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Sample records for bacterioplankton

  1. Circumpolar synchrony in big river bacterioplankton.

    Science.gov (United States)

    Crump, Byron C; Peterson, Bruce J; Raymond, Peter A; Amon, Rainer M W; Rinehart, Amanda; McClelland, James W; Holmes, Robert M

    2009-12-15

    Natural bacterial communities are extremely diverse and highly dynamic, but evidence is mounting that the compositions of these communities follow predictable temporal patterns. We investigated these patterns with a 3-year, circumpolar study of bacterioplankton communities in the six largest rivers of the pan-arctic watershed (Ob', Yenisey, Lena, Kolyma, Yukon, and Mackenzie), five of which are among Earth's 25 largest rivers. Communities in the six rivers shifted synchronously over time, correlating with seasonal shifts in hydrology and biogeochemistry and clustering into three groups: winter/spring, spring freshet, and summer/fall. This synchrony indicates that hemisphere-scale variation in seasonal climate sets the pace of variation in microbial diversity. Moreover, these seasonal communities reassembled each year in all six rivers, suggesting a long-term, predictable succession in the composition of big river bacterioplankton communities. PMID:19940248

  2. Catchment-scale biogeography of riverine bacterioplankton.

    Science.gov (United States)

    Read, Daniel S; Gweon, Hyun S; Bowes, Michael J; Newbold, Lindsay K; Field, Dawn; Bailey, Mark J; Griffiths, Robert I

    2015-02-01

    Lotic ecosystems such as rivers and streams are unique in that they represent a continuum of both space and time during the transition from headwaters to the river mouth. As microbes have very different controls over their ecology, distribution and dispersion compared with macrobiota, we wished to explore biogeographical patterns within a river catchment and uncover the major drivers structuring bacterioplankton communities. Water samples collected across the River Thames Basin, UK, covering the transition from headwater tributaries to the lower reaches of the main river channel were characterised using 16S rRNA gene pyrosequencing. This approach revealed an ecological succession in the bacterial community composition along the river continuum, moving from a community dominated by Bacteroidetes in the headwaters to Actinobacteria-dominated downstream. Location of the sampling point in the river network (measured as the cumulative water channel distance upstream) was found to be the most predictive spatial feature; inferring that ecological processes pertaining to temporal community succession are of prime importance in driving the assemblages of riverine bacterioplankton communities. A decrease in bacterial activity rates and an increase in the abundance of low nucleic acid bacteria relative to high nucleic acid bacteria were found to correspond with these downstream changes in community structure, suggesting corresponding functional changes. Our findings show that bacterial communities across the Thames basin exhibit an ecological succession along the river continuum, and that this is primarily driven by water residence time rather than the physico-chemical status of the river. PMID:25238398

  3. Bacterioplankton dynamics in the Mondego estuary (Portugal)

    Science.gov (United States)

    Bacelar-Nicolau, P.; Nicolau, L. B.; Marques, J. C.; Morgado, F.; Pastorinho, R.; Azeiteiro, U. M.

    2003-05-01

    In this work, the density of bacterioplankton and environmental parameters were monitored over a 11 month period (July 1999-June 2000), and also during one tidal cycle (15 June 2000), at two sampling stations, in the estuary of River Mondego. These data were treated by multivariate analyses methods in order to identify the key factors that control the dynamics of the bacterioplankton in the estuary. Bacterial dynamics were dominated by temporal gradients (annual seasons and tide-related) and less by the spatial structure of the estuary. Three main metabolic groups of bacterioplankton—aerobic heterotrophic bacteria, sulphate-reducing bacteria (SRB) and nitrate-reducing bacteria (NRB)—involved in the cycling of organic matter, were present in the water column of the estuary. Their relative abundance depended on the particular physical, chemical and biological environment. The abundance of aerobic heterotrophic bacteria, during the 11 month study, was modelled as a function of nitrate (the most important variable, with a negative effect), temperature, salinity and pH (with positive effects). SRB appeared to be limited to the water-sediment interface, where concentrations of sulphate and POM were greater. A competition between SRB and NRB for carbon has also been suggested.

  4. Oceanic fronts: transition zones for bacterioplankton community composition.

    Science.gov (United States)

    Baltar, Federico; Currie, Kim; Stuck, Esther; Roosa, Stéphanie; Morales, Sergio E

    2016-02-01

    Oceanic fronts are widespread mesoscale features that exist in the boundary between different water masses. Despite the recognized importance of bacterioplankton (including bacteria and archaea) on the marine biogeochemical cycles and the ubiquitousness of fronts, the effect of frontal zones on the distribution of bacterioplankton community remains unknown. Using 16S rRNA gene sequencing coupled with a high spatial resolution analysis of the physical properties of the water masses, we demonstrate strong shifts in bacterioplankton community composition (BCC) across the subtropical frontal zone off New Zealand. The transition between water masses resulted in a clear modification of the dominant taxa and a significant increase in community dissimilarity. Our results, linking physical oceanography and marine molecular ecology, support the strong role of oceanic frontal zones in delimiting the distribution of bacterioplankton in the ocean. PMID:26636656

  5. Biogeography of bacterioplankton in the tropical seawaters of Singapore.

    Science.gov (United States)

    Lau, Stanley C K; Zhang, Rui; Brodie, Eoin L; Piceno, Yvette M; Andersen, Gary; Liu, Wen-Tso

    2013-05-01

    Knowledge about the biogeography of marine bacterioplankton on the global scale in general and in Southeast Asia in particular has been scarce. This study investigated the biogeography of bacterioplankton community in Singapore seawaters. Twelve stations around Singapore island were sampled on different schedules over 1 year. Using PCR-DNA fingerprinting, DNA cloning and sequencing, and microarray hybridization of the 16S rRNA genes, we observed clear spatial variations of bacterioplankton diversity within the small area of the Singapore seas. Water samples collected from the Singapore Strait (south) throughout the year were dominated by DNA sequences affiliated with Cyanobacteria and Alphaproteobacteria that were believed to be associated with the influx of water from the open seas in Southeast Asia. On the contrary, water in the relatively polluted Johor Strait (north) were dominated by Betaproteobacteria, Gammaproteobacteria, and Bacteroidetes and that were presumably associated with river discharge and the relatively eutrophic conditions of the waterway. Bacterioplankton diversity was temporally stable, except for the episodic surge of Pseudoalteromonas, associated with algal blooms. Overall, these results provide valuable insights into the diversity of bacterioplankton communities in Singapore seas and the possible influences of hydrological conditions and anthropogenic activities on the dynamics of the communities. PMID:23237658

  6. Between-site comparison of freshwater bacterioplankton by DNA hybridization.

    Science.gov (United States)

    Lambert, D L; Taylor, P N; Goulder, R

    1993-11-01

    Natural assemblages of freshwater bacterioplankton in enriched lowland rivers had greater cell-specific metabolic activity than those in gravel-pit ponds. Similarly, cell-specific activity and mean cell Size in calcareous headstreams tended to be greater than in intermittently-acid headstreams on millstone grit. DNA was extracted and purified from bacterioplankton assemblages, and between-site comparisons were made in terms of percentage similarity as indicated by DNA hybridization. Cluster analysis, using percentage-similarity matrices, placed bacterioplankton assemblages from different site types into distinct groups. This suggested that between-site physiological differences were related to intrinsically different bacterial composition rather than to different physiological response to different environmental conditions by essentially similar bacterial assemblages. PMID:24190089

  7. Factors shaping community composition of bacterioplankton

    International Nuclear Information System (INIS)

    The role of nutrients, predation and viral lysis were studied as the major factors shaping community composition of bacterioplankton. The canyon-shaped Rimov reservoir has a strong downstream longitudinal gradient in trophic status and microbial and chemical parameters, with the most pronounced differences between the river inflow and the reservoir dam. We employed an approach allowing simultaneous assessment of the influences of bottom-up and top-down factors. Samples taken from the P-limited dam area were size-fractionated to produce different levels of bacterivory and then incubated in dialysis bags in situ in the sampling area, as well as in the relatively P-enriched river area. The top-down manipulations induced significant changes in bacterial community composition in the more P-limited dam reservoir while predation played a minor role when P limitation was relaxed at the river site. Viral abundance and virus-induced bacterial mortality generally increased along with increasing protistan grazing pressure, and at the river site also with enhanced P-availability. (authors)

  8. Systems Biology and Ecology of Streamlined Bacterioplankton

    Science.gov (United States)

    Giovannoni, S. J.

    2014-12-01

    The salient feature of streamlined cells is their small genome size, but "streamlining" refers more generally to selection that favors minimization of cell size and complexity. The essence of streamlining theory is that selection is most efficient in organisms that have large effective population sizes, and, in nutrient-limited systems, favors cell architecture that minimizes resources required for replication. Regardless of the cause of genome reduction, lost coding potential eventually dictates loss of function, raising the questions, what genome features are expendable, and how do cells become highly successful with a minimal genomic repertoire? One consequence of reductive evolution in streamlined organisms is atypical patterns of prototrophy, for example the recent discovery of a requirement for the thiamin precursor 4-amino-5-hydroxymethyl-2-methylpyrimidine in some plankton taxa. Examples such as this fit within the framework of the Black Queen Hypothesis, which describes genome reduction that results in reliance on community goods and increased community connectivity. Other examples of genome reduction include losses of regulatory functions, or replacement with simpler regulatory systems, and increased metabolic integration. In one such case, in the order Pelagibacterales, the PII system for regulating responses to N limitation has been replaced with a simpler system composed of fewer genes. Both the absence of common regulatory systems and atypical patterns of prototrophy have been linked to difficulty in culturing Pelagibacterales, lending credibility to the idea that streamlining might broadly explain the phenomenon of the uncultured microbial majority. The success of streamlined osmotrophic bacterioplankton suggests that they successfully compete for labile organic matter and capture a large share of this resource, but an alternative theory postulates they are not good resource competitors and instead prosper by avoiding predation. The answers to these

  9. Ambient solar radiation-induced photodamage in marine bacterioplankton

    International Nuclear Information System (INIS)

    There has been much recent concern about the effects of increased UV radiation at certain locations on the earth's surface. There have been extensive studies of ultraviolet radiation effects on phytoplankton and primary production, yet the effects of UVB upon bacterioplankton have been largely overlooked. Bacteria play a central role in the cycling of nutrients and energy flow to higher trophic levels, serving as both mineralizers and secondary producers that are consumed by higher organisms. We have begun to investigate the induction of DNA photodamage by UVB in marine planktonic communities using a highly specific radioimmunoassay to measure cyclobutane pyrimidine dimers in samples collected from the northern Gulf of Mexico. The results demonstrate that direct measures of DNA damage can be made of indigenous planktonic communities and that bacterioplankton are highly susceptible to UVB damage and may serve as a more sensitive indicator of UVR stress than other microorganisms. (Author)

  10. Ambient solar radiation-induced photodamage in marine bacterioplankton

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey, W.H.; Aas, Peter; Lyons, M.M. [University of West Florida, Pensacola, FL (United States). Center for Environmental Diagnostics and Bioremediation; Coffin, R.B. [Environmental Protection Agency, Gulf Breeze, FL (United States); Pledger, R.J.; Mitchell, D.L. [Anderson (M.D.) Cancer Center, Smithville, TX (United States)

    1996-09-01

    There has been much recent concern about the effects of increased UV radiation at certain locations on the earth`s surface. There have been extensive studies of ultraviolet radiation effects on phytoplankton and primary production, yet the effects of UVB upon bacterioplankton have been largely overlooked. Bacteria play a central role in the cycling of nutrients and energy flow to higher trophic levels, serving as both mineralizers and secondary producers that are consumed by higher organisms. We have begun to investigate the induction of DNA photodamage by UVB in marine planktonic communities using a highly specific radioimmunoassay to measure cyclobutane pyrimidine dimers in samples collected from the northern Gulf of Mexico. The results demonstrate that direct measures of DNA damage can be made of indigenous planktonic communities and that bacterioplankton are highly susceptible to UVB damage and may serve as a more sensitive indicator of UVR stress than other microorganisms. (Author).

  11. DNA hybridization to compare species compositions of natural bacterioplankton assemblages.

    OpenAIRE

    Lee, S.; Fuhrman, J A

    1990-01-01

    Little is known about the species composition and variability of natural bacterial communities, mostly because conventional identification requires pure cultures, but less than 1% of active natural bacteria are cultivable. This problem was circumvented by comparing species compositions via hybridization of total DNA of natural bacterioplankton communities for the estimation of the fraction of DNA in common between two samples (similarity). DNA probes that were labeled with 35S by nick transla...

  12. Structuring of bacterioplankton diversity in a large tropical bay.

    Directory of Open Access Journals (Sweden)

    Gustavo B Gregoracci

    Full Text Available Structuring of bacterioplanktonic populations and factors that determine the structuring of specific niche partitions have been demonstrated only for a limited number of colder water environments. In order to better understand the physical chemical and biological parameters that may influence bacterioplankton diversity and abundance, we examined their productivity, abundance and diversity in the second largest Brazilian tropical bay (Guanabara Bay, GB, as well as seawater physical chemical and biological parameters of GB. The inner bay location with higher nutrient input favored higher microbial (including vibrio growth. Metagenomic analysis revealed a predominance of Gammaproteobacteria in this location, while GB locations with lower nutrient concentration favored Alphaproteobacteria and Flavobacteria. According to the subsystems (SEED functional analysis, GB has a distinctive metabolic signature, comprising a higher number of sequences in the metabolism of phosphorus and aromatic compounds and a lower number of sequences in the photosynthesis subsystem. The apparent phosphorus limitation appears to influence the GB metagenomic signature of the three locations. Phosphorus is also one of the main factors determining changes in the abundance of planktonic vibrios, suggesting that nutrient limitation can be observed at community (metagenomic and population levels (total prokaryote and vibrio counts.

  13. Distribution of biomass of heterotrophic bacterioplankton in the Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Distribution, variation and impact factors of biomass of bacterioplankton from April to May 1999in Bohai Sea were studied in DAPI method with epifluorescence microscopy. The biomass in surface waters showed a small day-night variation, varying from 0.13 to 2.51 μg/dm3 with an average of 0.84 μg/dm3. The biomass in bottom waters showed, however, a large variation, changing from 0.15 to 4.18 μg/dm3 with an average of 1.36 μg/dm3. The peak values occurred at 5 and 11 a.m. The bottom water biomass showed a significant correlation with particulate organic carbon (r=0.639, P<0.05). Heterotrophic bacterioplankton biomass was high in nearshore waters and low in offshore areas with a high biomass zone around Huanghe (Yellow) River mouth,showing the same distribution of nutrients. In vertical distribution, heterotrophic bacteria biomass in bottom waters was higher than that in surface water.

  14. Bacterioplankton community variation across river to ocean environmental gradients.

    Science.gov (United States)

    Fortunato, Caroline S; Crump, Byron C

    2011-08-01

    Coastal zones encompass a complex spectrum of environmental gradients that each impact the composition of bacterioplankton communities. Few studies have attempted to address these gradients comprehensively. We generated a synoptic, 16S rRNA gene-based bacterioplankton community profile of a coastal zone by applying the fingerprinting technique denaturing gradient gel electrophoresis to water samples collected from the Columbia River, estuary, and plume, and along coastal transects covering 360 km of the Oregon and Washington coasts and extending to the deep ocean (>2,000 m). Communities were found to cluster into five distinct groups based on location in the system (ANOSIM, p 650 m). Across all environments, abiotic factors (salinity, temperature, depth) explained most of the community variability (ρ = 0.734). But within each coastal environment, biotic factors explained most of the variability. Thus, structuring physical factors in coastal zones, such as salinity and temperature, define the boundaries of many distinct microbial habitats, but within these habitats variability in microbial communities is explained by biological gradients in primary and secondary productivity. PMID:21286702

  15. Detection of bacterioplankton in immersed cadavers using selective agar plates.

    Science.gov (United States)

    Kakizaki, Eiji; Kozawa, Shuji; Tashiro, Noriko; Sakai, Masahiro; Yukawa, Nobuhiro

    2009-04-01

    We measured bacterioplankton in blood from cadavers retrieved from the sea (n=12), near estuaries (n=4), rivers (fresh water, n=8) and from bathtubs (n=4) as well as from non-drowned victims (n=10) discovered near aquatic environments. Blood from 11 victims drowned in seawater developed bioluminescent and/or blue colonies (oxidase test positive) on selective media containing 2-4% NaCl. Homology analyses of the 16S rRNA gene showed that all of them were marine bacteria (genera: Photobacterium, Vibrio, Shewanella, Psychrobacter). Blood from all victims drowned in rivers generated blue colonies on plates containing 3%, but not 4% NaCl. Homology analyses showed that the blue colonies were generated from bacteria that inhabit fresh water (Aeromonas). None of the blood samples from victims that drowned in bathtubs generated bioluminescent and blue colonies. However, all cadavers contained bacteria that produced unstained colonies (Staphylococcus, Bacillus, Enterobacter, Escherichia, etc.). Among non-drowned victims, blood from two gave rise to blue colonies on plates containing Aeromonas; unstained colonies, Citrobacter, Vagococcus, Proteus, Enterobacter). These results suggested that the presence of numerous bacterioplankton in immersed cadavers could support a conclusion of death by drowning. PMID:19261520

  16. Latitudinal patterns in the abundance of major marine bacterioplankton groups

    DEFF Research Database (Denmark)

    Wietz, Matthias; Gram, Lone; Jørgensen, Bo; Schramm, Andreas

    2010-01-01

    This study describes the abundance of major marine bacterioplankton taxa and two bacterial genera (Pseudoalteromonas and Vibrio) in surface seawater at 24 stations around the world. Catalyzed Reporter Deposition-Fluorescence in situ Hybridization (CARD-FISH) showed that Alphaproteobacteria (average...... relative abundance 37%, average absolute abundance 3.7×105 cells mL-1) including SAR11 (30%/3×105), Gammaproteobacteria (14%/1.2×105), and Bacteroidetes (12%/1.3×105) globally dominated the bacterioplankton. The SAR86 clade (4.6%/4.1×104) and Actinobacteria (4.5%/4×104) were detected ubiquitously, whereas...... Archaea were scarce (0.6%/4.2×103). The Roseobacter clade (averaging 3.8%/3.5×104), Pseudoalteromonas (2.6%/2.1×104), and Vibrio (1.5%/1.3×104) showed cosmopolitan occurrence. Principal Component Analysis revealed a latitudinal pattern in bacterial abundances by clustering samples according to lower and...

  17. BACTERIOPLANKTON DYNAMICS IN NORTHERN SAN FRANCISCO BAY: ROLE OF PARTICLE ASSOCIATION AND SEASONAL FRESHWATER FLOW

    Science.gov (United States)

    Bacterioplankton abundance and metabolic characteristics were observed in northern San Francisco Bay, California, during spring and summer 1996 at three sites: Central Bay, Suisun Bay, and the Sacramento River. These sites spanned a salinity gradient from marine to freshwater, an...

  18. Tidal switch on metabolic activity: Salinity induced responses on bacterioplankton metabolic capabilities in a tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Thottathil, S.D.; Balachandran, K.K.; Jayalakshmy, K.V.; Gupta, G.V.M.; Nair, S.

    , Dona Paula 403004, Goa, India Received 5 September 2007; accepted 4 February 2008 Available online 6 March 2008 Abstract ‘‘Biolog’’ plates were used to study the changes in the metabolic capabilities of bacterioplankton over a complete tidal cycle in a... utilization from carbohydrates to amino acids appears to be due to the physiological adaptation or nitrogen limitation of bacterial community with increasing salinity. C211 2008 Elsevier Ltd. All rights reserved. Keywords: bacterioplankton; community; ‘‘Biolog...

  19. Physiological and Metabolic Effects of Carbon Monoxide Oxidation in the Model Marine Bacterioplankton Ruegeria pomeroyi DSS-3

    OpenAIRE

    Cunliffe, Michael

    2013-01-01

    Ruegeria pomeroyi expresses carbon monoxide (CO) dehydrogenase and oxidizes CO; however, CO has no effect on growth. Nuclear magnetic resonance (NMR) spectra showed that CO has no effect on cellular metabolite profiles. These data support ecosystem models proposing that, even though bacterioplankton CO oxidation is biogeochemically significant, it has an insignificant effect on bacterioplankton productivity.

  20. Thermal discharge-created increasing temperatures alter the bacterioplankton composition and functional redundancy.

    Science.gov (United States)

    Xiong, Jinbo; Xiong, Shangling; Qian, Peng; Zhang, Demin; Liu, Lian; Fei, Yuejun

    2016-12-01

    Elevated seawater temperature has altered the coupling between coastal primary production and heterotrophic bacterioplankton respiration. This shift, in turn, could influence the feedback of ocean ecosystem to climate warming. However, little is known about how natural bacterioplankton community responds to increasing seawater temperature. To investigate warming effects on the bacterioplankton community, we collected water samples from temperature gradients (ranged from 15.0 to 18.6 °C) created by a thermal flume of a coal power plant. The results showed that increasing temperatures significantly stimulated bacterial abundance, grazing rate, and altered bacterioplankton community compositions (BCCs). The spatial distribution of bacterioplankton community followed a distance similarity decay relationship, with a turnover of 0.005. A variance partitioning analysis showed that temperature directly constrained 2.01 % variation in BCCs, while temperature-induced changes in water geochemical and grazing rate indirectly accounted for 4.03 and 12.8 % of the community variance, respectively. Furthermore, the relative abundances of 24 bacterial families were linearly increased or decreased (P < 0.05 in all cases) with increasing temperatures. Notably, the change pattern for a given bacterial family was in concert with its known functions. In addition, community functional redundancy consistently decreased along the temperature gradient. This study demonstrates that elevated temperature, combined with substrate supply and trophic interactions, dramatically alters BCCs, concomitant with decreases in functional redundancy. The responses of sensitive assemblages are temperature dependent, which could indicate temperature departures. PMID:27620732

  1. Spatiotemporal distribution of bacterioplankton and bacteriobenthos in the Amur Liman and adjacent sea areas

    Science.gov (United States)

    Karetnikova, E. A.; Garetova, L. A.

    2015-09-01

    Data on the abundance and the ecological-trophic structure of bacterioplankton and bacteriobenthos communities in the Amur Liman and adjacent waters collected in June 2007 have been compared to the relevant data of 2006. Interyear changes of bacterioplankton abundance have been found to depend on the intensity of the Amur River runoff. Correlation analysis has revealed a negative dependence of the abundance of bacterioplankton, bacteriobenthos, and their ecological-trophic groups on water salinity, as well as direct relations between these biotic components and organic matter in water and bottom sediments. The microbiological indicators of water quality ranked the studied waters as classes III-IV in 2006 and as classes II-III in 2007. The high total abundance of bacteriobenthos (109-1010 cells/g) is a result of the functioning of a marginal filter rather than the direct pollution of the liman.

  2. Richness and diversity of bacterioplankton species along an estuarine gradient in Moreton Bay, Australia.

    Science.gov (United States)

    Hewson, Ian; Fuhrman, Jed A

    2004-06-01

    Bacterioplankton community diversity was investigated in the subtropical Brisbane River-Moreton Bay estuary, Australia (27 degrees 25 minutes S, 153 degrees 5 minutes E). Bacterial communities were studied using automated rRNA intergenic spacer analysis (ARISA), which amplifies 16S-23S ribosomal DNA internally transcribed spacer regions from mixed-community DNA and detects the separated products on a fragment analyzer. Samples were collected from eight sites throughout the estuary and east to the East Australian Current (Coral Sea). Bacterioplankton communities had the highest operational taxonomic unit (OTU) richness, as measured by ARISA at eastern bay stations (S [total richness] = 84 to 85 OTU) and the lowest richness in the Coral Sea (S = 39 to 59 OTU). Richness correlated positively with bacterial abundance; however, there were no strong correlations between diversity and salinity, NO(3)(-) and PO(4)(3-) concentrations, or chlorophyll a concentration. Bacterioplankton communities at the riverine stations were different from communities in the bay or Coral Sea. The main differences in OTU richness between stations were in taxa that each represented 0.1% (the detection limit) to 0.5% of the total amplified DNA, i.e., the "tail" of the distribution. We found that some bacterioplankton taxa are specific to distinct environments while others have a ubiquitous distribution from river to sea. Bacterioplankton richness and diversity patterns in the estuary are potentially a consequence of greater niche availability, mixing of local and adjacent environment communities, or intermediate disturbance. Furthermore, these results contrast with previous reports of spatially homogeneous bacterioplankton communities in other coastal waters. PMID:15184140

  3. Effects of large river dam regulation on bacterioplankton community structure.

    Science.gov (United States)

    Ruiz-González, Clara; Proia, Lorenzo; Ferrera, Isabel; Gasol, Josep M; Sabater, Sergi

    2013-05-01

    Large rivers are commonly regulated by damming, yet the effects of such disruption on prokaryotic communities have seldom been studied. We describe the effects of the three large reservoirs of the Ebro River (NE Iberian Peninsula) on bacterioplankton assemblages by comparing several sites located before and after the impoundments on three occasions. We monitored the abundances of several bacterial phylotypes identified by rRNA gene probing, and those of two functional groups (picocyanobacteria and aerobic anoxygenic phototrophic bacteria-AAPs). Much greater numbers of particles colonized by bacteria were found in upstream waters than downstream sites. Picocyanobacteria were found in negligible numbers at most sites, whereas AAPs constituted up to 14% of total prokaryotes, but there was no clear effect of reservoirs on the spatial dynamics of these two groups. Instead, damming caused a pronounced decline in Betaproteobacteria, Gammaproteobacteria and Bacteroidetes from upstream to downstream sites, whereas Alphaproteobacteria and Actinobacteria significantly increased after the reservoirs. Redundancy analysis revealed that conductivity, temperature and dissolved inorganic nitrogen were the environmental predictors that best explained the observed variability in bacterial community composition. Our data show that impoundments exerted significant impacts on bacterial riverine assemblages and call attention to the unforeseen ecological consequences of river regulation. PMID:23278359

  4. Distribution of biomass of heterotrophic bacterioplankton in the Bohai Sea

    Science.gov (United States)

    Bai, Jie; Li, Kuiran; Zhang, Jing; Li, Zhengyan; Gao, Huiwang; Zhang, Haofei

    2005-12-01

    Distribution, variation and impact factors of biomass of bacterioplankton from April to May 1999 in Bohai Sea were studied in DAPI method with epifluorescence microscopy. The biomass in surface waters showed a small day-night variation, varying from 0.13 to 2.51 μg/dm3 with an average of 0.84 μg/dm3. The biomass in bottom waters showed, however, a large variation, changing from 0.15 to 4.18 μg/dm3 with an average of 1.36 μg/dm3. The peak values occurred at 5 and 11 a.m. The bottom water biomass showed a significant correlation with particulate organic carbon ( r=0.639, Pbacterioplankton biomass was high in nearshore waters and low in offshore areas with a high biomass zone around Huanghe (Yellow) River mouth, showing the same distribution of nutrients. In vertical distribution, heterotrophic bacteria biomass in bottom waters was higher than that in surface water.

  5. Energetic differences between bacterioplankton trophic groups and coral reef resistance.

    Science.gov (United States)

    McDole Somera, Tracey; Bailey, Barbara; Barott, Katie; Grasis, Juris; Hatay, Mark; Hilton, Brett J; Hisakawa, Nao; Nosrat, Bahador; Nulton, James; Silveira, Cynthia B; Sullivan, Chris; Brainard, Russell E; Rohwer, Forest

    2016-04-27

    Coral reefs are among the most productive and diverse marine ecosystems on the Earth. They are also particularly sensitive to changing energetic requirements by different trophic levels. Microbialization specifically refers to the increase in the energetic metabolic demands of microbes relative to macrobes and is significantly correlated with increasing human influence on coral reefs. In this study, metabolic theory of ecology is used to quantify the relative contributions of two broad bacterioplankton groups, autotrophs and heterotrophs, to energy flux on 27 Pacific coral reef ecosystems experiencing human impact to varying degrees. The effective activation energy required for photosynthesis is lower than the average energy of activation for the biochemical reactions of the Krebs cycle, and changes in the proportional abundance of these two groups can greatly affect rates of energy and materials cycling. We show that reef-water communities with a higher proportional abundance of microbial autotrophs expend more metabolic energy per gram of microbial biomass. Increased energy and materials flux through fast energy channels (i.e. water-column associated microbial autotrophs) may dampen the detrimental effects of increased heterotrophic loads (e.g. coral disease) on coral reef systems experiencing anthropogenic disturbance. PMID:27097927

  6. Bacterioplankton in an urban river: the effects of a metal-bearing tributary

    Energy Technology Data Exchange (ETDEWEB)

    Milner, C.R.; Goulder, R.

    1984-01-01

    Concentrations of total Cu, Zn, Pb and Cd in the River Aire, West Yorkshire, were elevated close to the confluence of a metal-bearing tributary but rapidly decreased over 500 m downstream. Heterotrophic activity of bacterioplankton appeared to be inhibited adjacent to the confluence, but concentrations of total bacteria, colony-forming units were not depressed. Bacterial variables were not (negatively) correlated with metals (except heterotrophic activity with Cu) but correlations were found between bacteria and other environmental variables. Hence bacterioplankton was probably controlled by environmental variables other than metals originating from the tributary. 29 references, 3 tables.

  7. Effects of UV radiation on DNA photodamage and production in bacterioplankton in the coastal Caribbean Sea

    NARCIS (Netherlands)

    Visser, P.M; Snelder, E; Kop, A.J; Boelen, P.; Buma, A.G.J.; van Duyl, F.C

    1999-01-01

    This study focuses on the effects of ultraviolet radiation (UVR) on bacterioplankton. The effect of different parts of the sunlight spectrum on the leucine and thymidine incorporation and on the induction of DNA damage in natural bacterial populations in the coastal Caribbean Sea off Curacao were in

  8. An ecological assessment of factors determining bacterioplankton dynamics in Tsimlyanskaya reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Katretskii, Y.A.

    1984-07-01

    In this paper the author establishes that the abundance of bacterioplankton in Tsimlyanskaya reservoir is affected by such ecological factors as temperature, quality of organic solutes as well as intrapopulation factors. He concludes that factors dependent on density (consumption by zooplankton, sorption of suspensions) are the main regulators of the volume of bacterial population in the reservoir plankton.

