studied stratigraphic interval: Turborotalia cocoaensis and Cribrohantkenina lazzarii Biozones (Rupelian), and Paragloborotalia increbescens (Priabonian). The planktonic foraminifera associations variability patterns are defined by paleoecologic indexes (diversity index, high and low latitude species index and planktonic and benthic foraminifera index), by geochemical proxies: δ18O and δ13C and by 'Q' Mode Factor Analysis. They prove that the deposition environment is outer platform and also, they suggest that the studied area in the Tethys Sea underwent many thermal pulses, during which some species extinct or appear. In the first extinction event the species Turborotalia cocoaensis and Turborotalia cunialensis became extinct. In the second one, Hantkenina alabamensis, Hantkenina brevispina, Cribrohantkenina lazzarii and Pseudohastigerina micra became extinct while a succession occured; Globigerina officinalis, Globoturborotalita anguliofficinalis and Tenuitellinata angustiumbilicata appeared. The cooling event that finished in the Lower Oligocene was the biggest of these pulses, which was extremely abrupt and corresponds to the Oi-1 event that was described by Miller (Miller, 1991). All this evidences that the planktonic foraminifera extinction in the Upper Eocene was a gradual and fast event, what is supported by the Factor Analysis application. Key

  4. Comparative study of potential transfer of natural and anthropogenic cadmium to plankton communities in the North-West African upwelling

    International Nuclear Information System (INIS)

    Auger, P.A.; Machu, E.; Gorgues, T.; Grima, N.; Waeles, M.

    2015-01-01

    A Lagrangian approach based on a physical–biogeochemical modeling was used to compare the potential transfer of cadmium (Cd) from natural and anthropogenic sources to plankton communities (Cd-uptake) in the North-West African upwelling. In this region, coastal upwelling was estimated to be the main natural source of Cd while the most significant anthropogenic source for marine ecosystem is provided by phosphate industry. In our model experiment, Cd-uptake (natural or anthropogenic) in the North-West African upwelling is the result of an interplay between the Cd dispersion (by advection processes) and the simulated biological productivity. In the Moroccan waters, advection processes limit the residence time of water masses resulting in a low natural Cd-uptake by plankton communities while anthropogenic Cd-uptake is high. As expected, the situation is reversed in the Senegalo-Mauritanian upwelling where natural Cd-uptake is higher than anthropogenic Cd-uptake. Based upon an estimate of Cd sources, our modeling study shows, unexpectedly, that the anthropogenic signal of potential Cd-bioaccumulation in the Moroccan upwelling is of the same order of magnitude as the natural signal mainly present in the Senegalo-Mauritanian upwelling region. A comparison with observed Cd levels in mollusk and fishes, which shows overall agreement with our simulations, is confirming our estimates. - Highlights: • We model the physical–biogeochemical dynamics in the North-West African upwelling. • We model the transport of cadmium from natural and anthropogenic sources. • We derive proxies of potential cadmium absorption and bioaccumulation in the plankton food chain. • The anthropogenic signal off Morocco at least equals the natural upwelling signal off Mauritania. • We compare our results with observed cadmium levels in mollusks and fishes

  5. Comparative study of potential transfer of natural and anthropogenic cadmium to plankton communities in the North-West African upwelling

    Energy Technology Data Exchange (ETDEWEB)

    Auger, P.A., E-mail: pierreamael.auger@gmail.com [Laboratoire de Physique des Océans (LPO), UMR-CNRS 6523/IFREMER/IRD/UBO, BP70, 29280 Plouzané (France); Machu, E.; Gorgues, T.; Grima, N. [Laboratoire de Physique des Océans (LPO), UMR-CNRS 6523/IFREMER/IRD/UBO, BP70, 29280 Plouzané (France); Waeles, M. [Université de Bretagne Occidentale (UBO), Laboratoire de l' Environnement Marin (LEMAR), UMR-CNRS 6539/IRD/UBO, place N. Copernic, 29280 Plouzané (France)

    2015-02-01

    A Lagrangian approach based on a physical–biogeochemical modeling was used to compare the potential transfer of cadmium (Cd) from natural and anthropogenic sources to plankton communities (Cd-uptake) in the North-West African upwelling. In this region, coastal upwelling was estimated to be the main natural source of Cd while the most significant anthropogenic source for marine ecosystem is provided by phosphate industry. In our model experiment, Cd-uptake (natural or anthropogenic) in the North-West African upwelling is the result of an interplay between the Cd dispersion (by advection processes) and the simulated biological productivity. In the Moroccan waters, advection processes limit the residence time of water masses resulting in a low natural Cd-uptake by plankton communities while anthropogenic Cd-uptake is high. As expected, the situation is reversed in the Senegalo-Mauritanian upwelling where natural Cd-uptake is higher than anthropogenic Cd-uptake. Based upon an estimate of Cd sources, our modeling study shows, unexpectedly, that the anthropogenic signal of potential Cd-bioaccumulation in the Moroccan upwelling is of the same order of magnitude as the natural signal mainly present in the Senegalo-Mauritanian upwelling region. A comparison with observed Cd levels in mollusk and fishes, which shows overall agreement with our simulations, is confirming our estimates. - Highlights: • We model the physical–biogeochemical dynamics in the North-West African upwelling. • We model the transport of cadmium from natural and anthropogenic sources. • We derive proxies of potential cadmium absorption and bioaccumulation in the plankton food chain. • The anthropogenic signal off Morocco at least equals the natural upwelling signal off Mauritania. • We compare our results with observed cadmium levels in mollusks and fishes.

  6. Interspecies Interactions Reverse the Hazard of Antibiotics Exposure: A Plankton Community Study on Responses to Ciprofloxacin hydrochloride.

    Science.gov (United States)

    Wang, Changyou; Wang, Ziyang; Zhang, Yong; Su, Rongguo

    2017-05-24

    The ecotoxicological effects of Ciprofloxacin hydrochloride (CIP) were tested on population densities of plankton assemblages consisting of two algae (Isochrysis galbana and Platymonas subcordiformis) and a rotifer (Brachionus plicatilis). The I. galbana showed a significant decrease in densities when concentrations of CIP were above 2.0 mg L -1 in single-species tests, while P. subcordiformis and B. plicatilis were stable in densities when CIP were less than10.0 mg L -1 . The equilibrium densities of I. galbana in community test increased with CIP concentrations after falling to a trough at 5.0 mg L -1 , showed a completely different pattern of P. subcordiformis which decreased with CIP concentrations after reaching a peak at 30.0 mg L -1 . The observed beneficial effect was a result of interspecies interactions of trophic cascade that buffered for more severe direct effects of toxicants. The community test-based NOEC of CIP (2.0 mg L -1 ), embodying the indirect effects, was different from the extrapolated one derived by single-species tests (0.5 mg L -1 ), but all lacked confidence interval. A CIP threshold concentration of obvious relevance to ecological interaction was calculated with a simplified plankton ecological model, achieving a value of 1.26 mg L -1 with a 95% bootstrapping confidence interval from 1.18 to 1.31 mg L -1 .

  7. The planktonic communities of the Jamaican south-east coast; a comparison of harbor, shelf and oceanic areas

    Directory of Open Access Journals (Sweden)

    Hugh Small

    2014-09-01

    Full Text Available Few studies have compared water quality and plankton along the eutrophication gradient from Kingston Harbour to oceanic waters around Jamaica. To compare the planktonic community along the expected nutrient gradient, we sampled every two weeks at four stations, from eutrophic Kingston Harbour to oceanic California Bank. Phytoplankton was assessed from whole water Niskin bottle casts and zooplankton by vertical hauls with plankton nets of three different mesh sizes: 64µm, 200µm, and 600µm. Total phytoplankton biomass declined sharply away from the harbour (1.0 μg L-1 at the Harbour Shoal Beacon to 0.2 μg L-1 at California Bank. Characteristic estuarine phytoplankton genera -such as Ceratium, Gonyaulax, Gyrodinium and Rhizosolenia- dominated harbour samples while genera characteristic of offshore locations -such as Asterionelliopsis, Navicula, Nitzschia, Rhizosolenia and Thalassionema- dominated California Bank. Highest phytoplankton densities (mean values of 34 174 cells L-1 were found at the harbor mouth. Mean zooplankton abundances ranged from maximum (5 858.5m-3 at Beacon to minimum (2 124.2 m-3 at California; 171 species of zooplankton were identified and copepods dominated with 76 species. Overall, 75 species of zooplankton were identified from Beacon, 107 from Port Royal Cays- South East Cay, 110 from the exposed shelf edge- Windward Edge, and 95 from the oceanic California Bank. Larval forms dominated; copepod nauplii, fish eggs and echinoderm larvae occurred at all sites. Lucifer faxoni and Penilia avirostris were indicative of harbor waters and Microsetella sp. and Farranula carinata of offshore waters. Some zooplankton taxa, like L. faxoni, Paracalanus parvus and copepod nauplii, despite showing gradual decline with distance from Beacon to the Edge, increased in abundance at the furthest station, California. California Bank clearly experiences enrichment which at times can be as high as near-shore areas, but the planktonic

  8. Glacial meltwater influences on plankton community structure and the importance of top-down control (of primary production) in a NE Greenland fjord

    DEFF Research Database (Denmark)

    Arendt, Kristine Engel; Agersted, Mette Dalgaard; Sejr, Mikael Kristian

    2016-01-01

    Freshwater runoff from the Greenland Ice Sheet (GIS) can be an important driver influencing plankton community structure in Greenland fjords. In the present study, we describe physical, taxonomic and functional differences in the plankton community in Young Sound, a NE Greenland fjord, from......, and their grazing impact was the highest among the copepod groups. Copepod grazing impact on the phytoplankton standing stock, however, was exceeded by microzooplankton grazing, investigated by dilution experiments, with the highest grazing impact on the phytoplankton standing stock of 63% d−1 in the inner part...

  9. Environmental modulation of the plankton community composition and size-structure along the eutrophic intertidal coast of the Río de la Plata estuary, Argentina

    Directory of Open Access Journals (Sweden)

    Maximiliano D. Garcia

    2014-05-01

    Full Text Available In this study we investigated the spatial distribution of the plankton community, bacterio-, phyto- and zooplankton, in relation with environmental conditions along the intertidal coast of the Río de la Plata estuary, Argentina. Plankton was analyzed in terms of species composition, abundance, biomass (carbon content and size-structure. We aim to evaluate the potential effects of anthropogenic impacts (e.g., nutrient enrichment and physicochemical gradients alongshore (e.g., salinity, turbidity on the composition and functioning of the plankton. We asked whether the natural structuring of the plankton by salinity and turbidity, known to be true of estuaries, is modified by eutrophication along the studied shoreline. We found that the density and biomass of bacteria and phytoplankton were strikingly enhanced by high eutrophication levels along the intertidal southwest coast of the Río de la Plata estuary. We also found that the highest zooplankton density in the most polluted area but the biomass showed a different distribution pattern. Nevertheless, when zooplankton was analyzed by means of its size fraction, we accordingly found that the microzooplankton biomass was positively associated with smaller-size phytoplankton groups and the most polluted study sites. Copepods were the major taxonomic groups that best represented the mesozooplankton biomass. We therefore expected that its distribution was modulated by the presence of its food items (i.e., large cells which, in turn, were more abundant in the middle-outer zone. In contrast, we found that the highest biomass of copepods occurred at the innermost site of the estuary and we found no significant association with other planktonic groups. Overall, this study highlights the noteworthy impacts of human activities modifying the functioning of this coastal ecosystem. The differences found in the taxonomic composition and size structure of the planktonic community assemblage between the most

  10. Plankton community and the relationship with the environment in saline lakes of Onon-Torey plain, Northeastern Mongolia.

    Science.gov (United States)

    Afonina, Ekaterina Yu; Tashlykova, Natalya A

    2018-02-01

    The plankton community of sixteen saline lakes located on Onon-Torey plain (Northeastern Mongolia) during the filling phase and the raising of the water level was investigated in July 2011. Thirty-five taxa of phytoplankton and thirty-one species of zooplankton were found. For phytoplankton, blue-green algae ( Merismopedia elegans , Anabaenopsis elenkinii , Arthrospora fusiformis , Spirulina major , Lyngbya sp., Oscillatoria sp.) and green algae ( Monoraphidium minutum , Tetrastrum komarekii , Ankyra ocellata , Oocystis sp.) were dominant. For zooplankton, Filinia longiseta, Brachionus plicatilis , B. variabilis , Hexarthra mira (Rotifera), Daphnia magna , Moina brachiata , M. mongolica (Cladocera), Arctodiaptomus bacillifer , Mixodiaptomus incrassatus , Metadiaptomus asiaticus (Copepoda) dominated. Mineralization, active hydrogen ratio, dissolved oxygen and water temperature were the main factors influencing the diversity, structure and distribution of plankton organisms in the steppe lakes during low water level. The RDA analysis for phytoplankton and zooplankton from different lakes was carried out for selected two groups which included lakes and a subset related species. The first group is of oligohaline and mesohaline lakes in which mostly green algae, rotifers and copepods inhabit. The second group is of mesohaline and polyhaline lakes with mainly blue-green algae , some crustaceans and rotifers inhabiting. High abundance and biomass of Spirulina major , Oscillatoria sp. and Brachionus variabilis were observed in lakes with high mineralization, pH and temperature.

  11. Plankton community and the relationship with the environment in saline lakes of Onon-Torey plain, Northeastern Mongolia

    Directory of Open Access Journals (Sweden)

    Ekaterina Yu. Afonina

    2018-02-01

    Full Text Available The plankton community of sixteen saline lakes located on Onon-Torey plain (Northeastern Mongolia during the filling phase and the raising of the water level was investigated in July 2011. Thirty-five taxa of phytoplankton and thirty-one species of zooplankton were found. For phytoplankton, blue-green algae (Merismopedia elegans, Anabaenopsis elenkinii, Arthrospora fusiformis, Spirulina major, Lyngbya sp., Oscillatoria sp. and green algae (Monoraphidium minutum, Tetrastrum komarekii, Ankyra ocellata, Oocystis sp. were dominant. For zooplankton, Filinia longiseta, Brachionus plicatilis, B. variabilis, Hexarthra mira (Rotifera, Daphnia magna, Moina brachiata, M. mongolica (Cladocera, Arctodiaptomus bacillifer, Mixodiaptomus incrassatus, Metadiaptomus asiaticus (Copepoda dominated. Mineralization, active hydrogen ratio, dissolved oxygen and water temperature were the main factors influencing the diversity, structure and distribution of plankton organisms in the steppe lakes during low water level. The RDA analysis for phytoplankton and zooplankton from different lakes was carried out for selected two groups which included lakes and a subset related species. The first group is of oligohaline and mesohaline lakes in which mostly green algae, rotifers and copepods inhabit. The second group is of mesohaline and polyhaline lakes with mainly blue-green algae, some crustaceans and rotifers inhabiting. High abundance and biomass of Spirulina major, Oscillatoria sp. and Brachionus variabilis were observed in lakes with high mineralization, pH and temperature.

  12. The annual planktonic protist community structure in an ice-free high Arctic fjord (Adventfjorden, West Spitsbergen)

    Science.gov (United States)

    Kubiszyn, A. M.; Wiktor, J. M.; Wiktor, J. M.; Griffiths, C.; Kristiansen, S.; Gabrielsen, T. M.

    2017-05-01

    We investigated the size and trophic structure of the annual planktonic protist community structure in the ice-free Adventfjorden in relation to environmental factors. Our high-resolution (weekly to monthly) study was conducted in 2012, when warm Atlantic water was advected into the fjord in winter and summer. We observed a distinct seasonality in the protist communities. The winter protist community was characterised by extremely low levels of protist abundance and biomass (primarily Dinophyceae, Ciliophora and Bacillariophyceae) in a homogenous water column. In the second half of April, the total protist abundance and biomass rapidly increased, thus initiating the spring bloom in a still well-mixed water column. The spring bloom was initially dominated by the prymnesiophyte Phaeocystis pouchetii and Bacillariophyceae (primarily from the genera Thalassiosira, Fragilariopsis and Chaetoceros) and was later strictly dominated by Phaeocystis colonies. When the bloom terminated in mid-June, the community shifted towards flagellates (Dinophyceae, Ciliophora, Cryptophyceae and nanoflagellates 3-7 μm in size) in a stratified, nutrient-depleted water column. Decreases in the light intensity decreased the protist abundance and biomass, and the fall community (Dinophyceae, Cryptophyceae and Bacillariophyceae) was followed by the winter community.

  13. The community structure and seasonal dynamics of plankton in Bange Lake, northern Tibet, China

    Science.gov (United States)

    Zhao, Wen; Zhao, Yuanyi; Wang, Qiaohan; Zheng, Mianping; Wei, Jie; Wang, Shan

    2016-11-01

    The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in the saline Bange Lake, northern Tibet, China. Sampling was carried out between one to three times per month from May 2001 to July 2002. Salinity ranged from 14 to 146. The air and water temperature exhibited a clear seasonal pattern, and mean annual temperatures were approximately 4.8°C and 7.3°C, respectively. The lowest water temperature occurred in winter from December to March at -2°C and the highest in June and July at 17.7°C. Forty-one phytoplankton taxa, 21 zooplankton, and 5 benthic or facultative zooplankton were identified. The predominant phytoplankton species were Gloeothece linearis, Oscillatoria tenuis, Gloeocapsa punctata, Ctenocladus circinnatus, Dunaliella salina, and Spirulina major. The predominant zooplankton species included Holophrya actra, Brachionus plicatilis, Daphniopsis tibetana, Cletocamptus dertersi, and Arctodiaptomus salinus. The mean annual total phytoplankton density and biomass for the entire lake were 4.52×107 cells/L and 1.60 mg/L, respectively. The annual mean zooplankton abundance was 52, 162, 322, and 57, 144 ind./L, in the three sublakes. The annual mean total zooplankton biomass in Lakes 1-3 was 1.23, 9.98, and 2.13 mg/L, respectively. The annual mean tychoplankton abundances in Bg1, 2, and 3 were 47, 67, and 654 ind./L. The annual mean tychoplankton biomass was 2.36, 0.16, and 2.03 mg/L, respectively. The zooplankton biomass (including tychoplankton) in the lake was 9.11 mg/L. The total number of plankton species in the salt lake was significantly negatively correlated with salinity.

  14. Carbohydrate supply limits invasion of natural communities by Argentine ants.

    Science.gov (United States)

    Rowles, Alexei D; Silverman, Jules

    2009-08-01

    The ability of species to invade new habitats is often limited by various biotic and physical factors or interactions between the two. Invasive ants, frequently associated with human activities, flourish in disturbed urban and agricultural environments. However, their ability to invade and establish in natural habitats is more variable. This is particularly so for the invasive Argentine ant (Linepithema humile). While biotic resistance and low soil moisture limits their invasion of natural habitats in some instances, the effect of food availability has been poorly explored. We conducted field experiments to determine if resource availability limits the spread and persistence of Argentine ants in remnant natural forest in North Carolina. Replicated transects paired with and without sucrose solution feeding stations were run from invaded urban edges into forest remnants and compared over time using baits and direct counts at feeding stations. Repeated under different timing regimes in 2006 and 2007, access to sucrose increased local Argentine ant abundances (1.6-2.5 fold) and facilitated their progression into the forest up to 73 +/- 21% of 50-m transects. Resource removal caused an expected decrease in Argentine ant densities in 2006, in conjunction with their retreat to the urban/forest boundary. However, in 2007, Argentine ant numbers unexpectedly continued to increase in the absence of sugar stations, possibly through access to alternative resources or conditions not available the previous year such as honeydew-excreting Hemiptera. Our results showed that supplementing carbohydrate supply facilitates invasion of natural habitat by Argentine ants. This is particularly evident where Argentine ants continued to thrive following sugar station removal.

  15. Microbial planktonic communities in the Red Sea: high levels of spatial and temporal variability shaped by nutrient availability and turbulence

    KAUST Repository

    Pearman, John K.; Ellis, Joanne; Irigoien, Xabier; Yellepeddi, Sarma B.; Jones, Burton; Carvalho, Susana

    2017-01-01

    The semi-enclosed nature of the Red Sea (20.2°N-38.5°N) makes it a natural laboratory to study the influence of environmental gradients on microbial communities. This study investigates the composition and structure of microbial prokaryotes and eukaryotes using molecular methods, targeting ribosomal RNA genes across different regions and seasons. The interaction between spatial and temporal scales results in different scenarios of turbulence and nutrient conditions allowing for testing of ecological theory that categorizes the response of the plankton community to these variations. The prokaryotic reads are mainly comprised of Cyanobacteria and Proteobacteria (Alpha and Gamma), with eukaryotic reads dominated by Dinophyceae and Syndiniophyceae. Periodic increases in the proportion of Mamiellophyceae and Bacillariophyceae reads were associated with alterations in the physical oceanography leading to nutrient increases either through the influx of Gulf of Aden Intermediate Water (south in the fall) or through water column mixing processes (north in the spring). We observed that in general dissimilarity amongst microbial communities increased when nutrient concentrations were higher, whereas richness (observed OTUs) was higher in scenarios of higher turbulence. Maximum abundance models showed the differential responses of dominant taxa to temperature giving an indication how taxa will respond as waters become warmer and more oligotrophic.

  16. Microbial planktonic communities in the Red Sea: high levels of spatial and temporal variability shaped by nutrient availability and turbulence

    KAUST Repository

    Pearman, John K.

    2017-07-20

    The semi-enclosed nature of the Red Sea (20.2°N-38.5°N) makes it a natural laboratory to study the influence of environmental gradients on microbial communities. This study investigates the composition and structure of microbial prokaryotes and eukaryotes using molecular methods, targeting ribosomal RNA genes across different regions and seasons. The interaction between spatial and temporal scales results in different scenarios of turbulence and nutrient conditions allowing for testing of ecological theory that categorizes the response of the plankton community to these variations. The prokaryotic reads are mainly comprised of Cyanobacteria and Proteobacteria (Alpha and Gamma), with eukaryotic reads dominated by Dinophyceae and Syndiniophyceae. Periodic increases in the proportion of Mamiellophyceae and Bacillariophyceae reads were associated with alterations in the physical oceanography leading to nutrient increases either through the influx of Gulf of Aden Intermediate Water (south in the fall) or through water column mixing processes (north in the spring). We observed that in general dissimilarity amongst microbial communities increased when nutrient concentrations were higher, whereas richness (observed OTUs) was higher in scenarios of higher turbulence. Maximum abundance models showed the differential responses of dominant taxa to temperature giving an indication how taxa will respond as waters become warmer and more oligotrophic.

  17. Bacterioplankton: a sink for carbon in a coastal marine plankton community

    International Nuclear Information System (INIS)

    Ducklow, H.W.; Purdie, D.A.; Williams, P.J.LeB.; Davis, J.M.

    1986-01-01

    Recent determinations of high production rates (up to 30% of primary production in surface waters) implicate free-living marine bacterioplankton as a link in a microbial loop that supplements phytoplankton as food for herbivores. An enclosed water column of 300 cubic meters was used to test the microbial loop hypothesis by following the fate of carbon-14-labeled bacterioplankton for over 50 days. Only 2% of the label initially fixed from carbon-14-labeled glucose by bacteria was present in larger organisms after 13 days, at which time about 20% of the total label added remained in the particulate fraction. Most of the label appeared to pass directly from particles smaller than 1 micrometer (heterotrophic bacterioplankton and some bacteriovores) to respired labeled carbon dioxide or to regenerated dissolved organic carbon-14. Secondary (and, by implication, primary) production by organisms smaller than 1 micrometer may not be an important food source in marine food chains. Bacterioplankton can be a sink for carbon in planktonic food webs and may serve principally as agents of nutrient regeneration rather than as food

  18. Plankton communities and summertime declines in algal abundance associated with low dissolved oxygen in the Tualatin River, Oregon

    Science.gov (United States)

    Carpenter, Kurt D.; Rounds, Stewart A.

    2013-01-01

    and water-quality sample data from 2006 to 2008 were combined with parts of a larger discrete-sample and continuous water-quality monitoring dataset and examined to identify patterns in water-quality and algal conditions since 1991, with a particular emphasis on 2003–08. Longitudinal plankton surveys were conducted in 2006–08 at six sites between river miles (RM) 24.5 and 3.4 at 2- to 3-week intervals, or 5–6 per season, and in-situ bioassay experiments were conducted in 2008 to examine the potential effects of wastewater treatment facility (WWTF) effluent and phosphorus additions on phytoplankton biomass and algal photosynthesis. Phytoplankton and zooplankton community composition, streamflow, and water-quality data were analyzed using multivariate statistical techniques to gain insights into plankton dynamics to determine what factors might be most tied to the abundance and characteristics of the phytoplankton assemblages, and identify possible causes of their declines. The connection between low-DO events and algal declines was clearly evident, as bloom crashes were nearly always followed by periods of low DO. Algal blooms occurred each year during 2006–08, producing maximum chlorophyll-a (Chl-a) values in June or July generally in the range of 50–80 micrograms per liter (µg/L). Bloom crashes and absence of sufficient algal photosynthesis in mid- to late-summer contributed to minimum DO concentrations that were less than the State standard of 6.5 milligrams per liter (mg/L) based on the 30-day mean daily concentration, for 62–74 days each year. At times, the absolute minimum State standard (4 mg/L DO) also was not met. To learn more about why low-DO events occurred, specific algal declines during 2003–08 were scrutinized to determine their likely causal factors. From this information, a series of hypotheses were formulated and evaluated in terms of their ability to explain recent declines in algal populations in the river in late summer

  19. Structural and functional insights from the metagenome of an acidic hot spring microbial planktonic community in the Colombian Andes.

    Directory of Open Access Journals (Sweden)

    Diego Javier Jiménez

    Full Text Available A taxonomic and annotated functional description of microbial life was deduced from 53 Mb of metagenomic sequence retrieved from a planktonic fraction of the Neotropical high Andean (3,973 meters above sea level acidic hot spring El Coquito (EC. A classification of unassembled metagenomic reads using different databases showed a high proportion of Gammaproteobacteria and Alphaproteobacteria (in total read affiliation, and through taxonomic affiliation of 16S rRNA gene fragments we observed the presence of Proteobacteria, micro-algae chloroplast and Firmicutes. Reads mapped against the genomes Acidiphilium cryptum JF-5, Legionella pneumophila str. Corby and Acidithiobacillus caldus revealed the presence of transposase-like sequences, potentially involved in horizontal gene transfer. Functional annotation and hierarchical comparison with different datasets obtained by pyrosequencing in different ecosystems showed that the microbial community also contained extensive DNA repair systems, possibly to cope with ultraviolet radiation at such high altitudes. Analysis of genes involved in the nitrogen cycle indicated the presence of dissimilatory nitrate reduction to N2 (narGHI, nirS, norBCDQ and nosZ, associated with Proteobacteria-like sequences. Genes involved in the sulfur cycle (cysDN, cysNC and aprA indicated adenylsulfate and sulfite production that were affiliated to several bacterial species. In summary, metagenomic sequence data provided insight regarding the structure and possible functions of this hot spring microbial community, describing some groups potentially involved in the nitrogen and sulfur cycling in this environment.

  20. Structural and Functional Insights from the Metagenome of an Acidic Hot Spring Microbial Planktonic Community in the Colombian Andes

    Science.gov (United States)

    Jiménez, Diego Javier; Andreote, Fernando Dini; Chaves, Diego; Montaña, José Salvador; Osorio-Forero, Cesar; Junca, Howard; Zambrano, María Mercedes; Baena, Sandra

    2012-01-01

    A taxonomic and annotated functional description of microbial life was deduced from 53 Mb of metagenomic sequence retrieved from a planktonic fraction of the Neotropical high Andean (3,973 meters above sea level) acidic hot spring El Coquito (EC). A classification of unassembled metagenomic reads using different databases showed a high proportion of Gammaproteobacteria and Alphaproteobacteria (in total read affiliation), and through taxonomic affiliation of 16S rRNA gene fragments we observed the presence of Proteobacteria, micro-algae chloroplast and Firmicutes. Reads mapped against the genomes Acidiphilium cryptum JF-5, Legionella pneumophila str. Corby and Acidithiobacillus caldus revealed the presence of transposase-like sequences, potentially involved in horizontal gene transfer. Functional annotation and hierarchical comparison with different datasets obtained by pyrosequencing in different ecosystems showed that the microbial community also contained extensive DNA repair systems, possibly to cope with ultraviolet radiation at such high altitudes. Analysis of genes involved in the nitrogen cycle indicated the presence of dissimilatory nitrate reduction to N2 (narGHI, nirS, norBCDQ and nosZ), associated with Proteobacteria-like sequences. Genes involved in the sulfur cycle (cysDN, cysNC and aprA) indicated adenylsulfate and sulfite production that were affiliated to several bacterial species. In summary, metagenomic sequence data provided insight regarding the structure and possible functions of this hot spring microbial community, describing some groups potentially involved in the nitrogen and sulfur cycling in this environment. PMID:23251687

  1. Taxonomic and functional diversity of a coastal planktonic bacterial community in a river-influenced marine area.

    Science.gov (United States)

    Thiele, Stefan; Richter, Michael; Balestra, Cecilia; Glöckner, Frank Oliver; Casotti, Raffaella

    2017-04-01

    The Gulf of Naples is a dynamical area with intense exchanges between offshore oligotrophic and coastal eutrophic waters with frequent freshwater inputs. The Sarno River, one of the most polluted rivers in Europe, strongly contributes to the pollution of the area, discharging high amounts of heavy metals and organic wastes from heavily cultivated and industrial areas. This paper reports on the diversity and community structure of the marine residential Bacteria and Archaea of the Gulf of Naples in an area close to the river Sarno plume and investigates their small-scale taxonomic diversity and expression patterns as a proxy of potential metabolic activity using metagenomics and metatranscriptomics. Bacteria and Archaea were mainly represented by marine clades, with only minor contributors from freshwater ones. The community was dominated by Alpha- and Gammaproteobacteria, of which Rhodospirillales, Pelagibacteriales, and Oceanospirilalles were most represented. However, Alteromonadales and Rhodobacterales were the most active, despite their relative lower abundance, suggesting that they are important for overall ecosystem functioning and nutrient cycling. Nitrification and a reversed form of dissimilatory sulfate reduction were the major metabolic processes found in the metatrascriptomes and were mainly associated to Nitrosopumilales and Pelagibacter, respectively. No clear indication of transcripts related to stress induced by heavy metals or organic pollutants was found. In general, despite the high loads of pollutants discharged continuously by the Sarno River, the microbial community did not show marks of stress-induced changes neither structural nor functional, thus suggesting that this river has little or no effect on the planktonic bacterial community of the Gulf of Naples. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. The plankton community on Sukkertop and Fylla Banks off West Greenland during a spring bloom and post-bloom period: Hydrography, phytoplankton and protozooplankton

    DEFF Research Database (Denmark)

    Poulsen, Louise K.; Reuss, N.

    2002-01-01

    The plankton community structure was investigated on Sukkertop and Fylla Banks off West Greenland during the spring bloom in May 2000 and the post-bloom period in June 1999. In May a small change in density, clearly illustrated by the profile of potential energy, was sufficient to support a spring...... the phytoplankton community. Heterotrophic biomass was low (5 +/- 1 mg C m(-3)) and an important part was comprised by heterotrophic nanoflagellates (24 +/- 1%). Protozooplankters (heterotrophic dinoflagellates and ciliates) were important grazers of the phytoplankton community in the post-bloom period (estimated...

  3. Impact of single and repeated applications of the insecticide chlorpyrifos on tropical freshwater plankton communities

    NARCIS (Netherlands)

    Daam, M.A.; Brink, van den P.J.; Nogueira, A.J.A.

    2008-01-01

    This paper describes the effects of a single and a repeated application of the organophosphorus insecticide chlorpyrifos on zooplankton and phytoplankton communities in outdoor microcosms in Thailand. Treatment levels of 1 mu g L-1 were applied once or twice with a 2-week interval. Both treatments

  4. Crustacean plankton communities in forty-five lakes in the experimental lakes area, northwestern Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Patalas, K

    1971-01-01

    Zooplankton communities were characterized on the basis of samples taken in summer as vertical net hauls in the central part of lakes. Twenty-eight species of crustaceans were found in the 45 lakes studied. The highest number of species as well as the highest numbers of individuals (per unit of area) usually occurred in the largest deepest lakes with most transparent water.

  5. Fatty-acid ecology of plankton communities. Progress report, May 1, 1979-February 28, 1982

    Energy Technology Data Exchange (ETDEWEB)

    Jeffries, H. P.

    1981-12-01

    Distributions of organic constituents in marine communities should yield a worldwide classification scheme within which any localized phenomena would be immediately apparent. This idea was tested on the zooplankton along an environmental gradient extending from Rhode Island Sound, through Narragansett Bay and into its polluted tributary, the Providence River. On the basis of fatty acid composition, both the macro- and microzooplankton could be precisely classified to the habitat of origin. Biochemically the microzooplankton changed uniformly with respect to linear distance though the riverine, estuarine and offshore habitats. In macrozooplankton, the relation between biochemical change and linear distance from the river seaward was a power curve: sharply changing at first, becoming more nearly constant offshore. Particulate pollution in the river merely reinforced natural fatty acid sources in the zooplankton's food - part of a pattern in which environmentally induced effects were expressed inshore, genetic influences offshore. In each habitat species diversity was inversely related to the community's stability of fatty acid composition. These estimates revealed greatest dynamical robustness in the prolific yet simple riverine zooplankton, suggesting that the stable domain of parameter space was likewise greater here than offshore. Despite its diversity, microzooplankton was more dynamically fragile than the macrozooplankton, in agreement with current theory on the stability of communities. We conclude that monomeric composition offers a basic rationale for characterizing the sensitivities of natural communities to environmental change.

  6. Evaluation of parameters of a plankton community's biological rhythms under the natural environment of the Black Sea using the Fourier transform method.

    Science.gov (United States)

    Mel'nikova, Ye B

    2017-05-01

    Night-time changes in bioluminescence intensity in the coastal area of the Black Sea were recorded. It was noted that the biomass of luminous organisms is closely correlated with the biomass of plankton and other pelagic organisms, including commercial pelagic fish. The parameters of plankton communities' basic biological rhythms were determined using the discrete Fourier transform method. These rhythms were manifest as spatial and temporal changes in the bioluminescence intensity. It was shown that changes in the bioluminescence intensity over a 14.0-h period were due to the duration of the light/dark cycles. By contrast, changes in bioluminescence intensity with periods of 4.7 and 2.8 h were due to the endogenous rhythms of the plankton community (feeding and cell division). An original method for evaluating of errors in the calculated periods of the biological rhythms was proposed. A strong correlation (r = 0.906) was observed between the measured and calculated values for the bioluminescence intensity, which provided support for the assumptions made. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Ecological Stoichiometry of Ocean Plankton

    Science.gov (United States)

    Moreno, Allison R.; Martiny, Adam C.

    2018-01-01

    Marine plankton elemental stoichiometric ratios can deviate from the Redfield ratio (106C:16N:1P); here, we examine physiological and biogeochemical mechanisms that lead to the observed variation across lineages, regions, and seasons. Many models of ecological stoichiometry blend together acclimative and adaptive responses to environmental conditions. These two pathways can have unique molecular mechanisms and stoichiometric outcomes, and we attempt to disentangle the two processes. We find that interactions between environmental conditions and cellular growth are key to understanding stoichiometric regulation, but the growth rates of most marine plankton populations are poorly constrained. We propose that specific physiological mechanisms have a strong impact on plankton and community stoichiometry in nutrient-rich environments, whereas biogeochemical interactions are important for the stoichiometry of the oligotrophic gyres. Finally, we outline key areas with missing information that is needed to advance understanding of the present and future ecological stoichiometry of ocean plankton.

  8. Segregated Planktonic and Bottom-Dwelling Archaeal Communities in High-Temperature Acidic/Sulfuric Ponds of the Tatun Volcano Group, Northern Taiwan

    Directory of Open Access Journals (Sweden)

    Ting-Wen Cheng

    2013-01-01

    Full Text Available Geothermal environments are characterized by dynamic redox and temperature fluctuations inherited from the exposure of deeply-sourced, hot, reducing fluids to low-temperature, oxidizing ambient environments. To investigate whether microbial assemblages shifted in response to the changes of a redox state within acidic hot ponds, we collected three paired water and sediment samples from the Tatun Volcano Group, assessed metabolic roles of community members, and correlated their functional capabilities with geochemical factors along depth. Molecular analyses revealed that Sulfolobus spp., Acidianus spp. and Vulcanisaeta spp. capable of respiring elemental sulfur under oxic and/or low-oxygen conditions were the major archaeal members in planktonic communities. In contrast, obligate anaerobic Caldisphaera spp. dominated over others in bottom-dwelling communities. Bacteria were only detected in one locality wherein the majority was affiliated with microaerophilic Hydrogenobaculum spp. Cluster analyses indicated that archaeal communities associated with sediments tended to cluster together and branch off those with water. In addition, the quantities of dissolved oxygen within the water column were substantially less than those in equilibrium with atmospheric oxygen, indicating a net oxygen consumption most likely catalyzed by microbial processes. These lines of evidence suggest that the segregation of planktonic from bottom-dwelling archaeal assemblages could be accounted for by the oxygen affinities inherited in individual archaeal members. Community assemblages in geothermal ecosystems would be often underrepresented without cautious sampling of both water and sediments.

  9. The Continuous Plankton Imaging and Classification Sensor (CPICS): A Sensor for Quantifying Mesoplankton Biodiversity and Community Structure

    Science.gov (United States)

    Gallager, S. M.

    2016-02-01

    Marine ecosystems are changing at a variety of time scales as a function of a diverse suite of forcing functions both natural and anthropogenic. Establishing a continuous plankton time series consisting of scales from rapid (seconds) to long-term (decades), provides a sentinel for ecosystem change. The key is to measure plankton biodiversity at sufficiently fast time scales that allow disentanglement of physical (transport) and biological (growth) properties of an ecosystem. CPICS is a plankton and particle imaging microscope system that is designed to produce crisp darkfield images of light scattering material in aquatic environments. The open flow design is non-invasive and non-restrictive providing images of very fragile plankton in their natural orientation. Several magnifications are possible from 0.5 to 5x forming a field of view of 10cm to 1mm, respectively. CPICS has been installed on several cabled observing systems called OceanCubes off the coast of Okinawa and Tokyo, Japan providing a continuous stream of plankton images to a machine vision image classifier located at WHOI. Image features include custom algorithms for texture, color pattern, morphology and shape, which are extracted from in-focus target. The features are then used to train a classifier (e.g., Random Forest) resulting in classifications that are tested using cross-validation, confusion matrices and ROC curves. High (>90%) classification accuracies are possible depending on the number of training categories and target complexity. A web-based utility allows access to raw images, training sets, classifiers and classification results. Combined with chemical and physical data from the observatories, an ecologically meaningful plankton index of biodiversity and its variance is developed using a combination of species and taxon groups, which provides an approach for understanding ecosystem change without the need to identify all targets to species. http://oceancubes.whoi.edu/instruments/CPICS

  10. Influence of ocean acidification on plankton community structure during a winter-to-summer succession: An imaging approach indicates that copepods can benefit from elevated CO2 via indirect food web effects

    Science.gov (United States)

    Taucher, Jan; Haunost, Mathias; Boxhammer, Tim; Bach, Lennart T.; Algueró-Muñiz, María; Riebesell, Ulf

    2017-01-01

    Plankton communities play a key role in the marine food web and are expected to be highly sensitive to ongoing environmental change. Oceanic uptake of anthropogenic carbon dioxide (CO2) causes pronounced shifts in marine carbonate chemistry and a decrease in seawater pH. These changes–summarized by the term ocean acidification (OA)–can significantly affect the physiology of planktonic organisms. However, studies on the response of entire plankton communities to OA, which also include indirect effects via food-web interactions, are still relatively rare. Thus, it is presently unclear how OA could affect the functioning of entire ecosystems and biogeochemical element cycles. In this study, we report from a long-term in situ mesocosm experiment, where we investigated the response of natural plankton communities in temperate waters (Gullmarfjord, Sweden) to elevated CO2 concentrations and OA as expected for the end of the century (~760 μatm pCO2). Based on a plankton-imaging approach, we examined size structure, community composition and food web characteristics of the whole plankton assemblage, ranging from picoplankton to mesozooplankton, during an entire winter-to-summer succession. The plankton imaging system revealed pronounced temporal changes in the size structure of the copepod community over the course of the plankton bloom. The observed shift towards smaller individuals resulted in an overall decrease of copepod biomass by 25%, despite increasing numerical abundances. Furthermore, we observed distinct effects of elevated CO2 on biomass and size structure of the entire plankton community. Notably, the biomass of copepods, dominated by Pseudocalanus acuspes, displayed a tendency towards elevated biomass by up to 30–40% under simulated ocean acidification. This effect was significant for certain copepod size classes and was most likely driven by CO2-stimulated responses of primary producers and a complex interplay of trophic interactions that allowed this

  11. Short-term effects of medetomidine on photosynthesis and protein synthesis in periphyton, epipsammon and plankton communities in relation to predicted environmental concentrations.

    Science.gov (United States)

    Ohlauson, Cecilia; Eriksson, Karl Martin; Blanck, Hans

    2012-01-01

    Medetomidine is a new antifouling substance, highly effective against barnacles. As part of a thorough ecotoxicological evaluation of medetomidine, its short-term effects on algal and bacterial communities were investigated and environmental concentrations were predicted with the MAMPEC model. Photosynthesis and bacterial protein synthesis for three marine communities, viz. periphyton, epipsammon and plankton were used as effect indicators, and compared with the predicted environmental concentrations (PECs). The plankton community showed a significant decrease in photosynthetic activity of 16% at 2 mg l⁻¹ of medetomidine, which was the only significant effect observed. PECs were estimated for a harbor, shipping lane and marina environment using three different model scenarios (MAMPEC default, Baltic and OECD scenarios). The highest PEC of 57 ng l⁻¹, generated for a marina with the Baltic scenario, was at least 10,000-fold lower than the concentration that significantly decreased photosynthetic activity. It is concluded that medetomidine does not cause any acute toxic effects on bacterial protein synthesis and only small acute effects on photosynthesis at high concentrations in marine microbial communities. It is also concluded that the hazard from medetomidine on these processes is low since the effect levels are much lower than the highest PEC.

  12. Structural and Functional Insights from the Metagenome of an Acidic Hot Spring Microbial Planktonic Community in the Colombian Andes

    NARCIS (Netherlands)

    Jiménez Avella, Diego; Dini Andreote, Fernando; Chaves, Diego; Montaña, José Salvador; Osorio-Forero, Cesar; Junca, Howard; Zambrano, María Mercedes; Baena, Sandra

    2012-01-01

    A taxonomic and annotated functional description of microbial life was deduced from 53 Mb of metagenomic sequence retrieved from a planktonic fraction of the Neotropical high Andean (3,973 meters above sea level) acidic hot spring El Coquito (EC). A classification of unassembled metagenomic reads

  13. Composition of planktonic organisms and its associated physico ...

    African Journals Online (AJOL)

    Composition of plankton communities in two ponds at African Regional Agriculture Centre (ARAC) Aluu, Port Harcourt was undertaken between May and June 2004, to assess the composition, relative abundance and distribution of plankton. The diversity of plankton was poor. Twenty-eight taxa representing four (4) families ...

  14. Planktonic interactions and chaotic advection in Langmuir circulation

    DEFF Research Database (Denmark)

    Bees, Martin Alan; Mezic, I.; McGlade, J.

    1998-01-01

    The role of unsteady laminar flows for planktonic communities is investigated. Langmuir circulation is used, as a typical medium-scale structure, to illustrate mechanisms for the generation of plankton patches. Two behaviours are evident: chaotic regions that help to spread plankton and locally...

  15. Metabolic syndrome in breast cancer survivors with high carbohydrate consumption: The first report in community setting.

    Science.gov (United States)

    Park, Boyoung; Kong, Sun-Young; Lee, Eun Kyung; Lee, Moo Hyun; Lee, Eun Sook

    2017-10-01

    This study was conducted to examine the prevalence of and lifestyle factors associated with the metabolic syndrome in breast cancer survivors and to compare those factors with controls without cancer in a community setting. This study included 584 female breast cancer survivors ≥3 years after the initial diagnosis and 2336 age-matched cancer-free female controls from 39 community health examination centers located in 14 urban areas in Korea. The prevalence of the metabolic syndrome is shown. Factors associated with the metabolic syndrome were analyzed as odds ratios (ORs) in cancer survivors and controls; differences between the two groups in the ORs of associated factors were evaluated by calculating p-heterogeneity values. The prevalence of metabolic syndrome in breast cancer survivors and age-matched controls were 26.8% and 26.9%, respectively. Higher percentage of caloric intake from carbohydrates was associated with increased metabolic syndrome only in the breast cancer survivors (OR for the highest vs. lowest quartile for survivors = 2.48 [95% CI = 1.20-5.14]; OR for controls = 1.11 [95% CI = 0.81-1.51]; P-heterogeneity = 0.046). Sweat-inducing exercise for ≥150 min/week was associated with a lower risk of metabolic syndrome only in controls (controls: OR = 0.72 [95% CI = 0.58-0.89]; survivors: OR = 0.88 [95% CI = 0.57-1.36]). Older age, higher body mass index, and a lower education level (≤12 years) was associated with an increased prevalence of metabolic syndrome in both groups. Our results suggest that, in regions with excess carbohydrate intake, the association of the metabolic syndrome with percentage of caloric intake from carbohydrate might be more prominent than exercise in breast cancer survivors, compared with general population. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  16. Polyunsaturated fats, carbohydrates and carotid disease: The Atherosclerosis Risk in Communities (ARIC) Carotid MRI study.

    Science.gov (United States)

    Dearborn, Jennifer L; Qiao, Ye; Guallar, Eliseo; Steffen, Lyn M; Gottesman, Rebecca F; Zhang, Yiyi; Wasserman, Bruce A

    2016-08-01

    Carbohydrates and fat intake have both been linked to development of atherosclerosis. We examined associations between glycemic index (GI) and fat intake with carotid atherosclerosis. The Atherosclerosis Risk in Communities (ARIC) cohort enrolled participants during the period 1987-1989 and the Carotid MRI sub-study occurred between 2004 and 2006 (1672 participants attending both visits). Measures of carbohydrate quality (usual GI), fat intake (total, polyunsaturated and saturated) and overall dietary quality index (DASH Diet Score) were derived from a 66-item food frequency questionnaire administered at baseline. Trained readers measured lipid core presence and maximum wall thickness. Using multivariate logistic regression, we determined the odds of lipid core presence by quintile (Q) of energy-adjusted dietary components. Restricted cubic spline models were used to examine non-linear associations between dietary components and maximum wall thickness. Mean daily polyunsaturated fat intake was 5 g (SD 1.4). GI and polyunsaturated fat intake had a nonlinear relationship with maximum wall thickness. Low (1-4 g) and high (6-12 g) polyunsaturated fat intake were associated with a statistically significant decreased odds of lipid core presence compared to intake in a majority of participants (OR Q5 vs. Q2-4: 0.64, 95% CI 0.42 to 0.98; OR Q1 vs. Q2-4: 0.64, 95% CI 0.42, 0.96), however, the association with lipid core was attenuated by adjustment for maximum wall thickness, hypertension, hyperlipidemia, and diabetes. GI and polyunsaturated fat intake were not associated with high-risk plaque features, such as lipid core presence, independent of traditional vascular risk factors. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Transfer of diazotroph-derived nitrogen towards non-diazotrophic planktonic communities: a comparative study between Trichodesmium erythraeum, Crocosphaera watsonii and Cyanothece sp.

    Science.gov (United States)

    Berthelot, Hugo; Bonnet, Sophie; Grosso, Olivier; Cornet, Véronique; Barani, Aude

    2016-07-01

    Biological dinitrogen (N2) fixation is the major source of new nitrogen (N) for the open ocean, and thus promotes marine productivity, in particular in the vast N-depleted regions of the surface ocean. Yet, the fate of the diazotroph-derived N (DDN) in marine ecosystems is poorly understood, and its transfer to auto- and heterotrophic surrounding plankton communities is rarely measured due to technical limitations. Moreover, the different diazotrophs involved in N2 fixation (Trichodesmium spp. vs. UCYN) exhibit distinct patterns of N2 fixation and inhabit different ecological niches, thus having potentially different fates in the marine food webs that remain to be explored. Here we used nanometer scale secondary ion mass spectrometry (nanoSIMS) coupled with 15N2 isotopic labelling and flow cytometry cell sorting to examine the DDN transfer to specific groups of natural phytoplankton and bacteria during artificially induced diazotroph blooms in New Caledonia (southwestern Pacific). The fate of the DDN was compared according to the three diazotrophs: the filamentous and colony-forming Trichodesmium erythraeum (IMS101), and the unicellular strains Crocosphaera watsonii WH8501 and Cyanothece ATCC51142. After 48 h, 7-17 % of the N2 fixed during the experiment was transferred to the dissolved pool and 6-12 % was transferred to non-diazotrophic plankton. The transfer was twice as high in the T. erythraeum bloom than in the C. watsonii and Cyanothece blooms, which shows that filamentous diazotrophs blooms are more efficient at promoting non-diazotrophic production in N-depleted areas. The amount of DDN released in the dissolved pool did not appear to be a good indicator of the DDN transfer efficiency towards the non-diazotrophic plankton. In contrast, the 15N-enrichment of the extracellular ammonium (NH4+) pool was a good indicator of the DDN transfer efficiency: it was significantly higher in the T. erythraeum than in unicellular diazotroph blooms, leading to a DDN

  18. Environmental transcriptome analysis reveals physiological differences between biofilm and planktonic modes of life of the iron oxidizing bacteria Leptospirillum spp. in their natural microbial community

    Directory of Open Access Journals (Sweden)

    Parro Víctor

    2010-06-01

    Full Text Available Abstract Background Extreme acidic environments are characterized by their high metal content and lack of nutrients (oligotrophy. Macroscopic biofilms and filaments usually grow on the water-air interface or under the stream attached to solid substrates (streamers. In the Río Tinto (Spain, brown filaments develop under the water stream where the Gram-negative iron-oxidizing bacteria Leptospirillum spp. (L. ferrooxidans and L. ferriphilum and Acidithiobacillus ferrooxidans are abundant. These microorganisms play a critical role in bioleaching processes for industrial (biominery and environmental applications (acid mine drainage, bioremediation. The aim of this study was to investigate the physiological differences between the free living (planktonic and the sessile (biofilm associated lifestyles of Leptospirillum spp. as part of its natural extremely acidophilic community. Results Total RNA extracted from environmental samples was used to determine the composition of the metabolically active members of the microbial community and then to compare the biofilm and planktonic environmental transcriptomes by hybridizing to a genomic microarray of L. ferrooxidans. Genes up-regulated in the filamentous biofilm are involved in cellular functions related to biofilm formation and maintenance, such as: motility and quorum sensing (mqsR, cheAY, fliA, motAB, synthesis of cell wall structures (lnt, murA, murB, specific proteases (clpX/clpP, stress response chaperons (clpB, clpC, grpE-dnaKJ, groESL, etc. Additionally, genes involved in mixed acid fermentation (poxB, ackA were up-regulated in the biofilm. This result, together with the presence of small organic acids like acetate and formate (1.36 mM and 0.06 mM respectively in the acidic (pH 1.8 water stream, suggests that either L. ferrooxidans or other member of the microbial community are producing acetate in the acidophilic biofilm under microaerophilic conditions. Conclusions Our results indicate that the

  19. Environmental transcriptome analysis reveals physiological differences between biofilm and planktonic modes of life of the iron oxidizing bacteria Leptospirillum spp. in their natural microbial community.

    Science.gov (United States)

    Moreno-Paz, Mercedes; Gómez, Manuel J; Arcas, Aida; Parro, Víctor

    2010-06-24

    Extreme acidic environments are characterized by their high metal content and lack of nutrients (oligotrophy). Macroscopic biofilms and filaments usually grow on the water-air interface or under the stream attached to solid substrates (streamers). In the Río Tinto (Spain), brown filaments develop under the water stream where the Gram-negative iron-oxidizing bacteria Leptospirillum spp. (L. ferrooxidans and L. ferriphilum) and Acidithiobacillus ferrooxidans are abundant. These microorganisms play a critical role in bioleaching processes for industrial (biominery) and environmental applications (acid mine drainage, bioremediation). The aim of this study was to investigate the physiological differences between the free living (planktonic) and the sessile (biofilm associated) lifestyles of Leptospirillum spp. as part of its natural extremely acidophilic community. Total RNA extracted from environmental samples was used to determine the composition of the metabolically active members of the microbial community and then to compare the biofilm and planktonic environmental transcriptomes by hybridizing to a genomic microarray of L. ferrooxidans. Genes up-regulated in the filamentous biofilm are involved in cellular functions related to biofilm formation and maintenance, such as: motility and quorum sensing (mqsR, cheAY, fliA, motAB), synthesis of cell wall structures (lnt, murA, murB), specific proteases (clpX/clpP), stress response chaperons (clpB, clpC, grpE-dnaKJ, groESL), etc. Additionally, genes involved in mixed acid fermentation (poxB, ackA) were up-regulated in the biofilm. This result, together with the presence of small organic acids like acetate and formate (1.36 mM and 0.06 mM respectively) in the acidic (pH 1.8) water stream, suggests that either L. ferrooxidans or other member of the microbial community are producing acetate in the acidophilic biofilm under microaerophilic conditions. Our results indicate that the acidophilic filaments are dynamic structures

  20. First mesocosm experiments to study the impacts of ocean acidification on plankton communities in the NW Mediterranean Sea (MedSeA project)

    Science.gov (United States)

    Gazeau, F.; Sallon, A.; Maugendre, L.; Louis, J.; Dellisanti, W.; Gaubert, M.; Lejeune, P.; Gobert, S.; Borges, A. V.; Harlay, J.; Champenois, W.; Alliouane, S.; Taillandier, V.; Louis, F.; Obolensky, G.; Grisoni, J.-M.; Guieu, C.

    2017-02-01

    There is a growing international interest in studying the effects of ocean acidification on plankton communities that play a major role in the global carbon cycle and in the consumption of atmospheric CO2 via the so-called biological pump. Recently, several mesocosm experiments reported on the effect of ocean acidification on marine plankton communities, although the majority were performed in eutrophic conditions or following nutrient addition. The objective of the present study was to perform two mesocosm experiments in the oligo- to meso-trophic Northwestern Mediterranean Sea during two seasons with contrasting environmental conditions: in summer 2012 in the Bay of Calvi (Corsica, France) and in winter 2013 in the Bay of Villefranche (France). This paper describes the objectives of these experiments, the study sites, the experimental set-up and the environmental and experimental conditions during the two experiments. The 20-day experiment in the Bay of Calvi was undoubtedly representative of summer conditions in the Northwestern Mediterranean Sea with low nutrient and chlorophyll a concentrations, warm waters and high surface solar irradiance. In contrast, the winter experiment, which was reduced to 12 days because of bad weather conditions, failed to reproduce the mesotrophic conditions typical of the wintertime in this area. Indeed, a rapid increase in phytoplankton biomass during the acidification phase led to a strong decrease in nitrate concentrations and an unrealistic N and P co-limitation at this period of the year. An overview of the 11 other papers related to this study and published in this special issue is provided.

  1. Comprehensive model of annual plankton succession based on the whole-plankton time series approach.

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    Jean-Baptiste Romagnan

    Full Text Available Ecological succession provides a widely accepted description of seasonal changes in phytoplankton and mesozooplankton assemblages in the natural environment, but concurrent changes in smaller (i.e. microbes and larger (i.e. macroplankton organisms are not included in the model because plankton ranging from bacteria to jellies are seldom sampled and analyzed simultaneously. Here we studied, for the first time in the aquatic literature, the succession of marine plankton in the whole-plankton assemblage that spanned 5 orders of magnitude in size from microbes to macroplankton predators (not including fish or fish larvae, for which no consistent data were available. Samples were collected in the northwestern Mediterranean Sea (Bay of Villefranche weekly during 10 months. Simultaneously collected samples were analyzed by flow cytometry, inverse microscopy, FlowCam, and ZooScan. The whole-plankton assemblage underwent sharp reorganizations that corresponded to bottom-up events of vertical mixing in the water-column, and its development was top-down controlled by large gelatinous filter feeders and predators. Based on the results provided by our novel whole-plankton assemblage approach, we propose a new comprehensive conceptual model of the annual plankton succession (i.e. whole plankton model characterized by both stepwise stacking of four broad trophic communities from early spring through summer, which is a new concept, and progressive replacement of ecological plankton categories within the different trophic communities, as recognised traditionally.

  2. Effect of water chemistry on the planktonic communities and relationships among food web components across a freshwater ecotone

    Directory of Open Access Journals (Sweden)

    Mieczan T.

    2013-01-01

    Full Text Available Most ecological research on the food web has been focused more on the pelagic zone than on the transitional zone - ecotones between lentic and lotic habitats. The specific goals of this study were to determine whether the contact zone of waters differs in hydrochemical and biological terms from the waters of the canal and the open water zone, and to evaluate the influence of particular macro-habitats on the interactions between components of the planktonic food web. The distribution of samples in ordination space led us to conclude that the studied habitats are distributed along the rising gradient of total organic carbon and nutrients. Assemblages of all investigated groups showed a strong compositional gradient correlated with conductivity and total phosphorus, while a second strong gradient in species composition was explained by nitrate nitrogen and/or phosphate concentrations. The analysis of trophic relationships in the system bacteriaciliates- crustaceans reveals a clear differentiation and strength of mutual relations between the analyzed zones. The highest number of significant correlations was determined in the contact zone. It can also be a place of very efficient matter and energy flow in freshwater ecosystems.