  9. Effect of resource enrichment on grazed and ungrazed bacterioplankton communities of a meso-eutrophic reservoir

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Horňák, Karel; Mašín, Michal; Nedoma, Jiří; Christaki, U.; Weinbauer, M.; Dolan, J.

    Messina: Istituto per l Ambiente Marino Costiero, 2002 - (Giuliano, L.; Yakimov, M.). s. L80 [Symposium on Aquatic Microbial Ecology SAME-8 /8./. 25.10.2002-30.10.2002, Taormina] Institutional research plan: CEZ:AV0Z6017912 Keywords : freshwater reservoir * bacterioplankton communities composition Subject RIV: EE - Microbiology, Virology

  10. Interactions between hydrology and water chemistry shape bacterioplankton biogeography across boreal freshwater networks.

    Science.gov (United States)

    Niño-García, Juan Pablo; Ruiz-González, Clara; Del Giorgio, Paul A

    2016-07-01

    Disentangling the mechanisms shaping bacterioplankton communities across freshwater ecosystems requires considering a hydrologic dimension that can influence both dispersal and local sorting, but how the environment and hydrology interact to shape the biogeography of freshwater bacterioplankton over large spatial scales remains unexplored. Using Illumina sequencing of the 16S ribosomal RNA gene, we investigate the large-scale spatial patterns of bacterioplankton across 386 freshwater systems from seven distinct regions in boreal Québec. We show that both hydrology and local water chemistry (mostly pH) interact to shape a sequential structuring of communities from highly diverse assemblages in headwater streams toward larger rivers and lakes dominated by fewer taxa. Increases in water residence time along the hydrologic continuum were accompanied by major losses of bacterial richness and by an increased differentiation of communities driven by local conditions (pH and other related variables). This suggests that hydrology and network position modulate the relative role of environmental sorting and mass effects on community assembly by determining both the time frame for bacterial growth and the composition of the immigrant pool. The apparent low dispersal limitation (that is, the lack of influence of geographic distance on the spatial patterns observed at the taxonomic resolution used) suggests that these boreal bacterioplankton communities derive from a shared bacterial pool that enters the networks through the smallest streams, largely dominated by mass effects, and that is increasingly subjected to local sorting of species during transit along the hydrologic continuum. PMID:26849312

  11. Contrasted effects of diversity and immigration on ecological insurance in marine bacterioplankton communities.

    Directory of Open Access Journals (Sweden)

    Thierry Bouvier

    Full Text Available The ecological insurance hypothesis predicts a positive effect of species richness on ecosystem functioning in a variable environment. This effect stems from temporal and spatial complementarity among species within metacommunities coupled with optimal levels of dispersal. Despite its importance in the context of global change by human activities, empirical evidence for ecological insurance remains scarce and controversial. Here we use natural aquatic bacterial communities to explore some of the predictions of the spatial and temporal aspects of the ecological insurance hypothesis. Addressing ecological insurance with bacterioplankton is of strong relevance given their central role in fundamental ecosystem processes. Our experimental set up consisted of water and bacterioplankton communities from two contrasting coastal lagoons. In order to mimic environmental fluctuations, the bacterioplankton community from one lagoon was successively transferred between tanks containing water from each of the two lagoons. We manipulated initial bacterial diversity for experimental communities and immigration during the experiment. We found that the abundance and production of bacterioplankton communities was higher and more stable (lower temporal variance for treatments with high initial bacterial diversity. Immigration was only marginally beneficial to bacterial communities, probably because microbial communities operate at different time scales compared to the frequency of perturbation selected in this study, and of their intrinsic high physiologic plasticity. Such local "physiological insurance" may have a strong significance for the maintenance of bacterial abundance and production in the face of environmental perturbations.

  12. Contrasted effects of diversity and immigration on ecological insurance in marine bacterioplankton communities.

    Science.gov (United States)

    Bouvier, Thierry; Venail, Patrick; Pommier, Thomas; Bouvier, Corinne; Barbera, Claire; Mouquet, Nicolas

    2012-01-01

    The ecological insurance hypothesis predicts a positive effect of species richness on ecosystem functioning in a variable environment. This effect stems from temporal and spatial complementarity among species within metacommunities coupled with optimal levels of dispersal. Despite its importance in the context of global change by human activities, empirical evidence for ecological insurance remains scarce and controversial. Here we use natural aquatic bacterial communities to explore some of the predictions of the spatial and temporal aspects of the ecological insurance hypothesis. Addressing ecological insurance with bacterioplankton is of strong relevance given their central role in fundamental ecosystem processes. Our experimental set up consisted of water and bacterioplankton communities from two contrasting coastal lagoons. In order to mimic environmental fluctuations, the bacterioplankton community from one lagoon was successively transferred between tanks containing water from each of the two lagoons. We manipulated initial bacterial diversity for experimental communities and immigration during the experiment. We found that the abundance and production of bacterioplankton communities was higher and more stable (lower temporal variance) for treatments with high initial bacterial diversity. Immigration was only marginally beneficial to bacterial communities, probably because microbial communities operate at different time scales compared to the frequency of perturbation selected in this study, and of their intrinsic high physiologic plasticity. Such local "physiological insurance" may have a strong significance for the maintenance of bacterial abundance and production in the face of environmental perturbations. PMID:22701572

  13. Annual dynamics of North Sea bacterioplankton: seasonal variability superimposes short-term variation.

    Science.gov (United States)

    Lucas, Judith; Wichels, Antje; Teeling, Hanno; Chafee, Meghan; Scharfe, Mirco; Gerdts, Gunnar

    2015-09-01

    The dynamics of coastal marine microbial communities are driven by seasonally changing abiotic and biotic factors as well as by rapidly occurring short-term changes such as river fresh water influxes or phytoplankton blooms. We examined the variability of the free-living bacterioplankton at Helgoland Roads (German Bight, North Sea) over a period of one year with high temporal and taxonomic resolution to reveal variation patterns and main influencing factors. 16S rRNA gene tag sequencing of the bacterioplankton community hints at annual recurrence and resilience of few main taxa belonging to Alphaproteobacteria, Betaproteobacteria, Flavobacteriia, Acidimicrobiia and Thermoplasmata. Multiple regression analyses with various environmental factors revealed changes in water current patterns and resulting phytoplankton blooms as the main driving factors for short-term variation and temperature as the overlying factor for seasonal variation. Comparison of bacterioplankton successions during spring and summer phytoplankton blooms revealed the same dominating Flavobacteriia operational taxonomic units (OTUs) but shifts in Roseobacter related OTUs (Alphaproteobacteria) and SAR92 clade members (Gammaproteobacteria). Network analysis suggests that during spring and summer phytoplankton blooms temperature-dependent guilds are formed. In conclusion, our data imply that short-term bacterioplankton successions in response to phytoplankton blooms are indirectly affected by temperature, which is a major niche-defining factor in the German Bight. PMID:26298013

  14. Marine bacterioplankton community turnover within seasonally hypoxic waters of a subtropical sound

    DEFF Research Database (Denmark)

    Parsons, Rachel J.; Nelson, Craig E.; Carlson, Craig A.;

    2015-01-01

    , Bermuda during the 6-week annual transition from a strongly stratified water column with suboxic and high-pCO2 bottom waters to a fully mixed and ventilated state during 2008. A suite of culture-independent methods provided a quantitative spatiotemporal characterization of bacterioplankton community...

  15. Phylogenetic shifts of bacterioplankton community composition along Pearl Estuary: the potential impact of hypoxia and nutrients

    Directory of Open Access Journals (Sweden)

    Jiwen eLiu

    2015-02-01

    Full Text Available The significance of salinity in shaping bacterial communities dwelling in estuarine areas has been well documented. However, the influences of other environmental factors such as dissolved oxygen and nutrients in governing bacterioplankton communities inhabited in local estuarine regions remain elusive. Here, bacterioplankton community structure of surface and bottom waters from eight sites along Pearl Estuary were characterized with 16S rRNA genes pyrosequencing. The bacterioplankton community dendrogram partitioned the samples into three groups, i.e., whole water column of freshwater sites, surface water of saltwater sites and bottom water of saltwater sites. In the saltwater sites, Synechococcus dominated the surface water while Oceanospirillales, SAR11 and SAR406 were prevalent in the bottom water. Betaproteobacteria was abundant in the freshwater sites, with no significant difference between water layers. Moreover, occurrence of phylogenetic shifts in taxa affiliated to the same clade was also detected. Dissolved oxygen explained most of the bacterial community variation in the redundancy analysis targeting only freshwater sites, whereas nutrients and salinity explained most of the variation across all the samples in Pearl Estuary. Methylophilales (mainly PE2 clade was positively correlated to dissolved oxygen, whereas Rhodocyclales (mainly R.12up clade was negatively correlated. Moreover, high nutrient inputs to the freshwater area of Pearl Estuary have shifted the bacterial communities towards copiotrophic groups, such as Sphingomonadales. The present study provides a clear outline of bacterioplankton communities in two regions of a subtropical estuary and demonstrates that the overall nutrients and freshwater hypoxia play important roles in determining bacterioplankton compositions

  16. Global patterns of marine bacterioplankton diversity and characterisation of bioactive Vibrionaceae isolates

    DEFF Research Database (Denmark)

    Wietz, Matthias

    The purpose of the present study was to analyze the composition of marine bacterial communities around the world, and to investigate bacterial isolates regarding the production of antibiotics. This included molecular analyses of marine bacterioplankton, as well as culture-based studies of marine....... Quantitative community analyses showed latitudinal patterns in bacterial distribution, revealing significantly different relative abundances of Bacteroidetes, unclassified Bacteria and Vibrio between warmer and colder oceans. Absolute cell numbers of most bacterial groups were positively correlated...... bacterial isolates with antagonistic activity. The work was based on samples collected during the Galathea 3 and LOMROG-II marine research expeditions that have explored many different oceanic regions worldwide. A molecular survey of marine bacterioplankton at 24 worldwide stations investigated...

  17. Verrucomicrobia Are Candidates for Polysaccharide-Degrading Bacterioplankton in an Arctic Fjord of Svalbard

    OpenAIRE

    Cardman, Z.; C. Arnosti; Durbin, A.; Ziervogel, K.; Cox, C; A. D. Steen; Teske, A

    2014-01-01

    In Arctic marine bacterial communities, members of the phylum Verrucomicrobia are consistently detected, although not typically abundant, in 16S rRNA gene clone libraries and pyrotag surveys of the marine water column and in sediments. In an Arctic fjord (Smeerenburgfjord) of Svalbard, members of the Verrucomicrobia, together with Flavobacteria and smaller proportions of Alpha- and Gammaproteobacteria, constituted the most frequently detected bacterioplankton community members in 16S rRNA gen...

  18. Bacterioplankton in the Baltic Sea : influence of allochthonous organic matter and salinity

    OpenAIRE

    Figueroa, Daniela

    2016-01-01

    Climate change is expected to increase the precipitation ~30% in higher latitudes during the next century, increasing the land runoff via rivers to aquatic ecosystems. The Baltic Sea will receive higher river discharges, accompanied by larger input of allochthonous dissolved organic matter (DOM) from terrestrial ecosystems. The salinity will decrease due to freshwater dilution. The allochthonous DOM constitute a potential growth substrate for microscopic bacterioplankton and phytoplankton, wh...

  19. Impact of solar radiation on bacterioplankton in Laguna Vilama, a hypersaline Andean lake (4650 m)

    Science.gov (United States)

    FaríAs, MaríA. Eugenia; FernáNdez-Zenoff, Verónica; Flores, Regina; OrdóñEz, Omar; EstéVez, Cristina

    2009-06-01

    Laguna Vilama is a hypersaline Lake located at 4660 m altitude in the northwest of Argentina high up in the Andean Puna. The impact of ultraviolet (UV) radiation on bacterioplankton was studied by collecting samples at different times of the day. Molecular analysis (DGGE) showed that the bacterioplankton community is characterized by Gamma-proteobacteria (Halomonas sp., Marinobacter sp.), Alpha-proteobacteria (Roseobacter sp.), HGC (Agrococcus jenensis and an uncultured bacterium), and CFB (uncultured Bacteroidetes). During the day, minor modifications in bacterial diversity such as intensification of Bacteroidetes' signal and an emergence of Gamma-proteobacteria (Marinobacter flavimaris) were observed after solar exposure. DNA damage, measured as an accumulation of Cyclobutane Pyrimidine Dimers (CPDs), in bacterioplankton and naked DNA increased from 100 CPDs MB-1 at 1200 local time (LT) to 300 CPDs MB-1 at 1600 LT, and from 80 CPDs MB-1 at 1200 LT to 640 CPDs MB-1 at 1600 LT, respectively. In addition, pure cultures of Pseudomonas sp. V1 and Brachybacterium sp. V5, two bacteria previously isolated from this environment, were exposed simultaneously with the community, and viability of both strains diminished after solar exposure. No CPD accumulation was observed in either of the exposed cultures, but an increase in mutagenesis was detected in V5. Of both strains only Brachybacterium sp. V5 showed CPD accumulation in naked DNA. These results suggest that the bacterioplankton community is well adapted to this highly solar irradiated environment showing little accumulation of CPDs and few changes in the community composition. They also demonstrate that these microorganisms contain efficient mechanisms against UV damage.

  20. Diel changes in bacteriochlorophyll a concentration suggest rapid bacterioplankton cycling in the Baltic Sea

    Czech Academy of Sciences Publication Activity Database

    Koblížek, Michal; Ston-Egiert, J.; Sagan, S.; Kolber, Z. S.

    2005-01-01

    Roč. 51, - (2005), s. 353-361. ISSN 0168-6496 R&D Projects: GA ČR GP206/03/P079; GA MŠk LN00A141 Institutional research plan: CEZ:AV0Z5020903 Keywords : Aerobic anoxygenic photoheterotrophs * Bacteria l mortality * Bacterioplankton turnover Subject RIV: EE - Microbiology, Virology Impact factor: 2.787, year: 2005

  1. Away from darkness: A review on the effects of solar radiation on heterotrophic bacterioplankton activity

    OpenAIRE

    CLARARUIZ GONZALEZ; Gasol, Josep M.

    2013-01-01

    Heterotrophic bacterioplankton are main consumers of dissolved organic matter in aquatic ecosystems, including the sunlit upper layers of the ocean and freshwater bodies. Their well-known sensitivity to ultraviolet radiation (UVR), together with some recently discovered mechanisms bacteria have evolved to benefit from photosynthetically available radiation (PAR), suggest that natural sunlight plays a relevant, yet difficult to predict role in modulating bacterial biogeochemical functions in a...

  2. Away from darkness: a review on the effects of solar radiation on heterotrophic bacterioplankton activity

    OpenAIRE

    Ruiz-González, Clara; Simó, Rafel; Sommaruga, Ruben; Gasol, Josep M.

    2013-01-01

    Heterotrophic bacterioplankton are main consumers of dissolved organic matter (OM) in aquatic ecosystems, including the sunlit upper layers of the ocean and freshwater bodies. Their well-known sensitivity to ultraviolet radiation (UVR), together with some recently discovered mechanisms bacteria have evolved to benefit from photosynthetically available radiation (PAR), suggest that natural sunlight plays a relevant, yet difficult to predict role in modulating bacterial biogeochemical functions...

  3. Identification of polyamine-responsive bacterioplankton taxa in South Atlantic Bight.

    Science.gov (United States)

    Lu, Xinxin; Sun, Shulei; Hollibaugh, James T; Mou, Xiaozhen

    2015-12-01

    Putrescine and spermidine are short-chained aliphatic polyamines (PAs) that are ubiquitously distributed in seawater. These compounds may be important sources of dissolved organic carbon and nitrogen for marine bacterioplankton. Here, we used pyrotag sequencing to quantify the response of bacterioplankton to putrescine and spermidine amendments in microcosms established using surface waters collected at various stations in the South Atlantic Bight in October 2011. Our analysis showed that PA-responsive bacterioplankton consisted of bacterial taxa that are typically dominant in marine systems. Rhodobacteraceae (Alphaproteobacteria) was the taxon most responsive to PA additions at the nearshore site. Gammaproteobacteria of the families Piscirickettsiaceae; Vibrionaceae; and Vibrionaceae and Pseudoalteromonadaceae, were the dominant PA-responsive taxa in samples from the river-influenced coastal station, offshore station and open ocean station, respectively. The spatial variability of PA-responsive taxa may be attributed to differences in composition of the initial bacterial community and variations of in situ physiochemical conditions among sites. Our results also provided the first empirical evidence that Gammaproteobacteria might play an important role in PA transformation in marine systems. PMID:26109269

  4. Tracking differential incorporation of dissolved organic carbon types among diverse lineages of Sargasso Sea bacterioplankton.

    Science.gov (United States)

    Nelson, Craig E; Carlson, Craig A

    2012-06-01

    Bacterioplankton are the primary trophic conduit for dissolved organic carbon (DOC) and linking community structure with DOC utilization is central to understanding global carbon cycling. We coupled stable isotope probing (SIP) with 16S rRNA pyrosequencing in dark seawater culture experiments on euphotic and mesopelagic communities from the Sargasso Sea. Parallel cultures were amended with equimolar quantities of four DO(13) C substrates to simultaneously evaluate community utilization and population-specific incorporation. Of the substrates tested - two cyanobacterial products (exudates or lysates from a culture of Synechococcus) and two defined monosaccharides (glucose or gluconic acid) - the cyanobacterial exudates were incorporated by the greatest diversity of oligotrophic bacterioplankton populations in surface waters, including taxa from > 10 major subclades within the Flavobacteria, Actinobacteria, Verrucomicrobia and Proteobacteria (including SAR11). In contrast, the monosaccharide glucose was not incorporated by any taxa belonging to extant oligotrophic oceanic clades. Conversely, proteobacterial copiotrophs, which were rare in the ambient water (< 0.1% of sequences), grew rapidly on all DOC amendments at both depths, but with different substrate preferences among lineages. We present a new analytical framework for using SIP to detect DOC incorporation across diverse oligotrophic bacterioplankton and discuss implications for the ecology of bacterial-DOC interactions among populations of diverging trophic strategies. PMID:22507662

  5. Understanding diversity patterns in bacterioplankton communities from a sub-Antarctic peatland.

    Science.gov (United States)

    Quiroga, María Victoria; Valverde, Angel; Mataloni, Gabriela; Cowan, Don

    2015-06-01

    Bacterioplankton communities inhabiting peatlands have the potential to influence local ecosystem functions. However, most microbial ecology research in such wetlands has been done in ecosystems (mostly peat soils) of the Northern Hemisphere, and very little is known of the factors that drive bacterial community assembly in other regions of the world. In this study, we used high-throughput sequencing to analyse the structure of the bacterial communities in five pools located in a sub-Antarctic peat bog (Tierra del Fuego, Argentina), and tested for relationships between bacterial communities and environmental conditions. Bacterioplankton communities in peat bog pools were diverse and dominated by members of the Proteobacteria, Actinobacteria, Bacteroidetes and Verrucomicrobia. Community structure was largely explained by differences in hydrological connectivity, pH and nutrient status (ombrotrophic versus minerotrophic pools). Bacterioplankton communities in ombrotrophic pools showed phylogenetic clustering, suggesting a dominant role of deterministic processes in shaping these assemblages. These correlations between habitat characteristics and bacterial diversity patterns provide new insights into the factors regulating microbial populations in peatland ecosystems. PMID:25727763

  6. Spatially uniform but temporally variable bacterioplankton in a semi-enclosed coastal area.

    Science.gov (United States)

    Meziti, Alexandra; Kormas, Konstantinos A; Moustaka-Gouni, Maria; Karayanni, Hera

    2015-07-01

    Studies focusing on the temporal and spatial dynamics of bacterioplankton communities within littoral areas undergoing direct influences from the coast are quite limited. In addition, they are more complicated to resolve compared to communities in the open ocean. In order to elucidate the effects of spatial vs. temporal variability on bacterial communities in a highly land-influenced semi-enclosed gulf, surface bacterioplankton communities from five coastal sites in Igoumenitsa Gulf (Ionian Sea, Greece) were analyzed over a nine-month period using 16S rDNA 454-pyrosequencing. Temporal differences were more pronounced than spatial ones, with lower diversity indices observed during the summer months. During winter and early spring, bacterial communities were dominated by SAR11 representatives, while this pattern changed in May when they were abruptly replaced by members of Flavobacteriales, Pseudomonadales, and Alteromonadales. Additionally, correlation analysis showed high negative correlations between the presence of SAR11 OTUs in relation to temperature and sunlight that might have driven, directly or indirectly, the disappearance of these OTUs in the summer months. The dominance of SAR11 during the winter months further supported the global distribution of the clade, not only in the open-sea, but also in coastal systems. This study revealed that specific bacteria exhibited distinct succession patterns in an anthropogenic-impacted coastal system. The major bacterioplankton component was represented by commonly found marine bacteria exhibiting seasonal dynamics, while freshwater and terrestrial-related phylotypes were absent. PMID:25976032

  7. Marine bacterioplankton community turnover within seasonally hypoxic waters of a subtropical sound: Devil's Hole, Bermuda.

    Science.gov (United States)

    Parsons, Rachel J; Nelson, Craig E; Carlson, Craig A; Denman, Carmen C; Andersson, Andreas J; Kledzik, Andrew L; Vergin, Kevin L; McNally, Sean P; Treusch, Alexander H; Giovannoni, Stephen J

    2015-10-01

    Understanding bacterioplankton community dynamics in coastal hypoxic environments is relevant to global biogeochemistry because coastal hypoxia is increasing worldwide. The temporal dynamics of bacterioplankton communities were analysed throughout the illuminated water column of Devil's Hole, Bermuda during the 6-week annual transition from a strongly stratified water column with suboxic and high-pCO2 bottom waters to a fully mixed and ventilated state during 2008. A suite of culture-independent methods provided a quantitative spatiotemporal characterization of bacterioplankton community changes, including both direct counts and rRNA gene sequencing. During stratification, the surface waters were dominated by the SAR11 clade of Alphaproteobacteria and the cyanobacterium Synechococcus. In the suboxic bottom waters, cells from the order Chlorobiales prevailed, with gene sequences indicating members of the genera Chlorobium and Prosthecochloris--anoxygenic photoautotrophs that utilize sulfide as a source of electrons for photosynthesis. Transitional zones of hypoxia also exhibited elevated levels of methane- and sulfur-oxidizing bacteria relative to the overlying waters. The abundance of both Thaumarcheota and Euryarcheota were elevated in the suboxic bottom waters (> 10(9) cells l(-1)). Following convective mixing, the entire water column returned to a community typical of oxygenated waters, with Euryarcheota only averaging 5% of cells, and Chlorobiales and Thaumarcheota absent. PMID:24589037

  8. [The distribution of bacterioplankton and mesozooplankton biomass in the White and Barents Seas coastal water].

    Science.gov (United States)

    Chikin, S M; Tarasova, N A; Saralov, A I; Bannikova, O M

    2003-01-01

    The total population density and the biomass of bacterioplankton, mesozooplankton, and phosphate-accumulating bacteria (PAB) were estimated during the 2000-2001 summer-autumn seasons in the coastal waters of the White and Barents Seas, which are subjects to the action of tidal and sea currents, the inflow of riverine waters, and anthropogenic impact. In the shallow estuarine waters with salinities of 6.5-32@1000 near the Chernaya, Pesha, and Pechora River mouths, the population of PAB fluctuated from 0.1 to 9.1 million cells/ml (0-36% of the total bacterial population). In pelagic seawaters, which are low in phosphates (12-50 micrograms/l) and are characterized by an increased iron/phosphorus ratio (2.0-3.6), bacterioplankton amounted to 0.1-1.6 million cells/ml and was mainly represented by small organisms with a volume of 0.08-0.15 micron 3, commonly lacking intracellular polyphosphates. In the pelagic zone of the Barents Sea, the biomass of mesozooplankton (Bz) was comparable with that of bacterioplankton (Bb = 39-175 mg/m3), the Bb/Bz ratio being 1.4-4.6. Off the Varandeiskii, Pechora, and Kolguyev oil terminals, Bb increased to 155-300 mg/m3 and the Bb/Bz ratio rose to 1.4 to 50.3 (with an average value of 20.9), presumably due to the severe anthropogenic impact on these waters. In this case, the dense population of bacterioplankton (0.9-7.6 million cells/ml) was mainly represented by large cells (0.12-0.76 micron 3 in volume), most of which (3-43% of the total bacterioplankton population) contained polyphosphates. The chemical composition of these waters was characterized by an elevated content of the total phosphorus (65-128 micrograms/l) and by a low iron/phosphorus ratio (0.9-1.2). PMID:12751250

  9. Effect of the cyanobacterium Anabaena spiroides Klebahn on the quantity of bacterioplankton in water of varied trophicity.

    Science.gov (United States)

    Czeczuga, B; Chomutowska, H

    2000-01-01

    The authors investigated the effect of the cyanobacterium Anabaena spiroides on the quantity of bacterioplankton in water of varied trophicity. The cyanobacterium Anabaena spiroides, introduced to the polluted water of the river Biała has the strongest effect on bacterioplankton--the number of bacteria decreases to 31.78%. The spherical:cylindrical ratio changes in favour of the latter when affected by the cyanobacterium. This is the most pronounced in the river Biała, where spherical:cylindrical changes from 1:0.88 to 1:1.96. Anabaena spiroides exerts the most significant effect on the quantity of bacterioplankton in lake Sniardwy and pond Fosa after 24 hours, and in the other water bodies after 72 hours following the introduction of the cyanobacterium. PMID:11712443

  10. Spatial and temporal dynamics of phytoplankton and bacterioplankton biomass in Sanya Bay, northern South China Sea.

    Science.gov (United States)

    Zhou, Weihua; Li, Tao; Cai, Chuanghua; Huang, Liangmin; Wang, Hankui; Xu, Jirong; Dong, Junde; Zhang, Si

    2009-01-01

    The composition of phytoplankton and the dynamics of phytoplankton and bacterioplankton biomass (PB and BB, respectively) of Sanya Bay, South China Sea, were determined. A total of 168 species (67 genera) phytoplankton were identified, including Bacillariophyta (diatom, 128 species), Pyrrophyta (35 species), Cyanophyta (3 species), and Chrysophyta (2 species). Annual average abundance of phytoplankton was 1.2 x 10(7) cells/m3, with the highest abundance in autumn, and the lowest in summer. Annual average diversity index (H') and evenness (J) values were 3.96 and 0.70, respectively. Average chlorophyll-a was 2.5 mg/m3, and the average PB was 124 mg C/m3, with the highest value in autumn. Surface PB was higher than the bottom, except for summer. Annual mean bacterioplankton abundance and BB were 6.9 x 10(11) cells/m3 and 13.8 mg C/m3, respectively. The highest BB was found in summer, followed by winter, spring, and autumn. Surface BB was higher than bottom all year round. The spatial distribution patterns of PB and BB were very similar with the highest biomass in the estuary, and decreased seaward, primarily due to the terrestrial input from the Sanya River and influx of oceanic water. The main factor influencing PB and BB was dissolved inorganic nitrogen (DIN). Other factors such as temperature, which is above 22 degrees C throughout the year, had a negligible impact. The correlation between BB and PB was significant (P bacterioplankton. PMID:20108660

  11. Annual Bacterioplankton Biomasses and Productivities in a Temperate West Coast Canadian Fjord

    OpenAIRE

    Albright, L. J.; McCrae, S. K.

    1987-01-01

    Bacterioplankton numbers, biomasses, and productivities, as well as chlorophyll a concentrations and phytoplankton productivities, were assayed from 1 March 1984 to 12 August 1985 through a 250-m-deep seawater column in Howe Sound, a temperate fjord-sound on the southern coast of British Columbia, Canada. Primary production during this 18-month period was 845 g of C m−2. Bacterial production was assayed over this same period as 193 g of C m−2 (thymidine incorporation) and 77 g of C m−2 (frequ...

  12. Snowmelt-driven changes in dissolved organic matter and bacterioplankton communities in the Heilongjiang watershed of China.

    Science.gov (United States)

    Qiu, Linlin; Cui, Hongyang; Wu, Junqiu; Wang, Baijie; Zhao, Yue; Li, Jiming; Jia, Liming; Wei, Zimin

    2016-06-15

    Bacterioplankton plays a significant role in the circulation of materials and ecosystem function in the biosphere. Dissolved organic matter (DOM) from dead plant material and surface soil leaches into water bodies when snow melts. In our study, water samples from nine sampling sites along the Heilongjiang watershed were collected in February and June 2014 during which period snowmelt occurred. The goal of this study was to characterize changes in DOM and bacterioplankton community composition (BCC) associated with snowmelt, the effects of DOM, environmental and geographical factors on the distribution of BCC and interactions of aquatic bacterioplankton populations with different sources of DOM in the Heilongjiang watershed. BCC was measured by denaturing gradient gel electrophoresis (DGGE). DOM was measured by excitation-emission matrix (EEM) fluorescence spectroscopy. Bacterioplankton exhibited a distinct seasonal change in community composition due to snowmelt at all sampling points except for EG. Redundancy analysis (RDA) indicated that BCC was more closely related to DOM (Components 1 and 4, dissolved organic carbon, biochemical oxygen demand and chlorophyll a) and environmental factors (water temperature and nitrate nitrogen) than geographical factors. Furthermore, DOM had a greater impact on BCC than environmental factors (29.80 vs. 15.90% of the variation). Overall, spring snowmelt played an important role in altering the quality and quantity of DOM and BCC in the Heilongjiang watershed. PMID:26974572

  13. Diurnal variations in depth profiles of UV-induced DNA damage and inhibition of bacterioplankton production in tropical coastal waters

    NARCIS (Netherlands)

    Visser, PM; Poos, JJ; Scheper, BB; Boelen, P; van Duyl, FC

    2002-01-01

    In this study, diurnal changes in bacterial production and DNA damage in bacterio-plankton (measured as cyclobutane pyrimidine dimers, CPDs) incubated in bags at different depths in tropical coastal waters were investigated. The DNA damage and inhibition of the bacterial production was highest at th

  14. Macrophytes and periphyton carbon subsidies to bacterioplankton and zooplankton in a shallow eutrophic lake in tropical China

    DEFF Research Database (Denmark)

    de Kluijver, A.; Ning, J.; Liu, Z.;

    2015-01-01

    The subsidy of carbon derived from macrophytes and associated periphyton to bacterioplankton and zooplankton in subtropical shallow eutrophic Huizhou West Lake in China was analyzed using carbon stable isotope signatures. A restored part of the lake dominated by macrophytes was compared with an...

  15. .i.Candidatus./i. Planktophila limnetica, an actinobacterium representing one of the most numerically important taxa in freshwater bacterioplankton

    Czech Academy of Sciences Publication Activity Database

    Jezbera, Jan; Sharma, A. K.; Brandt, U.; Doolittle, W.F.; Hahn, M.W.

    2009-01-01

    Roč. 59, č. 11 (2009), s. 2864-2869. ISSN 1466-5026 Institutional research plan: CEZ:AV0Z60170517 Keywords : Actinobacteria * Planktophila * freshwater * bacterioplankton Subject RIV: EE - Microbiology, Virology Impact factor: 2.113, year: 2009

  16. Response of rare, common and abundant bacterioplankton to anthropogenic perturbations in a Mediterranean coastal site.

    Science.gov (United States)

    Baltar, Federico; Palovaara, Joakim; Vila-Costa, Maria; Salazar, Guillem; Calvo, Eva; Pelejero, Carles; Marrasé, Cèlia; Gasol, Josep M; Pinhassi, Jarone

    2015-06-01

    Bacterioplankton communities are made up of a small set of abundant taxa and a large number of low-abundant organisms (i.e. 'rare biosphere'). Despite the critical role played by bacteria in marine ecosystems, it remains unknown how this large diversity of organisms are affected by human-induced perturbations, or what controls the responsiveness of rare compared to abundant bacteria. We studied the response of a Mediterranean bacterioplankton community to two anthropogenic perturbations (i.e. nutrient enrichment and/or acidification) in two mesocosm experiments (in winter and summer). Nutrient enrichment increased the relative abundance of some operational taxonomic units (OTUs), e.g. Polaribacter, Tenacibaculum, Rhodobacteraceae and caused a relative decrease in others (e.g. Croceibacter). Interestingly, a synergistic effect of acidification and nutrient enrichment was observed on specific OTUs (e.g. SAR86). We analyzed the OTUs that became abundant at the end of the experiments and whether they belonged to the rare (1% relative abundance) fractions. Most of the abundant OTUs at the end of the experiments were abundant, or at least common, in the original community of both experiments, suggesting that ecosystem alterations do not necessarily call for rare members to grow. PMID:26032602

  17. Spatial variability overwhelms seasonal patterns in bacterioplankton communities across a river to ocean gradient.

    Science.gov (United States)

    Fortunato, Caroline S; Herfort, Lydie; Zuber, Peter; Baptista, Antonio M; Crump, Byron C

    2012-03-01

    Few studies of microbial biogeography address variability across both multiple habitats and multiple seasons. Here we examine the spatial and temporal variability of bacterioplankton community composition of the Columbia River coastal margin using 16S amplicon pyrosequencing of 300 water samples collected in 2007 and 2008. Communities separated into seven groups (ANOSIM, Priver, estuary, plume, epipelagic, mesopelagic, shelf bottom (depth850 m). The ordination of these samples was correlated with salinity (ρ=-0.83) and depth (ρ=-0.62). Temporal patterns were obscured by spatial variability among the coastal environments, and could only be detected within individual groups. Thus, structuring environmental factors (for example, salinity, depth) dominate over seasonal changes in determining community composition. Seasonal variability was detected across an annual cycle in the river, estuary and plume where communities separated into two groups, early year (April-July) and late year (August-Nov), demonstrating annual reassembly of communities over time. Determining both the spatial and temporal variability of bacterioplankton communities provides a framework for modeling these communities across environmental gradients from river to deep ocean. PMID:22011718

  18. Bacterioplankton and bacteriobenthos of the Amur estuary and the adjacent areas in the Summer of 2006

    Science.gov (United States)

    Karetnikova, E. A.; Garetova, L. A.

    2009-06-01

    This work presents the results of the study of the plankton and benthic microbiocenoses of the Amur estuary. It is shown that the distribution of the total abundance and indicator groups of the bacteriobenthos are characterized by stronger heterogeneity compared with the bacterioplankton and that it depends on the Amur river drainage and the bottom type. The river drainage helps by increasing the overall bacterioplankton abundance in the near-mouth part of the estuary. Microorganisms utilizing low concentrations of OM play a major role in the processes of the OM utilization in the water and bottom sediments. Saprophytic bacteria play a significant role in the OM utilization only in the water at certain sampling sites in the Tatarskiy Strait and Sakhalin Bay and in the bottom sediments taken in the mouth part of the estuary. Some parts of the estuary subject to organic contamination are found according to the microbiological characteristics. It is shown that the fluctuation of the salinity leads to a change of the share of bacteria with different food demands in the microbial community.

  19. Spatial-Temporal Changes of Bacterioplankton Community along an Exhorheic River.

    Science.gov (United States)

    Ma, Lili; Mao, Guannan; Liu, Jie; Gao, Guanghai; Zou, Changliang; Bartlam, Mark G; Wang, Yingying

    2016-01-01

    To date, few aquatic microbial ecology studies have discussed the variability of the microbial community in exorheic river ecosystems on both the spatial and seasonal scales. In this study, we examined the spatio-temporal variation of bacterioplankton community composition in an anthropogenically influenced exorheic river, the Haihe River in Tianjin, China, using pyrosequencing analysis of 16S rRNA genes. It was verified by one-way ANOVA that the spatial variability of the bacterioplankton community composition over the whole river was stronger than the seasonal variation. Salinity was a major factor leading to spatial differentiation of the microbial community structure into riverine and estuarial parts. A high temperature influence on the seasonal bacterial community variation was only apparent within certain kinds of environments (e.g., the riverine part). Bacterial community richness and diversity both exhibited significant spatial changes, and their seasonal variations were completely different in the two environments studied here. Furthermore, riverine bacterial community assemblages were subdivided into urban and rural groups due to changes in the nutritional state of the river. In addition, the nutrient-loving group including Limnohabitans, Hydrogenophaga, and Polynucleobacter were abundant in the urbanized Haihe River, indicating the environmental factors in these anthropogenic waterbodies heavily influence the core freshwater community composition. PMID:26973627

  20. Bacterioplankton abundance, biomass and production in a Brazilian coastal lagoon and in two German lakes

    Directory of Open Access Journals (Sweden)

    FURTADO ANDRÉ L. S.

    2001-01-01

    Full Text Available The bacterioplanktonic abundance, biomass, and production within a tropical lagoon (Cabiúnas, Brazil and two temperate lakes (Stechlin and Dagow, Germany were compared. Bacterial abundance and production were significantly different among the three water bodies. The lowest bacterial production ( 0.8mug C l-1 d-1 was observed in the tropical Cabiúnas Lagoon despite its higher mean temperature and dissolved organic carbon concentration. Highest bacterioplankton abundance ( 2.6 x 10(9 cells l-1 and production ( 68.5mug C l-1 d-1 were measured in eutrophic Lake Dagow. In oligotrophic Lake Stechlin, the lowest bacterial biomass ( 48.05mug C l-1 was observed because of lower bacterial biovolume ( 0.248mum³ and lower bacterial abundance. Bacterial populations in the temperate lakes show higher activity (production/biomass ratio than in the tropical lagoon. The meaning of isotopic dilution and leucine incorporation by non-bacterial micro-organisms were evaluated in the oligotrophic temperate system. Leucine uptake by non-bacterial micro-organisms did not have significant influence on bacterial production.

  1. Response of marine bacterioplankton pH homeostasis gene expression to elevated CO2

    Science.gov (United States)

    Bunse, Carina; Lundin, Daniel; Karlsson, Christofer M. G.; Akram, Neelam; Vila-Costa, Maria; Palovaara, Joakim; Svensson, Lovisa; Holmfeldt, Karin; González, José M.; Calvo, Eva; Pelejero, Carles; Marrasé, Cèlia; Dopson, Mark; Gasol, Josep M.; Pinhassi, Jarone

    2016-05-01

    Human-induced ocean acidification impacts marine life. Marine bacteria are major drivers of biogeochemical nutrient cycles and energy fluxes; hence, understanding their performance under projected climate change scenarios is crucial for assessing ecosystem functioning. Whereas genetic and physiological responses of phytoplankton to ocean acidification are being disentangled, corresponding functional responses of bacterioplankton to pH reduction from elevated CO2 are essentially unknown. Here we show, from metatranscriptome analyses of a phytoplankton bloom mesocosm experiment, that marine bacteria responded to lowered pH by enhancing the expression of genes encoding proton pumps, such as respiration complexes, proteorhodopsin and membrane transporters. Moreover, taxonomic transcript analysis showed that distinct bacterial groups expressed different pH homeostasis genes in response to elevated CO2. These responses were substantial for numerous pH homeostasis genes under low-chlorophyll conditions (chlorophyll a 20 μg l-1) were low. Given that proton expulsion through pH homeostasis mechanisms is energetically costly, these findings suggest that bacterioplankton adaptation to ocean acidification could have long-term effects on the economy of ocean ecosystems.

  2. Short-Term Dynamics of North Sea Bacterioplankton-Dissolved Organic Matter Coherence on Molecular Level.

    Science.gov (United States)

    Lucas, Judith; Koester, Irina; Wichels, Antje; Niggemann, Jutta; Dittmar, Thorsten; Callies, Ulrich; Wiltshire, Karen H; Gerdts, Gunnar

    2016-01-01

    Remineralization and transformation of dissolved organic matter (DOM) by marine microbes shape the DOM composition and thus, have large impact on global carbon and nutrient cycling. However, information on bacterioplankton-DOM interactions on a molecular level is limited. We examined the variation of bacterial community composition (BCC) at Helgoland Roads (North Sea) in relation to variation of molecular DOM composition and various environmental parameters on short-time scales. Surface water samples were taken daily over a period of 20 days. Bacterial community and molecular DOM composition were assessed via 16S rRNA gene tag sequencing and ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), respectively. Environmental conditions were driven by a coastal water influx during the first half of the sampling period and the onset of a summer phytoplankton bloom toward the end of the sampling period. These phenomena led to a distinct grouping of bacterial communities and DOM composition which was particularly influenced by total dissolved nitrogen (TDN) concentration, temperature, and salinity, as revealed by distance-based linear regression analyses. Bacterioplankton-DOM interaction was demonstrated in strong correlations between specific bacterial taxa and particular DOM molecules, thus, suggesting potential specialization on particular substrates. We propose that a combination of high resolution techniques, as used in this study, may provide substantial information on substrate generalists and specialists and thus, contribute to prediction of BCC variation. PMID:27014241

  3. Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

    Institute of Scientific and Technical Information of China (English)

    ZENG Yinxin; LI Huirong; YU Yong; CHEN Bo; ZHENG Tianling

    2007-01-01

    A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and β-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSw10175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus Shewanella dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria ( > 99% ),but also between polar marine bacteria and bacteria from other aquatic environments ( ≥98.8% ) , including temperate ocean,deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.

  4. Influence of macrophyte decomposition on growth rate and community structure of Okefenokee Swamp bacterioplankton

    International Nuclear Information System (INIS)

    Dissolved substances released during decomposition of the white water lily (Nymphaea odorata) can alter the growth rate of Okefenokee Swamp bacterioplankton. In microcosm experiments dissolved compounds released bacterioplankton, followed by a period of intense bacterial growth. Rates of [3H]thymidine incorporation and turnover of dissolved D-glucose were depressed by over 85%, 3 h after the addition of Nymphaea leachates to microcosms containing Okefenokee Swamp water. Bacterial activity subsequently recovered; after 20 h [3H]thymidine incorporation in leachate-treated microcosms was 10-fold greater than that in control microcosms. The recovery of activity was due to a shift in the composition of the bacterial population toward resistance to the inhibitory compounds present in Nymphaea leachates. Inhibitory compounds released during the decomposition of aquatic macrophytes thus act as selective agents which alter the community structure of the bacterial population with respect to leachate resistance. Soluble compounds derived from macrophyte decomposition influence the rate of bacterial secondary production and the availability of microbial biomass to microconsumers

  5. Short-term dynamics of North Sea bacterioplankton-dissolved organic matter coherence on molecular level

    Directory of Open Access Journals (Sweden)

    Judith eLucas

    2016-03-01

    Full Text Available Remineralisation and transformation of dissolved organic matter (DOM by marine microbes shape the DOM composition and thus, have large impact on global carbon and nutrient cycling. However, information on bacterioplankton-DOM interactions on a molecular level is limited. We examined the variation of bacterial community composition at Helgoland Roads (North Sea in relation to variation of molecular DOM composition and various environmental parameters on short-time scales. Surface water samples were taken daily over a period of twenty days. Bacterial community and molecular DOM composition were assessed via 16S rRNA gene tag sequencing and ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS, respectively. Environmental conditions were driven by a coastal water influx during the first half of the sampling period and the onset of a summer phytoplankton bloom towards the end of the sampling period. These phenomena led to a distinct grouping of bacterial communities and DOM composition which was particularly influenced by total dissolved nitrogen concentration, temperature and salinity, as revealed by distance-based linear regression analyses. Bacterioplankton-DOM interaction was demonstrated in strong correlations between specific bacterial taxa and particular DOM molecules, thus, suggesting potential specialization on particular substrates. We propose that a combination of high resolution techniques, as used in this study, may provide substantial information on substrate generalists and specialists and thus, contribute to prediction of bacterial community composition variation.

  6. Temporal Patterns in Bacterioplankton Community Composition in Three Reservoirs of Similar Trophic Status in Shenzhen, China

    Science.gov (United States)

    Li, Jiancheng; Chen, Cheng; Lu, Jun; Lei, Anping; Hu, Zhangli

    2016-01-01

    The bacterioplankton community composition’s (BCC) spatial and temporal variation patterns in three reservoirs (Shiyan, Xikeng, and LuoTian Reservoir) of similar trophic status in Bao’an District, Shenzhen (China), were investigated using PCR amplification of the 16S rDNA gene and the denaturing gradient gel electrophoresis (DGGE) techniques. Water samples were collected monthly in each reservoir during 12 consecutive months. Distinct differences were detected in band number, pattern, and density of DGGE at different sampling sites and time points. Analysis of the DGGE fingerprints showed that changes in the bacterial community structure mainly varied with seasons, and the patterns of change indicated that seasonal forces might have a more significant impact on the BCC than eutrophic status in the reservoirs, despite the similar Shannon-Weiner index among the three reservoirs. The sequences obtained from excised bands were affiliated with Cyanobacteria, Firmicutes, Bacteriodetes, Acidobacteria, Actinobacteria, Planctomycetes, and Proteobacteria. PMID:27322295

  7. Distribution patterns of bacterioplankton and chlorophyll-a in the German Wadden Sea

    Science.gov (United States)

    Poremba, K.; Tillmann, U.; Hesse, K.-J.

    1999-08-01

    In a first synoptic evaluation, the temporal and spatial distribution of bacterioplankton and chlorophyll-a were determined in the German Wadden Sea. Three surveys were undertaken in winter, spring, and summer of 1994 using up to eight ships simultaneously between the river Ems and Sylt island. Despite intensive hydrodynamic mixing of the Wadden Sea water, spatial gradients were obvious. The abundance of bacterioplankton ranged from 0.4 to 26×105 ml-1 and chlorophyll-a varied between <0.1 and 79 µg l-1. In winter, relatively homogeneous distribution patterns of both parameters with small gradients were found. Highest chlorophyll-a values connected with a highly patchy structure were observed in spring, while in summer both total chlorophyll-a values and the complexity of the distribution pattern had decreased. In contrast, bacterial numbers increased steadily from January to July with the highest bacterial densities and greatest patchiness observed in summer. Moreover, in some regions of the Wadden Sea, a trophic succession of algae as carbon producers and bacteria as consumers was evident. Correlation analysis verified the relationship between bacteria and chlorophyll a, indicating bottom-up control of bacterial abundance in the northern part of the German Wadden Sea. Since the observed regression slope is remarkably low (0.12-0.46) compared to literature values (0.5-0.8), we suggest that the link between phytoplankton and bacteria found here is a special characteristic of the Wadden Sea as a transition zone between the coastal region and the outer North Sea.

  8. Successive changes in bacterioplankton communities in the River Rhine after copper additions

    Energy Technology Data Exchange (ETDEWEB)

    Tubbing, D.M.J.; Admiraal, W. [National Institute of Public Health and Environmental Protection, Bilthoven (Netherlands); Katako, A. [International Institute for Infrastructural, Hydraulic and Environmental Engineering, Delft (Netherlands)

    1995-09-01

    The sensitivity of bacterioplankton to copper was analyzed to see whether initial steps in the selection of cooper-tolerant life-forms in mixed populations of bacteria were accompanied by changes in basic metabolic parameters. Analysis took place by measuring the incorporation of [{sup 3}H]thymidine and [{sup 3}H]leucine, and the hydrolysis of leucyl-{beta}-naphthylamide over a period of 4 d. In acute toxicity tests the radiochemically determined parameters showed the same sensitivities to copper, whereas in the enzyme test the dose-response curve had a much lower slope, indicating less sensitivity. Marked differences were observed in the susceptibility of the different processes after prolonged exposure to copper. Incorporation of [{sup 3}H]thymidine, [{sup 3}H]leucine, and proteolytic activity changed substantially during exposure to concentrations as low as 2 to 31 {micro}g Cu L{sup {minus}1}. Higher copper concentrations 126--1,000 {micro}g Cu L{sup {minus}1} led in the course of 24 to 48 h to the development of a bacterial community with a higher overall copper tolerance. In winter, these successive events in bacterial populations were observed in the absence of substantial populations of algae or zooplankton. In summer, the metabolic changes in bacterioplankton expose to copper were strongly affected by the poisoning of other organisms, notably algae, and the subsequent release of organic material. Thus, moderate copper concentrations alter the metabolic profile of bacterial communities, probably as an initial step in the selection of tolerant life-forms.

  9. Attached and Free-Floating Bacterioplankton in Howe Sound, British Columbia, a Coastal Marine Fjord-Embayment

    OpenAIRE

    Albright, L. J.; McCrae, S. K.; May, B. E.

    1986-01-01

    Factors which influence the attachment of bacterioplankton to particles (including phytoplankton) were investigated by using (i) water samples removed from a coastal temperate fjord over an annual cycle and (ii) unialgal cultures of Prorocentrum minimum, Dunaliella tertiolecta, and Skeletonema costatum. Silt and salinity levels in this fjord seawater did not appear to influence bacterial attachment, but the percent attached bacteria was inversely related to both chlorophyll a concentrations a...

  10. Analysis of composition and structure of coastal to mesopelagic bacterioplankton communities in the northern Gulf of Mexico

    OpenAIRE

    GaryMKing; BradleyTolar

    2013-01-01

    16S rRNA gene amplicons were pyrosequenced to assess bacterioplankton community composition, diversity and phylogenetic community structure for 17 stations in the northern Gulf of Mexico (nGoM) sampled in March 2010. Statistical analyses showed that samples from depths ≤ 100 m differed distinctly from deeper samples. SAR 11 α-Proteobacteria and Bacteroidetes dominated communities at depths ≤ 100 m, which were characterized by high α-Proteobacteria/γ-Proteobacteria ratios (α/γ > 1.7). Th...

  11. Modelling the impact of riverine DON removal by marine bacterioplankton on primary production in the Arctic Ocean

    Science.gov (United States)

    Le Fouest, V.; Manizza, M.; Tremblay, B.; Babin, M.

    2015-06-01

    The planktonic and biogeochemical dynamics of the Arctic shelves exhibit a strong variability in response to Arctic warming. In this study, we employ a biogeochemical model coupled to a pan-Arctic ocean-sea ice model (MITgcm) to elucidate the processes regulating the primary production (PP) of phytoplankton, bacterioplankton (BP), and their interactions. The model explicitly simulates and quantifies the contribution of usable dissolved organic nitrogen (DON) drained by the major circum-Arctic rivers to PP and BP in a scenario of melting sea ice (1998-2011). Model simulations suggest that, on average between 1998 and 2011, the removal of usable riverine dissolved organic nitrogen (RDON) by bacterioplankton is responsible for a ~ 26% increase in the annual BP for the whole Arctic Ocean. With respect to total PP, the model simulates an increase of ~ 8% on an annual basis and of ~ 18% in summer. Recycled ammonium is responsible for the PP increase. The recycling of RDON by bacterioplankton promotes higher BP and PP, but there is no significant temporal trend in the BP : PP ratio within the ice-free shelves over the 1998-2011 period. This suggests no significant evolution in the balance between autotrophy and heterotrophy in the last decade, with a constant annual flux of RDON into the coastal ocean, although changes in RDON supply and further reduction in sea-ice cover could potentially alter this delicate balance.

  12. Modeling the impact of riverine DON removal by marine bacterioplankton on primary production in the Arctic Ocean

    Science.gov (United States)

    Le Fouest, V.; Manizza, M.; Tremblay, B.; Babin, M.

    2014-12-01

    The planktonic and biogeochemical dynamics of the Arctic shelves exhibit a strong variability in response to Arctic warming. In this study, in order to elucidate on the processes regulating the production of phytoplankton (PP) and bacterioplankton (BP) and their interactions, we employ a biogeochemical model coupled to a pan-Arctic ocean-sea ice model (MITgcm) to explicitly simulate and quantify the contribution of usable dissolved organic nitrogen (DON) drained by the major circum-Arctic rivers on PP and BP in a scenario of melting sea ice (1998-2011). Model simulations suggest that on average between 1998 and 2011, the removal of usable RDON by bacterioplankton is responsible of a ~26% increase of the annual BP for the whole Arctic Ocean. With respect to total PP, the model simulates an increase of ~8% on an annual basis and of ~18% in summer. Recycled ammonium is responsible for the PP increase. The recycling of RDON by bacterioplankton promotes higher BP and PP but there is no significant temporal trend in the BP : PP ratio within the ice-free shelves over the 1998-2011 period. This suggests no significant evolution in the balance between autotrophy and heterotrophy in the last decade with a constant annual flux of RDON into the coastal ocean although changes in RDON supply and further reduction in sea ice cover could potentially alter this delicate balance.

  13. Submerged macrophytes shape the abundance and diversity of bacterial denitrifiers in bacterioplankton and epiphyton in the Shallow Fresh Lake Taihu, China.

    Science.gov (United States)

    Fan, Zhou; Han, Rui-Ming; Ma, Jie; Wang, Guo-Xiang

    2016-07-01

    nirK and nirS genes are important functional genes involved in the denitrification pathway. Recent studies about these two denitrifying genes are focusing on sediment and wastewater microbe. In this study, we conducted a comparative analysis of the abundance and diversity of denitrifiers in the epiphyton of submerged macrophytes Potamogeton malaianus and Ceratophyllum demersum as well as in bacterioplankton in the shallow fresh lake Taihu, China. Results showed that nirK and nirS genes had significant different niches in epiphyton and bacterioplankton. Bacterioplankton showed greater abundance of nirK gene in terms of copy numbers and lower abundance of nirS gene. Significant difference in the abundance of nirK and nirS genes also existed between the epiphyton from different submerged macrophytes. Similar community diversity yet different community abundance was observed between epiphytic bacteria and bacterioplankton. No apparent seasonal variation was found either in epiphytic bacteria or bacterioplankton; however, environmental parameters seemed to have direct relevancy with nirK and nirS genes. Our study suggested that submerged macrophytes have greater influence than seasonal parameters in shaping the presence and abundance of bacterial denitrifiers. Further investigation needs to focus on the potential contact and relative contribution between denitrifiers and environmental factors. PMID:27048324

  14. Jellyfish-associated bacterial communities and bacterioplankton in Indonesian Marine lakes.

    Science.gov (United States)

    Cleary, Daniel F R; Becking, Leontine E; Polónia, Ana R M; Freitas, Rossana M; Gomes, Newton C M

    2016-05-01

    In the present study, we compared communities of bacteria in two jellyfish species (the 'golden' jellyfishMastigiascf.papuaand the box jellyfishTripedaliacf.cystophora) and water in three marine lakes located in the Berau region of northeastern Borneo, Indonesia. Jellyfish-associated bacterial communities were compositionally distinct and less diverse than bacterioplankton communities. Alphaproteobacteria, Gammaproteobacteria, Synechococcophycidae and Flavobacteriia were the most abundant classes in water. Jellyfish-associated bacterial communities were dominated by OTUs assigned to the Gammaproteobacteria (family Endozoicimonaceae), Mollicutes, Spirochaetes and Alphaproteobacteria (orders Kiloniellales and Rhodobacterales). Mollicutes were mainly restricted toMastigiaswhereas Spirochaetes and the order Kiloniellales were most abundant inTripedaliahosts. The most abundant OTU overall in jellyfish hosts was assigned to the family Endozoicimonaceae and was highly similar to organisms in Genbank obtained from various hosts including an octocoral, bivalve and fish species. Other abundant OTUs included an OTU assigned to the order Entomoplasmatales and mainly found inMastigiashosts and OTUs assigned to the Spirochaetes and order Kiloniellales and mainly found inTripedaliahosts. The low sequence similarity of the Entomoplasmatales OTU to sequences in Genbank suggests that it may be a novel lineage inhabitingMastigiasand possibly restricted to marine lakes. PMID:27004797

  15. Inorganic phosphorus stimulation of bacterioplankton production in a meso-eutrophic lake

    International Nuclear Information System (INIS)

    Experiments were conducted to determine whether production of heterotrophic bacterioplankton in a small meso-eutrophic lake was influenced by the dissolved inorganic phosphorus (DIP) supply. DIP may indirectly limit bacterial production by limiting phytoplankton, which in turn may limit the carbon available to bacteria. Direct DIP limitation of bacteria occurs where the availability of DIP for bacteria is insufficient to maintain growth. This work examined direct DIP limitation of bacteria by removing phytoplankton and incubating flasks with or without added P in the dark. Bacterial production was measured via the rate of incorporation of [3H]thymidine ([3H]TdR) into DNA. Bacterial abundance was followed with epifluorescent direct counts. Rates of [3H]TdR incorporation were significantly greater in flasks with added DIP, and changes in cell abundances generally paralleled increases in [3H]TdR incorporation. Even very small additions of P (0.05 μM) were sufficient to stimulate production. DIP addition to whole lakewater also stimulated [3H]TdR incorporation relative to that in zero-addition controls, but there was not a concurrent increase in bacterial cell numbers. The stimulation of [3H]TdR incorporation after DIP addition to whole lakewater was significantly less than the stimulation due to DIP addition to 1-μm-pore-size-filtered lakewater. In this study, addition of DIP causes as much as an eightfold stimulation of [3H]TdR incorporation

  16. Tips and tricks for high quality MAR-FISH preparations: focus on bacterioplankton analysis.

    Science.gov (United States)

    Alonso, Cecilia

    2012-12-01

    The combination of microautoradiography and fluorescence in situ hybridization (MAR-FISH) is a powerful technique for tracking the incorporation of radiolabelled compounds by specific bacterial populations at a single cell resolution. It has been widely applied in aquatic microbial ecology as a tool to unveil key ecophysiological features, shedding light on relevant ecological issues such as bacterial biomass production, the role of different bacterioplankton groups in the global carbon and sulphur cycle, and, at the same time, providing insights into the life styles and niche differentiation of cosmopolitan members of the aquatic microbial communities. Despite its great potential, its application has remained restricted to a few laboratories around the world, in part due to its reputation as a "difficult technique". Therefore, the objective of this minireview is to highlight the impact of MAR-FISH application on aquatic microbial ecology, and also to provide basic concepts, as well as practical tips, for processing MAR-FISH preparations, thus aiming to contribute to a more widespread application of this powerful method. PMID:22502862

  17. The hidden seasonality of the rare biosphere in coastal marine bacterioplankton

    KAUST Repository

    Alonso-Sáez, Laura

    2015-04-08

    Summary: Rare microbial taxa are increasingly recognized to play key ecological roles, but knowledge of their spatio-temporal dynamics is lacking. In a time-series study in coastal waters, we detected 83 bacterial lineages with significant seasonality, including environmentally relevant taxa where little ecological information was available. For example, Verrucomicrobia had recurrent maxima in summer, while the Flavobacteria NS4, NS5 and NS2b clades had contrasting seasonal niches. Among the seasonal taxa, only 4 were abundant and persistent, 20 cycled between rare and abundant and, remarkably, most of them (59) were always rare (contributing <1% of total reads). We thus demonstrate that seasonal patterns in marine bacterioplankton are largely driven by lineages that never sustain abundant populations. A fewer number of rare taxa (20) also produced episodic \\'blooms\\', and these events were highly synchronized, mostly occurring on a single month. The recurrent seasonal growth and loss of rare bacteria opens new perspectives on the temporal dynamics of the rare biosphere, hitherto mainly characterized by dormancy and episodes of \\'boom and bust\\', as envisioned by the seed-bank hypothesis. The predictable patterns of seasonal reoccurrence are relevant for understanding the ecology of rare bacteria, which may include key players for the functioning of marine ecosystems. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. Annual dynamics of bacterioplankton assemblages in the Gulf of Trieste (Northern Adriatic Sea).

    Science.gov (United States)

    Celussi, Mauro; Cataletto, Bruno

    2007-12-30

    Bacterioplankton community diversity was investigated monthly in coastal waters of the Gulf of Trieste (NE Adriatic Sea) throughout 2003. Superficial bacterial assemblages of two differently freshwater influenced stations were studied using PCR-DGGE fingerprinting techniques. Bacterial genetic diversity of the sampled area, as estimates of the number of DGGE bands was high (36-64) compared to that reported in other studies employing this fingerprint technique. The similarity index (Sorensen Index) between assemblages showed a defined operational taxonomic units (OTUs) succession pattern in the more typically marine station with stable winter communities and quickly changing summer ones. On the contrary in the station affected by riverine inputs no clear pattern was detected. In both sites, according to cluster analyses performed on the DGGE banding pattern, three seasonal assemblages were identified: winter-spring, summer and fall. Sequence analysis of fifty-six among the brightest gel bands led to the observation of bacteria affiliated to Gram positive, Cyanobacteria, Cytophaga-Flavobacteria-Bacteroides (CFB) lineages and the alpha-, gamma- and delta- subdivisions of the Proteobacteria. Gamma-Proteobacteria constituted the main fraction (60%) of sequences in the more typically marine station, whereas the river-influenced station was characterised by more heterogeneous assemblages (39% alpha-Proteobacteria, 32% Flavobacteria). PMID:17728077

  19. Phylogenetic diversity, composition and distribution of bacterioplankton community in the Dongjiang River, China.

    Science.gov (United States)

    Liu, Zhenghui; Huang, Shaobin; Sun, Guoping; Xu, Zhencheng; Xu, Meiying

    2012-04-01

    Bacterioplankton community compositions in the Dongjiang River were characterized using denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene clone library construction. Water samples in nine different sites were taken along the mainstem and three tributaries. In total, 24 bands from DGGE gels and 406 clones from the libraries were selected and sequenced, subsequently analyzed for the bacterial diversity and composition of those microbial communities. Bacterial 16S rRNA gene sequences from freshwater bacteria exhibited board phylogenetic diversity, including sequences representing the Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Actinobacteria, Bacteriodetes, Verrucomicrobia, and candidate division TM7. Members of Betaproteobacteria group were the most dominant in all sampling sites, followed by Gammaproteobacteria, Alphaproteobacteria, and Actinobacteria. DGGE profiles and the ∫-LIBSHUFF analysis revealed similar patterns of bacterial diversity among most sampling sites, while spatial distribution variances existed in all sites along the river basin. Statistical analysis showed that bacterial species distribution strongly correlated with environmental variables, such as nitrate and ammonia, suggesting that nitrogen nutrients may shape the microbial community structure and composition in the Dongjiang River. This study had important implications for the comparison with other rivers elsewhere and contributed to the growing data set on the factors that structure bacterial communities in freshwater ecosystems. PMID:22133045

  20. [Bacterioplankton and bacteriobenthos of some floodplain lakes in the course of the lower Amur river].