  3. Assessment of plankton community and environmental conditions in São Sebastião Channel prior to the construction of a produced water outfall

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    Sônia Maria Flores Gianesella

    1999-01-01

    Full Text Available Plankton community and hydrological conditions were assessed as a part of ao environmental diagnosis in São Sebastião Channel, before the building of a submarine outfall of produced water from the oil maritime terminal of PETR08RÁS. Samples were collected in twenty oceanographic stations located in the oil terminal neighboring area, during the springtime of 1991. Oissolved inorganic nutrients and chlorophyll-a concentrations observed indicate an oligo-mesotrophic environment. Phenols and sulfides were absent, 800 values, except for three sampling points, were characteristic of unpolluted environments, although oil and grease were found in half of the sampled stations. Phytoplankton and zooplankton communities presented high diversity and evenness indices for the entire area. Phytoplankton was dominated by phytoflagel1àtes and zooplankton was dominated by copepods, mostly Paracalanus quasimodo. Plankton community composition was similar to that from adjacent regions under low anthropogenic influence.A comunidade planctônica e condições hidrológicas foram avaliadas como parte de um diagnóstico ambiental no Canal de São Sebastião, previamente à construção de um emissário submarino de água de produção, oriunda do terminal marítimo da PETROBRÁS. As amostras foram coletadas em vinte estações oceanográficas situadas na área adjacente ao terminal petrolífero, durante a primavera de 1991. As concentrações de nutrientes inorgânicos dissolvidos e de cIorofila-a obtidas, indicam um ambiente oligo-mesotrófico. Fenóis e sulfetos não foram detectados e os valores de 080, com exceção de três pontos, foram característicos de ambientes não poluídos, apesar da contaminação por óleos e graxas ter sido observada em metade das estações amostradas. O fito e o zooplâncton apresentaram altos índices de diversidade e equitatividade para toda área estudada. O fitoplâncton foi dominado por fitoflagelados, enquanto que o zoopl

  4. Progressive changes in the Western English Channel foster a reorganization in the plankton food web

    DEFF Research Database (Denmark)

    Reygondeau, Gabriel; Molinero, J.C.; Coombs, S.

    2015-01-01

    . (2013) drive a profound restructuration of the plankton community modifying the phenology and the dominance of key planktonic groups including fish larvae. Consequently, the slow but deep modifications detected in the plankton community highlight a climate driven ecosystem shift in the Western English...

  5. Meeting Report: ALTER-Net Workshop about the Application of Molecular Techniques to Study Biodiversity, Structure and Function of Planktonic Communities in Lakes at Blanes, Spain, February 15–16, 2007

    Czech Academy of Sciences Publication Activity Database

    Groben, R.; Hahn, M.W.; Horňák, Karel; Mergeay, J.; Šimek, Karel; Vrba, Jaroslav

    2007-01-01

    Roč. 158, č. 4 (2007), s. 417-421 ISSN 1434-4610 Grant - others:EU(XE) GOCE-CT-2003-505298 Institutional research plan: CEZ:AV0Z60170517 Source of funding: R - rámcový projekt EK Keywords : ALTER-Net * molecular techniques * biodiversity * planktonic communities * lakes Subject RIV: EH - Ecology, Behaviour Impact factor: 3.102, year: 2007

  6. Surface zooplankton communities in the Indian sector of the Antarctic Ocean in early summer 1999/2000 observed with a Continuous Plankton Recorder

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    Haruko Umeda

    2018-05-01

    Full Text Available The first deployment of a Continuous Plankton Recorder (CPR on board the icebreaker Shirase was conducted during the 41st Japanese Antarctic Research Expedition (JARE in 1999/2000 austral summer in the Indian sector of the Antarctic Ocean. The CPR was towed horizontally at approximately 10m depth while the Shirase was steaming at about 14 knots across the Polar Front (PF. Mean total abundance of zooplankton for horizontal five nautical mile sample units was 168.1(SD : ±117.18 individuals with the maximum of 456 individuals. Zooplanktons were counted for 34 categories of species/taxa. Copepods occupied more than 90% of the total abundance in numbers. Oithona spp. was the most dominant group among copepods, representing 59% of the total zooplankton. Other numerically important categories were small-sized calanoids (copepodites and adults; 18.4%, and copepodites of Calanoides acutus and Calanus simillimus (8.2%. Latitudinal change of zooplankton abundance coincided with increasing/decreasing tends of temperature and salinity. Two different zooplankton assemblages were identified by cluster analysis and these assemblages seem to be closely related to different water characteristics, such as the of PF and areas of cold water masses. CPR is considered to be an ideal tool for long term monitoring of surface zooplankton communities.

  7. PSP toxin levels and plankton community composition and abundance in size-fractionated vertical profiles during spring/summer blooms of the toxic dinoflagellate Alexandrium fundyense in the Gulf of Maine and on Georges Bank, 2007, 2008, and 2010: 2. Plankton community composition and abundance.

    Science.gov (United States)

    Petitpas, Christian M; Turner, Jefferson T; Deeds, Jonathan R; Keafer, Bruce A; McGillicuddy, Dennis J; Milligan, Peter J; Shue, Vangie; White, Kevin D; Anderson, Donald M

    2014-05-01

    As part of the Gulf of Maine Toxicity (GOMTOX) project, we determined Alexandrium fundyense abundance, paralytic shellfish poisoning (PSP) toxin levels in various plankton size fractions, and the community composition of potential grazers of A. fundyense in plankton size fractions during blooms of this toxic dinoflagellate in the coastal Gulf of Maine and on Georges Bank in spring and summer of 2007, 2008, and 2010. PSP toxins and A. fundyense cells were found throughout the sampled water column (down to 50 m) in the 20-64 μm size fractions. While PSP toxins were widespread throughout all size classes of the zooplankton grazing community, the majority of the toxin was measured in the 20-64 μm size fraction. A. fundyense cellular toxin content estimated from field samples was significantly higher in the coastal Gulf of Maine than on Georges Bank. Most samples containing PSP toxins in the present study had diverse assemblages of grazers. However, some samples clearly suggested PSP toxin accumulation in several different grazer taxa including tintinnids, heterotrophic dinoflagellates of the genus Protoperidinium , barnacle nauplii, the harpacticoid copepod Microsetella norvegica , the calanoid copepods Calanus finmarchicus and Pseudocalanus spp., the marine cladoceran Evadne nordmanni , and hydroids of the genus Clytia . Thus, a diverse assemblage of zooplankton grazers accumulated PSP toxins through food-web interactions. This raises the question of whether PSP toxins pose a potential human health risk not only from nearshore bivalve shellfish, but also potentially from fish and other upper-level consumers in zooplankton-based pelagic food webs.

  8. Distribution and production of plankton communities in the subtropical convergence zone of the Sargasso Sea. II. Protozooplankton and copepods

    DEFF Research Database (Denmark)

    Andersen, Nikolaj G.; Nielsen, Torkel Gissel; Jakobsen, Hans Henrik

    2011-01-01

    the potential reasons why Atlantic eels Anguilla spp. use this area for spawning, we investigated the distribution and productivity of the zooplankton community across the Subtropical Convergence Zone (STCZ) in the Sargasso Sea in March and April 2007. The vertical and horizontal distributions of protozoans...

  9. Linking phytoplankton community size composition with temperature, plankton food web structure and sea–air CO2 flux

    DEFF Research Database (Denmark)

    Hilligsøe, Karen Marie; Richardson, Katherine; Bendtsen, Jørgen

    2011-01-01

    Data collected at open water stations (depth>400m) in all major ocean basins in 2006–2008 are used to examine the relationship between the size structure of the phytoplankton community (determined by size fractionated chlorophyll filtration), temperature and inorganic nutrient availability...

  10. Abundance and size structure of planktonic protist communities in a Neotropical floodplain: effects of top-down and bottom-up controls

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    Bianca Ramos de Meira

    2017-12-01

    Full Text Available Abstract: Aim: We aimed to assess the influence of bottom-up and top-down control mechanisms on the abundance and size structure of protist communities (heterotrophic flagellates and ciliates. We formulated the following hypothesis: bottom-up control mechanisms, related to the availability of resources in the environment, are responsible for structuring the abundance of these communities, whereas top-down control mechanisms, related to predation effects, determine the size pattern of these organisms. Methods Samples for planktonic organisms were taken in 20 shallow lakes belonging to the upper Paraná River floodplain. We evaluated linear regression models to select the best model which predicts the patterns observed according to Akaike Information Criterion. Results The best models selected to explain the abundance of heterotrophic flagellates included negative relations with picophytoplankton abundance and positive with rotifers abundance, while for their size structure, negative relationships were found with heterotrophic bacteria, ciliates and rotifers biovolumes. In relation to the ciliates, their abundances were positively related to the rotifers and picophytoplankton abundances and negatively with the heterotrophic bacteria abundance. On the other hand, for the size structure, the best models selected strong negative relations with the microcrustaceans biovolumes, in addition to relations with the different fractions of the phytoplankton. Conclusion For both flagellates and ciliates, their abundance is being mainly regulated by a bottom up control mechanism, whereas for the size structure the results showed that both food resources and predators were important, indicating that bottom-up and top-down mechanisms act simultaneously in determining the size of these microorganisms.

  11. Effects of silver nitrate and silver nanoparticles on a planktonic community: general trends after short-term exposure.

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    Jens Boenigk

    Full Text Available Among metal pollutants silver ions are one of the most toxic forms, and have thus been assigned to the highest toxicity class. Its toxicity to a wide range of microorganisms combined with its low toxicity to humans lead to the development of a wealth of silver-based products in many bactericidal applications accounting to more than 1000 nano-technology-based consumer products. Accordingly, silver is a widely distributed metal in the environment originating from its different forms of application as metal, salt and nanoparticle. A realistic assessment of silver nanoparticle toxicity in natural waters is, however, problematic and needs to be linked to experimental approaches. Here we apply metatranscriptome sequencing allowing for elucidating reactions of whole communities present in a water sample to stressors. We compared the toxicity of ionic silver and ligand-free silver nanoparticles by short term exposure on a natural community of aquatic microorganisms. We analyzed the effects of the treatments on metabolic pathways and species composition on the eukaryote metatranscriptome level in order to describe immediate molecular responses of organisms using a community approach. We found significant differences between the samples treated with 5 µg/L AgNO3 compared to the controls, but no significant differences in the samples treated with AgNP compared to the control samples. Statistical analysis yielded 126 genes (KO-IDs with significant differential expression with a false discovery rate (FDR <0.05 between the control (KO and AgNO3 (NO3 groups. A KEGG pathway enrichment analysis showed significant results with a FDR below 0.05 for pathways related to photosynthesis. Our study therefore supports the view that ionic silver rather than silver nanoparticles are responsible for silver toxicity. Nevertheless, our results highlight the strength of metatranscriptome approaches for assessing metal toxicity on aquatic communities.

  12. Role of Fusobacterium nucleatum and Coaggregation in Anaerobe Survival in Planktonic and Biofilm Oral Microbial Communities during Aeration

    OpenAIRE

    Bradshaw, David J.; Marsh, Philip D.; Watson, G. Keith; Allison, Clive

    1998-01-01

    Coaggregation is a well-characterized phenomenon by which specific pairs of oral bacteria interact physically. The aim of this study was to examine the patterns of coaggregation between obligately anaerobic and oxygen-tolerant species that coexist in a model oral microbial community. Obligate anaerobes other than Fusobacterium nucleatum coaggregated only poorly with oxygen-tolerant species. In contrast, F. nucleatum was able to coaggregate not only with both oxygen-tolerant and other obligate...

  13. Counting carbohydrates

    Science.gov (United States)

    Carb counting; Carbohydrate-controlled diet; Diabetic diet; Diabetes-counting carbohydrates ... Many foods contain carbohydrates (carbs), including: Fruit and fruit juice Cereal, bread, pasta, and rice Milk and milk products, soy milk Beans, legumes, ...

  14. A Synoptic Assessment of the Amazon River-Ocean Continuum during Boreal Autumn: From Physics to Plankton Communities and Carbon Flux

    Science.gov (United States)

    Araujo, Moacyr; Noriega, Carlos; Hounsou-gbo, Gbekpo Aubains; Veleda, Doris; Araujo, Julia; Bruto, Leonardo; Feitosa, Fernando; Flores-Montes, Manuel; Lefèvre, Nathalie; Melo, Pedro; Otsuka, Amanda; Travassos, Keyla; Schwamborn, Ralf; Neumann-Leitão, Sigrid

    2017-01-01

    The Amazon generates the world's largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly NO3− and SiO2−, were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m−3). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO2 fugacity (fCO2sw), calculated from total alkalinity (1,450 35 and higher-intensity winds, the CO2 flux is reversed. Lower fCO2sw values were observed in the NECC area. The ΔfCO2 in this region was less than 5 μatm (−0.3 mmol m−2 d−1), while the ΔfCO2 in the coastal region was

  15. A Synoptic Assessment of the Amazon River-Ocean Continuum during Boreal Autumn: From Physics to Plankton Communities and Carbon Flux.

    Science.gov (United States)

    Araujo, Moacyr; Noriega, Carlos; Hounsou-Gbo, Gbekpo Aubains; Veleda, Doris; Araujo, Julia; Bruto, Leonardo; Feitosa, Fernando; Flores-Montes, Manuel; Lefèvre, Nathalie; Melo, Pedro; Otsuka, Amanda; Travassos, Keyla; Schwamborn, Ralf; Neumann-Leitão, Sigrid

    2017-01-01

    The Amazon generates the world's largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly [Formula: see text] and [Formula: see text], were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m -3 ). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO 2 fugacity (fCO 2 sw), calculated from total alkalinity (1,450 35 and higher-intensity winds, the CO 2 flux is reversed. Lower fCO 2 sw values were observed in the NECC area. The ΔfCO 2 in this region was less than 5 μatm (-0.3 mmol m -2 d -1 ), while the ΔfCO 2 in the

  16. A Synoptic Assessment of the Amazon River-Ocean Continuum during Boreal Autumn: From Physics to Plankton Communities and Carbon Flux

    Directory of Open Access Journals (Sweden)

    Moacyr Araujo

    2017-07-01

    Full Text Available The Amazon generates the world's largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC. The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly NO3− and SiO2−, were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization. In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m−3. The North Equatorial Counter Current (NECC region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods. A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO2 fugacity (fCO2sw, calculated from total alkalinity (1,450 < TA < 2,394 μmol kg−1 and dissolved inorganic carbon (1,303 < DIC < 2,062 μmol kg−1 measurements, confirms that the Amazon River plume is a sink of atmospheric CO2 in areas with salinities <35 psu, whereas, in regions

  17. Effects of the global changes on the aquatic ecosystems in West Europe - role of the plankton communities; Effets des changements globaux sur les ecosystemes aquatiques d'Europe Occidentale - role des communautes planctoniques

    Energy Technology Data Exchange (ETDEWEB)

    Souissi, S. [Universite des Sciences et Technologies de Lille, Ecosystem COmplexity REsearch Group, Station Marine de Wimereux, CNRS - FRE 2816 ELICO, 62 - Wimereux (France)

    2007-07-01

    Examination of long-term records of aquatic ecosystems has provided useful information to find out their major driving forces. Understanding the impact of climate change on these ecosystems, the management of their resources and the extrapolation between sites are the main scopes of actual and emerging studies. Such goals can be achieved by inter-site and inter-ecosystem comparisons. This approach was undertaken during our project which has the originality to tackle with marine and freshwater ecosystems. It allowed us to compile and validate several multi-decadal time series of planktonic and other physical driving forces at local and regional scales. Then, the same methodology based on the analysis of the variability of climate indices and biological data across several spatial scales was used. The different ecosystems analyzed here showed clear response to the North Atlantic climate variability. Although the local differences abrupt changes in community composition occurred in all ecosystems in the middle of the years 80. During this period there was also a major shift in climatic conditions during winter and early spring, suggesting an impact of climatic factors. Phenological changes were also observed in plankton communities in all sites. The consequences of the modifications of plankton dynamics on higher trophic levels were also showed. Fluctuations in plankton have resulted in long-term changes in cod recruitment in the North Sea (bottom-up control). On the other hand, both climate change and the improvement of trophic status in Geneva Lake favored the outbreak of whitefish during the years 90. Lower larval mortality and better recruitment are supposed to be linked to faster growth associated with warmer temperatures and better food conditions induced by better temporal overlap between larvae hatching and zooplankton development. (author)

  18. Interannual control of plankton communities by deep winter mixing and prey/predator interactions in the NW Mediterranean: Results from a 30-year 3D modeling study

    Science.gov (United States)

    Auger, P. A.; Ulses, C.; Estournel, C.; Stemmann, L.; Somot, S.; Diaz, F.

    2014-05-01

    A realistic modeling approach is designed to address the role of winter mixing on the interannual variability of plankton dynamics in the north-western (NW) Mediterranean basin. For the first time, a high-resolution coupled hydrodynamic-biogeochemical model (Eco3m-S) covering a 30-year period (1976-2005) is validated on available in situ and satellite data for the NW Mediterranean. In this region, cold, dry winds in winter often lead to deep convection and strong upwelling of nutrients into the euphotic layer. High nutrient contents at the end of winter then support the development of a strong spring bloom of phytoplankton. Model results indicate that annual primary production is not affected by winter mixing due to seasonal balance (minimum in winter and maximum in spring). However, the total annual water column-integrated phytoplankton biomass appears to be favored by winter mixing because zooplankton grazing activity is low in winter and early spring. This reduced grazing is explained here by the rarefaction of prey due to both light limitation and the effect of mixing-induced dilution on prey/predator interactions. A negative impact of winter mixing on winter zooplankton biomass is generally simulated except for mesozooplankton. This difference is assumed to stem from the lower parameterized mortality, top trophic position and detritivorous diet of mesozooplankton in the model. Moreover, model suggests that the variability of annual mesozooplankton biomass is principally modulated by the effects of winter mixing on winter biomass. Thus, interannual variability of winter nutrient contents in the euphotic layer, resulting from winter mixing, would control spring primary production and thus annual mesozooplankton biomass. Our results show a bottom-up control of mesozooplankton communities, as observed at a coastal location of the Ligurian Sea.

  19. Basin-scale variability in plankton biomass and community metabolism in the sub-tropical North Atlantic Ocean

    Science.gov (United States)

    Harrison, W. G.; Arístegui, J.; Head, E. J. H.; Li, W. K. W.; Longhurst, A. R.; Sameoto, D. D.

    Three trans-Atlantic oceanographic surveys (Nova Scotia to Canary Islands) were carried out during fall 1992 and spring 1993 to describe the large-scale variability in hydrographic, chemical and biological properties of the upper water column of the subtropical gyre and adjacent waters. Significant spatial and temporal variability characterized a number of the biological pools and rate processes whereas others were relatively invariant. Systematic patterns were observed in the zonal distribution of some properties. Most notable were increases (eastward) in mixed-layer temperature and salinity, depths of the nitracline and chlorophyll- a maximum, regenerated production (NH 4 uptake) and bacterial production. Dissolved inorganic carbon (DIC) concentrations, phytoplankton biomass, mesozooplankton biomass and new production (NO 3 uptake) decreased (eastward). Bacterial biomass, primary production, and community respiration exhibited no discernible zonal distribution patterns. Seasonal variability was most evident in hydrography (cooler/fresher mixed-layer in spring), and chemistry (mixed-layer DIC concentration higher and nitracline shallower in spring) although primary production and bacterial production were significantly higher in spring than in fall. In general, seasonal variability was greater in the west than in the east; seasonality in most properties was absent west of Canary Islands (˜20°W). The distribution of autotrophs could be reasonably well explained by hydrography and nutrient structure, independent of location or season. Processes underlying the distribution of the microheterophs, however, were less clear. Heterotrophic biomass and metabolism was less variable than autotrophs and appeared to dominate the upper ocean carbon balance of the subtropical North Atlantic in both fall and spring. Geographical patterns in distribution are considered in the light of recent efforts to partition the ocean into distinct "biogeochemical provinces".

  20. Trophic condition of the volcanic Lake Nemi (Central Italy: environmental factors and planktonic communities in a changing environment

    Directory of Open Access Journals (Sweden)

    Fiorenza G. MARGARITORA

    2005-08-01

    Full Text Available Lake Nemi is an interesting case of anthropogenic overexploitation which has caused its progressive environmental deterioration in the past decades. On this lake historical data about the trophic situation are available from 1975 to 1984. The research performed in 2002-03, about ten years after the diversion of urban waste waters, concerned a biological investigation on the phyto- and zooplanktonic communities, integrated with a physico-chemical analysis. The aims of our study are to evaluate the current water quality of the lake and compare it with the water quality observed in 1982-1983, when all biotic and abiotic components indicated a heavily compromised hypereutrophic condition. The water quality data and the comparison with a previous study point out that the biological aspects have partially changed (increased number of Cyanobacteria and phytoplanktonic taxa, particularly Clorophyta and Dinophyta; zooplankton composition changed at a species level, with the appearance of taxa associated to light trophic conditions, and the physico-chemical conditions significantly improved. The mean transparency, dissolved oxygen, nutrients and chlorophyll-a concentrations have all improved. Mean annual temperature at different depths increased, probably due to differences in climatic period and the lowering of the lake surface level (from 32.5 to 27.5 m in 1982 and 2002, respectively. Our results indicate a general improving trend in water quality is taking place since the diversion of waste water discharges. The present abiotic characteristics of the lake allow the phytoplankton to distribute itself in the whole epilimnion, and the zooplankton in the whole water column. A possible further improvement is hypothesized, and the constraints represented by excessive water level lowering and water temperature increasing are also discussed.

  1. Bioprospecting Marine Plankton

    Directory of Open Access Journals (Sweden)

    Chris Bowler

    2013-11-01

    Full Text Available The ocean dominates the surface of our planet and plays a major role in regulating the biosphere. For example, the microscopic photosynthetic organisms living within provide 50% of the oxygen we breathe, and much of our food and mineral resources are extracted from the ocean. In a time of ecological crisis and major changes in our society, it is essential to turn our attention towards the sea to find additional solutions for a sustainable future. Remarkably, while we are overexploiting many marine resources, particularly the fisheries, the planktonic compartment composed of zooplankton, phytoplankton, bacteria and viruses, represents 95% of marine biomass and yet the extent of its diversity remains largely unknown and underexploited. Consequently, the potential of plankton as a bioresource for humanity is largely untapped. Due to their diverse evolutionary backgrounds, planktonic organisms offer immense opportunities: new resources for medicine, cosmetics and food, renewable energy, and long-term solutions to mitigate climate change. Research programs aiming to exploit culture collections of marine micro-organisms as well as to prospect the huge resources of marine planktonic biodiversity in the oceans are now underway, and several bioactive extracts and purified compounds have already been identified. This review will survey and assess the current state-of-the-art and will propose methodologies to better exploit the potential of marine plankton for drug discovery and for dermocosmetics.

  2. Plankton biodiversity of Dharamtar creek adjoining Mumbai harbour

    Digital Repository Service at National Institute of Oceanography (India)

    Tiwari, L.R.; Nair, V.R.

    rich plankton community. However, recent industrial development along the banks of creek may pose the problem due to waste disposal into this creek system. Losses of marine life diversity are largely the results of conflicting uses, in particular...

  3. Carbohydrate microarrays

    DEFF Research Database (Denmark)

    Park, Sungjin; Gildersleeve, Jeffrey C; Blixt, Klas Ola

    2012-01-01

    In the last decade, carbohydrate microarrays have been core technologies for analyzing carbohydrate-mediated recognition events in a high-throughput fashion. A number of methods have been exploited for immobilizing glycans on the solid surface in a microarray format. This microarray...... of substrate specificities of glycosyltransferases. This review covers the construction of carbohydrate microarrays, detection methods of carbohydrate microarrays and their applications in biological and biomedical research....

  4. Large-scale ocean connectivity and planktonic body size

    KAUST Repository

    Villarino, Ernesto

    2018-01-04

    Global patterns of planktonic diversity are mainly determined by the dispersal of propagules with ocean currents. However, the role that abundance and body size play in determining spatial patterns of diversity remains unclear. Here we analyse spatial community structure - β-diversity - for several planktonic and nektonic organisms from prokaryotes to small mesopelagic fishes collected during the Malaspina 2010 Expedition. β-diversity was compared to surface ocean transit times derived from a global circulation model, revealing a significant negative relationship that is stronger than environmental differences. Estimated dispersal scales for different groups show a negative correlation with body size, where less abundant large-bodied communities have significantly shorter dispersal scales and larger species spatial turnover rates than more abundant small-bodied plankton. Our results confirm that the dispersal scale of planktonic and micro-nektonic organisms is determined by local abundance, which scales with body size, ultimately setting global spatial patterns of diversity.

  5. Large-scale ocean connectivity and planktonic body size

    KAUST Repository

    Villarino, Ernesto; Watson, James R.; Jö nsson, Bror; Gasol, Josep M.; Salazar, Guillem; Acinas, Silvia G.; Estrada, Marta; Massana, Ramó n; Logares, Ramiro; Giner, Caterina R.; Pernice, Massimo C.; Olivar, M. Pilar; Citores, Leire; Corell, Jon; Rodrí guez-Ezpeleta, Naiara; Acuñ a, José Luis; Molina-Ramí rez, Axayacatl; Gonzá lez-Gordillo, J. Ignacio; Có zar, André s; Martí , Elisa; Cuesta, José A.; Agusti, Susana; Fraile-Nuez, Eugenio; Duarte, Carlos M.; Irigoien, Xabier; Chust, Guillem

    2018-01-01

    Global patterns of planktonic diversity are mainly determined by the dispersal of propagules with ocean currents. However, the role that abundance and body size play in determining spatial patterns of diversity remains unclear. Here we analyse spatial community structure - β-diversity - for several planktonic and nektonic organisms from prokaryotes to small mesopelagic fishes collected during the Malaspina 2010 Expedition. β-diversity was compared to surface ocean transit times derived from a global circulation model, revealing a significant negative relationship that is stronger than environmental differences. Estimated dispersal scales for different groups show a negative correlation with body size, where less abundant large-bodied communities have significantly shorter dispersal scales and larger species spatial turnover rates than more abundant small-bodied plankton. Our results confirm that the dispersal scale of planktonic and micro-nektonic organisms is determined by local abundance, which scales with body size, ultimately setting global spatial patterns of diversity.

  6. Carbohydrate Analysis

    Science.gov (United States)

    Bemiller, James N.

    Carbohydrates are important in foods as a major source of energy, to impart crucial textural properties, and as dietary fiber which influences physiological processes. Digestible carbohydrates, which are converted into monosaccharides, which are absorbed, provide metabolic energy. Worldwide, carbohydrates account for more than 70% of the caloric value of the human diet. It is recommended that all persons should limit calories from fat (the other significant source) to not more than 30% and that most of the carbohydrate calories should come from starch. Nondigestible polysaccharides (all those other than starch) comprise the major portion of dietary fiber (Sect. 10.5). Carbohydrates also contribute other attributes, including bulk, body, viscosity, stability to emulsions and foams, water-holding capacity, freeze-thaw stability, browning, flavors, aromas, and a range of desirable textures (from crispness to smooth, soft gels). They also provide satiety. Basic carbohydrate structures, chemistry, and terminology can be found in references (1, 2).

  7. Plankton food-webs: to what extent can they be simplified?

    Directory of Open Access Journals (Sweden)

    Domenico D'Alelio

    2016-05-01

    Full Text Available Plankton is a hugely diverse community including both unicellular and multicellular organisms, whose individual dimensions span over seven orders of magnitude. Plankton is a fundamental part of biogeochemical cycles and food-webs in aquatic systems. While knowledge has progressively accumulated at the level of single species and single trophic processes, the overwhelming biological diversity of plankton interactions is insufficiently known and a coherent and unifying trophic framework is virtually lacking. We performed an extensive review of the plankton literature to provide a compilation of data suitable for implementing food-web models including plankton trophic processes at high taxonomic resolution. We identified the components of the plankton community at the Long Term Ecological Research Station MareChiara in the Gulf of Naples. These components represented the sixty-three nodes of a plankton food-web. To each node we attributed biomass and vital rates, i.e. production, consumption, assimilation rates and ratio between autotrophy and heterotrophy in mixotrophic protists. Biomasses and rates values were defined for two opposite system’s conditions; relatively eutrophic and oligotrophic states. We finally identified 817 possible trophic links within the web and provided each of them with a relative weight, in order to define a diet-matrix, valid for both trophic states, which included all consumers, fromn anoflagellates to carnivorous plankton. Vital rates for plankton resulted, as expected, very wide; this strongly contrasts with the narrow ranges considered in plankton system models implemented so far. Moreover, the amount and variety of trophic links highlighted by our review is largely excluded by state-of-the-art biogeochemical and food-web models for aquatic systems. Plankton models could potentially benefit from the integration of the trophic diversity outlined in this paper: first, by using more realistic rates; second, by better

  8. Seasonal patterns in plankton communities in a pluriannual time series at a coastal Mediterranean site (Gulf of Naples: an attempt to discern recurrences and trends

    Directory of Open Access Journals (Sweden)

    M. Ribera d'Alcalà

    2004-04-01

    Full Text Available The annual cycle of plankton was studied over 14 years from 1984 to 2000 at a coastal station in the Gulf of Naples, with the aim of assessing seasonal patterns and interannual trends. Phytoplankton biomass started increasing over the water column in February-early March, and generally achieved peak values in the upper layers in late spring. Another peak was often recorded in autumn. Diatoms and phytoflagellates dominated for the largest part of the year. Ciliates showed their main peaks in phase with phytoplankton and were mainly represented by small (< 30 mm naked choreotrichs. Mesozooplankton increased in March-April, reaching maximum concentrations in summer. Copepods were always the most abundant group, followed by cladocerans in summer. At the interannual scale, a high variability and a decreasing trend were recorded over the sampling period for autotrophic biomass. Mesozooplankton biomass showed a less marked interannual variability. From 1995 onwards, phytoplankton populations increased in cell number but decreased in cell size, with intense blooms of small diatoms and undetermined coccoid species frequently observed in recent years. In spite of those interannual variations, the different phases of the annual cycle and the occurrence of several plankton species were remarkably regular.

  9. Carbohydrate Loading.

    Science.gov (United States)

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  10. Increasing Water Temperature Triggers Dominance of Small Freshwater Plankton.

    Science.gov (United States)

    Rasconi, Serena; Gall, Andrea; Winter, Katharina; Kainz, Martin J

    2015-01-01

    Climate change scenarios predict that lake water temperatures will increase up to 4°C and rainfall events will become more intense and frequent by the end of this century. Concurrently, supply of humic substances from terrestrial runoff is expected to increase, resulting in darker watercolor ("brownification") of aquatic ecosystems. Using a multi-seasonal, low trophic state mesocosm experiment, we investigated how higher water temperature and brownification affect plankton community composition, phenology, and functioning. We tested the hypothesis that higher water temperature (+3°C) and brownification will, a) cause plankton community composition to shift toward small sized phytoplankton and cyanobacteria, and, b) extend the length of the growing season entailing higher phytoplankton production later in the season. We demonstrate that the 3°C increase of water temperature favored the growth of heterotrophic bacteria and small sized autotrophic picophytoplankton cells with significantly higher primary production during warmer fall periods. However, 3X darker water (effect of brownification) caused no significant changes in the plankton community composition or functioning relative to control conditions. Our findings reveal that increased temperature change plankton community structure by favoring smaller sized species proliferation (autotrophic phytoplankton and small size cladocerans), and increase primary productivity and community turnover. Finally, results of this multi-seasonal experiment suggest that warming by 3°C in aquatic ecosystems of low trophic state may cause planktonic food web functioning to become more dominated by fast growing, r-trait species (i.e., small sizes and rapid development).

  11. The Partitioning of Carbon Biomass among the Pico- and Nano-plankton Community in the South Brazilian Bight during a Strong Summer Intrusion of South Atlantic Central Water

    Directory of Open Access Journals (Sweden)

    Natascha M. Bergo

    2017-07-01

    Full Text Available To investigate how pico- and nano-plankton respond to oceanographic conditions in the Southwestern Atlantic Ocean, we assessed the influence of a summer intrusion of the South Atlantic Central Water (SACW on the spatial and vertical dynamics of planktonic abundance and carbon biomass across environmental gradients. Seawater samples were collected from six depths within the euphotic zone at nine oceanographic stations in a transect on the Brazilian continental shelf in January 2013. The abundance of pico- and nano-plankton populations was determined by flow cytometry, and carbon biomass was calculated based on conversion factors from the literature. The autotrophic Synechococcus spp., picoeukaryotes, and nanoeukaryotes were more abundant in the surface layers of the innermost stations influenced by Coastal Water (maximum of 1.19 × 105, 1.5 × 104, and 8.61 × 103 cell·mL−1, respectively, whereas Prochlorococcus spp. dominated (max. of 6.57 × 104 cell·mL−1 at the outermost stations influenced by Tropical Water and in the uplifting layers of the SACW around a depth of 100 m. Numerically, heterotrophic bacterial populations were predominant, with maximum concentrations (2.11 × 106 cell·mL−1 recorded in the surface layers of the inner and mid shelves in Coastal Water and the upper limits of the SACW. Nutrient-rich (high silicate and phosphate and relatively less saline waters enhanced the picoeukaryotic biomass, while Synechococcus and heterotrophic bacteria were linked to higher temperatures, lower salinities, and higher inputs of ammonia and dissolved organic carbon. The relative importance of each group to carbon biomass partitioning under upwelling conditions is led by heterotrophic bacteria, followed by picoeukaryotes, Synechococcus and Prochlorococcus, and when the SACW is not as influential, the relative contribution of each phytoplanktonic group is more evenly distributed. In addition to habitat preferences, the physical structure

  12. Plankton dynamics associated with the convergence zone of a shear ...

    African Journals Online (AJOL)

    Multiple linear regression was used to determine the relationships between water quality variables and plankton abundances. Community analysis was also run on the data in order to determine community dynamics associated with frontal system convergence and downwelling. Key words: ichthyoplankton, phytoplankton, ...

  13. Carbohydrate malabsorption

    DEFF Research Database (Denmark)

    Rumessen, J J; Nordgaard-Andersen, I; Gudmand-Høyer, E

    1994-01-01

    Previous studies in small series of healthy adults have suggested that parallel measurement of hydrogen and methane resulting from gut fermentation may improve the precision of quantitative estimates of carbohydrate malabsorption. Systematic, controlled studies of the role of simultaneous hydrogen...

  14. Effects of pectin on fermentation characteristics, carbohydrate utilization, and microbial community composition in the gastrointestinal tract of weaning pigs

    NARCIS (Netherlands)

    Tian, Lingmin; Bruggeman, Geert; van den Berg, Marco; Borewicz, Klaudyna; Scheurink, Anton J. W.; Bruininx, Erik; de Vos, Paul; Smidt, Hauke; Schols, Henk A.; Gruppen, Harry

    Scope: We aimed to investigate the effects of three different soluble pectins on the digestion of other consumed carbohydrates, and the consequent alterations of microbiota composition and SCFA levels in the intestine of pigs. Methods and results: Piglets were fed a low-methyl esterified pectin

  15. Origin of marine planktonic cyanobacteria.

    Science.gov (United States)

    Sánchez-Baracaldo, Patricia

    2015-12-01

    Marine planktonic cyanobacteria contributed to the widespread oxygenation of the oceans towards the end of the Pre-Cambrian and their evolutionary origin represents a key transition in the geochemical evolution of the Earth surface. Little is known, however, about the evolutionary events that led to the appearance of marine planktonic cyanobacteria. I present here phylogenomic (135 proteins and two ribosomal RNAs), Bayesian relaxed molecular clock (18 proteins, SSU and LSU) and Bayesian stochastic character mapping analyses from 131 cyanobacteria genomes with the aim to unravel key evolutionary steps involved in the origin of marine planktonic cyanobacteria. While filamentous cell types evolved early on at around 2,600-2,300 Mya and likely dominated microbial mats in benthic environments for most of the Proterozoic (2,500-542 Mya), marine planktonic cyanobacteria evolved towards the end of the Proterozoic and early Phanerozoic. Crown groups of modern terrestrial and/or benthic coastal cyanobacteria appeared during the late Paleoproterozoic to early Mesoproterozoic. Decrease in cell diameter and loss of filamentous forms contributed to the evolution of unicellular planktonic lineages during the middle of the Mesoproterozoic (1,600-1,000 Mya) in freshwater environments. This study shows that marine planktonic cyanobacteria evolved from benthic marine and some diverged from freshwater ancestors during the Neoproterozoic (1,000-542 Mya).

  16. The effects of the Sea Empress oil spill on the plankton of the southern Irish Sea

    International Nuclear Information System (INIS)

    Batten, S.; Allen, R.; Wotton, C.

    1997-07-01

    This report describes the methodology used to determine any effects of the Sea Empress oil spill on the plankton communities of the southern Irish Sea. The Continuous Plankton Recorder (CPR) survey has monitored the plankton in this area since 1970 so there is a long time series of data collected before the spill, almost 2000 samples, with which to compare the post-spill data. The analytical procedures applied and results obtained are presented and reveal that in the majority of cases no significant effects were evident. Some exceptions are also described. The results suggest that no further analysis of the plankton communities is necessary, unless other studies reveal that other marine habitats which may have an influence on the plankton of this area are continuing to display effects of the spill. There is scope for further investigation of the trends and events described in this report but this is outside the remit of the project. (author)

  17. Learning about Carbohydrates

    Science.gov (United States)

    ... Videos for Educators Search English Español Learning About Carbohydrates KidsHealth / For Kids / Learning About Carbohydrates Print en ... source of energy for the body. What Are Carbohydrates? There are two major types of carbohydrates (or ...

  18. The ecological competition and grazing reverse the effects of sulfamethoxazole on plankton: a case study on characterizing community-level effect.

    Science.gov (United States)

    Wang, Changyou; Liang, Shengkang; Zhang, Yong

    2018-04-12

    The toxic effects of sulfamethoxazole (SMX) on densities of two algae, Platymonas helgolandica var. tsingtaoensis, Isochrysis galbana, and of a rotifer, Brachionus plicatilis, were tested by the population and community experiments. Two endpoints, the carrying capacity and the densities array of community in steady state (DACS), were used to characterize the toxic effects at a population level and a community one, respectively. The results showed that the carrying capacity of P. helgolandica var. tsingtaoensis and B. plicatilis did not decline significantly in population test when the concentration of SMX was lower than 6.0 mg L -1 and 12.0 mg L -1 , respectively. However, I. galbana was sensitive to SMX and had presented toxic effect at 3.0 mg L -1 . By extrapolation of toxic effect at a population level to a community one, a derived community-NOEC was 3.0 mg L -1 , representing an inference from data of toxic effects at population level. In community experiment, when the customized community was in steady state, the density of I. galbana increased as a whole with SMX concentration in the range of tested concentration (0-144 mg L -1 ), while that of P. helgolandica var. tsingtaoensis assumed the trend of a reversed "v" in this range. Only the density of B. plicatilis decreased with SMX concentration. With the DACS as endpoint, a NOEC for the customized community was determined to be 6.0 mg L -1 . This indicates that interspecific interactions can reverse the toxic effects of SMX on phytoplankton. The DACS was reliable and stable, serving as the endpoints in assessment of the effects of the pollutants on the ecosystems.

  19. Identification of major planktonic sulfur oxidizers in stratified freshwater lake.

    Directory of Open Access Journals (Sweden)

    Hisaya Kojima

    Full Text Available Planktonic sulfur oxidizers are important constituents of ecosystems in stratified water bodies, and contribute to sulfide detoxification. In contrast to marine environments, taxonomic identities of major planktonic sulfur oxidizers in freshwater lakes still remain largely unknown. Bacterioplankton community structure was analyzed in a stratified freshwater lake, Lake Mizugaki in Japan. In the clone libraries of 16S rRNA gene, clones very closely related to a sulfur oxidizer isolated from this lake, Sulfuritalea hydrogenivorans, were detected in deep anoxic water, and occupied up to 12.5% in each library of different water depth. Assemblages of planktonic sulfur oxidizers were specifically analyzed by constructing clone libraries of genes involved in sulfur oxidation, aprA, dsrA, soxB and sqr. In the libraries, clones related to betaproteobacteria were detected with high frequencies, including the close relatives of Sulfuritalea hydrogenivorans.

  20. Increasing Water Temperature Triggers Dominance of Small Freshwater Plankton.

    Directory of Open Access Journals (Sweden)

    Serena Rasconi

    Full Text Available Climate change scenarios predict that lake water temperatures will increase up to 4°C and rainfall events will become more intense and frequent by the end of this century. Concurrently, supply of humic substances from terrestrial runoff is expected to increase, resulting in darker watercolor ("brownification" of aquatic ecosystems. Using a multi-seasonal, low trophic state mesocosm experiment, we investigated how higher water temperature and brownification affect plankton community composition, phenology, and functioning. We tested the hypothesis that higher water temperature (+3°C and brownification will, a cause plankton community composition to shift toward small sized phytoplankton and cyanobacteria, and, b extend the length of the growing season entailing higher phytoplankton production later in the season. We demonstrate that the 3°C increase of water temperature favored the growth of heterotrophic bacteria and small sized autotrophic picophytoplankton cells with significantly higher primary production during warmer fall periods. However, 3X darker water (effect of brownification caused no significant changes in the plankton community composition or functioning relative to control conditions. Our findings reveal that increased temperature change plankton community structure by favoring smaller sized species proliferation (autotrophic phytoplankton and small size cladocerans, and increase primary productivity and community turnover. Finally, results of this multi-seasonal experiment suggest that warming by 3°C in aquatic ecosystems of low trophic state may cause planktonic food web functioning to become more dominated by fast growing, r-trait species (i.e., small sizes and rapid development.

  1. Models of Plankton Community Changes during a Warm Water Anomaly in Arctic Waters Show Altered Trophic Pathways with Minimal Changes in Carbon Export

    Directory of Open Access Journals (Sweden)

    Maria Vernet

    2017-05-01

    Full Text Available Carbon flow through pelagic food webs is an expression of the composition, biomass and activity of phytoplankton as primary producers. In the near future, severe environmental changes in the Arctic Ocean are expected to lead to modifications of phytoplankton communities. Here, we used a combination of linear inverse modeling and ecological network analysis to study changes in food webs before, during, and after an anomalous warm water event in the eastern Fram Strait of the West Spitsbergen Current (WSC that resulted in a shift from diatoms to flagellates during the summer (June–July. The model predicts substantial differences in the pathways of carbon flow in diatom- vs. Phaeocystis/nanoflagellate-dominated phytoplankton communities, but relatively small differences in carbon export. The model suggests a change in the zooplankton community and activity through increasing microzooplankton abundance and the switching of meso- and macrozooplankton feeding from strict herbivory to omnivory, detritivory and coprophagy. When small cells and flagellates dominated, the phytoplankton carbon pathway through the food web was longer and the microbial loop more active. Furthermore, one step was added in the flow from phytoplankton to mesozooplankton, and phytoplankton carbon to higher trophic levels is available via detritus or microzooplankton. Model results highlight how specific changes in phytoplankton community composition, as expected in a climate change scenario, do not necessarily lead to a reduction in carbon export.

  2. Evaluation of fatty acids as biomarkers for a natural plankton community. A field study of a spring bloom and a post-bloom period off West Greenland

    DEFF Research Database (Denmark)

    Reuss, N.; Poulsen, Louise K.

    2002-01-01

    community were taken at the depth of fluorescence maximum. High biomass and diatom dominance during the spring bloom and low biomass and flagellate dominance in the post-bloom period were reflected by the fatty acid profiles. The total amount of fatty acid ranged from 55 to 132 mug 1(-1) during the spring...

  3. Comparative proteomic analysis of Listeria monocytogenes exposed to enterocin AS-48 in planktonic and sessile states.

    Science.gov (United States)

    Caballero Gómez, Natacha; Abriouel, Hikmate; Ennahar, Said; Gálvez, Antonio

    2013-10-15

    Enterocin AS-48 is a cyclic peptide of great interest for application in food preservation and sanitation. In the present study, the proteome response of Listeria monocytogenes to purified enterocin AS-48 was studied under two different conditions: planktonic cells and sessile cells grown on polystyrene plates. Ten different proteins were differentially expressed in planktonic L. monocytogenes cells treated with 0.1 μg/ml enterocin AS-48 compared to the untreated controls. Overexpressed proteins were related to stress response (DnaK) or carbohydrate transport and metabolism, while underexpressed and unexpressed proteins were related to metabolism (such as glyceraldehyde-3-phosphate dehydrogenase, pyruvate oxidase, glutamate dehydrogenase or glutamate decarboxylase) or stress (GroEL). In the sessile state, L. monocytogenes cells tolerated up to 10 μg/ml bacteriocin, and the treated biofilm cells overexpressed a set of 11 proteins, some of which could be related to stress response (DnaK, GroEL), protein synthesis and carbohydrate metabolism, while glyceraldehyde-3-phosphate dehydrogenase was the only unexpressed protein. Some of the overexpressed proteins (such as elongation factor Tu and GroEL) could also be implicated in cell adhesion. These results suggest different cell responses of L. monocytogenes to enterocin AS-48 in the planktonic and in the sessile state, including stress response and cell metabolism proteins. While in the planktonic state the bacterium may tend to compensate for the cytoplasmic cell permeability changes induced by AS-48 by reinforcing carbohydrate transport and metabolism, sessile cells seem to respond by shifting carbohydrate metabolism and reinforcing protein synthesis. Stress response proteins also seem to be important in the response to AS-48, but the stress response seems to be different in planktonic and in sessile cells. © 2013.

  4. Harmful algal blooms (HABs), dissolved organic matter (DOM), and planktonic microbial community dynamics at a near-shore and a harbour station influenced by upwelling (SW Iberian Peninsula)

    Science.gov (United States)

    Loureiro, Sofia; Reñé, Albert; Garcés, Esther; Camp, Jordi; Vaqué, Dolors

    2011-05-01

    The surface microalgal community, including harmful species, dissolved organic matter (DOM), and bacterial and viral populations were studied during an annual cycle (November 2007-October 2008) in a Near-shore (NS) and a Harbour (H) station located in an upwelling area (Sagres, SW Iberian Peninsula). The higher water residence time, water stability and shallowness of harbours in comparison with open waters likely contributed to the differences found between stations regarding chemical variables, statistical correlations and harmful algal proliferations. Also, several differences were noticed from a previous assessment ( Loureiro et al., 2005) including higher SST, lower nitrate and chlorophyll a concentrations, along with a shift in the microplankton community structure from diatom to nanoflagellate predominance. These variations feasibly reflect the response of this dynamic system to regional environmental modifications contributing to the understanding of common patterns in environmental change trends. The division of the sampling period into (1) non-upwelling (Non-Uw), (2) "spin-up" of upwelling (SU-Uw), and (3) "spin-down" and relaxation-downwelling (SD-Rel) stages allowed the identification of natural groupings of microplankton samples by Multi Dimensional Scaling (MDS) analysis. Dissolved organic nitrogen (DON) and viruses were the most significant abiotic and biotic variables, respectively, contributing to the dissimilarities between these stages (SIMPER analysis) and, therefore, potentially affecting the microplankton community structure. Harmful algal species and a stable viral community appeared to be favoured by SD-Rel conditions. Data seem to indicate that both Gymnodinium catenatum and Heterosigma akashiwo, the most abundant potentially harmful species, have been imported into the sampling area. Also, the H location, together with potential retention sites developing around the Cabo de São Vicente upwelling centre, may contribute to the local

  5. Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean

    Science.gov (United States)

    Trull, T. W.; Davies, D. M.; Dehairs, F.; Cavagna, A.-J.; Lasbleiz, M.; Laurenceau-Cornec, E. C.; d'Ovidio, F.; Planchon, F.; Leblanc, K.; Quéguiner, B.; Blain, S.

    2015-02-01

    We examined phytoplankton community responses to natural iron fertilisation at 32 sites over and downstream from the Kerguelen Plateau in the Southern Ocean during the austral spring bloom in October-November 2011. The community structure was estimated from chemical and isotopic measurements (particulate organic carbon - POC; 13C-POC; particulate nitrogen - PN; 15N-PN; and biogenic silica - BSi) on size-fractionated samples from surface waters (300, 210, 50, 20, 5, and 1 μm fractions). Higher values of 13C-POC (vs. co-located 13C values for dissolved inorganic carbon - DIC) were taken as indicative of faster growth rates and higher values of 15N-PN (vs. co-located 15N-NO3 source values) as indicative of greater nitrate use (rather than ammonium use, i.e. higher f ratios). Community responses varied in relation to both regional circulation and the advance of the bloom. Iron-fertilised waters over the plateau developed dominance by very large diatoms (50-210 μm) with high BSi / POC ratios, high growth rates, and significant ammonium recycling (lower f ratios) as biomass built up. In contrast, downstream polar frontal waters with a similar or higher iron supply were dominated by smaller diatoms (20-50 μm) and exhibited greater ammonium recycling. Stations in a deep-water bathymetrically trapped recirculation south of the polar front with lower iron levels showed the large-cell dominance observed on the plateau but much less biomass. Comparison of these communities to surface water nitrate (and silicate) depletions as a proxy for export shows that the low-biomass recirculation feature had exported similar amounts of nitrogen to the high-biomass blooms over the plateau and north of the polar front. This suggests that early spring trophodynamic and export responses differed between regions with persistent low levels vs. intermittent high levels of iron fertilisation.

  6. Planktonic foraminifera-derived environmental DNA extracted from abyssal sediments preserves patterns of plankton macroecology

    Directory of Open Access Journals (Sweden)

    R. Morard

    2017-06-01

    Full Text Available Deep-sea sediments constitute a unique archive of ocean change, fueled by a permanent rain of mineral and organic remains from the surface ocean. Until now, paleo-ecological analyses of this archive have been mostly based on information from taxa leaving fossils. In theory, environmental DNA (eDNA in the sediment has the potential to provide information on non-fossilized taxa, allowing more comprehensive interpretations of the fossil record. Yet, the process controlling the transport and deposition of eDNA onto the sediment and the extent to which it preserves the features of past oceanic biota remains unknown. Planktonic foraminifera are the ideal taxa to allow an assessment of the eDNA signal modification during deposition because their fossils are well preserved in the sediment and their morphological taxonomy is documented by DNA barcodes. Specifically, we re-analyze foraminiferal-specific metabarcodes from 31 deep-sea sediment samples, which were shown to contain a small fraction of sequences from planktonic foraminifera. We confirm that the largest portion of the metabarcode originates from benthic bottom-dwelling foraminifera, representing the in situ community, but a small portion (< 10 % of the metabarcodes can be unambiguously assigned to planktonic taxa. These organisms live exclusively in the surface ocean and the recovered barcodes thus represent an allochthonous component deposited with the rain of organic remains from the surface ocean. We take advantage of the planktonic foraminifera portion of the metabarcodes to establish to what extent the structure of the surface ocean biota is preserved in sedimentary eDNA. We show that planktonic foraminifera DNA is preserved in a range of marine sediment types, the composition of the recovered eDNA metabarcode is replicable and that both the similarity structure and the diversity pattern are preserved. Our results suggest that sedimentary eDNA could preserve the ecological structure of

  7. [Interdependence of plankton spatial distribution and plancton biomass temporal oscillations: mathematical simulation].

    Science.gov (United States)

    Medvedinskiĭ, A B; Tikhonova, I A; Li, B L; Malchow, H

    2003-01-01

    The dynamics of aquatic biological communities in a patchy environment is of great interest in respect to interrelations between phenomena at various spatial and time scales. To study the complex plankton dynamics in relation to variations of such a biologically essential parameter as the fish predation rate, we use a simple reaction-diffusion model of trophic interactions between phytoplankton, zooplankton, and fish. We suggest that plankton is distributed between two habitats one of which is fish-free due to hydrological inhomogeneity, while the other is fish-populated. We show that temporal variations in the fish predation rate do not violate the strong correspondence between the character of spatial distribution of plankton and changes of plankton biomass in time: regular temporal oscillations of plankton biomass correspond to large-scale plankton patches, while chaotic oscillations correspond to small-scale plankton patterns. As in the case of the constant fish predation rate, the chaotic plankton dynamics is characterized by coexistence of the chaotic attractor and limit cycle.

  8. Simulated Sampling of Estuary Plankton

    Science.gov (United States)

    Fortner, Rosanne W.; Jenkins, Deborah Bainer

    2009-01-01

    To find out about the microscopic life in the valuable estuary environment, it is usually necessary to be near the water. This dry lab offers an alternative, using authentic data and a simulation of plankton sampling. From the types of organisms found in the sample, middle school students can infer relationships in the biological and physical…

  9. High temporal and spatial diversity in marine RNA viruses implies that they have an important role in mortality and structuring plankton communities

    Directory of Open Access Journals (Sweden)

    Julia Anne Gustavsen

    2014-12-01

    Full Text Available Viruses in the order Picornavirales infect eukaryotes, and are widely distributed in coastal waters. Amplicon deep-sequencing of the RNA dependent RNA polymerase (RdRp revealed diverse and highly uneven communities of picorna-like viruses in the coastal waters of British Columbia (B.C., Canada. Almost 300 000 pyrosequence reads revealed 145 operational taxonomic units (OTUs based on 95% sequence similarity at the amino-acid level. Each sample had between 24 and 71 OTUs and there was little overlap among samples. Phylogenetic analysis revealed that some clades of OTUs were only found at one site; whereas, other groups included OTUs from all sites. Since most of these OTUs are likely from viruses that infect eukaryotic phytoplankton, and viral isolates infecting phytoplankton are strain-specific; each OTU probably arose from the lysis of a specific phytoplankton taxon. Moreover, the patchiness in OTU distribution, and the high turnover of viruses in the mixed layer, implies continuous infection and lysis by RNA viruses of a diverse array of eukaryotic phytoplankton taxa. Hence, these viruses are likely important elements structuring the phytoplankton community, and play a significant role in nutrient cycling and energy transfer.

  10. Plankton as an indicator of the temporal variation of the Chernobyl fallout

    International Nuclear Information System (INIS)

    Ravera, O.; Giannoni, L.

    1995-01-01

    Here we describe the pattern of radionuclide activities (iodine-131; cesium-134; cesium-137; ruthenium-106) in net-plankton and water samples collected from two lakes in Northern Italy (Lake Monate and Lake Comabbio) during and after the presence in the area of the radioactive cloud from the Chernobyl accident: from 30 April to 3 September 1986. The results show that, because of its short lifespan, plankton is a good indicator of daily variations of environmental contamination. The contamination level of plankton depends on various factors, such as the speciation and biological role of the radionuclide, the community structure and chemical characteristics of the water

  11. Trophic strategies of unicellular plankton

    DEFF Research Database (Denmark)

    Chakraborty, Subhendu; Nielsen, Lasse Tor; Andersen, Ken Haste

    2017-01-01

    . To this end, we develop and calibrate a trait-based model for unicellular planktonic organisms characterized by four traits: cell size and investments in phototrophy, nutrient uptake, and phagotrophy. We use the model to predict how optimal trophic strategies depend on cell size under various environmental...... unicellulars are colimited by organic carbon and nutrients, and only large photoautotrophs and smaller mixotrophs are nutrient limited; (2) trophic strategy is bottom-up selected by the environment, while optimal size is top-down selected by predation. The focus on cell size and trophic strategies facilitates......Unicellular plankton employ trophic strategies ranging from pure photoautotrophs over mixotrophy to obligate heterotrophs (phagotrophs), with cell sizes from 10-8 to 1 μg C. A full understanding of how trophic strategy and cell size depend on resource environment and predation is lacking...

  12. Mixotrophy in the marine plankton

    DEFF Research Database (Denmark)

    Stoecker, Diane K.; Hansen, Per Juel; Caron, David

    2017-01-01

    Mixotrophs are important components of the bacterioplankton, phytoplankton, microzooplankton, and (sometimes) zooplankton in coastal and oceanic waters. Bacterivory among the phytoplankton may be important for alleviating inorganic nutrient stress and may increase primary production in oligotrophic...... waters. Mixotrophic phytoflagellates and dinoflagellates are often dominant components of the plankton during seasonal stratification. Many of the microzooplankton grazers, including ciliates and Rhizaria, are mixotrophic owing to their retention of functional algal organelles or maintenance of algal...