    Science.gov (United States)

    Dziuban, A N

    2002-01-01

    The main structural and functional characteristics of bacterioplankton and bacteriobenthos of three lakes in the lower course of the Amur River are presented: the total number of bacteria (TNB), biomass, the numbers of bacteria of certain aerobic and anaerobic groups; the intensities of methanogenesis (MG), methane oxidation (MO), assimilation of 14C-compounds, sulfate reduction (SR); and gross estimate of organic matter decomposition (D). Depending on the reservoir type and the anthropogenic load, TNB constituted (2.27 to 16.1) x 10(6) cells/ml in water and (1.06 to 10.35) x 10(9) cells/ml in sediments; MO was 0 to 0.28 ml CH4/(1 day) in water and 0 to 8.4 ml CH4/(dm3 day) in sediments; MG in sediments was 0.001 to 40 ml CH4/(dm3 day); SR varied from 0.001 to 24.8 mg S/(dm3 day); D was 0.3 to 25 g C/(m2 day) in water and 0.2 to 4.9 g C/(m2 day) in sediments. The role of anaerobic microbial processes of organic matter decomposition was shown to increase with an increase in the anthropogenic load, attaining 95% of the total D in the ecosystem of an accumulating pond. PMID:12244728

  1. Longitudinal and depth variation of bacterioplankton productivity and related factors in a temperate estuary

    Science.gov (United States)

    Peierls, Benjamin L.; Paerl, Hans W.

    2011-11-01

    Bacterioplankton productivity (BP) spatial variation was investigated in relation to potential resources, including primary productivity and dissolved organic matter, in the micro-tidal Neuse River-Pamlico Sound estuarine system, North Carolina, USA. Estuarine BP was predicted to correlate with the trophic gradient, decreasing along the salinity gradient in parallel with the decrease in organic matter and primary productivity. This prediction was tested over four years at spatial scales ranging from kilometers to meters along the riverine axis and with depth. The general pattern of BP across the salinity gradient was unimodal and matched the phytoplankton patterns in peak location and variability. Peak locations varied with discharge, especially in 2003 when above average discharge moved peaks downstream. Spatial coherence of BP with other variables was much less at short time scales. The effect of temperature, nutrients, and phytoplankton on BP varied by location, especially fresh versus brackish stations, although only temperature explained more than 20% of the BP variation. Depth variation of BP was as great as longitudinal variation and bottom samples were often higher than surface. BP was strongly correlated with particulate organic carbon at the pycnocline and bottom, highlighting the importance of particulate matter as a resource. Station-averaged BP and phytoplankton data corresponded well with two published meta-analyses, although the offset of the freshwater station suggested longitudinal differences in community composition or resource availability.

  2. Diversity of bacterioplankton in the surface seawaters of Drake Passage near the Chinese Antarctic station.

    Science.gov (United States)

    Xing, Mengxin; Li, Zhao; Wang, Wei; Sun, Mi

    2015-07-01

    The determination of relative abundances and distribution of different bacterial groups is a critical step toward understanding the functions of various bacteria and its surrounding environment. Few studies focus on the taxonomic composition and functional diversity of microbial communities in Drake Passage. In this study, marine bacterioplankton communities from surface seawaters at five locations in Drake Passage were examined by 16S rRNA gene sequence analyses. The results indicated that psychrophilic bacteria were the most abundant group in Drake Passage, and mainly made up of Bacillus, Aeromonas, Psychrobacter, Pseudomonas and Halomonas. Diversity analysis showed that surface seawater communities had no significant correlation with latitudinal gradient. Additionally, a clear difference among five surface seawater communities was evident, with 1.8% OTUs (only two) belonged to Bacillus consistent across five locations and 71% OTUs (80) existed in only one location. However, the few cosmopolitans had the largest population sizes. Our results support the hypothesis that the dominant bacterial groups appear to be analogous between geographical sites, but significant differences may be detected among rare bacterial groups. The microbial diversity of surface seawaters would be liable to be affected by environmental factors. PMID:26184094

  3. Linking the patterns of change in composition and function in bacterioplankton successions along environmental gradients.

    Science.gov (United States)

    Comte, Jérôme; del Giorgio, Paul A

    2010-05-01

    The connections that exist between the composition of bacterial communities and their functional attributes are still a matter of intense debate, despite over a decade of intense studies. Here we explored three different facets of the links that may exist between bacterioplankton compositional and functional successions that occurred along the water flow path in a complex watershed in southern Quebec. We analyzed the correlation between composition and function in terms of their absolute patterns, and in terms of their rates of change relative to transit time in environmental transitions, and relative to shifts in resources along the same transitions. Our results showed that the absolute patterns in bacterial community composition (BCC, using DGGE [denaturing gradient gel electrophoresis] profiles) and functional capacities (FC, using BIOLOG profiles) were not correlated, but that the rates of change in BCC and FC along the transitions were strongly correlated to each other. Further, we observed that the strength and shape of the relationship between the changes in BCC and FC varied relative to the type and intensity of gradient considered. Collectively, these results showed that BCC and FC are strongly related but in a very dynamic manner, such that their absolute patterns do not appear to be connected. This in turn suggests a high level of functional redundancy that occurs both within the existing community and in the meta-community from which phylotypes are selected to occupy the new niches that are created along the transitions. PMID:20503878

  4. Low Taxon Richness of Bacterioplankton in High-Altitude Lakes of the Eastern Tibetan Plateau, with a Predominance of Bacteroidetes and Synechococcus spp.▿ †

    OpenAIRE

    Xing, Peng; Hahn, Martin W.; Wu, Qinglong L.

    2009-01-01

    Plankton samples were collected from six remote freshwater and saline lakes located at altitudes of 3,204 to 4,718 m and 1,000 km apart within an area of ca. 1 million km2 on the eastern Tibetan Plateau to comparatively assess how environmental factors influence the diversity of bacterial communities in high-altitude lakes. The composition of the bacterioplankton was investigated by analysis of large clone libraries of 16S rRNA genes. Comparison of bacterioplankton diversities estimated for t...

  5. Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study

    OpenAIRE

    Riebesell, U.; Engel, A.; K. G. Schulz; Sperling, M.; C. Borchard; J. Piontek

    2012-01-01

    The effect of elevated seawater carbon dioxide (CO2) on the activity of a natural bacterioplankton community in an Arctic fjord system was investigated by a mesocosm perturbation study in the frame of the European Project on Ocean Acidification (EPOCA). A pCO2 range of 175–1085 μatm was set up in nine mesocosms deployed in the Kongsfjorden (Svalbard). The bacterioplankton communities responded to rising chlorophyll a concentrations after a lag phase of only a few days with increasing ...

  6. Free-Living and Particle-Associated Bacterioplankton in Large Rivers of the Mississippi River Basin Demonstrate Biogeographic Patterns.

    Science.gov (United States)

    Jackson, Colin R; Millar, Justin J; Payne, Jason T; Ochs, Clifford A

    2014-12-01

    The different drainage basins of large rivers such as the Mississippi River represent interesting systems in which to study patterns in freshwater microbial biogeography. Spatial variability in bacterioplankton communities in six major rivers (the Upper Mississippi, Missouri, Illinois, Ohio, Tennessee, and Arkansas) of the Mississippi River Basin was characterized using Ion Torrent 16S rRNA amplicon sequencing. When all systems were combined, particle-associated (>3 μm) bacterial assemblages were found to be different from free-living bacterioplankton in terms of overall community structure, partly because of differences in the proportional abundance of sequences affiliated with major bacterial lineages (Alphaproteobacteria, Cyanobacteria, and Planctomycetes). Both particle-associated and free-living communities ordinated by river system, a pattern that was apparent even after rare sequences or those affiliated with Cyanobacteria were removed from the analyses. Ordination of samples by river system correlated with environmental characteristics of each river, such as nutrient status and turbidity. Communities in the Upper Mississippi and the Missouri and in the Ohio and the Tennessee, pairs of rivers that join each other, contained similar taxa in terms of presence-absence data but differed in the proportional abundance of major lineages. The most common sequence types detected in particle-associated communities were picocyanobacteria in the Synechococcus/Prochlorococcus/Cyanobium (Syn/Pro) clade, while free-living communities also contained a high proportion of LD12 (SAR11/Pelagibacter)-like Alphaproteobacteria. This research shows that while different tributaries of large river systems such as the Mississippi River harbor distinct bacterioplankton communities, there is also microhabitat variation such as that between free-living and particle-associated assemblages. PMID:25217018

  7. Maximum growth rates and possible life strategies of different bacterioplankton groups in relation to phosphorus availability in a freshwater reservoir

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Horňák, Karel; Jezbera, Jan; Nedoma, Jiří; Vrba, Jaroslav; Straškrábová, Viera; Macek, Miroslav; Dolan, J. R.; Hahn, M.W.

    2006-01-01

    Roč. 8, č. 9 (2006), s. 1613-1624. ISSN 1462-2912 R&D Projects: GA ČR(CZ) GA206/05/0007; GA AV ČR(CZ) 1QS600170504 Grant ostatní: MŠM(CZ) 60076658/01 Institutional research plan: CEZ:AV0Z60170517 Keywords : bacterioplankton community composition * growth of bacteria and flagellates * phosphorus availability * reservoir * top-down and bottom-up control Subject RIV: EE - Microbiology, Virology Impact factor: 4.630, year: 2006

  8. The diversity of the Limnohabitans genus, an important group of freshwater bacterioplankton, by characterization of 35 isolated strains

    Czech Academy of Sciences Publication Activity Database

    Kasalický, Vojtěch; Jezbera, Jan; Hahn, M.W.; Šimek, Karel

    2013-01-01

    Roč. 8, č. 3 (2013), e58209. E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA206/08/0015; GA ČR(CZ) GAP504/10/0566; GA MŠk(CZ) MEB060702; GA MŠk(CZ) MEB060901 Institutional research plan: CEZ:AV0Z60170517 Institutional support: RVO:60077344 Keywords : bacterial microdiversity * aquatic * Limnohabitans * freshwater * bacterioplankton Subject RIV: EE - Microbiology, Virology Impact factor: 3.534, year: 2013

  9. Influence of salinity on bacterioplankton communities from the Brazilian rain forest to the coastal Atlantic Ocean.

    Directory of Open Access Journals (Sweden)

    Cynthia B Silveira

    parameters. Furthermore, this paper reveals for the first time the pristine bacterioplankton communities in a tropical island at the South Atlantic Ocean.

  10. Bacterioplankton Biogeography of the Atlantic Ocean: A Case Study of the Distance-Decay Relationship

    Science.gov (United States)

    Milici, Mathias; Tomasch, Jürgen; Wos-Oxley, Melissa L.; Decelle, Johan; Jáuregui, Ruy; Wang, Hui; Deng, Zhi-Luo; Plumeier, Iris; Giebel, Helge-Ansgar; Badewien, Thomas H.; Wurst, Mascha; Pieper, Dietmar H.; Simon, Meinhard; Wagner-Döbler, Irene

    2016-01-01

    In order to determine the influence of geographical distance, depth, and Longhurstian province on bacterial community composition and compare it with the composition of photosynthetic micro-eukaryote communities, 382 samples from a depth-resolved latitudinal transect (51°S–47°N) from the epipelagic zone of the Atlantic ocean were analyzed by Illumina amplicon sequencing. In the upper 100 m of the ocean, community similarity decreased toward the equator for 6000 km, but subsequently increased again, reaching similarity values of 40–60% for samples that were separated by ~12,000 km, resulting in a U-shaped distance-decay curve. We conclude that adaptation to local conditions can override the linear distance-decay relationship in the upper epipelagial of the Atlantic Ocean which is apparently not restrained by barriers to dispersal, since the same taxa were shared between the most distant communities. The six Longhurstian provinces covered by the transect were comprised of distinct microbial communities; ~30% of variation in community composition could be explained by province. Bacterial communities belonging to the deeper layer of the epipelagic zone (140–200 m) lacked a distance-decay relationship altogether and showed little provincialism. Interestingly, those biogeographical patterns were consistently found for bacteria from three different size fractions of the plankton with different taxonomic composition, indicating conserved underlying mechanisms. Analysis of the chloroplast 16S rRNA gene sequences revealed that phytoplankton composition was strongly correlated with both free-living and particle associated bacterial community composition (R between 0.51 and 0.62, p < 0.002). The data show that biogeographical patterns commonly found in macroecology do not hold for marine bacterioplankton, most likely because dispersal and evolution occur at drastically different rates in bacteria. PMID:27199923

  11. Alkane Hydroxylase Gene (alkB Phylotype Composition and Diversity in Northern Gulf of Mexico Bacterioplankton

    Directory of Open Access Journals (Sweden)

    Conor Blake Smith

    2013-12-01

    Full Text Available Natural and anthropogenic activities introduce alkanes into marine systems where they are degraded by alkane hydroxylases expressed by phylogenetically diverse bacteria. Partial sequences for alkB, one of the structural genes of alkane hydroxylase, have been used to assess the composition of alkane-degrading communities, and to determine their responses to hydrocarbon inputs. We present here the first spatially extensive analysis of alkB in bacterioplankton of the northern Gulf of Mexico (nGoM, a region that experiences numerous hydrocarbon inputs. We have analyzed 401 partial alkB gene sequences amplified from genomic extracts collected during March 2010 from 17 water column samples that included surface waters and bathypelagic depths. Previous analyses of 16S rRNA gene sequences for these and related samples have shown that nGoM bacterial community composition and structure stratify strongly with depth, with distinctly different communities above and below 100 m. Although we hypothesized that alkB gene sequences would exhibit a similar pattern, PCA analyses of operational protein units (OPU indicated that community composition did not vary consistently with depth or other major physical-chemical variables. We observed 22 distinct OPUs, one of which was ubiquitous and accounted for 57% of all sequences. This OPU clustered with alkB sequences from known hydrocarbon oxidizers (e.g., Alcanivorax and Marinobacter. Some OPUs could not be associated with known alkane degraders, however, and perhaps represent novel hydrocarbon-oxidizing populations or genes. These results indicate that the capacity for alkane hydrolysis occurs widely in the nGoM, but that alkane degrader diversity varies substantially among sites and responds differently than bulk communities to physical-chemical variables.

  12. Phytoplankton relationship with bacterioplankton, dissolved carbohydrates and water characteristics in a subtropical coastal lagoon

    Directory of Open Access Journals (Sweden)

    Pablo S. Guimarães

    2013-10-01

    Full Text Available Release of carbohydrates by phytoplankton enhances microbial diversity, promoting associations between algae and heterotrophic organisms. Thus, this work aimed to characterise the dissolved carbohydrates at a Brazilian subtropical coastal lagoon (Merin lagoon, in addition to determining their relationships with environmental parameters and phyto/bacterioplankton communities over one year. We analysed the relationships among physical, chemical and biological parameters by a principal component analysis (PCA after normalisation of data as z scores. Chlorophyceae showed the highest richness, although Bacillariophyceae and Cyanophyceae showed the highest densities. These classes are essentially represented by centric diatoms (Aulacoseira cf. muzzanensis and filamentous cyanobacteria (Planktolyngbya limnetica and Planktolyngbya cf. contorta. Merin lagoon showed a strong seasonal behaviour for most of parameters and phytoplanktonic density was mainly correlated with temperature, specific conductance, phosphate and total bright sunshine duration. Only combined dissolved carbohydrates (CDCHOs were found and their main components were glucose (31.6%, mannose/xylose (20.6%, ribose (13.9%, arabinose (8.9% and galacturonic acid (8.1%. The CDCHO amounts were higher in November, March-April and September and the December/January and July/August periods showed lower ones. Ribose was first detected only in the warm months and it gradually decreased with bacterial density. The carbohydrate concentration was coupled to phytoplanktonic density, except in December and January, when the bacterial density was increased. These results supported the significance of dissolved carbohydrates in associations with algae and bacteria in the freshwater planktonic environment. Our data reinforced the influence of phytoplankton community on the natural dissolved carbohydrate pool, besides the significance of such carbon source on the bacterial community dynamic.

  13. Bacterioplankton features and its relations with doc characteristics and other limnological variables in Paraná river floodplain environments (PR/MS-Brazil).

    Science.gov (United States)

    Teixeira, Mariana Carolina; Santana, Natália Fernanda; de Azevedo, Júlio César Rodrigues; Pagioro, Thomaz Aurélio

    2011-07-01

    Since the introduction of the Microbial Loop concept, many studies aimed to explain the role of bacterioplankton and dissolved organic carbon (DOC) in aquatic ecosystems. Paraná River floodplain system is a very complex environment where these subjects were little explored. The aim of this work was to characterize bacterial community in terms of density, biomass and biovolume in some water bodies of this floodplain and to verify its temporal variation and its relation with some limnological variables, including some indicators of DOC quality, obtained through Ultraviolet-visible (UV-VIS) and fluorescence spectroscopic analysis. Bacterial density, biomass and biovolume are similar to those from other freshwater environments and both density and biomass were higher in the period with less rain. The limnological and spectroscopic features that showed any relation with bacterioplankton were the concentrations of N-NH4 and P-PO4, water transparency, and some indicators of DOC quality and origin. The analysis of these relations showed a possible competition between bacterioplankton and phytoplankton for inorganic nutrients and that the DOC used by bacterioplankton is labile and probably from aquatic macrophytes. PMID:24031705

  14. Bacterioplankton features and its relations with doc characteristics and other limnological variables in Paraná river floodplain environments (PR/MS-Brazil

    Directory of Open Access Journals (Sweden)

    Mariana Carolina Teixeira

    2011-09-01

    Full Text Available Since the introduction of the Microbial Loop concept, many studies aimed to explain the role of bacterioplankton and dissolved organic carbon (DOC in aquatic ecosystems. Paraná River floodplain system is a very complex environment where these subjects were little explored. The aim of this work was to characterize bacterial community in terms of density, biomass and biovolume in some water bodies of this floodplain and to verify its temporal variation and its relation with some limnological variables, including some indicators of DOC quality, obtained through Ultraviolet-visible (UV-VIS and fluorescence spectroscopic analysis. Bacterial density, biomass and biovolume are similar to those from other freshwater environments and both density and biomass were higher in the period with less rain. The limnological and spectroscopic features that showed any relation with bacterioplankton were the concentrations of N-NH4 and P-PO4, water transparency, and some indicators of DOC quality and origin. The analysis of these relations showed a possible competition between bacterioplankton and phytoplankton for inorganic nutrients and that the DOC used by bacterioplankton is labile and probably from aquatic macrophytes.

  15. Seasonality in molecular and cytometric diversity of marine bacterioplankton: the reshuffling of bacterial taxa by vertical mixing

    KAUST Repository

    García, Francisca C.

    2015-07-17

    The ’cytometric diversity’ of phytoplankton communities has been studied based on single-cell properties, but the applicability of this method to characterize bacterioplankton has been unexplored. Here, we analysed seasonal changes in cytometric diversity of marine bacterioplankton along a decadal time-series at three coastal stations in the Southern Bay of Biscay. Shannon-Weaver diversity estimates and Bray-Curtis similarities obtained by cytometric and molecular (16S rRNA tag sequencing) methods were significantly correlated in samples from a 3.5-year monthly time-series. Both methods showed a consistent cyclical pattern in the diversity of surface bacterial communities with maximal values in winter. The analysis of the highly resolved flow cytometry time-series across the vertical profile showed that water column mixing was a key factor explaining the seasonal changes in bacterial composition and the winter increase in bacterial diversity in coastal surface waters. Due to its low cost and short processing time as compared to genetic methods, the cytometric diversity approach represents a useful complementary tool in the macroecology of aquatic microbes.

  16. Bacterioplankton communities of Crater Lake, OR: Dynamic changes with euphotic zone food web structure and stable deep water populations

    Science.gov (United States)

    Urbach, E.; Vergin, K.L.; Larson, G.L.; Giovannoni, S.J.

    2007-01-01

    The distribution of bacterial and archaeal species in Crater Lake plankton varies dramatically over depth and with time, as assessed by hybridization of group-specific oligonucleotides to RNA extracted from lakewater. Nonmetric, multidimensional scaling (MDS) analysis of relative bacterial phylotype densities revealed complex relationships among assemblages sampled from depth profiles in July, August and September of 1997 through 1999. CL500-11 green nonsulfur bacteria (Phylum Chloroflexi) and marine Group I crenarchaeota are consistently dominant groups in the oxygenated deep waters at 300 and 500 m. Other phylotypes found in the deep waters are similar to surface and mid-depth populations and vary with time. Euphotic zone assemblages are dominated either by ??-proteobacteria or CL120-10 verrucomicrobia, and ACK4 actinomycetes. MDS analyses of euphotic zone populations in relation to environmental variables and phytoplankton and zooplankton population structures reveal apparent links between Daphnia pulicaria zooplankton population densities and microbial community structure. These patterns may reflect food web interactions that link kokanee salmon population densities to community structure of the bacterioplankton, via fish predation on Daphnia with cascading consequences to Daphnia bacterivory and predation on bacterivorous protists. These results demonstrate a stable bottom-water microbial community. They also extend previous observations of food web-driven changes in euphotic zone bacterioplankton community structure to an oligotrophic setting. ?? 2007 Springer Science+Business Media B.V.

  17. Community differentiation and population enrichment of Sargasso Sea bacterioplankton in the euphotic zone of a mesoscale mode-water eddy.

    Science.gov (United States)

    Nelson, Craig E; Carlson, Craig A; Ewart, Courtney S; Halewood, Elisa R

    2014-03-01

    Eddies are mesoscale oceanographic features (∼ 200 km diameter) that can cause transient blooms of phytoplankton by shifting density isoclines in relation to light and nutrient resources. To better understand how bacterioplankton respond to eddies, we examined depth-resolved distributions of bacterial populations across an anticyclonic mode-water eddy in the Sargasso Sea. Previous work on this eddy has documented elevated phytoplankton productivity and diatom abundance within the eddy centre with coincident bacterial productivity and biomass maxima. We illustrate bacterial community shifts within the eddy centre, differentiating populations uplifted along isopycnals from those enriched or depleted at horizons of enhanced bacterial and primary productivity. Phylotypes belonging to the Roseobacter, OCS116 and marine Actinobacteria clades were enriched in the eddy core and were highly correlated with pigment-based indicators of diatom abundance, supporting developing hypotheses that members of these clades associate with phytoplankton blooms. Typical mesopelagic clades (SAR202, SAR324, SAR406 and SAR11 IIb) were uplifted within the eddy centre, increasing bacterial diversity in the lower euphotic zone. Typical surface oligotrophic clades (SAR116, OM75, Prochlorococcus and SAR11 Ia) were relatively depleted in the eddy centre. The biogeochemical context of a bloom-inducing eddy provides insight into the ecology of the diverse uncultured bacterioplankton dominating the oligotrophic oceans. PMID:24589288

  18. [Bacterioplankton index of biotic integrity (BP-IBI): an approach for assessing river ecosystem health in Dianchi watershed].

    Science.gov (United States)

    Huang, Yi; Shu, Zhong-Ya

    2013-08-01

    The index of biotic integrity (IBI) has been widely applied to the health assessment of river ecosystems. However, the currently available IBI methods are lack of decomposer-based assessment. Based on the T-RFLP result of bacterioplankton, we developed the bacterioplankton index of biotic integrity (BP-IBI) after the screening of major environmental factors and candidate metrics to assess the health of the inflow rivers in Dianchi Watershed. The evaluation result indicated that the eco-health conditions of 11 reference sites were either level I (8 sites) or level II (3 sites), while the 27 damaged sites were level I (4 sites), level II (14 sites), level III (7 sites), and level IV (2 sites), and there was no level V site. Compared with the other IBI methods and the integrated pollution index, BP-IBI showed better effect in reflecting the influence of the key environmental factors, the land use types and the upstream water types in river ecosystems. Therefore, BP-IBI is a good method to characterize the health status of river ecosystems. PMID:24191542

  19. In vitro study of possible microbial indicators for drowning: Salinity and types of bacterioplankton proliferating in blood.

    Science.gov (United States)

    Kakizaki, Eiji; Kozawa, Shuji; Matsuda, Hirokazu; Muraoka, Eri; Uchiyama, Taketo; Sakai, Masahiro; Yukawa, Nobuhiro

    2011-01-30

    Numbers and types of bacterioplankton proliferating in blood samples mixed with water of various salinity levels were examined to determine the characteristics of species associated with salinity. Water samples (total n=88) were collected from the midstream of two rivers (freshwater; n=10; salinity rivers, n=28, salinity 2.4-3.3%), and from the coast (areas of marine water; n=10; salinity 3.3-3.5%). Freshwater bacteria were identified in 41 of 42 blood samples mixed with water at ≤1.3% salinity, and the genus Aeromonas, which is universally distributed in freshwater environments, was predominant. Marine bacteria were identified in all of 46 blood samples mixed with water at ≥1.8% salinity, and most comprised the genera Vibrio and Photobacterium that are universally distributed in seawater environments. Aeromonas was undetectable in all blood samples mixed with brackish or sea water at ≥1.8% salinity although they are detectable even in seawater environments. Thus, the present results showed that bacterioplankton capable of proliferating in human blood reflects the salinity of water. PMID:20554407

  20. Temporal variation in the specific growth rate of bacterioplankton in the River Cauvery and its four down stream tributaries in Karnataka State, India.

    Science.gov (United States)

    Tondoti Sathyanarayana Rao, Harsha; Yamakanamardi, Sadanand Mallappa; Mallaiah, Mahadeveswamy

    2009-07-01

    The temporal variation in the Specific Growth Rate (SGR) of natural population of heterotrophic bacterioplankton of the river Cauvery and its four down stream tributaries in Karnataka State was monitored over a period of two years from February 2000 to January 2002. The SGR was calculated by taking into account only the abundance of bacterioplankton at the beginning (0 h) and at the end (48 h) incubation period, at room or river temperature. The mean SGR was less and significantly different in the surface waters of river Kapila, Shimsha, Suvarnavathy and Arkavathy. But it was more and significantly different in river Cauvery when compared to other tributaries. This suggests that the river Cauvery was more favorable habitat for SGR of bacterioplankton than the other four watercourses studied. Investigation of interrelationship between SGR and other bacterial variables showed presence of only one correlation with direct counts of particle bound bacteria in river Arkavathy. Further, the relationship between SGR of bacterioplankton and other environmental variables showed the presence of six correlations in river Shimsha, five in river Suvarnavathy, three in river Cauvery, and two each in river Kapila and river Arkavathy. Negative SGR were recorded on thirteen occasions in river Cauvery followed by eleven in river Shimsha, nine in river Suvarnavathy, seven in river Arkavathy and five in river Kapila, out of fifty SGR determinations. This negative SGR were a result of decrease in the observed bacterial cell counts after 48 h incubation from that of 0 h count. The probable reason for such negative growth rate and dependency of SGR of bacterioplankton and environmental variables has been discussed. PMID:18600464

  1. Freshwater bacterioplankton cultured from liver, kidney and lungs of a decomposed cadaver retrieved from a sandy seashore: possibility of drowning in a river and then floating out to sea.

    Science.gov (United States)

    Kakizaki, Eiji; Kozawa, Shuji; Matsuda, Hirokazu; Muraoka, Eri; Uchiyama, Taketo; Sakai, Masahiro; Yukawa, Nobuhiro

    2010-07-01

    A decomposed female body with an open abdomen and pleural cavity washed up on a beach after a powerful typhoon. Autopsy findings could not determine the cause of death because of leaching and putrefaction. Numbers and types of diatoms in organs overall, suggested the aspiration of fresh or brackish water with low salinity. However, this could not be confirmed because of contamination via the open cavities. We simultaneously investigated the presence of bacterioplankton in liver, kidney and lung homogenates using a modification of our reported bacteriological method. The freshwater bacterioplankton Plesiomonas shigelloides was identified in each of these organs, but marine bacterioplankton were undetectable despite the circumstances under which the body was discovered. The presence of freshwater bacterioplankton reinforced the results of the diatom test, and we concluded that this victim had died of drowning in fresh or brackish water with low salinity. PMID:20447853

  2. The study of bacterioplankton dynamics in the Berlengas Archipelago (West coast of Portugal by applying the HJ-biplot method

    Directory of Open Access Journals (Sweden)

    Susana Mendes

    2009-01-01

    Full Text Available The relationship between bacterioplankton and environmental forcing in the Berlengas Archipelago (Western Coast of Portugal were studied between February 2006 and February 2007 in two sampling stations: Berlenga and Canal, using an HJ-biplot. The HJ-biplot showed a simultaneous display of the three main metabolic groups of bacteria involved in carbon cycling (aerobic heterotrophic bacteria, sulphate-reducing bacteria and nitrate-reducing bacteria and environmental parameters, in low dimensions. Our results indicated thatbacterial dynamics are mainly affected by temporal gradients (seasonal gradients with a clear winter versus summer opposition, and less by the spatial structure (Berlenga and Canal. The yearly variation in the abundance of aerobic heterotrophic bacteria were positively correlated with those in chlorophyll a concentration, whereas ammonium concentration and temperature decreased with increasing phosphates and nitrites concentration. The relationship between aerobic heterotrophic bacteria, chlorophyll a and ammonium reveals that phytoplankton is an important source of organic substrates for bacteria.