  13. Plankton Dynamics and Mesoscale Turbulence

    Science.gov (United States)

    2010-06-29

    transformation of inorganic materials and light into living matter by photosynthesis) is operated mainly by small, unicellular algae that float freely in the...Aquatic ecosystems are characterized by the essential role played by fluid dynamics. The small organisms which compose the plankton are advected by the...surrounding flow and must cope with environmental currents, turbulence, and waves. And those organisms which anchor themselves to the rocks and to the

  14. Plankton networks driving carbon export in the oligotrophic ocean

    Science.gov (United States)

    Larhlimi, Abdelhalim; Roux, Simon; Darzi, Youssef; Audic, Stephane; Berline, Léo; Brum, Jennifer; Coelho, Luis Pedro; Espinoza, Julio Cesar Ignacio; Malviya, Shruti; Sunagawa, Shinichi; Dimier, Céline; Kandels-Lewis, Stefanie; Picheral, Marc; Poulain, Julie; Searson, Sarah; Stemmann, Lars; Not, Fabrice; Hingamp, Pascal; Speich, Sabrina; Follows, Mick; Karp-Boss, Lee; Boss, Emmanuel; Ogata, Hiroyuki; Pesant, Stephane; Weissenbach, Jean; Wincker, Patrick; Acinas, Silvia G.; Bork, Peer; de Vargas, Colomban; Iudicone, Daniele; Sullivan, Matthew B.; Raes, Jeroen; Karsenti, Eric; Bowler, Chris; Gorsky, Gabriel

    2015-01-01

    The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis, exported through sinking particles, and finally sequestered in the deep ocean. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure driving the process remains largely uncharacterised. Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve our understanding of carbon export in the oligotrophic ocean. We show that specific plankton communities, from the surface and deep chlorophyll maximum, correlate with carbon export at 150 m and highlight unexpected taxa such as Radiolaria, alveolate parasites, as well as Synechococcus and their phages, as lineages most strongly associated with carbon export in the subtropical, nutrient-depleted, oligotrophic ocean. Additionally, we show that the relative abundance of just a few bacterial and viral genes can predict most of the variability in carbon export in these regions. PMID:26863193

  15. Plankton networks driving carbon export in the oligotrophic ocean

    Science.gov (United States)

    2016-04-01

    The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis, exported through sinking particles, and finally sequestered in the deep ocean. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure driving the process remains largely uncharacterized. Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve our understanding of carbon export in the oligotrophic ocean. We show that specific plankton communities, from the surface and deep chlorophyll maximum, correlate with carbon export at 150 m and highlight unexpected taxa such as Radiolaria and alveolate parasites, as well as Synechococcus and their phages, as lineages most strongly associated with carbon export in the subtropical, nutrient-depleted, oligotrophic ocean. Additionally, we show that the relative abundance of a few bacterial and viral genes can predict a significant fraction of the variability in carbon export in these regions.

  16. Understanding Carbohydrates

    Science.gov (United States)

    ... Recipe Kits Delivered We've teamed up with Chef'd to bring you healthy recipe kits. Ways ... Us Policies Corporate Support Newsroom Press Releases For Professionals En Español Online Community Walk Bike Shop Sign ...

  17. Carbohydrate Counting

    Science.gov (United States)

    ... Rights Employment Discrimination Health Care Professionals Law Enforcement Driver's License For Lawyers Food & Fitness Home Food MyFoodAdvisor ... Fit Types of Activity Weight Loss Assess Your Lifestyle Getting Started Food Choices In My Community Home ...

  18. Microbial community stratification linked to utilization of carbohydrates and phosphorus limitation in a boreal peatland at Marcell Experimental Forest, Minnesota, USA.

    Science.gov (United States)

    Lin, Xueju; Tfaily, Malak M; Steinweg, J Megan; Chanton, Patrick; Esson, Kaitlin; Yang, Zamin K; Chanton, Jeffrey P; Cooper, William; Schadt, Christopher W; Kostka, Joel E

    2014-06-01

    This study investigated the abundance, distribution, and composition of microbial communities at the watershed scale in a boreal peatland within the Marcell Experimental Forest (MEF), Minnesota, USA. Through a close coupling of next-generation sequencing, biogeochemistry, and advanced analytical chemistry, a biogeochemical hot spot was revealed in the mesotelm (30- to 50-cm depth) as a pronounced shift in microbial community composition in parallel with elevated peat decomposition. The relative abundance of Acidobacteria and the Syntrophobacteraceae, including known hydrocarbon-utilizing genera, was positively correlated with carbohydrate and organic acid content, showing a maximum in the mesotelm. The abundance of Archaea (primarily crenarchaeal groups 1.1c and 1.3) increased with depth, reaching up to 60% of total small-subunit (SSU) rRNA gene sequences in the deep peat below the 75-cm depth. Stable isotope geochemistry and potential rates of methane production paralleled vertical changes in methanogen community composition to indicate a predominance of acetoclastic methanogenesis mediated by the Methanosarcinales in the mesotelm, while hydrogen-utilizing methanogens predominated in the deeper catotelm. RNA-derived pyrosequence libraries corroborated DNA sequence data to indicate that the above-mentioned microbial groups are metabolically active in the mid-depth zone. Fungi showed a maximum in rRNA gene abundance above the 30-cm depth, which comprised only an average of 0.1% of total bacterial and archaeal rRNA gene abundance, indicating prokaryotic dominance. Ratios of C to P enzyme activities approached 0.5 at the acrotelm and catotelm, indicating phosphorus limitation. In contrast, P limitation pressure appeared to be relieved in the mesotelm, likely due to P solubilization by microbial production of organic acids and C-P lyases. Based on path analysis and the modeling of community spatial turnover, we hypothesize that P limitation outweighs N limitation at

  19. Seasonal dynamics of plankton communities coupled with ...

    African Journals Online (AJOL)

    In this study, we studied the influence of the physical-chemical and biological factors (bacterioplankton and phytoplankton abundances) for zooplankton dynamics in a Sidi Saâd reservoir in Centre of Tunisia. The samplings were carried out in spring, summer, autumn and winter (2005 to 2006) in the deepest station (surface ...

  20. Changes in Microbial Plankton Assemblages Induced by Mesoscale Oceanographic Features in the Northern Gulf of Mexico.

    Directory of Open Access Journals (Sweden)

    Alicia K Williams

    Full Text Available Mesoscale circulation generated by the Loop Current in the Northern Gulf of Mexico (NGOM delivers growth-limiting nutrients to the microbial plankton of the euphotic zone. Consequences of physicochemically driven community shifts on higher order consumers and subsequent impacts on the biological carbon pump remain poorly understood. This study evaluates microbial plankton <10 μm abundance and community structure across both cyclonic and anti-cyclonic circulation features in the NGOM using flow cytometry (SYBR Green I and autofluorescence parameters. Non-parametric multivariate hierarchical cluster analyses indicated that significant spatial variability in community structure exists such that stations that clustered together were defined as having a specific 'microbial signature' (i.e. statistically homogeneous community structure profiles based on relative abundance of microbial groups. Salinity and a combination of sea surface height anomaly and sea surface temperature were determined by distance based linear modeling to be abiotic predictor variables significantly correlated to changes in microbial signatures. Correlations between increased microbial abundance and availability of nitrogen suggest nitrogen-limitation of microbial plankton in this open ocean area. Regions of combined coastal water entrainment and mesoscale convergence corresponded to increased heterotrophic prokaryote abundance relative to autotrophic plankton. The results provide an initial assessment of how mesoscale circulation potentially influences microbial plankton abundance and community structure in the NGOM.

  1. Plankton composition and biomass development

    DEFF Research Database (Denmark)

    Jakobsen, H.H.; Jepsen, P.M.; Blanda, E.

    2016-01-01

    Plankton food web dynamics were studied during a complete production season in a semi-intensive land-based facility for rearing of turbot (Scophthalmus maximus) larvae. The production season was divided into three production cycles of 3–5 weeks. Phytoplankton biomass (using chlorophyll a as biomass...... proxy) peaked in each production cycle. However, the maximum biomass decreased from spring (18 μg chlorophyll a L−1) to fall (ca. 7 μg chlorophyll a L−1), simultaneous with a decline in the concentration of dissolved nitrogen in the inoculating water. During the three production cycles, we observed...

  2. Hydromechanical signals in the plankton

    DEFF Research Database (Denmark)

    Visser, Andre

    2001-01-01

    The distance at which plankters can detect and thus interact with each other depends on their sensitivity, size, and motion, as well as the hydrodynamic characteristics of their behaviour. Through a simple consideration of the distribution of forces exerted on the ambient fluid by different...... proportional to a(3)Ur(-3). Within this context, observed planktonic interactions, particularly for copepods, were analysed and showed reasonably good support for the theory. The remote detection of inert particles by feeding-current-generating and free-swimming copepods was found to be feasible for known...... swimming ciliates under turbulent conditions showed good agreement with previously reported observations....

  3. Ecological-network models link diversity, structure and function in the plankton food-web

    Science.gov (United States)

    D'Alelio, Domenico; Libralato, Simone; Wyatt, Timothy; Ribera D'Alcalà, Maurizio

    2016-02-01

    A planktonic food-web model including sixty-three functional nodes (representing auto- mixo- and heterotrophs) was developed to integrate most trophic diversity present in the plankton. The model was implemented in two variants - which we named ‘green’ and ‘blue’ - characterized by opposite amounts of phytoplankton biomass and representing, respectively, bloom and non-bloom states of the system. Taxonomically disaggregated food-webs described herein allowed to shed light on how components of the plankton community changed their trophic behavior in the two different conditions, and modified the overall functioning of the plankton food web. The green and blue food-webs showed distinct organizations in terms of trophic roles of the nodes and carbon fluxes between them. Such re-organization stemmed from switches in selective grazing by both metazoan and protozoan consumers. Switches in food-web structure resulted in relatively small differences in the efficiency of material transfer towards higher trophic levels. For instance, from green to blue states, a seven-fold decrease in phytoplankton biomass translated into only a two-fold decrease in potential planktivorous fish biomass. By linking diversity, structure and function in the plankton food-web, we discuss the role of internal mechanisms, relying on species-specific functionalities, in driving the ‘adaptive’ responses of plankton communities to perturbations.

  4. De scheiding van slib en plankton

    NARCIS (Netherlands)

    Budding, M.C.

    1974-01-01

    It is possible to separate non-living suspended matter and living plankton with the help of a common laboratory centrifuge and a commercial silica-gel called LUDOX. With this method it becomes possible to determine particle size of suspended matter and plankton separately with e.g. a Coulter

  5. Carbohydrates Through Animation: Preliminary Step

    Directory of Open Access Journals (Sweden)

    J.K. Sugai

    2004-05-01

    Full Text Available Methods of education are changing, so the educational tools must change too. The developmentof the systems of information and communication gave the opportunity to bring new technology tothe learning process. Modern education needs interactive programs that may be available to theacademic community, in order to ease the learning process and sharing of the knowledge. Then,an educational software on Carbohydrates is being developed using concept maps and FLASH-MXanimations program, and approached through six modules. The introduction of Carbohydrates wasmade by the module Carbohydrates on Nature, which shows the animations gures of a teacher andstudents, visiting a farm, identifying the carbohydrates found in vegetables, animals, and microor-ganisms, integrated by links containing short texts to help understanding the structure and functionof carbohydrates. This module was presented, as pilot experiment, to teachers and students, whichdemonstrated satisfaction, and high receptivity, by using animation and interactivitys program asstrategy to biochemistrys education. The present work is part of the project Biochemistry throughanimation, which is having continuity.

  6. The effects of the Sea Empress oil spill on the plankton of the Southern Irish Sea

    International Nuclear Information System (INIS)

    Batten, S.D.; Allen, R.J.S.; Wotton, C.O.M.

    1998-01-01

    This study investigates the effects of the Sea Empress oil spill on the local plankton communities which are an important component of the marine ecosystem. The Continuous Plankton Recorder survey has monitored the plankton in this area since 1970 giving an extensive time series for comparison with post-spill samples. The analytical procedures applied and results obtained are presented and reveal that, with some exceptions, no significant effects were evident. Barnacle larvae were not recorded post-spill and the spring zooplankton community was somewhat different to the previous year. A long-term trend is apparent in the community but the most common taxa showed no significant changes, suggesting a minor shift in species composition rather than a dramatic change. (author)

  7. Carbohydrate-Loading Diet

    Science.gov (United States)

    ... Grape juice (12 ounces) 55 225 Lunch Milk, chocolate, reduced fat (12 ounces) 45 285 4 slices ... usual during carbohydrate loading to get the same benefits as a man does. Despite carbohydrate loading, you ...

  8. Carbohydrate Metabolism Disorders

    Science.gov (United States)

    ... metabolic disorder, something goes wrong with this process. Carbohydrate metabolism disorders are a group of metabolic disorders. Normally your enzymes break carbohydrates down into glucose (a type of sugar). If ...

  9. Carbohydrates in Supramolecular Chemistry.

    Science.gov (United States)

    Delbianco, Martina; Bharate, Priya; Varela-Aramburu, Silvia; Seeberger, Peter H

    2016-02-24

    Carbohydrates are involved in a variety of biological processes. The ability of sugars to form a large number of hydrogen bonds has made them important components for supramolecular chemistry. We discuss recent advances in the use of carbohydrates in supramolecular chemistry and reveal that carbohydrates are useful building blocks for the stabilization of complex architectures. Systems are presented according to the scaffold that supports the glyco-conjugate: organic macrocycles, dendrimers, nanomaterials, and polymers are considered. Glyco-conjugates can form host-guest complexes, and can self-assemble by using carbohydrate-carbohydrate interactions and other weak interactions such as π-π interactions. Finally, complex supramolecular architectures based on carbohydrate-protein interactions are discussed.

  10. Plankton bloom controlled by horizontal stirring

    Science.gov (United States)

    McKiver, W.; Neufeld, Z.; Scheuring, I.

    2009-10-01

    Here we show a simple mechanism in which changes in the rate of horizontal stirring by mesoscale ocean eddies can trigger or suppress plankton blooms and can lead to an abrupt change in the average plankton density. We consider a single species phytoplankton model with logistic growth, grazing and a spatially non-uniform carrying capacity. The local dynamics have multiple steady states for some values of the carrying capacity that can lead to localized blooms as fluid moves across the regions with different properties. We show that for this model even small changes in the ratio of biological timescales relative to the flow timescales can greatly enhance or reduce the global plankton productivity. Thus, this may be a possible mechanism in which changes in horizontal mixing can trigger plankton blooms or cause regime shifts in some oceanic regions. Comparison between the spatially distributed model and Lagrangian simulations considering temporal fluctuations along fluid trajectories, demonstrates that small scale transport processes also play an important role in the development of plankton blooms with a significant influence on global biomass.

  11. Surface ocean metabarcoding confirms limited diversity in planktonic foraminifera but reveals unknown hyper-abundant lineages.

    Science.gov (United States)

    Morard, Raphaël; Garet-Delmas, Marie-José; Mahé, Frédéric; Romac, Sarah; Poulain, Julie; Kucera, Michal; de Vargas, Colomban

    2018-02-07

    Since the advent of DNA metabarcoding surveys, the planktonic realm is considered a treasure trove of diversity, inhabited by a small number of abundant taxa, and a hugely diverse and taxonomically uncharacterized consortium of rare species. Here we assess if the apparent underestimation of plankton diversity applies universally. We target planktonic foraminifera, a group of protists whose known morphological diversity is limited, taxonomically resolved and linked to ribosomal DNA barcodes. We generated a pyrosequencing dataset of ~100,000 partial 18S rRNA foraminiferal sequences from 32 size fractioned photic-zone plankton samples collected at 8 stations in the Indian and Atlantic Oceans during the Tara Oceans expedition (2009-2012). We identified 69 genetic types belonging to 41 morphotaxa in our metabarcoding dataset. The diversity saturated at local and regional scale as well as in the three size fractions and the two depths sampled indicating that the diversity of foraminifera is modest and finite. The large majority of the newly discovered lineages occur in the small size fraction, neglected by classical taxonomy. These unknown lineages dominate the bulk [>0.8 µm] size fraction, implying that a considerable part of the planktonic foraminifera community biomass has its origin in unknown lineages.

  12. A resource-based game theoretical approach for the paradox of the plankton

    Directory of Open Access Journals (Sweden)

    Weini Huang

    2016-08-01

    Full Text Available The maintenance of species diversity is a central focus in ecology. It is not rare to observe more species than the number of limiting resources, especially in plankton communities. However, such high species diversity is hard to achieve in theory under the competitive exclusion principles, known as the plankton paradox. Previous studies often focus on the coexistence of predefined species and ignore the fact that species can evolve. We model multi-resource competitions using evolutionary games, where the number of species fluctuates under extinction and the appearance of new species. The interspecific and intraspecific competitions are captured by a dynamical payoff matrix, which has a size of the number of species. The competition strength (payoff entries is obtained from comparing the capability of species in consuming resources, which can change over time. This allows for the robust coexistence of a large number of species, providing a possible solution to the plankton paradox.

  13. A resource-based game theoretical approach for the paradox of the plankton.

    Science.gov (United States)

    Huang, Weini; de Araujo Campos, Paulo Roberto; Moraes de Oliveira, Viviane; Fagundes Ferrreira, Fernando

    2016-01-01

    The maintenance of species diversity is a central focus in ecology. It is not rare to observe more species than the number of limiting resources, especially in plankton communities. However, such high species diversity is hard to achieve in theory under the competitive exclusion principles, known as the plankton paradox. Previous studies often focus on the coexistence of predefined species and ignore the fact that species can evolve. We model multi-resource competitions using evolutionary games, where the number of species fluctuates under extinction and the appearance of new species. The interspecific and intraspecific competitions are captured by a dynamical payoff matrix, which has a size of the number of species. The competition strength (payoff entries) is obtained from comparing the capability of species in consuming resources, which can change over time. This allows for the robust coexistence of a large number of species, providing a possible solution to the plankton paradox.

  14. Neutral carbohydrate geochemistry of particulate material in the central equatorial Pacific

    Science.gov (United States)

    Hernes, Peter J.; Hedges, John I.; Peterson, Michael L.; Wakeham, Stuart G.; Lee, Cindy

    Neutral carbohydrate compositions were determined for particulate samples from plankton net tows, shallow floating sediment traps, mid-depth and deep moored sediment traps, and sediment cores collected along a north-south transect in the central equatorial Pacific Ocean during the U.S. JGOFS EqPac program. Total neutral carbohydrate depth profiles and patterns along the transect follow essentially the same trends as bulk and organic carbon (OC) fluxes—attenuating with depth, high near the equator and decreasing poleward. OC-normalized total aldose (TCH 2,O) yields along the transect and with depth do not show any consitent patterns. Relative to a planktonic source, neutral carbohydrate compositions in sediment trap and sediment core samples reflect preferential loss of ribose and storage carbohydrates rich in glucose, and preferential preservation of structural carbohydrates rich in rhamnose, xylose, fucose, and mannose. There is also evidence for an intermediately labile component rich in galactose. It appears that compositional signatures of neutral carbohydrates in sediments are more dependent upon their planktonic source than on any particular diagenetic pathway. Relative to other types of organic matter, neutral carbohydrates are better preserved in calcareous oozes from 12°S to 5°N than in red clays at 9°N based on OC-normalized TCH 2O yields, due to either differing sources or sorption characteristics. Weight per cent glucose generally decreases with increased degradation of organic material in the central equatorial Pacific region. Based on weight per cent glucose, comparisons of samples between Survey I (El Niõn) and Survey II (non-El Niño) indicate that during Survey I, organic material in the epipelagic zone in the northern hemisphere may have undergone more degradation than organic material in the southern hemisphere.

  15. Carbohydrates and Diabetes (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Carbohydrates and Diabetes KidsHealth / For Parents / Carbohydrates and Diabetes ... many kids with diabetes take to stay healthy. Carbohydrates and Blood Sugar The two main forms of ...

  16. SEAMAP 2015 Fall Plankton Survey (PC1504, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During the 2015 Fall Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

  17. SEAMAP 2013 Fall Plankton Survey (PC1305, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During the 2013 Fall Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

  18. SEAMAP Fall 2014 Plankton Survey (GU1405, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During the 2014 Fall Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

  19. SEAMAP 2013 Fall Plankton Survey (PC1305, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During the 2013 Fall Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

  20. SEAMAP Spring 2016 Plankton Survey (R21601, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During the 2016 Spring Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

  1. SEAMAP Spring 2015 Plankton Survey (GU1501, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During the 2015 Spring Plankton Survey, plankton samples were collected from a systematic grid of stations to assess distribution, occurrence and abundance of the...

  2. How well does the Continuous Plankton Recorder (CPR) sample zooplankton? A comparison with the Longhurst Hardy Plankton Recorder (LHPR) in the northeast Atlantic

    Science.gov (United States)

    Richardson, Anthony J.; John, Eurgain H.; Irigoien, Xabier; Harris, Roger P.; Hays, Graeme C.

    2004-09-01

    The Continuous Plankton Recorder (CPR) survey has collected data on basin-scale zooplankton abundance in the North Atlantic since the 1930s. These data have been used in many studies to elucidate seasonal patterns and long-term change in plankton populations, as well as more recently to validate ecosystem models. There has, however, been relatively little comparison of the data from the CPR with that from other samplers. In this study we compare zooplankton abundance estimated from the CPR in the northeast Atlantic with near-surface samples collected by a Longhurst-Hardy Plankton Recorder (LHPR) at Ocean Weather Station India (59°N, 19°W) between 1971 and 1975. Comparisons were made for six common copepods in the region: Acartia clausi, Calanus finmarchicus, Euchaeta norvegica, Metridia lucens, Oithona sp., and Pleuromamma robusta. Seasonal cycles based on CPR data were similar to those recorded by the LHPR. Differences in absolute abundances were apparent, however, with the CPR underestimating abundances by a factor of between 5 and 40, with the exception of A. clausi. Active avoidance by zooplankton is thought to be responsible. This avoidance is species specific, so that care must be taken describing communities, as the CPR emphasises those species that are preferentially caught, a problem common to many plankton samplers.

  3. Continuous daylight in the high-Arctic summer supports high plankton respiration rates compared to those supported in the dark

    KAUST Repository

    Mesa, Elena

    2017-04-21

    Plankton respiration rate is a major component of global CO2 production and is forecasted to increase rapidly in the Arctic with warming. Yet, existing assessments in the Arctic evaluated plankton respiration in the dark. Evidence that plankton respiration may be stimulated in the light is particularly relevant for the high Arctic where plankton communities experience continuous daylight in spring and summer. Here we demonstrate that plankton community respiration evaluated under the continuous daylight conditions present in situ, tends to be higher than that evaluated in the dark. The ratio between community respiration measured in the light (Rlight) and in the dark (Rdark) increased as the 2/3 power of Rlight so that the Rlight:Rdark ratio increased from an average value of 1.37 at the median Rlight measured here (3.62 µmol O2 L-1 d-1) to an average value of 17.56 at the highest Rlight measured here (15.8 µmol O2 L-1 d-1). The role of respiratory processes as a source of CO2 in the Arctic has, therefore, been underestimated and is far more important than previously believed, particularly in the late spring, with 24 h photoperiods, when community respiration rates are highest.

  4. Factors affecting egg ratios in planktonic rotifers

    NARCIS (Netherlands)

    Sarma, S.S.S.; Gulati, R.D.; Nandini, S.

    2005-01-01

    Edmondson’s egg ratio (number of amictic eggs per female) is an important life history variable, which has been in wide use to understand and predict patterns of population growth in planktonic rotifers under field conditions. It is also useful as an indicator of the health of rotifers under culture

  5. Modelling emergent trophic strategies in plankton

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Aksnes, Dag L.; Berge, Terje

    2015-01-01

    Plankton are typically divided into phytoplankton and zooplankton in marine ecosystem models. Yet, most protists in the photic zone engage in some degree of phagotrophy, and it has been suggested that trophic strategy is really a continuum between pure phototrophs (phytoplankton) and pure...

  6. Biofilms and planktonic cells of Deinococcus geothermalis in extreme environments

    Science.gov (United States)

    Panitz, Corinna; Reitz, Guenther; Rabbow, Elke; Rettberg, Petra; Flemming, Hans-Curt; Wingender, Jost; Froesler, Jan

    In addition to the several extreme environments on Earth, Space can be considered as just another exceptional environment with a unique mixture of stress factors comprising UV radiation, vacuum, desiccation, temperature, ionizing radiation and microgravity. Life that processes in these environments can depend on the life forms and their state of living. The question is whether there are different strategies for individual microorganisms compared to communities of the same organisms to cope with the different factors of their surroundings. Comparative studies of the survi-val of these communities called biofilms and planktonic cell samples of Deinococcus geothermalis stand at the focal point of the presented investigations. A biofilm is a structured community of microorganisms that live encapsulated in a matrix of extracellular polymeric substances on a surface. Microorganisms living in a biofilm usually have significantly different properties to cooperate than individually living microorganisms of the same species. An advantage of the biofilm is increased resistance to various chemical and physical effects, while the dense extracellular matrix and the outer layer of the cells protect the interior of the microbial consortium. The space experiment BOSS (Biofilm organisms surfing Space) as part the ESA experimental unit EXPOSE R-2 with a planned launch date in July 2014 will be subsequently mounted on the Russian Svesda module outside the ISS. An international team of scientists coordinated by Dr. P. Rettberg will investigate the hypothesis whether microorganisms organized as biofilm outmatch the same microorganisms exposed individually in the long-term survival of the harsh environmental conditions as they occur in space and on Mars. Another protective function in the samples could be dust par-ticles for instance Mars regolith simulant contained inside the biofilms or mixed with the planktonic cells, as additional shelter especially against the extraterrestrial UV

  7. CARBOHYDRATE-CONTAINING COMPOUNDS WHICH BIND TO CARBOHYDRATE BINDING RECEPTORS

    DEFF Research Database (Denmark)

    1995-01-01

    Carbohydrate-containing compounds which contain saccharides or derivatives thereof and which bind to carbohydrate binding receptors are useful in pharmaceutical products for treatment of inflammatory diseases and other diseases.......Carbohydrate-containing compounds which contain saccharides or derivatives thereof and which bind to carbohydrate binding receptors are useful in pharmaceutical products for treatment of inflammatory diseases and other diseases....

  8. Mercury methylation rates of biofilm and plankton microorganisms from a hydroelectric reservoir in French Guiana.

    Science.gov (United States)

    Huguet, L; Castelle, S; Schäfer, J; Blanc, G; Maury-Brachet, R; Reynouard, C; Jorand, F

    2010-02-15

    The Petit-Saut ecosystem is a hydroelectric reservoir covering 365km(2) of flooded tropical forest. This reservoir and the Sinnamary Estuary downstream of the dam are subject to significant mercury methylation. The mercury methylation potential of plankton and biofilm microorganisms/components from different depths in the anoxic reservoir water column and from two different sites along the estuary was assessed. For this, reservoir water and samples of epiphytic biofilms from the trunk of a submerged tree in the anoxic water column and from submerged branches in the estuary were batch-incubated from 1h to 3 months with a nominal 1000ng/L spike of Hg(II) chloride enriched in (199)Hg. Methylation rates were determined for different reservoir and estuarine communities under natural nutrient (reservoir water, estuary freshwater) and artificial nutrient (culture medium) conditions. Methylation rates in reservoir water incubations were the highest with plankton microorganisms sampled at -9.5m depth (0.5%/d) without addition of biofilm components. Mercury methylation rates of incubated biofilm components were strongly enhanced by nutrient addition. The results suggested that plankton microorganisms strongly contribute to the total Hg methylation in the Petit-Saut reservoir and in the Sinnamary Estuary. Moreover, specific methylation efficiencies (%Me(199)Hg(net)/cell) suggested that plankton microorganisms could be more efficient methylating actors than biofilm consortia and that their methylation efficiency may be reduced in the presence of biofilm components. Extrapolation to the reservoir scale of the experimentally determined preliminary methylation efficiencies suggested that plankton microorganisms in the anoxic water column could produce up to 27mol MeHg/year. Taking into account that (i) demethylation probably occurs in the reservoir and (ii) that the presence of biofilm components may limit the methylation efficiency of plankton microorganisms, this result is

  9. Carbohydrates and Depression.

    Science.gov (United States)

    Wurtman, Richard J.; Wurtman, Judith J.

    1989-01-01

    Describes the symptoms, such as appetite change and mood fluctuation, basic mechanisms, and some treatments of Seasonal Affective Disorder (SAD), Carbohydrate-Craving Obesity (CCO) and Premenstrual Syndrome (PMS). Provides several tables and diagrams, and three reading references. (YP)

  10. Millennial-scale plankton regime shifts in the subtropical North Pacific Ocean.

    Science.gov (United States)

    McMahon, Kelton W; McCarthy, Matthew D; Sherwood, Owen A; Larsen, Thomas; Guilderson, Thomas P

    2015-12-18

    Climate change is predicted to alter marine phytoplankton communities and affect productivity, biogeochemistry, and the efficacy of the biological pump. We reconstructed high-resolution records of changing plankton community composition in the North Pacific Ocean over the past millennium. Amino acid-specific δ(13)C records preserved in long-lived deep-sea corals revealed three major plankton regimes corresponding to Northern Hemisphere climate periods. Non-dinitrogen-fixing cyanobacteria dominated during the Medieval Climate Anomaly (950-1250 Common Era) before giving way to a new regime in which eukaryotic microalgae contributed nearly half of all export production during the Little Ice Age (~1400-1850 Common Era). The third regime, unprecedented in the past millennium, began in the industrial era and is characterized by increasing production by dinitrogen-fixing cyanobacteria. This picoplankton community shift may provide a negative feedback to rising atmospheric carbon dioxide concentrations. Copyright © 2015, American Association for the Advancement of Science.

  11. Toxicity of waters from the Rochester Embayment Area of Concern to the plankton species Pseudokirchneriella subcapitata and Ceriodaphnia dubia

    Science.gov (United States)

    Baldigo, Barry P.; Duffy, Brian T.; Smith, Alexander J.; George, Scott D.

    2016-01-01

    The lower Genesee River and Rochester Embayment of Lake Ontario are a designated Area of Concern (AOC) under the binational Great Lakes Water Quality Agreement. The “degradation of phytoplankton and zooplankton populations” or plankton Beneficial Use Impairment (BUI) was classified as unknown and in need of further assessment in this AOC because water quality data suggested plankton communities could be effected and community data were either unavailable or indicated impacts. The plankton BUI may now be obsolete because local contaminant sources have been largely eliminated. The present study was conducted between July 2013 and August 2014 to assess the BUI-removal criteria: “AOC plankton bioassays confirm that toxicity in ambient waters (i.e., no growth inhibition) is not significantly higher than comparable non-AOC controls”. Acute and chronic toxicity of waters from 13 sites were quantified seasonally using standardized bioassays with the green alga Pseudokirchneriella subcapitata and water flea Ceriodaphnia dubia to test the hypothesis that toxicity of waters from AOC sites was not higher than that of waters from comparable non-AOC reference sites. Survival and reproduction of C. dubia did not differ significantly between site types, systems, or months. The growth of P. subcapitata did not differ between site types, but differed among systems and months. All results indicate that waters from AOC sites were no more toxic to both plankton species than waters from reference sites. Assuming test species represent natural plankton assemblages, water quality should not negatively affect survival and growth of resident plankton populations in the Rochester Embayment AOC.

  12. Estimating planktonic diversity through spatial dominance patterns in a model ocean.

    Science.gov (United States)

    Soccodato, Alice; d'Ovidio, Francesco; Lévy, Marina; Jahn, Oliver; Follows, Michael J; De Monte, Silvia

    2016-10-01

    In the open ocean, the observation and quantification of biodiversity patterns is challenging. Marine ecosystems are indeed largely composed by microbial planktonic communities whose niches are affected by highly dynamical physico-chemical conditions, and whose observation requires advanced methods for morphological and molecular classification. Optical remote sensing offers an appealing complement to these in-situ techniques. Global-scale coverage at high spatiotemporal resolution is however achieved at the cost of restrained information on the local assemblage. Here, we use a coupled physical and ecological model ocean simulation to explore one possible metrics for comparing measures performed on such different scales. We show that a large part of the local diversity of the virtual plankton ecosystem - corresponding to what accessible by genomic methods - can be inferred from crude, but spatially extended, information - as conveyed by remote sensing. Shannon diversity of the local community is indeed highly correlated to a 'seascape' index, which quantifies the surrounding spatial heterogeneity of the most abundant functional group. The error implied in drastically reducing the resolution of the plankton community is shown to be smaller in frontal regions as well as in regions of intermediate turbulent energy. On the spatial scale of hundreds of kms, patterns of virtual plankton diversity are thus largely sustained by mixing communities that occupy adjacent niches. We provide a proof of principle that in the open ocean information on spatial variability of communities can compensate for limited local knowledge, suggesting the possibility of integrating in-situ and satellite observations to monitor biodiversity distribution at the global scale. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

    Directory of Open Access Journals (Sweden)

    Lara S. eGarcia-Corral

    2015-07-01

    Full Text Available The Mediterranean Sea is a vulnerable region for climate change, warming at higher rates compare to the global ocean. Warming leads to increased stratification of the water column and enhanced the oligotrophic nature of the Mediterranean Sea. The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely enhancing impacts to biota.Here we experimentally elucidate the cumulative effects of warming and natural UV-B radiation on the net community production (NCP of plankton communities. We conducted five experiments at monthly intervals, from June to October 2013, and evaluated the responses of NCP to ambient UV-B radiation and warming (+3ºC, alone and in combination, in a coastal area of the northwest Mediterranean Sea. UV-B radiation and warming lead to reduced net community production and resulted in a heterotrophic (NCP<0 metabolic balance. Both UV-B radiation and temperature, showed a significant individual effect in NCP across treatments and time. However, their joint effect showed to be synergistic as the interaction between them (UV x Temp was statistically significant in most of the experiments performed. Our results showed that both drivers, would affect the gas exchange of CO2-O2 from and to the atmosphere and the role of plankton communities in the Mediterranean carbon cycle

  14. Research highlights: impacts of microplastics on plankton.

    Science.gov (United States)

    Lin, Vivian S

    2016-02-01

    Each year, millions of metric tons of the plastic produced for food packaging, personal care products, fishing gear, and other human activities end up in lakes, rivers, and the ocean. The breakdown of these primary plastics in the environment results in microplastics, small fragments of plastic typically less than 1-5 mm in size. These synthetic particles have been detected in all of the world's oceans and also in many freshwater systems, accumulating in sediment, on shorelines, suspended in surface waters, and being ingested by plankton, fish, birds, and marine mammals. While the occurrence of plastics in surface waters has been surveyed in a number of studies, the impacts of microplastics on marine organisms are still being elucidated. This highlight features three recent publications that explore the interactions of microplastics with planktonic organisms to clarify the effects of these pollutants on some of the ocean's smallest and most important inhabitants.

  15. TOF-SIMS characterization of planktonic foraminifera

    International Nuclear Information System (INIS)

    Vering, G.; Crone, C.; Bijma, J.; Arlinghaus, H.F.

    2003-01-01

    Oceanic sediment properties that are closely related to former environmental (e.g. climatic) parameters are called 'proxies'. Planktonic foraminifera are small protists which make up part of the plankton. Certain element concentrations, element ratios and isotopic ratios of their calcite shell found in the sediment can be used as proxies reflecting the state of the ocean during the life of the animal; they supply useful information for the reconstruction of environmental parameters. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to examine the inner and outer part of foraminiferal shells, as well as foraminiferal shells dissolved in HCl. High resolution elemental images and mass spectra were obtained from the foraminifera. The data show that TOF-SIMS is a useful technique for determining the elemental distribution and for measuring isotope ratios such as δ 11 B with high precision in a single foraminiferal shell

  16. TOF-SIMS characterization of planktonic foraminifera

    Energy Technology Data Exchange (ETDEWEB)

    Vering, G.; Crone, C.; Bijma, J.; Arlinghaus, H.F

    2003-01-15

    Oceanic sediment properties that are closely related to former environmental (e.g. climatic) parameters are called 'proxies'. Planktonic foraminifera are small protists which make up part of the plankton. Certain element concentrations, element ratios and isotopic ratios of their calcite shell found in the sediment can be used as proxies reflecting the state of the ocean during the life of the animal; they supply useful information for the reconstruction of environmental parameters. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to examine the inner and outer part of foraminiferal shells, as well as foraminiferal shells dissolved in HCl. High resolution elemental images and mass spectra were obtained from the foraminifera. The data show that TOF-SIMS is a useful technique for determining the elemental distribution and for measuring isotope ratios such as {delta}{sup 11}B with high precision in a single foraminiferal shell.

  17. Plankton Assemblage Estimated with BGC-Argo Floats in the Southern Ocean: Implications for Seasonal Successions and Particle Export

    Science.gov (United States)

    Rembauville, Mathieu; Briggs, Nathan; Ardyna, Mathieu; Uitz, Julia; Catala, Philippe; Penkerc'h, Cristophe; Poteau, Antoine; Claustre, Hervé; Blain, Stéphane

    2017-10-01

    The Southern Ocean (SO) hosts plankton communities that impact the biogeochemical cycles of the global ocean. However, weather conditions in the SO restrict mainly in situ observations of plankton communities to spring and summer, preventing the description of biological successions at an annual scale. Here, we use shipboard observations collected in the Indian sector of the SO to develop a multivariate relationship between physical and bio-optical data, and, the composition and carbon content of the plankton community. Then we apply this multivariate relationship to five biogeochemical Argo (BGC-Argo) floats deployed within the same bio-geographical zone as the ship-board observations to describe spatial and seasonal changes in plankton assemblage. The floats reveal a high contribution of bacteria below the mixed layer, an overall low abundance of picoplankton and a seasonal succession from nano- to microplankton during the spring bloom. Both naturally iron-fertilized waters downstream of the Crozet and Kerguelen Plateaus show elevated phytoplankton biomass in spring and summer but they differ by a nano- or microplankton dominance at Crozet and Kerguelen, respectively. The estimated plankton group successions appear consistent with independent estimations of particle diameter based on the optical signals. Furthermore, the comparison of the plankton community composition in the surface layer with the presence of large mesopelagic particles diagnosed by spikes of optical signals provides insight into the nature and temporal changes of ecological vectors that drive particle export. This study emphasizes the power of BGC-Argo floats for investigating important biogeochemical processes at high temporal and spatial resolution.

  18. Effects of solar ultraviolet radiation (UVR) on molecular diversity of plankton from the Chubut rivers estuary

    International Nuclear Information System (INIS)

    Manrique, J.M.; Halac, S.; Calvo, A.Y.; Villafane, V.; Jones, L.R.; Helbling, W.E.

    2010-01-01

    Within the framework of a project designed to evaluate the impact of UVR upon estuarine plankton, we present here a molecular analysis of plankton diversity. Water samples were exposed to three radiation treatments (PAR, PAR + UV-A and PAR + UV-A + UV-B) in microcosms for ca 10 days during the Austral summer. At the beginning (t 0 ) and at the end of the experiment samples were filtered 0 through 20, 10, 5 and 0.22 μm pore sizes. The DNA amount retained in each filter indicated that most of the plankton biomass was in the 0.22-5 μm fraction at t0. In contrast, at the end of the experiment this proportion changed according to the radiation treatment and big cells (> 20 μm) dominated. An rDNA library was obtained from the DNA corresponding to the 0.22-5 μm fraction. There was no relationship between treatments and the number and frequency of restriction genotypes. Analyses of 27 clones fraction from t 0 indicated the presence of three genera of Rhodobacteraceae, one genus of Rhodospirillaceae, one SAR11 genus, one genus of Bacillaceae, an unclassified sequences of Alphaproteobacteria, Actinobacteria and Rhodospirillaceae. Also, there were six sequences similar to Ostreococcus tauri (Mamiellales). Even though the sequence analyses are still ongoing, our initial data suggest a big impact of UV-B radiation in the amount and composition of the plankton community towards big cells. (authors)

  19. Computer vision for continuous plankton monitoring

    OpenAIRE

    Damian Janusz Matuszewski

    2014-01-01

    Plankton microorganisms constitute the base of the marine food web and play a great role in global atmospheric carbon dioxide drawdown. Moreover, being very sensitive to any environmental changes they allow noticing (and potentially counteracting) them faster than with any other means. As such they not only influence the fishery industry but are also frequently used to analyze changes in exploited coastal areas and the influence of these interferences on local environment and climate. As a co...

  20. Who is the carbohydrate?

    Directory of Open Access Journals (Sweden)

    Paulo Enrique Cuevas Mestanza

    2017-10-01

    Full Text Available Biochemistry is a complex science that studies biomolecules and their interactions in metabolic pathways in living beings. Due to the large amount of contents against the short period to apply them, only expositive classes are not enough to arouse the interest of students and solve questions. In this perspective, is very important to develop new educational tools to improve the understanding of these contents. “Who is the carbohydrate?” It is a didactic game created to review the structural and functional relationship of carbohydrates. Based on the classic “Guess who?” The objective of the player or group is to first find out the opponent's carbohydrate name.

  1. Nutrient supply, surface currents, and plankton dynamics predict zooplankton hotspots in coastal upwelling systems

    Science.gov (United States)

    Messié, Monique; Chavez, Francisco P.

    2017-09-01

    A simple combination of wind-driven nutrient upwelling, surface currents, and plankton growth/grazing equations generates zooplankton patchiness and hotspots in coastal upwelling regions. Starting with an initial input of nitrate from coastal upwelling, growth and grazing equations evolve phytoplankton and zooplankton over time and space following surface currents. The model simulates the transition from coastal (large phytoplankton, e.g., diatoms) to offshore (picophytoplankton and microzooplankton) communities, and in between generates a large zooplankton maximum. The method was applied to four major upwelling systems (California, Peru, Northwest Africa, and Benguela) using latitudinal estimates of wind-driven nitrate supply and satellite-based surface currents. The resulting zooplankton simulations are patchy in nature; areas of high concentrations coincide with previously documented copepod and krill hotspots. The exercise highlights the importance of the upwelling process and surface currents in shaping plankton communities.

  2. Standard filtration practices may significantly distort planktonic microbial diversity estimates

    Directory of Open Access Journals (Sweden)

    Cory Cruz Padilla

    2015-06-01

    Full Text Available Fractionation of biomass by filtration is a standard method for sampling planktonic microbes. It is unclear how the taxonomic composition of filtered biomass changes depending on sample volume. Using seawater from a marine oxygen minimum zone, we quantified the 16S rRNA gene composition of biomass on a prefilter (1.6 μm pore-size and a downstream 0.2 μm filter over sample volumes from 0.05 to 5 L. Significant community shifts occurred in both filter fractions, and were most dramatic in the prefilter community. Sequences matching Vibrionales decreased from ~40-60% of prefilter datasets at low volumes (0.05-0.5 L to less than 5% at higher volumes, while groups such at the Chromatiales and Thiohalorhabdales followed opposite trends, increasing from minor representation to become the dominant taxa at higher volumes. Groups often associated with marine particles, including members of the Deltaproteobacteria, Planctomycetes and Bacteroidetes, were among those showing the greatest increase with volume (4 to 27-fold. Taxon richness (97% similarity clusters also varied significantly with volume, and in opposing directions depending on filter fraction, highlighting potential biases in community complexity estimates. These data raise concerns for studies using filter fractionation for quantitative comparisons of aquatic microbial diversity, for example between free-living and particle-associated communities.

  3. Kelimpahan dan Keanekaragaman Plankton di Perairan Selat Bali (Plankton Abundance and Diversity in the Bali Strait

    Directory of Open Access Journals (Sweden)

    Ruly Isfatul Khasanah

    2013-12-01

    Full Text Available Fitoplankton mempunyai peran sangat penting dalam suatu perairan, selain berada pada dasar rantai makanan sedangkan zooplankton merupakan herbivor pemangsanya. Penelitian mengenai kelimpahan dan keanekaragaman plankton di perairan Selat Bali dilakukan pada musim peralihan II (Nopember 2012 dan musim barat (Pebruari 2013. Penelitian bertujuan untuk mengamati perbedaan kelimpahan dan keanekaragaman plankton pada dua musim angin muson. Sampel air diambil dengan menggunakan water sampler sedangkan sampel plankton diambil secara horisontal dan vertikal  pada kedalaman 1 m dan 20 m dengan jaring plankton Kitahara bermata jaring 20 µm. Hasil pengukuran nutrien pada musim peralihan II memiliki kadar fosfat, nitrat, bahan organik, silikat dan klorofil-a lebih tinggi dibandingkan pada musim barat. Informasi tersebut memperkuat indikasi adanya perpindahan massa air dari lapisan yang lebih dalam ke lapisan yang lebih dangkal. Nutrien fosfat dan nitrat diperlukan untuk mempertahankan fungsi membran sel dan silikia dibutuhkan untuk pembentukan dinding sel terutama pada diatom. Hasil penelitian juga menunjukkan bahwa kelas diatom (Bacillariophyceae mencapai 95,9 % dari total jenis dan kelimpahan fitoplankton seluruh stasiun penelitian, sisanya berasal dari genus Dinophyceae. Kelimpahan fitoplankton tertinggi terjadi pada musim peralihan II dengan Rhizosolenia stolterfothii sebesar 51.405 sel.L-1 (80,1%, sedangkan pada musim barat copepoda ditemukan melimpah sebesar 8.178 ind.L-1 (88,3 %. Hasil ini mengindikasikan bahwa dengan kelimpahan plankton yang ditemukan perairan Selat Bali dinilai cukup potensial untuk mendukung kehidupan biota laut pelagis. Kata kunci: plankton, selat Bali, rhizosolenia stolterfothii, muson   Abstract Phytoplankton has important role as primary producer in the sea and act as base of food chain while zooplankton act as herbivore prey on them. Research on abundance and diversity of plankton at Bali Strait was performed during

  4. Identification of Carbohydrate Metabolism Genes in the Metagenome of a Marine Biofilm Community Shown to Be Dominated by Gammaproteobacteria and Bacteroidetes

    Directory of Open Access Journals (Sweden)

    Jennifer L. Edwards

    2010-10-01

    Full Text Available Polysaccharides are an important source of organic carbon in the marine environment and degradation of the insoluble and globally abundant cellulose is a major component of the marine carbon cycle. Although a number of species of cultured bacteria are known to degrade crystalline cellulose, little is known of the polysaccharide hydrolases expressed by cellulose-degrading microbial communities, particularly in the marine environment. Next generation 454 Pyrosequencing was applied to analyze the microbial community that colonizes and degrades insoluble polysaccharides in situ in the Irish Sea. The bioinformatics tool MG-RAST was used to examine the randomly sampled data for taxonomic markers and functional genes, and showed that the community was dominated by members of the Gammaproteobacteria and Bacteroidetes. Furthermore, the identification of 211 gene sequences matched to a custom-made database comprising the members of nine glycoside hydrolase families revealed an extensive repertoire of functional genes predicted to be involved in cellulose utilization. This demonstrates that the use of an in situ cellulose baiting method yielded a marine microbial metagenome considerably enriched in functional genes involved in polysaccharide degradation. The research reported here is the first designed to specifically address the bacterial communities that colonize and degrade cellulose in the marine environment and to evaluate the glycoside hydrolase (cellulase and chitinase gene repertoire of that community, in the absence of the biases associated with PCR-based molecular techniques.

  5. Planktonic Crustacean Culture - Live Planktonic Crustaceans as Live Feed for Finfish and Shrimps in Aquaculture

    DEFF Research Database (Denmark)

    Jepsen, Per Meyer; Syberg, Kristian; Drillet, Guillaume

    2018-01-01

    The cultivation of planktonic crustaceans as live feed is of paramount importance for the aquaculture and aquarium industries. The use of live cladocerans as feed for freshwater fish is limited to the aquarium industry, whereas Artemia and copepods are used to feed edible marine fish larvae...... assessments for hazardous chemicals. Cladocerans are widely used for ecotoxicology testing but Artemia and copepods are emerging new model species. In the present chapter, we review the culturing procedures of these important planktonic crustaceans: Artemia, cladocerans and copepods and discuss their use...

  6. Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

    KAUST Repository

    Garcia-Corral, Lara S.

    2015-07-07

    The Mediterranean Sea is a vulnerable region for climate change, warming at higher rates compare to the global ocean. Warming leads to increased stratification of the water column and enhanced the oligotrophic nature of the Mediterranean Sea. The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A) may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely enhancing impacts to biota. Here we experimentally elucidate the cumulative effects of warming and natural UV-B radiation on the net community production (NCP) of plankton communities. We conducted five experiments at monthly intervals, from June to October 2013, and evaluated the responses of NCP to ambient UV-B radiation and warming (+3°C), alone and in combination, in a coastal area of the northwest Mediterranean Sea. UV-B radiation and warming lead to reduced NCP and resulted in a heterotrophic (NCP < 0) metabolic balance. Both UV-B radiation and temperature, showed a significant individual effect in NCP across treatments and time. However, their joint effect showed to be synergistic as the interaction between them (UV × Temp) was statistically significant in most of the experiments performed. Our results showed that both drivers, would affect the gas exchange of CO2−O2 from and to the atmosphere and the role of plankton communities in the Mediterranean carbon cycle.

  7. DINAMIKA KOMUNITAS PLANKTON DI PERAIRAN EKOSISTEM HUTAN BAKAU SEGARA ANAKAN YANG SEDANG BERUBAH (Plankton Dynamic in the Changing Mangrove Ecosystem of Segara Anakan Central Java

    Directory of Open Access Journals (Sweden)

    Tjut Sugandawaty Djohan

    2010-11-01

    Full Text Available ABSTRAK Perairan hutan bakau Segara Anakan merupakan ekosistem yang sedang berubah karena sedimentasi yang tinggi sejak tahun 1980, dan telah mengakibatkan pendangkalan perainan dan mengganggu proses pasang surut. Perubahan ekosistem ini direspon oleh komunitas plankton. pada musim hujan tabun 2002 salinitas perairannya adalah 0 0/00' dan musim kemarau 20 – 32%. Perubahan komunitas plankton tersebut dicirikan hadimya komunitas baik phyto maupun zooplankton dominan sungai pada musim hujan, dan sebaliknya komunitas laut pada musim kemarau. Pada tahun 2004, karena pendangkalan di perairan Bondan, mudflat dan perairannya dikeruk. Penelitian ini bertujuan untuk mempelajari respon komunitas phyto dan zooplankton terhadap pernbanan ekosistem pada musim kemarau Agustus 2005 di daerah tangkapan ikan nelayan perairan Segara Anakan. Hasil menunjukkan bahwa ada peledakan kemelimpahan phytoplankton yang didommasi olehl populasi Chaetoceros di perairan Bondan dan Klaces sebanyak 206890 dan 397273 individu per 100 liter, dan populasi  Asterione/lajaponica meningkat sebanyak 69778 per 100 liter di perairan Cigatal. Peledakan kedua genus tersebut adalah merupakan respon phytoplankton terhadap meningkatnya kandungan PO4 di perairan oleh pengerukan sedimen di perairan Bondan. Kenaikan P04 di perairan berturut-berturut dari Bondan ke Cigatal sebesar 4,95 ppm, 5,88 ppm, dan 4,62 ppm. Pada musim kemarau, perairan Segara Anakan juga dicirikan dengan hadimya komunitas plankton sungai yaitu sebanyak 19 species phytoplankton, dan 9 spesies zooplankton. Peledakan populasi Chaetoceros tidak direspon oleh peledakan populasi zooplankton. Keadaan ini mencerminkan bahwa kualitas perairan Segara Anakan telah menurun.   ABSTRACT The mangrove ecosystem of Segara Anakan is in the process of changing to the freshwater-wetland due to the heavy sedimentation. This change was responded by the plankton communities. In the 2002 during the rainy season, the salinity

  8. Carbohydrate intake and obesity

    NARCIS (Netherlands)

    van Dam, R M; Seidell, J C

    2007-01-01

    The prevalence of obesity has increased rapidly worldwide and the importance of considering the role of diet in the prevention and treatment of obesity is widely acknowledged. This paper reviews data on the effects of dietary carbohydrates on body fatness. Does the composition of the diet as related

  9. Biofilm and planktonic pneumococci demonstrate disparate immunoreactivity to human convalescent sera

    Directory of Open Access Journals (Sweden)

    Shivshankar Pooja

    2011-11-01

    Full Text Available Abstract Background Streptococcus pneumoniae (the pneumococcus is the leading cause of otitis media, community-acquired pneumonia (CAP, sepsis, and meningitis. It is now evident that S. pneumoniae forms biofilms during nasopharyngeal colonization; the former which facilitates persistence, the latter, a prerequisite for subsequent development of invasive disease. Proteomic evaluation of S. pneumoniae suggests the antigen profile available for host-recognition is altered as a consequence of biofilm growth. This has potentially meaningful implications in regards to adaptive immunity and protection from disseminated disease. We therefore examined the antigen profile of biofilm and planktonic pneumococcal cell lysates, tested their reactivity with human convalescent sera and that generated against biofilm pneumococci, and examined whether immunization with biofilm pneumococci protected mice against infectious challenge. Results Biofilm pneumococci have dramatically altered protein profiles versus their planktonic counterparts. During invasive disease the humoral immune response is skewed towards the planktonic protein profile. Immunization with biofilm bacteria does not elicit a strong-cross-reactive humoral response against planktonic bacteria nor confer resistance against challenge with a virulent isolate from another serotype. We identified numerous proteins, including Pneumococcal serine-rich repeat protein (PsrP, which may serve as a protective antigens against both colonization and invasive disease. Conclusion Differential protein production by planktonic and biofilm pneumococci provides a potential explanation for why individuals remain susceptible to invasive disease despite previous colonization events. These findings also strongly suggest that differential protein production during colonization and disease be considered during the selection of antigens for any future protein vaccine.

  10. COPEPOD: The Coastal & Oceanic Plankton Ecology, Production, & Observation Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal & Oceanic Plankton Ecology, Production, & Observation Database (COPEPOD) provides NMFS scientists with quality-controlled, globally distributed...

  11. Spatio-temporal pattern formation, fractals, and chaos in conceptual ecological models as applied to coupled plankton-fish dynamics

    International Nuclear Information System (INIS)

    Medvinskii, Aleksandr B; Tikhonova, Irina A; Tikhonov, D A; Ivanitskii, Genrikh R; Petrovskii, Sergei V; Li, B.-L.; Venturino, E; Malchow, H

    2002-01-01

    The current turn-of-the-century period witnesses the intensive use of the bioproducts of the World Ocean while at the same time calling for precautions to preserve its ecological stability. This requires that biophysical processes in aquatic systems be comprehensively explored and new methods for monitoring their dynamics be developed. While aquatic and terrestrial ecosystems have much in common in terms of their mathematical description, there are essential differences between them. For example, the mobility of oceanic plankton is mainly controlled by diffusion processes, whereas terrestrial organisms naturally enough obey totally different laws. This paper is focused on the processes underlying the dynamics of spatially inhomogeneous plankton communities. We demonstrate that conceptual reaction-diffusion mathematical models are an appropriate tool for investigating both complex spatio-temporal plankton dynamics and the fractal properties of planktivorous fish school walks. (reviews of topical problems)

  12. Different effects of planktonic invertebrate predators and fish on the plankton community in experimental mesocosms

    Czech Academy of Sciences Publication Activity Database

    Šorf, M.; Brandl, Z.; Znachor, Petr; Vašek, Mojmír

    2014-01-01

    Roč. 50, č. 1 (2014), s. 71-83 ISSN 0003-4088 Institutional support: RVO:60077344 Keywords : predation * zooplankton * perch * roach * mesocosms Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.042, year: 2014

  13. Plankton motility patterns and encounter rates

    DEFF Research Database (Denmark)

    Visser, Andre; Kiørboe, Thomas

    2006-01-01

    measure of run length to reaction distance determines whether the underlying encounter is ballistic or diffusive. Since ballistic interactions are intrinsically more efficient than diffusive, we predict that organisms will display motility with long correlation run lengths compared to their reaction...... distances to their prey, but short compared to the reaction distances of their predators. We show motility data for planktonic organisms ranging from bacteria to copepods that support this prediction. We also present simple ballistic and diffusive motility models for estimating encounter rates, which lead...

  14. Viral to metazoan marine plankton nucleotide sequences from the Tara Oceans expedition.

    Science.gov (United States)

    Alberti, Adriana; Poulain, Julie; Engelen, Stefan; Labadie, Karine; Romac, Sarah; Ferrera, Isabel; Albini, Guillaume; Aury, Jean-Marc; Belser, Caroline; Bertrand, Alexis; Cruaud, Corinne; Da Silva, Corinne; Dossat, Carole; Gavory, Frédérick; Gas, Shahinaz; Guy, Julie; Haquelle, Maud; Jacoby, E'krame; Jaillon, Olivier; Lemainque, Arnaud; Pelletier, Eric; Samson, Gaëlle; Wessner, Mark; Acinas, Silvia G; Royo-Llonch, Marta; Cornejo-Castillo, Francisco M; Logares, Ramiro; Fernández-Gómez, Beatriz; Bowler, Chris; Cochrane, Guy; Amid, Clara; Hoopen, Petra Ten; De Vargas, Colomban; Grimsley, Nigel; Desgranges, Elodie; Kandels-Lewis, Stefanie; Ogata, Hiroyuki; Poulton, Nicole; Sieracki, Michael E; Stepanauskas, Ramunas; Sullivan, Matthew B; Brum, Jennifer R; Duhaime, Melissa B; Poulos, Bonnie T; Hurwitz, Bonnie L; Pesant, Stéphane; Karsenti, Eric; Wincker, Patrick

    2017-08-01

    A unique collection of oceanic samples was gathered by the Tara Oceans expeditions (2009-2013), targeting plankton organisms ranging from viruses to metazoans, and providing rich environmental context measurements. Thanks to recent advances in the field of genomics, extensive sequencing has been performed for a deep genomic analysis of this huge collection of samples. A strategy based on different approaches, such as metabarcoding, metagenomics, single-cell genomics and metatranscriptomics, has been chosen for analysis of size-fractionated plankton communities. Here, we provide detailed procedures applied for genomic data generation, from nucleic acids extraction to sequence production, and we describe registries of genomics datasets available at the European Nucleotide Archive (ENA, www.ebi.ac.uk/ena). The association of these metadata to the experimental procedures applied for their generation will help the scientific community to access these data and facilitate their analysis. This paper complements other efforts to provide a full description of experiments and open science resources generated from the Tara Oceans project, further extending their value for the study of the world's planktonic ecosystems.