  3. Effects of decreased resource availability, protozoan grazing and viral impact on a structure of bacterioplankton assemblage in a canyon-shaped reservoir

    Czech Academy of Sciences Publication Activity Database

    Horňák, Karel; Mašín, Michal; Jezbera, Jan; Bettarel, Y.; Nedoma, Jiří; Sime-Ngando, T.; Šimek, Karel

    2005-01-01

    Roč. 52, č. 3 (2005), s. 315-327. ISSN 0168-6496 R&D Projects: GA ČR(CZ) GA206/02/0003 Grant ostatní: PICS(FR) project 1111 Institutional research plan: CEZ:AV0Z60170517 Keywords : bacterioplankton * protozoan grazing * viral lysis Subject RIV: EH - Ecology, Behaviour Impact factor: 2.787, year: 2005

  4. Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study

    OpenAIRE

    J. Piontek; C. Borchard; Sperling, M.; K. G. Schulz; Riebesell, U.; Engel, A.

    2013-01-01

    The effect of elevated seawater carbon dioxide (CO2) on the activity of a natural bacterioplankton community in an Arctic fjord system was investigated by a mesocosm perturbation study in the frame of the European Project on Ocean Acidification (EPOCA). A pCO2 range of 175–1085 μatm was set up in nine mesocosms deployed in the Kongsfjorden (Svalbard). The activity of natural extracellular enzyme assemblages increased in response to acidification. Rates of β-glucosidase ...

  5. Phylogenetic compositions of bacterioplankton from two California estuaries compared by denaturing gradient gel electrophoresis of 16S rDNA fragments.

    OpenAIRE

    Murray, A. E.; Hollibaugh, J.T.; Orrego, C.

    1996-01-01

    The phylogenetic compositions of bacterioplankton assemblages from San Francisco Bay and Tomales Bay, Calif., differed substantially when analyzed by PCR-denaturing gradient gel electrophoresis; these differences are consistent with the results of previous studies demonstrating differences in their metabolic capabilities. PCR-denaturing gradient gel electrophoresis analysis of complex microbial assemblages was sensitive and reliable, and the results were reproducible as shown by experiments w...

  6. Contrasting patterns of free-living bacterioplankton diversity in macrophyte-dominated versus phytoplankton blooming regimes in Dianchi Lake, a shallow lake in China

    Science.gov (United States)

    Wang, Yujing; Li, Huabing; Xing, Peng; Wu, Qinglong

    2016-04-01

    Freshwater shallow lakes typically exhibit two alternative stable states under certain nutrient loadings: macrophyte-dominated and phytoplankton-dominated water regimes. An ecosystem regime shift from macrophytes to phytoplankton blooming typically reduces the number of species of invertebrates and fishes and results in the homogenization of communities in freshwater lakes. We investigated how microbial biodiversity has responded to a shift of the ecosystem regime in Dianchi Lake, which was previously fully covered with submerged macrophytes but currently harbors both ecological states. We observed marked divergence in the diversity and community composition of bacterioplankton between the two regimes. Although species richness, estimated as the number of operational taxonomic units and phylogenetic diversity (PD), was higher in the phytoplankton dominated ecosystem after this shift, the dissimilarity of bacterioplankton community across space decreased. This decrease in beta diversity was accompanied by loss of planktonic bacteria unique to the macrophyte-dominated ecosystem. Mantel tests between bacterioplankton community distances and Euclidian distance of environmental parameters indicated that this reduced bacterial community diff erentiation primarily reflected the loss of environmental niches, particularly in the macrophyte regime. The loss of this small-scale heterogeneity in bacterial communities should be considered when assessing long-term biodiversity changes in response to ecosystem regime conversions in freshwater lakes.

  7. Maximum growth rates and possible life strategies of different bacterioplankton groups in relation to phosphorus availability in a freshwater reservoir.

    Science.gov (United States)

    Simek, Karel; Hornák, Karel; Jezbera, Jan; Nedoma, Jirí; Vrba, Jaroslav; Straskrábová, Viera; Macek, Miroslav; Dolan, John R; Hahn, Martin W

    2006-09-01

    We investigated net growth rates of distinct bacterioplankton groups and heterotrophic nanoflagellate (HNF) communities in relation to phosphorus availability by analysing eight in situ manipulation experiments, conducted between 1997 and 2003, in the canyon-shaped Rímov reservoir (Czech Republic). Water samples were size-fractionated and incubated in dialysis bags at the sampling site or transplanted into an area of the reservoir, which differed in phosphorus limitation (range of soluble reactive phosphorus concentrations--SRP, 0.7-96 microg l-1). Using five different rRNA-targeted oligonucleotide probes, net growth rates of the probe-defined bacterial groups and HNF assemblages were estimated and related to SRP using Monod kinetics, yielding growth rate constants specific for each bacterial group. We found highly significant differences among their maximum growth rates while insignificant differences were detected in the saturation constants. However, the latter constants represent only tentative estimates mainly due to insufficient sensitivity of the method used at low in situ SRP concentrations. Interestingly, in these same experiments HNF assemblages grew significantly faster than any bacterial group studied except for a small, but abundant cluster of Betaproteobacteria (targeted by the R-BT065 probe). Potential ecological implications of different growth capabilities for possible life strategies of different bacterial phylogenetic lineages are discussed. PMID:16913921

  8. Betaproteobacteria Limnohabitans strains increase fecundity in the crustacean Daphnia magna: symbiotic relationship between major bacterioplankton and zooplankton in freshwater ecosystem.

    Science.gov (United States)

    Peerakietkhajorn, Saranya; Kato, Yasuhiko; Kasalický, Vojtěch; Matsuura, Tomoaki; Watanabe, Hajime

    2016-09-01

    How symbioses between bacteria and aquatic animals influence food webs in freshwater ecosystems is a fundamental question in ecology. We investigated symbiosis between a crustacean zooplankton Daphnia magna and its dominant bacterial symbiont Limnohabitans, an abundant and globally distributed freshwater Betaproteobacteria. Aposymbiotic juvenile Daphnia were prepared and exposed to any of four Limnohabitans sp. - Limnohabitans strains DM1, 2KL-3, 2KL-7 and Limnohabitans planktonicus strain II-D5, all previously found in D. magna digestive tract or culture. Re-infected Daphnia were cultured until they produced the first clutch of juveniles. Limnohabitans strain DM1 and L. planktonicus strain II-D5 successfully re-infected Daphnia through single exposure at the first instar juvenile stage. In contrast to aposymbiotic Daphnia that produced non-viable juveniles, re-infected Daphnia produced viable juveniles and increased fecundity to levels of that of symbiotic Daphnia. Re-infected Daphnia did not increase their number of eggs nor growth rates. Limnohabitans strains 2KL-7 and 2KL-3 could not recover fecundity even in multiple exposures during culture. This study shows the functional evidence demonstrating that a single bacterium Limnohabitans regulates fecundity of the consumer Daphnia through symbiosis. Our results indicated that symbiotic relationship between major bacterioplankton and zooplankton is important for maintaining the population of zooplankton in freshwater ecosystems. PMID:26014379

  9. Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study

    OpenAIRE

    Riebesell, U.; Engel, A.; K. G. Schulz; Sperling, M.; C. Borchard; J. Piontek

    2013-01-01

    The effect of elevated seawater carbon dioxide (CO2) on the activity of a natural bacterioplankton community in an Arctic fjord system was investigated by a mesocosm perturbation study in the frame of the European Project on Ocean Acidification (EPOCA). A pCO2 range of 175–1085 μatm was set up in nine mesocosms deployed in the Kongsfjorden (Svalbard). The activity of natural extracellular enzyme assemblages increased in response to acidification. Rates of β-glucosidase and leucine-aminop...

  10. Spatio-temporal patterns of bacterioplankton production and community composition related to phytoplankton composition and protistan bacterivory in a dam reservoir

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Horňák, Karel; Jezbera, Jan; Nedoma, Jiří; Znachor, Petr; Hejzlar, Josef; Seďa, Jaromír

    2008-01-01

    Roč. 51, č. 3 (2008), s. 249-262. ISSN 0948-3055 R&D Projects: GA ČR(CZ) GA206/08/0015; GA ČR(CZ) GA206/05/0007; GA AV ČR(CZ) 1QS600170504 Institutional research plan: CEZ:AV0Z60170517 Keywords : bacterioplankton composition and production * algal-bacterial relationships * extracellular phytoplankton production * protistan bacterivory * phytoplankton community * reservoir * betaproteobacterial groups Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.190, year: 2008

  11. Links between resources, C metabolism and the major components of bacterioplankton community structure across a range of freshwater ecosystems.

    Science.gov (United States)

    Comte, Jérôme; del Giorgio, Paul A

    2009-07-01

    We explored the patterns in bacterioplankton community metabolism (BCM) and four components of community structure [composition (BCC), metabolic capacities (MC), physiological structure (PS) and single-cell characteristics (SCC)], between lakes, rivers and marshes within a watershed in Québec, to assess the connections that exist between them and with the main resources (organic matter, nutrients). Habitat types were well segregated by both resources and BCM and their corresponding dissimilarity matrices were significantly correlated, suggesting that BCM tracks resource conditions in a consistent manner across ecosystem types. MC also segregated the various habitats and was correlated to BCM but less so to resources, whereas BCC at times resulted in a clear separation of habitats, but was rarely correlated to resources and never to BCM, suggesting a higher degree of ecosystem specificity at this particular level. Finally, there was no clear separation of habitats in terms of PS and SCC, and none covaried with resources or BCM. The habitat patterns based on these different components of structure were rarely correlated to each other, indicating weak deterministic connections between them. MC appears to mediate the link between resources and BCM more directly and consistently across systems; BCC appears to be more influenced by ecosystem-specific factors that weaken its overall connection to both resources and BCM, whereas PS and SCC show no discernible patterns. Our results thus suggest that the bottom-up regulation of BCM by resources is mediated by complex shifts within components of community structure that can be directional, ecosystem-specific or apparently random, which combined nevertheless result in a systematic overall response to resources in terms of C metabolism. PMID:19508562

  12. Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study

    Science.gov (United States)

    Piontek, J.; Borchard, C.; Sperling, M.; Schulz, K. G.; Riebesell, U.; Engel, A.

    2013-01-01

    The effect of elevated seawater carbon dioxide (CO2) on the activity of a natural bacterioplankton community in an Arctic fjord system was investigated by a mesocosm perturbation study in the frame of the European Project on Ocean Acidification (EPOCA). A pCO2 range of 175-1085 μatm was set up in nine mesocosms deployed in the Kongsfjorden (Svalbard). The activity of natural extracellular enzyme assemblages increased in response to acidification. Rates of β-glucosidase and leucine-aminopeptidase increased along the gradient of mesocosm pCO2. A decrease in seawater pH of 0.5 units almost doubled rates of both enzymes. Heterotrophic bacterial activity was closely coupled to phytoplankton productivity in this experiment. The bacterioplankton community responded to rising chlorophyll a concentrations after a lag phase of only a few days with increasing protein production and extracellular enzyme activity. Time-integrated primary production and bacterial protein production were positively correlated, strongly suggesting that higher amounts of phytoplankton-derived organic matter were assimilated by heterotrophic bacteria at increased primary production. Primary production increased under high pCO2 in this study, and it can be suggested that the efficient heterotrophic carbon utilisation had the potential to counteract the enhanced autotrophic CO2 fixation. However, our results also show that beneficial pCO2-related effects on bacterial activity can be mitigated by the top-down control of bacterial abundances in natural microbial communities.

  13. Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study

    Directory of Open Access Journals (Sweden)

    U. Riebesell

    2013-01-01

    Full Text Available The effect of elevated seawater carbon dioxide (CO2 on the activity of a natural bacterioplankton community in an Arctic fjord system was investigated by a mesocosm perturbation study in the frame of the European Project on Ocean Acidification (EPOCA. A pCO2 range of 175–1085 μatm was set up in nine mesocosms deployed in the Kongsfjorden (Svalbard. The activity of natural extracellular enzyme assemblages increased in response to acidification. Rates of β-glucosidase and leucine-aminopeptidase increased along the gradient of mesocosm pCO2. A decrease in seawater pH of 0.5 units almost doubled rates of both enzymes. Heterotrophic bacterial activity was closely coupled to phytoplankton productivity in this experiment. The bacterioplankton community responded to rising chlorophyll a concentrations after a lag phase of only a few days with increasing protein production and extracellular enzyme activity. Time-integrated primary production and bacterial protein production were positively correlated, strongly suggesting that higher amounts of phytoplankton-derived organic matter were assimilated by heterotrophic bacteria at increased primary production. Primary production increased under high pCO2 in this study, and it can be suggested that the efficient heterotrophic carbon utilisation had the potential to counteract the enhanced autotrophic CO2 fixation. However, our results also show that beneficial pCO2-related effects on bacterial activity can be mitigated by the top-down control of bacterial abundances in natural microbial communities.

  14. Effect of elevated CO2 on the dynamics of particle attached and free living bacterioplankton communities in an Arctic fjord

    Science.gov (United States)

    Sperling, M.; Piontek, J.; Gerdts, G.; Wichels, A.; Schunck, H.; Roy, A.-S.; La Roche, J.; Gilbert, J.; Bittner, L.; Romac, S.; Riebesell, U.; Engel, A.

    2012-08-01

    The increase in atmospheric carbon dioxide (CO2) results in acidification of the oceans, expected to lead to the fastest drop in ocean pH in the last 300 million years, if anthropogenic emissions are continued at present rate. Due to higher solubility of gases in cold waters and increased exposure to the atmosphere by decreasing ice cover, the Arctic Ocean will be among the areas most strongly affected by ocean acidification. Yet, the response of the plankton community of high latitudes to ocean acidification has not been studied so far. This work is part of the Arctic campaign of the European Project on Ocean Acidification (EPOCA) in 2010, employing 9 in situ mesocosms of about 45 000 l each to simulate ocean acidification in Kongsfjorden, Svalbard (78°56.2' N 11°53.6' E). In the present study, we investigated effects of elevated CO2 on the composition and richness of particle attached (PA; >3 μm) and free living (FL; 0.2 μm) bacterial communities by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms and the surrounding fjord, ranging from 185 to 1050 initial μatm pCO2. ARISA was able to resolve about 20-30 bacterial band-classes per sample and allowed for a detailed investigation of the explicit richness. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom (phase 3 of the experiment), number of ARISA-band classes in the PA-community were reduced at low and medium CO2 (∼180-600 μatm) by about 25%, while it was more or less stable at high CO2 (∼ 650-800 μatm). We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA-bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production was enhanced in

  15. Effect of elevated CO2 on the dynamics of particle attached and free living bacterioplankton communities in an Arctic fjord

    Directory of Open Access Journals (Sweden)

    S. Romac

    2012-08-01

    Full Text Available The increase in atmospheric carbon dioxide (CO2 results in acidification of the oceans, expected to lead to the fastest drop in ocean pH in the last 300 million years, if anthropogenic emissions are continued at present rate. Due to higher solubility of gases in cold waters and increased exposure to the atmosphere by decreasing ice cover, the Arctic Ocean will be among the areas most strongly affected by ocean acidification. Yet, the response of the plankton community of high latitudes to ocean acidification has not been studied so far. This work is part of the Arctic campaign of the European Project on Ocean Acidification (EPOCA in 2010, employing 9 in situ mesocosms of about 45 000 l each to simulate ocean acidification in Kongsfjorden, Svalbard (78°56.2' N 11°53.6' E. In the present study, we investigated effects of elevated CO2 on the composition and richness of particle attached (PA; >3 μm and free living (FL; 0.2 μm bacterial communities by Automated Ribosomal Intergenic Spacer Analysis (ARISA in 6 of the mesocosms and the surrounding fjord, ranging from 185 to 1050 initial μatm pCO2. ARISA was able to resolve about 20–30 bacterial band-classes per sample and allowed for a detailed investigation of the explicit richness. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom (phase 3 of the experiment, number of ARISA-band classes in the PA-community were reduced at low and medium CO2 (∼180–600 μatm by about 25%, while it was more or less stable at high CO2 (∼ 650–800 μatm. We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA-bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production

  16. Bacterioplankton dynamics along the gradient from highly eutrophic Pearl River Estuary to oligotrophic northern South China Sea in wet season: implication for anthropogenic inputs.

    Science.gov (United States)

    Zhou, Weihua; Long, Aimin; Jiang, Tao; Chen, Shaoyong; Huang, Liangmin; Huang, Hui; Cai, Chuanghua; Yan, Yan

    2011-04-01

    Bacterioplankton abundance (BA) and biomass (BB) from the eutrophic Pearl River Estuary (PRE) to the oligotrophic northern South China Sea (NSCS) were studied in the wet season. BA was significantly higher (p 100 μM and PO₄ > 1 μM) resulted in high chl a and BB, whereas nutrient-depleted offshore waters (DIN 26 °C) was not the controlling factor of BA. BB was significantly correlated with chl a biomass both in PRE and NSCS. The bacteria to phytoplankton biomass (BB/PB) ratio increased clearly along the gradient from near-shore PRE (0.15) to offshore CSNP (0.93) and deep OP (2.75), indicating the important role of small cells in the open ocean compared to estuarine and coastal zones. PMID:21316714

  17. Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study

    Directory of Open Access Journals (Sweden)

    U. Riebesell

    2012-08-01

    Full Text Available The effect of elevated seawater carbon dioxide (CO2 on the activity of a natural bacterioplankton community in an Arctic fjord system was investigated by a mesocosm perturbation study in the frame of the European Project on Ocean Acidification (EPOCA. A pCO2 range of 175–1085 μatm was set up in nine mesocosms deployed in the Kongsfjorden (Svalbard. The bacterioplankton communities responded to rising chlorophyll a concentrations after a lag phase of only a few days with increasing protein production and extracellular enzyme activity and revealed a close coupling of heterotrophic bacterial activity to phytoplankton productivity in this experiment. The natural extracellular enzyme assemblages showed increased activity in response to moderate acidification. A decrease in seawater pH of 0.5 units roughly doubled rates of β-glucosidase and leucine-aminopeptidase. Activities of extracellular enzymes in the mesocosms were directly related to both seawater pH and primary production. Also primary production and bacterial protein production in the mesocosms at different pCO2 were positively correlated. Therefore, it can be suggested that the efficient heterotrophic carbon utilization in this Arctic microbial food web had the potential to counteract increased phytoplankton production that was achieved under elevated pCO2 in this study. However, our results also show that the transfer of beneficial pCO2-related effects on the cellular bacterial metabolism to the scale of community activity and organic matter degradation can be mitigated by the top-down control of bacterial abundances in natural microbial communities.

  18. 对虾养殖围隔生态系统浮游细菌的呼吸与生产%Respiration and production of bacterioplankton in shrimp cultural enclosure ecosystems

    Institute of Scientific and Technical Information of China (English)

    刘国才; 李德尚; 董双林

    2003-01-01

    The study on the respiration and production of bacterioplankton in five shrimp cultural enclosure ecosystems showed that the production and respiration fluctuated from 90 to 909 and 248 to 1785 μgC· L-1. d-l, respec-tively. There existed a significant positive relationship between production and respiration. The daily P/B ratio of bacterioplancton averaged 0.93 d-l, and its production efficiency averaged 0.34.

  19. Photo-degradation effect on dissolved organic carbon availability to bacterioplankton in a lake in the upper Paraná river floodplain - doi: 10.4025/actascibiolsci.v35i1.11054

    Directory of Open Access Journals (Sweden)

    Júlio César Rodrigues de Azevedo

    2012-12-01

    Full Text Available Dissolved organic carbon (DOC is nowadays recognized as the main substrate and source of energy for aquatic microbial community. The great part of available organic carbon for bacterioplankton might be formed after photolytic degradation of humic material, which constitutes the major part of DOC in almost all natural waters. The effects of DOC photo-degradation were evaluated, as was its utilization by bacterioplankton, through a two-step experiment, one involving photo-degradation of DOC and the other bacterial growth on the photo-degraded substrate. Photo-degradation was responsible for the consumption of 19% of DOC, reduced SUVA254, an increase in the E2/E3 and E3/E4 ratios, in addition to modifications in the fluorescence spectra that indicated a rise in the labile fraction of DOC. However, these alterations on DOC were not reflected in differences in bacterioplankton growth, as shown by the fact that there were no significant differences in density, biomass, bacterial production, bacterial respiration and bacterial growth efficiency between treatment and control.  

  20. Seasonal and spatial distribution of Bacterioplankton in a fluvial-lagunar system of a tropical region: density, biomass, cellular volume and morphologic variation

    Directory of Open Access Journals (Sweden)

    Magnólia Fernandes Florêncio de Araújo

    2008-02-01

    Full Text Available The temporal and spatial fluctuations of Bacterioplankton in a fluvial-lagunar system of a tropical region (Pitimbu River and Jiqui Lake, RN were studied during the dry and the rainy periods. The bacterial abundance varied from 2.67 to 5.1 Cells10(7mL-1 and did not show a typical temporal variation, presenting only small oscillations between the rainy and the dry periods. The bacterial biomass varied from 123 µgC L-1 to 269 µgC L-1 in the sampling sites and the average cellular volume varied from 0.12 to 0.54µm³, showing a predominance of the rods. The temperature showed a positive correlation with the cellular volume of the rods (R=0.55; p=0.02 and vibrio (R=0.53; p=0.03. Significant spatial differences of biomass (Mann Whitney: p=0.01 and cellular volume of the morphotypes (Mann Whitney: p=0.003 were found between the sampling sites. The strong positive correlations of the water temperature and oxygen with bacterioplankton showed a probable high bacterial activity in this system.A variação temporal e espacial do bacterioplâncton em um sistema fluvial-lagunar de região tropical foi estudada em períodos seco e chuvoso. As médias da abundância bacteriana variaram de 2,67 a 5,1 x 10(7 e não exibiram uma variação temporal marcante, tendo apresentado apenas pequenas oscilações entre os períodos chuvoso e seco. A biomassa bacteriana variou de 123 µg C L-1 a 269 µg C L-1 entre os locais de coleta e o volume celular médio de 0,12µm³ a 0,54µm³, ocorrendo predominância de bacilos. A temperatura mostrou correlação positiva com o volume celular de bacilos (R=0,55; p=0,02 e de vibriões (R=0,53; p=0,03. Foram encontradas diferenças espaciais significativas de biomassa (Mann Whitney: p=0,01 e volume celular dos morfotipos (Mann Whitney: p= 0,003, entre os locais de coleta. As fortes correlações positivas da temperatura da água e do oxigênio, com o bacterioplâncton, são sugestivas de uma provavelmente elevada atividade

  1. Spatial variability in the abundance and composition of the free-living bacterioplankton community in the pelagic zone of Lake Bourget (France).

    Science.gov (United States)

    Dorigo, Ursula; Fontvieille, Dominique; Humbert, Jean-François

    2006-10-01

    Spatial variations in the abundance and diversity of the free-living bacterioplankton community of a large Alpine lake, Lake Bourget (France), were investigated in the pelagic zone by means of two two-dimensional samplings taken in 2003. Lake-water samples were collected in winter during water mixing, and in early summer during stratification. The population abundance in each sample was determined by flow cytometry. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments from organisms measuring less than 2 mum was used to assess eubacterioplankton community composition. In winter, no obvious differences were observed in either the abundance or the diversity of the bacterial community, on either the horizontal or the vertical scales. The only influence detected was that of river water input, but this was at a very minor scale relative to the surface area of the lake. In early summer, changes were found in the community composition on the vertical scale related to the thermal stratification of the water column. There were also marked differences on the horizontal scale at 15 m depth due to internal waves. The implications of these findings for sampling strategies are very important from the perspective of comparative studies of free-living bacterial community diversity and functioning in large and deep lakes. PMID:16958912

  2. Bacterial activity and bacterioplankton diversity in the eutrophic River Warnow--direct measurement of bacterial growth efficiency and its effect on carbon utilization.

    Science.gov (United States)

    Warkentin, Mareike; Freese, Heike M; Schumann, Rhena

    2011-01-01

    The influence of bacterial activity and diversity on bacterial growth efficiency was investigated in a flatland river. Eutrophic River Warnow drains predominantly agricultural land and is heavily loaded with nutrients, dissolved and particulate organic matter (DOM and POM), especially humic substances. Although the water column bacterial community consists of many inactive or damaged cells, bacterioplankton sustained a high bacterial secondary production of 0.2-14.5 μg C L(-1) h(-1) and a high DNA synthesis (thymidine uptake) of 6.1-15.5 μg C L(-1) h(-1). The direct and short-term measurement of bacterial respiration (by optodes) revealed high respiration rates especially in summer leading to directly estimated bacterial growth efficiencies (BGE) of 2-28%. These values are compared to calculations based only on bacterial production, which considerably overestimated BGEs. From all these data, River Warnow can be characterized as a strongly remineralizing system. River Warnow was dominated among others by Cytophaga/Flavobacteria and Actinobacteria which are typical for organic rich waters because of their ability to degrade high molecular weight compounds. However, community composition did not significantly affect BGE. PMID:20676625

  3. Enhanced viral production and virus-mediated mortality of bacterioplankton in a natural iron-fertilized bloom event above the Kerguelen Plateau

    Science.gov (United States)

    Malits, A.; Christaki, U.; Obernosterer, I.; Weinbauer, M. G.

    2014-12-01

    Above the Kerguelen Plateau in the Southern Ocean natural iron fertilization sustains a large phytoplankton bloom over 3 months during austral summer. During the KEOPS1 project (KErguelen Ocean and Plateau compared Study1) we sampled this phytoplankton bloom during its declining phase along with the surrounding high-nutrient-low-chlorophyll (HNLC) waters to study the effect of natural iron fertilization on the role of viruses in the microbial food web. Bacterial and viral abundances were 1.7 and 2.1 times, respectively, higher within the bloom than in HNLC waters. Viral production and virus-mediated mortality of bacterioplankton were 4.1 and 4.9 times, respectively, higher in the bloom, while the fraction of infected cells (FIC) and the fraction of lysogenic cells (FLC) showed no significant differences between environments. The present study suggests viruses to be more important for bacterial mortality within the bloom and dominate over grazing of heterotrophic nanoflagellates (HNFs) during the late bloom phase. As a consequence, at least at a late bloom stage, viral lysis shunts part of the photosynthetically fixed carbon in iron-fertilized regions into the dissolved organic matter (DOM) pool with potentially less particulate organic carbon transferred to larger members of the food web or exported.

  4. Enhanced viral production and virus-mediated mortality of bacterioplankton in a natural iron-fertilized bloom event above the Kerguelen Plateau

    Directory of Open Access Journals (Sweden)

    A. Malits

    2014-07-01

    Full Text Available Above the Kerguelen Plateau in the Southern Ocean natural iron fertilization sustains a large phytoplankton bloom over three months during austral summer. During the KEOPS1 project (KErguelen Ocean and Plateau compared Study1 we sampled this phytoplankton bloom during its declining phase along with the surrounding HNLC waters to study the effect of natural iron fertilization on the role of viruses in the microbial food web. Bacterial and viral abundances were 1.7 and 2.1 times, respectively, higher within the bloom than in HNLC waters. Viral production and virus-mediated mortality of bacterioplankton was 4.1 and 4.9 times, respectively, higher in the bloom, while the fraction of infected cells (FIC and the fraction of lysogenic cells (FLC showed no significant differences between environments. The present study suggests viruses to be more important for bacterial mortality within the bloom and dominate over protozoan grazing during the late bloom phase. As a consequence, at least at a late bloom stage, viral lysis shunts part of the photosynthetically fixed carbon in iron-fertilized regions into the dissolved organic matter (DOM pool with potentially less particulate organic carbon transfered to larger members of the food web or exported.

  5. A new molecular approach to help conclude drowning as a cause of death: simultaneous detection of eight bacterioplankton species using real-time PCR assays with TaqMan probes.

    Science.gov (United States)

    Uchiyama, Taketo; Kakizaki, Eiji; Kozawa, Shuji; Nishida, Sho; Imamura, Nahoko; Yukawa, Nobuhiro

    2012-10-10

    We developed a novel tool for concluding drowning as a cause of death. We designed nine primer pairs to detect representative freshwater or marine bacterioplankton (aquatic bacteria) and then used real-time PCR with TaqMan probes to rapidly and specifically detect them. We previously cultured the genus Aeromonas, which is a representative freshwater bacterial species, in blood samples from 94% of victims who drowned in freshwater and the genera Vibrio and/or Photobacterium that are representative marine bacteria in 88% of victims who drowned in seawater. Based on these results, we simultaneously detected eight species of bacterioplankton (Aeromonas hydrophila, A. salmonicida; Vibrio fischeri, V. harveyi, V. parahaemolyticus; Photobacterium damselae, P. leiognathi, P. phosphoreum) using three sets of triplex real-time PCR assays and TaqMan probes labelled with fluorophores (FAM, NED, Cy5). We assayed 266 specimens (109 blood, 157 tissues) from 43 victims, including 32 who had drowned in rivers, ditches, wells, sea or around estuaries. All lung samples of these 32 victims were TaqMan PCR-positive including the lung periphery into which water does not readily enter postmortem. On the other hand, findings in blood and/or closed organs (kidney or liver) were PCR-positive in 84% of the drowned victims (except for those who drowned in baths) although the conventional test detected diatoms in closed organs in only 44% of the victims. Thus, the results of the PCR assay reinforced those of diatom tests when only a few diatoms were detectable in organs due to the low density of diatoms in the water where they were found. Multiplex TaqMan PCR assays for bacterioplankton were rapid, less laborious and high-throughput as well as sensitive and specific. Therefore, these assays would be useful for routine forensic screening tests to estimate the amount and type of aspirated water. PMID:22682932

  6. The potential impacts of temperature and nutrient levels on freshwater bacterioplankton community structure%温度和营养盐水平对淡水浮游细菌群落结构的潜在影响

    Institute of Scientific and Technical Information of China (English)

    陈祯; 何聃; 任丽娟

    2016-01-01

    To investigate bacterioplankton community composition (BCC)under different temperature and nutrient conditions,18 microcosms combining three temperature scenarios(15 ℃,25 ℃ and 35 ℃,respectively)and two nutrient levels(control and enriched)were established.After three months experiment,water environmental factors, plant biomass(mainly Filamentous green aglea,FGA),bacterioplankton community abundance and composition were studied.Extremely differences of DO,pH,NO-3-N,NO-2-N,FGA biomass were detected under different temperature and nutrient treatments.Both increased temperature (25 ℃ and 35 ℃)and nutrient enrichment stimulated the extensive growth of FGA.The proliferation of FGA had pronounced removal of water nutrients,so that the concentrations of N and P together with the bacterioplankton abundance were similar in nutrient enriched groups.In 1 5 ℃ treatments without nutrient enrichment,the influence of FGA was least and the nutrient concentrations were evidently higher than others,thus BCC there was pronouncedly different from the other treatments.Between 1 5 ℃ treatments without nutrient enrichment and the other treatments,the BCC divergence increased with the increasing differences of temperatures.In summary,we found that temperature and nutrient,as important abiotic factors for freshwater ecosystems,had complex interactions with plants and bacterioplankton community composition in freshwater ecosystem.The elevated temperature and nutrient conditions not only directly shifted BCC,but also indirectly impacted BCC through the growth of FGA.%为研究温度与水体营养条件对淡水浮游细菌群落的影响,进行室内模拟实验,设立了15℃、25℃和35℃三种温度处理和添加营养盐、未添加营养盐两种营养处理,总计6个处理组,每个处理组设计3个重复。实验结束后测定了环境因子、植物生物量、浮游细菌群落丰度和结构。结果发现,不同温度和营养盐条件下,环境中的 DO

  7. Impacts of combined overfishing and oil spills on the plankton trophodynamics of the West Florida shelf over the last half century of 1965-2011: A two-dimensional simulation analysis of biotic state transitions, from a zooplankton- to a bacterioplankton-modulated ecosystem.

    Science.gov (United States)

    Walsh, J. J.; Lenes, J. M.; Darrow, B.; Parks, A.; Weisberg, R. H.

    2016-03-01

    Over 50 years of multiple anthropogenic perturbations, Florida zooplankton stocks of the northeastern Gulf of Mexico declined ten-fold, with increments of mainly dominant toxic dinoflagellate harmful algal blooms (HABs), rather than diatoms, and a shift in loci of nutrient remineralization and oxygen depletion by bacterioplankton, from the sea floor to near surface waters. Yet, lytic bacterial biomass and associated ammonification only increased at most five-fold over the same time period, with consequently little indication of new, expanded "dead zones" of diatom-induced hypoxia. After bacterial lysis of intact cells of these increased HABs, the remaining residues of zooplankton biomass decrements evidently instead exited the water column as malign aerosolized HAB asthma triggers, correlated by co-traveling mercury aerosols, within wind-borne sea sprays. To unravel the causal mechanisms of these inferred decadal food web transitions, a 36-state variable plankton model of algal, bacterial, protozoan, and copepod component communities replicated daily time series of each plankton group's representatives on the West Florida shelf (WFS) during 1965-2011. At the lower phytoplankton trophic levels, 52% of the ungrazed HAB increments, between 1965-1967 and 2001-2002 before recent oil spills, remained in the water column to kill fishes and fuel bacterioplankton. But, another 48% of the WFS primary production then left the ocean's surface as a harbinger of increased public health hazards during continuing sea spray exports of salts, HAB toxins, and Hg poisons. Following the Deepwater Horizon petroleum releases in 2010, little additional change of element partition among the altered importance of WFS food web components of the trophic pyramid then pertained between 2001-2002 and 2010-2011, despite when anomalous upwelled nutrient supplies instead favored retrograde benign, oil-tolerant diatoms over the HABs during 2010. Indeed, by 2011 HABs were back, with biomass

  8. Seasonality of Chesapeake Bay bacterioplankton species.

    Science.gov (United States)

    Heidelberg, J F; Heidelberg, K B; Colwell, R R

    2002-11-01

    Bacteria, gamma-subclass of Proteobacteria, Vibrio-Photobacterium, Vibrio vulnificus, Vibrio cholerae-Vibrio mimicus, and Vibrio cincinnatiensis in water samples collected from the Choptank River in Chesapeake Bay from 15 April to 16 December 1996 were enumerated using a fluorescent oligonucleotide direct-counting (FODC) procedure. FODC results obtained using a Bacteria taxon-specific probe ranged from one-third the number of to the same number as that obtained by the acridine orange direct count (AODC) procedure. The abundance of individual taxa (per liter) ranged from 0.25 x 10(10) to 2.6 x 10(10) Bacteria, 0.32 x 10(8) to 3.1 x 10(8) gamma-Proteobacteria, 0.2 x 10(8) to 2.1 x 10(8) Vibrio-Photobacterium, 0.5 x 10(7) to 10 x 10(7) V. vulnificus, 0.2 x 10(6) to 6 x 10(6) V. cholerae-V. mimicus, and 0.5 x 10(5) to 8 x 10(5) V. cincinnatiensis. The occurrence of all taxa monitored in this study was higher in summer; however, these taxa made up a larger proportion of the Bacteria when the water temperature was low. Large fluctuations in species abundance as well as in percent composition of Vibrio-Photobacterium occurred from week to week, indicating that localized blooms of these taxa occur. The cross-Choptank River transect sample profile of V. vulnificus and V. cholerae-V. mimicus varied significantly in abundance, and trans-Choptank River transect samples revealed a patchy distribution. PMID:12406742

  9. Stream hydrological fragmentation drives bacterioplankton community composition

    OpenAIRE

    Fazi, Stefano; Vazquez, Eusebi; Casamayor, Emilio O; Amalfitano, Stefano; Butturini, Andrea

    2013-01-01

    In Mediterranean intermittent streams, the hydrological fragmentation in summer and the successive water flow re-convergence in autumn allow exploring how local processes shape the microbial community within the same habitat. The objectives of this study were to determine how bacterial community composition responded to hydrological fragmentation in summer, and to evaluate whether the seasonal shifts in community composition predominate over the effects of episodic habitat fragmentation. The ...

  10. Heterotrophic bacterioplankton production in the East China Sea

    Science.gov (United States)

    Xiao, Tian; Wang, Rong; Yue, Hai-Dong

    2001-06-01

    Heterotrophic bacterial production (BP) in the East China Sea was measured using tritiated thymidine incorporation (TTI) method in winter 1997 and in summer 1998. The results showed BP in summer (1998, 3.50-15.70 μgC/(L·h) was higher than that in winter (1997, 0.46-2.62 μgC/(L·h). The high values of BP occurred around the Changjiang River estuary and around Station 410. The results at two anchor stations showed that vertical variation of BP was bottom > middle > surface in winter and middle > bottom > surface in summer. Compared with primary production (BP:PP), the average ratio of BP:PP was 0.17(0.04-0.30) in winter and 0.32(0.21-0.43) in summer. There were high ratios around the Changjiang River estuary in winter and around Station 111 in summer.

  11. The impact of climate change on phytoplankton - bacterioplankton interactions

    OpenAIRE

    Breithaupt, Petra

    2009-01-01

    Global warming has already and is continuing to impact the global oceans. Half of the global primary production is performed by phytoplankton in the oceans and heterotrophic marine bacteria channel a substantial amount of primary organic carbon through the microbial loop. Understanding the influence of climate change on these important processes is therefore essential for an assessment of the vulnerability of the carbon cycle and possible feedbacks. This thesis reports results from investigat...

  12. Bacterioplankton abundance and production in Indian Ocean Regions

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Fernandes, V.; Rodrigues, V.V.; Paul, J.T.; Gauns, M.

    ), warmer sea surface temperatures (SST) (29°–30°C), and weak winds (<7 m s −1 ) stratify the upper 30- to 40-m column [Prasannakumar et al., 2002]. Further, absence of marked upwelling limits nutrient injection into the euphotic layer. The 4.5-layer.... Together with other micro- heterotrophs, these ubiquitous and self-regulating bacterial communities are pivotal for marine ecological dynamics. Thus, information on their abundance, distribution, produc- tion, and their involvement in nutrient cycling...

  13. Recurring patterns in bacterioplankton dynamics during coastal spring algae blooms.

    Science.gov (United States)

    Teeling, Hanno; Fuchs, Bernhard M; Bennke, Christin M; Krüger, Karen; Chafee, Meghan; Kappelmann, Lennart; Reintjes, Greta; Waldmann, Jost; Quast, Christian; Glöckner, Frank Oliver; Lucas, Judith; Wichels, Antje; Gerdts, Gunnar; Wiltshire, Karen H; Amann, Rudolf I

    2016-01-01

    A process of global importance in carbon cycling is the remineralization of algae biomass by heterotrophic bacteria, most notably during massive marine algae blooms. Such blooms can trigger secondary blooms of planktonic bacteria that consist of swift successions of distinct bacterial clades, most prominently members of the Flavobacteriia, Gammaproteobacteria and the alphaproteobacterial Roseobacter clade. We investigated such successions during spring phytoplankton blooms in the southern North Sea (German Bight) for four consecutive years. Dense sampling and high-resolution taxonomic analyses allowed the detection of recurring patterns down to the genus level. Metagenome analyses also revealed recurrent patterns at the functional level, in particular with respect to algal polysaccharide degradation genes. We, therefore, hypothesize that even though there is substantial inter-annual variation between spring phytoplankton blooms, the accompanying succession of bacterial clades is largely governed by deterministic principles such as substrate-induced forcing. PMID:27054497

  14. Production of transparent exopolymer particles (TEP) by phyto- and bacterioplankton

    OpenAIRE

    Passow, Uta

    2002-01-01

    Transparent exopolymer particles (TEP) exist abundantly in oceans and lakes and have been found to play an important role for sedimentation and biochemical cycling of matter. But the origin of these particles and the factors regulating their formation are not well understood. This study examined several strains of algae and bacteria with respect to their production of TEP or TEP-precursors. The formation rate of TEP in batch cultures of algae varied widely between species, and interspecies va...

  15. Relevance of bacterioplankton abundance and production in the oligotrophic equatorial Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, V.; Rodrigues, V.; Ramaiah, N.; Paul, J.T.

    to dusk were done at alternate stations. Chlorophyll a Chlorophyll a (Chl a) concentrations were measured fluorometrically (Turner Designs, USA, 10-AU-005-CE) by filtering one litre water samples from each depth onto GF/F filters and extracting... size, Whatman, USA). The filters were transferred to scintillation vials and exposed overnight to HCl (0.5 N) fumes in a closed container to drive off any inorganic 14 C adhering to samples. Five ml liquid scintillation cocktail (Sisco Research...

  16. Response of bacterioplankton to iron fertilization of the Southern Ocean, Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, S.K.; Kotakonda, A.; Kapardar, R.K.; Kankipati, H.K.; Rao, P.S.; Sankaranarayanan, P.M.; Vetaikorumagan, S.R.; Gundlapally, S.R.; Ramaiah, N.; Shivaji, S.

    organic matter (Kirchman, 1990; Kirchman and Rich, 1997), inorganic nutrients (Cotner et al., 1997) and micronutrients like iron (Pakulski et al., 1996; Church et al., 2000) which positively influence the growth of bacteria would have a negative impact...

  17. Contrasted Effects of Diversity and Immigration on Ecological Insurance in Marine Bacterioplankton Communities

    OpenAIRE

    Thierry Bouvier; Patrick Venail; Thomas Pommier; Corinne Bouvier; Claire Barbera; Nicolas Mouquet

    2012-01-01

    The ecological insurance hypothesis predicts a positive effect of species richness on ecosystem functioning in a variable environment. This effect stems from temporal and spatial complementarity among species within metacommunities coupled with optimal levels of dispersal. Despite its importance in the context of global change by human activities, empirical evidence for ecological insurance remains scarce and controversial. Here we use natural aquatic bacterial communities to explore some of ...

  18. Zonation of bacterioplankton communities along aging upwelled water in the northern Benguela upwelling

    Directory of Open Access Journals (Sweden)

    Benjamin eBergen

    2015-06-01

    Full Text Available Upwelling areas are shaped by enhanced primary production in surface waters, accompanied by a well-investigated planktonic succession. Although bacteria play an important role in biogeochemical cycles of upwelling systems, little is known about bacterial community composition and its development during upwelling events. The aim of this study was to investigate the succession of bacterial assemblages in aging upwelled water of the Benguela upwelling from coastal to offshore sites. Water from the upper mixed layer at 12 stations was sampled along two transects from the origin of the upwelling to a distance of 220 km. 16S rRNA gene amplicon sequencing was then used in a bacterial diversity analysis and major bacterial taxa were quantified by catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH. Additionally, bacterial cell numbers and bacterial production were assessed . Community statistical analysis revealed a reproducible zonation along the two transects, with four clusters of significantly different microbial assemblages. Clustering was mainly driven by phytoplankton composition and abundance. Similar to the temporal succession that occurs during phytoplankton blooms in temperate coastal waters, operational taxonomic units (OTUs affiliated with Bacteroidetes and Gammaproteobacteria were dominant during algal blooming whereas Pelagibacterales were highly abundant in regions with low algal abundance. The most dominant heterotrophic OTU (9% of all reads was affiliated with Pelagibacterales and showed a strong negative correlation with phytoplankton. By contrast, the second most abundant heterotrophic OTU (6% of all reads was affiliated with the phylum Verrucomicrobia and correlated positively with phytoplankton. Together with the close relation of bacterial production and phytoplankton abundance, our results showed that bacterial community dynamics is strongly driven by the development and composition of the phytoplankton community.

  19. Natural variation in SAR11 marine bacterioplankton genomes inferred from metagenomic data

    OpenAIRE

    Wilhelm Larry J; Tripp H James; Givan Scott A; Smith Daniel P; Giovannoni Stephen J

    2007-01-01

    Abstract Background One objective of metagenomics is to reconstruct information about specific uncultured organisms from fragmentary environmental DNA sequences. We used the genome of an isolate of the marine alphaproteobacterium SAR11 ('Candidatus Pelagibacter ubique'; strain HTCC1062), obtained from the cold, productive Oregon coast, as a query sequence to study variation in SAR11 metagenome sequence data from the Sargasso Sea, a warm, oligotrophic ocean gyre. Results The average amino acid...

  20. Allochthonous Carbon-a Major Driver of Bacterioplankton Production in the Subarctic Northern Baltic Sea.

    Science.gov (United States)

    Figueroa, D; Rowe, O F; Paczkowska, J; Legrand, C; Andersson, A

    2016-05-01

    Heterotrophic bacteria are, in many aquatic systems, reliant on autochthonous organic carbon as their energy source. One exception is low-productive humic lakes, where allochthonous dissolved organic matter (ADOM) is the major driver. We hypothesized that bacterial production (BP) is similarly regulated in subarctic estuaries that receive large amounts of riverine material. BP and potential explanatory factors were measured during May-August 2011 in the subarctic Råne Estuary, northern Sweden. The highest BP was observed in spring, concomitant with the spring river-flush and the lowest rates occurred during summer when primary production (PP) peaked. PLS correlations showed that ∼60 % of the BP variation was explained by different ADOM components, measured as humic substances, dissolved organic carbon (DOC) and coloured dissolved organic matter (CDOM). On average, BP was threefold higher than PP. The bioavailability of allochthonous dissolved organic carbon (ADOC) exhibited large spatial and temporal variation; however, the average value was low, ∼2 %. Bioassay analysis showed that BP in the near-shore area was potentially carbon limited early in the season, while BP at seaward stations was more commonly limited by nitrogen-phosphorus. Nevertheless, the bioassay indicated that ADOC could contribute significantly to the in situ BP, ∼60 %. We conclude that ADOM is a regulator of BP in the studied estuary. Thus, projected climate-induced increases in river discharge suggest that BP will increase in subarctic coastal areas during the coming century. PMID:26677860

  1. Biogeography of pelagic bacterioplankton across an antagonistic temperature-salinity gradient in the Red Sea

    KAUST Repository

    Ngugi, David

    2011-12-01

    The Red Sea is a unique marine ecosystem with contrasting gradients of temperature and salinity along its north-to-south axis. It is an extremely oligotrophic environment that is characterized by perpetual year-round water column stratification, high annual solar irradiation, and negligible riverine and precipitation inputs. In this study, we investigated whether the contemporary environmental conditions shape community assemblages by pyrosequencing 16S rRNA genes of bacteria in surface water samples collected from the northeastern half of this water body. A combined total of 1855 operational taxonomic units (OTUs) were recovered from the \\'small-cell\\' and \\'large-cell\\' fractions. Here, a few major OTUs affiliated with Cyanobacteria and Proteobacteria accounted for â93% of all sequences, whereas a tail of \\'rare\\' OTUs represented most of the diversity. OTUs allied to Surface 1a/b SAR11 clades and Prochlorococcus related to the high-light-adapted (HL2) ecotype were the most widespread and predominant sequence types. Interestingly, the frequency of taxa that are typically found in the upper mesopelagic zone was significantly elevated in the northern transects compared with those in the central, presumably as a direct effect of deep convective mixing in the Gulf of Aqaba and water exchange with the northern Red Sea. Although temperature was the best predictor of species richness across all major lineages, both spatial and environmental distances correlated strongly with phylogenetic distances. Our results suggest that the bacterial diversity of the Red Sea is as high as in other tropical seas and provide evidence for fundamental differences in the biogeography of pelagic communities between the northern and central regions. © 2011 Blackwell Publishing Ltd.

  2. Nitrogenase expression in estuarine bacterioplankton influenced by organic carbon and availability of oxygen

    DEFF Research Database (Denmark)

    Severin, Ina; Bentzon-Tilia, Mikkel; Moisander, Pia H.;

    2015-01-01

    carbon and inhibition by oxygen constrain N fixation by diazotrophs in coastal seawater. The goal was to test whether by alleviating these constraints an increased overlap between nitrogenase (nifH)-gene- carrying and -expressing organisms could be achieved. We incubated water from a eutrophic but N......-limited fjord in Denmark under high carbon/low oxygen conditions and determined bacterial growth and production, diazotrophic community composition (Illumina nifH amplicon sequencing), and nifH gene abundance and expression (quantitative PCR (qPCR) and quantitative Reverse Transcriptase PCR (q......RT-PCR)). Bacterial abundances and production increased under high carbon/low oxygen conditions as did the similarity between present and active diazotrophic communities. This was caused by the loss of specific abundant yet non-active gammaproteobacterial phylotypes and increased expression by others. The prominent...

  3. Seasonal dynamics and community structure of bacterioplankton in upper Paraná River floodplain.

    Science.gov (United States)

    Chiaramonte, Josiane Barros; Roberto, Maria do Carmo; Pagioro, Thomaz Aurélio

    2013-11-01

    Knowing the bacterial community, as well as understanding how it changes during a hydrological pulse, is very important to understand nutrient cycles in floodplain systems. The bacterial community structure was analyzed in the 12 sites of upper Paraná River floodplain, and its changes during a flood pulse were described. In order to understand how high and low water phases change bacterial community by changing abiotical variables, the bacterial community distribution was determined in superficial water of 12 different sampling stations, every 3 months, from December 2010 to September 2011. The bacterial community structure and diversity was analyzed by fluorescent in situ hybridization, considering the main domains Bacteria and Archaea and the subdivisions of the phylum Proteobacteria (Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria) and the Cytophaga-Flavobacterium cluster. Smaller densities were observed on ebb and low water periods and the highest density was observed in March 2011. The high water period caused a decrease in diversity because of the lost of equitability. The highest values of Shannon-Wiener index were found on December 2010 and September 2011. The nutrients runoff to the aquatic environments of the floodplain promoted an increase in the total bacterial density during the high water phase as well as changes in bacterial community composition. The bacterial community presented both spatial and temporal differences. Yet, temporal changes in limnological characteristics of the floodplain were the most important predictor of bacterial community and also influenced its diversity. PMID:24046074

  4. Temporal changes in the bacterioplankton of a Northeast Ohio (USA) River.

    Science.gov (United States)

    Liu, J; Leff, L G

    2002-12-01

    To examine temporal changes in a bacterial community, water samples were collected monthly for one year from five sites along a major use-reuse river, the Cuyahoga River, in northeastern Ohio (USA). Fluorescent in situ hybridization (FISH) was used to enumerate population sizes of two species of common bacteria, Pseudomonas putida and Acinetobacter calcoaceticus; FISH was also performed with a Domain Bacteria specific probe. In addition, the total bacteria (based on DAPI staining), colony forming units (on modified Nutrient agar) and coliforms were enumerated and supporting physical/chemical data were collected. Each variable examined exhibited a different seasonal pattern. Temporal changes in total number of bacteria and population size of P. putida were correlated with turbidity and precipitation suggesting that allochthonous sources and scouring of the benthos may be major contributors to these portions of the community. In contrast, the number of cells hybridizing the Domain Bacteria and A. calcoaceticus probes were correlated with temperature. Thus, different aspects of the bacterial community are potentially controlled by different factors and the role of allochthonous and autochthonous sources may vary among species. PMID:14552350

  5. Bacterioplankton and organic carbon dynamics in the lower mesohaline chesapeake bay.

    Science.gov (United States)

    Jonas, R B; Tuttle, J H

    1990-03-01

    The mesohaline portion of the Chesapeake Bay is subject to annual summertime hypoxia and anoxia in waters beneath the pycnocline. This dissolved oxygen deficit is directly related to salinity-based stratification of the water column in combination with high levels of autochthonously produced organic matter and a very high abundance of metabolically active bacteria. Throughout the water column in the lower, mesohaline part of the bay, between the Potomac and Rappahannock rivers, near the southern limit of the mainstem anoxia, bacterial abundance often exceeded 10 x 10 cells per ml and bacterial production exceeded 7 x 10 cells per liter per day during summer. Bacterial biomass averaged 34% (range, 16 to 126%) of the phytoplankton biomass in summer. These values are equal to or greater than those found farther north in the bay, where the oxygen deficit is more severe. Seasonal variations in bacterial abundance and production were correlated with phytoplankton biomass (lag time, 7 to 14 days), particulate organic carbon and nitrogen, and particulate biochemical oxygen demand in spring; but during summer, they were significantly correlated only with dissolved biochemical oxygen demand. During summer, dissolved biochemical oxygen demand can account for 50 to 60% of the total biochemical oxygen demand throughout the water column and 80% in the bottom waters. There is a clear spring-summer seasonal shift in the production of organic matter and in the coupling of bacteria and autochthonous organic matter. The measurement of dissolved, microbially labile organic matter concentrations is crucial in understanding the trophic dynamics of the lower mesohaline part of the bay. The absolute levels of organic matter in the water column and the bacterial-organic carbon relationships suggest that a lower bay source of organic matter fuels the upper mesohaline bay oxygen deficits. PMID:16348148

  6. Transcriptional response of bathypelagic marine bacterioplankton to the Deepwater Horizon oil spill.

    Science.gov (United States)

    Rivers, Adam R; Sharma, Shalabh; Tringe, Susannah G; Martin, Jeffrey; Joye, Samantha B; Moran, Mary Ann

    2013-12-01

    The Deepwater Horizon blowout released a massive amount of oil and gas into the deep ocean between April and July 2010, stimulating microbial blooms of petroleum-degrading bacteria. To understand the metabolic response of marine microorganisms, we sequenced ≈ 66 million community transcripts that revealed the identity of metabolically active microbes and their roles in petroleum consumption. Reads were assigned to reference genes from ≈ 2700 bacterial and archaeal taxa, but most assignments (39%) were to just six genomes representing predominantly methane- and petroleum-degrading Gammaproteobacteria. Specific pathways for the degradation of alkanes, aromatic compounds and methane emerged from the metatranscriptomes, with some transcripts assigned to methane monooxygenases representing highly divergent homologs that may degrade either methane or short alkanes. The microbial community in the plume was less taxonomically and functionally diverse than the unexposed community below the plume; this was due primarily to decreased species evenness resulting from Gammaproteobacteria blooms. Surprisingly, a number of taxa (related to SAR11, Nitrosopumilus and Bacteroides, among others) contributed equal numbers of transcripts per liter in both the unexposed and plume samples, suggesting that some groups were unaffected by the petroleum inputs and blooms of degrader taxa, and may be important for re-establishing the pre-spill microbial community structure. PMID:23902988

  7. Salinity as a structuring factor for the composition and performance of bacterioplankton degrading riverine DOC.

    Science.gov (United States)

    Langenheder, Silke; Kisand, Veljo; Wikner, Johan; Tranvik, Lars J

    2003-07-01

    Abstract The impact of salinity on the composition and functional performance (biomass production, growth efficiency and growth rates) of bacterial communities was investigated using batch cultures growing on dissolved organic carbon from a river draining into the Northern Baltic Sea. The cultures were adjusted to riverine or estuarine salinity levels and inoculated with bacteria from these two environments. Bacterial growth efficiencies differed in response to salinity and the origin of the inoculum. When salinity was adjusted to correspond to the salinity at the site where the inoculum was retrieved, growth efficiency was relatively high (11.5+/-2.6%). However, when bacteria were confronted with a shift in salinity, growth efficiency was lower (7.5+/-2.0%) and more of the utilized carbon was respired. In contrast, growth rates were higher when bacteria were exposed to a change in salinity. The composition of the bacterial communities developing in the batch cultures differed, as shown by 16S rDNA DGGE, depending on the origin of the inoculum and salinity. Reverse and direct DNA-DNA hybridization revealed salinity optima in the growth of specific bacterial strains as well as broader phylogenetic groups. Strains belonging to the alpha- and beta-Proteobacteria, Actinobacteria and gamma-Proteobacteria other than the genus Pseudomonas showed higher relative abundance under freshwater conditions, whereas strains of the genus Pseudomonas and the Cytophaga-Flavobacterium-Bacteroides group were favored by estuarine conditions. Generally, our results demonstrate functional changes associated with changes in community composition. We suggest that even moderate changes in salinity affect bacterial community composition, which subsequently leads to altered growth characteristics. PMID:19719630

  8. Transplant experiments uncover Baltic Sea basin-specific responses in bacterioplankton community composition and metabolic activities.

    Science.gov (United States)

    Lindh, Markus V; Figueroa, Daniela; Sjöstedt, Johanna; Baltar, Federico; Lundin, Daniel; Andersson, Agneta; Legrand, Catherine; Pinhassi, Jarone

    2015-01-01

    Anthropogenically induced changes in precipitation are projected to generate increased river runoff to semi-enclosed seas, increasing loads of terrestrial dissolved organic matter and decreasing salinity. To determine how bacterial community structure and functioning adjust to such changes, we designed microcosm transplant experiments with Baltic Proper (salinity 7.2) and Bothnian Sea (salinity 3.6) water. Baltic Proper bacteria generally reached higher abundances than Bothnian Sea bacteria in both Baltic Proper and Bothnian Sea water, indicating higher adaptability. Moreover, Baltic Proper bacteria growing in Bothnian Sea water consistently showed highest bacterial production and beta-glucosidase activity. These metabolic responses were accompanied by basin-specific changes in bacterial community structure. For example, Baltic Proper Pseudomonas and Limnobacter populations increased markedly in relative abundance in Bothnian Sea water, indicating a replacement effect. In contrast, Roseobacter and Rheinheimera populations were stable or increased in abundance when challenged by either of the waters, indicating an adjustment effect. Transplants to Bothnian Sea water triggered the initial emergence of particular Burkholderiaceae populations, and transplants to Baltic Proper water triggered Alteromonadaceae populations. Notably, in the subsequent re-transplant experiment, a priming effect resulted in further increases to dominance of these populations. Correlated changes in community composition and metabolic activity were observed only in the transplant experiment and only at relatively high phylogenetic resolution. This suggested an importance of successional progression for interpreting relationships between bacterial community composition and functioning. We infer that priming effects on bacterial community structure by natural episodic events or climate change induced forcing could translate into long-term changes in bacterial ecosystem process rates. PMID:25883589

  9. Transcriptional response of bathypelagic marine bacterioplankton to the Deepwater Horizon oil spill

    OpenAIRE

    Rivers, Adam R; Sharma, Shalabh; Tringe, Susannah G.; Martin, Jeffrey; Joye, Samantha B.; Moran, Mary Ann

    2013-01-01

    The Deepwater Horizon blowout released a massive amount of oil and gas into the deep ocean between April and July 2010, stimulating microbial blooms of petroleum-degrading bacteria. To understand the metabolic response of marine microorganisms, we sequenced ∼66 million community transcripts that revealed the identity of metabolically active microbes and their roles in petroleum consumption. Reads were assigned to reference genes from ∼2700 bacterial and archaeal taxa, but most assignments (39...

  10. Linking Activity and Function to Ecosystem Dynamics in a Coastal Bacterioplankton Community

    Directory of Open Access Journals (Sweden)

    Scott Michael Gifford

    2014-04-01

    Full Text Available For bacterial communities containing hundreds to thousands of distinct populations, connecting functional processes and environmental dynamics at high taxonomic resolution has remained challenging. Here we use the expression of ribosomal proteins (%RP as a proxy for in situ activity of 200 taxa within 20 metatranscriptomic samples in a coastal ocean time series encompassing both seasonal variability and diel dynamics. %RP patterns grouped the taxa into seven activity clusters with distinct profiles in functional gene expression and correlations with environmental gradients. Clusters 1-3 had their highest potential activity in the winter and fall, and included some of the most active taxa, while Clusters 4-7 had their highest potential activity in the spring and summer. Cluster 1 taxa were characterized by gene expression for motility and complex carbohydrate degradation (dominated by Gammaproteobacteria and Bacteroidetes, and Cluster 2 taxa by transcription of genes for amino acid and aromatic compound metabolism and aerobic anoxygenic phototrophy (Roseobacter. Other activity clusters were enriched in transcripts for proteorhodopsin and methylotrophy (Cluster 4; SAR11 and methylotrophs, photosynthesis and attachment (Clusters 5 and 7; Synechococcus, picoeukaryotes, Verucomicrobia, and Planctomycetes, and sulfur oxidation (Cluster 7; Gammaproteobacteria. The seasonal patterns in activity were overlain, and sometimes obscured, by large differences in %RP over shorter day-night timescales. Seventy-eight taxa, many of them heterotrophs, had a higher %RP activity index during the day than night, indicating strong diel activity at this coastal site. Emerging from these taxonomically- and time-resolved estimates of in situ microbial activity are predictions of specific ecological groupings of microbial taxa in a dynamic coastal environment.