  15. Carbohydrates as Fat Replacers.

    Science.gov (United States)

    Peng, Xingyun; Yao, Yuan

    2017-02-28

    The overconsumption of dietary fat contributes to various chronic diseases, which encourages attempts to develop and consume low-fat foods. Simple fat reduction causes quality losses that impede the acceptance of foods. Fat replacers are utilized to minimize the quality deterioration after fat reduction or removal to achieve low-calorie, low-fat claims. In this review, the forms of fats and their functions in contributing to food textural and sensory qualities are discussed in various food systems. The connections between fat reduction and quality loss are described in order to clarify the rationales of fat replacement. Carbohydrate fat replacers usually have low calorie density and provide gelling, thickening, stabilizing, and other texture-modifying properties. In this review, carbohydrates, including starches, maltodextrins, polydextrose, gums, and fibers, are discussed with regard to their interactions with other components in foods as well as their performances as fat replacers in various systems.

  16. Developmental Stages of some Tropical and Subtropical Planktonic Marine Copepods

    NARCIS (Netherlands)

    Björnberg, Tagea K.S.

    1972-01-01

    Most planktonic marine copepods have nauplii which differ greatly from the copepodids so that it is difficult to relate them to the adult form. Rearing experiments are usually unsuccessful; only 8% of ca. 800 species of planktonic marine copepods have identified nauplii (see below cited list). To

  17. Epithelial cell detachment by Porphyromonas gingivalis biofilm and planktonic cultures

    NARCIS (Netherlands)

    Huang, L.; van Loveren, C.; Ling, J.; Wei, X.; Crielaard, W.; Deng, D.M.

    2016-01-01

    Porphyromonas gingivalis is present as a biofilm at the sites of periodontal infections. The detachment of gingival epithelial cells induced by P. gingivalis biofilms was examined using planktonic cultures as a comparison. Exponentially grown planktonic cultures or 40-h biofilms were co-incubated

  18. Larval and Juvenile Ascothoracida (Crustacea) from the Plankton

    OpenAIRE

    Grygier, Mark J.

    1988-01-01

    Two kinds of previously recorded ascothoracid larvae from plankton over coral reefs in Hawaii and the Virgin Islands are redescribed as possible representatives of the Lauridae and Petrarcidae, respectively. A bathyal, tropical Atlantic ascothoracid larva from an epibenthic sled sample cannot confidently be identified to family. A planktonic, juvenile ascothoracidan from the eastern Indian Ocean belongs to the genus Synagoga.

  19. Specialized activities and expression differences for Clostridium thermocellum biofilm and planktonic cells.

    Science.gov (United States)

    Dumitrache, Alexandru; Klingeman, Dawn M; Natzke, Jace; Rodriguez, Miguel; Giannone, Richard J; Hettich, Robert L; Davison, Brian H; Brown, Steven D

    2017-02-27

    Clostridium (Ruminiclostridium) thermocellum is a model organism for its ability to deconstruct plant biomass and convert the cellulose into ethanol. The bacterium forms biofilms adherent to lignocellulosic feedstocks in a continuous cell-monolayer in order to efficiently break down and uptake cellulose hydrolysates. We developed a novel bioreactor design to generate separate sessile and planktonic cell populations for omics studies. Sessile cells had significantly greater expression of genes involved in catabolism of carbohydrates by glycolysis and pyruvate fermentation, ATP generation by proton gradient, the anabolism of proteins and lipids and cellular functions critical for cell division consistent with substrate replete conditions. Planktonic cells had notably higher gene expression for flagellar motility and chemotaxis, cellulosomal cellulases and anchoring scaffoldins, and a range of stress induced homeostasis mechanisms such as oxidative stress protection by antioxidants and flavoprotein co-factors, methionine repair, Fe-S cluster assembly and repair in redox proteins, cell growth control through tRNA thiolation, recovery of damaged DNA by nucleotide excision repair and removal of terminal proteins by proteases. This study demonstrates that microbial attachment to cellulose substrate produces widespread gene expression changes for critical functions of this organism and provides physiological insights for two cells populations relevant for engineering of industrially-ready phenotypes.

  20. Assessing spatial and temporal variability of phytoplankton communities' composition in the Iroise Sea ecosystem (Brittany, France): A 3D modeling approach. Part 1: Biophysical control over plankton functional types succession and distribution

    Science.gov (United States)

    Cadier, Mathilde; Gorgues, Thomas; Sourisseau, Marc; Edwards, Christopher A.; Aumont, Olivier; Marié, Louis; Memery, Laurent

    2017-01-01

    Understanding the dynamic interplay between physical, biogeochemical and biological processes represents a key challenge in oceanography, particularly in shelf seas where complex hydrodynamics are likely to drive nutrient distribution and niche partitioning of phytoplankton communities. The Iroise Sea includes a tidal front called the 'Ushant Front' that undergoes a pronounced seasonal cycle, with a marked signal during the summer. These characteristics as well as relatively good observational sampling make it a region of choice to study processes impacting phytoplankton dynamics. This innovative modeling study employs a phytoplankton-diversity model, coupled to a regional circulation model to explore mechanisms that alter biogeography of phytoplankton in this highly dynamic environment. Phytoplankton assemblages are mainly influenced by the depth of the mixed layer on a seasonal time scale. Indeed, solar incident irradiance is a limiting resource for phototrophic growth and small phytoplankton cells are advantaged over larger cells. This phenomenon is particularly relevant when vertical mixing is intense, such as during winter and early spring. Relaxation of wind-induced mixing in April causes an improvement of irradiance experienced by cells across the whole study area. This leads, in late spring, to a competitive advantage of larger functional groups such as diatoms as long as the nutrient supply is sufficient. This dominance of large, fast-growing autotrophic cells is also maintained during summer in the productive tidally-mixed shelf waters. In the oligotrophic surface layer of the western part of the Iroise Sea, small cells coexist in a greater proportion with large, nutrient limited cells. The productive Ushant tidal front's region (1800 mgC·m- 2·d- 1 between August and September) is also characterized by a high degree of coexistence between three functional groups (diatoms, micro/nano-flagellates and small eukaryotes/cyanobacteria). Consistent with

  1. Protein and carbohydrate in P-POM collected from the fishing ground in Minnan-Taiwan Bank

    Science.gov (United States)

    Su, Yongquan; Zhang, Huan

    1992-06-01

    The analysis of the protein and carbohydrate in P-POM (Plankton and Particulate Organic Matter) samples collected from the fishing ground in Minnan-Taiwan Bank in five voyages (April, June, July, August and November, 1988) shows that the protein and carbohydrate contents and amounts in samples from four stations (501, 401, 301, 201) along the coast and another four stations (404, 304, 403, 204) south and southeast of the shoal were higher than those in April and November, indicating that this phenomenon is related to the upwelling in the two regions in summer.

  2. Effects of Carbohydrate Consumption Case Study: carbohydrates in Bread

    Directory of Open Access Journals (Sweden)

    Neacsu N.A.

    2014-12-01

    Full Text Available Carbohydrates perform numerous roles in living organisms; they are an important source of energy. The body uses carbohydrates to make glucose which is the fuel that gives it energy and helps keep everything going. However, excess carbohydrate consumption has negative health effects. Bread is a basic product in our nutrition and it also is a product with a high content of carbohydrates. So, it is important to find out more information on bread and on the recommended bread type best for consumption.

  3. Long-Term Trends and Temporal Synchrony in Plankton Richness, Diversity and Biomass Driven by Re-Oligotrophication and Climate across 17 Danish Lakes

    Directory of Open Access Journals (Sweden)

    Korhan Özkan

    2016-09-01

    Full Text Available A two-decade (1989–2008 time series of lake phyto- and zooplankton, water characteristics and climate in 17 Danish lakes was analysed to examine the long term changes and the effects of lake restoration efforts. The analyses of the pair-wise correlations across time series revealed a strong synchrony in climatic variables among the lakes. A significant, but weak increase in air temperature was observed and resulted in a corresponding increase in surface water temperature only in summer. Lake physico-chemical variables had weaker synchrony than climatic variables. Synchrony in water temperature and stratification was stronger than lake chemistry as the former is mostly affected by atmospheric energy flux. Synchrony in the taxonomic richness of the plankton groups and phytoplankton biomass was apparent, to a similar degree as observed for lake chemistry. The synchrony and the temporal trends in lake chemistry and plankton were more pronounced for the lakes with strong re-oligotrophication. Phytoplankton biomass decreased and plankton richness increased in these lakes, with a shift from Chlorophyta dominance towards more heterogeneous phytoplankton communities. Notably, a widespread significant positive trend in plankton richness was observed not only in lakes with strong re-oligotrophication but across all lakes. The widespread increase in plankton richness coincided with widespread decrease in phosphate and total nitrogen concentrations, as well as with the trends in climate indicating a likely joint effect of nutrient reduction and climate in driving lake plankton. However, temporal changes and synchrony as well as the recovery of richness and composition of lake plankton more coherently corresponded with the nutrient loading reduction across the Danish landscape, while the role of climate control of the lake plankton was less pronounced.

  4. The ecology of plankton in biological oceanography: a tribute to Marta Estrada’s task

    Directory of Open Access Journals (Sweden)

    Jordi Solé

    2016-09-01

    Full Text Available Plankton ecology has been the object of intense research and progress in the last few decades. This has been partly due to technological advances that have facilitated the multidisciplinary and high-resolution sampling of ecosystems and improved experimentation and analytical methodologies, and to sophisticated modelling. In addition, exceptional researchers have had the vision to integrate all these innovative tools to form a solid theoretical background in ecology. Here we provide an overview of the outstanding research work conducted by Professor Marta Estrada and her pioneering contribution to different areas of research in the last four decades. Her research in biological oceanography has mainly focussed on phytoplankton ecology, taxonomy and physiology, the functional structure of plankton communities, and physical and biological interactions in marine ecosystems. She has combined a variety of field and laboratory approaches and methodologies, from microscopy to satellite observations, including in-depth statistical data analysis and modelling. She has been a reference for scientists all over the world. Here, her contributions to plankton ecology are summarized by some of her students and closest collaborators, who had the privilege to share their science and everyday experiences with her.

  5. Spindle-shaped Microstructures: Potential Models for Planktonic Life Forms on Other Worlds

    Science.gov (United States)

    Oehler, Dorothy Z.; Walsh, Maud M.; Sugitani, Kenichiro; House, Christopher H.

    2014-01-01

    Spindle-shaped, organic microstructures ("spindles") are now known from Archean cherts in three localities (Figs. 1-4): The 3 Ga Farrel Quartzite from the Pilbara of Australia [1]; the older, 3.3-3.4 Ga Strelley Pool Formation, also from the Pilbara of Australia [2]; and the 3.4 Ga Kromberg Formation of the Barberton Mountain Land of South Africa [3]. Though the spindles were previously speculated to be pseudofossils or epigenetic organic contaminants, a growing body of data suggests that these structures are bona fide microfossils and further, that they are syngenetic with the Archean cherts in which they occur [1-2, 4-10]. As such, the spindles are among some of the oldest-known organically preserved microfossils on Earth. Moreover, recent delta C-13 study of individual spindles from the Farrel Quartzite (using Secondary Ion Mass Spectrometry [SIMS]) suggests that the spindles may have been planktonic (living in open water), as opposed to benthic (living as bottom dwellers in contact with muds or sediments) [9]. Since most Precambrian microbiotas have been described from benthic, matforming communities, a planktonic lifestyle for the spindles suggests that these structures could represent a segment of the Archean biosphere that is poorly known. Here we synthesize the recent work on the spindles, and we add new observations regarding their geographic distribution, robustness, planktonic habit, and long-lived success. We then discuss their potential evolutionary and astrobiological significance.

  6. Mercury speciation in plankton from the Cabo Frio Bay, SE--Brazil.

    Science.gov (United States)

    Silva-Filho, Emmanoel V; Kütter, Vinicius T; Figueiredo, Thiago S; Tessier, Emmanuel; Rezende, Carlos E; Teixeira, Daniel C; Silva, Carlos A; Donard, Olivier F X

    2014-12-01

    Mercury (Hg) is considered a global pollutant, and the scientific community has shown great concern about its toxicity as it may affect the biota of entire systems, through bioaccumulation and bioamplification processes of its organic form, methylmercury (MeHg), along food web. However, few research studies deal with bioaccumulation of Hg from marine primary producers and the first-order consumers. So, this study aims to determine Hg distribution and concentration levels in phytoplankton and zooplankton in the Cabo Frio Bay, Brazil, a site influenced by coastal upwelling. The results from Hg speciation analyses show that inorganic mercury Hg(II) was the predominant specie in plankton from this bay. The annual Hg species distribution in plankton shown mean concentration of 2.00 ± 1.28 ng Hg(II) g(-1) and 0.15 ± 0.08 ng MeHg g(-1) wet weight (phytoplankton) and 2.5 ± 2.03 ng Hg(II) g(-1) and 0.25 ± 0.09 ng MeHg g(-1) wet weight (zooplankton). Therefore, upwelling zones should be considered in the Hg biogeochemical cycle models as a process that enhances Hg(II) bioaccumulation in plankton, raising its bioavailability and shelf deposition.

  7. Issues in Nutrition: Carbohydrates.

    Science.gov (United States)

    Thompson, Margaret E; Noel, Mary Barth

    2017-01-01

    Carbohydrates include sugars, starches, and dietary fibers. Resistant starches resemble fiber in their behavior in the intestinal tract, and may have positive effects on blood glucose levels and the gut microbiome. Fibers are classified as soluble and insoluble, but most fiber-containing foods contain a mixture of soluble and insoluble fiber. Soluble fiber has been shown to lower low-density lipoprotein cholesterol levels. Many artificial sweeteners and other sugar substitutes are available. Most natural sources of sweeteners also are energy sources. Many artificial sweeteners contain no kilocalories in the amounts typically used. Sugar alcohols may have a laxative effect when consumed in large amounts. Glycemic index and glycemic load are measurements that help quantify serum glucose response after ingestion of particular foods. These measurements may be affected by the combination of foods consumed in a given meal, and the glycemic index may vary among individuals eating the same meal. Eating foods with a low glycemic index may help prevent development of type 2 diabetes. There is no definitive evidence to recommend low-carbohydrate diets over low-fat diets for long-term weight loss; they are equally effective. Written permission from the American Academy of Family Physicians is required for reproduction of this material in whole or in part in any form or medium.

  8. Consequences of Stinging Plankton Blooms on Finfish Mariculture in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Mar Bosch-Belmar

    2017-08-01

    Full Text Available In recent years, caged finfish mariculture across European seas suffered production losses by severe fish mortality, following episodic outbreaks of invertebrate cnidarian stingers. Due to their stinging cells and injectable venoms, medusozoan jellyfish, or drifting propagules of polyp colonies at high density may impair caged fish health through toxic effects on vulnerable tissues of gills and skin, and related secondary bacterial infections. Gill disorders in European sea bass (Dicentrarchus labrax fish farms along the Spanish Mediterranean coast are commonly reported, but regular monitoring of the frequency of cnidarian outbreaks and their potential impacts on caged fish is still poorly enforced. In this study, two sea bass mariculture farms in Southern Spain (Málaga; Almería were monitored biweekly for zooplankton, phytoplankton and fish gills condition, over 13 or 30 months for the Málaga and Almería facilities, respectively, within the period 2012–2014. Significant, direct correlations were found among low water temperature, recorded fish mortalities, and high abundances of planktonic cnidarians, particularly of the hydrozoan siphonophores Muggiaea atlantica and M. kochii, and the larval stage of Ectopleura larynx, a common member of cage biofouling communities. A significant relationship between cnidarian densities and the quantitative scoring of gill pathology was also observed. In addition, high densities of long-bristled planktonic diatoms (Chaetoceros spp. coincided with a major fish mortality event (April 2012, Almería farm. Standardised monitoring of plankton dynamics and composition may help in promoting response capacities of Mediterranean mariculture managers to fish health challenges (such as stinging plankton blooms by (a improving diagnostic tools and preventative countermeasures and (b supporting the development of science-based spatial planning and sustainable growth of coastal mariculture.

  9. Impact of Dietary Carbohydrate and Protein Levels on Carbohydrate Metabolism

    Science.gov (United States)

    Lasker, Denise Ann

    2009-01-01

    The goal of this dissertation was to investigate the impact of changing dietary carbohydrate (CARB) intakes within recommended dietary guidelines on metabolic outcomes specifically associated with glycemic regulations and carbohydrate metabolism. This research utilized both human and animal studies to examine changes in metabolism across a wide…

  10. Optical absorption of irradiated carbohydrates

    International Nuclear Information System (INIS)

    Supe, A.A.; Tiliks, Yu.E.

    1994-01-01

    The optical absorption spectra of γ-irradiated carbohydrates (glucose, lactose, sucrose, maltose, and starch) and their aqueous solutions were studied. The comparison of the data obtained with the determination of the concentrations of molecular and radical products of radiolysis allows the absorption bands with maxima at 250 and 310 nm to be assigned to the radicals trapped in the irradiated carbohydrates

  11. Recent planktonic foraminifera from the sediment off Karwar and Mangalore

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Guptha, M.V.S.

    Eleven samples collected from the shelf-slope regions off Karwar and mangalore transects of the Arabian Sea, yielded fifteen planktonic foraminiferal species, which are identified and described. There is a progressive increase in the percentage...

  12. GLOBEC NEP Vertical Plankton Tow (VPT) Data, 1997-2001

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GLOBEC (GLOBal Ocean ECosystems Dynamics) NEP (Northeast Pacific) California Current Program Vertical Plankton Tow (VPT) Data For more information, see...

  13. GLOBEC NEP MOCNESS Plankton (MOC1) Data, 2000-2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GLOBEC (GLOBal Ocean ECosystems Dynamics) NEP (Northeast Pacific) California Current Program MOCNESS Plankton (MOC1) Data The MOCNESS is based on the Tucker Trawl...

  14. Living planktonic foraminifera of the Wadge bank, Northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Panikkar, B.M.; Kutty, M.K.

    Twenty three species of living planktonic Foraminifera belonging to 11 genera have been studied from the Wadge Bank area off southern tip of the Indian peninsula. The fauna is characterized by species such as Globigerinoides conglobatus, G...

  15. Planktonic algae and cyanoprokaryotes as indicators of ecosystem ...

    African Journals Online (AJOL)

    Planktonic algae and cyanoprokaryotes as indicators of ecosystem quality in the Mooi River system in the North-West Province, South Africa. ... is important for maintaining the quality of potable water of Potchefstroom and surrounding areas.

  16. Bacteriophage-antibiotic synergism to control planktonic and biofilm ...

    African Journals Online (AJOL)

    Bacteriophage-antibiotic synergism to control planktonic and biofilm producing clinical isolates of Pseudomonas aeruginosa. Amina Amal Mahmoud Nouraldin, Manal Mohammad Baddour, Reem Abdel Hameed Harfoush, Sara AbdelAziz Mohamed Essa ...

  17. Partitioning of organic production in marine plankton communities

    DEFF Research Database (Denmark)

    Conan, P.; Søndergaard, Morten; Kragh, T.

    2007-01-01

    We investigated the partitioning of carbon, nitrogen, and phosphorus between particulate and dissolved production using 11-m(3) marine mesocosms (bags) in a Norwegian fjord with a salinity of 28.3, a chlorophyll concentration of 0.6 mu g L-1, an even biomass among five algal groups, and nitrogen...... between 17 and 58 in the P-replete bags. The C: P ratio of new DOM in the +Si bags was about 300 at all dosing regimes. Consequently, the range in N: P ratios was also large, with values from below 1 to about 30. Carbon-rich DOM in oceans and coastal waters is not necessarily a function of a slow...

  18. Why is relating plankton community structure to pelagic production ...

    African Journals Online (AJOL)

    mixing regulates primary production, and assuming certain features of food-chain length and efficiency, one can estimate fish yields. Fundamental to these arguments are assumptions concerning resource limitation which appear to be uncertain as generic marine pelagic characteristics, primarily that trophic levels are ...

  19. Fertilization of Earth Ponds. II: Effects on Plankton Communities ...

    African Journals Online (AJOL)

    A study of the effects of slurry inorganic and organic of fertilizers on the production of phyto-and zooplankton in earth ponds was conducted in Central Scotland, U.K. over a period of one year. For the inorganic fertilization, replicate ponds were treated with low and high phosphorus (LP, HP), high phosphorus and nitrogen ...

  20. Why is relating plankton community structure to pelagic production ...

    African Journals Online (AJOL)

    spamer

    The conceptual framework for quantitative marine ecology is attributable to Victor Hensen (1887), who pro- ... As fish were being “harvested” by man, it was argued that relationships .... carry their own functional chloroplasts or else derive.

  1. Carbon flows in natural plankton communities in the Anthropocene

    NARCIS (Netherlands)

    de Kluijver, A.

    2012-01-01

    Human activities have large impacts on organisms, ecosystems and biogeochemical cycling. A major human impact is the alteration of the global carbon cycle that lead to a rapid increase in atmospheric CO2 concentrations, which has been partially absorbed by the oceans, altering seawater chemistry and

  2. Catalytic Conversion of Carbohydrates

    DEFF Research Database (Denmark)

    Osmundsen, Christian Mårup

    a renewable route to aromatics. The conversion of biomass by high temperature processes is a desirable prospect due to the high volumetric production rates which can be achieved, and the ability of these types of processes to convert a wide range of substrates. Current processes however typically have rather...... with the production of commodity chemicals from the most abundantly available renewable source of carbon, carbohydrates. The production of alkyl lactates by the Lewis acid catalyzed conversion of hexoses is an interesting alternative to current fermentation based processes. A range of stannosilicates were...... to be an efficient initial conversion step in the utilization of biomass for chemicals production. The shift from an oil based chemical industry to one based on renewable resources is bound to happen sooner or later, however the environmental problems associated with the burning of fossil resources means...

  3. Myostatin and carbohydrate disturbances.

    Science.gov (United States)

    Assyov, Yavor S; Velikova, Tsvetelina V; Kamenov, Zdravko A

    2017-05-01

    Purpose/aim of the study: Myostatin is a myokine that has been shown to inhibit muscle growth and to have potentially deleterious effects on metabolism. The aim of the current study was to compare its circulating serum levels in subjects from the whole spectrum of carbohydrate disturbances leading to diabetes. A total of 159 age-, sex-, and BMI-matched subjects participated in the study - 50 had normal glucose tolerance (NGT), 60 had prediabetes (PreDM), and 49 had type 2 diabetes mellitus (T2D). Oral glucose tolerance testing was used to determine glucose tolerance. Serum myostatin was quantified by means of ELISA. Circulating serum myostatin levels were highest in patients with T2D, lower in subjects with prediabetes, and lowest in subjects with normoglycemia (all p Myostatin was shown to be positively associated with fasting plasma glucose, HOMA-IR, hepatic enzymes, uric acid, and FINDRISC questionnaire scores in both sexes. ROC analyses determined circulating myostatin levels to be of value for differentiating subjects with T2D (AUC = 0.72, p = 0.002 in men; AUC = 0.70, p = 0.004 in women) in the study population. After adjustment for potential confounders, in a multiple binary logistic regression model, serum myostatin added further information to traditional risk estimates in distinguishing subjects with T2D. Serum myostatin levels are higher with deterioration of carbohydrate tolerance. Furthermore, circulating myostatin is positively associated with traditional biochemical estimates of poor metabolic health. These data add to evidence of the involvement of this myokine in the pathogenesis of T2D.

  4. Life spans of planktonic foraminifers: New sight through sediment traps

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Saraswat, R.; Mazumder, A.

    ), indicated by black arrows are remarkably present for all three trap locations. (Modified after Curry et l.t 1992). 2002; Eguchi, Ujiie, Kawahata and Taira 2003), (ii) all the traps can not stop functioning simultaneously and that for the same time... estimates of the life spans of planktonic foraminifera based on extrapolation of lab culture observations. According to Be et al (1981), an inverse relationship exists between feeding frequency and survival time, and that planktonic foraminifers under...

  5. Synthesis of carbohydrate-based surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Pemberton, Jeanne E.; Polt, Robin L.; Maier, Raina M.

    2016-11-22

    The present invention provides carbohydrate-based surfactants and methods for producing the same. Methods for producing carbohydrate-based surfactants include using a glycosylation promoter to link a carbohydrate or its derivative to a hydrophobic compound.

  6. Intraseasonal patterns in coastal plankton biomass off central Chile derived from satellite observations and a biochemical model

    Science.gov (United States)

    Gomez, Fabian A.; Spitz, Yvette H.; Batchelder, Harold P.; Correa-Ramirez, Marco A.

    2017-10-01

    Subseasonal (5-130 days) environmental variability can strongly affect plankton dynamics, but is often overlooked in marine ecology studies. We documented the main subseasonal patterns of plankton biomass in the coastal upwelling system off central Chile, the southern part of the Humboldt System. Subseasonal variability was extracted from temporal patterns in satellite data of wind stress, sea surface temperature, and chlorophyll from the period 2003-2011, and from a realistically forced eddy-resolving physical-biochemical model from 2003 to 2008. Although most of the wind variability occurs at submonthly frequencies (< 30 days), we found that the dominant subseasonal pattern of phytoplankton biomass is within the intraseasonal band (30-90 days). The strongest intraseasonal coupling between wind and plankton is in spring-summer, when increased solar radiation enhances the phytoplankton response to upwelling. Biochemical model outputs show intraseasonal shifts in plankton community structure, mainly associated with the large fluctuations in diatom biomass. Diatom biomass peaks near surface during strong upwelling, whereas small phytoplankton biomass peaks at subsurface depths during relaxation or downwelling periods. Strong intraseasonally forced changes in biomass and species composition could strongly impact trophodynamics connections in the ecosystem, including the recruitment of commercially important fish species such as common sardine and anchovy. The wind-driven variability of chlorophyll concentration was connected to mid- and high-latitude atmospheric anomalies, which resemble disturbances with frequencies similar to the tropical Madden-Julian Oscillation.

  7. Crustacean Larvae-Vision in the Plankton.

    Science.gov (United States)

    Cronin, Thomas W; Bok, Michael J; Lin, Chan

    2017-11-01

    We review the visual systems of crustacean larvae, concentrating on the compound eyes of decapod and stomatopod larvae as well as the functional and behavioral aspects of their vision. Larval compound eyes of these macrurans are all built on fundamentally the same optical plan, the transparent apposition eye, which is eminently suitable for modification into the abundantly diverse optical systems of the adults. Many of these eyes contain a layer of reflective structures overlying the retina that produces a counterilluminating eyeshine, so they are unique in being camouflaged both by their transparency and by their reflection of light spectrally similar to background light to conceal the opaque retina. Besides the pair of compound eyes, at least some crustacean larvae have a non-imaging photoreceptor system based on a naupliar eye and possibly other frontal eyes. Larval compound-eye photoreceptors send axons to a large and well-developed optic lobe consisting of a series of neuropils that are similar to those of adult crustaceans and insects, implying sophisticated analysis of visual stimuli. The visual system fosters a number of advanced and flexible behaviors that permit crustacean larvae to survive extended periods in the plankton and allows them to reach acceptable adult habitats, within which to metamorphose. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  8. Ocean Acidification-Induced Restructuring of the Plankton Food Web Can Influence the Degradation of Sinking Particles

    Directory of Open Access Journals (Sweden)

    Paul Stange

    2018-04-01

    Full Text Available Ocean acidification (OA is expected to alter plankton community structure in the future ocean. This, in turn, could change the composition of sinking organic matter and the efficiency of the biological carbon pump. So far, most OA experiments involving entire plankton communities have been conducted in meso- to eutrophic environments. However, recent studies suggest that OA effects may be more pronounced during prolonged periods of nutrient limitation. In this study, we investigated how OA-induced changes in low-nutrient adapted plankton communities of the subtropical North Atlantic Ocean may affect particulate organic matter (POM standing stocks, POM fluxes, and POM stoichiometry. More specifically, we compared the elemental composition of POM suspended in the water column to the corresponding sinking material collected in sediment traps. Three weeks into the experiment, we simulated a natural upwelling event by adding nutrient-rich deep-water to all mesocosms, which induced a diatom-dominated phytoplankton bloom. Our results show that POM was more efficiently retained in the water column in the highest CO2 treatment levels (>800 μatm pCO2 subsequent to this bloom. We further observed significantly lower C:N and C:P ratios in post-bloom sedimented POM in the highest CO2 treatments, suggesting that degradation processes were less pronounced. This trend is most likely explained by differences in micro- and mesozooplankton abundance during the bloom and post-bloom phase. Overall, this study shows that OA can indirectly alter POM fluxes and stoichiometry in subtropical environments through changes in plankton community structure.

  9. Methodological challenges in carbohydrate analyses

    Directory of Open Access Journals (Sweden)

    Mary Beth Hall

    2007-07-01

    Full Text Available Carbohydrates can provide up to 80% of the dry matter in animal diets, yet their specific evaluation for research and diet formulation is only now becoming a focus in the animal sciences. Partitioning of dietary carbohydrates for nutritional purposes should reflect differences in digestion and fermentation characteristics and effects on animal performance. Key challenges to designating nutritionally important carbohydrate fractions include classifying the carbohydrates in terms of nutritional characteristics, and selecting analytical methods that describe the desired fraction. The relative lack of information on digestion characteristics of various carbohydrates and their interactions with other fractions in diets means that fractions will not soon be perfectly established. Developing a system of carbohydrate analysis that could be used across animal species could enhance the utility of analyses and amount of data we can obtain on dietary effects of carbohydrates. Based on quantities present in diets and apparent effects on animal performance, some nutritionally important classes of carbohydrates that may be valuable to measure include sugars, starch, fructans, insoluble fiber, and soluble fiber. Essential to selection of methods for these fractions is agreement on precisely what carbohydrates should be included in each. Each of these fractions has analyses that could potentially be used to measure them, but most of the available methods have weaknesses that must be evaluated to see if they are fatal and the assay is unusable, or if the assay still may be made workable. Factors we must consider as we seek to analyze carbohydrates to describe diets: Does the assay accurately measure the desired fraction? Is the assay for research, regulatory, or field use (affects considerations of acceptable costs and throughput? What are acceptable accuracy and variability of measures? Is the assay robust (enhances accuracy of values? For some carbohydrates, we

  10. Effects of nitrogen and phosphorus on the abundance and cell size of planktonic nanoflagellate communities Efeito da concentração de nitrogênio e fósforo na abundância e tamanho celular da comunidade de nanoflagelados planctônicos

    Directory of Open Access Journals (Sweden)

    Danielle Goeldner Pereira

    2012-12-01

    Full Text Available AIM: We experimentally investigated the effects of nutrients (Nitrogen and Phosphorus enrichment on the density, biomass, and cell size of pigmented and heterotrophic plankton nanoflagellates communities. METHODS: The experiment was done in mesocosms in a tropical reservoir during a 19-day period. Four different treatments were carried out: Control (non-nutrient addition - C, phosphorus additions (P, nitrogen addition (N and phosphorus + nitrogen addition (N + P. Each treatment was performed in triplicate, sorted randomly, thus giving a total of 12 experimental carboys, which were placed transversely in the middle of the reservoir. RESULTS: In general, pigmented and heterotrophic nanoflagellates fractions responded to nutrient addition, increasing densities and biomass values at the fertilized treatments. Opposed to expected, enriched treatments resulted in a slight decrease in mean cell size of the pigmented fraction. Moreover, in nutrient-rich treatments, pigmented nanoflagellates had higher relative abundance than in the control. CONCLUSIONS: Our results indicate that: i the density and biomass of nanoflagellates responded to the nutrient enrichment, mainly when N and P were added together; ii the pigmented and heterotrophic fractions showed distinct time responses to fertilization; iii the growth of nanoflagellate community seems to be co-limited by N and P; iv the nutrient enrichment led to a greater pigmented than heterotrophic fraction contribution; and v among the analyzed variables, nanoflagellate densities seem to be more sensitive to changes in nutrient availability than biomass or mean cell size.OBJETIVO: Investigamos experimentalmente o efeito da adição de nutrientes (Nitrogênio e Fósforo sobre a densidade e o tamanho celular da comunidade de nanoflagelados planctônicos pigmentados e heterotróficos. MÉTODOS: O experimento foi desenvolvido em mesocosmos num reservatório tropical durante 19 dias. Quatro diferentes tratamentos

  11. Variable Responses to Carbon Utilization between Planktonic and Biofilm Cells of a Human Carrier Strain of Salmonella enterica Serovar Typhi.

    Directory of Open Access Journals (Sweden)

    Kalaivani Kalai Chelvam

    Full Text Available Salmonella enterica serovar Typhi (S. Typhi is a foodborne pathogen that causes typhoid fever and infects only humans. The ability of S. Typhi to survive outside the human host remains unclear, particularly in human carrier strains. In this study, we have investigated the catabolic activity of a human carrier S. Typhi strain in both planktonic and biofilm cells using the high-throughput Biolog Phenotype MicroArray, Minimum Biofilm Eradication Concentration (MBEC biofilm inoculator (96-well peg lid and whole genome sequence data. Additional strains of S. Typhi were tested to further validate the variation of catabolism in selected carbon substrates in the different bacterial growth phases. The analyzes of the carbon utilization data indicated that planktonic cells of the carrier strain, S. Typhi CR0044 could utilize a broader range of carbon substrates compared to biofilm cells. Pyruvic acid and succinic acid which are related to energy metabolism were actively catabolised in the planktonic stage compared to biofilm stage. On the other hand, glycerol, L-fucose, L-rhamnose (carbohydrates and D-threonine (amino acid were more actively catabolised by biofilm cells compared to planktonic cells. Notably, dextrin and pectin could induce strong biofilm formation in the human carrier strain of S. Typhi. However, pectin could not induce formation of biofilm in the other S. Typhi strains. Phenome data showed the utilization of certain carbon substrates which was supported by the presence of the catabolism-associated genes in S. Typhi CR0044. In conclusion, the findings showed the differential carbon utilization between planktonic and biofilm cells of a S. Typhi human carrier strain. The differences found in the carbon utilization profiles suggested that S. Typhi uses substrates mainly found in the human biliary mucus glycoprotein, gallbladder, liver and cortex of the kidney of the human host. The observed diversity in the carbon catabolism profiles among

  12. Carbohydrates of human immunodeficiency virus

    DEFF Research Database (Denmark)

    Hansen, J E

    1992-01-01

    Elucidation of the mechanism by which viral infection induces the appearance of carbohydrate neoantigens is highly important. Results from such studies could be expected to be significant for a general understanding of the regulation of glycosylation, and perhaps especially important for the unde......Elucidation of the mechanism by which viral infection induces the appearance of carbohydrate neoantigens is highly important. Results from such studies could be expected to be significant for a general understanding of the regulation of glycosylation, and perhaps especially important...... therapy with glycosylation enzyme inhibitors will, however, require the development of more specific and less toxic compounds. If carbohydrate antigens can elicit a neutralizing immune response in vivo, the possibility exists that carbohydrate neoantigens can be utilized in the construction of a vaccine...

  13. Facultative thermogenesis induced by carbohydrate

    DEFF Research Database (Denmark)

    Astrup, A; Bülow, J; Christensen, N J

    1986-01-01

    In addition to the obligatory thermogenesis due to processing and storage, carbohydrate ingestion is accompanied by a facultative thermogenesis mediated by catecholamines via beta-adrenoceptors. The anatomical origin of facultative thermogenesis has hitherto not been determined. The possible...

  14. Transition metals in carbohydrate chemistry

    DEFF Research Database (Denmark)

    Madsen, Robert

    1997-01-01

    This review describes the application of transition metal mediated reactions in carbohydrate synthesis. The different metal mediated transformations are divided into reaction types and illustrated by various examples on monosaccharide derivatives. Carbon-carbon bond forming reactions are further ...

  15. Comparing the responses of rumen ciliate protozoa and bacteria to excess carbohydrate.

    Science.gov (United States)

    Teixeira, César R V; Lana, Rogério de Paula; Tao, Junyi; Hackmann, Timothy J

    2017-06-01

    When given excess carbohydrate, certain microbial species respond by storing energy (synthesizing reserve carbohydrate), but other species respond by dissipating the energy as heat (spilling energy). To determine the importance of these responses in the rumen microbial community, this study quantified the responses of mixed ciliate protozoa vs bacteria to glucose. We hypothesized that ciliates would direct more glucose to synthesis of reserve carbohydrate (and less to energy spilling) than would bacteria. Ciliates and bacteria were isolated from rumen fluid using filtration and centrifugation, resuspended in nitrogen-free buffer to limit growth, and dosed with 5 mM glucose. Compared with bacteria, ciliates consumed glucose >3-fold faster and synthesized reserve carbohydrate 4-fold faster. They incorporated 53% of glucose carbon into reserve carbohydrate-nearly double the value (27%) for bacteria. Energy spilling was not detected for ciliates, as all heat production (104%) was accounted by synthesis of reserve carbohydrate and endogenous metabolism. For bacteria, reserve carbohydrate and endogenous metabolism accounted for only 68% of heat production, and spilling was detected within 11 min of dosing glucose. These results suggest that ciliates alter the course of ruminal carbohydrate metabolism by outcompeting bacteria for excess carbohydrate, maximizing reserve carbohydrate synthesis, and minimizing energy spilling. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Racemic carbohydrates - fact or fiction?

    DEFF Research Database (Denmark)

    Senning, Alexander Erich Eugen

    2007-01-01

    Chemical Abstracts Service has developed unsound practices in the naming and handling of simple carbohydrates such as aldopentoses 1, aldohexoses 2, and ketohexoses 3. Typically, the common name glucose is sometimes, inappropriately, interpreted as meaning DL-glucose DL-2d. Thus, a considerable...... number of CA names and registry numbers have been created for non-existing racemic carbohydrates and linked to irrelevant references which, moreover, in many cases cannot be retrieved by the SciFinder Scholar program....

  17. Planktonic benthonic foraminiferal ratios: Modern patterns and Tertiary applicability

    Science.gov (United States)

    Gibson, T.G.

    1989-01-01

    The abundance of planktonic specimens in foraminiferal assemblages was determined in numerous bottom samples from inner neritic to deep oceanic depths along the Atlantic margin of the northeastern United States. The results augment previous studies in other areas that have shown a general increase in percentage of planktonic specimens in total foraminiferal bottom assemblages as water depth increases. The patterns found in this area of complex shelf bathymetry and hydrography illustrate the influence on the planktonic-benthonic percentages of water depth, distance from shore, different water mass properties and downslope movement of tests in high energy areas. The patterns found in the 661 samples from the Atlantic margin were compared with results from 795 stations in the Gulf of Mexico, Pacific Ocean and Red Sea. The relative abundance of planktonic specimens and water depth correlates positively in all open oceanic areas even though taxonomic composition and diversity of the faunas from different areas is variable. The variation of planktonic percentages in bottom samples within most depth intervals is large so that a precise depth determination cannot be made for any given value. However, an approximate upper depth limit for given percentages can be estimated for open ocean environments. A decrease in planktonic percentages is seen in the lower salinity and higher turbidity coastal waters of the Gulf of Maine. Planktonic percentages intermediate between the lower values in the less saline coastal waters and the higher values in the normal open oceanic conditions occur in the transitional area between the Gulf of Maine and the open marine Atlantic Ocean to the east. Similarly lowered values in another area of restricted oceanic circulation occur in the high salinity, clear, but nutrient-poor waters of the Gulf of Aqaba off the Red Sea. A comparison of the similarity of modern planktonic percentage values to those found in earlier Tertiary assemblages was made to

  18. A long-term study on crustacean plankton of a shallow tropical lake: the role of invertebrate predation

    Directory of Open Access Journals (Sweden)

    Marlene S. Arcifa

    2015-06-01

    Full Text Available The primary factor that governs the size and species composition of zooplankton is still a controversial issue and temperature is considered the main factor responsible for latitudinal differences. In waters with a narrow temperature range, such as in the tropics, predation may be a more important factor. Nearly three decades of intermittent studies of the crustacean plankton in a shallow tropical lake revealed that the main event that led to their restructuring was the appearance of a second predator, the water mite Krendowskia sp. The new predator and larvae of the dipteran Chaoborus brasiliensis Theobald exerted a combined, although asymmetrical effect on microcrustaceans. The period when the mite was detected was followed by the restructuring of the crustacean plankton community. Predation by these two invertebrates emerged as the factor responsible for community changes, involving an increased contribution of copepods and decreases in the relative abundance of smaller cladoceran species. In the short term, the mite caused a decrease in species richness and the annual mean instantaneous composition of cladocerans, a predominance of large-sized species (Daphnia ambigua Scourfield and Daphnia gessneri Herbst and the virtual disappearance of small species (e.g., Bosmina tubicen Brehm. The long-term impact resulted in increased species richness and the dominance of large and medium-sized cladocerans, such as D. gessneri and Ceriodaphnia richardi Sars. The larger body size of three cladocerans, the two Daphnia species and B. tubicen, in the long term, may be a response to the dominant predator, Chaoborus. The seasonal variation in the predator abundance, mainly Chaoborus larvae, allowed the prey to recover during the cool season. The copepods Tropocyclops prasinus meridionalis (Fischer and Thermocyclops decipiens Kiefer were less affected by predation than the cladocerans; their contribution to the crustacean plankton increased 12-28% after the

  19. Planktonic food web structure at a coastal time-series site: I. Partitioning of microbial abundances and carbon biomass

    Science.gov (United States)

    Caron, David A.; Connell, Paige E.; Schaffner, Rebecca A.; Schnetzer, Astrid; Fuhrman, Jed A.; Countway, Peter D.; Kim, Diane Y.

    2017-03-01

    Biogeochemistry in marine plankton communities is strongly influenced by the activities of microbial species. Understanding the composition and dynamics of these assemblages is essential for modeling emergent community-level processes, yet few studies have examined all of the biological assemblages present in the plankton, and benchmark data of this sort from time-series studies are rare. Abundance and biomass of the entire microbial assemblage and mesozooplankton (>200 μm) were determined vertically, monthly and seasonally over a 3-year period at a coastal time-series station in the San Pedro Basin off the southwestern coast of the USA. All compartments of the planktonic community were enumerated (viruses in the femtoplankton size range [0.02-0.2 μm], bacteria + archaea and cyanobacteria in the picoplankton size range [0.2-2.0 μm], phototrophic and heterotrophic protists in the nanoplanktonic [2-20 μm] and microplanktonic [20-200 μm] size ranges, and mesozooplankton [>200 μm]. Carbon biomass of each category was estimated using standard conversion factors. Plankton abundances varied over seven orders of magnitude across all categories, and total carbon biomass averaged approximately 60 μg C l-1 in surface waters of the 890 m water column over the study period. Bacteria + archaea comprised the single largest component of biomass (>1/3 of the total), with the sum of phototrophic protistan biomass making up a similar proportion. Temporal variability at this subtropical station was not dramatic. Monthly depth-specific and depth-integrated biomass varied 2-fold at the station, while seasonal variances were generally web structure and function at this coastal observatory.

  20. Extinction, recolonization, and dispersal through time in a planktonic crustacean.

    Science.gov (United States)

    Mergeay, Joachim; Vanoverbeke, Joost; Verschuren, Dirk; De Meester, Luc

    2007-12-01

    Dormant propagule banks are important reservoirs of biological and genetic diversity of local communities and populations and provide buffering mechanisms against extinction. Although dormant stages of various plant and animal species are known to remain viable for decades and even centuries, little is known about the effective influence of recolonization from such old sources on the genetic continuity of intermittent populations under natural conditions. Using recent and old dormant eggs recovered from a dated lake sediment core in Kenya, we traced the genetic composition of a local population of the planktonic crustacean Daphnia barbata through a sequence of extinction and recolonization events. This was combined with a phylogeographic and population-genetic survey of regional populations. Four successive populations, fully separated in time, inhabited Lake Naivasha from ca. 1330 to 1570 AD, from ca. 1610 to 1720 AD, from ca. 1840 to 1940 AD, and from 1995 to the present (2001 AD). Our results strongly indicate genetic continuity between the 1840-1940 and 1995-2001 populations, which are separated in time by at least 50 years, and close genetic relatedness of them both to the 1330-1580 population. A software tool (Colonize) was developed to find the most likely source population of the refounded 1995-2001 population and to test the number of colonists involved in the recolonization event. The results confirmed that the 1995-2001 population most probably developed out of a limited number of surviving local dormant eggs from the previous population, rather than out of individuals from regional (central and southern Kenya) or more distant (Ethiopia, Zimbabwe) populations that may have immigrated to Lake Naivasha through passive dispersal. These results emphasize the importance of prolonged dormancy for the natural long-term dynamics of crustacean zooplankton in fluctuating environments and suggest an important role of old local dormant egg banks in aquatic habitat

  1. Plankton of Southern Chilean fjords: trends and linkages

    Directory of Open Access Journals (Sweden)

    Tarcisio Antezana

    1999-12-01

    Full Text Available The present paper compiles and reviews past and recent results from Magellan and Fuegian fjords for an overview of the planktonic assemblage there. It first examines linkages to local, adjacent and remote environments. The plankton assemblage presents deviations from the biota of the Magellan biogeographic Province, where the occasional presence of Antarctic species is related to oceanographic phenomena at the Polar Front. Complex bathymetric and hydrographic features within the fjords suggest that the plankton is rather isolated. Adaptations and constraints for population survival, and the role of diel migrators and gregarious zooplankters with regard to bentho-pelagic coupling are discussed. Results on seasonal differences in the plankton of the largest and most isolated basin of the Strait of Magellan are compiled. In spring the plankton was dominated by large diatoms suggesting a short food chain where most of the phytoplankton bloom goes to the bottom, to the meroplankton and to a few dominant holoplankters. In summer, the phytoplankton was dominated by pico- and nanophytoplankton suggesting a more complex food web mediated by a bacterial loop. High abundance of holo- and meroplanktonic larvae coincided with spring blooming conditions.

  2. The biomass of the deep-sea benthopelagic plankton

    Science.gov (United States)

    Wishner, K. F.

    1980-04-01

    Deep-sea benthopelagic plankton samples were collected with a specially designed opening-closing net system 10 to 100 m above the bottom in five different oceanic regions at depths from 1000 to 4700 m. Benthopelagic plankton biomasses decrease exponentially with depth. At 1000 m the biomass is about 1% that of the surface zooplankton, at 5000 m about 0.1%. Effects of differences in surface primary productivity on deep-sea plankton biomass are much less than the effect of depth and are detectable only in a few comparisons of extreme oceanic regions. The biomass at 10 m above the bottom is greater than that at 100 m above the bottom (in a three-sample comparison), which could be a consequence of an enriched near-bottom environment. The deep-sea plankton biomass in the Red Sea is anomalously low. This may be due to increased decomposition rates in the warm (22°C) deep Red Sea water, which prevent much detritus from reaching the deep sea. A model of organic carbon utilization in the benthic boundary layer (bottom 100 m), incorporating results from deep-sea sediment trap and respiration studies, indicates that the benthopelagic plankton use only a small amount of the organic carbon flux. A large fraction of the flux is unaccounted for by present estimates of benthic and benthopelagic respiration.

  3. Radionuclides in plankton from the South Pacific Basin

    International Nuclear Information System (INIS)

    Marsh, K.V.; Buddemeier, R.W.

    1984-01-01

    An investigation has been initiated of the utility of marine plankton as bioconcentrating samplers of low-level marine radioactivity in the southern hemisphere. A literature review has shown that both freshwater and marine plankton have trace element and radionuclide concentration factors (relative to water) of up to 10 4 . In 1956 and 1958 considerable work was done on the accumulation and distribution of a variety of fission and activation products produced by nuclear tests in the Marshall Islands. Since then, studies, have largely been confined to a few radionuclides, and most of the work in the last twenty years has been done in the northern hemisphere. The authors participated in Operations Deepfreeze 1981 and 1982, collecting a total of 48 plankton samples from the USCGC Glacier on its Antarctic cruises. Battelle Pacific Northwest Laboratories sampled air, water, rain, and fallout. The authors were able to measure concentrations in plankton of the naturally-occurring radionuclides 7 Be, 40 K, and the U and Th series, and they believe that they have detected low levels of 144 Ce and 95 Nb in seven samples ranging as far south as 68 0 . Biological identification of the plankton suggests a possible correlation between radionuclide concentration and the protozoa content of the samples. 7 references, 5 figures, 1 table

  4. Continuous daylight in the high-Arctic summer supports high plankton respiration rates compared to those supported in the dark

    KAUST Repository

    Mesa, Elena; Delgado-Huertas, Antonio; Carrillo-de-Albornoz, Paloma; Garcí a-Corral, Lara S.; Sanz-Martí n, Marina; Wassmann, Paul; Reigstad, Marit; Sejr, Mikael; Dalsgaard, Tage; Duarte, Carlos M.

    2017-01-01

    Plankton respiration rate is a major component of global CO2 production and is forecasted to increase rapidly in the Arctic with warming. Yet, existing assessments in the Arctic evaluated plankton respiration in the dark. Evidence that plankton

  5. Complexes of natural carbohydrates with metal cations

    International Nuclear Information System (INIS)

    Alekseev, Yurii E; Garnovskii, Alexander D; Zhdanov, Yu A

    1998-01-01

    Data on the interaction of natural carbohydrates (mono-, oligo-, and poly-saccharides, amino sugars, and natural organic acids of carbohydrate origin) with metal cations are surveyed and described systematically. The structural diversity of carbohydrate metal complexes, caused by some specific features of carbohydrates as ligands, is demonstrated. The influence of complex formation on the chemical properties of carbohydrates is discussed. It is shown that the formation of metal complexes plays an important role in the configurational and conformational analysis of carbohydrates. The practical significance of the coordination interaction in the series of carbohydrate ligands is demonstrated. The bibliography includes 571 references.

  6. Can nearby eutrophic reservoirs sustain a differentiated biodiversity of planktonic microcrustaceans in a tropical semiarid basin?

    Science.gov (United States)

    Diniz, Leidiane P; Melo-Júnior, Mauro DE

    2017-01-01

    This paper aims to compare alpha and beta diversities of planktonic microcrustaceans from three reservoirs located nearby in a tropical semiarid basin. Our hypothesis was that alpha and beta diversities of the community are different, although the ecosystems are located close to each other. We carried out two sampling campaigns: dry and rainy seasons. The sampling of microcrustaceans and environmental variables (dissolved oxygen, chlorophyll a and nutrient) was performed at twelve stations and were distributed throughout the three zones (river, transition, and lacustrine), using a plankton net (45 µm). The reservoirs showed different uses and types of nitrogen predominance: Cachoeira (supply/nitrate), Borborema (sewage/ammonia) and Saco (aquaculture/ammonia). Seventeen species were recorded whose richness was assessed as particularly specific to each one of the studied reservoirs. Seasonally, both reservoirs with high anthropogenic alteration showed greater richness in the dry season. The three reservoirs located in a same basin showed different richness and composition, but the diversity did not differ between the zones of the reservoirs. Although communities are close to each other, their composition and richness were found to be distinct for each reservoir. This may be in response to the peculiar particularities, such as nitrogen sources and the different uses.

  7. Can nearby eutrophic reservoirs sustain a differentiated biodiversity of planktonic microcrustaceans in a tropical semiarid basin?

    Directory of Open Access Journals (Sweden)

    LEIDIANE P. DINIZ

    Full Text Available ABSTRACT This paper aims to compare alpha and beta diversities of planktonic microcrustaceans from three reservoirs located nearby in a tropical semiarid basin. Our hypothesis was that alpha and beta diversities of the community are different, although the ecosystems are located close to each other. We carried out two sampling campaigns: dry and rainy seasons. The sampling of microcrustaceans and environmental variables (dissolved oxygen, chlorophyll a and nutrient was performed at twelve stations and were distributed throughout the three zones (river, transition, and lacustrine, using a plankton net (45 µm. The reservoirs showed different uses and types of nitrogen predominance: Cachoeira (supply/nitrate, Borborema (sewage/ammonia and Saco (aquaculture/ammonia. Seventeen species were recorded whose richness was assessed as particularly specific to each one of the studied reservoirs. Seasonally, both reservoirs with high anthropogenic alteration showed greater richness in the dry season. The three reservoirs located in a same basin showed different richness and composition, but the diversity did not differ between the zones of the reservoirs. Although communities are close to each other, their composition and richness were found to be distinct for each reservoir. This may be in response to the peculiar particularities, such as nitrogen sources and the different uses.

  8. Ecology and distribution of recent planktonic foraminifera in eastern part of Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Kutty, M.K.

    Thirty species of living planktonic foraminifera have been studied from 97 plankton tows collected from the eastern Arabian Sea with an accent on their ecological and distributional aspects. Species density is higher with less dominance in the deep...

  9. Radiolysis of carbohydrates and of carbohydrate-containing foodstuffs

    International Nuclear Information System (INIS)

    Diehl, J.F.; Adam, S.; Delincee, H.; Jakubick, V.

    1978-01-01

    Toxicological evaluation of irradiated foodstuffs requires knowledge of radiation-induced chemical changes. A review of the literature reveals much information on the radiation chemistry of pure substances, e.g., dilute solutions of individual carbohydrates. Much less is known about the interactions of food constituents during irradiation. In an effort to remedy this situation, radiation effects on various compounds have been studied in systems of increasing complexity. In one approach, gas chromatography was used to investigate the radiolysis of tehalose in pure solution and in the presence of amino acids or proteins. In another approach, radiation-induced aggregation of proteins and of [ 14 C]tryptophan with proteins was studied in the absence and presence of carbohydrates (trehalose, starch), emulsified sunfower oil, and a mixture of carbohydrates and emulsified sunflower oil

  10. Influence of plankton metabolism and mixing depth on CO2 dynamics in an Amazon floodplain lake.

    Science.gov (United States)

    Amaral, João Henrique F; Borges, Alberto V; Melack, John M; Sarmento, Hugo; Barbosa, Pedro M; Kasper, Daniele; de Melo, Michaela L; De Fex-Wolf, Daniela; da Silva, Jonismar S; Forsberg, Bruce R

    2018-07-15

    We investigated plankton metabolism and its influence on carbon dioxide (CO 2 ) dynamics in a central Amazon floodplain lake (Janauacá, 3°23' S, 60°18' W) from September 2015 to May 2016, including a period with exceptional drought. We made diel measurements of CO 2 emissions to the atmosphere with floating chambers and depth profiles of temperature and CO 2 partial pressure (pCO 2 ) at two sites with differing wind exposure and proximity to vegetated habitats. Dissolved oxygen (DO) concentrations were monitored continuously during day and night in clear and dark chambers with autonomous optical sensors to evaluate plankton metabolism. Overnight community respiration (CR), and gross primary production (GPP) rates were higher in clear chambers and positively correlated with chlorophyll-a (Chl-a). CO 2 air-water fluxes varied over 24-h periods with changes in thermal structure and metabolism. Most net daily CO 2 fluxes during low water and mid-rising water at the wind exposed site were into the lake as a result of high rates of photosynthesis. All other measurements indicated net daily release to the atmosphere. Average GPP rates (6.8gCm -2 d -1 ) were high compared with other studies in Amazon floodplain lakes. The growth of herbaceous plants on exposed sediment during an exceptional drought led to large carbon inputs when these areas were flooded, enhancing CR, pCO 2 , and CO 2 fluxes. During the period when the submerged herbaceous vegetation decayed phytoplankton abundance increased and photosynthetic uptake of CO 2 occurred. While planktonic metabolism was often autotrophic (GPP:CR>1), CO 2 out-gassing occurred during most periods investigated indicating other inputs of carbon such as sediments or soils and wetland plants. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth.

    Science.gov (United States)

    Luef, Birgit; Fakra, Sirine C; Csencsits, Roseann; Wrighton, Kelly C; Williams, Kenneth H; Wilkins, Michael J; Downing, Kenneth H; Long, Philip E; Comolli, Luis R; Banfield, Jillian F

    2013-02-01

    Iron-reducing bacteria (FeRB) play key roles in anaerobic metal and carbon cycling and carry out biogeochemical transformations that can be harnessed for environmental bioremediation. A subset of FeRB require direct contact with Fe(III)-bearing minerals for dissimilatory growth, yet these bacteria must move between mineral particles. Furthermore, they proliferate in planktonic consortia during biostimulation experiments. Thus, a key question is how such organisms can sustain growth under these conditions. Here we characterized planktonic microbial communities sampled from an aquifer in Rifle, Colorado, USA, close to the peak of iron reduction following in situ acetate amendment. Samples were cryo-plunged on site and subsequently examined using correlated two- and three-dimensional cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission X-ray microscopy (STXM). The outer membranes of most cells were decorated with aggregates up to 150 nm in diameter composed of ∼3 nm wide amorphous, Fe-rich nanoparticles. Fluorescent in situ hybridization of lineage-specific probes applied to rRNA of cells subsequently imaged via cryo-TEM identified Geobacter spp., a well-studied group of FeRB. STXM results at the Fe L(2,3) absorption edges indicate that nanoparticle aggregates contain a variable mixture of Fe(II)-Fe(III), and are generally enriched in Fe(III). Geobacter bemidjiensis cultivated anaerobically in the laboratory on acetate and hydrous ferric oxyhydroxides also accumulated mixed-valence nanoparticle aggregates. In field-collected samples, FeRB with a wide variety of morphologies were associated with nano-aggregates, indicating that cell surface Fe(III) accumulation may be a general mechanism by which FeRB can grow while in planktonic suspension.

  12. Responses of marine plankton to pollutant stress

    DEFF Research Database (Denmark)

    Hjorth, M.

    to reveal indirect effects and co-effects with the abiotic environment on three trophic levels, namely bacteria, phytoplankton and zooplankton. The role of mesocosms and community studies in risk assessment and their usefulness in integrating ecological knowledge into ecotoxicology is discussed...... with examples of work done on natural communities of phytoplankton and zooplankton. Abiotic conditions such as UV light and nutrient concentrations are shown to influence pollutant effects....

  13. Aminooxylated Carbohydrates: Synthesis and Applications.

    Science.gov (United States)

    Pifferi, Carlo; Daskhan, Gour Chand; Fiore, Michele; Shiao, Tze Chieh; Roy, René; Renaudet, Olivier

    2017-08-09

    Among other classes of biomolecules, carbohydrates and glycoconjugates are widely involved in numerous biological functions. In addition to addressing the related synthetic challenges, glycochemists have invested intense efforts in providing access to structures that can be used to study, activate, or inhibit these biological processes. Over the past few decades, aminooxylated carbohydrates have been found to be key building blocks for achieving these goals. This review provides the first in-depth overview covering several aspects related to the syntheses and applications of aminooxylated carbohydrates. After a brief introduction to oxime bonds and their relative stabilities compared to related C═N functions, synthetic aspects of oxime ligation and methodologies for introducing the aminooxy functionality onto both glycofuranosyls and glycopyranosyls are described. The subsequent section focuses on biological applications involving aminooxylated carbohydrates as components for the construcion of diverse architectures. Mimetics of natural structures represent useful tools for better understanding the features that drive carbohydrate-receptor interaction, their biological output and they also represent interesting structures with improved stability and tunable properties. In the next section, multivalent structures such as glycoclusters and glycodendrimers obtained through oxime ligation are described in terms of synthetic design and their biological applications such as immunomodulators. The second-to-last section discusses miscellaneous applications of oxime-based glycoconjugates, such as enantioselective catalysis and glycosylated oligonucleotides, and conclusions and perspectives are provided in the last section.

  14. Global marine plankton functional type biomass distributions : Phaeocystis spp

    NARCIS (Netherlands)

    Vogt, M.; O'Brien, C.; Peloquin, J.; Schoemann, V.; Breton, E.; Estrada, M.; Gibson, J.; Karentz, D.; van Leeuwe, M. A.; Stefels, J.; Widdicombe, C.; Peperzak, L.

    2012-01-01

    The planktonic haptophyte Phaeocystis has been suggested to play a fundamental role in the global biogeochemical cycling of carbon and sulphur, but little is known about its global biomass distribution. We have collected global microscopy data of the genus Phaeocystis and converted abundance data to

  15. Holocene planktonic foraminifera from the shelf sediments off Kerala Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Twenty-two planktonic foraminifers were identified from a few samples collected aboard INS KISTNA at 9~'N and 76~'E, at 89 metres depth from the bottom sediment-water interface. A few of the more characteristic features of each are described. Some...

  16. Ether lipids of planktonic archae in the marine water column

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Hoefs, M.J.L.; Schouten, S.; King, L.L.; Wakeham, S.G.; Leeuw, J.W. de

    1997-01-01

    Acyclic and cyclic biphytanes derived from the membrane ether lipids of archaea were found in water column particulate and sedimentary organic matter from several oxic and anoxic marine environments. Compound-specific isotope analyses of the carbon skeletons suggest that planktonic archaea utilize

  17. Ecological partitioning and diversity in tropical planktonic foraminifera

    Directory of Open Access Journals (Sweden)

    Seears Heidi A

    2012-04-01

    Full Text Available Abstract Background Ecological processes are increasingly being viewed as an important mode of diversification in the marine environment, where the high dispersal potential of pelagic organisms, and a lack of absolute barriers to gene flow may limit the occurrence of allopatric speciation through vicariance. Here we focus on the potential role of ecological partitioning in the diversification of a widely distributed group of marine protists, the planktonic foraminifera. Sampling was conducted in the tropical Arabian Sea, during the southwest (summer monsoon, when pronounced environmental conditions result in a strong disparity in temperature, salinity and productivity between distinct northern and southern water masses. Results We uncovered extensive genetic diversity within the Arabian Sea planktonic foraminifera, identifying 13 morphospecies, represented by 20 distinct SSU rRNA genetic types. Several morphospecies/genetic types displayed non-random biogeographical distributions, partitioning between the northern and southern water masses, giving a strong indication of independent ecological adaptations. Conclusions We propose sea-surface primary productivity as the main factor driving the geographical segregation of Arabian Sea planktonic foraminifera, during the SW monsoon, with variations in symbiotic associations possibly playing a role in the specific ecological adaptations observed. Our findings suggest that ecological partitioning could be contributing to the high levels of 'cryptic' genetic diversity observed within the planktonic foraminifera, and support the view that ecological processes may play a key role in the diversification of marine pelagic organisms.

  18. Een methode ter bepaling van de respiratieaktiviteit in marien plankton

    NARCIS (Netherlands)

    Lambeck, R.H.D.

    1973-01-01

    The usefulness of a method, described by T.T. Packard (1971), for the determination of the potential respiratory rate in marine plankton, based on the use of tetrazolium dye, was tested. Especially the influence of a few aspects of the homogenisation procedure on the final results was investigated.

  19. Planktonic Biodiversity of Bhoj Wetland, Bhopal, India | Neelam ...

    African Journals Online (AJOL)

    Biodiversity found on Earth today consists of many millions of distinct biological species, which is the product of nearly 3.5 billion years of evolution. This article deals with planktonic distribution of Bhoj Wetland, Bhopal, India . Bhoj Wetland comprises of two lakes i.e. Upper and Lower lakes of Bhopal. The Upper lake is ...

  20. Assimilation of Ocean-Color Plankton Functional Types to Improve Marine Ecosystem Simulations

    Science.gov (United States)

    Ciavatta, S.; Brewin, R. J. W.; Skákala, J.; Polimene, L.; de Mora, L.; Artioli, Y.; Allen, J. I.

    2018-02-01

    We assimilated phytoplankton functional types (PFTs) derived from ocean color into a marine ecosystem model, to improve the simulation of biogeochemical indicators and emerging properties in a shelf sea. Error-characterized chlorophyll concentrations of four PFTs (diatoms, dinoflagellates, nanoplankton, and picoplankton), as well as total chlorophyll for comparison, were assimilated into a physical-biogeochemical model of the North East Atlantic, applying a localized Ensemble Kalman filter. The reanalysis simulations spanned the years 1998-2003. The skill of the reference and reanalysis simulations in estimating ocean color and in situ biogeochemical data were compared by using robust statistics. The reanalysis outperformed both the reference and the assimilation of total chlorophyll in estimating the ocean-color PFTs (except nanoplankton), as well as the not-assimilated total chlorophyll, leading the model to simulate better the plankton community structure. Crucially, the reanalysis improved the estimates of not-assimilated in situ data of PFTs, as well as of phosphate and pCO2, impacting the simulation of the air-sea carbon flux. However, the reanalysis increased further the model overestimation of nitrate, in spite of increases in plankton nitrate uptake. The method proposed here is easily adaptable for use with other ecosystem models that simulate PFTs, for, e.g., reanalysis of carbon fluxes in the global ocean and for operational forecasts of biogeochemical indicators in shelf-sea ecosystems.

  1. Anthropogenic shift of planktonic food web structure in a coastal lagoon by freshwater flow regulation

    Science.gov (United States)

    Hemraj, Deevesh A.; Hossain, A.; Ye, Qifeng; Qin, Jian G.; Leterme, Sophie C.

    2017-03-01

    Anthropogenic modification of aquatic systems has diverse impacts on food web interactions and ecosystem states. To reverse the adverse effects of modified freshwater flow, adequate management of discharge is required, especially due to higher water requirements and abstractions for human use. Here, we look at the effects of anthropogenically controlled freshwater flow regimes on the planktonic food web of a Ramsar listed coastal lagoon that is under recovery from degradation. Our results show shifts in water quality and plankton community interactions associated to changes in water flow. These shifts in food web interactions represent modifications in habitat complexity and water quality. At high flow, phytoplankton-zooplankton interactions dominate the food web. Conversely, at low flow, bacteria, viruses and nano/picoplankton interactions are more dominant, with a substantial switch of the food web towards heterotrophy. This switch can be associated with excess organic matter loading, decomposition of dead organisms, and synergistic and antagonistic interactions. We suggest that a lower variability in flow amplitude could be beneficial for the long-term sustaining of water quality and food web interactions, while improving the ecosystem health of systems facing similar stresses as the Coorong.

  2. The response of calcifying plankton to climate change in the Pliocene

    Directory of Open Access Journals (Sweden)

    C. V. Davis

    2013-09-01

    Full Text Available As a result of anthropogenic pCO2 increases, future oceans are growing warmer and lower in pH and oxygen, conditions that are likely to impact planktic communities. Past intervals of elevated and changing pCO2 and temperatures can offer a glimpse into the response of marine calcifying plankton to changes in surface oceans under conditions similar to those projected for the future. Here we present new records of planktic foraminiferal and coccolith calcification (weight and size from Deep Sea Drilling Project Site 607 (mid-North Atlantic and Ocean Drilling Program Site 999 (Caribbean Sea from the Pliocene, the last time that pCO2 was similar to today, and extending through a global cooling event into the intensification of Northern Hemisphere glaciation (3.3 to 2.6 million years ago. Test weights of both surface-dwelling Foraminifera Globigerina bulloides and thermocline-dwelling Foraminifera Globorotalia puncticulata vary with a potential link to regional temperature variation in the North Atlantic, whereas in the tropics Globigerinoides ruber test weight remains stable. In contrast, reticulofenestrid coccoliths show a narrowing size range and a decline in the largest lith diameters over this interval. Our results suggest no major changes in plankton calcite production during the high pCO2 Pliocene or during the transition into an icehouse world.

  3. Marine Group II Dominates Planktonic Archaea in Water Column of the Northeastern South China Sea

    Directory of Open Access Journals (Sweden)

    Haodong Liu

    2017-06-01

    Full Text Available Temperature, nutrients, and salinity are among the important factors constraining the distribution and abundance of microorganisms in the ocean. Marine Group II (MGII belonging to Euryarchaeota commonly dominates the planktonic archaeal community in shallow water and Marine Group I (MGI, now is called Thaumarchaeota in deeper water in global oceans. Results of quantitative PCR (qPCR and 454 sequencing in our study, however, showed the dominance of MGII in planktonic archaea throughout the water column of the northeastern South China Sea (SCS that is characterized by strong water mixing. The abundance of ammonia-oxidizing archaea (AOA representing the main group of Thaumarchaeota in deeper water in the northeastern SCS was significantly lower than in other oceanic regions. Phylogenetic analysis showed that the top operational taxonomic units (OTUs of the MGII occurring predominantly below 200 m depth may be unique in the northeastern SCS based on the observation that they are distantly related to known sequences (identity ranging from 90–94%. The abundance of MGII was also significantly correlated with total bacteria in the whole column, which may indicate that MGII and bacteria may have similar physiological or biochemical properties or responses to environmental variation. This study provides valuable information about the dominance of MGII over AOA in both shallow and deep water in the northeastern SCS and highlights the need for comprehensive studies integrating physical, chemical, and microbial oceanography.

  4. Community

    Science.gov (United States)

    stability Science & Innovation Collaboration Careers Community Environment Science & Innovation Recruitment Events Community Commitment Giving Campaigns, Drives Economic Development Employee Funded neighbor pledge: contribute to quality of life in Northern New Mexico through economic development

  5. Chemical ecology of the marine plankton.

    Science.gov (United States)

    Roy, Jessie S; Poulson-Ellestad, Kelsey L; Drew Sieg, R; Poulin, Remington X; Kubanek, Julia

    2013-10-11

    This review summarizes recent work in the chemical ecology of pelagic marine ecosystems. In order to provide a comprehensive overview of advances in the field over the period covered, we have organized this review by ecological interaction type beginning with intraspecific interactions, then interspecific interactions (including mutualism, parasitism, competition, and predation), and finally community- and ecosystem-wide interactions.

  6. Carbohydrates of human immunodeficiency virus

    DEFF Research Database (Denmark)

    Hansen, J E

    1992-01-01

    Elucidation of the mechanism by which viral infection induces the appearance of carbohydrate neoantigens is highly important. Results from such studies could be expected to be significant for a general understanding of the regulation of glycosylation, and perhaps especially important for the unde...

  7. Carbohydrates, Sugar, and Your Child

    Science.gov (United States)

    ... carbs are: simple carbohydrates (or simple sugars): including fructose, glucose, and lactose, which also are found in nutritious ... sugar, check the ingredients list for sugar, corn syrup, or other sweeteners, such as dextrose, fructose, honey, or molasses, to name just a few. ...

  8. Trophic Diversity of Plankton in the Epipelagic and Mesopelagic Layers of the Tropical and Equatorial Atlantic Determined with Stable Isotopes

    Directory of Open Access Journals (Sweden)

    Antonio Bode

    2018-06-01

    Full Text Available Plankton living in the deep ocean either migrate to the surface to feed or feed in situ on other organisms and detritus. Planktonic communities in the upper 800 m of the tropical and equatorial Atlantic were studied using the natural abundance of stable carbon and nitrogen isotopes to identify their food sources and trophic diversity. Seston and zooplankton (>200 µm samples were collected with Niskin bottles and MOCNESS nets, respectively, in the epipelagic (0–200 m, upper mesopelagic (200–500 m, and lower mesopelagic layers (500–800 m at 11 stations. Food sources for plankton in the productive zone influenced by the NW African upwelling and the Canary Current were different from those in the oligotrophic tropical and equatorial zones. In the latter, zooplankton collected during the night in the mesopelagic layers was enriched in heavy nitrogen isotopes relative to day samples, supporting the active migration of organisms from deep layers. Isotopic niches showed also zonal differences in size (largest in the north, mean trophic diversity (largest in the tropical zone, food sources, and the number of trophic levels (largest in the equatorial zone. The observed changes in niche size and overlap (up to 71% between the mesopelagic layers but <50% between the epipelagic and upper mesopelagic layers support the prevalence of in situ feeding at deep layers in tropical and equatorial zooplankton.

  9. Qualitative Carbohydrate Analysis using Alkaline Potassium ...

    Indian Academy of Sciences (India)

    IAS Admin

    CLASSROOM. 285. RESONANCE | March 2016. Qualitative Carbohydrate Analysis using Alkaline. Potassium Ferricyanide. Keywords. Alkaline potassium ferricyanide, qualitative ... Carbohydrates form a distinct class of organic compounds often .... Laboratory Techniques: A contemporary Approach, W B Saunders Com-.

  10. Carbohydrate Microarray on Glass: a Tool for Carbohydrate-Lectin Interactions

    NARCIS (Netherlands)

    Tetala, K.K.R.; Giesbers, M.; Visser, G.M.; Sudhölter, E.J.R.; Beek, van T.A.

    2007-01-01

    A simple method to immobilize carbohydrates on a glass surface to obtain a carbohydrate microarray is described. The array was used to study carbohydrate-lectin interactions. The glass surface was modified with aldehyde terminated linker groups of various chain lengths. Coupling of carbohydrates

  11. Disinfection efficiencies of sage and spearmint essential oils against planktonic and biofilm Staphylococcus aureus cells in comparison with sodium hypochlorite.

    Science.gov (United States)

    Vetas, Dimitrios; Dimitropoulou, Eleni; Mitropoulou, Gregoria; Kourkoutas, Yiannis; Giaouris, Efstathios

    2017-09-18

    Staphylococcus aureus causes human infections and foodborne intoxications. This study explored the potential antibacterial actions of sage and spearmint essential oils (EOs) against both its planktonic and biofilm cells, in comparison with sodium hypochlorite (NaOCl), a commonly applied chemical sanitizer. Initially, the minimum inhibitory and bactericidal concentrations (MICs, MBCs) of each plant mixture were determined against planktonic cultures, following growth at 30°C for 24h. Stationary phase planktonic bacteria were then individually exposed for 6min to either each EO (applied at 1-2×MBC; 2.5-5%), or NaOCl (250-450ppm). These were also left to form biofilms on 96-well polystyrene microplates, at 30°C for 96h, with medium renewal at 48h, in the presence of 10 different concentrations of each EO, expanding from sub- to super-inhibitory for planktonic growth, and the minimum biofilm inhibitory concentrations (MBICs; >90% inhibition) of each plant mixture were calculated. Formed biofilms were finally exposed for 6min to either each EO (applied at 2-6×MBC; 5-15%), or NaOCl (7500-25,000ppm; applied either alone or in combination with each EO at 5%). Results showed that both EOs presented MIC and MBC equal to 1.25 and 2.5%, respectively. As expected, their application at their MIC and above significantly inhibited biofilm formation, while spearmint EO was still able to cause this at ½ of its MIC, with MBICs equal to 1.25 and 0.63% for sage and spearmint EOs, respectively. Alarmingly, the application of both EOs at 1/8 to 1/16 of their MIC further increased biofilm formation. Regarding biofilm disinfection experiments, the individual application of each EO against the pre-established sessile communities resulted in log decrease ranges of 0.8-3logCFU/cm 2 , while in the case of NaOCl application (either alone or combined with each EO), the observed reductions never exceeded 1.7logCFU/cm 2 . These last results highlight the great antimicrobial recalcitrance of

  12. Seasonality in ocean microbial communities.

    Science.gov (United States)

    Giovannoni, Stephen J; Vergin, Kevin L

    2012-02-10

    Ocean warming occurs every year in seasonal cycles that can help us to understand long-term responses of plankton to climate change. Rhythmic seasonal patterns of microbial community turnover are revealed when high-resolution measurements of microbial plankton diversity are applied to samples collected in lengthy time series. Seasonal cycles in microbial plankton are complex, but the expansion of fixed ocean stations monitoring long-term change and the development of automated instrumentation are providing the time-series data needed to understand how these cycles vary across broad geographical scales. By accumulating data and using predictive modeling, we gain insights into changes that will occur as the ocean surface continues to warm and as the extent and duration of ocean stratification increase. These developments will enable marine scientists to predict changes in geochemical cycles mediated by microbial communities and to gauge their broader impacts.

  13. Zooplankton motile behavior: traits and trade-offs in planktonic copepods

    DEFF Research Database (Denmark)

    van Someren Gréve, Hans

    Research on planktonic copepod ecology is vital to understand the factors controlling marine food web dynamics since copepods are the major components of zooplankton communities and the main link between trophic levels in marine environments. Despite their taxonomic diversity, copepods share...... certain phenotypic characteristics, or ´traits´, that are essential in determining trophic interactions and fitness. One important characteristic that decisively influences organism interactions is behavior. Copepods display two distinct behavioral strategies in terms of motility: ´active´ (feeding...... differences between genders in feeding efficiency and predation risk. Finally, we also found that foraging activity decreased with increasing food availability, especially in active feeding strategies, resulting in a decrease in predation risk. Therefore, changes in behavior depending on food availability...

  14. 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.

  15. Planktonic rotifer assemblages of the Danube River at Budapest after the red sludge pollution in Hungary.

    Science.gov (United States)

    Schöll, Károly; Szövényi, Gergely

    2011-08-01

    In the autumn of 2010 an industrial red sludge spill occurred in Hungary. The toxic chemical waste with high alkalinity (pH 13.5) reached the Danube 2 days later, where no change was expected because of the high level of dilution. The planktonic rotifer assemblages of the Danube were investigated at Budapest during the contamination. The median of community density decreased from 500 ind. 100 L(-1) to zero, the species richness from 3.00 to 0.00, Shannon-Weaver diversity from 1.10 to 0.00 after the arrival of the contamination. The rotifer assemblages seemed to have recovered after 3 weeks, but the initial levels of diversity and density were not reached again.

  16. Limnology and plankton diversity of salt lakes from Transylvanian Basin (Romania: A review

    Directory of Open Access Journals (Sweden)

    Mircea Alexe

    2017-09-01

    Full Text Available In the present work, we review the current knowledge on genesis, limnology and biodiversity of salt lakes distributed around the inner contour of Eastern Carpathian arc (Transylvanian Basin, Central Romania. Transylvanian salt lakes formed on ancient halite (NaCl deposits following natural processes or quarrying activities.  Most of these lakes are located in eastern (Sovata area, southern (Ocna Sibiului, and western (Turda-Cojocna parts of the Transylvanian Basin, have small surfaces (0.1-4 ha, variable depths (2-100 m, are hypersaline (>10%, w/v, total salts, mainly NaCl and permanently stratified. As consequence of steady salinity/density gradient, heat entrapment below surface layer (i.e., heliothermy develops in several Transylvanian lakes. The physical and chemical water stratification is mirrored in the partition of plankton diversity. Lakes with less saline (2-10% salinity water layers appear to harbor halotolerant representatives of phyto- (e.g., marine native Picochlorum spp. and Synechococcus spp., zoo- (e.g., Moina salina, and bacterioplankton (e.g., Actinobacteria, Verrucomicobia, whereas halophilic plankton communities (e.g., green algae Dunaliella sp., brine shrimp Artemia sp., and members of Halobacteria class dominate in the oxic surface of hypersaline (>10% salinity lakes. Molecular approaches (e.g., PCR-DGGE, 16S rRNA gene-based clone libraries, and DNA metabarcoding showed that the O2-depleted bottom brines of deep meromictic Transylvanian lakes are inhabited by known extremely halophilic anaerobes (e.g. sulfate-reducing Delta-Proteobacteria, fermenting Clostridia, methanogenic and polymer-degrading archaea in addition to representatives of uncultured/unclassified prokaryotic lineages. Overall, the plankton communities thriving in saline Transylvanian lakes seem to drive full biogeochemical cycling of main elements. However, the trophic interactions (i.e., food web structure and energy flow as well as impact of human

  17. Carbohydrate Microarrays in Plant Science

    DEFF Research Database (Denmark)

    Fangel, Jonatan Ulrik; Pedersen, H.L.; Vidal-Melgosa, S.

    2012-01-01

    Almost all plant cells are surrounded by glycan-rich cell walls, which form much of the plant body and collectively are the largest source of biomass on earth. Plants use polysaccharides for support, defense, signaling, cell adhesion, and as energy storage, and many plant glycans are also important...... industrially and nutritionally. Understanding the biological roles of plant glycans and the effective exploitation of their useful properties requires a detailed understanding of their structures, occurrence, and molecular interactions. Microarray technology has revolutionized the massively high...... for plant research and can be used to map glycan populations across large numbers of samples to screen antibodies, carbohydrate binding proteins, and carbohydrate binding modules and to investigate enzyme activities....

  18. Community.

    Science.gov (United States)

    Grauer, Kit, Ed.

    1995-01-01

    Art in context of community is the theme of this newsletter. The theme is introduced in an editorial "Community-Enlarging the Definition" (Kit Grauer). Related articles include: (1) "The Children's Bridge is not Destroyed: Heart in the Middle of the World" (Emil Robert Tanay); (2) "Making Bridges: The Sock Doll…

  19. Limits to gene flow in a cosmopolitan marine planktonic diatom.

    Science.gov (United States)

    Casteleyn, Griet; Leliaert, Frederik; Backeljau, Thierry; Debeer, Ann-Eline; Kotaki, Yuichi; Rhodes, Lesley; Lundholm, Nina; Sabbe, Koen; Vyverman, Wim

    2010-07-20

    The role of geographic isolation in marine microbial speciation is hotly debated because of the high dispersal potential and large population sizes of planktonic microorganisms and the apparent lack of strong dispersal barriers in the open sea. Here, we show that gene flow between distant populations of the globally distributed, bloom-forming diatom species Pseudo-nitzschia pungens (clade I) is limited and follows a strong isolation by distance pattern. Furthermore, phylogenetic analysis implies that under appropriate geographic and environmental circumstances, like the pronounced climatic changes in the Pleistocene, population structuring may lead to speciation and hence may play an important role in diversification of marine planktonic microorganisms. A better understanding of the factors that control population structuring is thus essential to reveal the role of allopatric speciation in marine microorganisms.

  20. High motility reduces grazing mortality of planktonic bacteria

    DEFF Research Database (Denmark)

    Matz, Carsten; Jurgens, K.

    2005-01-01

    We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated...... size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 mum(3). Grazing mortality was lowest for cells of >0.5 mum(3) and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (less than or equal to0.1 mum......(3), >50 mum s(-1)) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing....

  1. Psd1 Effects on Candida albicans Planktonic Cells and Biofilms

    Directory of Open Access Journals (Sweden)

    Sónia Gonçalves

    2017-06-01

    Full Text Available Candida albicans is an important human pathogen, causing opportunistic infections. The adhesion of planktonic cells to a substrate is the first step for biofilm development. The antimicrobial peptide (AMP Psd1 is a defensin isolated from Pisum sativum seeds. We tested the effects of this AMP on C. albicans biofilms and planktonic cells, comparing its activity with amphotericin B and fluconazole. Three C. albicans variants were studied, one of them a mutant deficient in glucosylceramide synthase, conferring resistance to Psd1 antifungal action. Atomic force microscopy (AFM was used to assess morphological and biomechanical changes on fungal cells. Surface alterations, with membrane disruption and leakage of cellular contents, were observed. Cytometry assays and confocal microscopy imaging showed that Psd1 causes cell death, in a time and concentration-dependent manner. These results demonstrate Psd1 pleiotropic action against a relevant fungal human pathogen, suggesting its use as natural antimycotic agent.

  2. Dietary carbohydrates and triacylglycerol metabolism.

    Science.gov (United States)

    Roche, H M

    1999-02-01

    There is a growing body of scientific evidence which demonstrates that plasma triacylglycerol (TAG) concentration, especially in the postprandial state, is an important risk factor in relation to the development of CHD. Postprandial hypertriacylglycerolaemia is associated with a number of adverse metabolic risk factors, including the preponderance of small dense LDL, low HDL-cholesterol concentrations and elevated factor VII activity. Traditionally, a low-fat high-carbohydrate diet was used to prevent CHD because it effectively reduces plasma cholesterol concentrations, but this dietary regimen increases plasma TAG concentrations and reduces HDL-cholesterol concentrations. There is substantial epidemiological evidence which demonstrates that high plasma TAG and low plasma HDL concentrations are associated with an increased risk of CHD. Thus, there is reason for concern that the adverse effects of low-fat high-carbohydrate diets on TAG and HDL may counteract or negate the beneficial effect of reducing LDL-cholesterol concentrations. Although there have been no prospective studies to investigate whether reduced fat intake has an adverse effect on CHD, there is strong epidemiological evidence that reducing total fat intake is not protective against CHD. On the other hand, high-fat diets predispose to obesity, and central obesity adversely affects TAG metabolism. There is substantial evidence that in free-living situations low-fat high-carbohydrate diets lead to weight loss, which in turn will correct insulin resistance and plasma TAG metabolism. Clearly there is a need for prospective studies to resolve the issue as to whether low-fat high-carbohydrate diets play an adverse or beneficial role in relation to the development of CHD.

  3. Proteorhodopsin lateral gene transfer between marine planktonic Bacteria and Archaea

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Martinez, Asuncion; Mincer, Tracy J

    2006-01-01

    Planktonic Bacteria, Archaea and Eukarya reside and compete in the ocean's photic zone under the pervasive influence of light. Bacteria in this environment were recently shown to contain photoproteins called proteorhodopsins, thought to contribute to cellular energy metabolism by catalysing light...... phylogenetic distribution of proteorhodopsins reflects their significant light-dependent fitness contributions, which drive the photoprotein's lateral acquisition and retention, but constrain its dispersal to the photic zone....

  4. Localised mixing and heterogeneity in the plankton food web in a frontal region of the Sargasso Sea

    DEFF Research Database (Denmark)

    Richardson, Katherine; Bendtsen, Joøgen; Christensen, Jens Tang

    2014-01-01

    the diatom communities at 10 m and > 100 m (in the deep chlorophyll maximum, DCM) than in other parts of the frontal region. Thorpe displacements supported the hypothesis of elevated mixing intensities around these stations, as did vertical mixing rates inferred from stratification and vertical current shear...... influence the plankton food web, as indicated by elevated values/concentrations of (1) primary production, (2) variable fluorescence (F-v/F-m) and (3) total seston. In addition, the fraction of the total biomass of both copepods and nauplii found closest to the DCM in the frontal region correlated...

  5. Massive consumption of gelatinous plankton by Mediterranean apex predators.

    Directory of Open Access Journals (Sweden)

    Luis Cardona

    Full Text Available Stable isotopes of carbon and nitrogen were used to test the hypothesis that stomach content analysis has systematically overlooked the consumption of gelatinous zooplankton by pelagic mesopredators and apex predators. The results strongly supported a major role of gelatinous plankton in the diet of bluefin tuna (Thunnus thynnus, little tunny (Euthynnus alletteratus, spearfish (Tetrapturus belone and swordfish (Xiphias gladius. Loggerhead sea turtles (Caretta caretta in the oceanic stage and ocean sunfish (Mola mola also primarily relied on gelatinous zooplankton. In contrast, stable isotope ratios ruled out any relevant consumption of gelatinous plankton by bluefish (Pomatomus saltatrix, blue shark (Prionace glauca, leerfish (Lichia amia, bonito (Sarda sarda, striped dolphin (Stenella caerueloalba and loggerhead sea turtles (Caretta caretta in the neritic stage, all of which primarily relied on fish and squid. Fin whales (Balaenoptera physalus were confirmed as crustacean consumers. The ratios of stable isotopes in albacore (Thunnus alalunga, amberjack (Seriola dumerili, blue butterfish (Stromaeus fiatola, bullet tuna (Auxis rochei, dolphinfish (Coryphaena hyppurus, horse mackerel (Trachurus trachurus, mackerel (Scomber scombrus and pompano (Trachinotus ovatus were consistent with mixed diets revealed by stomach content analysis, including nekton and crustaceans, but the consumption of gelatinous plankton could not be ruled out completely. In conclusion, the jellyvorous guild in the Mediterranean integrates two specialists (ocean sunfish and loggerhead sea turtles in the oceanic stage and several opportunists (bluefin tuna, little tunny, spearfish, swordfish and, perhaps, blue butterfish, most of them with shrinking populations due to overfishing.

  6. [Research advances in ecological stoichiometry of marine plankton].

    Science.gov (United States)

    Chen, Lei; Li, Chao-Lun

    2014-10-01

    Ecological stoichiometry can be simply defined as: The biology of elements from molecules to the biosphere, which spans all levels of the environment and of the life. It's a new idea to build a unified theory and becomes an inevitable trend to develop the ecological science. Marine ecosystems, which contribute to 50% of the biosphere biomass, are the important component of the global biogeochemical cycles. Marine zooplankton plays an important role in the material circulation and energy flow of marine ecosystems and serves as a connecting link between the preceding and the following in a more precise understanding of the key elemental cycles. However, research on ecological stoichiometry of marine plankton is fragmentary and rare. This article summarized the ecological phenomena and mechanisms of limiting elements affecting marine plankton, the response of biochemical substances to nutrition limitation, and the food chain transmission and feedback of nutrition limitation. Meanwhile, we also put forward some perspectives for future research of ecological stoichiometry of plankton in China' s seas.

  7. A systematic study of chemogenomics of carbohydrates.

    Science.gov (United States)

    Gu, Jiangyong; Luo, Fang; Chen, Lirong; Yuan, Gu; Xu, Xiaojie

    2014-03-04

    Chemogenomics focuses on the interactions between biologically active molecules and protein targets for drug discovery. Carbohydrates are the most abundant compounds in natural products. Compared with other drugs, the carbohydrate drugs show weaker side effects. Searching for multi-target carbohydrate drugs can be regarded as a solution to improve therapeutic efficacy and safety. In this work, we collected 60 344 carbohydrates from the Universal Natural Products Database (UNPD) and explored the chemical space of carbohydrates by principal component analysis. We found that there is a large quantity of potential lead compounds among carbohydrates. Then we explored the potential of carbohydrates in drug discovery by using a network-based multi-target computational approach. All carbohydrates were docked to 2389 target proteins. The most potential carbohydrates for drug discovery and their indications were predicted based on a docking score-weighted prediction model. We also explored the interactions between carbohydrates and target proteins to find the pathological networks, potential drug candidates and new indications.

  8. Cats and Carbohydrates: The Carnivore Fantasy?

    Directory of Open Access Journals (Sweden)

    Adronie Verbrugghe

    2017-11-01

    Full Text Available The domestic cat’s wild ancestors are obligate carnivores that consume prey containing only minimal amounts of carbohydrates. Evolutionary events adapted the cat’s metabolism and physiology to this diet strictly composed of animal tissues and led to unique digestive and metabolic peculiarities of carbohydrate metabolism. The domestic cat still closely resembles its wild ancestor. Although the carnivore connection of domestic cats is well recognised, little is known about the precise nutrient profile to which the digestive physiology and metabolism of the cat have adapted throughout evolution. Moreover, studies show that domestic cats balance macronutrient intake by selecting low-carbohydrate foods. The fact that cats evolved consuming low-carbohydrate prey has led to speculations that high-carbohydrate diets could be detrimental for a cat’s health. More specifically, it has been suggested that excess carbohydrates could lead to feline obesity and diabetes mellitus. Additionally, the chances for remission of diabetes mellitus are higher in cats that consume a low-carbohydrate diet. This literature review will summarise current carbohydrate knowledge pertaining to digestion, absorption and metabolism of carbohydrates, food selection and macronutrient balancing in healthy, obese and diabetic cats, as well as the role of carbohydrates in prevention and treatment of obesity and diabetes mellitus.

  9. Historical changes in the ecosystem condition of a small mountain lake over the past 60 years as revealed by plankton remains and Daphnia ephippial carapaces stored in lake sediments.

    Directory of Open Access Journals (Sweden)

    Hajime Ohtsuki

    Full Text Available To examine if changes in species composition of a plankton community in the past due to anthropogenic activities can be clarified in lakes without any monitoring data, we analyzed genetically ephippial carapaces of Daphnia with plankton remains stored in the bottom sediments of Lake Hataya Ohunma in Japan. In the lake, abundance of most plankton remains in the sediments was limited and TP flux was at low levels (2-4 mg/m2/y before 1970. However TP flux increased two-fold during the period from 1980s to 1990 s. In parallel with this increase, abundance of most plankton remains increased although abundance of benthic testate amoebae's remains decreased, indicating that the lake trophic condition had changed from oligo- to mesotrophic for the past 60 years. According to cluster analysis, the stratigraphic sediments were divided into two periods with different features of the phytoplankton composition. Chronological comparison with events in the watershed suggested that eutrophication occurred because of an increase in visitors to the watershed and deposition of atmospheric dust. In this lake more than 50% of resting eggs produced by Daphnia over the past 60 years hatched. However, genetic analysis of the ephippial carapaces (remains showed that the Daphnia population was originally composed of D. dentifera but that D. galeata, or its hybrid with D. dentifera, invaded and increased the population density when the lake was eutrophied. Subsequently, large D. pulex established populations in the 1980s when largemouth bass were anonymously introduced. These results indicated that the Lake Hataya Ohunma plankton community underwent significant changes despite the fact that there were no notable changes in land cover or land use in the watershed. Since increases in atmospheric deposition and release of fish have occurred in many Japanese lakes, the changes in the plankton community described here may be widespread in these lakes.

  10. Carbohydrates

    Science.gov (United States)

    ... such as kidney beans, black beans, pinto beans, black-eyed peas, split peas, and garbanzo beans Starchy vegetables, such as potatoes, corn, green peas, and parsnips Whole grains, such as brown rice, oats, barley, and quinoa Refined grains, such as ...

  11. Carbohydrates

    Science.gov (United States)

    ... of the great nutrients. That's why your best bet is whole grain. Enriched products means some of ... Molasses Syrup and malt syrup If you are thinking about using a sugar substitute, you may wonder ...

  12. Efficacy of a novel antimicrobial peptide against periodontal pathogens in both planktonic and polymicrobial biofilm states.

    Science.gov (United States)

    Wang, Hong-Yan; Cheng, Jya-Wei; Yu, Hui-Yuan; Lin, Li; Chih, Ya-Han; Pan, Ya-Ping

    2015-10-01

    Streptococcus gordonii, Fusobacterium nucleatum and Porphyromonas gingivalis represent the early, middle and late colonizers of the bacterial accretion in dental plaque biofilms. These sessile communities constitute a protected mode of growth that promotes survival in a hostile environment. This study describes a novel and unrecognized role for a synthetic cationic antimicrobial peptide, Nal-P-113, which inhibits and kills periodontal bacteria in planktonic state, inhibits the formation of biofilms and eradicates polymicrobial biofilms. Nal-P-113 is also stable in saliva, serum and saline solution. At a concentration less than 320 μg/mL which is harmless to normal oral cells, Nal-P-113 can kill bacteria in planktonic state. At a concentration of antimicrobial peptide Nal-P-113 (1280 μg/mL) which only causes slight damages to normal oral cells is needed to kill bacteria in biofilm state. It is worth mentioning that this concentration of Nal-P-113 is harmless to rat oral mucosa compared to chlorhexidine. The mechanism of Nal-P-113 inhibiting and killing periodontal bacteria might rely on the abilities to permeabilize and/or to form pores within the cytoplasmic membranes, thus causes the death of bacteria. Here, we provided a novel and stable antimicrobial peptide with very low mammalian cytotoxicity, which can inhibit and kill periodontal bacteria in both planktonic and polymicrobial biofilm states. Nal-P-113 is a potent antimicrobial peptide with strong antimicrobial ability, improved deficiency compared with other antibacterial peptides, and remains stable in phosphate buffered saline, saliva, brain-heart infusion medium and bovine calf serum. Nal-P-113 exhibits a broad spectrum of bacteriocidal activity with excellent eradicating capability on oral pathogens and the respective biofilms. In this study, we used propidium iodide staining, scanning electron microscopy and transmission electron microscopy to confirm that Nal-P-113 can perforate plasmalemma thereby

  13. Plankton in the open Mediterranean Sea: a review

    Directory of Open Access Journals (Sweden)

    I. Siokou-Frangou

    2010-05-01

    Full Text Available We present an overview of the plankton studies conducted during the last 25 years in the epipelagic offshore waters of the Mediterranean Sea. This quasi-enclosed sea is characterized by a rich and complex physical dynamics with distinctive traits, especially in regard to the thermohaline circulation. Recent investigations have basically confirmed the long-recognised oligotrophic nature of this sea, which increases along both the west-east and the north-south directions. Nutrient availability is low, especially for phosphorous (N:P up to 60, though this limitation may be buffered by inputs from highly populated coasts and from the atmosphere. Phytoplankton biomass, as chl a, generally displays low values (less than 0.2 μg chl a l−1 over large areas, with a modest late winter increase. A large bloom (up to 3 μg l−1 is observed throughout the late winter and spring exclusively in the NW area. Relatively high biomass values are recorded in fronts and cyclonic gyres. A deep chlorophyll maximum is a permanent feature for the whole basin, except during the late winter mixing. It is found at increasingly greater depths ranging from 30 m in the Alboran Sea to 120 m in the easternmost Levantine basin. Primary production reveals a west-east decreasing trend and ranges between 59 and 150 g C m−2 y−1 (in situ measurements. Overall, the basin is largely dominated by small autotrophs, microheterotrophs and egg-carrying copepod species. The microorganisms (phytoplankton, viruses, bacteria, flagellates and ciliates and zooplankton components reveal a considerable diversity and variability over spatial and temporal scales, although the latter is poorly studied. Examples are the wide diversity of dinoflagellates and coccolithophores, the multifarious role of diatoms or picoeukaryotes, and the distinct seasonal or spatial patterns of the species-rich copepod genera or families which dominate the

  14. Modelling the competition of planktonic and sessile aerobic heterotrophs for complementary nutrients in biofilm reactor.

    Science.gov (United States)

    Lu, T; Saikaly, P E; Oerther, D B

    2007-01-01

    A comprehensive, simplified microbial biofilm model was developed to evaluate the impact of bioreactor operating parameters on changes in microbial population abundance. Biofilm simulations were conducted using three special cases: fully penetrated, internal mass transfer resistance and external mass transfer resistance. The results of model simulations showed that for certain operating conditions, competition for growth limiting nutrients generated oscillations in the abundance of planktonic and sessile microbial populations. These oscillations resulted in the violation of the competitive exclusion principle where the number of microbial populations was greater than the number of growth limiting nutrients. However, the operating conditions which impacted microbial community diversity were different for the three special cases. Comparing the results of model simulations for dispersed-growth, biofilms and bioflocs showed that oscillations and microbial community diversity were a function of competition as well as other key features of the ecosystem. The significance of the current study is that it is the first to examine competition as a mechanism for controlling microbial community diversity in biofilm reactors.

  15. Distribusi Spasial Dan Struktur Komunitas Plankton Di Daerah Teluk Penerusan, Kabupaten Buleleng

    Directory of Open Access Journals (Sweden)

    Ni Made Dewi Damayanti

    2017-06-01

    Full Text Available Research spatial distribution and community structure of plankton in the Penerusan bay has been done on 22 February 2016.Plankton samples were taken at 17 stations using the Horizontal haul. The results obtained by the group of phytoplankton of the most widely found are from class Bacillariophyceae with the abundance of species composition percentage of 77% and the group most zooplankton were found came from class Maxillopoda with the percentage of the species composition of 85%. Highest abundance of phytoplankton found in abundance station 5, while the highest abundance of zooplankton found in abundance station 4. Index values diversity, uniformity and dominance of phytoplankton that is 1,06, 0.40 and 0.11 while the index value of diversity, uniformity and dominance zooplankton are 0.52,0.40 and 0.34. Results of the spatial distribution of phytoplankton abundance scattered in the middle of the bay towards the outside while the spatial distribution of zooplankton abundance spread from the south of the bay towards the middle of the bay and to the north of the bay Forwarding. Water quality in Penerusan Bay of physicists chemical parameters such as temperature obtained ranged from 31.1to 32,5 0C, average brightness obtained 87 %, turbidity obtained ranges between 0,73 to 2.62 ntu, dissolved oxygen (DO obtained ranged from 6 to 8.3 mg/l , the degree of acidity (pH obtained ranged from 7.17 to 8.04, salinity obtained ranged from 31-35 ppt, nitrate values obtained ranged from 0.60 to 1.83 mg/l and phosphate values obtained ranged from 0.10 to 0.78 mg/l.

  16. Spatiotemporal Distribution and Assemblages of Planktonic Fungi in the Coastal Waters of the Bohai Sea

    Directory of Open Access Journals (Sweden)

    Yaqiong Wang

    2018-03-01

    Full Text Available Fungi play a critical role in the nutrient cycling and ecological function in terrestrial and freshwater ecosystems. Yet, many ecological aspects of their counterparts in coastal ecosystems remain largely elusive. Using high-throughput sequencing, quantitative PCR, and environmental data analyses, we studied the spatiotemporal changes in the abundance and diversity of planktonic fungi and their abiotic and biotic interactions in the coastal waters of three transects along the Bohai Sea. A total of 4362 ITS OTUs were identified and more than 60% of which were unclassified Fungi. Of the classified OTUs three major fungal phyla, Ascomycota, Basidiomycota, and Chytridiomycota were predominant with episodic low dominance phyla Cryptomycota and Mucoromycota (Mortierellales. The estimated average Fungi-specific 18S rRNA gene qPCR abundances varied within 4.28 × 106 and 1.13 × 107copies/L with significantly (P < 0.05 different abundances among the transects suggesting potential influence of the different riverine inputs. The spatiotemporal changes in the OTU abundance of Ascomycota and Basidiomycota phyla coincided significantly (P < 0.05 with nutrients traced to riverine inputs and phytoplankton detritus. Among the eight major fungal orders, the abundance of Hypocreales varied significantly (P < 0.01 across months while Capnodiales, Pleosporales, Eurotiales, and Sporidiobolales varied significantly (P < 0.05 across transects. In addition, our results likely suggest a tripartite interaction model for the association within members of Cryptomycota (hyperparasites, Chytridiomycota (both parasites and saprotrophs, and phytoplankton in the coastal waters. The fungal network featured several hubs and keystone OTUs besides the display of cooperative and competitive relationship within OTUs. These results support the notion that planktonic fungi, hitherto mostly undescribed, play diverse ecological roles in marine habitats and further outline niche processes

  17. Large Plankton Enhance Heterotrophy Under Experimental Warming in a Temperate Coastal Ecosystem

    KAUST Repository

    Huete-Stauffer, Tamara Megan

    2017-12-15

    Microbes are key players in oceanic carbon fluxes. Temperate ecosystems are seasonally variable and thus suitable for testing the effect of warming on microbial carbon fluxes at contrasting oceanographic conditions. In four experiments conducted in February, April, August and October 2013 in coastal NE Atlantic waters, we monitored microbial plankton stocks and daily rates of primary production, bacterial heterotrophic production and respiration at in situ temperature and at 2 and 4°C over ambient values during 4-day incubations. Ambient total primary production (TPP) exceeded total community respiration (< 200 µm, TR) in winter and fall but not in spring and summer. The bacterial contribution to ecosystem carbon fluxes was low, with bacterial production representing on average 6.9 ± 3.2% of TPP and bacterial respiration (between 0.8 and 0.2 µm) contributing on average 35 ± 7% to TR. Warming did not result in a uniform increase in the variables considered, and most significant effects were found only for the 4°C increase. In the summer and fall experiments, under warm and nutrient-deficient conditions, the net TPP/TR ratio decreased by 39 and 34% in the 4°C treatment, mainly due to the increase in respiration of large organisms rather than bacteria. Our results indicate that the interaction of temperature and substrate availability in determining microbial carbon fluxes has a strong seasonal component in temperate planktonic ecosystems, with temperature having a more pronounced effect and generating a shift toward net heterotrophy under more oligotrophic conditions as found in summer and early fall.

  18. Spatial and temporal variability of planktonic archaeal abundance in the Humboldt Current System off Chile

    Science.gov (United States)

    Quiñones, Renato A.; Levipan, Héctor A.; Urrutia, Homero

    2009-07-01

    The latest advances in the field of microbial ecology have shown that planktonic Archaea are one of the most abundant unicellular microorganisms of the oceans. However, no information is available on the contribution this group makes to the prokaryote assemblages that inhabit the eastern South Pacific Ocean. Here, we describe the relative abundance and vertical distribution of planktonic Archaea off northern and central-southern Chile. Data come from several cruises and a 45-month time series at a station located on the shelf off central-southern Chile. Both the taxonomic composition of the prokaryote community and its relative abundance were determined using quantitative dot blot 16S-rRNA hybridizations. Total Archaea in central-southern Chile made up 6-87% of the prokaryote rRNA in the water column and did not present evidence of any seasonal pattern. Crenarchaea were the most abundant archaeal group at this site and were significantly associated with the ammonium concentration ( r2=0.16, p=0.0003, n=80). Archaeal abundance in the time series was usually greater in the deeper layer (>50 m), with contributions reaching up to ˜90% of the prokaryote rRNA on certain occasions, and decreasing towards the surface. Important increments in the relative abundance of total Archaea were observed on given dates at the surface of the time-series station off central-southern Chile. Off northern Chile, total Archaea normally contributed from ˜10% to 50% of the prokaryote rRNA found between 10 and 1000 m, and were generally important in the mesopelagic realm. Our results indicate that Archaea constitute an important fraction of the prokaryote assemblage in the water column of the Humboldt Current System, especially in the oxygen minimum zone.

  19. The effects of carbohydrate variation in isocaloric diets on glycogenolysis and gluconeogenesis in healthy men

    NARCIS (Netherlands)

    Bisschop, P. H.; Pereira Arias, A. M.; Ackermans, M. T.; Endert, E.; Pijl, H.; Kuipers, F.; Meijer, A. J.; Sauerwein, H. P.; Romijn, J. A.

    2000-01-01

    To evaluate the effect of dietary carbohydrate content on postabsorptive glucose metabolism, we quantified gluconeogenesis and glycogenolysis after 11 days of high carbohydrate (85% carbohydrate), control (44% carbohydrate), and very low carbohydrate (2% carbohydrate) diets in six healthy men. Diets

  20. The effects of carbohydrate variation in isocaloric diets on glycogenolysis and gluconeogenesis in healthy men

    NARCIS (Netherlands)

    Bisschop, PH; Arias, AMP; Ackermans, MT; Endert, E; Pijl, H; Kuipers, F; Meijer, AJ; Sauerwein, HP; Romijn, JA

    To evaluate the effect of dietary carbohydrate content on postabsorptive glucose metabolism, we quantified gluconeogenesis and glycogenolysis after 11 days of high carbohydrate (85% carbohydrate), control (44% carbohydrate), and very low carbohydrate (2% carbohydrate) diets in six healthy men. Diets

  1. The comparative geochemistries of lignins and carbohydrates in an anoxic fjord

    Science.gov (United States)

    Hamilton, Susan E.; Hedges, John I.

    1988-01-01

    A reducing, varved sediment core and monthly (May-September) plankton and sediment trap samples from Saanich Inlet, B.C., Canada, were analyzed for their elemental, lignin and neutral sugar compositions. Total yields of lignin-derived phenols from both the sediment trap and core samples indicated less than 15% and 30%, respectively, of chemically recognizable vascular plant remains, derived predominantly from gymnosperm wood and nonwoody angiosperm tissues. The elevated vanillyl and syringyl acid/aldehyde ratios of this material compared to fresh plant material indicated that it suffered mild aerobic decomposition prior to introduction to the Inlet. Most of the remaining particular organic material was nitrogen-rich, carbohydrate-poor and apparently plankton-derived. Organic carbon, total nitrogen, and total neutral sugars and lignin phenols all exhibited decreasing concentrations with depth in a region of uniform varving (upper 15 cm) in the sediment core. All profiles exhibited particularly steep concentration decreases within the top 2 cm of sediment. First-order decay constants for all four chemical categories within the upper 14 cm of the core ranged between 0.1-0.2 yr -1. Neutral sugars were consistently the most reactive chemical class, accounting for roughly 15% of the total organic carbon turnover. Although lignin appeared to be degraded within the sediment core, this degradation was nonselective for different lignin types and did not lead to increased acid/aldehyde ratios as occur during aerobic lignin decomposition. Comparisons of the yields of individual neutral sugars from the sediment and sediment trap samples to those expected from the vascular plant component alone indicated that the vascular plant debris in the upper portion of the sediment core had lost a portion of its initial glucose, lyxose, and mannose. In contrast, rhamnose and fucose were produced by all samples in large excess of total yields expected for chemically intact vascular plant

  2. KOEFISIEN SAPROBIK PLANKTON DI PERAIRAN EMBUNG UNIVERSITAS NEGERI SEMARANG

    Directory of Open Access Journals (Sweden)

    AS Awaludin

    2016-04-01

    Full Text Available Embung Universitas Negeri Semarang dibangun dengan tujuan sebagai tempat penampungan air hujan dan penyerapan air di Universitas Negeri Semarang dan mempunyai kapasitas penampungan air 5.000 m3. Keberadaan embung tersebut menciptakan suatu ekosistem baru yaitu tempat hidup ikan-ikan di dalamnya. Saprobitas perairan digunakan untuk mengetahui keadaan kualitas air yang diakibatkan adanya penambahan bahan organik dalam suatu  perairan yang biasanya indikatornya adalah jumlah dan susunan spesies dari organisme di dalam perairan tersebut. Plankton dapat digunakan sebagai bioindikator perairan karena memiliki tingkat kepekaan tinggi terhadap adanya pencemaran. Penelitian ini menggunakan rancangan eksplorasi dengan metode survai, dimana penetapan stasiun pengambilan sampel dengan purposive sampling. Penempatan stasiun didasarkan atas perkiraan beban pencemar dan aktivitas yang terdapat di sepanjang aliran dari (stasiun satu sampai sembilan, pengambilan sampel dilakukan sebanyak 3 kali dengan selang waktu 2 minggu. Data dalam penelitian ini adalah data kuantitatif berupa jumlah jenis spesies plankton yang ditemukan pada penelitian ini kemudian diinterpretasikan pada tabel hubungan antara koefisien saprobitas perairan dengan tingkat pencemaran perairan. Berdasarkan perhitungan dan analisis nilai koefisien saprobik dari stasiun satu sampai sampai sembilan didapatkan nilai koefisien saprobik plankton berkisar antara -0,4 s/d 0,9. Berdasarkan kriteria tingkat pencemaran menunjukkan bahwa Embung Universitas Negeri Semarang berada dalam kondisi tercemar ringan sampai dengan sedang.Universitas Negeri Semarang Reservoir was constructed for the purpose as rain water reservoirs and water absorption in Universitas Negeri Semarang and has a water storage capacity of 5,000 cubic meters. The existence of such ponds are creating a new ecosystem where fish live in it. Saprobic waters are used to determine the state of water quality resulting from the addition of

  3. A Model of the Dynamics of Plankton Patchiness

    Directory of Open Access Journals (Sweden)

    Wolfgang Ebenhöh

    1980-04-01

    Full Text Available A mathematical model of the dynamics of plankton patchiness in the intermediate scale (1 km-10 km was developed. Mechanisms that may be important in the creation and destruction of patches were selected and modelled. Such mechanisms are: horizontal turbulent diffusion, noise in the vertical turbulence, vertical migration of the zooplankton combined with a velocity profile and consumption of zooplankton by fish in schools. Patchiness is described by thc usc of the moments of density distributions, coherence lengths and correlations of phytoplankton and zooplankton. These parameters are investigated as functions of time and, also, for their dependence on the parameters of the patch creation mechanisms.

  4. Scaling of fecundity, growth and development in marine planktonic copepods

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Sabatini, M.

    1995-01-01

    We compiled information from the literature on female and egg sizes and maximum egg production, growth and developmental rates in marine planktonic copepods. While specific growth and developmental rates are invariant with body mass, weight- specific fecundity scales with female body mass(-0...... to 50% and have weight-specific fecundities that are 2.5 times and egg production rates that are 7.5 times those of the former, Nauplii develop faster (by a factor of 2) but grow slower (by 20 to 40%) than copepodites in both spawning types. The main demographic implications of these findings are (1...

  5. Physiological aspects of energy metabolism and gastrointestinal effects of carbohydrates.

    Science.gov (United States)

    Elia, M; Cummings, J H

    2007-12-01

    The energy values of carbohydrates continue to be debated. This is because of the use of different energy systems, for example, combustible, digestible, metabolizable, and so on. Furthermore, ingested macronutrients may not be fully available to tissues, and the tissues themselves may not be able fully to oxidize substrates made available to them. Therefore, for certain carbohydrates, the discrepancies between combustible energy (cEI), digestible energy (DE), metabolizable energy (ME) and net metabolizable energy (NME) may be considerable. Three food energy systems are in use in food tables and for food labelling in different world regions based on selective interpretation of the digestive physiology and metabolism of food carbohydrates. This is clearly unsatisfactory and confusing to the consumer. While it has been suggested that an enormous amount of work would have to be undertaken to change the current ME system into an NME system, the additional changes may not be as great as anticipated. In experimental work, carbohydrate is high in the macronutrient hierarchy of satiation. However, studies of eating behaviour indicate that it does not unconditionally depend on the oxidation of one nutrient, and argue against the operation of a simple carbohydrate oxidation or storage model of feeding behaviour to the exclusion of other macronutrients. The site, rate and extent of carbohydrate digestion in, and absorption from the gut are key to understanding the many roles of carbohydrate, although the concept of digestibility has different meanings. Within the nutrition community, the characteristic patterns of digestion that occur in the small (upper) vs large (lower) bowel are known to impact in contrasting ways on metabolism, while in the discussion of the energy value of foods, digestibility is defined as the proportion of combustible energy that is absorbed over the entire length of the gastrointestinal tract. Carbohydrates that reach the large bowel are fermented to

  6. Complex carbohydrate utilization by the healthy human microbiome.

    Directory of Open Access Journals (Sweden)

    Brandi L Cantarel

    Full Text Available The various ecological habitats in the human body provide microbes a wide array of nutrient sources and survival challenges. Advances in technology such as DNA sequencing have allowed a deeper perspective into the molecular function of the human microbiota than has been achievable in the past. Here we aimed to examine the enzymes that cleave complex carbohydrates (CAZymes in the human microbiome in order to determine (i whether the CAZyme profiles of bacterial genomes are more similar within body sites or bacterial families and (ii the sugar degradation and utilization capabilities of microbial communities inhabiting various human habitats. Upon examination of 493 bacterial references genomes from 12 human habitats, we found that sugar degradation capabilities of taxa are more similar to others in the same bacterial family than to those inhabiting the same habitat. Yet, the analysis of 520 metagenomic samples from five major body sites show that even when the community composition varies the CAZyme profiles are very similar within a body site, suggesting that the observed functional profile and microbial habitation have adapted to the local carbohydrate composition. When broad sugar utilization was compared within the five major body sites, the gastrointestinal track contained the highest potential for total sugar degradation, while dextran and peptidoglycan degradation were highest in oral and vaginal sites respectively. Our analysis suggests that the carbohydrate composition of each body site has a profound influence and probably constitutes one of the major driving forces that shapes the community composition and therefore the CAZyme profile of the local microbial communities, which in turn reflects the microbiome fitness to a body site.

  7. Comparative study on composition and abundance of major planktons and physico-chemical characteristics among two ponds and Lake Tana, Ethiopia

    Directory of Open Access Journals (Sweden)

    Wondie Zelalem Amanu

    2015-11-01

    Full Text Available Objective: To evaluate the difference in physico-chemical characteristics, composition and abundance of plankton communities owing to the supplementary feed added in fish ponds as compared to Lake Tana. Methods: Physico-chemical and biological data of plankton were collected from 3 studied sites from November 2008 to October 2009. Data were compared using One-way ANOVA to see the difference among sites. Diversity indices such as Margalef's index, Shannon-Wiener index, and evenness index were employed to describe the distribution of plankton community among the studied sites. Results: The pH value was remarkably higher in ponds water. However, conductivity and total dissolved solids were the highest in lake water. Nitrate concentration was relatively high in ponds. Zooplankton species richness was higher in lake water than ponds. The lake also had the highest mean value of both Shannon-Wiener index and evenness index in phytoplankton. Conclusions: The results revealed that the supplementary feed added to each pond had influence on nutrient content which enhanced algal biomass and productivity of the ponds. However, the pond water has to be regularly refreshed to control eutrophication.