  11. Natural variation in SAR11 marine bacterioplankton genomes inferred from metagenomic data

    Directory of Open Access Journals (Sweden)

    Wilhelm Larry J

    2007-11-01

    Full Text Available Abstract Background One objective of metagenomics is to reconstruct information about specific uncultured organisms from fragmentary environmental DNA sequences. We used the genome of an isolate of the marine alphaproteobacterium SAR11 ('Candidatus Pelagibacter ubique'; strain HTCC1062, obtained from the cold, productive Oregon coast, as a query sequence to study variation in SAR11 metagenome sequence data from the Sargasso Sea, a warm, oligotrophic ocean gyre. Results The average amino acid identity of SAR11 genes encoded by the metagenomic data to the query genome was only 71%, indicating significant evolutionary divergence between the coastal isolates and Sargasso Sea populations. However, an analysis of gene neighbors indicated that SAR11 genes in the Sargasso Sea metagenomic data match the gene order of the HTCC1062 genome in 96% of cases (> 85,000 observations, and that rearrangements are most frequent at predicted operon boundaries. There were no conserved examples of genes with known functions being found in the coastal isolates, but not the Sargasso Sea metagenomic data, or vice versa, suggesting that core regions of these diverse SAR11 genomes are relatively conserved in gene content. However, four hypervariable regions were observed, which may encode properties associated with variation in SAR11 ecotypes. The largest of these, HVR2, is a 48 kb region flanked by the sole 5S and 23S genes in the HTCC1062 genome, and mainly encodes genes that determine cell surface properties. A comparison of two closely related 'Candidatus Pelagibacter' genomes (HTCC1062 and HTCC1002 revealed a number of "gene indels" in core regions. Most of these were found to be polymorphic in the metagenomic data and showed evidence of purifying selection, suggesting that the same "polymorphic gene indels" are maintained in physically isolated SAR11 populations. Conclusion These findings suggest that natural selection has conserved many core features of SAR11 genomes across broad oceanic scales, but significant variation was found associated with four hypervariable genome regions. The data also led to the hypothesis that some gene insertions and deletions might be polymorphisms, similar to allelic polymorphisms.

  12. Strong variability in bacterioplankton abundance and production in central and western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, V.; Ramaiah, N; Paul, J.T.; Sardessai, S; Jyothibabu, R.; Gauns, M

    (average of 1.46 pM h sup (-1)) and WB (average of 1.40 pM h sup (-1)) were less than those from the northwestern Indian Ocean. These abundances and uptake rates were higher than those in the oligotrophic northwestern Sargasso Sea (less than 7 x 10 sup (8...

  13. Pollution impacts on bacterioplankton diversity in a tropical urban coastal lagoon system.

    Directory of Open Access Journals (Sweden)

    Gigliola R B Salloto

    Full Text Available Despite a great number of published studies addressing estuarine, freshwater and marine bacterial diversity, few have examined urban coastal lagoons in tropical habitats. There is an increasing interest in monitoring opportunistic pathogens as well as indigenous microbial community members in these water bodies by current molecular and microbiological approaches. In this work, bacterial isolates were obtained through selective plate dilution methods to evaluate antibiotic resistances. In addition, 16S rRNA gene libraries were prepared from environmental waters and mixed cultures grown in BHI medium inoculated with Jacarepaguá lagoon waters. Denaturing gradient gel electrophoresis (DGGE analyses showed distinct community profiles between environmental communities from each studied site and their cultured counterparts. A total of 497 bacterial sequences were analyzed by MOTHUR, yielding 245 operational taxonomic units (OTUs grouped at 97% similarity. CCA diagrams showcased how several environmental variables affect the distribution of 18 bacterial orders throughout the three distinct habitats. UniFrac metrics and Venn diagrams revealed that bacterial communities retrieved through each experimental approach were significantly different and that only one OTU, closely related to Vibrio cholerae, was shared between them. Potentially pathogenic bacteria were isolated from most sampled environments, fifty percent of which showed antibiotic resistance.

  14. Influence of Salinity on Bacterioplankton Communities from the Brazilian Rain Forest to the Coastal Atlantic Ocean

    OpenAIRE

    Silveira, Cynthia B; Ricardo P Vieira; Alexander M Cardoso; Paranhos, Rodolfo; Rodolpho M Albano; Martins, Orlando B.

    2011-01-01

    Background Planktonic bacteria are recognized as important drivers of biogeochemical processes in all aquatic ecosystems, however, the taxa that make up these communities are poorly known. The aim of this study was to investigate bacterial communities in aquatic ecosystems at Ilha Grande, Rio de Janeiro, Brazil, a preserved insular environment of the Atlantic rain forest and how they correlate with a salinity gradient going from terrestrial aquatic habitats to the coastal Atlantic Ocean. Meth...

  15. Biomass reallocation within freshwater bacterioplankton induced by manipulating phosphorus availability and grazing

    Czech Academy of Sciences Publication Activity Database

    Posch, T.; Mindl, B.; Horňák, Karel; Jezbera, Jan; Salcher, M.M.; Sattler, B.; Sonntag, B.; Vrba, Jaroslav; Šimek, Karel

    2007-01-01

    Roč. 49, č. 3 (2007), s. 223-232. ISSN 0948-3055 R&D Projects: GA ČR(CZ) GA206/05/0007 Grant ostatní: ASF(AT) FWF P17554-B06 Institutional research plan: CEZ:AV0Z60170517 Keywords : bacterial biomass * bacteria-flagellate interactions * fluorescence in situ hybridization Subject RIV: EH - Ecology, Behaviour Impact factor: 2.385, year: 2007

  16. Alkaline phosphatases in microbialites and bacterioplankton from Alchichica soda lake, Mexico

    Czech Academy of Sciences Publication Activity Database

    Valdespino-Castillo, P.M.; Alcantara-Hernandez, R.J.; Alcocer, J.; Merino-Ibarra, M.; Macek, Miroslav; Falcon, L.I.

    2014-01-01

    Roč. 90, č. 2 (2014), s. 504-519. ISSN 0168-6496 Institutional support: RVO:60077344 Keywords : dissolved organic phosphorus utilization * extracellular enzymes * microbial functional diversity Subject RIV: EE - Microbiology, Virology Impact factor: 3.568, year: 2014

  17. Stimulation of viral infection of bacterioplankton during a mesoscale iron fertilization experiment in the Southern Ocean

    Science.gov (United States)

    Weinbauer, M. G.; Arrieta, J.-M.; Herndl, G. J.

    2003-04-01

    A mesoscale iron fertilization in the Southern Ocean (Eisenex ) induced a phytoplankton bloom within three weeks observation as well as in an increased bacterial abundance and production. Viral abundance and viral production were stimulated as well. A virus-dilution approach was used to estimate the frequency of infected cells (FIC) and the frequency of lysogenic cells (FLC), i.e. cells with a dormant viral genome. While the FLC did not vary strongly within the iron-enriched patch and did not differ from waters outside the patch, FIC increased significantly within the iron fertilized patch. This suggests that induction of the lytic cycle in lysogenic cells was not significant. Rather, the stimulated bacterial production and abundance within the patch resulted in higher and more successful encounters between viruses and hosts and thus in higher FIC values. Consequently, the iron fertilization enhanced the influence of viral infection in the microbial food web. According to the current model, this should result a stimulation of bacterial production, since lysed bacterial cells cannot be consumed up by protists and transferred to higher trophic level; lysis products can be taken up by bacteria and thus organic carbon spins within this viral loop. Viral infection is a significant and previously overlooked factor in the carbon flow during iron fertilization experiments.

  18. Spatial diversity of bacterioplankton communities in surface water of northern South China Sea.

    Directory of Open Access Journals (Sweden)

    Jialin Li

    Full Text Available The South China Sea is one of the largest marginal seas, with relatively frequent passage of eddies and featuring distinct spatial variation in the western tropical Pacific Ocean. Here, we report a phylogenetic study of bacterial community structures in surface seawater of the northern South China Sea (nSCS. Samples collected from 31 sites across large environmental gradients were used to construct clone libraries and yielded 2,443 sequences grouped into 170 OTUs. Phylogenetic analysis revealed 23 bacterial classes with major components α-, β- and γ-Proteobacteria, as well as Cyanobacteria. At class and genus taxon levels, community structure of coastal waters was distinctively different from that of deep-sea waters and displayed a higher diversity index. Redundancy analyses revealed that bacterial community structures displayed a significant correlation with the water depth of individual sampling sites. Members of α-Proteobacteria were the principal component contributing to the differences of the clone libraries. Furthermore, the bacterial communities exhibited heterogeneity within zones of upwelling and anticyclonic eddies. Our results suggested that surface bacterial communities in nSCS had two-level patterns of spatial distribution structured by ecological types (coastal VS. oceanic zones and mesoscale physical processes, and also provided evidence for bacterial phylogenetic phyla shaped by ecological preferences.

  19. Pollution Impacts on Bacterioplankton Diversity in a Tropical Urban Coastal Lagoon System

    OpenAIRE

    Salloto, Gigliola R. B.; Cardoso, Alexander M.; Coutinho, Felipe H; Pinto, Leonardo H.; Vieira, Ricardo P.; Chaia, Catia; Lima, Joyce L.; Rodolpho M. Albano; Martins, Orlando B.; Maysa M. Clementino

    2012-01-01

    Despite a great number of published studies addressing estuarine, freshwater and marine bacterial diversity, few have examined urban coastal lagoons in tropical habitats. There is an increasing interest in monitoring opportunistic pathogens as well as indigenous microbial community members in these water bodies by current molecular and microbiological approaches. In this work, bacterial isolates were obtained through selective plate dilution methods to evaluate antibiotic resistances. In addi...

  20. Major effect of hydrogen peroxide on bacterioplankton metabolism in the Northeast Atlantic.

    Directory of Open Access Journals (Sweden)

    Federico Baltar

    Full Text Available Reactive oxygen species such as hydrogen peroxide have the potential to alter metabolic rates of marine prokaryotes, ultimately impacting the cycling and bioavailability of nutrients and carbon. We studied the influence of H2O2 on prokaryotic heterotrophic production (PHP and extracellular enzymatic activities (i.e., β-glucosidase [BGase], leucine aminopeptidase [LAPase] and alkaline phosphatase [APase] in the subtropical Atlantic. With increasing concentrations of H2O2 in the range of 100-1000 nM, LAPase, APase and BGase were reduced by up to 11, 23 and 62%, respectively, in the different water layers. Incubation experiments with subsurface waters revealed a strong inhibition of all measured enzymatic activities upon H2O2 amendments in the range of 10-500 nM after 24 h. H2O2 additions also reduced prokaryotic heterotrophic production by 36-100% compared to the rapid increases in production rates occurring in the unamended controls. Our results indicate that oxidative stress caused by H2O2 affects prokaryotic growth and hydrolysis of specific components of the organic matter pool. Thus, we suggest that oxidative stress may have important consequences on marine carbon and energy fluxes.

  1. Comparing the effects of resource enrichment and grazing on a bacterioplankton community of a meso-eutrophic reservoir

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Horňák, K.; Mašín, M.; Christaki, U.; Nedoma, Jiří; Weinbauer, M. G.; Dolan, J. R.

    2003-01-01

    Roč. 31, č. 2 (2003), s. 123-135. ISSN 0948-3055 R&D Projects: GA ČR GA206/99/0028; GA ČR GA206/02/0003; GA MŠk KONTAKT 22-2000/9513514 Grant ostatní: CNRS(FR) PICS 1111 Institutional research plan: CEZ:MSM 123100004 Keywords : reservoir * top-down and bottom-up control * microbial food webs Subject RIV: EE - Microbiology, Virology Impact factor: 2.116, year: 2003

  2. Specific activity of cell-surface acid phosphatase in different bacterioplankton morphotypes in an acidified mountain lake

    Czech Academy of Sciences Publication Activity Database

    Nedoma, Jiří; Vrba, Jaroslav

    2006-01-01

    Roč. 8, č. 7 (2006), s. 1271-1279. ISSN 1462-2912 R&D Projects: GA AV ČR(CZ) IAA6017202 Institutional research plan: CEZ:AV0Z60170517 Keywords : alkaline phosphatase * bacterial morphorypes * acid ified lake Subject RIV: CE - Biochemistry Impact factor: 4.630, year: 2006

  3. pH Tolerance in Freshwater Bacterioplankton: Trait Variation of the Community as Measured by Leucine Incorporation

    OpenAIRE

    Bååth, Erland; Kritzberg, Emma

    2015-01-01

    pH is an important factor determining bacterial community composition in soil and water. We have directly determined the community tolerance (trait variation) to pH in communities from 22 lakes and streams ranging in pH from 4 to 9 using a growth-based method not relying on distinguishing between individual populations. The pH in the water samples was altered to up to 16 pH values, covering in situ pH ± 2.5 U, and the tolerance was assessed by measuring bacterial growth (Leu incorporation) in...

  4. Influence of allochthonous organic matter on bacterioplankton biomass and activity in a eutrophic, sub-tropical estuary

    Science.gov (United States)

    Barrera-Alba, José Juan; Gianesella, Sônia Maria Flores; Moser, Gleyci Aparecida Oliveira; Saldanha-Corrêa, Flávia Marisa Prado

    2009-03-01

    Heterotrophic bacterial and phytoplankton biomass, production, specific growth rates, and growth efficiencies were studied in the Northern region of the Cananéia-Iguape estuarine system, which has recently experienced an intense eutrophication due to anthropogenic causes. Two surveys were carried out during spring and neap tide periods of the dry season of 2005 and the rainy season of 2006. This region receives large freshwater inputs with organic seston and phosphate concentrations that reach as high as 1.0 mg l -1 and 20.0 μM, respectively. Strong decreasing gradients of seston and dissolved inorganic nutrients were observed from the river/estuary boundary to the estuary/coastal interface. Gradients were also observed in phytoplankton and bacterial production rates. The production rates of phytoplankton were 5.6-fold higher (mean 8.5 μg C l -1 h -1) during the dry season. Primary production rates (PP) positively correlated with salinity and euphotic depth, indicating that phytoplankton productivity was light-limited. On the other hand, bacterial biomass (BB) and production rates (BP) were 1.9- and 3.7-fold higher, respectively, during the rainy season, with mean values of up to 40.4 μg C l -1 and 7.9 μg C l -1 h -1, respectively. Despite such a high BP, bacterial abundance remained 20 were registered during high freshwater input, suggesting that under these conditions, bacterial activity was predominantly supported by allochthonous inputs of organic carbon. In addition, BB probably represented the main pathway for the synthesis of high-quality (low C:N) biomass that may have been available to the heterotrophic components of the plankton food web, particularly nanoheterotrophs.

  5. Assemblages' structure and activity of bacterioplankton in northern Adriatic Sea surface waters: a 3-year case study.

    Science.gov (United States)

    Celussi, Mauro; Bussani, Andrea; Cataletto, Bruno; Del Negro, Paola

    2011-01-01

    The bacterial community, both in terms of community structure (denaturing gradient gel electrophoresis fingerprinting) and activity (exoenzymatic hydrolysis of proteins, polysaccharides and phosphorylated molecules and leucine uptake), was investigated seasonally for 3 years (2004-2006) in a large-scale grid in the northern Adriatic Sea. A high variability characterized the spatial structure of bacterial assemblages and a scarce seasonality was found in all the nine studied stations. Bacterial communities were substantially diverse in the same season of the 3 years, in contrast to what was reported previously for oceanic sites. Assemblages were in general strongly affected by river inputs, especially in spring, when freshwater loads were higher. Finally, a close relationship was found between given assemblages and their patterns of degradation/production activities by applying a multivariate analysis (linear discriminant analysis) to the dataset. The high variability of bacterial community structures and patterns of activity may indicate an ecological response to the high dynamism that characterizes the basin both on a physical and on a biological basis. PMID:21091521

  6. Temperature and solar radiation interactions on 3H-leucine incorporation by bacterioplankton in a subtropical estuary.

    Science.gov (United States)

    Bullock, Avery K; Jeffrey, Wade H

    2010-01-01

    Although the effects of UV radiation are thought to be temperature independent, the photoinhibition of aquatic bacteria may be temperature dependent owing to enzymatic repair kinetics, an important consideration for climate change analyses. We examined the interactions between temperature and solar radiation in water samples collected from the Blackwater River, Pensacola Bay, and the coastal Gulf of Mexico (Florida) in July 2008. Subsamples were incubated in the dark for 20 h at either the in situ temperature, +5 degrees C from in situ or -5 degrees C from in situ after which they were amended with (3)H-leucine and irradiated in full sunlight at their respective temperatures and compared to samples incubated simultaneously in the dark. Temperature and light significantly affected (3)H-leucine incorporation at all locations and interactive effects between temperature and sunlight were found for Pensacola Bay and the Gulf. Generally, warmer waters reduced photoinhibition. The -5 degrees C treatment was always significantly more inhibited than the +5 degrees C treatment, but the in situ temperature and +5 degrees C and -5 degrees C treatments were not always significantly different. Photoinhibition reduction at warmer temperatures suggests specific effects on photobiology not observed in general cellular activity may be important in determining interactive ecosystem effects of climate change. PMID:20158671

  7. [Variation of bacterioplankton number in the north-western part of the Black Sea depending on hydrological and hydrochemical factors].

    Science.gov (United States)

    Kovaleva, N V

    2003-01-01

    Quantitative analysis of total bacteria numbers variations under influence of river outflow and development of anaerobic conditions has been carried out on the basis of long-term field research in the north-western part of the Black Sea. The regressive equations describing dependence of the total bacteria number on temperature, salinity and water saturation with oxygen have been calculated. These results allow to characterize more completely the regularities of eutrophication processes on the Black Sea shelf. PMID:14723155

  8. Estimates of bacterioplankton and Synechococcus spp. mortality from nanoflagellate grazing and viral lysis in the subtropical Danshui River estuary

    Science.gov (United States)

    Tsai, An-Yi; Gong, Gwo-Ching; Huang, Yu Wen; Chao, Chien Fu

    2015-02-01

    To better understand picoplankton dynamics in the surface waters of upriver the Danshui River and its estuary, we assessed nanoflagellate-induced and virus-induced mortality of bacteria and Synechococcus spp. during different seasons (October, 2012 and January, April and July, 2013) using a modified dilution technique. Bacteria and viruses were significantly higher in abundance upriver than at the estuary. The distribution of Synechococcus spp. did not follow this spatial pattern. Abundance of Synechococcus spp. was relatively low during the whole sampling period in the upriver region. Furthermore, bacterial mortality resulting from nanoflagellate grazing were generally higher than those resulting from viral lysis in the upriver region, while Synechococcus spp. losses appeared to be mainly due to viral lysis upriver and in the estuary. Our dilution experiments suggested that nanoflagellates largely depend on bacteria as an important energy source there.

  9. Comparison of Growth Rates of Aerobic Anoxygenic Phototrophic Bacteria and Other Bacterioplankton Groups in Coastal Mediterranean Waters

    Czech Academy of Sciences Publication Activity Database

    Ferrera, I.; Gasol, J.M.; Sebastian, M.; Hojerová, Eva; Koblížek, Michal

    2011-01-01

    Roč. 77, č. 21 (2011), s. 7451-7458. ISSN 0099-2240 R&D Projects: GA ČR GAP501/10/0221 Institutional research plan: CEZ:AV0Z50200510 Keywords : CATALYZED REPORTER DEPOSITION * NATURAL AQUATIC SYSTEMS * IN-SITU HYBRIDIZATION Subject RIV: EE - Microbiology, Virology Impact factor: 3.829, year: 2011

  10. QUANTIFICATION OF RECA GENE EXPRESSION AS AN INDICATOR OF REPAIR POTENTIAL IN MARINE BACTERIOPLANKTON COMMUNITIES OF ANTARCTICA.

    Science.gov (United States)

    Marine bacteria in surface waters must cope daily with the damaging effects of exposure to solar radiation (containing both UV-A and UV-B wavelengths), which produces lesions in their DNA. As the stratospheric ozone layer is depleted, these coping mechanisms are likely to play an...

  11. Effects of resource availability and bacterivory on leucine incorporation in different groups of freshwater bacterioplankton, assessed using microautoradiography

    Czech Academy of Sciences Publication Activity Database

    Horňák, Karel; Jezbera, Jan; Nedoma, Jiří; Gasol, J.M.; Šimek, Karel

    2006-01-01

    Roč. 45, č. 3 (2006), s. 277-289. ISSN 0948-3055 R&D Projects: GA ČR GA206/05/0007 Grant ostatní: FRVŠ(CZ) 1062/2004 Institutional research plan: CEZ:AV0Z60170517 Keywords : leucine incorporation * bacterial structure * bacterial function Subject RIV: EH - Ecology, Behaviour Impact factor: 2.209, year: 2006

  12. Distribution and production of plankton communities in the subtropical convergence zone of the Sargasso Sea. I. Phytoplankton and bacterioplankton

    DEFF Research Database (Denmark)

    Riemann, Lasse; Nielsen, Torkel Gissel; Kragh, Theis;

    2011-01-01

    Elevated levels of biomass and productivity are often associated with ocean frontal systems. The Subtropical Convergence Zone (STCZ) in the southern Sargasso Sea shows pronounced and stable thermal fronts, but little is known about the ecological consequences of these hydrographic features. With...

  13. Genome sequence of the bacterioplanktonic, mixotrophic Vibrio campbellii strain PEL22A, isolated in the Abrolhos Bank.

    Science.gov (United States)

    Amaral, Gilda Rose S; Silva, Bruno Sergio de O; Santos, Eidy O; Dias, Graciela M; Lopes, Rubens M; Edwards, Robert A; Thompson, Cristiane C; Thompson, Fabiano L

    2012-05-01

    Vibrio campbellii PEL22A was isolated from open ocean water in the Abrolhos Bank. The genome of PEL22A consists of 6,788,038 bp (the GC content is 45%). The number of coding sequences (CDS) is 6,359, as determined according to the Rapid Annotation using Subsystem Technology (RAST) server. The number of ribosomal genes is 80, of which 68 are tRNAs and 12 are rRNAs. V. campbellii PEL22A contains genes related to virulence and fitness, including a complete proteorhodopsin cluster, complete type II and III secretion systems, incomplete type I, IV, and VI secretion systems, a hemolysin, and CTXΦ. PMID:22535939

  14. Genome Sequence of the Bacterioplanktonic, Mixotrophic Vibrio campbellii Strain PEL22A, Isolated in the Abrolhos Bank

    OpenAIRE

    Amaral, Gilda Rose S.; Silva, Bruno Sergio de O.; Santos, Eidy O.; Dias, Graciela M.; Rubens M. Lopes; Edwards, Robert A.; Thompson, Cristiane C; Thompson, Fabiano L

    2012-01-01

    Vibrio campbellii PEL22A was isolated from open ocean water in the Abrolhos Bank. The genome of PEL22A consists of 6,788,038 bp (the GC content is 45%). The number of coding sequences (CDS) is 6,359, as determined according to the Rapid Annotation using Subsystem Technology (RAST) server. The number of ribosomal genes is 80, of which 68 are tRNAs and 12 are rRNAs. V. campbellii PEL22A contains genes related to virulence and fitness, including a complete proteorhodopsin cluster, complete type ...

  15. Regulation of bacterioplankton activity in Fram Strait (Arctic Ocean) during early summer: The role of organic matter supply and temperature

    Science.gov (United States)

    Piontek, Judith; Sperling, Martin; Nöthig, Eva-Maria; Engel, Anja

    2014-04-01

    The bacterial turnover of organic matter was investigated in Fram Strait at 79°N. Both Atlantic Water (AW) inflow and exported Polar Water (PW) were sampled along a transect from Spitsbergen to the eastern Greenland shelf during a late successional stage of the main annual phytoplankton bloom in summer. AW showed higher concentrations of amino acids than PW, while organic matter in PW was enriched in combined carbohydrates. Bacterial growth and degradation activity in AW and PW were related to compositional differences of organic matter. Bacterial production and leucine-aminopeptidase along the transect were significantly correlated with concentrations of amino acids. Activity ratios between the extracellular enzymes β-glucosidase and leucine-aminopeptidase indicate the hydrolysis potential for polysaccharides relative to proteins. Along the transect, these ratios showed a higher hydrolysis potential for polysaccharides relative to proteins in PW than in AW, thus reflecting the differences in organic matter composition between the water masses. Q10 values for bacterial production ranged from 2.4 (± 0.8) to 6.0 (± 6.8), while those for extracellular enzymes showed a broader range of 1.5 (± 0.5) to 23.3 (± 11.8). Our results show that in addition to low seawater temperature also organic matter availability contributes to the regulation of bacterial growth and enzymatic activity in the Arctic Ocean.

  16. Biomass, production, and control of heterotrophic bacterioplankton during a late phytoplankton bloom in the Amundsen Sea Polynya, Antarctica

    Science.gov (United States)

    Hyun, Jung-Ho; Kim, Sung-Han; Yang, Eun Jin; Choi, Ayeon; Lee, Sang Hoon

    2016-01-01

    We investigated the heterotrophic bacterial biomass and production in February 2012, in four habitats (a polynya, sea-ice zone, ice shelf, and the open sea) in the Amundsen Sea to determine the spatial distribution, controlling factors, and ecological role of the bacteria during a late phytoplankton bloom by Phaeocystis antarctica. Bacterial abundance (BA) and production (BP) were highest at the center of the polynya, and both were significantly correlated with phytoplankton biomass. BP accounted for average 17% of the organic carbon produced by phytoplankton primary production (PP), which is higher than the average BP:PP ratio reported in most open ocean. The abundance of heterotrophic nanoflagellates (HNF) was correlated with the BA, and the average bacteria:HNF ratio (260) was lower than the values reported in most marine environments (400-1000), including the Ross Sea Polynya (800). Evidence for a tight coupling of bacteria and phytoplankton activities on the one hand and intense HNF grazing on bacteria on the other could be found in the high BP:PP and low bacteria:HNF ratios, respectively. Interestingly, these data were accompanied by low particulate carbon export fluxes measured during the late Phaeocystis bloom. Together, these results indicated that the microbial loop plays a significant role in the biogeochemical carbon cycle and food web processes in the Amundsen Sea Polynya.

  17. Offshore distribution patterns of the cyanobacterium Trichodesmium erythraeum ehrenberg and associated phyto- and bacterioplankton in the southern Atlantic coast (Paraná, Brazil)

    OpenAIRE

    Adriana de Siqueira; Hedda Elisabeth Kolm; Frederico Pereira Brandini

    2006-01-01

    Studies were carried out on Thrichodesmium erythraeum occurring on the inner shelf in the state of Paraná, Brazil. Temperature, salinity, rainfall, wind velocity, total bacteria, bacterial biomass, chlorophyll-a, phytoplankton, Anabaena sp., Merismopedia sp. and T. erythraeum densities were measured in surface water. Centric and pennate diatoms, Anabaena sp. and Merismopedia sp. were most abundant at 15 m isobath, while dinoflagellate abundance was relatively constant among stations. Similarl...

  18. Offshore distribution patterns of the cyanobacterium Trichodesmium erythraeum ehrenberg and associated phyto- and bacterioplankton in the southern Atlantic coast (Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Siqueira Adriana

    2006-01-01

    Full Text Available Studies were carried out on Thrichodesmium erythraeum occurring on the inner shelf in the state of Paraná, Brazil. Temperature, salinity, rainfall, wind velocity, total bacteria, bacterial biomass, chlorophyll-a, phytoplankton, Anabaena sp., Merismopedia sp. and T. erythraeum densities were measured in surface water. Centric and pennate diatoms, Anabaena sp. and Merismopedia sp. were most abundant at 15 m isobath, while dinoflagellate abundance was relatively constant among stations. Similarly, total bacterial densities were relatively homogeneous throughout the sampling area, suggesting that blooms of T. erythraeum were not yet in the senescent phase. Results showed that T. erythraeum was capable of surviving in relatively inhospitable environmental conditions, due to its ability to fix nitrogen and to photosynthesis at high light intensities.

  19. Chloroflexi CL500-11 Populations That Predominate Deep-Lake Hypolimnion Bacterioplankton Rely on Nitrogen-Rich Dissolved Organic Matter Metabolism and C1 Compound Oxidation.

    Science.gov (United States)

    Denef, Vincent J; Mueller, Ryan S; Chiang, Edna; Liebig, James R; Vanderploeg, Henry A

    2016-03-01

    The Chloroflexi CL500-11 clade contributes a large proportion of the bacterial biomass in the oxygenated hypolimnia of deep lakes worldwide, including the world's largest freshwater system, the Laurentian Great Lakes. Traits that allow CL500-11 to thrive and its biogeochemical role in these environments are currently unknown. Here, we found that a CL500-11 population was present mostly in offshore waters along a transect in ultraoligotrophic Lake Michigan (a Laurentian Great Lake). It occurred throughout the water column in spring and only in the hypolimnion during summer stratification, contributing up to 18.1% of all cells. Genome reconstruction from metagenomic data suggested an aerobic, motile, heterotrophic lifestyle, with additional energy being gained through carboxidovory and methylovory. Comparisons to other available streamlined freshwater genomes revealed that the CL500-11 genome contained a disproportionate number of cell wall/capsule biosynthesis genes and the most diverse spectrum of genes involved in the uptake of dissolved organic matter (DOM) substrates, particularly peptides. In situ expression patterns indicated the importance of DOM uptake and protein/peptide turnover, as well as type I and type II carbon monoxide dehydrogenase and flagellar motility. Its location in the water column influenced its gene expression patterns the most. We observed increased bacteriorhodopsin gene expression and a response to oxidative stress in surface waters compared to its response in deep waters. While CL500-11 carries multiple adaptations to an oligotrophic lifestyle, its investment in motility, its large cell size, and its distribution in both oligotrophic and mesotrophic lakes indicate its ability to thrive under conditions where resources are more plentiful. Our data indicate that CL500-11 plays an important role in nitrogen-rich DOM mineralization in the extensive deep-lake hypolimnion habitat. PMID:26682860

  20. Productivity cycles in the coastal upwelling area off Concepción: The importance of diatoms and bacterioplankton in the organic carbon flux

    Science.gov (United States)

    Montero, Paulina; Daneri, Giovanni; Cuevas, L. Antonio; González, Humberto E.; Jacob, Bárbara; Lizárraga, Lorena; Menschel, Eduardo

    2007-11-01

    Recurrent coastal upwelling is recognized as one of the main factors promoting the exceptionally high productivity of the Humboldt Current System. Herein, we study time series data of gross primary production (2003-2006) and its fluctuation in relation to seasonal changes in the light and nutrient field of the Concepción upwelling ecosystem. Concurrent measurements of gross primary production, community respiration, bacterial secondary production, and sedimentation rates allowed a characterization of the main carbon fluxes and pathways in the study area. The integrated values of gross primary production were higher during the upwelling period (>1 g C m -2 d -1; October-April; that is, early spring to early austral fall). Seasonal changes in the system were also reflected in community respiration, organic matter sedimentation, and bacterial production rates, which varied along with the gross primary production. The significant correlation between gross primary production and community respiration (Spearman, r = 0.7; p 6 g C m -2 d -1) were consistently associated with maximum biomass levels of Skeletonema costatum and Thalassiosira subtilis. We observed a positive correlation between gross primary production and the sedimentation of intact diatom cells (Spearman, r = 0.5, p < 0.05, n = 17). Our data suggest that, in the Concepción upwelling ecosystem, bacteria utilize an important fraction of the gross primary production. If our interpretations are correct, they leave unanswered the question of how the system supports the extremely high fish biomass levels, therein pointing out the system’s limited capacity to buffer the evasion of CO 2 following upwelling.