  8. Distribution of planktonic foraminifera in waters of the submarine coral banks in southeast Arabian Sea during winter

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Balasubramanian, T.

    Twentyfive species of planktonic foraminifera are recorded from 36 plankton tows collected from waters of the submerged coral banks- Bassas de Pedro, Sesostris and Cora Divh-located at northern end of the Laccadive group of islands in southeastern...

  9. Wood adhesives containing proteins and carbohydrates

    Science.gov (United States)

    In recent years there has been resurgent interest in using biopolymers as sustainable and environmentally friendly ingredients in wood adhesive formulations. Among them, proteins and carbohydrates are the most commonly used. In this chapter, an overview is given of protein-based and carbohydrate-...

  10. Conversion of carbohydrates to levulinic acid esters

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to the field of converting carbohydrates into levulinic acid, a platform chemical for many chemical end products. More specifically the invention relates to a method for converting carbohydrates such as mono-, di- or polysaccharides, obtained from for example biomass...

  11. Vacuum ultraviolet photoionization of carbohydrates and nucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Joong-Won, E-mail: jshin@govst.edu [Division of Science, Governors State University, University Park, Illinois 60484-0975 (United States); Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872 (United States); Bernstein, Elliot R., E-mail: erb@lamar.colostate.edu [Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872 (United States)

    2014-01-28

    Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5{sup ′}-monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate, rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C–C and C–O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results.

  12. Vacuum ultraviolet photoionization of carbohydrates and nucleotides

    International Nuclear Information System (INIS)

    Shin, Joong-Won; Bernstein, Elliot R.

    2014-01-01

    Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5 ′ -monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate, rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C–C and C–O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results

  13. Carbohydrate epitopes on Haemonchus contortus antigens

    NARCIS (Netherlands)

    Schallig, H. D.; van Leeuwen, M. A.

    1996-01-01

    Extracts of infective larvae and adults of the trichostrongylid Haemonchus contortus were studied for the presence of carbohydrate moieties. Several different lectin-binding sites were demonstrated in both stages using a panel of nine lectins. The carbohydrate specificity of the lectins used

  14. Determining a carbohydrate profile for Hansenula polymorpha

    Science.gov (United States)

    Petersen, G. R.

    1985-01-01

    The determination of the levels of carbohydrates in the yeast Hansenula polymorpha required the development of new analytical procedures. Existing fractionation and analytical methods were adapted to deal with the problems involved with the lysis of whole cells. Using these new procedures, the complete carbohydrate profiles of H. polymorpha and selected mutant strains were determined and shown to correlate favourably with previously published results.

  15. Total dissolved carbohydrate in Mahi river estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Rokade, M.A.; Zingde, M.D.

    Total dissolved carbohydrate varied from 4.37-15 mg l-1 and 3.71-15.95 mg l-1 in the surface and bottom samples respectively. Highest concentration of carbohydrate was observed at station 1 which decreased downward upto Station 6 which showed...

  16. Characterization of carbohydrate fractions and fermentation quality ...

    African Journals Online (AJOL)

    This experiment was carried out to evaluate the effects of adding fast-sile (FS), previous fermented juice (PFJ), sucrose (S) or fast-sile + sucrose (FS + S) on the fermentation characteristics and carbohydrates fractions of alfalfa silages by the Cornell net carbohydrates and proteins systems (CNCPS). Silages quality were well ...

  17. Carbohydrate clearance receptors in transfusion medicine

    DEFF Research Database (Denmark)

    Sørensen, Anne Louise Tølbøll; Clausen, Henrik; Wandall, Hans H

    2012-01-01

    Complex carbohydrates play important functions for circulation of proteins and cells. They provide protective shields and refraction from non-specific interactions with negative charges from sialic acids to enhance circulatory half-life. For recombinant protein therapeutics carbohydrates are espe...

  18. Comparative transcriptome analysis of biofilm and planktonic cells of Bacillus cereus ATCC 14579

    NARCIS (Netherlands)

    Wijman, Janneke; Mols, M.; Tempelaars, Marcel; Abee, Tjakko

    2015-01-01

    Planktonic and biofilm cells of Bacillus cereus ATCC 14579 and ATCC 10987 were studied using microscopy and transcriptome analysis. By microscopy, clear differences could be observed between biofilm and planktonic cells as well as between the two strains. By using hierarchical clustering of the

  19. Comparative transcriptome analysis of biofilm and planktonic cells of Bacillus cereus ATCC 10987

    NARCIS (Netherlands)

    Wijman, Janneke; Mols, M.; Tempelaars, Marcel; Abee, Tjakko

    2015-01-01

    Planktonic and biofilm cells of Bacillus cereus ATCC 14579 and ATCC 10987 were studied using microscopy and transcriptome analysis. By microscopy, clear differences could be observed between biofilm and planktonic cells as well as between the two strains. By using hierarchical clustering of the

  20. Daytime pelagic schooling behaviour and relationships with plankton patch distribution in the Sicily Strait (Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    B. Patti

    2011-06-01

    Full Text Available In this study, hydroacoustic data collected with a scientific echosounder working at two frequencies (38 and 120 kHz over the continental shelf off the southern Sicilian coast were used in order to investigate the relationship between fish schools and plankton patches. Specifically, image analysis algorithms were applied to raw echograms in order to detect and characterise pelagic fish schools and plankton aggregations, considered as a proxy of food availability. The relationship was first investigated using estimated total plankton biomass over the whole water column and, second, by dividing the study area into three sub-regions and further distinguishing plankton patches between the surface and the bottom. In the relatively lower plankton abundance areas of Zone 1 (northern sector of the study area, results showed an inverse relationship between the biomass (and density of fish schools and the biomass of co-occurring plankton patches located close to the bottom. Instead, over the Sicilian-Maltese shelf (Zone 3, characterised by higher plankton abundances, a direct relationship was found when using plankton data from the whole water column. The observed difference between Zones 1 and 3 is probably due to diverse dominant fish species in the two sub-regions.

  1. Antimicrobial activity of vanadium chloroperoxidase on planktonic Streptococcus mutans cells and Streptococcus mutans biofilms

    NARCIS (Netherlands)

    Hoogenkamp, M.A.; Crielaard, W.; ten Cate, J.M.; Wever, R.; Hartog, A.F.; Renirie, R.

    2009-01-01

    The aim of this study was to investigate the antimicrobial activity of vanadium chloroperoxidase (VCPO) reaction products on planktonic and biofilm cellsof Streptococcus mutans C180-2. Planktonic and biofilm cells were incubated in a buffered reaction mixture containing VCPO, halide (either chloride

  2. The predictive skill of species distribution models for plankton in a changing climate

    DEFF Research Database (Denmark)

    Brun, Philipp Georg; Kiørboe, Thomas; Licandro, Priscilla

    2016-01-01

    Statistical species distribution models (SDMs) are increasingly used to project spatial relocations of marine taxa under future climate change scenarios. However, tests of their predictive skill in the real-world are rare. Here, we use data from the Continuous Plankton Recorder program, one...... null models, is essential to assess the robustness of projections of marine planktonic species under climate change...

  3. Covariance among North Sea nutrient and climate drivers: consequences for plankton dynamics.

    NARCIS (Netherlands)

    McQuatters-Gollop, A.; Vermaat, J.E.

    2011-01-01

    Regime shift and principal component analysis of a spatially disaggregated database capturing time-series of climatic, nutrient and plankton variables in the North Sea revealed considerable covariance between groups of ecosystem indicators. Plankton and climate time-series span the period 1958-2003,

  4. Living planktonic foraminifera during the late summer monsoon period in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.; Mohan, R.; Muralinath, A.S.

    with deepening of the mixed layer, since this species preferentially dwells in nutrient-rich upwelling waters. The population density of planktonic foraminifera ranges between 31 and 185 specimens per 10@u-3@@m@u3@@. The low absolute numbers of planktonic...

  5. Mining big data sets of plankton images: a zero-shot learning approach to retrieve labels without training data

    Science.gov (United States)

    Orenstein, E. C.; Morgado, P. M.; Peacock, E.; Sosik, H. M.; Jaffe, J. S.

    2016-02-01

    Technological advances in instrumentation and computing have allowed oceanographers to develop imaging systems capable of collecting extremely large data sets. With the advent of in situ plankton imaging systems, scientists must now commonly deal with "big data" sets containing tens of millions of samples spanning hundreds of classes, making manual classification untenable. Automated annotation methods are now considered to be the bottleneck between collection and interpretation. Typically, such classifiers learn to approximate a function that predicts a predefined set of classes for which a considerable amount of labeled training data is available. The requirement that the training data span all the classes of concern is problematic for plankton imaging systems since they sample such diverse, rapidly changing populations. These data sets may contain relatively rare, sparsely distributed, taxa that will not have associated training data; a classifier trained on a limited set of classes will miss these samples. The computer vision community, leveraging advances in Convolutional Neural Networks (CNNs), has recently attempted to tackle such problems using "zero-shot" object categorization methods. Under a zero-shot framework, a classifier is trained to map samples onto a set of attributes rather than a class label. These attributes can include visual and non-visual information such as what an organism is made out of, where it is distributed globally, or how it reproduces. A second stage classifier is then used to extrapolate a class. In this work, we demonstrate a zero-shot classifier, implemented with a CNN, to retrieve out-of-training-set labels from images. This method is applied to data from two continuously imaging, moored instruments: the Scripps Plankton Camera System (SPCS) and the Imaging FlowCytobot (IFCB). Results from simulated deployment scenarios indicate zero-shot classifiers could be successful at recovering samples of rare taxa in image sets. This

  6. SAR11 Bacteria: The Most Abundant Plankton in the Oceans.

    Science.gov (United States)

    Giovannoni, Stephen J

    2017-01-03

    SAR11 is a group of small, carbon-oxidizing bacteria that reach a global estimated population size of 2.4×10 28 cells-approximately 25% of all plankton. They are found throughout the oceans but reach their largest numbers in stratified, oligotrophic gyres, which are an expanding habitat in the warming oceans. SAR11 likely had a Precambrian origin and, over geological time, evolved into the niche of harvesting labile, low-molecular-weight dissolved organic matter (DOM). SAR11 cells are minimal in size and complexity, a phenomenon known as streamlining that is thought to benefit them by lowering the material costs of replication and maximizing transport functions that are essential to competition at ultralow nutrient concentrations. One of the surprises in SAR11 metabolism is their ability to both oxidize and produce a variety of volatile organic compounds that can diffuse into the atmosphere. SAR11 cells divide slowly and lack many forms of regulation commonly used by bacterial cells to adjust to changing environmental conditions. As a result of genome reduction, they require an unusual range of nutrients, which leads to complex biochemical interactions with other plankton. The study of SAR11 is providing insight into the biogeochemistry of labile DOM and is affecting microbiology beyond marine science by providing a model for understanding the evolution and function of streamlined cells.

  7. Ecology of planktonic foraminifera and their symbiotic algae

    International Nuclear Information System (INIS)

    Gastrich, M.D.

    1986-01-01

    Two types of symbiotic algae occurred abundantly and persistently in the cytoplasm of several species of planktonic Foraminifera over a ten year period in different tropical and subtropical areas of the North Atlantic Ocean. These planktonic Foraminifera host species consistently harbored either dinoflagellates or a newly described minute coccoid algal type. There appeared to be a specific host-symbiont relationship in these species regardless of year, season or geographic locality. The larger ovoid dinoflagellates (Pyrrhophycophyta) occur in the spinose species Globigerinoides ruber, Globigerinoides sacculifer, G. conglobatus and Orbulina universa. The smaller alga, from 1.5 to 3.5 um in diameter, occurs in one spinose species Globigerinella aequilateralis and also in the non-spinose species Globigerinita glutinata, Globoquadrina dutertrei, Globorotalia menardii, Globorotalia cristata, Globorotalia inflata, Candeina nitida, in various juvenile specimens and at all seasons except the winter months in Pulleniatina obliquiloculata and Globorotalial hirsuta. Controlled laboratory studies indicated a significant C incorporation into the host cytoplasm and inorganic calcium carbonate test of Globigerinoides ruber. During incubation for up to two hours, the 14 C uptake into the cytoplasm and test in the light was significantly greater than uptake in the dark by living specimens or by dead foraminifers. There appears to be light-enhanced uptake of 14 C into the test with dinoflagellate photosynthesis contributing to host calcification. In culture, symbiotic algae were observed to survive for the duration of the lifespan of their hosts

  8. Salinity controls on Na incorporation in Red Sea planktonic foraminifera

    Science.gov (United States)

    Mezger, E. M.; de Nooijer, L. J.; Boer, W.; Brummer, G. J. A.; Reichart, G. J.

    2016-12-01

    Whereas several well-established proxies are available for reconstructing past temperatures, salinity remains challenging to assess. Reconstructions based on the combination of (in)organic temperature proxies and foraminiferal stable oxygen isotopes result in relatively large uncertainties, which may be reduced by application of a direct salinity proxy. Cultured benthic and planktonic foraminifera showed that Na incorporation in foraminiferal shell calcite provides a potential independent proxy for salinity. Here we present the first field calibration of such a potential proxy. Living planktonic foraminiferal specimens from the Red Sea surface waters were collected and analyzed for their Na/Ca content using laser ablation quadrupole inductively coupled plasma mass spectrometry. Using the Red Sea as a natural laboratory, the calibration covers a broad range of salinities over a steep gradient within the same water mass. For both Globigerinoides ruber and Globigerinoides sacculifer calcite Na/Ca increases with salinity, albeit with a relatively large intraspecimen and interspecimen variability. The field-based calibration is similar for both species from a salinity of 36.8 up to 39.6, while values for G. sacculifer deviate from this trend in the northernmost transect. It is hypothesized that the foraminifera in the northernmost part of the Red Sea are (partly) expatriated and hence should be excluded from the Na/Ca-salinity calibration. Incorporation of Na in foraminiferal calcite therefore provides a potential proxy for salinity, although species-specific calibrations are still required and more research on the effect of temperature is needed.

  9. Quasi-planktonic behavior of foraging top marine predators

    Science.gov (United States)

    Della Penna, Alice; de Monte, Silvia; Kestenare, Elodie; Guinet, Christophe; D'Ovidio, Francesco

    2015-12-01

    Monitoring marine top predators is fundamental for assessing the health and functioning of open ocean ecosystems. Although recently tracking observations have substantially increased, factors determining the horizontal exploration of the ocean by marine predators are still largely unknown, especially at the scale of behavioral switches (1-100 km, days-weeks). It is commonly assumed that the influence of water movement can be neglected for animals capable of swimming faster than the current. Here, we challenge this assumption by combining the use of biologging (GPS and accelerometry), satellite altimetry and in-situ oceanographic data (ADCP and drifting buoys) to investigate the effect of the mesoscale ocean dynamics on a marine predator, the southern elephant seal. A Lagrangian approach reveals that trajectories of elephant seals are characterized by quasi-planktonic bouts where the animals are horizontally drifting. These bouts correspond to periods of increased foraging effort, indicating that in the quasi-planktonic conditions energy is allocated to diving and chasing, rather than in horizontal search of favourable grounds. These results suggest that mesoscale features like eddies and fronts may act as a focal points for trophic interactions not only by bottom-up modulation of nutrient injection, but also by directly entraining horizontal displacements of the upper trophic levels.

  10. Carbohydrate structure: the rocky road to automation.

    Science.gov (United States)

    Agirre, Jon; Davies, Gideon J; Wilson, Keith S; Cowtan, Kevin D

    2017-06-01

    With the introduction of intuitive graphical software, structural biologists who are not experts in crystallography are now able to build complete protein or nucleic acid models rapidly. In contrast, carbohydrates are in a wholly different situation: scant automation exists, with manual building attempts being sometimes toppled by incorrect dictionaries or refinement problems. Sugars are the most stereochemically complex family of biomolecules and, as pyranose rings, have clear conformational preferences. Despite this, all refinement programs may produce high-energy conformations at medium to low resolution, without any support from the electron density. This problem renders the affected structures unusable in glyco-chemical terms. Bringing structural glycobiology up to 'protein standards' will require a total overhaul of the methodology. Time is of the essence, as the community is steadily increasing the production rate of glycoproteins, and electron cryo-microscopy has just started to image them in precisely that resolution range where crystallographic methods falter most. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. A functional carbohydrate chip platform for analysis of carbohydrate-protein interaction

    International Nuclear Information System (INIS)

    Seo, Jeong Hyun; Kim, Chang Sup; Hwang, Byeong Hee; Cha, Hyung Joon

    2010-01-01

    A carbohydrate chip based on glass or other transparent surfaces has been suggested as a potential tool for high-throughput analysis of carbohydrate-protein interactions. Here we proposed a facile, efficient, and cost-effective method whereby diverse carbohydrate types are modified in a single step and directly immobilized onto a glass surface, with retention of functional orientation. We modified various types of carbohydrates by reductive amination, in which reducing sugar groups were coupled with 4-(2-aminoethyl)aniline, which has di-amine groups at both ends. The modified carbohydrates were covalently attached to an amino-reactive NHS-activated glass surface by formation of stable amide bonds. This proposed method was applied for efficient construction of a carbohydrate microarray to analyze carbohydrate-protein interactions. The carbohydrate chip prepared using our method can be successfully used in diverse biomimetic studies of carbohydrates, including carbohydrate-biomolecule interactions, and carbohydrate sensor chip or microarray development for diagnosis and screening.

  12. Technological aspects of functional food-related carbohydrates.

    NARCIS (Netherlands)

    Voragen, A.G.J.

    1998-01-01

    Carbohydrates in food occur as natural constituents or are added as ingredients or additives. The most important endogenous carbohydrates in food are starch, depolymerized starch, sucrose, lactose, glucose, fructose and sorbitol (digestible) and carbohydrates such as raffinose, stachyose, resistant

  13. Biodiversity patterns of plankton assemblages at the extremes of the Red Sea.

    Science.gov (United States)

    Pearman, J K; Kürten, S; Sarma, Y V B; Jones, B H; Carvalho, S

    2016-03-01

    The diversity of microbial plankton has received limited attention in the main basin of the Red Sea. This study investigates changes in the community composition and structure of prokaryotes and eukaryotes at the extremes of the Red Sea along cross-shelf gradients and between the surface and deep chlorophyll maximum. Using molecular methods to target both the 16S and 18S rRNA genes, it was observed that the dominant prokaryotic classes were Acidimicrobiia, Alphaproteobacteria and Cyanobacteria, regardless of the region and depth. The eukaryotes Syndiniophyceae and Dinophyceae between them dominated in the north, with Bacillariophyceae and Mamiellophyceae more prominent in the southern region. Significant differences were observed for prokaryotes and eukaryotes for region, depth and distance from shore. Similarly, it was noticed that communities became less similar with increasing distance from the shore. Canonical correspondence analysis at the class level showed that Mamiellophyceae and Bacillariophyceae correlated with increased nutrients and chlorophyll a found in the southern region, which is influenced by the input of Gulf of Aden Intermediate Water. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Biodiversity patterns of plankton assemblages at the extremes of the Red Sea

    KAUST Repository

    Pearman, John K.

    2016-01-07

    The diversity of microbial plankton has received limited attention in the main basin of the Red Sea. This study investigates changes in the community composition and structure of prokaryotes and eukaryotes at the extremes of the Red Sea along cross-shelf gradients and between the surface and deep chlorophyll maximum. Using molecular methods to target both the 16S and 18S rRNA genes, it was observed that the dominant prokaryotic classes were Acidimicrobiia, Alphaproteobacteria and Cyanobacteria, regardless of the region and depth. The eukaryotes Syndiniophyceae and Dinophyceae between them dominated in the north, with Bacillariophyceae and Mamiellophyceae more prominent in the southern region. Significant differences were observed for prokaryotes and eukaryotes for region, depth and distance from shore. Similarly, it was noticed that communities became less similar with increasing distance from the shore. Canonical correspondence analysis at the class level showed that Mamiellophyceae and Bacillariophyceae correlated with increased nutrients and chlorophyll a found in the southern region, which is influenced by the input of Gulf of Aden Intermediate Water.

  15. Biodiversity patterns of plankton assemblages at the extremes of the Red Sea

    KAUST Repository

    Pearman, John K.; Kurten, Saskia; Yellepeddi, Sarma B.; Jones, Burton; Carvalho, Susana

    2016-01-01

    The diversity of microbial plankton has received limited attention in the main basin of the Red Sea. This study investigates changes in the community composition and structure of prokaryotes and eukaryotes at the extremes of the Red Sea along cross-shelf gradients and between the surface and deep chlorophyll maximum. Using molecular methods to target both the 16S and 18S rRNA genes, it was observed that the dominant prokaryotic classes were Acidimicrobiia, Alphaproteobacteria and Cyanobacteria, regardless of the region and depth. The eukaryotes Syndiniophyceae and Dinophyceae between them dominated in the north, with Bacillariophyceae and Mamiellophyceae more prominent in the southern region. Significant differences were observed for prokaryotes and eukaryotes for region, depth and distance from shore. Similarly, it was noticed that communities became less similar with increasing distance from the shore. Canonical correspondence analysis at the class level showed that Mamiellophyceae and Bacillariophyceae correlated with increased nutrients and chlorophyll a found in the southern region, which is influenced by the input of Gulf of Aden Intermediate Water.

  16. Phenol-Sulfuric Acid Method for Total Carbohydrates

    Science.gov (United States)

    Nielsen, S. Suzanne

    The phenol-sulfuric acid method is a simple and rapid colorimetric method to determine total carbohydrates in a sample. The method detects virtually all classes of carbohydrates, including mono-, di-, oligo-, and polysaccharides. Although the method detects almost all carbohydrates, the absorptivity of the different carbohydrates varies. Thus, unless a sample is known to contain only one carbohydrate, the results must be expressed arbitrarily in terms of one carbohydrate.

  17. ASSESSING THE STATE OF THE PELAGIC HABITAT: A CASE STUDY OF PLANKTON AND ITS ENVIRONMENT IN THE WESTERN IRISH SEA

    Directory of Open Access Journals (Sweden)

    Cordula Scherer

    2016-11-01

    Full Text Available Much work had been undertaken on tracking change in the condition of marine pelagic ecosystems and on identifying regime shifts. However, it is also necessary to relate change to states of good ecosystem health or what the European Marine Strategy Framework Directive (MSFD calls 'Good Environmental Status' (GES. Drawing on existing scientific and legislative principles, including those of OSPAR's 'Strategy to Combat Eutrophication', we propose a framework for assessing the status of what the MSFD calls the 'pelagic habitat' in temperate coastal seas. The framework uses knowledge of local ecohydrodynamic conditions, especially those relating to the stratification and optical environment, to guide expectations of what would be recognised as healthy in terms of ecosystem 'organisation' and 'vigour'. We apply this framework to the seasonally stratified regime of the Western Irish Sea, drawing on published and new work on stratification, nutrient and phytoplankton seasonal cycles, zooplankton, and the implications of plankton community structure and production for higher trophic levels. We conclude that, despite human pressures including nutrient enrichment, and the food-web effects of fisheries, the pelagic ecosystem here is in GES, and hence may be used as a reference for the 'Plankton Index' method of tracking change in state space in seasonally stratified waters.

  18. First records of two planktonic Indo-Pacific diatoms: Chaetoceros bacteriastroides and C. pseudosymmetricus in the Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Marijeta Čalić

    2018-01-01

    Full Text Available Unusual occurrence of planktonic diatom species, Chaetoceros bacteriastroides and Chaetoceros pseudosymmetricus, was noticed in three different marine ecosystems of Adriatic Sea: the Krka Estuary and Telaščica Bay in the Central Adriatic, and in southern Adriatic offshore. From 2010 to 2015, these two Chaetoceros species were recorded in heterogeneous environmental conditions and in a very low abundances. Both species are regarded as very rare in world oceans, and consequently knowledge of their distribution and ecology is rather poor. Primarily described from tropical waters and showing Indo-Pacific distribution, C. bacteriastroides and C. pseudosymmetricus findings in Adriatic represent the northernmost records in world's oceans and seas. For C. pseudosymmetricus this is also the first occurrence in European seas. Areal expansion and introduction of new phytoplankton species in the Adriatic Sea might be related to different circulation regimes in the Ionian Sea and the concurrent rise in sea temperature in the Mediterranean in the last decade. Recent investigations have shown that entering currents, of either Atlantic/Western Mediterranean or Eastern Mediterranean origin, modify the composition of the plankton community in the Adriatic by bringing different newcomers.

  19. C-di-GMP regulates Pseudomonas aeruginosa stress response to tellurite during both planktonic and biofilm modes of growth

    DEFF Research Database (Denmark)

    Chua, Song Lin; Sivakumar, Krishnakumar; Rybtke, Morten Levin

    2015-01-01

    tellurite (TeO3(2-)) exposure induced the intracellular content of the secondary messenger cyclic di-GMP (c-di-GMP) of Pseudomonas aeruginosa. Two diguanylate cyclases (DGCs), SadC and SiaD, were responsible for the increased intracellular content of c-di-GMP. Enhanced c-di-GMP levels by TeO3(2-) further...... increased P. aeruginosa biofilm formation and resistance to TeO3(2-). P. aeruginosa ΔsadCΔsiaD and PAO1/p(lac)-yhjH mutants with low intracellular c-di-GMP content were more sensitive to TeO3(2-) exposure and had low relative fitness compared to the wild-type PAO1 planktonic and biofilm cultures exposed...... to TeO3(2-). Our study provided evidence that c-di-GMP level can play an important role in mediating stress response in microbial communities during both planktonic and biofilm modes of growth....

  20. Glycoside Hydrolases across Environmental Microbial Communities.

    Directory of Open Access Journals (Sweden)

    Renaud Berlemont

    2016-12-01

    Full Text Available Across many environments microbial glycoside hydrolases support the enzymatic processing of carbohydrates, a critical function in many ecosystems. Little is known about how the microbial composition of a community and the potential for carbohydrate processing relate to each other. Here, using 1,934 metagenomic datasets, we linked changes in community composition to variation of potential for carbohydrate processing across environments. We were able to show that each ecosystem-type displays a specific potential for carbohydrate utilization. Most of this potential was associated with just 77 bacterial genera. The GH content in bacterial genera is best described by their taxonomic affiliation. Across metagenomes, fluctuations of the microbial community structure and GH potential for carbohydrate utilization were correlated. Our analysis reveals that both deterministic and stochastic processes contribute to the assembly of complex microbial communities.

  1. Utilization of carbohydrates by radiation processing

    International Nuclear Information System (INIS)

    Kume, T.; Nagasawa, N.; Yoshii, F.

    2002-01-01

    Upgrading and utilization of carbohydrates such as chitosan, sodium alginate, carrageenan, cellulose, pectin have been investigated for recycling these bio-resources and reducing the environmental pollution. These carbohydrates were easily degraded by irradiation and various kinds of biological activities such as anti-microbial activity, promotion of plant growth, suppression of heavy metal stress, phytoalexins induction, etc. were induced. On the other hand, some carbohydrate derivatives, carboxymethylcellulose and carboxymethylstarch, could be crosslinked under certain radiation condition and produce the biodegradable hydrogel for medical and agricultural use

  2. Photosynthetic planulae and planktonic hydroids: contrasting strategies of propagule survival

    Directory of Open Access Journals (Sweden)

    Patrizia Pagliara

    2000-12-01

    Full Text Available Settlement delays can be important to prevent propagule waste when proper settling substrates are not immediately available. Under laboratory conditions, the planulae of Clytia viridicans underwent two alternative developmental patterns. Some settled on the bottom, forming a hydranth-gonotheca complex that produced up to four medusae and later either degenerated or gave rise to a hydroid colony. Other planulae settled right below the air-water interface, forming floating colonies that eventually fell to the bottom and settled. Halecium nanum released planulae with a rich population of symbiotic zooxanthellae that survived into a rearing jar for three months. After a long period of apparent quiescence (possibly fuelled by photosynthetic activities of zooxanthellae the planulae produced new colonies. Both photosynthetic planulae and settlement at the interface air-water allow a delay in the passage from a planktonic to a fully functional benthic life.

  3. Magnetic light cloaking control in the marine planktonic copepod Sapphirina

    Science.gov (United States)

    Kashiwagi, H.; Mizukawa, Y.; Iwasaka, M.; Ohtsuka, S.

    2017-05-01

    We investigated the light cloaking behavior of the marine planktonic copepod Sapphirina under a magnetic field. Optical interferences in the multi-laminated guanine crystal layer beneath the dorsal body surface create a brilliant structural color, which can be almost entirely removed by changing the light reflection. In the investigation, we immersed segments of Sapphirina in seawater contained in an optical chamber. When the derived Sapphirina segments were attached to the container surface, they were inert to magnetic fields up to 300 mT. However, when the back plate segments were attached to the substrate at a point, with most of the plate floating in the seawater, the plate rotated oppositely to the applied magnetic field. In addition, the brilliant parts of the Sapphirina back plate rotated backward and forward by changing the magnetic field directions. Our experiment suggests a new model of an optical micro-electro-mechanical system that is controllable by magnetic fields.

  4. Escape response of planktonic protists to fluid mechanical signals

    DEFF Research Database (Denmark)

    Jakobsen, Hans Henrik

    2001-01-01

    The escape response to fluid mechanical signals was examined in 6 protists, 4 ciliates and 2 dinoflagellates. When exposed to a siphon flow. 3 species of ciliates, Balanion comatum, Strobilidium sp., and Mesodinium pulex, responded with escape jumps. The threshold deformation rates required...... times lower than that of a non-jumping similar sized protist when the predator was Temora longicornis, which captures prey entrained in a feeding current. However, when the predator was the ambush- feeding copepod Acartia tonsa, the predation mortalities of jumping and non-jumping protists were...... of similar magnitude. Escape responses may thus be advantageous in some situations. However, jumping behaviour may also enhance susceptibility to some predators, explaining the different predator avoidance strategies (jumping or not) that have evolved in planktonic protists....

  5. Cenozoic planktonic marine diatom diversity and correlation to climate change

    Science.gov (United States)

    Lazarus, David; Barron, John; Renaudie, Johan; Diver, Patrick; Türke, Andreas

    2014-01-01

    Marine planktonic diatoms export carbon to the deep ocean, playing a key role in the global carbon cycle. Although commonly thought to have diversified over the Cenozoic as global oceans cooled, only two conflicting quantitative reconstructions exist, both from the Neptune deep-sea microfossil occurrences database. Total diversity shows Cenozoic increase but is sample size biased; conventional subsampling shows little net change. We calculate diversity from a separately compiled new diatom species range catalog, and recalculate Neptune subsampled-in-bin diversity using new methods to correct for increasing Cenozoic geographic endemism and decreasing Cenozoic evenness. We find coherent, substantial Cenozoic diversification in both datasets. Many living cold water species, including species important for export productivity, originate only in the latest Miocene or younger. We make a first quantitative comparison of diatom diversity to the global Cenozoic benthic ∂18O (climate) and carbon cycle records (∂13C, and 20-0 Ma pCO2). Warmer climates are strongly correlated with lower diatom diversity (raw: rho = .92, p2 were only moderately higher than today. Diversity is strongly correlated to both ∂13C and pCO2 over the last 15 my (for both: r>.9, detrended r>.6, all p<.001), but only weakly over the earlier Cenozoic, suggesting increasingly strong linkage of diatom and climate evolution in the Neogene. Our results suggest that many living marine planktonic diatom species may be at risk of extinction in future warm oceans, with an unknown but potentially substantial negative impact on the ocean biologic pump and oceanic carbon sequestration. We cannot however extrapolate our my-scale correlations with generic climate proxies to anthropogenic time-scales of warming without additional species-specific information on proximate ecologic controls.

  6. Cenozoic planktonic marine diatom diversity and correlation to climate change.

    Directory of Open Access Journals (Sweden)

    David Lazarus

    Full Text Available Marine planktonic diatoms export carbon to the deep ocean, playing a key role in the global carbon cycle. Although commonly thought to have diversified over the Cenozoic as global oceans cooled, only two conflicting quantitative reconstructions exist, both from the Neptune deep-sea microfossil occurrences database. Total diversity shows Cenozoic increase but is sample size biased; conventional subsampling shows little net change. We calculate diversity from a separately compiled new diatom species range catalog, and recalculate Neptune subsampled-in-bin diversity using new methods to correct for increasing Cenozoic geographic endemism and decreasing Cenozoic evenness. We find coherent, substantial Cenozoic diversification in both datasets. Many living cold water species, including species important for export productivity, originate only in the latest Miocene or younger. We make a first quantitative comparison of diatom diversity to the global Cenozoic benthic ∂(18O (climate and carbon cycle records (∂(13C, and 20-0 Ma pCO2. Warmer climates are strongly correlated with lower diatom diversity (raw: rho = .92, p.9, detrended r>.6, all p<.001, but only weakly over the earlier Cenozoic, suggesting increasingly strong linkage of diatom and climate evolution in the Neogene. Our results suggest that many living marine planktonic diatom species may be at risk of extinction in future warm oceans, with an unknown but potentially substantial negative impact on the ocean biologic pump and oceanic carbon sequestration. We cannot however extrapolate our my-scale correlations with generic climate proxies to anthropogenic time-scales of warming without additional species-specific information on proximate ecologic controls.

  7. Carbohydrate storage and light requirements of tropical moist and dry forest tree species

    NARCIS (Netherlands)

    Poorter, L.; Kitajima, K.

    2007-01-01

    In many plant communities, there is a negative interspecific correlation between relative growth rates and survival of juveniles. This negative correlation is most likely caused by a trade-off between carbon allocation to growth vs. allocation to defense and storage. Nonstructural carbohydrates

  8. Temperature, salinity, transmissivity, pressure, plankton, oxygen, nutrients, chlorophyll, and primary productivity data collected using CTD, bottle, and plankton net from the R/V Italica in the Ross Sea and Magellan Strait during 10th Italian Antarctic Expedition from 1994-11-13 to 1995-04-02 (NCEI Accession 0068289)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, transmissivity, pressure, plankton, oxygen, nutrients, chlorophyll, and primary productivity data collected using CTD, bottle, and plankton...

  9. Carbohydrate plasma expanders for passive tumor targeting

    DEFF Research Database (Denmark)

    Hoffmann, Stefan; Caysa, Henrike; Kuntsche, Judith

    2013-01-01

    The objective of this study was to investigate the suitability of carbohydrate plasma volume expanders as a novel polymer platform for tumor targeting. Many synthetic polymers have already been synthesized for targeted tumor therapy, but potential advantages of these carbohydrates include inexpen...... was characterized in human colon carcinoma xenograft bearing nude mice. A tumor specific accumulation of HES 450 was observed, which proves it’s potential as carrier for passive tumor targeting....

  10. Digestion and metabolism of carbohydrates in fish

    OpenAIRE

    Abro, Rani

    2014-01-01

    This thesis deals with the digestion and metabolism of carbohydrates in Arctic charr, Eurasian perch and tilapia. Two sources of carbohydrates, native starch (wheat) and chitin (zygomycete biomass), were evaluated. Gut tissue of Arctic charr displayed significant chitinase activity, of both endo- and exo-chitinase forms. Moreover, the distribution pattern along the gastrointestinal tract of Arctic charr differed between endo-chitinase and exo-chitinase. The endo-chitinase activity in sto...

  11. The old and the new plankton: ecological replacement of associations of mollusc plankton and giant filter feeders after the Cretaceous?

    Directory of Open Access Journals (Sweden)

    Amane Tajika

    2018-01-01

    Full Text Available Owing to their great diversity and abundance, ammonites and belemnites represented key elements in Mesozoic food webs. Because of their extreme ontogenetic size increase by up to three orders of magnitude, their position in the food webs likely changed during ontogeny. Here, we reconstruct the number of eggs laid by large adult females of these cephalopods and discuss developmental shifts in their ecologic roles. Based on similarities in conch morphology, size, habitat and abundance, we suggest that similar niches occupied in the Cretaceous by juvenile ammonites and belemnites were vacated during the extinction and later partially filled by holoplanktonic gastropods. As primary consumers, these extinct cephalopod groups were important constituents of the plankton and a principal food source for planktivorous organisms. As victims or, respectively, profiteers of this case of ecological replacement, filter feeding chondrichthyans and cetaceans likely filled the niches formerly occupied by large pachycormid fishes during the Jurassic and Cretaceous.

  12. The carbohydrate sequence markup language (CabosML): an XML description of carbohydrate structures.

    Science.gov (United States)

    Kikuchi, Norihiro; Kameyama, Akihiko; Nakaya, Shuuichi; Ito, Hiromi; Sato, Takashi; Shikanai, Toshihide; Takahashi, Yoriko; Narimatsu, Hisashi

    2005-04-15

    Bioinformatics resources for glycomics are very poor as compared with those for genomics and proteomics. The complexity of carbohydrate sequences makes it difficult to define a common language to represent them, and the development of bioinformatics tools for glycomics has not progressed. In this study, we developed a carbohydrate sequence markup language (CabosML), an XML description of carbohydrate structures. The language definition (XML Schema) and an experimental database of carbohydrate structures using an XML database management system are available at http://www.phoenix.hydra.mki.co.jp/CabosDemo.html kikuchi@hydra.mki.co.jp.

  13. Examination of a high resolution laser optical plankton counter and FlowCAM for measuring plankton concentration and size

    Science.gov (United States)

    Kydd, Jocelyn; Rajakaruna, Harshana; Briski, Elizabeta; Bailey, Sarah

    2018-03-01

    Many commercial ships will soon begin to use treatment systems to manage their ballast water and reduce the global transfer of harmful aquatic organisms and pathogens in accordance with upcoming International Maritime Organization regulations. As a result, rapid and accurate automated methods will be needed to monitoring compliance of ships' ballast water. We examined two automated particle counters for monitoring organisms ≥ 50 μm in minimum dimension: a High Resolution Laser Optical Plankton Counter (HR-LOPC), and a Flow Cytometer with digital imaging Microscope (FlowCAM), in comparison to traditional (manual) microscopy considering plankton concentration, size frequency distributions and particle size measurements. The automated tools tended to underestimate particle concentration compared to standard microscopy, but gave similar results in terms of relative abundance of individual taxa. For most taxa, particle size measurements generated by FlowCAM ABD (Area Based Diameter) were more similar to microscope measurements than were those by FlowCAM ESD (Equivalent Spherical Diameter), though there was a mismatch in size estimates for some organisms between the FlowCAM ABD and microscope due to orientation and complex morphology. When a single problematic taxon is very abundant, the resulting size frequency distribution curves can become skewed, as was observed with Asterionella in this study. In particular, special consideration is needed when utilizing automated tools to analyse samples containing colonial species. Re-analysis of the size frequency distributions with the removal of Asterionella from FlowCAM and microscope data resulted in more similar curves across methods with FlowCAM ABD having the best fit compared to the microscope, although microscope concentration estimates were still significantly higher than estimates from the other methods. The results of our study indicate that both automated tools can generate frequency distributions of particles

  14. Carbohydrate Nutrition and Team Sport Performance.

    Science.gov (United States)

    Williams, Clyde; Rollo, Ian

    2015-11-01

    The common pattern of play in 'team sports' is 'stop and go', i.e. where players perform repeated bouts of brief high-intensity exercise punctuated by lower intensity activity. Sprints are generally 2-4 s long and recovery between sprints is of variable length. Energy production during brief sprints is derived from the degradation of intra-muscular phosphocreatine and glycogen (anaerobic metabolism). Prolonged periods of multiple sprints drain muscle glycogen stores, leading to a decrease in power output and a reduction in general work rate during training and competition. The impact of dietary carbohydrate interventions on team sport performance have been typically assessed using intermittent variable-speed shuttle running over a distance of 20 m. This method has evolved to include specific work to rest ratios and skills specific to team sports such as soccer, rugby and basketball. Increasing liver and muscle carbohydrate stores before sports helps delay the onset of fatigue during prolonged intermittent variable-speed running. Carbohydrate intake during exercise, typically ingested as carbohydrate-electrolyte solutions, is also associated with improved performance. The mechanisms responsible are likely to be the availability of carbohydrate as a substrate for central and peripheral functions. Variable-speed running in hot environments is limited by the degree of hyperthermia before muscle glycogen availability becomes a significant contributor to the onset of fatigue. Finally, ingesting carbohydrate immediately after training and competition will rapidly recover liver and muscle glycogen stores.

  15. Planktonic production and respiration in a subtropical lake dominated by Cyanobacteria.

    Science.gov (United States)

    Tonetta, D; Laudares-Silva, R; Petrucio, M M

    2015-05-01

    Planktonic primary production and respiration rates were estimated in a subtropical coastal lake dominated by Cyanobacteria in order to investigate the temporal and vertical variation in this lake and to evaluate its relationships with limnological variables and phytoplankton. Light and dark bottles were incubated at four different depths in the central part of the lake and were performed bimonthly from June/2009 to December/2010. No significant difference was evident among depths in relation to phytoplankton, limnological variables and metabolic rates. However, the highest production rates were recorded at the surface, and decreased towards the bottom, coupled with phytoplanktonic photosynthetic capacity. Wind induced mixing in Peri Lake played an important role in nutrient and phytoplankton redistribution, characterizing this lake as polymictic. According to density and biovolume, the phytoplankton community was dominated by filamentous Cyanobacteria, especially Cylindrospermopsis raciborskii (Woloszynska) Seenayya and Subba-Raju. This study has shown that both water temperature and nutrient availability drive phytoplankton growth and consequently the temporal variation in metabolic rates, where respiration is higher than primary production.

  16. Planktonic production and respiration in a subtropical lake dominated by Cyanobacteria

    Directory of Open Access Journals (Sweden)

    D. Tonetta

    Full Text Available Planktonic primary production and respiration rates were estimated in a subtropical coastal lake dominated by Cyanobacteria in order to investigate the temporal and vertical variation in this lake and to evaluate its relationships with limnological variables and phytoplankton. Light and dark bottles were incubated at four different depths in the central part of the lake and were performed bimonthly from June/2009 to December/2010. No significant difference was evident among depths in relation to phytoplankton, limnological variables and metabolic rates. However, the highest production rates were recorded at the surface, and decreased towards the bottom, coupled with phytoplanktonic photosynthetic capacity. Wind induced mixing in Peri Lake played an important role in nutrient and phytoplankton redistribution, characterizing this lake as polymictic. According to density and biovolume, the phytoplankton community was dominated by filamentous Cyanobacteria, especially Cylindrospermopsis raciborskii (Woloszynska Seenayya and Subba-Raju. This study has shown that both water temperature and nutrient availability drive phytoplankton growth and consequently the temporal variation in metabolic rates, where respiration is higher than primary production.

  17. Species-specific separation of lake plankton reveals divergent food assimilation patterns in rotifers.

    Science.gov (United States)

    Burian, Alfred; Kainz, Martin J; Schagerl, Michael; Yasindi, Andrew

    2014-06-01

    1. The analysis of functional groups with a resolution to the individual species level is a basic requirement to better understand complex interactions in aquatic food webs. Species-specific stable isotope analyses are currently applied to analyse the trophic role of large zooplankton or fish species, but technical constraints complicate their application to smaller-sized plankton. 2. We investigated rotifer food assimilation during a short-term microzooplankton bloom in the East African soda lake Nakuru by developing a method for species-specific sampling of rotifers. 3. The two dominant rotifers, Brachionus plicatilis and Brachionus dimidiatus , were separated to single-species samples (purity >95%) and significantly differed in their isotopic values (4.1‰ in δ 13 C and 1.5‰ in δ 15 N). Bayesian mixing models indicated that isotopic differences were caused by different assimilation of filamentous cyanobacteria and particles plicatilis (48%), whereas it was hardly ingested by B. dimidiatus . Overall, A . fusiformis was, relative to its biomass, assimilated to small extents, demonstrating a high grazing resistance of this species. 5. In combination with high population densities, these results demonstrate a strong potential of rotifer blooms to shape phytoplankton communities and are the first in situ demonstration of a quantitatively important direct trophic link between rotifers and filamentous cyanobacteria.

  18. Effects of ultraviolet radiation on the lower levels of the planktonic food web in Antarctica

    International Nuclear Information System (INIS)

    Ferreyra, Gustavo A.; Schloss, Irene; Tosonotto, Gabriela; Calvino, Eduardo; Rodriguez, Silvia; Cantoni, Leonardo; Gonzalez, Oscar; Ulrich, Alejandro; Hernando, Marcelo; Hernandez, Edgardo; Oyarbide, Fabricio

    2004-01-01

    Full text: Most of the studies that investigated the effects of ultraviolet radiation (UVR, 280-400 NM) on the first levels of the marine food web used experimental approaches (in situ incubations, micro and mesocosms). However, research on the responses to UVR of the micro community in their natural environment is scarce. A time series study including most of the oceanographic parameters described as controlling bacteria and phytoplankton dynamics was carried out (PAR, tidal mixing, turbulent mixing by winds and currents, nutrient stress). In this case, however, the effects of ultraviolet A and B (UVB, 280-320 nm and UVA, 320-400 nm, respectively) were added as forcing parameters. Fieldwork was done in the vicinity of Melchior Station (64 degrees 20' S, 62 degrees 59' W, Observatory Island). It involved the automated measurement of physical variables (currents, tides and meteorological data), as well as discrete sampling of physical (salinity, temperature), chemical (macro nutrients) and biological variables (bacterial and phytoplankton abundance and production, PSI I system, photo protective compounds). Sub-surface sampling (0.5 m depth) was conducted with 5 L Niskin bottles at a fixed station (sampling every 6/12 h centered at local noon during the whole study period), and vertical profiles at 6 fixed depths (0, 5, 10, 20, 30 and 50 m) were done every four days. The whole study lasted for one month, from February 11 to March 12 2002. Average upper mixed layer (UML) was around 20 m and the depth of the euphotic zone (1% of incident radiation) for UVB and UVA was respectively 17 and 32 m, suggesting a strong influence of UVR on cells within the UML. PSII activity showed a significant inverse correlation with UVB, phased with irradiance oscillations. Bacterio plankton and phytoplankton biomass and production of both presented a similar response, but minimum values were lagged by 4-6 h from UVR maxima. Mycosporin like aminoacids (MAA's) were also phased and directly

  19. Spatial variability in phytoplankton community structure along the eastern Arabian Sea during the onset of south-west monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Ahmed, A.; Kurian, S.; Gauns, M.; ChndrasekharaRao, A.V.; Mulla, A.; Naik, B.; Naik, H.; Naqvi, S.W.A.

    The Arabian Sea experiences moderate to weak upwelling along the south-west coast of India, which subsequently propagates towards the north. This causes variation in plankton community composition, which is addressed in the present study. Here we...

  20. Metabolic aspects of low carbohydrate diets and exercise

    Directory of Open Access Journals (Sweden)

    Peters Sandra

    2004-01-01

    Full Text Available Abstract Following a low carbohydrate diet, there is a shift towards more fat and less carbohydrate oxidation to provide energy to skeletal muscle, both at rest and during exercise. This review summarizes recent work on human skeletal muscle carbohydrate and fat metabolic adaptations to a low carbohydrate diet, focusing mainly on pyruvate dehydrogenase and pyruvate dehydrogenase kinase, and how these changes relate to the capacity for carbohydrate oxidation during exercise.

  1. Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

    KAUST Repository

    Garcia-Corral, Lara S.; Martinez Ayala, Juan; Duarte, Carlos M.; Agusti, Susana

    2015-01-01

    . The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A) may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely

  2. Planktonic foraminifera from a quaternary deep sea core from the southern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Rao, P.S.; Pattan, J.N.

    An investigation on planktonic foraminifera and calcium carbonate content of a box core collected at a depth of 2556 m from the southern part of the Arabian sea indicates faunal changes depicting Quaternary climatic fluctuations. Based on the study...

  3. Modeling the distribution of colonial species to improve estimation of plankton concentration in ballast water

    Science.gov (United States)

    Rajakaruna, Harshana; VandenByllaardt, Julie; Kydd, Jocelyn; Bailey, Sarah

    2018-03-01

    The International Maritime Organization (IMO) has set limits on allowable plankton concentrations in ballast water discharge to minimize aquatic invasions globally. Previous guidance on ballast water sampling and compliance decision thresholds was based on the assumption that probability distributions of plankton are Poisson when spatially homogenous, or negative binomial when heterogeneous. We propose a hierarchical probability model, which incorporates distributions at the level of particles (i.e., discrete individuals plus colonies per unit volume) and also within particles (i.e., individuals per particle) to estimate the average plankton concentration in ballast water. We examined the performance of the models using data for plankton in the size class ≥ 10 μm and test ballast water compliance using the above models.

  4. An Experimental-Numerical Study of Small Scale Flow Interaction with Bioluminescent Plankton

    National Research Council Canada - National Science Library

    Latz, Michael

    1998-01-01

    Numerical and experimental approaches were used to investigate the effects of quantified flow stimuli on bioluminescence sUmulatidn at the small length and time scales appropriate for individual plankton...

  5. Sediment traps as a new tool for estimation of longevity of planktonic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    Sediment trap technique provides time series data of sinking particles (faunal and sediment) from surface to bottom of the sea. Besides many other applications, data can also be used to estimate life span of planktonic foraminifera. Based on rearing...

  6. Response of planktonic bacteria of New Calabar River to zinc stress ...

    African Journals Online (AJOL)

    Response of planktonic bacteria of New Calabar River to zinc stress. ... The result of the in vitro study indicated that the bacterial strains are sensitive to Zn2+ stress. Therefore, Zn2+ contamination would ... Featuring journals from 32 Countries:.

  7. Influence of monsoon upwelling on the planktonic foraminifera off Oman during Late Quaternary

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.

    Planktonic foraminifer abundances, fluxes, test sizes, and coiling properties are influenced in various ways by the southwest monsoon winds and associated upwelling in the western Arabian Sea. The influence of monsoon driven upwelling...

  8. 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...

  9. PFR²: a curated database of planktonic foraminifera 18S ribosomal DNA as a resource for studies of plankton ecology, biogeography and evolution.

    Science.gov (United States)

    Morard, Raphaël; Darling, Kate F; Mahé, Frédéric; Audic, Stéphane; Ujiié, Yurika; Weiner, Agnes K M; André, Aurore; Seears, Heidi A; Wade, Christopher M; Quillévéré, Frédéric; Douady, Christophe J; Escarguel, Gilles; de Garidel-Thoron, Thibault; Siccha, Michael; Kucera, Michal; de Vargas, Colomban

    2015-11-01

    Planktonic foraminifera (Rhizaria) are ubiquitous marine pelagic protists producing calcareous shells with conspicuous morphology. They play an important role in the marine carbon cycle, and their exceptional fossil record serves as the basis for biochronostratigraphy and past climate reconstructions. A major worldwide sampling effort over the last two decades has resulted in the establishment of multiple large collections of cryopreserved individual planktonic foraminifera samples. Thousands of 18S rDNA partial sequences have been generated, representing all major known morphological taxa across their worldwide oceanic range. This comprehensive data coverage provides an opportunity to assess patterns of molecular ecology and evolution in a holistic way for an entire group of planktonic protists. We combined all available published and unpublished genetic data to build PFR(2), the Planktonic foraminifera Ribosomal Reference database. The first version of the database includes 3322 reference 18S rDNA sequences belonging to 32 of the 47 known morphospecies of extant planktonic foraminifera, collected from 460 oceanic stations. All sequences have been rigorously taxonomically curated using a six-rank annotation system fully resolved to the morphological species level and linked to a series of metadata. The PFR(2) website, available at http://pfr2.sb-roscoff.fr, allows downloading the entire database or specific sections, as well as the identification of new planktonic foraminiferal sequences. Its novel, fully documented curation process integrates advances in morphological and molecular taxonomy. It allows for an increase in its taxonomic resolution and assures that integrity is maintained by including a complete contingency tracking of annotations and assuring that the annotations remain internally consistent. © 2015 John Wiley & Sons Ltd.

  10. Seasonal diversity of planktonic protists in Southwestern Alberta rivers over a 1-year period as revealed by terminal restriction fragment length polymorphism and 18S rRNA gene library analyses.

    Science.gov (United States)

    Thomas, Matthew C; Selinger, L Brent; Inglis, G Douglas

    2012-08-01

    The temporal dynamics of planktonic protists in river water have received limited attention despite their ecological significance and recent studies linking phagotrophic protists to the persistence of human-pathogenic bacteria. Using molecular-based techniques targeting the 18S rRNA gene, we studied the seasonal diversity of planktonic protists in Southwestern Alberta rivers (Oldman River Basin) over a 1-year period. Nonmetric multidimensional scaling analysis of terminal restriction fragment length polymorphism (T-RFLP) data revealed distinct shifts in protistan community profiles that corresponded to season rather than geographical location. Community structures were examined by using clone library analysis; HaeIII restriction profiles of 18S rRNA gene amplicons were used to remove prevalent solanaceous plant clones prior to sequencing. Sanger sequencing of the V1-to-V3 region of the 18S rRNA gene libraries from spring, summer, fall, and winter supported the T-RFLP results and showed marked seasonal differences in the protistan community structure. The spring library was dominated by Chloroplastidae (29.8%), Centrohelida (28.1%), and Alveolata (25.5%), while the summer and fall libraries contained primarily fungal clones (83.0% and 88.0%, respectively). Alveolata (35.6%), Euglenozoa (24.4%), Chloroplastida (15.6%), and Fungi (15.6%) dominated the winter library. These data demonstrate that planktonic protists, including protozoa, are abundant in river water in Southwestern Alberta and that conspicuous seasonal shifts occur in the community structure.

  11. Sensitivity of planktonic and biofilm-associated Aeromonas spp. to ionizing radiation

    International Nuclear Information System (INIS)

    Nagar, Vandan; Bandekar, J.R.

    2015-01-01

    Genus Aeromonas has emerged as an important human pathogen because it causes a variety of diseases including gastroenteritis and extra-intestinal infections. Aeromonas have the ability to adhere and form biofilms on food surfaces and food contact surfaces. Biofilm formation on foods and food contact surfaces is the major reason for contamination, cross contamination and post-processing contamination of the final food product leading to food spoilage, product rejection, economic losses and food-borne diseases. Biofilms have shown high resistance to heat, desiccation, acidic condition, high salt concentration, antibiotics and other food preservatives. Earlier studies in our laboratory have shown that ionizing radiation effectively inactivates Aeromonas in different food products. However, the relative efficacy of this process against biofilm associated cells versus free-living planktonic cells of Aeromonas is not well documented. Therefore, the dose of gamma radiation required to reduce the population by 90% (D10) was calculated for planktonic and biofilm-associated A. salmonicida Y567 and A. hydrophila A331 cells. Both A. hydrophila A331 and A. salmonicida Y567 expressed significant ability to attach and grow on glass surface following incubation at 30℃ in TSB. Ionizing radiation effectively reduced the populations of both planktonic and biofilm-associated cells for both the strains. Mean cell counts of survivors and surviving fraction of planktonic and biofilm-associated cells decreased with increased irradiation doses. The D10 values of planktonic cells and biofilm cells for A. salmonicida (Y567) were 232.65 Gy and 248.41 Gy, respectively; whereas, the D10 values of planktonic cells and biofilm cells for A. hydrophila (A331) were 249.2 Gy and 240.2 Gy respectively. No significant difference in the D10 values of planktonic and biofilm associated Aeromonas was observed. The influence of the cultured state of the organism, i.e., planktonic versus biofilm associated

  12. Factors Affecting Catalase Expression in Pseudomonas aeruginosa Biofilms and Planktonic Cells

    OpenAIRE

    Frederick, Jesse R.; Elkins, James G.; Bollinger, Nikki; Hassett, Daniel J.; McDermott, Timothy R.

    2001-01-01

    Previous work with Pseudomonas aeruginosa showed that catalase activity in biofilms was significantly reduced relative to that in planktonic cells. To better understand biofilm physiology, we examined possible explanations for the differential expression of catalase in cells cultured in these two different conditions. For maximal catalase activity, biofilm cells required significantly more iron (25 μM as FeCl3) in the medium, whereas planktonic cultures required no addition of iron. However, ...

  13. Dosimetry of natural and man-made alpha emitters in plankton

    International Nuclear Information System (INIS)

    Paschoa, A.S.; Baptista, G.B.; Wrenn, M.E.; Eisenbrid, M.

    1980-11-01

    Comparison between the natural and man-made alpha radiation dose rates to plankton can be important for predicting the potential long-term effects on aquatic biota resulting from the routine or accidental radioactive releases from the nuclear fuel cycle. A contribution is made here towards the goal of comparing natural with man-made alpha radiation dose rates to plankton using the same method of calculation in both cases. (Author) [pt

  14. Emergent Patterns of Diversity and Dynamics in Natural Populations of Planktonic Vibrio Bacteria

    Science.gov (United States)

    2005-06-01

    1973. Ecology of Vibrio parahemolyticus in mixed-template amplifications: formation, consequences and elimination by Chesapeake Bay. J. Bacteriol. 113...Science 1930 and Engineering DOCTORAL DISSERTATION Emergent Patterns of Diversity and Dynamics in Natural Populations of Planktonic Vibrio Bacteria by...DYNAMICS IN NATURAL POPULATIONS OF PLANKTONIC VIBRIO BACTERIA by Janelle Ren6e Thompson B.S. Biological Sciences, Stanford University 1998 M.S

  15. Using Carbohydrate Interaction Assays to Reveal Novel Binding Sites in Carbohydrate Active Enzymes

    DEFF Research Database (Denmark)

    Cockburn, Darrell; Wilkens, Casper; Dilokpimol, Adiphol

    2016-01-01

    Carbohydrate active enzymes often contain auxiliary binding sites located either on independent domains termed carbohydrate binding modules (CBMs) or as so-called surface binding sites (SBSs) on the catalytic module at a certain distance from the active site. The SBSs are usually critical...

  16. Abundance of plankton population densities in relation to bottom soil textural types in aquaculture ponds

    Directory of Open Access Journals (Sweden)

    F. Siddika

    2012-06-01

    Full Text Available Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1, with loam (T2 and with clay loam (T3. The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7, Cyanophyceae (5, Bacillariophyceae (5, Euglenophyceae (2 and Dinophyceae (1. On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7 and Rotifera (6. The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to medium-type bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds.

  17. [Effect of Pseudomonas aeruginosa exometabolites on planktonic and biofilm cultures of Escherichia coli].

    Science.gov (United States)

    Kuznetsova, M V; Karpunina, T I; Maslennikova, I L; Nesterova, L Iu; Demakov, V A

    2012-01-01

    Study the effect of P. aeruginosa exometabolites on planktonic and biofilm cultures of bioluminescent E. coli strain. E. coli K12 TG1 (pF1 lux+ Ap(r)) recombinant bioluminescent strain, P. aeruginosa ATCC 27853 reference strain and 2 nosocomial isolates were used. Pyocyanin and pyoverdin content in supernatant of P. aeruginosa over-night cultures was evaluated according to E. Deziel et al. (2001). Planktonic and biofilm cultures of E. coli were obtained in 96-well plates (LB, statically, 37 degrees C), optical density of plankton, film biomass (OD600, OD580) and bioluminescence in plankton and biofilm were evaluated in microplate reader Infiniti M200 (Tecan, Austria). P. aeruginosa exometabolites increased the duration of lag-phase in E. coli, and short term exposition inhibited luminescence of planktonic cells. These effects are determined by bactericidal action ofpyocyanin and pyoverdin. Supernatants ofover-night cultures of P. aeruginosa inhibit formation of biofilm and disrupt the formed biofilm of E. coli. Effect of pyocyanin and pyoverdin on these processes is not established, other factors may have higher significance. Bioluminescence of E. coli K12 TGI that reflects the energetic status of the cell allows to evaluate and prognose the character of coexistence of P. aeruginosa in combined with E. coli planktonic and biofilm culture.

  18. Single tag for total carbohydrate analysis.

    Science.gov (United States)

    Anumula, Kalyan Rao

    2014-07-15

    Anthranilic acid (2-aminobenzoic acid, 2-AA) has the remarkable property of reacting rapidly with every type of reducing carbohydrate. Reactivity of 2-AA with carbohydrates in aqueous solutions surpasses all other tags reported to date. This unique capability is attributed to the strategically located -COOH which accelerates Schiff base formation. Monosaccharides, oligosaccharides (N-, O-, and lipid linked and glycans in secretory fluids), glycosaminoglycans, and polysaccharides can be easily labeled with 2-AA. With 2-AA, labeling is simple in aqueous solutions containing proteins, peptides, buffer salts, and other ingredients (e.g., PNGase F, glycosidase, and transferase reaction mixtures). In contrast, other tags require relatively pure glycans for labeling in anhydrous dimethyl sulfoxide-acetic acid medium. Acidic conditions are known to cause desialylation, thus requiring a great deal of attention to sample preparation. Simpler labeling is achieved with 2-AA within 30-60 min in mild acetate-borate buffered solution. 2-AA provides the highest sensitivity and resolution in chromatographic methods for carbohydrate analysis in a simple manner. Additionally, 2-AA is uniquely qualified for quantitative analysis by mass spectrometry in the negative mode. Analyses of 2-AA-labeled carbohydrates by electrophoresis and other techniques have been reported. Examples cited here demonstrate that 2-AA is the universal tag for total carbohydrate analysis. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Ingestion and transfer of microplastics in the planktonic food web

    International Nuclear Information System (INIS)

    Setälä, Outi; Fleming-Lehtinen, Vivi; Lehtiniemi, Maiju

    2014-01-01

    Experiments were carried out with different Baltic Sea zooplankton taxa to scan their potential to ingest plastics. Mysid shrimps, copepods, cladocerans, rotifers, polychaete larvae and ciliates were exposed to 10 μm fluorescent polystyrene microspheres. These experiments showed ingestion of microspheres in all taxa studied. The highest percentage of individuals with ingested spheres was found in pelagic polychaete larvae, Marenzelleria spp. Experiments with the copepod Eurytemora affinis and the mysid shrimp Neomysis integer showed egestion of microspheres within 12 h. Food web transfer experiments were done by offering zooplankton labelled with ingested microspheres to mysid shrimps. Microscopy observations of mysid intestine showed the presence of zooplankton prey and microspheres after 3 h incubation. This study shows for the first time the potential of plastic microparticle transfer via planktonic organisms from one trophic level (mesozooplankton) to a higher level (macrozooplankton). The impacts of plastic transfer and possible accumulation in the food web need further investigations. -- Highlights: • Experiments show the potential of ingestion of plastics by various zooplankton taxa. • This ingestion of plastics can be indirect via other zooplankton organisms. • There may be several alternate routes for microplastic transfer in the food webs. -- Experiments with zooplankton and microspheres showed ingestion of spheres by zpl and the transfer of ingested microspheres to higher trophic level organisms via labelled zooplankton

  20. Modeling physiological processes in plankton on enzyme kinetic principles

    Directory of Open Access Journals (Sweden)

    Ted Packard

    2004-04-01

    Full Text Available Many ecologically important chemical transformations in the ocean are controlled by biochemical enzyme reactions in plankton. Nitrogenase regulates the transformation of N2 to ammonium in some cyanobacteria and serves as the entryway for N2 into the ocean biosphere. Nitrate reductase controls the reduction of NO3 to NO2 and hence new production in phytoplankton. The respiratory electron transfer system in all organisms links the carbon oxidation reactions of intermediary metabolism with the reduction of oxygen in respiration. Rubisco controls the fixation of CO2 into organic matter in phytoplankton and thus is the major entry point of carbon into the oceanic biosphere. In addition to these, there are the enzymes that control CO2 production, NH4 excretion and the fluxes of phosphate. Some of these enzymes have been recognized and researched by marine scientists in the last thirty years. However, until recently the kinetic principles of enzyme control have not been exploited to formulate accurate mathematical equations of the controlling physiological expressions. Were such expressions available they would increase our power to predict the rates of chemical transformations in the extracellular environment of microbial populations whether this extracellular environment is culture media or the ocean. Here we formulate from the principles of bisubstrate enzyme kinetics, mathematical expressions for the processes of NO3 reduction, O2 consumption, N2 fixation, total nitrogen uptake.

  1. A light-induced shortcut in the planktonic microbial loop

    Science.gov (United States)

    Ptacnik, Robert; Gomes, Ana; Royer, Sarah-Jeanne; Berger, Stella A.; Calbet, Albert; Nejstgaard, Jens C.; Gasol, Josep M.; Isari, Stamatina; Moorthi, Stefanie D.; Ptacnikova, Radka; Striebel, Maren; Sazhin, Andrey F.; Tsagaraki, Tatiana M.; Zervoudaki, Soultana; Altoja, Kristi; Dimitriou, Panagiotis D.; Laas, Peeter; Gazihan, Ayse; Martínez, Rodrigo A.; Schabhüttl, Stefanie; Santi, Ioulia; Sousoni, Despoina; Pitta, Paraskevi

    2016-07-01

    Mixotrophs combine photosynthesis with phagotrophy to cover their demands in energy and essential nutrients. This gives them a competitive advantage under oligotropihc conditions, where nutrients and bacteria concentrations are low. As the advantage for the mixotroph depends on light, the competition between mixo- and heterotrophic bacterivores should be regulated by light. To test this hypothesis, we incubated natural plankton from the ultra-oligotrophic Eastern Mediterranean in a set of mesocosms maintained at 4 light levels spanning a 10-fold light gradient. Picoplankton (heterotrophic bacteria (HB), pico-sized cyanobacteria, and small-sized flagellates) showed the fastest and most marked response to light, with pronounced predator-prey cycles, in the high-light treatments. Albeit cell specific activity of heterotrophic bacteria was constant across the light gradient, bacterial abundances exhibited an inverse relationship with light. This pattern was explained by light-induced top-down control of HB by bacterivorous phototrophic eukaryotes (PE), which was evidenced by a significant inverse relationship between HB net growth rate and PE abundances. Our results show that light mediates the impact of mixotrophic bacterivores. As mixo- and heterotrophs differ in the way they remineralize nutrients, these results have far-reaching implications for how nutrient cycling is affected by light.

  2. A light-induced shortcut in the planktonic microbial loop

    KAUST Repository

    Ptacnik, Robert

    2016-07-11

    Mixotrophs combine photosynthesis with phagotrophy to cover their demands in energy and essential nutrients. This gives them a competitive advantage under oligotropihc conditions, where nutrients and bacteria concentrations are low. As the advantage for the mixotroph depends on light, the competition between mixo- and heterotrophic bacterivores should be regulated by light. To test this hypothesis, we incubated natural plankton from the ultra-oligotrophic Eastern Mediterranean in a set of mesocosms maintained at 4 light levels spanning a 10-fold light gradient. Picoplankton (heterotrophic bacteria (HB), pico-sized cyanobacteria, and small-sized flagellates) showed the fastest and most marked response to light, with pronounced predator-prey cycles, in the high-light treatments. Albeit cell specific activity of heterotrophic bacteria was constant across the light gradient, bacterial abundances exhibited an inverse relationship with light. This pattern was explained by light-induced top-down control of HB by bacterivorous phototrophic eukaryotes (PE), which was evidenced by a significant inverse relationship between HB net growth rate and PE abundances. Our results show that light mediates the impact of mixotrophic bacterivores. As mixo- and heterotrophs differ in the way they remineralize nutrients, these results have far-reaching implications for how nutrient cycling is affected by light.

  3. A light-induced shortcut in the planktonic microbial loop

    KAUST Repository

    Ptacnik, Robert; Gomes, Ana; Royer, Sarah-Jeanne; Berger, Stella A.; Calbet, Albert; Nejstgaard, Jens C.; Gasol, Josep M.; Isari, Stamatina; Moorthi, Stefanie D.; Ptacnikova, Radka; Striebel, Maren; Sazhin, Andrey F.; Tsagaraki, Tatiana M.; Zervoudaki, Soultana; Altoja, Kristi; Dimitriou, Panagiotis D.; Laas, Peeter; Gazihan, Ayse; Martí nez, Rodrigo A.; Schabhü ttl, Stefanie; Santi, Ioulia; Sousoni, Despoina; Pitta, Paraskevi

    2016-01-01

    Mixotrophs combine photosynthesis with phagotrophy to cover their demands in energy and essential nutrients. This gives them a competitive advantage under oligotropihc conditions, where nutrients and bacteria concentrations are low. As the advantage for the mixotroph depends on light, the competition between mixo- and heterotrophic bacterivores should be regulated by light. To test this hypothesis, we incubated natural plankton from the ultra-oligotrophic Eastern Mediterranean in a set of mesocosms maintained at 4 light levels spanning a 10-fold light gradient. Picoplankton (heterotrophic bacteria (HB), pico-sized cyanobacteria, and small-sized flagellates) showed the fastest and most marked response to light, with pronounced predator-prey cycles, in the high-light treatments. Albeit cell specific activity of heterotrophic bacteria was constant across the light gradient, bacterial abundances exhibited an inverse relationship with light. This pattern was explained by light-induced top-down control of HB by bacterivorous phototrophic eukaryotes (PE), which was evidenced by a significant inverse relationship between HB net growth rate and PE abundances. Our results show that light mediates the impact of mixotrophic bacterivores. As mixo- and heterotrophs differ in the way they remineralize nutrients, these results have far-reaching implications for how nutrient cycling is affected by light.

  4. Radiocarbon dating of planktonic foraminifer shells: A cautionary tale

    Science.gov (United States)

    Mekik, Figen

    2014-01-01

    rate, bioturbation, winnowing, and calcite dissolution produce significant radiocarbon age offsets among multiple species of coexisting planktonic foraminifers and pteropod fragments. We compare the radiocarbon age of foraminifer species and pteropod fragments with estimates of percent calcite dissolved made with a sedimentary proxy (Globorotalia menardii fragmentation index—MFI) to delineate the effect of dissolution on radiocarbon age of foraminifers. Data from two core top transects on the Rio Grande Rise (RIO) and Ontong Java Plateau (OJP) and from down core sediments of varying sedimentation rates in the tropical Pacific (ME-27, MD98 2177, and MW91-9 56GGC) reveal that sediments with the greatest accumulation rates produce the least age offsets among coexisting species. Age offsets among coexisting foraminifers are about 3500 years on RIO, and 1000 years on OJP. Two core tops from RIO yield an age of the Last Glacial Maximum possibly due to mass displacement of younger sediments downslope. Foraminifer age increases with increasing dissolution and there is a consistent pattern of older foraminifer fragments coexisting with younger whole shells of the same species. The only exception is sediments which have experienced high dissolution where fragments are younger than whole shells. The age offset between fragments of G. menardii and its coexisting whole shells does not exceed the age offset among other coexisting foraminifer species in the same core tops.

  5. Automatic plankton image classification combining multiple view features via multiple kernel learning.

    Science.gov (United States)

    Zheng, Haiyong; Wang, Ruchen; Yu, Zhibin; Wang, Nan; Gu, Zhaorui; Zheng, Bing

    2017-12-28

    Plankton, including phytoplankton and zooplankton, are the main source of food for organisms in the ocean and form the base of marine food chain. As the fundamental components of marine ecosystems, plankton is very sensitive to environment changes, and the study of plankton abundance and distribution is crucial, in order to understand environment changes and protect marine ecosystems. This study was carried out to develop an extensive applicable plankton classification system with high accuracy for the increasing number of various imaging devices. Literature shows that most plankton image classification systems were limited to only one specific imaging device and a relatively narrow taxonomic scope. The real practical system for automatic plankton classification is even non-existent and this study is partly to fill this gap. Inspired by the analysis of literature and development of technology, we focused on the requirements of practical application and proposed an automatic system for plankton image classification combining multiple view features via multiple kernel learning (MKL). For one thing, in order to describe the biomorphic characteristics of plankton more completely and comprehensively, we combined general features with robust features, especially by adding features like Inner-Distance Shape Context for morphological representation. For another, we divided all the features into different types from multiple views and feed them to multiple classifiers instead of only one by combining different kernel matrices computed from different types of features optimally via multiple kernel learning. Moreover, we also applied feature selection method to choose the optimal feature subsets from redundant features for satisfying different datasets from different imaging devices. We implemented our proposed classification system on three different datasets across more than 20 categories from phytoplankton to zooplankton. The experimental results validated that our system

  6. Boronic acids for fluorescence imaging of carbohydrates.

    Science.gov (United States)

    Sun, Xiaolong; Zhai, Wenlei; Fossey, John S; James, Tony D

    2016-02-28

    "Fluorescence imaging" is a particularly exciting and rapidly developing area of research; the annual number of publications in the area has increased ten-fold over the last decade. The rapid increase of interest in fluorescence imaging will necessitate the development of an increasing number of molecular receptors and binding agents in order to meet the demand in this rapidly expanding area. Carbohydrate biomarkers are particularly important targets for fluorescence imaging given their pivotal role in numerous important biological events, including the development and progression of many diseases. Therefore, the development of new fluorescent receptors and binding agents for carbohydrates is and will be increasing in demand. This review highlights the development of fluorescence imaging agents based on boronic acids a particularly promising class of receptors given their strong and selective binding with carbohydrates in aqueous media.

  7. Carbohydrates in pig nutrition - Recent advances

    DEFF Research Database (Denmark)

    Knudsen, Knud Erik Bach; Lærke, Helle Nygaard; Ingerslev, Anne Krog

    2016-01-01

    The dietary carbohydrates are a diverse group of substances with a range of chemical, physical, and physiological properties. The primary chemical classification of carbohydrates is by molecular size (degree of polymerization [DP]), the type of linkage (α or β), and composition of individual...... to their potential for digestion by endogenous enzymes. Carbohydrates are the principal substrates for energy metabolism but also exert a number of other effects throughout the gastrointestinal tract. The starch structure as well as type and levels of DF influence, to a varying degree, the rate of starch digestion...... in the small intestine. Some types of soluble NSP are found to interact with intestinal mucus and produce a layer that significantly delays the transport of lipid digestion products. Potentially, the same may be the case for proteinous compounds. The delay in the transport of the nutrients to the gut...

  8. Assessment of Nuclear Power Plant Impact to the Environment: Effect of Sea Water Temperature Increase on Plankton Population

    International Nuclear Information System (INIS)

    Tjahaja, I P; Pujadi; Supriharyono; Aviati, N; Ruswahyun; Busono, H

    1996-01-01

    Research to study the effect of sea water temperature increase on plankton population had been carried out to predict nuclear power plant impact to the environment. Plankton collected from Jepara waters, Muria Peninsula, was grown on growth medium i.e. sea water enriched with silicate fertilizer. Plankton growth was maintained at temperature varied from 34oC to 46oC and the amount of plankton individu was counted twice a day until it was reduced about 95%. The results showed that the reduction of amount of plankton individu occurred on the medium with temperature above the ambient temperature (34oC). The rate of reduction is linear to the temperature increase. There is no plankton survived at temperature above 40oC for more than 24 hours

  9. Sheldon spectrum and the plankton paradox: two sides of the same coin-a trait-based plankton size-spectrum model.

    Science.gov (United States)

    Cuesta, José A; Delius, Gustav W; Law, Richard

    2018-01-01

    The Sheldon spectrum describes a remarkable regularity in aquatic ecosystems: the biomass density as a function of logarithmic body mass is approximately constant over many orders of magnitude. While size-spectrum models have explained this phenomenon for assemblages of multicellular organisms, this paper introduces a species-resolved size-spectrum model to explain the phenomenon in unicellular plankton. A Sheldon spectrum spanning the cell-size range of unicellular plankton necessarily consists of a large number of coexisting species covering a wide range of characteristic sizes. The coexistence of many phytoplankton species feeding on a small number of resources is known as the Paradox of the Plankton. Our model resolves the paradox by showing that coexistence is facilitated by the allometric scaling of four physiological rates. Two of the allometries have empirical support, the remaining two emerge from predator-prey interactions exactly when the abundances follow a Sheldon spectrum. Our plankton model is a scale-invariant trait-based size-spectrum model: it describes the abundance of phyto- and zooplankton cells as a function of both size and species trait (the maximal size before cell division). It incorporates growth due to resource consumption and predation on smaller cells, death due to predation, and a flexible cell division process. We give analytic solutions at steady state for both the within-species size distributions and the relative abundances across species.

  10. Minimally refined biomass fuel. [carbohydrate-water-alcohol mixture

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, R.K.; Hirschfeld, T.B.

    1981-03-26

    A minimally refined fluid composition, suitable as a fuel mixture and derived from biomass material, is comprised of one or more water-soluble carbohydrates such as sucrose, one or more alcohols having less than four carbons, and water. The carbohydrate provides the fuel source; water-solubilizes the carbohydrate; and the alcohol aids in the combustion of the carbohydrate and reduces the viscosity of the carbohydrate/water solution. Because less energy is required to obtain the carbohydrate from the raw biomass than alcohol, an overall energy savings is realized compared to fuels employing alcohol as the primary fuel.

  11. Hepatocyte heterogeneity in the metabolism of carbohydrates.

    Science.gov (United States)

    Jungermann, K; Thurman, R G

    1992-01-01

    Periportal and perivenous hepatocytes possess different amounts and activities of the rate-generating enzymes of carbohydrate and oxidative energy metabolism and thus different metabolic capacities. This is the basis of the model of metabolic zonation, according to which periportal cells catalyze predominantly the oxidative catabolism of fatty and amino acids as well as glucose release and glycogen formation via gluconeogenesis, and perivenous cells carry out preferentially glucose uptake for glycogen synthesis and glycolysis coupled to liponeogenesis. The input of humoral and nervous signals into the periportal and perivenous zones is different; gradients of oxygen, substrates and products, hormones and mediators and nerve densities exist which are important not only for the short-term regulation of carbohydrate metabolism but also for the long-term regulation of zonal gene expression. The specialization of periportal and perivenous hepatocytes in carbohydrate metabolism has been well characterized. In vivo evidence is provided by the complex metabolic situation termed the 'glucose paradox' and by zonal flux differences calculated on the basis of the distribution of enzymes and metabolites. In vitro evidence is given by the different flux rates determined with classical invasive techniques, e.g. in periportal-like and perivenous-like hepatocytes in cell culture, in periportal- and perivenous-enriched hepatocyte populations and in perfused livers during orthograde and retrograde flow, as well as with noninvasive techniques using miniature oxygen electrodes, e.g. in livers perfused in either direction. Differences of opinion in the interpretation of studies with invasive and noninvasive techniques by the authors are discussed. The declining gradient in oxygen concentrations, the decreasing glucagon/insulin ratio and the different innervation could be important factors in the zonal expression of the genes of carbohydrate-metabolizing enzymes. While it is clear that

  12. Carbohydrates digestion and metabolism in the spiny lobster (Panulirus argus): biochemical indication for limited carbohydrate utilization.

    Science.gov (United States)

    Rodríguez-Viera, Leandro; Perera, Erick; Montero-Alejo, Vivian; Perdomo-Morales, Rolando; García-Galano, Tsai; Martínez-Rodríguez, Gonzalo; Mancera, Juan M

    2017-01-01

    As other spiny lobsters, Panulirus argus is supposed to use preferentially proteins and lipids in energy metabolism, while carbohydrates are well digested but poorly utilized. The aim of this study was to evaluate the effect of dietary carbohydrate level on digestion and metabolism in the spiny lobster P. argus . We used complementary methodologies such as post-feeding flux of nutrients and metabolites, as well as measurements of α-amylase expression and activity in the digestive tract. Lobsters readily digested and absorbed carbohydrates with a time-course that is dependent on their content in diet. Lobster showed higher levels of free glucose and stored glycogen in different tissues as the inclusion of wheat flour increased. Modifications in intermediary metabolism revealed a decrease in amino acids catabolism coupled with a higher use of free glucose as carbohydrates rise up to 20%. However, this effect seems to be limited by the metabolic capacity of lobsters to use more than 20% of carbohydrates in diets. Lobsters were not able to tightly regulate α-amylase expression according to dietary carbohydrate level but exhibited a marked difference in secretion of this enzyme into the gut. Results are discussed to highlight the limitations to increasing carbohydrate utilization by lobsters. Further growout trials are needed to link the presented metabolic profiles with phenotypic outcomes.

  13. Carbohydrates digestion and metabolism in the spiny lobster (Panulirus argus: biochemical indication for limited carbohydrate utilization

    Directory of Open Access Journals (Sweden)

    Leandro Rodríguez-Viera

    2017-11-01

    Full Text Available As other spiny lobsters, Panulirus argus is supposed to use preferentially proteins and lipids in energy metabolism, while carbohydrates are well digested but poorly utilized. The aim of this study was to evaluate the effect of dietary carbohydrate level on digestion and metabolism in the spiny lobster P. argus. We used complementary methodologies such as post-feeding flux of nutrients and metabolites, as well as measurements of α-amylase expression and activity in the digestive tract. Lobsters readily digested and absorbed carbohydrates with a time-course that is dependent on their content in diet. Lobster showed higher levels of free glucose and stored glycogen in different tissues as the inclusion of wheat flour increased. Modifications in intermediary metabolism revealed a decrease in amino acids catabolism coupled with a higher use of free glucose as carbohydrates rise up to 20%. However, this effect seems to be limited by the metabolic capacity of lobsters to use more than 20% of carbohydrates in diets. Lobsters were not able to tightly regulate α-amylase expression according to dietary carbohydrate level but exhibited a marked difference in secretion of this enzyme into the gut. Results are discussed to highlight the limitations to increasing carbohydrate utilization by lobsters. Further growout trials are needed to link the presented metabolic profiles with phenotypic outcomes.

  14. Exponential increase in postprandial blood-glucose exposure with increasing carbohydrate loads using a linear carbohydrate-to-insulin ratio.

    Science.gov (United States)

    Marran, K J; Davey, B; Lang, A; Segal, D G

    2013-04-10

    Postprandial glucose excursions contribute significantly to average blood glucose, glycaemic variability and cardiovascular risk. Carbohydrate counting is a method of insulin dosing that balances carbohydrate load to insulin dose using a fixed ratio. Many patients and current insulin pumps calculate insulin delivery for meals based on a linear carbohydrate-to-insulin relationship. It is our hypothesis that a non-linear relationship exists between the amounts of carbohydrate consumed and the insulin required to cover it. To document blood glucose exposure in response to increasing carbohydrate loads on fixed carbohydrate-to-insulin ratios. Five type 1 diabetic subjects receiving insulin pump therapy with good control were recruited. Morning basal rates and carbohydrate- to-insulin ratios were optimised. A Medtronic glucose sensor was used for 5 days to collect data for area-under-the-curve (AUC) analysis, during which standardised meals of increasing carbohydrate loads were consumed. Increasing carbohydrate loads using a fixed carbohydrate-to-insulin ratio resulted in increasing glucose AUC. The relationship was found to be exponential rather than linear. Late postprandial hypoglycaemia followed carbohydrate loads of >60 g and this was often followed by rebound hyperglycaemia that lasted >6 hours. A non-linear relationship exists between carbohydrates consumed and the insulin required to cover them. This has implications for control of postprandial blood sugars, especially when consuming large carbohydrate loads. Further studies are required to look at the optimal ratios, duration and type of insulin boluses required to cover increasing carbohydrate loads.

  15. Effects of experimental nitrogen fertilization on planktonic metabolism and CO2 flux in a hypereutrophic hardwater lake.

    Directory of Open Access Journals (Sweden)

    Matthew J Bogard

    Full Text Available Hardwater lakes are common in human-dominated regions of the world and often experience pollution due to agricultural and urban effluent inputs of inorganic and organic nitrogen (N. Although these lakes are landscape hotspots for CO2 exchange and food web carbon (C cycling, the effect of N enrichment on hardwater lake food web functioning and C cycling patterns remains unclear. Specifically, it is unknown if different eutrophication scenarios (e.g., modest non point vs. extreme point sources yield consistent effects on auto- and heterotrophic C cycling, or how biotic responses interact with the inorganic C system to shape responses of air-water CO2 exchange. To address this uncertainty, we induced large metabolic gradients in the plankton community of a hypereutrophic hardwater Canadian prairie lake by adding N as urea (the most widely applied agricultural fertilizer at loading rates of 0, 1, 3, 8 or 18 mg N L-1 week-1 to 3240-L, in-situ mesocosms. Over three separate 21-day experiments, all treatments of N dramatically increased phytoplankton biomass and gross primary production (GPP two- to six-fold, but the effects of N on autotrophs plateaued at ~3 mg N L-1. Conversely, heterotrophic metabolism increased linearly with N fertilization over the full treatment range. In nearly all cases, N enhanced net planktonic uptake of dissolved inorganic carbon (DIC, and increased the rate of CO2 influx, while planktonic heterotrophy and CO2 production only occurred in the highest N treatments late in each experiment, and even in these cases, enclosures continued to in-gas CO2. Chemical effects on CO2 through calcite precipitation were also observed, but similarly did not change the direction of net CO2 flux. Taken together, these results demonstrate that atmospheric exchange of CO2 in eutrophic hardwater lakes remains sensitive to increasing N loading and eutrophication, and that even modest levels of N pollution are capable of enhancing autotrophy and CO

  16. The continuous plankton recorder survey: A long-term, basin-scale oceanic time series

    Science.gov (United States)

    Gamble, John C.; Hunt, Harold G.

    1992-01-01

    In the 1920s, before the advent of echo sounders, fishery biologists were greatly concerned with assisting the fisherman to locate schools of pelagic fish. One of the approaches they developed was to relate the distribution of the planktonic food organisms to the presence of the schools of predators such as herring (Clupea harengus). The British planktologist, Alister Hardy, who had already carried out extensive studies on the feeding preferences of herring (Hardy, 1926a), initiated a program to examine the fishermen's contention that herring schools avoided 'green', i.e., phytoplankton-rich, water but could be correlated with high concentrations of zooplankton. This practical program was centered on the use of a specially developed instrument, the 'Plankton Indicator', designed to be used by the fisherman to assist in the search for suitable waters. It had limited success in its main aim but, as a collecting device, it embodied several profoundly important features. It was a simple instrument which was robust enough to be deployed and recovered by the crew of commercial vessels (in this case fishing vessels) while they were underway. The Indicator however, was no more than a high speed net which integrated the plankton over the area of sampling, but Hardy had also become interested in describing the patchiness of planktonic populations. He thus developed the Continuous Plankton Recorder (CPR) where he substituted the fixed filter screen of the Indicator by a continually moving length of silk mesh. The screen traversed at constant speed across the path of the incoming water and the trapped organisms were retained in place by sandwiching beneath an additional second mesh screen. Thus, knowing the speed of the towing vessel and the shooting and hauling positions, the spatial patterns of the plankton could be determined. Hardy took the first CPR to the Antarctic where he used it in the Southern Atlantic (Hardy, 1926b) and later deployed it in the North Sea to make

  17. Contribution of bacterial respiration to plankton respiration from 50°N to 44°S in the Atlantic Ocean

    Science.gov (United States)

    García-Martín, E. E.; Aranguren-Gassis, M.; Hartmann, M.; Zubkov, M. V.; Serret, P.

    2017-11-01

    Marine bacteria play an important role in the global cycling of carbon and therefore in climate regulation. However, the paucity of direct measurements means that our understanding of the magnitude and variability of bacterial respiration in the ocean is poor. Estimations of respiration in the 0.2-0.8 μm size-fraction (considered as bacterial respiration), total plankton community respiration, and the contribution of bacterial respiration to total plankton community respiration were made along two latitudinal transects in the Atlantic Ocean (ca. 50°N-44°S) during 2010 and 2011. Two different methodologies were used: determination of changes in dissolved O2 concentration after standard 24 h dark bottle incubations, and measurements of in vivo reduction of 2-(ρ-iodophenyl)-3-(ρ-nitrophenyl)-5phenyl tetrazolium salt (INT). There was an overall significant correlation (r = 0.44, p community respiration estimated by both methods. Depth-integrated community respiration varied as much as threefold between regions. Maximum rates occurred in waters of the western European shelf and Patagonian shelf, and minimum rates in the North and South oligotrophic gyres. Depth-integrated bacterial respiration followed the same pattern as community respiration. There was a significantly higher cell-specific bacterial respiration in the northern subtropical gyre than in the southern subtropical gyre which suggests that bacterial carbon turnover is faster in the northern gyre. The relationships between plankton respiration and physicochemical and biological variables were different in different years. In general, INTT was correlated to both chlorophyll-a and bacterial abundance, while INT0.2-0.8 was only correlated with bacterial abundance. However, in 2010 INTT and INT0.2-0.8 were also correlated with temperature and primary production while in 2011 they were correlated with nitrate + nitrite concentration. The bacterial contribution to depth integrated community respiration was

  18. A Universal Protocol for Photochemical Covalent Immobilization of Intact Carbohydrates for the Preparation of Carbohydrate Microarrays

    Science.gov (United States)

    Wang, Huibin; Zhang, Yiming; Yuan, Xun; Chen, Yi; Yan, Mingdi

    2010-01-01

    A universal photochemical method has been established for the immobilization of intact carbohydrates and their analogues, and for the fabrication of carbohydrate microarrays. The method features the use of perfluorophenyl azide (PFPA)-modified substrates and the photochemical reaction of surface azido groups with printed carbohydrates. Various aldoses, ketoses, non-reducing sugars such as alditols and their derivatives can be directly arrayed on the PFPA-modified chips. The lectin-recognition ability of arrayed mannose, glucose and their oligo- and polysaccharides were confirmed using surface plasmon resonance imaging and laser-induced fluorescence imaging. PMID:21138274

  19. Influence of Ocean Acidification on a Natural Winter-to-Summer Plankton Succession: First Insights from a Long-Term Mesocosm Study Draw Attention to Periods of Low Nutrient Concentrations.

    Directory of Open Access Journals (Sweden)

    Lennart T Bach

    Full Text Available Every year, the oceans absorb about 30% of anthropogenic carbon dioxide (CO2 leading to a re-equilibration of the marine carbonate system and decreasing seawater pH. Today, there is increasing awareness that these changes-summarized by the term ocean acidification (OA-could differentially affect the competitive ability of marine organisms, thereby provoking a restructuring of marine ecosystems and biogeochemical element cycles. In winter 2013, we deployed ten pelagic mesocosms in the Gullmar Fjord at the Swedish west coast in order to study the effect of OA on plankton ecology and biogeochemistry under close to natural conditions. Five of the ten mesocosms were left unperturbed and served as controls (~380 μatm pCO2, whereas the others were enriched with CO2-saturated water to simulate realistic end-of-the-century carbonate chemistry conditions (~760 μatm pCO2. We ran the experiment for 113 days which allowed us to study the influence of high CO2 on an entire winter-to-summer plankton succession and to investigate the potential of some plankton organisms for evolutionary adaptation to OA in their natural environment. This paper is the first in a PLOS collection and provides a detailed overview on the experimental design, important events, and the key complexities of such a "long-term mesocosm" approach. Furthermore, we analyzed whether simulated end-of-the-century carbonate chemistry conditions could lead to a significant restructuring of the plankton community in the course of the succession. At the level of detail analyzed in this overview paper we found that CO2-induced differences in plankton community composition were non-detectable during most of the succession except for a period where a phytoplankton bloom was fueled by remineralized nutrients. These results indicate: (1 Long-term studies with pelagic ecosystems are necessary to uncover OA-sensitive stages of succession. (2 Plankton communities fueled by regenerated nutrients may be

  20. Influence of Ocean Acidification on a Natural Winter-to-Summer Plankton Succession: First Insights from a Long-Term Mesocosm Study Draw Attention to Periods of Low Nutrient Concentrations

    Science.gov (United States)

    Taucher, Jan; Boxhammer, Tim; Ludwig, Andrea; Achterberg, Eric P.; Algueró-Muñiz, María; Anderson, Leif G.; Bellworthy, Jessica; Büdenbender, Jan; Czerny, Jan; Ericson, Ylva; Esposito, Mario; Fischer, Matthias; Haunost, Mathias; Hellemann, Dana; Horn, Henriette G.; Hornick, Thomas; Meyer, Jana; Sswat, Michael; Zark, Maren; Riebesell, Ulf

    2016-01-01

    Every year, the oceans absorb about 30% of anthropogenic carbon dioxide (CO2) leading to a re-equilibration of the marine carbonate system and decreasing seawater pH. Today, there is increasing awareness that these changes–summarized by the term ocean acidification (OA)–could differentially affect the competitive ability of marine organisms, thereby provoking a restructuring of marine ecosystems and biogeochemical element cycles. In winter 2013, we deployed ten pelagic mesocosms in the Gullmar Fjord at the Swedish west coast in order to study the effect of OA on plankton ecology and biogeochemistry under close to natural conditions. Five of the ten mesocosms were left unperturbed and served as controls (~380 μatm pCO2), whereas the others were enriched with CO2-saturated water to simulate realistic end-of-the-century carbonate chemistry conditions (~760 μatm pCO2). We ran the experiment for 113 days which allowed us to study the influence of high CO2 on an entire winter-to-summer plankton succession and to investigate the potential of some plankton organisms for evolutionary adaptation to OA in their natural environment. This paper is the first in a PLOS collection and provides a detailed overview on the experimental design, important events, and the key complexities of such a “long-term mesocosm” approach. Furthermore, we analyzed whether simulated end-of-the-century carbonate chemistry conditions could lead to a significant restructuring of the plankton community in the course of the succession. At the level of detail analyzed in this overview paper we found that CO2-induced differences in plankton community composition were non-detectable during most of the succession except for a period where a phytoplankton bloom was fueled by remineralized nutrients. These results indicate: (1) Long-term studies with pelagic ecosystems are necessary to uncover OA-sensitive stages of succession. (2) Plankton communities fueled by regenerated nutrients may be more

  1. Particulate carbohydrate and proteins in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sreepada, R.A.; Rivonker, C.U.; Parulekar, A.H.

    /PCHO as a means of estimating plankton nutritional status indicated a severe lack of nitrogen or phosphorus deficiency. However, this ratio may not serve as a true indicator of nutrient deficiency in oligotrophic areas, where non-phytal biomass controls...

  2. An integrated fish-plankton aquaculture system in brackish water.

    Science.gov (United States)

    Gilles, S; Fargier, L; Lazzaro, X; Baras, E; De Wilde, N; Drakidès, C; Amiel, C; Rispal, B; Blancheton, J-P

    2013-02-01

    Integrated Multi-Trophic Aquaculture takes advantage of the mutualism between some detritivorous fish and phytoplankton. The fish recycle nutrients by consuming live (and dead) algae and provide the inorganic carbon to fuel the growth of live algae. In the meanwhile, algae purify the water and generate the oxygen required by fishes. Such mechanism stabilizes the functioning of an artificially recycling ecosystem, as exemplified by combining the euryhaline tilapia Sarotherodon melanotheron heudelotii and the unicellular alga Chlorella sp. Feed addition in this ecosystem results in faster fish growth but also in an increase in phytoplankton biomass, which must be limited. In the prototype described here, the algal population control is exerted by herbivorous zooplankton growing in a separate pond connected in parallel to the fish-algae ecosystem. The zooplankton production is then consumed by tilapia, particularly by the fry and juveniles, when water is returned to the main circuit. Chlorella sp. and Brachionus plicatilis are two planktonic species that have spontaneously colonized the brackish water of the prototype, which was set-up in Senegal along the Atlantic Ocean shoreline. In our system, water was entirely recycled and only evaporation was compensated (1.5% volume/day). Sediment, which accumulated in the zooplankton pond, was the only trophic cul-de-sac. The system was temporarily destabilized following an accidental rotifer invasion in the main circuit. This caused Chlorella disappearance and replacement by opportunist algae, not consumed by Brachionus. Following the entire consumption of the Brachionus population by tilapias, Chlorella predominated again. Our artificial ecosystem combining S. m. heudelotii, Chlorella and B. plicatilis thus appeared to be resilient. This farming system was operated over one year with a fish productivity of 1.85 kg/m2 per year during the cold season (January to April).

  3. Biofilm vs. Planktonic Lifestyle: Consequences for Pesticide 2,4-D Metabolism by Cupriavidus necator JMP134

    Directory of Open Access Journals (Sweden)

    Thomas Z. Lerch

    2017-05-01

    Full Text Available The development of bacterial biofilms in natural environments may alter important functions, such as pollutant bioremediation by modifying both the degraders' physiology and/or interactions within the matrix. The present study focuses on the influence of biofilm formation on the metabolism of a pesticide, 2,4-dichlorophenoxyacetic acid (2,4-D, by Cupriavidus necator JMP134. Pure cultures were established in a liquid medium with 2,4-D as a sole carbon source with or without sand grains for 10 days. Bacterial numbers and 2,4-D concentrations in solution were followed by spectrophotometry, the respiration rate by gas chromatography and the surface colonization by electron microscopy. In addition, isotopic techniques coupled with Fatty Acid Methyl Ester (FAME profiling were used to determine possible metabolic changes. After only 3 days, approximately 80% of the cells were attached to the sand grains and microscopy images showed that the porous medium was totally clogged by the development of a biofilm. After 10 days, there was 25% less 2,4-D in the solution in samples with sand than in control samples. This difference was due to (1 a higher (+8% mineralization of 2,4-D by sessile bacteria and (2 a retention (15% of 2,4-D in the biofilm matrix. Besides, the amount of carbohydrates, presumably constituting the biofilm polysaccharides, increased by 63%. Compound-specific isotope analysis revealed that the FAME isotopic signature was less affected by the biofilm lifestyle than was the FAME composition. These results suggest that sessile bacteria differ more in their anabolism than in their catabolism compared to their planktonic counterparts. This study stresses the importance of considering interactions between microorganisms and their habitat when studying pollutant dynamics in porous media.

  4. Effect of climate and environmental changes on plankton biodiversity and bigeochemical cycles of the Dongsha (Pratas) Atoll, South China Sea

    Science.gov (United States)

    Lo, Wen-tseng; Hsu, Pei-Kai; Hunag, Jia-Jang; Wang, Yu-Huai

    2013-04-01

    Dongsha (Pratas) Atoll, the so called "Pearl Crown of South China Sea", is a well-developed atoll with a total area of 80000 hectares. It possesses various ecosystems and has very high biodiversity, but it is very sensitive to climate change and physical processes. According to our investigation within the shallow semi-enclosed atoll in April, July, and October, 2011 (i.e., spring, summer, and autumn, respectively), we found that plankton assemblages and hydrographical conditions exhibited clear seasonal and spatial variations. Colder and higher salinity water was observed in April, while warmer water in July and lower salinity water in October, respectively. Nutrient concentration within the atoll was similar to that of the oligotrophic South China Sea waters and seemed to be in nitrogen-limit situation, while the distribution pattern of DOC and POC was mainly attributed to Chla and imported detritus matters. Carbon deposition flux also showed significant seasonal changes, but POC/PN value was near Redfield ratio, implying mostly due to biogenic factors; however it could still be classified as a typical coral ecosystem, since CaCO3 sinking flux generally was 30 times higher than that of organic matter. Plankton biodiversity was quite high in the atoll, and preformed apparent seasonal succession; in total, 82 phytoplankton species and 67 copepod species were recorded; furthermore, crab zoea (17.3% of the total zooplankton by number), fish eggs (12.5%), and shrimp larvae (4.2%), were relatively abundant in zooplankton community, revealed that atoll might be a good hatching ground. We deduced that the seasonal patterns of chemical and biological variables were mainly influenced by monsoons and precipitation, while small scales of temporal and spatial variations could be ascribed to internal wave and tide in this study area.

  5. Carbohydrates and gibberellins relationship in potato tuberization

    Czech Academy of Sciences Publication Activity Database

    Ševčíková, H.; Mašková, P.; Tarkowská, Danuše; Mašek, T.; Lipavská, H.

    2017-01-01

    Roč. 214, JUL (2017), s. 53-63 ISSN 0176-1617 R&D Projects: GA ČR GA14-34792S Institutional support: RVO:61389030 Keywords : Carbohydrate distribution * Gibberellin * Photoautotrophic cultivation * Potato * Tuberization Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Plant sciences, botany Impact factor: 3.121, year: 2016

  6. Accumulation pattern of total nonstructural carbohydrate in ...

    African Journals Online (AJOL)

    Umukoro

    1977-09-09

    Sep 9, 1977 ... 1Instituto Nacional de Tecnología Agropecuaria (INTA), EEA Famaillá, Argentina. 2Department of Plant Sciences, University of California Davis, CA, USA. Accepted 17 October, 2012. The pattern of total nonstructural carbohydrate (TNC) accumulation in strawberry (Fragaria ananassa. Duch.) nursery ...

  7. Crystallization of carbohydrate oxidase from Microdochium nivale

    Czech Academy of Sciences Publication Activity Database

    Dušková, Jarmila; Dohnálek, Jan; Skálová, Tereza; Ostergaard, L. H.; Fuglsang, C. C.; Kolenko, Petr; Štěpánková, Andrea; Hašek, Jindřich

    2009-01-01

    Roč. 65, č. 6 (2009), s. 638-640 ISSN 1744-3091 R&D Projects: GA AV ČR IAA500500701; GA ČR GA305/07/1073 Institutional research plan: CEZ:AV0Z40500505 Keywords : carbohydrate oxidase * crystallization * data processing Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.551, year: 2009

  8. Nutrient and carbohydrate partitioning in sorghum stover

    International Nuclear Information System (INIS)

    Powell, J.M.; Hons, F.M.; McBee, G.G.

    1991-01-01

    Sorghum [Sorghum bicolor (L.) Moench] stover has been demonstrated to be a potential biomass energy source. Complete aboveground crop removal, however, can result in soil degradation. Differential dry matter, nutrient, and carbohydrate partitioning by sorghum cultivars may allow management strategies that return certain parts to the field while removing other portions for alternative uses, such as energy production. A field study was conducted to determine N,P,K, nonstructural carbohydrate, cellulose hemicellulose, and lignin distributions in stover of three diverse sorghum cultivars of differing harvest indices. Determinations were based on total vegetative biomass; total blades; total stalks; and upper middle, and lower blades and stalks. Concentrations of N and P were higher in blades than stalks and generally declines from upper to lower stover parts. Large carbohydrate and lignin concentration differences were observed on the basis of cultivar and stover part. Greater nutrient partitioning to the upper third of the intermediate and forage-type sorghum stovers was observed as compared to the conventional grain cultivar. Stover carbohydrates for all cultivars were mainly contained in the lower two-thirds of the stalk fraction. A system was proposed for returning upper stover portion to soil, while removing remaining portions for alternative uses

  9. Saturated fat, carbohydrates and cardiovascular disease

    NARCIS (Netherlands)

    Kuipers, R. S.; de Graaf, D. J.; Luxwolda, M. F.; Muskiet, M. H. A.; Dijck-Brouwer, D. A. J.; Muskiet, F. A. J.

    The dietary intake of saturated fatty acids (SAFA) is associated with a modest increase in serum total cholesterol, but not with cardiovascular disease (CVD). Replacing dietary SAFA with carbohydrates (CHO), notably those with a high glycaemic index, is associated with an increase in CVD risk in

  10. Profiling of carbohydrate polymers in biotechnology using ...

    African Journals Online (AJOL)

    The analysis of carbohydrate polymers is very demanding and challenging because of the similar physical and chemical properties they possess. Enzymatic hydrolysis is employed to cleave the polymers. The use of enzymes in analytical chemistry requires an analytical system that has on-line capability, is fast, ...

  11. Radiation chemistry of carbohydrates, ch. 5

    International Nuclear Information System (INIS)

    Dauphin, J.F.; Saint-Lebe, L.R.

    1977-01-01

    The physical and chemical changes undergone by carbohydrates at irradiation are reviewed. The discussion includes the irradiation of pure sugars (low molecular weight sugars and derivatives in the solid state or in solution; polysaccharides) as well as the irradiation of simple mixtures containing a given sugar, emphasizing the irradiation of foodstuffs containing one or more sugars

  12. Carbohydrates in Colobanthus quitensis and Deschampsia antarctica

    Directory of Open Access Journals (Sweden)

    Agnieszka I. Piotrowicz-Cieślak

    2011-01-01

    Full Text Available Eight to nineteen ethanol-soluble carbohydrate components were identified in vegetative tissues of Colobanthus quitensis and Deschampsia antarctica. The analysed carbohydrates included: monosaccharides, cyclitols, galactosyl cyclitols, raffinose family oligosaccharides, lichnose family oligosaccharides, kestose family oligosaccharides. The analysed vegetative tissues accumulated from 447 to 139 mg/g d.m. soluble carbohydrates in Colobanthus quitensis, Deschampsia antarctica respectively. The raffinose family oligosaccharides constituted 53.3% in Colobanthus quitensis of the identified soluble carbohydrate component pool. Vegetative tissues accumulated starch in Colobanthus quitensis 20.6 mg/g d.m. and 261.6 mg/g d.m. in Deschampsia antarctica. Anatomical and ultrastructural observations of vegetative part of Colobanthus quitensis and Deschmpsia antarctica revealed the presence of various ergastic materials in intercellular spaces, cell walls and protoplasts. Various parts of these plants contain insoluble, PAS positive polysaccharides in intercellular spaces and in cell walls. Chloroplasts of analysed tissues contained starch. Less starch was visible in young, growing parts of shoots of Colobanthus quitensis and Deschmpsia antarctica, more starch appears in mature, differentiated parts.

  13. Dissolved carbohydrate in the central Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Dhople, V.M.; Bhosle, N.B.

    with chlorophyll a (P 0.001) and phaeopigments (P 0.001) suggesting its release from the former and zooplankton grazing in the latter. Inverse correlations with dissolved oxygen, phosphate and nitrate indicated the possibility of the release of carbohydrate from...

  14. Accumulation pattern of total nonstructural carbohydrate in ...

    African Journals Online (AJOL)

    The pattern of total nonstructural carbohydrate (TNC) accumulation in strawberry (Fragaria ananassa Duch.) nursery runner plants, cv. eCamarosaf, was determined for three growing seasons. Plant growth and fruit production patterns were also evaluated. The experiments were carried out on plants propagated in high ...

  15. STICS: surface-tethered iterative carbohydrate synthesis.

    Science.gov (United States)

    Pornsuriyasak, Papapida; Ranade, Sneha C; Li, Aixiao; Parlato, M Cristina; Sims, Charles R; Shulga, Olga V; Stine, Keith J; Demchenko, Alexei V

    2009-04-14

    A new surface-tethered iterative carbohydrate synthesis (STICS) technology is presented in which a surface functionalized 'stick' made of chemically stable high surface area porous gold allows one to perform cost efficient and simple synthesis of oligosaccharide chains; at the end of the synthesis, the oligosaccharide can be cleaved off and the stick reused for subsequent syntheses.

  16. DETERMINATION OF CARBOHYDRATE AND β-CAROTENE ...

    African Journals Online (AJOL)

    DR. AMINU

    A sample of each vegetable was washed and ground to a fine pulp using pestle and mortar. The operation was done under dim light to reduce the rate of carotene oxidation contained in them. One gramme (1g) and 10g of macerated sample were weighed using Metler PT balance for carbohydrate and β-carotene analysis ...

  17. Particulate carbohydrates in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Nandakumar, K.; Venkat, K.

    Particulate matter collected from 77 water samples over a 3000 m water column was analyzed for particulate carbohydrates (PCHO). PCHO in the surface waters ranged from 43 to 143 mu g.l-1, and below 250 m it was 16.PCHO showed large variations at all...

  18. The inverted trophic cascade in tropical plankton communities: impacts of exotic fish in the Middle Rio Doce lake district, Minas Gerais, Brazil A cascata trófica invertida em comunidades planctônicas tropicais: impactos da introdução de peixes exóticos no distrito de lagos do médio rio Doce, MG

    Directory of Open Access Journals (Sweden)

    RM. Pinto-Coelho

    2008-11-01

    Full Text Available The present study deals with the ecological impacts of the introduction of two alien species of piscivorous fish in several lakes of the Middle Rio Doce lake district in Minas Gerais, Brazil. It was demonstrated that these effects were not restricted only to the fish community. The introduction of the predatory red piranha Pygocentrus nattereri and the tucunaré Cichla cf. ocellaris caused not only a sharp decrease in the number of native fish species, but also major shifts in other trophic levels. Just after the fish were introduced, most lakes began to show conspicuous changes in phytoplankton species composition, in which Cyanophyceae gradually came to dominate. The zooplankton community lost several species, and in some cases, such as Lake Carioca, all the cladoceran species disappeared. On the other hand, invertebrate predators, represented by the dipteran Chaoboridae, boomed in the lake, with higher densities of exotic species, probably as a result of the "ecological release" by reduction of the original fish fauna. There was a general trend of species loss in different trophic levels. All these changes are apparently associated with decreases in water quality. The present situation in these lakes demands new approaches to the management and conservation of these ecosystems.O presente estudo trata dos impactos ecológicos da introdução de duas espécies invasoras de peixes piscívoros em diversos lagos da região lacustre do médio rio Doce em Minas Gerais, Brasil. Demonstrou-se que estes efeitos não se restringiram às comunidade de peixes. A introdução dos predadores Pygocentrus nattereri (piranha-vermelha e Cichla cf. ocelaris (tucunaré não só causou uma forte redução no número de espécies de peixes nativos, como também mudanças nos níveis tróficos inferiores. Pouco depois das introduções, a maioria dos lagos começou a mostrar alterações na comunidade fitoplanctônica, tais como o aparecimento da dominância de

  19. Cell surface carbohydrates as prognostic markers in human carcinomas

    DEFF Research Database (Denmark)

    Dabelsteen, Erik

    1996-01-01

    Tumour development is usually associated with changes in cell surface carbohydrates. These are often divided into changes related to terminal carbohydrate structures, which include incomplete synthesis and modification of normally existing carbohydrates, and changes in the carbohydrate core...... structure. The latter includes chain elongation of both glycolipids and proteins, increased branching of carbohydrates in N-linked glycoproteins, and blocked synthesis of carbohydrates in O-linked mucin-like glycoproteins. In mature organisms, expression of distinct carbohydrates is restricted to specific...... cell types; within a given tissue, variation in expression may be related to cell maturation. Tumour-associated carbohydrate structures often reflect a certain stage of cellular development; most of these moieties are structures normally found in other adult or embryonic tissues. There is no unique...

  20. High throughput screening of starch structures using carbohydrate microarrays

    DEFF Research Database (Denmark)

    Tanackovic, Vanja; Rydahl, Maja Gro; Pedersen, Henriette Lodberg

    2016-01-01

    In this study we introduce the starch-recognising carbohydrate binding module family 20 (CBM20) from Aspergillus niger for screening biological variations in starch molecular structure using high throughput carbohydrate microarray technology. Defined linear, branched and phosphorylated...

  1. Mixed drink increased carbohydrate oxidation but not performance ...

    African Journals Online (AJOL)

    Kathryn van Boom

    ... carbohydrate intake is hypothesised to provide additional substrate for oxidation[3] ... performance is attained when a multiple carbohydrate drink is ingested. ..... and often intense exercise, such as can be seen in events such as the Tour de ...

  2. Planktonic cyanobacteria of the tropical karstic lake Lagartos from the Yucatan Peninsula, Mexico.

    Science.gov (United States)

    Valadez, Francisco; Rosiles-González, Gabriela; Almazán-Becerril, Antonio; Merino-Ibarra, Martin

    2013-06-01

    The tropical karstic lakes on the Mexican Caribbean Sea coast are numerous. However, there is an enormous gap of knowledge about their limnological conditions and micro-algae communities. In the present study, surface water samples were collected monthly from November 2007 to September 2008 to provide taxonomical composition and biovolume of planktonic cyanobacteria of the lake Lagartos from State of Quintana Roo, Mexico. Water temperature, pH, conductivity, salinity, soluble reactive phosphorus (SRP), dissolved inorganic nitrogen (DIN), and soluble reactive silica (SRSi) levels were also analyzed. A total of 22 species were identified. Chroococcales and Oscillatoriales dominated the phytoplankton assemblages during the study period. Chroococcus pulcherrimus, Coelosphaerium confertum, Cyanodyction iac, Phormidium pachydermaticum and Planktolyngbya contorta were recorded for the first time in Mexico. A surplus of DIN (mean value of 42.7 microM) and low concentrations of SRP (mean value of 1.0 microM) promoted the enhanced growth and bloom formation of cyanobacteria. The mean biovolume was 3.22 x 10(8) microm3/mL, and two biovolume peaks were observed; the first was dominated by Microcystis panniformis in November 2007 (7.40 x 10(8) microm3/mL), and the second was dominated by Oscillatoriaprinceps in April 2008 (6.55 x 10(8) microm3/mL). Water quality data, nitrates enrichment, and trophic state based on biovolume, indicated that Lagartos is a hyposaline, secondarily phosphorus-limited, and eutrophic lake, where the cyanobacteria flora was composed mainly by non-heterocystous groups.

  3. Planktonic Cyanobacteria of the tropical karstic lake Lagartos from the Yucatan Peninsula, Mexico

    Directory of Open Access Journals (Sweden)

    Francisco Valadez

    2013-06-01

    Full Text Available The tropical karstic lakes on the Mexican Caribbean Sea coast are numerous. However, there is an enormous gap of knowledge about their limnological conditions and micro-algae communities. In the present study, surface water samples were collected monthly from November 2007 to September 2008 to provide taxonomical composition and biovolume of planktonic cyanobacteria of the lake Lagartos from State of Quintana Roo, Mexico. Water temperature, pH, conductivity, salinity, soluble reactive phosphorus (SRP, dissolved inorganic nitrogen (DIN, and soluble reactive silica (SRSi levels were also analyzed. A total of 22 species were identified. Chroococcales and Oscillatoriales dominated the phytoplankton assemblages during the study period. Chroococcus pulcherrimus, Coelosphaerium confertum, Cyanodyction iac, Phormidium pachydermaticum and Planktolyngbya contorta were recorded for the first time in Mexico. A surplus of DIN (mean value of 42.7µM and low concentrations of SRP (mean value of 1.0µM promoted the enhanced growth and bloom formation of cyanobacteria. The mean biovolume was 3.22X10(8µm³/mL, and two biovolume peaks were observed; the first was dominated by Microcystis panniformis in November 2007 (7.40X10(8µm³/mL, and the second was dominated by Oscillatoria princeps in April 2008 (6.55X10(8µm³/mL. Water quality data, nitrates enrichment, and trophic state based on biovolume, indicated that Lagartos is a hyposaline, secondarily phosphorus-limited, and eutrophic lake, where the cyanobacteria flora was composed mainly by non-heterocystous groups.

  4. Factors driving the seasonal distribution of planktonic and epiphytic ciliates in a eutrophicated Mediterranean Lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Dhib, Amel [Université de Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS 6249 (France); Institut National des Sciences et Technologies de la Mer (INSTM), Laboratoire Milieu Marin, Centre la Goulette (Tunisia); Brahim, Mounir Ben; Ziadi, Boutheina; Akrout, Fourat; Turki, Souad [Institut National des Sciences et Technologies de la Mer (INSTM), Laboratoire Milieu Marin, Centre la Goulette (Tunisia); Aleya, Lotfi [Université de Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS 6249 (France)

    2013-09-15

    Highlights: • Distribution of planktonic and epiphytic ciliates at five stations in Ghar El Melh Lagoon. • 28 planktonic ciliates were identified with spring-early autumn peaks. • 4 epiphytic ciliates of the seagrass Ruppia cirrhosa were recorded with high density. • Significant correlations were found between ciliate assemblages, environmental factors and harmful dinoflagellates. -- Abstract: We studied the distribution of planktonic and epiphytic ciliates coupled with environmental factors and microalgae abundance at five stations in Ghar El Melh Lagoon (Tunisia). Planktonic ciliates were monitored for a year and epiphytic ciliates were sampled during summer 2011 in concordance with the proliferation of the seagrass Ruppia cirrhosa. Ciliate assemblage was largely dominated by Spirotrichea followed respectively by Tintinnida of and Strombidiida. No significant difference was found in the distribution of ciliate species among the stations. Redundancy analysis indicates that abiotic factors (temperature and nutriments) have a significant effect on the dynamics of certain ciliates. For epiphytic ciliates, 4 species were identified: Tintinnopsis campanula, Aspidisca sp., Strombidium acutum and Amphorides amphora. Based on PERMANOVA analyses, ciliates exhibit significant correlations among months and stations. According to ACP, epiphyte distribution follows roughly those of R. cirrhosa and pH. Significant correlations were found between harmful dinoflagellates and both planktonic and epiphytic ciliates.

  5. Factors driving the seasonal distribution of planktonic and epiphytic ciliates in a eutrophicated Mediterranean Lagoon

    International Nuclear Information System (INIS)

    Dhib, Amel; Brahim, Mounir Ben; Ziadi, Boutheina; Akrout, Fourat; Turki, Souad; Aleya, Lotfi

    2013-01-01

    Highlights: • Distribution of planktonic and epiphytic ciliates at five stations in Ghar El Melh Lagoon. • 28 planktonic ciliates were identified with spring-early autumn peaks. • 4 epiphytic ciliates of the seagrass Ruppia cirrhosa were recorded with high density. • Significant correlations were found between ciliate assemblages, environmental factors and harmful dinoflagellates. -- Abstract: We studied the distribution of planktonic and epiphytic ciliates coupled with environmental factors and microalgae abundance at five stations in Ghar El Melh Lagoon (Tunisia). Planktonic ciliates were monitored for a year and epiphytic ciliates were sampled during summer 2011 in concordance with the proliferation of the seagrass Ruppia cirrhosa. Ciliate assemblage was largely dominated by Spirotrichea followed respectively by Tintinnida of and Strombidiida. No significant difference was found in the distribution of ciliate species among the stations. Redundancy analysis indicates that abiotic factors (temperature and nutriments) have a significant effect on the dynamics of certain ciliates. For epiphytic ciliates, 4 species were identified: Tintinnopsis campanula, Aspidisca sp., Strombidium acutum and Amphorides amphora. Based on PERMANOVA analyses, ciliates exhibit significant correlations among months and stations. According to ACP, epiphyte distribution follows roughly those of R. cirrhosa and pH. Significant correlations were found between harmful dinoflagellates and both planktonic and epiphytic ciliates

  6. Linking the planktonic and benthic habitat: genetic structure of the marine diatom Skeletonema marinoi.

    Science.gov (United States)

    Godhe, Anna; Härnström, Karolina

    2010-10-01

    Dormant life stages are important strategies for many aquatic organisms. The formation of resting stages will provide a refuge from unfavourable conditions in the water column, and their successive accumulation in the benthos will constitute a genetic reservoir for future planktonic populations. We have determined the genetic structure of a common bloom-forming diatom, Skeletonema marinoi, in the sediment and the plankton during spring, summer and autumn two subsequent years (2007-2009) in Gullmar Fjord on the Swedish west coast. Eight polymorphic microsatellite loci were used to assess the level of genetic differentiation and the respective gene diversity of the two different habitats. We also determined the degree of genetic differentiation between the seed banks inside the fjord and the open sea. The results indicate that Gullmar Fjord has one dominant endogenous population of S. marinoi, which is genetically differentiated from the open sea population. The fjord population is encountered in the plankton and in the sediment. Shifts from the dominant population can happen, and in our study, two genetically differentiated plankton populations, displaying reduced genetic diversity, occurred in September 2007 and 2008. Based on our results, we suggest that sill fjords maintain local long-lived and well-adapted protist populations, which continuously shift between the planktonic and benthic habitats. Intermittently, short-lived and mainly asexually reproducing populations can replace the dominant population in the water column, without influencing the genetic structure of the benthic seed bank. © 2010 Blackwell Publishing Ltd.

  7. Planktonic foraminifera in the Arctic: potentials and issues regarding modern and quaternary populations

    International Nuclear Information System (INIS)

    Eynaud, Frederique

    2011-01-01

    Calcareous microfossils are widely used by paleoceanographers to investigate past sea-surface hydrology. Among these microfossils, planktonic foraminifera are probably the most extensively used tool (e.g. [1] for a review), as they are easy to extract from the sediment and can also be used for coupled geochemical (e.g; δ 18 O, δ 13 C, Mg/Ca) and paleo-ecological investigations. Planktonic foraminifera are marine protists, which build a calcareous shell made of several chambers which reflect in their chemistry the properties of the ambient water-masses. Planktonic foraminifera are known to thrive in various habitats, distributed not only along a latitudinal gradient, but also along different water-depth intervals within surface waters (0-1000 m). Regarding their biogeographical distribution, planktonic foraminifera assemblages therefore mirror different water-masses properties, such as temperature, salinity and nutrient content of the surface water in which they live. The investigation of the specific composition of a fossil assemblage (relative abundances) is therefore a way to empirically obtain (paleo)information on past variations of sea-surface hydrological parameters. This paper focuses on the planktonic foraminifera record from the Arctic domain. This polar region records peculiar sea-surface conditions, with the influence of nearly perennial sea-ice cover development. This has strong impact on living foraminifera populations and on the preservation of their shells in the underlying sediments.

  8. Planktonic foraminifera in the Arctic: potentials and issues regarding modern and quaternary populations

    Energy Technology Data Exchange (ETDEWEB)

    Eynaud, Frederique, E-mail: f.eynaud@epoc.u-bordeaux1.fr [Universite Bordeaux I, Laboratoire EPOC (Environnements et Paleoenvironnements OCeaniques), UMR CNRS 5805, Avenue des facultes, 33405 Talence cedex - France (France)

    2011-05-15

    Calcareous microfossils are widely used by paleoceanographers to investigate past sea-surface hydrology. Among these microfossils, planktonic foraminifera are probably the most extensively used tool (e.g. [1] for a review), as they are easy to extract from the sediment and can also be used for coupled geochemical (e.g; {delta}{sup 18}O, {delta}{sup 13}C, Mg/Ca) and paleo-ecological investigations. Planktonic foraminifera are marine protists, which build a calcareous shell made of several chambers which reflect in their chemistry the properties of the ambient water-masses. Planktonic foraminifera are known to thrive in various habitats, distributed not only along a latitudinal gradient, but also along different water-depth intervals within surface waters (0-1000 m). Regarding their biogeographical distribution, planktonic foraminifera assemblages therefore mirror different water-masses properties, such as temperature, salinity and nutrient content of the surface water in which they live. The investigation of the specific composition of a fossil assemblage (relative abundances) is therefore a way to empirically obtain (paleo)information on past variations of sea-surface hydrological parameters. This paper focuses on the planktonic foraminifera record from the Arctic domain. This polar region records peculiar sea-surface conditions, with the influence of nearly perennial sea-ice cover development. This has strong impact on living foraminifera populations and on the preservation of their shells in the underlying sediments.

  9. Marine plankton as an indicator of low-level radionuclide contamination in the Southern Ocean

    International Nuclear Information System (INIS)

    Marsh, K.V.; Buddemeier, R.W.

    1984-07-01

    We have initiated an investigation of the utility of marine plankton as bioconcentrating samplers of low-level marine radioactivity in the southern hemisphere. A literature review shows that both freshwater and marine plankton have trace element and radionuclide concentration factors (relative to water) of up to 10 4 . In the years 1956-1958, considerable work was done on the accumulation and distribution of a variety of fission and activation products produced by the nuclear tests in the Marshall Islands. Since then, studies have largely been confined to a few selected radionuclides, and by far most of this work has been done in the northern hemisphere. We participated in Operation Deepfreeze 1981, collecting 32 plankton samples from the U.S. Coast Guard Cutter Glacier on its Antarctic cruise, while Battelle Pacific Northwest Laboratories concurrently sampled air, water, rain and fallout. We were able to measure concentrations of the naturally occurring radionuclides 7 Be, 40 K and the U and th series, and we believe that we have detected low levels of 144 Ce and 95 Nb in seven samples ranging as far south as 68 0 . There is a definite association between the radionuclide content of plankton and air filters, suggesting that aerosol resuspension of marine radioactivity may be occurring. Biological identification of the plankton suggests a possible correlation between radionuclide concentration and foraminifera content of the samples. 38 references, 7 figures, 3 tables

  10. Chemoselective Reactions for the Synthesis of Glycoconjugates from Unprotected Carbohydrates

    DEFF Research Database (Denmark)

    Villadsen, Klaus; Martos Maldonado, Manuel Cristo; Jensen, Knud Jørgen

    2017-01-01

    Glycobiology is the comprehensive biological investigation of carbohydrates. The study of the role and function of complex carbohydrates often requires the attachment of carbohydrates to surfaces, their tagging with fluorophores, or their conversion into natural or non-natural glycoconjugates......, such as glycopeptides or glycolipids. Glycobiology and its “omics”, glycomics, require easy and robust chemical methods for the construction of these glycoconjugates. This review gives an overview of the rapidly expanding field of chemical reactions that selectively convert unprotected carbohydrates...

  11. Renewable Hydrogen Carrier - Carbohydrate: Constructing the Carbon-Neutral Carbohydrate Economy

    Science.gov (United States)

    2011-01-31

    combinations have been investigated for the production of hydrogen from biomass carbohydrate. Chemical catalysis approaches include pyrolysis [19...temperature. High fructose corn syrup, low-cost sucrose replacement, is made by stabilized glucose isomerase, which can work at ~60 °C for even about two...gasoline, vegetable oil vs. biodiesel, corn kernels vs. ethanol [31,109]. Given a price of $0.18/kg carbohydrate (i.e., $10.6/GJ) [2,44], the hydrogen

  12. Activities of Fluconazole, Caspofungin, Anidulafungin, and Amphotericin B on Planktonic and Biofilm Candida Species Determined by Microcalorimetry

    Science.gov (United States)

    Maiolo, Elena Maryka; Furustrand Tafin, Ulrika; Borens, Olivier

    2014-01-01

    We investigated the activities of fluconazole, caspofungin, anidulafungin, and amphotericin B against Candida species in planktonic form and biofilms using a highly sensitive assay measuring growth-related heat production (microcalorimetry). C. albicans, C. glabrata, C. krusei, and C. parapsilosis were tested, and MICs were determined by the broth microdilution method. The antifungal activities were determined by isothermal microcalorimetry at 37°C in RPMI 1640. For planktonic Candida, heat flow was measured in the presence of antifungal dilutions for 24 h. Candida biofilm was formed on porous glass beads for 24 h and exposed to serial dilutions of antifungals for 24 h, and heat flow was measured for 48 h. The minimum heat inhibitory concentration (MHIC) was defined as the lowest antifungal concentration reducing the heat flow peak by ≥50% (≥90% for amphotericin B) at 24 h for planktonic Candida and at 48 h for Candida biofilms (measured also at 24 h). Fluconazole (planktonic MHICs, 0.25 to >512 μg/ml) and amphotericin B (planktonic MHICs, 0.25 to 1 μg/ml) showed higher MHICs than anidulafungin (planktonic MHICs, 0.015 to 0.5 μg/ml) and caspofungin (planktonic MHICs, 0.125 to 0.5 μg/ml). Against Candida species in biofilms, fluconazole's activity was reduced by >1,000-fold compared to its activity against the planktonic counterparts, whereas echinocandins and amphotericin B mainly preserved their activities. Fluconazole induced growth of planktonic C. krusei at sub-MICs. At high concentrations of caspofungin (>4 μg/ml), paradoxical growth of planktonic C. albicans and C. glabrata was observed. Microcalorimetry enabled real-time evaluation of antifungal activities against planktonic and biofilm Candida organisms. It can be used in the future to evaluate new antifungals and antifungal combinations and to study resistant strains. PMID:24566186

  13. The effect of stereochemistry on carbohydrate hydration in aqueous solutions

    NARCIS (Netherlands)

    Galema, Saskia Alexandra

    1992-01-01

    Although-carbohydrates are widely used, not much is known about the stereochemical aspects of hydration of carbohydrates. For D-aldohexoses, for example, there are eight different stereoisomers. Just how the hydroxy topology of a carbohydrate molecule influences the hydration behaviour in water is

  14. A critical review of low-carbohydrate diets in people with Type 2 diabetes.

    Science.gov (United States)

    van Wyk, H J; Davis, R E; Davies, J S

    2016-02-01

    The efficacy of low-carbohydrate diets (LCD) in people with Type 2 diabetes has divided the nutrition community. This review seeks to re-examine the available data to clarify understanding. A comprehensive search of databases was used to identify meta-analyses of LCD in Type 2 diabetes. To improve the quality of the studies analysed, the following inclusion criteria were applied: randomized control trials ≥ 4 weeks in people aged > 18 years with Type 2 diabetes; a carbohydrate intake ≤ 45% of total energy intake per day; and a dietary intake assessment at the end of the study. The resulting studies were subjected to a thematic analysis. Nine meta-analyses were identified containing 153 studies. Twelve studies met our amended inclusion criteria. There were no significant differences in metabolic markers, including glycaemic control, between the two diets, although weight loss with a LCD was greater in one study. Carbohydrate intake at 1 year in very LCD (diets was as little as 8 g/day of carbohydrates. Total energy intake remains the dietary predictor of body weight. A LCD appears no different from a high-carbohydrate diet in terms of metabolic markers and glycaemic control. Very LCDs may not be sustainable over a medium to longer term as carbohydrate intake in diets within studies often converged toward a more moderate level. The variable quality of studies included in earlier meta-analyses likely explains the previous inconsistent findings between meta-analyses. © 2015 The Authors. Diabetic Medicine © 2015 Diabetes UK.

  15. Mesh size effects on assessments of planktonic hydrozoan abundance and assemblage structure

    Science.gov (United States)

    Nogueira Júnior, Miodeli; Pukanski, Luis Eduardo de M.; Souza-Conceição, José M.

    2015-04-01

    The choice of appropriate mesh-size is paramount to accurately quantify planktonic assemblages, however there is no such information available for hydrozoans. Here planktonic hydrozoan abundance and assemblage structure were compared using 200 and 500 μm meshes at Babitonga estuary (S Brazil), throughout a year cycle. Species richness and Shannon-Wiener diversity were higher in the 200 μm mesh, while evenness was typically higher in the 500 μm. Assemblage structure was significantly different between meshes (PERMANOVA, P 8 mm in October. These results suggest that both meshes have their drawbacks and the best choice would depend on the objectives of each study. Nevertheless species richness, total abundances and most taxa were better represented by the 200 μm mesh, suggesting that it is more appropriate to quantitatively sample planktonic hydrozoan assemblages.

  16. Pemanfaatan Plankton sebagai Sumber Makanan Ikan Bandeng di Waduk Ir. H. Juanda, Jawa Barat

    Directory of Open Access Journals (Sweden)

    Deden Ibnu Aqil

    2016-03-01

    Full Text Available Introducing of Milkfish (Chanos chanos was aimed to utilize natural food from plankton that were abundant in Ir. H. Juanda Reservoir, West Java. This research aimed to know plankton utilization by Milkfish in Ir. H. Juanda Reservoir, West Java. The research was conducted from February to July 2010 at 4 stations of sampling which representing the reservoir condition. The fishes collected based on the catch of fishermen. The sample was analyzed in physiology laboratory of Center Research for Limnology. The result of this research showed that the main food were plankton 43%, detritus 46%, and complement food were vegetation 11%. The domination food from the phytoplankton were Bacillariophyceae and zooplankton were Copepoda.

  17. The onset of the 'Ordovician Plankton Revolution' in the late Cambrian

    DEFF Research Database (Denmark)

    Servais, Thomas; Perrier, Vincent; Danelian, Taniel

    2016-01-01

    Positive Carbon Isotope Excursion δ13Ccarb (SPICE) event in the late Cambrian (Paibian Stage, Furongian Series) has been related to a major increase in atmospheric O2 (from 10-18% to some 20 - 29%) and to increased oceanic nutrient availability. Here we analyze the diversification of the planktonic groups...... during the late Cambrian and Early Ordovician, in particular in relation to the SPICE event. Our analyses include the changing diversities of the phytoplankton (acritarchs), diverse groups of zooplankton (e.g., radiolarians, graptolites, chitinozoans) and the switch to a planktonic mode of life of fossil...... of the different planktonic organisms can be related directly to the SPICE event. However, a long term (10-20millionyears) oxygenation pulse related to the SPICE event might have fuelled the explosion of phytoplankton diversity observed in the latest Cambrian-Early Ordovician that led to completely modified...

  18. Size distribution of planktonic autotrophy and microheterotrophy in DeGray Reservoir, Arkansas

    International Nuclear Information System (INIS)

    Kimmel, B.L.; Groeger, A.W.

    1983-01-01

    Naturally occurring assemblages of phytoplankton and bacterioplankton were radiolabelled with sodium 14 C-bicarbonate and sodium 3 H-acetate and size fractionated to determine the size structure of planktonic autotrophy and microheterotrophy in DeGray Reservoir, an oligotrophic impoundment of the Caddo River in south-central Arkansas. Size distributions of autotrophy and microheterotrophy were remarkably uniform seasonally, vertically within the water column, and along the longitudinal axis of the reservoir despite significant changes in environmental conditions. Planktonic autotrophy was dominated by small algal cells with usually >50% of the photosynthetic carbon uptake accounted for by organisms 75% of the planktonic microheterotrophy. Longitudinal patterns in autotrophic and microheterotrophic activities associated with >3-μm and >1-μm size fractions, respectively, suggest an uplake to downlake shift from riverine to lacustrine environmental influences within the reservoir. 83 references, 7 figures

  19. Global marine plankton functional type biomass distributions: Phaeocystis spp.

    Directory of Open Access Journals (Sweden)

    C. Widdicombe

    2012-09-01

    Full Text Available The planktonic haptophyte Phaeocystis has been suggested to play a fundamental role in the global biogeochemical cycling of carbon and sulphur, but little is known about its global biomass distribution. We have collected global microscopy data of the genus Phaeocystis and converted abundance data to carbon biomass using species-specific carbon conversion factors. Microscopic counts of single-celled and colonial Phaeocystis were obtained both through the mining of online databases and by accepting direct submissions (both published and unpublished from Phaeocystis specialists. We recorded abundance data from a total of 1595 depth-resolved stations sampled between 1955–2009. The quality-controlled dataset includes 5057 counts of individual Phaeocystis cells resolved to species level and information regarding life-stages from 3526 samples. 83% of stations were located in the Northern Hemisphere while 17% were located in the Southern Hemisphere. Most data were located in the latitude range of 50–70° N. While the seasonal distribution of Northern Hemisphere data was well-balanced, Southern Hemisphere data was biased towards summer months. Mean species- and form-specific cell diameters were determined from previously published studies. Cell diameters were used to calculate the cellular biovolume of Phaeocystis cells, assuming spherical geometry. Cell biomass was calculated using a carbon conversion factor for prymnesiophytes. For colonies, the number of cells per colony was derived from the colony volume. Cell numbers were then converted to carbon concentrations. An estimation of colonial mucus carbon was included a posteriori, assuming a mean colony size for each species. Carbon content per cell ranged from 9 pg C cell−1 (single-celled Phaeocystis antarctica to 29 pg C cell−1 (colonial Phaeocystis globosa. Non-zero Phaeocystis cell biomasses (without mucus carbon range from 2.9 × 10−5 to 5.4 × 103 μg C l−1, with a mean of 45.7 μg C

  20. Inorganic mercury (Hg2+ uptake by different plankton fractions of Andean Patagonian lakes (Argentina

    Directory of Open Access Journals (Sweden)

    Diéguez M.C.

    2014-07-01

    Full Text Available The species composition and the size structure of natural planktonic food webs may provide essential information to understand the fate of mercury and, in particular, the bioaccumulation pattern of Hg2+ in the water column of lake ecosystems. Heterotrophic and autotrophic picoplankton and phytoplankton are the most important entry points for Hg in aquatic ecosystems since they concentrate Hg2+ and MeHg from ambient water, making them available to planktonic consumers at higher trophic levels of lake food webs. In this investigation we studied the uptake of 197Hg2+ in natural plankton assemblages from four Andean lakes (Nahuel Huapi National Park, Patagonia, Argentina, comprised in the size fractions 0.2-2.7 μm (picoplankton, 0.2-20 μm (pico and nanoplankton and 20-50 μm (microplankton through experiments using Hg2+ labeled with 197Hg2+. The experimental results showed that the uptake of Hg2+ was highest in the smallest plankton fractions (0.2-2.7 μm and 0.2-20 μm compared to the larger fraction comprising microplankton (20-50 um. This pattern was consistent in all lakes, reinforcing the idea that among pelagic organisms, heterotrophic and autotrophic bacteria with the contribution of nanoflagellates and dinoflagellates constitute the main entry point of Hg2+ to the pelagic food web. Moreover, a significant direct relationship was found between the Hg2+ uptake and surface index of the planktonic fractions (SIf. Thus, the smaller planktonic fractions which bore the higher SI were the major contributors to the Hg2+ passing from the abiotic to the biotic pelagic compartments of these Andean lakes.

  1. Progress Towards a Global Understanding of Plankton Dynamics: The Global Alliance of CPR Surveys (GACS)

    Science.gov (United States)

    Batten, S.; Richardson, A.; Melrose, C.; Muxagata, E.; Hosie, G.; Verheye, H.; Hall, J.; Edwards, M.; Koubbi, P.; Abu-Alhaija, R.; Chiba, S.; Wilson, W.; Nagappa, R.; Takahashi, K.

    2016-02-01

    The Continuous Plankton Recorder (CPR) was first used in 1931 to routinely sample plankton and its continued deployment now sustains the longest-running, and spatially most extensive marine biological sampling programme in the world. Towed behind, for the most part commercial, ships it collects plankton samples from the surface waters that are subsequently analysed to provide taxonomically-resolved abundance data on a broad range of planktonic organisms from the size of coccolithophores to euphausiids. Plankton appear to integrate changes in the physical environment and by underpinning most marine food-webs, pass on this variability to higher trophic levels which have societal value. CPRs are deployed increasingly around the globe in discrete regional surveys that until recently interacted in an informal way. In 2011 the Global Alliance of CPR Surveys (GACS) was launched to bring these surveys together to collaborate more productively and address issues such as: methodological standardization, data integration, capacity building, and data analysis. Early products include a combined global database and regularly-released global marine ecological status reports. There are, of course, limitations to the exploitation of CPR data as well as the current geographic coverage. A current focus of GACS is integration of the data with models to meaningfully extrapolate across time and space. In this way the output could be used to provide more robust synoptic representations of key plankton variables. Recent years have also seen the CPR used as a platform in itself with the inclusion of additional sensors and water samplers that can sample the microplankton. The archive of samples has already been used for some molecular investigations and curation of samples is maintained for future studies. Thus the CPR is a key element of any regional to global ocean observing system of biodiversity.

  2. The influence of nitrogen inputs on biomass and trophic structure of ocean plankton: a study using biomass and stable isotope size-spectra

    KAUST Repository

    Mompeá n, Carmen; Bode, Antonio; Latasa, Mikel; Ferná ndez-Castro, Bieito; Mouriñ o-Carballido, Beatriz; Irigoien, Xabier

    2016-01-01

    Large scale patterns in planktonic food web structure were studied by applying continuous size-scaled models of biomass and δ15N to plankton samples, collected at 145 stations during the Malaspina-2010 Expedition across three ocean basins

  3. Smoothing a Piecewise-Smooth: An Example from Plankton Population Dynamics

    DEFF Research Database (Denmark)

    Piltz, Sofia Helena

    2016-01-01

    In this work we discuss a piecewise-smooth dynamical system inspired by plankton observations and constructed for one predator switching its diet between two different types of prey. We then discuss two smooth formulations of the piecewise-smooth model obtained by using a hyperbolic tangent funct...... function and adding a dimension to the system. We compare model behaviour of the three systems and show an example case where the steepness of the switch is determined from a comparison with data on freshwater plankton....

  4. Study on kinetics of glucose uptake by some species of plankton

    Science.gov (United States)

    Li, Wenquan; Wang, Xian; Zhang, Yaohua

    1993-03-01

    The rates of glucose uptake by some species of plankton were determined by3H-glucose tracer method. Experimental results indicated that the observed glucose uptake at natural seawater concentrations by Platymonas subcordiformis and Brachionus plicatilis was principally a metabolic process fitted with the Michaelis-Menten equation in the range of adaptive temperatures. Heterotrophic uptake by Platymonas subcordiformis was mainly dependent on diffusion at high glucose levels. The uptake by Brachionus plicatilis showed active transport even at high glucose levels, indicating its high heterotrophic activity. The uptake rate by Artemia salina was lower, and its V m/K ratio was lower than those of the other two species of plankton.

  5. Plankton biomass in secondary ponds treating piggery waste

    Directory of Open Access Journals (Sweden)

    Lígia Barthel

    2008-12-01

    Full Text Available This study aimed at analyzing the plankton biomass found in a piggery waste treatment system, composed of a high rate algal pond (HRAP, two maturation ponds (MP1, MP2 (System A and a water hyacinth pond (WHP (System B. The ponds were disposed in series and the study was performed for 32 weeks. The physicochemical variables monitored were: pH, temperature, dissolved oxygen, soluble chemical oxygen demand, nitrogen compounds and total phosphorus. The plankton biomass was identified at genus level and the ecology index was calculated so as to describe its development in the ponds. Results showed lower specific richness, which was associated to the mono-specific Chlorella sp population. The protozoa density was conversely proportional to the green algae density. The higher species diversity occurred in the WHP and MP2. The green algae presented high relative density (>97 %. The Jaccard index reached 100% if Chlorella sp and sometimes diatoms were found in the system's inlet and outlet. The productivity of algal biomass was lower than 10 gTSS/m²/d in the maturation ponds, which was maintained in the HRAP. The green algae coefficient of variation (CV varied from 0 to 1.5 in the HRAP and WHP, but was constant at 0.9 to the 10th week in MP1 and around 0.5 during all the experimental period for MP2. For the chlorophyll a, this coefficient varied in all the ponds.Este trabalho teve como objetivo estudar a biomassa do plâncton encontrado em um sistema de tratamento de dejetos suínos, formado por uma série de lagoas. Foram monitoradas 1 lagoa de alta taxa (LAT, 2 lagoas de maturação (LM1, LM2 (sistema A e 1 lagoa de aguapés (LAG (sistema B, durante 32 semanas, por meio de variáveis físico-químicas tais como pH, temperatura, oxigênio dissolvido, demanda química de oxigênio, compostos nitrogenados e fósforo total. Igualmente, foram feitas identificações da biomassa planctônica, a nível de gênero, e calculados índices ecológicos que

  6. Bacteriophage-antibiotic synergism to control planktonic and biofilm ...

    African Journals Online (AJOL)

    Amina Amal Mahmoud Nouraldin

    2015-07-11

    Jul 11, 2015 ... mote resistance to antimicrobial agents, and its occurrence during the infectious ... Biofilm is a structured community of bacterial cells adher- ent to an inert or ..... biofilms with bacteriophages and chlorine. Biotechnol Bioeng.

  7. Disorders of carbohydrate metabolism in clinical practice

    Directory of Open Access Journals (Sweden)

    V.I. Pankiv

    2017-02-01

    Full Text Available Considering the prevalence of diabetes mellitus (DM, the possibility of early and rapid progress of complications, a large number of undiagnosed cases and disappointing forecasts of the World Health Organization on the prospects of DM spreading in the world, timely and accurate diagnosis of carbohydrate metabolism disorders is important. The criteria for the diagnosis of carbohydrate metabolism and DM are shown in the article. The article includes a new consensus on the staging of type 1 DM and a discussion of a proposed unifying diabetes classification scheme that focuses on β-cell dysfunction and disease stage as indicated by glucose status. Modern recommendations 2017 of the American Diabetes Association are shown in relation to the criteria of diagnostics of impaired fasting glucose, impaired glucose tolerance and diabetes mellitus. The value of insulin resistance and functional state of pancreatic β-cells is underlined in determination of type 2 DM duration. A plan of type 2 DM management is brought.

  8. Solubility of carbohydrates in heavy water.

    Science.gov (United States)

    Cardoso, Marcus V C; Carvalho, Larissa V C; Sabadini, Edvaldo

    2012-05-15

    The solubility of several mono-(glucose and xylose), di-(sucrose and maltose), tri-(raffinose) and cyclic (α-cyclodextrin) saccharides in H(2)O and in D(2)O were measured over a range of temperatures. The solution enthalpies for the different carbohydrates in the two solvents were determined using the vant' Hoff equation and the values in D(2)O are presented here for the first time. Our findings indicate that the replacement of H(2)O by D(2)O remarkably decreases the solubilities of the less soluble carbohydrates, such as maltose, raffinose and α-cyclodextrin. On the other hand, the more soluble saccharides, glucose, xylose, and sucrose, are practically insensitive to the H/D replacement in water. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Role of carbohydrate metabolism in grass tetany

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.K.; Madsen, F.C.; Lentz, D.E.; Hansard, S.L.

    1977-01-01

    Clinical hypomagnesemia is confined primarily to beef cattle in the United States but also occurs in dairy cattle in other countries, probably due to different management practices. During periods when grass tetany is likely, early vegetative temperate zone grasses are usually low in total readily available carbohydrates and magnesium but high in potassium and nitrogen. The tetany syndrome may include hypoglycemia and ketosis, suggesting an imbalance in intermediary energy metabolism. Many enzyme systems critical to cellular metabolism, including those which hydrolyze and transfer phosphate groups, are activated by Mg. Thus, by inference, Mg is required for normal glucose utilization, fat, protein, nucleic acid and coenzyme synthesis, muscle contraction, methyl group transfer, and sulfate, acetate, and formate activation. Numerous clinical and experimental studies suggest an intimate relationship between metabolism of Mg and that of carbohydrate, glucagon, and insulin. The objective is to review this literature and suggest ways in which these relationships might contribute to a chain of events leading to grass tetany.

  10. Carbohydrates and the human gut microbiota.

    Science.gov (United States)

    Chassard, Christophe; Lacroix, Christophe

    2013-07-01

    Due to its scale and its important role in maintaining health, the gut microbiota can be considered as a 'new organ' inside the human body. Many complex carbohydrates are degraded and fermented by the human gut microbiota in the large intestine to both yield basic energy salvage and impact gut health through produced metabolites. This review will focus on the gut microbes and microbial mechanisms responsible for polysaccharides degradation and fermentation in the large intestine. Gut microbes and bacterial metabolites impact the host at many levels, including modulation of inflammation, and glucose and lipid metabolisms. A complex relationship occurs in the intestine between the human gut microbiota, diet and the host. Research on carbohydrates and gut microbiota composition and functionality is fast developing and will open opportunities for prevention and treatment of obesity, diabetes and other related metabolic disorders through manipulation of the gut ecosystem.

  11. Carbocyclic Carbohydrate Mimics as Potential Glycosidase Inhibitors

    DEFF Research Database (Denmark)

    Fanefjord, Mette; Lundt, Inge

    It has been proven that aminocyclopentanols having the aminogroup adjacent to a carbon sidechain could be potential anomer-selective glycosidase inhibitors [1]. A successful pathway for synthesising mimics to L-carbohydrates 2, by introducing nitrogen to the C6 position in compound 1, has been...... developed in our group. A similar strategy has been used for synthesising mimics of D-carbohydrates. The α,β-unsaturated lactone 3 was cyclised to compound 4 which was further transformed into 5. The nitrogen functionality in compound 7 is introduced by an Overman rearrangement of 6 and the hydroxyl...... functionalities was introduced by either epoxidation or dihydroxylation of 7. Finally, reduction of the lactone ring led to the sugar mimics 8. The synthesis of several isomers of 8 will be presented. [1] a) Kleban, M. ; Hilgers, P. ; Greul, J.N. ; Kugler, R.D. ; Li, J. ; Picasso, S. ; Vogel, P. ; Jäger, V. Chem...

  12. Analysis and validation of carbohydrate three-dimensional structures

    International Nuclear Information System (INIS)

    Lütteke, Thomas

    2009-01-01

    The article summarizes the information that is gained from and the errors that are found in carbohydrate structures in the Protein Data Bank. Validation tools that can locate these errors are described. Knowledge of the three-dimensional structures of the carbohydrate molecules is indispensable for a full understanding of the molecular processes in which carbohydrates are involved, such as protein glycosylation or protein–carbohydrate interactions. The Protein Data Bank (PDB) is a valuable resource for three-dimensional structural information on glycoproteins and protein–carbohydrate complexes. Unfortunately, many carbohydrate moieties in the PDB contain inconsistencies or errors. This article gives an overview of the information that can be obtained from individual PDB entries and from statistical analyses of sets of three-dimensional structures, of typical problems that arise during the analysis of carbohydrate three-dimensional structures and of the validation tools that are currently available to scientists to evaluate the quality of these structures

  13. Community genomics among stratified microbial assemblages in the ocean's interior

    DEFF Research Database (Denmark)

    DeLong, Edward F; Preston, Christina M; Mincer, Tracy

    2006-01-01

    Microbial life predominates in the ocean, yet little is known about its genomic variability, especially along the depth continuum. We report here genomic analyses of planktonic microbial communities in the North Pacific Subtropical Gyre, from the ocean's surface to near-sea floor depths. Sequence......, and host-viral interactions. Comparative genomic analyses of stratified microbial communities have the potential to provide significant insight into higher-order community organization and dynamics....

  14. A rapid stereoselective synthesis of fluorinated carbohydrates

    International Nuclear Information System (INIS)

    Adam, M.J.; Neeser, J-R.; Hall, L.D.; Pate, B.D.

    1983-01-01

    Acetyl hypofluorite has been added to six unsaturated carbohydrates which contain the vinyl ether moiety. All reactions were rapid (less than 5 min.) at -78 degrees C and gave, with one exception, high yields of isomerically pure products. The hypofluorite was shown to add exclusively in a cis mode and with a strong preference for a particular 'face' of the double bond. As well as the syntheses, NMR data and preferred conformations for the fluorinated products are also discussed

  15. Hearing Loss, Dizziness, and Carbohydrate Metabolism

    OpenAIRE

    Albernaz, Pedro L. Mangabeira

    2015-01-01

    Abstract Introduction Metabolic activity of the inner ear is very intense, and makes it sensitive to changes in the body homeostasis. This study involves a group of patients with inner ear disorders related to carbohydrate metabolism disturbances, including hearing loss, tinnitus, dizziness, and episodes of vertigo. Objectives To describe the symptoms of metabolic inner ear disorders and the examinations required to establish diagnoses. These symptoms are often the first to allow for an e...

  16. Impact of carbohydrates on weight regain.

    Science.gov (United States)

    Bosy-Westphal, Anja; Müller, Manfred J

    2015-07-01

    Research on obesity treatment has shifted its focus from weight loss to weight-loss maintenance strategies. The conventional approach of a low-fat diet is challenged by insights from glycemic effects of carbohydrates on body weight regulation. Metabolic and endocrine adaptations to weight loss that contribute to weight regain involve reduced energy expenditure, increased insulin sensitivity, and enhanced orexigenic signals. This review summarizes the impact of carbohydrates on energetic efficiency, partitioning of weight regain as fat and lean mass, and appetite control. Both the amount and frequency of postprandial glycemia add to body weight regulation after weight loss and strengthen the concept of glycemic index and glycemic load. In addition, dietary fiber and slowly or poorly absorbable functional sugars modify gastrointestinal peptides involved in appetite and metabolic regulation and exert prebiotic effects. Current evidence suggests that a low-glycemic load diet with a preference for low-glycemic index foods and integration of slowly digestible, poorly absorbable carbohydrates may improve weight-loss maintenance. Future studies should investigate the health benefits of low glycemic functional sweeteners (e.g., isomaltulose and tagatose).

  17. Hearing Loss, Dizziness, and Carbohydrate Metabolism.

    Science.gov (United States)

    Albernaz, Pedro L Mangabeira

    2016-07-01

    Metabolic activity of the inner ear is very intense, and makes it sensitive to changes in the body homeostasis. This study involves a group of patients with inner ear disorders related to carbohydrate metabolism disturbances, including hearing loss, tinnitus, dizziness, and episodes of vertigo. To describe the symptoms of metabolic inner ear disorders and the examinations required to establish diagnoses. These symptoms are often the first to allow for an early diagnosis of metabolic disorders and diabetes. Retrospective study of 376 patients with inner ear symptoms suggestive of disturbances of carbohydrate metabolism. The authors present patientś clinical symptoms and clinical evaluations, with emphasis on the glucose and insulin essays. Authors based their conclusions on otolaryngological findings, diagnostic procedures and treatment principles. They found that auditory and vestibular symptoms usually occur prior to other manifestations of metabolic changes, leading to an early diagnosis of hyperinsulinemia, intestinal sugar malabsorption or diabetes. Previously undiagnosed diabetes mellitus type II was found in 39 patients. The identification of carbohydrate metabolism disturbances is important not only to minimize the patients' clinical symptoms, but also to help maintain their general health.

  18. Hearing Loss, Dizziness, and Carbohydrate Metabolism

    Directory of Open Access Journals (Sweden)

    Albernaz, Pedro L. Mangabeira

    2015-07-01

    Full Text Available Introduction Metabolic activity of the inner ear is very intense, and makes it sensitive to changes in the body homeostasis. This study involves a group of patients with inner ear disorders related to carbohydrate metabolism disturbances, including hearing loss, tinnitus, dizziness, and episodes of vertigo. Objectives To describe the symptoms of metabolic inner ear disorders and the examinations required to establish diagnoses. These symptoms are often the first to allow for an early diagnosis of metabolic disorders and diabetes. Methods Retrospective study of 376 patients with inner ear symptoms suggestive of disturbances of carbohydrate metabolism. The authors present patientś clinical symptoms and clinical evaluations, with emphasis on the glucose and insulin essays. Results Authors based their conclusions on otolaryngological findings, diagnostic procedures and treatment principles. They found that auditory and vestibular symptoms usually occur prior to other manifestations of metabolic changes, leading to an early diagnosis of hyperinsulinemia, intestinal sugar malabsorption or diabetes. Previously undiagnosed diabetes mellitus type II was found in 39 patients. Conclusions The identification of carbohydrate metabolism disturbances is important not only to minimize the patients' clinical symptoms, but also to help maintain their general health.

  19. Acclimatory responses of the Daphnia pulex proteome to environmental changes. I. Chronic exposure to hypoxia affects the oxygen transport system and carbohydrate metabolism

    Directory of Open Access Journals (Sweden)

    Madlung Johannes

    2009-04-01

    Full Text Available Abstract Background Freshwater planktonic crustaceans of the genus Daphnia show a remarkable plasticity to cope with environmental changes in oxygen concentration and temperature. One of the key proteins of adaptive gene control in Daphnia pulex under hypoxia is hemoglobin (Hb, which increases in hemolymph concentration by an order of magnitude and shows an enhanced oxygen affinity due to changes in subunit composition. To explore the full spectrum of adaptive protein expression in response to low-oxygen conditions, two-dimensional gel electrophoresis and mass spectrometry were used to analyze the proteome composition of animals acclimated to normoxia (oxygen partial pressure [Po2]: 20 kPa and hypoxia (Po2: 3 kPa, respectively. Results The comparative proteome analysis showed an up-regulation of more than 50 protein spots under hypoxia. Identification of a major share of these spots revealed acclimatory changes for Hb, glycolytic enzymes (enolase, and enzymes involved in the degradation of storage and structural carbohydrates (e.g. cellubiohydrolase. Proteolytic enzymes remained constitutively expressed on a high level. Conclusion Acclimatory adjustments of the D. pulex proteome to hypoxia included a strong induction of Hb and carbohydrate-degrading enzymes. The scenario of adaptive protein expression under environmental hypoxia can be interpreted as a process to improve oxygen transport and carbohydrate provision for the maintenance of ATP production, even during short episodes of tissue hypoxia requiring support from anaerobic metabolism.

  20. Hydrology, plankton, and corals of the Maracajaú reefs (Northeastern Brazil: an ecosystem under severe thermal stress

    Directory of Open Access Journals (Sweden)

    Elga Miranda Mayal

    2009-06-01

    Full Text Available This study provides baseline information on the hydrological conditions and on the coral and plankton communities at the Maracajaú reef ecosystem (Northeastern Brazil. Studies were performed from February to June 2000, covering the transition from dry to rainy season. In this area, there is an offshore coral reef formation, where corals were observed in loco; the water samples were collected to obtain the hydrological and plankton data. Six scleractinian species were identified. Stable isotope analysis on the carbonate fraction of Favia gravida fragments showed that these corals were under severe thermal stress. Chlorophyll-a varied from 1.1 to 9.3 mg m-3, with higher values during the rainy season. Average zooplankton wet weight biomass were 117.0 (microzooplankton and 15.7 mg m -3(mesozooplankton. A total of 136 Phytoplankton and 61 zooplankton taxa were identified. Seasonal forcing determined the phyto-micro-and mesozooplankton community structure, rather than the coastal-offshore gradient.Esta pesquisa apresenta informações básicas sobre as condições hidrológicas e sobre as comunidades de corais e do plâncton no ecossistema recifal de Maracajaú (Nordeste do Brasil. Estudos foram realizados de fevereiro a junho de 2000, cobrindo o período de transição das estações seca a chuvosa. Nesta area existe uma formação de recife de coral afastada da costa, onde os corais foram observados in loco e amostras de água foram coletadas para a obtenção de dados hidrológicos e planctônicos. Foram identificadas seis espécies de escleractíneos. Análises com isótopos estáveis em fragmentos de carbonato de Favia gravida mostraram que este coral está sob estresse termal severo. As concentrações de clorofila-a variaram de 1,1 mg m-3 a 9,3 mg m-3, com maiores valores durante o período chuvoso. A biomassa média em peso úmido do zooplâncton foi de 117,0 mg m-3 para o microzooplâncton e de 15,7 mg m-3 para o mesozooplâncton. Foram

  1. Algal communities associated with aquatic macrophytes in some ...

    African Journals Online (AJOL)

    This study describes the algal communities of six ponds colonised by aquatic macrophytes in Nyanza Province, Kenya. Plankton samples were collected from the water column and epiphytic samples from macrophytes such as Azolla, Pistia, Nymphaea, Ipomoea and Ludwigia. Pond pH, temperature, conductivity, ...

  2. Large Plankton Enhance Heterotrophy Under Experimental Warming in a Temperate Coastal Ecosystem

    KAUST Repository

    Huete-Stauffer, Tamara Megan; Arandia-Gorostidi, Nestor; Gonzá lez-Bení tez, Natalia; Dí az-Pé rez, Laura; Calvo-Dí az, Alejandra; Moran, Xose Anxelu G.

    2017-01-01

    in February, April, August and October 2013 in coastal NE Atlantic waters, we monitored microbial plankton stocks and daily rates of primary production, bacterial heterotrophic production and respiration at in situ temperature and at 2 and 4°C over ambient

  3. Fate and effects of the insecticide chlorpyrifos in outdoor plankton-dominated microcosms in Thailand.

    NARCIS (Netherlands)

    Daam, M.A.; Crum, S.J.H.; Brink, van den P.J.; Nogueira, A.J.A.

    2008-01-01

    The fate and effects of the insecticide chlorpyrifos were studied in plankton-dominated, freshwater microcosms in Thailand. Disappearance rates of chlorpyrifos from the water column in the present study were similar to those in temperate regions. Insecticide accumulation in the sediment was

  4. Pre-monsoon living planktonic foraminifera from the Southeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.; Naidu, P.D.; Muralinath, A.S.

    LOGICAL SoCIETY OF INDIA Vol. 36, Dec. 1990, pp. 654 to 660 Pre-Monsoon Living Planktonic Foraminifera from the Southeastern Arabian Sea M. V. S. GUPTHA.. P. DIVAKAR NAlDU AND A. S. MURALINATH Nalional Institute of Oceanography, Dona Paula, Goa 403004...

  5. Drivers of Plankton Patch Formation, Persistence and Decline in East Sound, Orcas Island, Washington

    Science.gov (United States)

    2012-09-30

    Population dynamics of the marine planktonic ciliate Strombidinopsis multiauris: its potential to control phytoplankton blooms . Aquat. Microb. Ecol., 20...radii with patch exploitation in the coastal ocean. 5th International Zooplankton Production Symposium. Pucón, Chile Menden-Deuer S & Harvey* EL

  6. Persistent organic pollutants in Mediterranean seawater and processes affecting their accumulation in plankton.

    Science.gov (United States)

    Berrojalbiz, Naiara; Dachs, Jordi; Del Vento, Sabino; Ojeda, María José; Valle, María Carmen; Castro-Jiménez, Javier; Mariani, Giulio; Wollgast, Jan; Hanke, Georg

    2011-05-15

    The Mediterranean and Black Seas are unique marine environments subject to important anthropogenic pressures due to riverine and atmospheric inputs of organic pollutants. Here, we report the results obtained during two east-west sampling cruises in June 2006 and May 2007 from Barcelona to Istanbul and Alexandria, respectively, where water and plankton samples were collected simultaneously. Both matrixes were analyzed for hexaclorochyclohexanes (HCHs), hexachlorobenzene (HCB), and 41 polychlorinated biphenyl (PCB) congeners. The comparison of the measured HCB and HCHs concentrations with previously reported dissolved phase concentrations suggests a temporal decline in their concentrations since the 1990s. On the contrary, PCB seawater concentrations did not exhibit such a decline, but show a significant spatial variability in dissolved concentrations with lower levels in the open Western and South Eastern Mediterranean, and higher concentrations in the Black, Marmara, and Aegean Seas and Sicilian Strait. PCB and OCPs (organochlorine pesticides) concentrations in plankton were higher at lower plankton biomass, but the intensity of this trend depended on the compound hydrophobicity (K(OW)). For the more persistent PCBs and HCB, the observed dependence of POP concentrations in plankton versus biomass can be explained by interactions between air-water exchange, particle settling, and/or bioaccumulation processes, whereas degradation processes occurring in the photic zone drive the trends shown by the more labile HCHs. The results presented here provide clear evidence of the important physical and biogeochemical controls on POP occurrence in the marine environment.

  7. Differential Protein Expression in Streptococcus uberis under Planktonic and Biofilm Growth Conditions ▿ †

    Science.gov (United States)

    Crowley, R. C.; Leigh, J. A.; Ward, P. N.; Lappin-Scott, H. M.; Bowler, L. D.

    2011-01-01

    The bovine pathogen Streptococcus uberis was assessed for biofilm growth. The transition from planktonic to biofilm growth in strain 0140J correlated with an upregulation of several gene products that have been shown to be important for pathogenesis, including a glutamine ABC transporter (SUB1152) and a lactoferrin binding protein (gene lbp; protein SUB0145). PMID:21075893

  8. Arsenic in water, plankton and sediments off Goa coast and adjacent regions

    Digital Repository Service at National Institute of Oceanography (India)

    Fondekar, S.P.; Shirodkar, P.V.; Joseph, T.

    as soluble inorganic arsenic and the rest as organic bound arsenic. Plankton and sediments also showed marked accumulation of this element, the average being 2.2 and 8.8 mu g/g respectively. Nearshore sediments showed higher values of arsenic indicating...

  9. Studies on planktonic decapoda and stomatopoda (Crustacea) from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Paulinose, V.T.; Goswami, S.C.; Nair, V.R.

    and longitudes 66 degrees 00' and 78 degrees 00'E and depths ranging from 25 to 500 m. Only 40 samples out of 93, contained planktonic decapods and stomatopods. Maximum number of larvae (1501/100 m3) was obtained from Station 228 (Ga. Cr. 13), a very shallow...

  10. Accuracy in correlation and ecological aspects of the planktonic foraminiferal zonation of the mediterranean pliocene

    NARCIS (Netherlands)

    Spaak, P.

    1982-01-01

    Pliocene planktonic foraminiferal assoclatlOns from Cretan, Sicilian and Calabrian sections have been studied qualitatively and quantitatively in order to evaluate the Pliocene biozonation for the Mediterranean. Six zones can be clearly distinguished and in the middle part of the Pliocene a

  11. Planktonic primary production evaluation by means of the 14C method with liquid scintillation counting

    International Nuclear Information System (INIS)

    Frangopol, T.P.; Bologa, S.A.

    1979-05-01

    Preliminary results on the planktonic primary production obtained for the first time with the 14 C method off the Romanian Black Sea coast (1977, 1978) and in the Sinoe, Mamaia and Bicaz lakes (1978) are presented, along with a review of this method with special reference to liquid scintillation counting. 140 Refs. (author)

  12. Estimates of zooplankton abundance and size distribution with the Optical Plankton Counter (OPC)

    DEFF Research Database (Denmark)

    Wieland, Kai; Petersen, D.; Schnack, D.

    1997-01-01

    The capability of the Optical Plankton Count er (OPC) to examine the abundance and size distribution of zooplankton was tested in Storfjorden, Norway, in June 1993. Selected material obtained from net sampling was measured with a laboratory version of the OPC and compared with microscope analysis...

  13. Effects of Photoactivated Titanium Dioxide Nanopowders and Coating on Planktonic and Biofilm Growth of Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Polo, Andrea; Diamanti, Maria Vittoria; Bjarnsholt, Thomas

    2011-01-01

    eradication of P. aeruginosa planktonic cells (initial concentration 10(8) cells/ml) in 24 h compared to a 3-log reduction caused by UV-A light alone. In contrast, neither the photocatalytic treatment with TiO(2) film nor that with TiO(2) nanopowder had any effect on P. aeruginosa biofilms at all...

  14. Planktonic Euryarchaeota are a significant source of archaeal tetraether lipids in the ocean.

    Science.gov (United States)

    Lincoln, Sara A; Wai, Brenner; Eppley, John M; Church, Matthew J; Summons, Roger E; DeLong, Edward F

    2014-07-08

    Archaea are ubiquitous in marine plankton, and fossil forms of archaeal tetraether membrane lipids in sedimentary rocks document their participation in marine biogeochemical cycles for >100 million years. Ribosomal RNA surveys have identified four major clades of planktonic archaea but, to date, tetraether lipids have been characterized in only one, the Marine Group I Thaumarchaeota. The membrane lipid composition of the other planktonic archaeal groups--all uncultured Euryarchaeota--is currently unknown. Using integrated nucleic acid and lipid analyses, we found that Marine Group II Euryarchaeota (MG-II) contributed significantly to the tetraether lipid pool in the North Pacific Subtropical Gyre at shallow to intermediate depths. Our data strongly suggested that MG-II also synthesize crenarchaeol, a tetraether lipid previously considered to be a unique biomarker for Thaumarchaeota. Metagenomic datasets spanning 5 y indicated that depth stratification of planktonic archaeal groups was a stable feature in the North Pacific Subtropical Gyre. The consistent prevalence of MG-II at depths where the bulk of exported organic matter originates, together with their ubiquitous distribution over diverse oceanic provinces, suggests that this clade is a significant source of tetraether lipids to marine sediments. Our results are relevant to archaeal lipid biomarker applications in the modern oceans and the interpretation of these compounds in the geologic record.

  15. Estuarine water quality and plankton community responses in the Pensacola Bay Estuary

    Science.gov (United States)

    Phytoplankton serve a centrally important role in estuaries forming the base of the food web. Thus factors that affect phytoplankton production and species composition cascades to higher trophic levels, ultimately affecting secondary production. Given their sensitivity to myriad ...

  16. Cyclone phyan-induced plankton community succession in the coastal waters off Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Gauns, M.; Kurian, S.; Shenoy, D.M.; Naik, H.; Naqvi, S.W.A.

    primary production, particulate organic carbon concentration and bacterial production roughly twofold. Likewise, studies carried out by Shi and Wang3 from the Gulf of Mexico, a region hit by hurricane Katrina in August 2005, also showed a prominent... winter storm in the coastal and inner shelf waters of the northern Gulf of Mexico. Cont. Shelf Res., 1988, 8, 167–178. RESEARCH COMMUNICATIONS CURRENT SCIENCE, VOL. 111, NO. 6, 25 SEPTEMBER 2016 1097 *For correspondence. (e-mail: aravind...

  17. Antimicrobial Resistance Profile of Planktonic and Biofilm Cells of Staphylococcus aureus and Coagulase-Negative Staphylococci

    Directory of Open Access Journals (Sweden)

    Adilson de Oliveira

    2016-09-01

    Full Text Available The objective of the present study was to determine the antimicrobial resistance profile of planktonic and biofilm cells of Staphylococcus aureus and coagulase-negative staphylococci (CoNS. Two hundred Staphylococcus spp. strains were studied, including 50 S. aureus and 150 CoNS strains (50 S. epidermidis, 20 S. haemolyticus, 20 S. warneri, 20 S. hominis, 20 S. lugdunensis, and 20 S. saprophyticus. Biofilm formation was investigated by adherence to polystyrene plates. Positive strains were submitted to the broth microdilution method to determine the minimum inhibitory concentration (MIC for planktonic and biofilm cells and the minimal bactericidal concentration for biofilm cells (MBCB. Forty-nine Staphylococcus spp. strains (14 S. aureus, 13 S. epidermidis, 13 S. saprophyticus, 3 S. haemolyticus, 1 S. hominis, 3 S. warneri, and 2 S. lugdunensis were biofilm producers. These isolates were evaluated regarding their resistance profile. Determination of planktonic cell MIC identified three (21.4% S. aureus strains that were resistant to oxacillin and six (42.8% that were resistant to erythromycin. Among the CoNS, 31 (88.6% strains were resistant to oxacillin, 14 (40% to erythromycin, 18 (51.4% to gentamicin, and 8 (22.8% to sulfamethoxazole/trimethoprim. None of the planktonic isolates were resistant to vancomycin or linezolid. MICs were 2-, 4-, 8-, and up to 16-fold higher for biofilm cells than for planktonic cells. This observation was more common for vancomycin and erythromycin. The MBCB ranged from 8 to >256 µg/mL for oxacillin, 128 to >128 µg/mL for vancomycin, 256 to >256 µg/mL for erythromycin and gentamicin, >64 µg/mL for linezolid, and 32/608 to >32/608 µg/mL for sulfamethoxazole/trimethoprim. The results showed considerably higher MICs for S. aureus and CoNS biofilm cells compared to planktonic cells. Analysis of MBCM confirmed that even high concentrations of vancomycin were unable to eliminate the biofilms of S. aureus and Co

  18. Discovery and design of carbohydrate-based therapeutics.

    Science.gov (United States)

    Cipolla, Laura; Araújo, Ana C; Bini, Davide; Gabrielli, Luca; Russo, Laura; Shaikh, Nasrin

    2010-08-01

    Till now, the importance of carbohydrates has been underscored, if compared with the two other major classes of biopolymers such as oligonucleotides and proteins. Recent advances in glycobiology and glycochemistry have imparted a strong interest in the study of this enormous family of biomolecules. Carbohydrates have been shown to be implicated in recognition processes, such as cell-cell adhesion, cell-extracellular matrix adhesion and cell-intruder recognition phenomena. In addition, carbohydrates are recognized as differentiation markers and as antigenic determinants. Due to their relevant biological role, carbohydrates are promising candidates for drug design and disease treatment. However, the growing number of human disorders known as congenital disorders of glycosylation that are being identified as resulting from abnormalities in glycan structures and protein glycosylation strongly indicates that a fast development of glycobiology, glycochemistry and glycomedicine is highly desirable. The topics give an overview of different approaches that have been used to date for the design of carbohydrate-based therapeutics; this includes the use of native synthetic carbohydrates, the use of carbohydrate mimics designed on the basis of their native counterpart, the use of carbohydrates as scaffolds and finally the design of glyco-fused therapeutics, one of the most recent approaches. The review covers mainly literature that has appeared since 2000, except for a few papers cited for historical reasons. The reader will gain an overview of the current strategies applied to the design of carbohydrate-based therapeutics; in particular, the advantages/disadvantages of different approaches are highlighted. The topic is presented in a general, basic manner and will hopefully be a useful resource for all readers who are not familiar with it. In addition, in order to stress the potentialities of carbohydrates, several examples of carbohydrate-based marketed therapeutics are given

  19. Effects of iron stress on chromatic adaptation by natural phytoplankton communities in the Southern Ocean

    NARCIS (Netherlands)

    van Leeuwe, M.A.; Timmermans, K.R.; Witte, H.J.; Kraay, G.W.; Veldhuis, M.J.W.; de Baar, H.J.W.

    1998-01-01

    Effects of iron stress on chromatic adaptation were studied in natural phytoplankton communities collected in the Pacific region of the Southern Ocean. Iron enrichment experiments (48 to 72 h) were performed, incubating plankton communities under white, green and blue light respectively, with and

  20. Analysis of the functional diversity of the microbial communities in a ...

    African Journals Online (AJOL)

    The Biolog method was thus evaluated in a paper-mill water system. The influence of the production of various paper grades, biocide combinations and monthly maintenance shut-downs on the functional diversity of the microbial communities were determined using the Biolog technique. The communities in the planktonic ...