  1. ACTIVITIES OF AMMONIA ASSIMILATION ENZYMES AS INDICATORS OF THE RELATIVE SUPPLY OF NITROGEN SUBSTRATES FOR MARINE BACTERIOPLANKTON IN SUB-TROPICAL COASTAL WATER

    Science.gov (United States)

    The supply of nitrogen substrates available for bacterial production in seawater was determined using the activities of ammonia assimilation enzymes, glutamine synthetase (GS) and glutamate dehydrogenase (GDH). Expression of GS and GDH by bacteria in pure culture is generally ind...

  2. Bacterioplankton Production in Humic Lake Örträsket in Relation to Input of Bacterial Cells and Input of Allochthonous Organic Carbon.

    Science.gov (United States)

    Bergström; Jansson

    2000-02-01

    In order to compare riverine bacteria input with lake water bacterial production and grazing loss with output loss, a bacterial cell budget was constructed for humic Lake Örträsket in northern Sweden. The riverine input of bacterial cells in 1997 represented 29% of the number of bacterial cells produced within the layer of the lake affected by inlet water. A large share of the in situ lake bacterial production was consumed by grazers, mainly flagellates, which stresses the importance of bacteria as energy mobilizers for the pelagic food web in the lake. The bacterial production in Lake Örträsket, which is almost entirely dependent on humic material as an energy source, was clearly stimulated by high flow episodes which brought high amounts of little degraded material into the lake. During base flow condition the bacterial production in the inlet rivers was high, which led to an input of more degraded material to the lake. This material did not stimulate the lake bacterial production. Internal factors that determined the utilization of the allochthonous DOC in the lake were the retention time and the exposure to light and high temperatures. Thus, the potential for in situ production of bacteria in Lake Örträsket was to a large extent a function of how precipitation and runoff conditions affected terrestrial losses and river transport of humic material. PMID:10833223

  3. Impact of water quality on bacterioplankton assemblage along Cértima River Basin (central western Portugal) assessed by PCR-DGGE and multivariate analysis.

    Science.gov (United States)

    de Figueiredo, Daniela R; Ferreira, Raquel V; Cerqueira, Mário; de Melo, Teresa Condesso; Pereira, Mário J; Castro, Bruno B; Correia, António

    2012-01-01

    The information on bacterial community composition (BCC) in Portuguese water bodies is very scarce. Cértima River (central western Portugal) is known to have high levels of pollution, namely organic. In the present work, the BCC from a set of 16 water samples collected from Cértima River Basin and its main tributaries was characterized using 16S rDNA-denaturing gradient gel electrophoresis, a culture-independent molecular approach. Molecular data were related to environmental parameters through multivariate analysis to investigate potential impact of water pollution along the river. Principal component analysis using environmental data showed a water quality gradient from more pristine waters (at the mountain tributaries) to waters with increasingly eutrophic potential (such as Fermentelos Lake). This gradient was mainly defined by factors such as organic and inorganic nutrient sources, electrical conductivity, hydrogen carbonate concentration, and pH. Molecular results showed variations in BCC along Cértima River Basin but in the main river section, a Bacteroidetes phylotype (Flavobacterium sp.) proved to be dominant throughout the river course. Multivariate analysis suggests that spatial variation of BCC along the Cértima River Basin depended mainly on parameters such as Chl a, total suspended solid (TSS), total organic carbon, electrical conductivity, and HCO[Formula: see text] levels. Bacteroidetes phylotypes were all related to higher electrical conductivity and HCO[Formula: see text] levels although some of these were also correlated with high SO[Formula: see text] and others with high soluble reactive phosphorus, nitrate, TN, and Kjeld-N levels. The Gammaproteobacteria occurrence was correlated with high SO[Formula: see text] levels. One of the Betaproteobacteria phylotypes showed to correlate with low redox potential (E(h)) and high temperature, pH, TSS, and Chl a levels while another one showed a negative correlation with Chl a values. PMID:21431313

  4. Influence of top-down and bottom-up manipulations on the R-BT065 subcluster of Betaproteobacteria, an abundant group in bacterioplankton of a freshwater reservoir

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Horňák, Karel; Jezbera, Jan; Mašín, Michal; Nedoma, Jiří; Gasol, J. M. .; Schauer, M.

    2005-01-01

    Roč. 71, č. 5 (2005), s. 2381-2390. ISSN 0099-2240 R&D Projects: GA ČR(CZ) GA206/05/0007; GA ČR(CZ) GA206/02/0003 Grant ostatní: CSIC(ES) DGICYT REN2001-2120/MAR; EU(XE) EVK3-CT-2002-00078; Austrian Science Foundation(AT) P15655 Institutional research plan: CEZ:AV0Z60170517 Keywords : reservoir * top-down and bottom-up control * microbial food webs * bacterivory * bacterial community composition Subject RIV: EE - Microbiology, Virology Impact factor: 3.818, year: 2005

  5. Influence of freshwater discharge on the microbial degradation processes of dissolved organic nitrogen in a subtropical estuary.

    Science.gov (United States)

    Garcia, Juan C; Ketover, Rheannon D J; Loh, Ai Ning; Parsons, Michael L; Urakawa, Hidetoshi

    2015-02-01

    River bacterioplankton communities, influenced by watershed usage, are responsible for water purification. Bacterioplankton may be critical in the degradation of dissolved organic nitrogen (DON), the major nitrogen pool in the Caloosahatchee River, Florida. We investigated how freshwater discharge influences estuarine bacterioplankton and how the freshwater-originated DON is utilized by estuarine bacterioplankton. Microcosm experiments were conducted during low and high discharge using two upstream freshwater samples: one site primarily influenced by Lake Okeechobee and the other site moderately influenced by an agricultural watershed. These freshwater samples were filtered to eliminate indigenous microbial populations, then mixed with estuarine bacterioplankton. High-throughput sequencing revealed that bacterioplankton differed between low and high discharge and were influenced by salinity. Alphaproteobacteria and Bacteroidetes dominated in low discharge while Bacteroidetes and Cyanobacteria dominated during high discharge. In the microcosm experiment, DON concentration decreased with increasing cell densities, suggesting that the DON was utilized as a carbon and nitrogen source. Band signals in denaturing gradient gel electrophoresis corresponding to Alphaproteobacteria and Actinobacteria decreased while Gammaproteobacteria increased during the 1 month incubation. This data suggests that estuarine bacterioplankton communities are influenced by variations in discharge patterns and use freshwater-originated DON as demonstrated by a shift in community structure. PMID:25542211

  6. Investigation of the planktonic organism state in the upper and lower pools of hydroelectric stations on the Vuoksa River

    International Nuclear Information System (INIS)

    The main branch of the upstream stretch of the Vuoksa River was studied in order to determine the effects of the Svetogorskaya and Lesogorskaya hydroelectric stations on plankton (phyto-, zoo-, and bacterioplankton). The average loss of plankton (phyto- and zooplankton) due to passage through the hydroelectric station turbine does not exceed 35% and depends on the season of the year. No cavitation effect on bacterioplankton was found. It was revealed that a far more negative effect on the Vuoksa River plankton, particularly zoo- and bacterioplankton, was due to pollution of the river water with industrial sewage from the pulp-and-paper mill located downstream from the Svetogorskaya Hydropower Plant

  7. Sources of carbon and sulfur nutrition for consumers in three meromictic lakes of New York State

    Science.gov (United States)

    Fry, B.; Hayes, J. M. (Principal Investigator)

    1986-01-01

    The trophic importance of bacterioplankton as a source of carbon and sulfur nutrition for consumers in meromictic lakes was tested using stable carbon (delta 13C) and sulfur (delta 34S) isotopic measurements. Studies in three lakes near Syracuse, New York, showed that most consumers ultimately derive their C and S nutrition from a mixture of terrestrial detritus, phytoplankton, and littoral vegetation, rather than from bacterioplankton. Food webs in these meromictic lakes are thus similar to those in other lakes that lack dense populations of bacterioplankton.

  8. Diversity and Phylogenetic Affiliations of Morphologically Conspicuous Large Filamentous Bacteria Occurring in the Pelagic Zones of a Broad Spectrum of Freshwater Habitats

    OpenAIRE

    Schauer, Michael; Hahn, Martin W.

    2005-01-01

    Filamentous bacteria with a conspicuous morphology were found in the majority of the bacterioplankton samples from a variety of freshwater habitats that were studied. These heterotrophic filaments typically account for

  9. The ecology of pelagic freshwater methylotrophs assessed by a high-resolution monitoring and isolation campaign

    Czech Academy of Sciences Publication Activity Database

    Salcher, Michaela M.; Neuenschwander, S. M.; Posch, T.; Pernthaler, J.

    2015-01-01

    Roč. 9, č. 11 (2015), s. 2442-2453. ISSN 1751-7362 Institutional support: RVO:60077344 Keywords : in-situ hybridization * genome sequence * bacterioplankton populations Subject RIV: EE - Microbiology, Virology Impact factor: 9.302, year: 2014

  10. Bacterial growth efficiency in a tropical estuary: Seasonal variability subsidized by allochthonous carbon

    Digital Repository Service at National Institute of Oceanography (India)

    Ram, A.S.P.; Nair, S.; Chandramohan, D.

    through bacteria (>100% of primary productivity) in the estuarine and coastal waters suggests that bacterioplankton consumed dissolved organic carbon in excess of the amount produced in situ by phytoplankton of this region, which led to the mismatch...

  11. The percentage of living bacterial cells related to organic carbon release from senescent oceanic phytoplankton

    OpenAIRE

    S. Lasternas; S. Agustí

    2014-01-01

    Bacteria recycle vast amounts of organic carbon, playing key biogeochemical and ecological roles in the ocean. Bacterioplankton dynamics are expected to be dependent on phytoplankton primary production, but there is a high diversity of processes (e.g., sloppy feeding, cell exudation, viral lysis) involved in the transfer of primary production to dissolved organic carbon available to bacteria. Here, we show the percentage of living heterotrophic bacterioplankton in the subtro...

  12. Phosphorus use by planktonic communities in a large regulated Mediterranean river.

    Science.gov (United States)

    Artigas, J; Soley, S; Pérez-Baliero, M C; Romaní, A M; Ruiz-González, C; Sabater, S

    2012-06-01

    The regulation of large rivers to meet human requirements (e.g. hydroelectricity production, flood prevention, recreation activities) alters the longitudinal distribution of plankton communities and may affect their capacity to use nutrients and organic matter. Here we analyzed phosphorus (P) availability and use by phytoplankton and bacterioplankton in 6 upstream and 5 downstream sites from a reservoir system in the Ebro River (N Spain). Alkaline phosphatase activity (APA) was related to nutrient availability and biomass of both phytoplankton and bacterioplankton. During dry periods phytoplankton and bacterioplankton APA was inversely correlated to P availability in the water, but these patterns became less clear during wet periods. The phosphorus-APA patterns were more consistent in the upstream sites and especially during dry periods. Although phytoplankton APA was 6-40 times greater than that of bacterioplankton, APA per unit of biomass suggested that bacterioplankton was more efficient at utilizing dissolved organic phosphorus (DOP) in the upstream section during dry periods. Imbalanced N:P ratios in the particulate (N:P ranging 133-170) and dissolved (N:P ranging 301-819) water fractions confirmed the strong P limitation in these upstream communities. The phosphorus-APA patterns were weaker in the downstream section and during wet periods. The reservoirs caused a change in the downstream dynamics, where bacterioplankton biomass was positively correlated to APA but APA per unit of biomass decreased. Our findings reveal that river regulation drives changes in plankton use of organic phosphorus, especially during extreme dry periods. PMID:22503678

  13. Differential response of high-elevation planktonic bacterial community structure and metabolism to experimental nutrient enrichment.

    Directory of Open Access Journals (Sweden)

    Craig E Nelson

    Full Text Available Nutrient enrichment of high-elevation freshwater ecosystems by atmospheric deposition is increasing worldwide, and bacteria are a key conduit for the metabolism of organic matter in these oligotrophic environments. We conducted two distinct in situ microcosm experiments in a high-elevation lake (Emerald Lake, Sierra Nevada, California, USA to evaluate responses in bacterioplankton growth, carbon utilization, and community structure to short-term enrichment by nitrate and phosphate. The first experiment, conducted just following ice-off, employed dark dilution culture to directly assess the impact of nutrients on bacterioplankton growth and consumption of terrigenous dissolved organic matter during snowmelt. The second experiment, conducted in transparent microcosms during autumn overturn, examined how bacterioplankton in unmanipulated microbial communities responded to nutrients concomitant with increasing phytoplankton-derived organic matter. In both experiments, phosphate enrichment (but not nitrate caused significant increases in bacterioplankton growth, changed particulate organic stoichiometry, and induced shifts in bacterial community composition, including consistent declines in the relative abundance of Actinobacteria. The dark dilution culture showed a significant increase in dissolved organic carbon removal in response to phosphate enrichment. In transparent microcosms nutrient enrichment had no effect on concentrations of chlorophyll, carbon, or the fluorescence characteristics of dissolved organic matter, suggesting that bacterioplankton responses were independent of phytoplankton responses. These results demonstrate that bacterioplankton communities in unproductive high-elevation habitats can rapidly alter their taxonomic composition and metabolism in response to short-term phosphate enrichment. Our results reinforce the key role that phosphorus plays in oligotrophic lake ecosystems, clarify the nature of bacterioplankton nutrient

  14. Relación entre la abundancia y biomasa de fitoplancton y bacterioplancton heterotrófico en aguas superficiales del Golfo de Arauco, Chile Relation between count and biomass of phytoplankton and heterotrophic bacterioplankton in superficial water of Arauco Gulf, Chile

    Directory of Open Access Journals (Sweden)

    Mireya Abarzúa R

    1995-01-01

    Full Text Available Se analiza la relación entre la abundancia (concentración de células y biomasa fitoplanctónica con la bacteriana, en la zona adyacente a la desembocadura del río Bío-Bío en el Golfo de Arauco, Chile. Para estimar la abundancia y biomasa bacteriana total, de bacterias heterótrofas aeróbicas recuperables y del fitoplancton, se realizaron muestreos en marzo (verano y agosto (invierno de 1991. Los resultados indican que la abundancia del fitoplancton presenta una correlación significativa con la abundancia y biomasa de bacterias heterotróficas, a diferencia de lo que ocurre con las mismas variables del total de bacterias. Se encontró una alta correlación de la abundancia de algas fitoplanctónicas y bacterias heterotróficas con la temperatura, parámetro que explica un alto porcentaje de las variaciones temporales observadasThis work analize the relationships between the standing crop and biomass of phytoplankton and bacteria in the zone of the Arauco Gulf, Chile. Samples were taken during the month of march (summer and august (winter of 1991. The number and biomass of total bacteria, of aerobic heterotrophic bacteria, and of the phytoplankton were studied. The results show that the number of phytoplankton has a positive correlation with the number and biomass of the heterotrophic bacteria, but not with the total bacteria. There is also a high correlation with temperature, justifying the temporal variations noted in the results

  15. [Heterotrophic organisms and viruses in the Oka River and Cheboksary Reservoir during the abnormally hot summer of 2010].

    Science.gov (United States)

    Kopylov, A I; Stroĭnov, Ia V; Zabotkina, E A; Romanenko, A V; Maslennikova, T S

    2013-01-01

    In July 2010, abnormally high water temperature (25-29 degrees C), as well as increased biomass and phytoplankton production caused intensive development of heterotrophic bacteria and heterotrophic nanoflagellates. It was found that the abundance, biomass, and production of heterotrophic bacterioplankton, as well as the abundance and biomass of heterotrophic nanoflagellates, and the number of planktonic viruses, which were calculated on average for the reservoir under study, turned out to be higher in the years with lower water temperature (20-23 degrees C). The virus-induced mortality of bacterioplankton in the Oka River and the Cheboksary Reservoir averaged 25.4 +/- 3.4 and 22.4 +/- 2.7% of the daily bacterioplankton production. PMID:24171319

  16. Autotrophic and heterotrophic abundance and activity associated with a nearshore front off the Georgia coast, U.S.A.

    Science.gov (United States)

    Jacobsen, T. R.; Pomeroy, L. R.; Blanton, J. O.

    1983-11-01

    The nearshore frontal zone off the coast of Georgia was found to be an area of high phytoplankton and bacterioplankton abundance and activity. Phytoplankton and bacterioplankton populations on the seaward side of the frontal zone had significantly higher photosynthetic and heterotrophic potentials than the nearshore side of the front. Phytoplankton species composition changed across the front, verifying that the front is a barrier to cross shelf mixing. Nearshore, large chain forming diatoms dominated, while smaller single cell diatoms and cyanobacteria dominated the seaward side of the front. Increased bacterioplankton activity was found associated with phytoplankton photosynthetic activity. Light appeared to be the major factor controlling photosynthesis across the frontal zone. Nitrogen, phosphorus and silica were present in similar concentrations, well above levels that would limit photosynthesis, on both sides of the front. Therefore the outflow of nutrients from rivers or estuaries did not influence primary production directly.

  17. Final Technical Report: DOE-Biological Ocean Margins Program. Microbial Ecology of Denitrifying Bacteria in the Coastal Ocean.

    Energy Technology Data Exchange (ETDEWEB)

    Lee Kerkhof

    2013-01-01

    The focus of our research was to provide a comprehensive study of the bacterioplankton populations off the coast of New Jersey near the Rutgers University marine field station using terminal restriction fragment polymorphism analysis (TRFLP) coupled to 16S rRNA genes for large data set studies. Our three revised objectives to this study became: (1) to describe bacterioplankton population dynamics in the Mid Atlantic Bight using TRFLP analysis of 16S rRNA genes. (2) to determine whether spatial and temporal factors are driving bacterioplankton community dynamics in the MAB using monthly samping along our transect line over a 2-year period. (3) to identify dominant members of a coastal bacterioplankton population by clonal library analysis of 16S rDNA genes and sequencing of PCR product corresponding to specific TRFLP peaks in the data set. Although open ocean time-series sites have been areas of microbial research for years, relatively little was known about the population dynamics of bacterioplankton communities in the coastal ocean on kilometer spatial and seasonal temporal scales. To gain a better understanding of microbial community variability, monthly samples of bacterial biomass were collected in 1995-1996 along a 34-km transect near the Long-Term Ecosystem Observatory (LEO-15) off the New Jersey coast. Surface and bottom sampling was performed at seven stations along a transect line with depths ranging from 1 to 35m (n=178). The data revealed distinct temporal patterns among the bacterioplankton communities in the Mid-Atlantic Bight rather than grouping by sample location or depth (figure 2-next page). Principal components analysis models supported the temporal patterns. In addition, partial least squares regression modeling could not discern a significant correlation from traditional oceanographic physical and phytoplankton nutrient parameters on overall bacterial community variability patterns at LEO-15. These results suggest factors not traditionally

  18. Bacteria and viruses of the ice-free aquatic area of the Barents Sea at the beginning of polar night.

    Science.gov (United States)

    Shirokolobova, T I; Zhichkin, A P; Venger, M P; Vodopyanova, V V; Moiseev, D V

    2016-07-01

    The most massive components of the microplankton were studied in the open sea waters for the first time at the end of the autumn season. It has been found that abundance of the virio- and bacterioplankton exceeded that observed in winter in the coastal zone. Against the background of a relatively uniform distribution of bacteria, the viral abundance and the lysis-mediated bacterioplankton death rate reached the maximum values in the most cold and salty waters of the northern sea areas. PMID:27595827

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

    Czech Academy of Sciences Publication Activity Database

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

    2011-01-01

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

  20. Ecosystem characterization in Indian Ocean sector, Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Matondkar, S.G.P.; Dhargalkar, V.K.; Parulekar, A.H.

    and picoheterotrophs in food chain. The bacterioplankton equals the zooplankton biomass, at second trophic level. The zooplankton biomass recorded was 100 g/1000 m sup(3) , 50 g/1000 m sup(3) being krill. The 50% of zooplankton were copepods alone. Its relation...

  1. Influence of filtration and glucose amendment on bacterial growth rate at different tidal conditions in the Minho Estuary River (NW Portugal)

    DEFF Research Database (Denmark)

    Anne, I.; Fidalgo, M. L.; Thosthrup, L.;

    2006-01-01

    Bacterioplankton abundance, biomass and growth rates were studied in the Minho Estuary River (NW Portugal). The influence of tidal conditions, glucose amendment, and the filtration process on total bacterial abundance, total and faecal coliforms, as well as faecal streptococci, were evaluated in...

  2. Abundance of broad bacterial Taxa in the Sargasso Sea explained by environmental conditions but not water mass

    DEFF Research Database (Denmark)

    Sjöstedt, Johanna; Martiny, Jennifer Bellanca Hughes; Munk, Peter; Riemann, Lasse

    2014-01-01

    To explore the potential linkage between distribution of marine bacterioplankton groups, environmental conditions, and water mass, we investigated the factors determining the abundance of bacterial taxa across the hydrographically complex Subtropical Convergence Zone in the Sargasso Sea. Based on...... Sargasso Sea using only a few environmental parameters....

  3. TURNOVER OF EXTRACELLULAR DNA IN EUTROPHIC AND OLIGOTROPHIC FRESHWATER ENVIRONMENTS OF SOUTHWEST FLORIDA

    Science.gov (United States)

    Turnover oF extracellular DNA was investigated in oligotrophic springs of the Crystal River and the eutrophic Medard Reservoir of southwest Florida. he Medard Reservoir possessed large populations of bacterioplankton and phytoplankton (6.8 x l0-9 cells per liter and 28.6 ug of ch...

  4. Impacts of the Three Gorges Dam on microbial structure and potential function.

    Science.gov (United States)

    Yan, Qingyun; Bi, Yonghong; Deng, Ye; He, Zhili; Wu, Liyou; Van Nostrand, Joy D; Shi, Zhou; Li, Jinjin; Wang, Xi; Hu, Zhengyu; Yu, Yuhe; Zhou, Jizhong

    2015-01-01

    The Three Gorges Dam has significantly altered ecological and environmental conditions within the reservoir region, but how these changes affect bacterioplankton structure and function is unknown. Here, three widely accepted metagenomic tools were employed to study the impact of damming on the bacterioplankton community in the Xiangxi River. Our results indicated that bacterioplankton communities were both taxonomically and functionally different between backwater and riverine sites, which represent communities with and without direct dam effects, respectively. There were many more nitrogen cycling Betaproteobacteria (e.g., Limnohabitans), and a higher abundance of functional genes and KEGG orthology (KO) groups involved in nitrogen cycling in the riverine sites, suggesting a higher level of bacterial activity involved in generating more nitrogenous nutrients for the growth of phytoplankton. Additionally, the KO categories involved in carbon and sulfur metabolism, as well as most of the detected functional genes also showed clear backwater and riverine patterns. As expected, these diversity patterns all significantly correlated with environmental characteristics, confirming that the bacterioplankton communities in the Xiangxi River were really affected by environmental changes from the Three Gorges Dam. This study provides a first comparative metagenomic insight for evaluating the impacts of the large dam on microbial function. PMID:25721383

  5. Microbial biogeography along an estuarine salinity gradient: combined influences of bacterial growth and residence time.

    Science.gov (United States)

    Crump, Byron C; Hopkinson, Charles S; Sogin, Mitchell L; Hobbie, John E

    2004-03-01

    Shifts in bacterioplankton community composition along the salinity gradient of the Parker River estuary and Plum Island Sound, in northeastern Massachusetts, were related to residence time and bacterial community doubling time in spring, summer, and fall seasons. Bacterial community composition was characterized with denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA. Average community doubling time was calculated from bacterial production ([(14)C]leucine incorporation) and bacterial abundance (direct counts). Freshwater and marine populations advected into the estuary represented a large fraction of the bacterioplankton community in all seasons. However, a unique estuarine community formed at intermediate salinities in summer and fall, when average doubling time was much shorter than water residence time, but not in spring, when doubling time was similar to residence time. Sequencing of DNA in DGGE bands demonstrated that most bands represented single phylotypes and that matching bands from different samples represented identical phylotypes. Most river and coastal ocean bacterioplankton were members of common freshwater and marine phylogenetic clusters within the phyla Proteobacteria, Bacteroidetes, and ACTINOBACTERIA: Estuarine bacterioplankton also belonged to these phyla but were related to clones and isolates from several different environments, including marine water columns, freshwater sediments, and soil. PMID:15006771

  6. Seasonal dynamics of SAR11 populations in the euphotic and mesopelagic zones of the northwestern Sargasso Sea

    DEFF Research Database (Denmark)

    Carlson, Craig A; Morris, Robert; Parsons, Rachel;

    2009-01-01

    Bacterioplankton belonging to the SAR11 clade of a-proteobacteria were counted by fluorescence in situ hybridization (FISH) over eight depths in the surface 300 m at the Bermuda Atlantic Time-series Study (BATS) site from 2003 to 2005. SAR11 are dominant heterotrophs in oligotrophic systems; thus...

  7. Insights into variability of actinorhodopsin genes of the LG1 cluster in two different freshwater habitats

    Czech Academy of Sciences Publication Activity Database

    Jezberová, Jitka; Jezbera, Jan; Hahn, M.W.

    2013-01-01

    Roč. 8, č. 7 (2013), e68542. E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GEEEF/10/E011 Institutional support: RVO:60077344 Keywords : actinobacteria * bacteria * bacterioplankton * diversity * sequences * lakes Subject RIV: EE - Microbiology, Virology Impact factor: 3.534, year: 2013

  8. [Relationships between the Biomass and Production of Bacterio- and Phytoplanktonic Communities].

    Science.gov (United States)

    Aponasenko, A D; Shchur, L A

    2016-01-01

    Quantitative ratios of the biomasses of bacterio- and phytoplankton, interrelation of their production characteristics, and association of the functional characteristics with environmental factors were studied for Lake Khanka, the Yenisei River and the Krasnoyarsk Reservoir. The ratio between the biomasses of bacterioplankton (Bb) and phytoplankton (Bp) in these water bodies was shown to vary within the range exceeding three orders of magnitude. Bacterioplankton biomass was relatively stable and varied from sample to sample by an order of magnitude. In more than 50% of the samples (total sample number, 495), bacterioplankton biomass exceeded that of the phytoplankton. The average Bb/Bp ratios for Lake Khanka, Yenisei River, and Krasnoyarsk Reservoir were 5.1, 2, and 1.4, respectively. Increased Bb/Bp ratios were found to correlate with elevated specific (per unit biomass) phytoplankton production. This finding indicated additional supply of biogenic elements to phytoplankton due to their recycling by bacterial communities. The ratio between bacterioplankton and phytoplankton production for Lake Khanka varied from year to year (0.07 to 0.76). For the Yenisei River and the Krasnoyarsk Reservoir these ratios were on average 0.19 and 0.27, respectively. According to the literature data for other water bodies, bacterial production may reach from 10 to over 100% of the primary production. The equilibrium density of bacterioplankton (maximal density of the population) in Lake Khanka was ~1.5 times higher than in the Yenisei River and the Krasnoyarsk Reservoir due to higher content of suspended mineral matter and associated organo-mineral detritus in the lake. The interaction between dissolved organic compounds sorbed of the surface of mineral particles results in chemical alteration of biochemically stable substrate into compounds which may be assimilated by aquatic micoorganisms. PMID:27476209

  9. Bacterial community structure influenced by Coscinodiscus sp. in the Vistula river plume* This research was carried out with the support of a grant from the Polish Ministry of Science and Higher Education (No. NN304 025334 and statutory activities of the Department of Fisheries Oceanography and Marine Ecology of the National Marine Fisheries Research Institute (project P1-2.

    Directory of Open Access Journals (Sweden)

    Anetta Ameryk

    2014-01-01

    Full Text Available The Gulf of Gdańsk is influenced by freshwater inflow from the River Vistula and by a wind-driven current along the coast. Bacterial communities from five stations along a salinity gradient were sampled during one day and analysed by terminal restriction fragment length polymorphism (T-RFLP, catalysed reporter deposition-fluorescence in situ hybridisation (CARD-FISH and 16S rRNA gene libraries. On the day of sampling, we observed a probable current-driven seawater influx into the inner part of the gulf that separated the gulf into distinct water bodies. Members of the diatom Coscinodiscus sp. dominated one of these water bodies and influenced the bacterial community. The coexistence of typically freshwater and marine bacterioplankton populations in the Vistula river plume suggested an integration of some freshwater populations into the Baltic Sea bacterioplankton.

  10. Diversity of Bacteroidetes in high altitude saline evaporitic basins in northern Chile

    OpenAIRE

    Dorador, Cristina; Meneses, D.; Urtuvia, V.; Demergasso, C.; Vila, I; Witzel, K.-P.; Imhoff, Johannes F.

    2009-01-01

    The phylum Bacteroidetes represents one of the most abundant bacterial groups of marine and freshwater bacterioplankton. We investigated the diversity of Bacteroidetes in water and sediment samples from three evaporitic basins located in the highlands of northern Chile. We used both 16S rRNA gene clone libraries created with targeted Bacteroidetes-specific primers and separation of specifically amplified gene fragments by denaturing gradient gel electrophoresis (DGGE). DGGE analysis revealed ...

  11. Low Microbial Respiration of Leucine at Ambient Oceanic Concentration in the Mixed Layer of the Central Atlantic Ocean

    Science.gov (United States)

    Hill, P.; Warwick, P.; Zubkov, M.

    2012-12-01

    Bacterioplankton are the primary consumers of dissolved organic matter in the ocean, thus the quantification of bacterioplankton production (BP) is essential to our understanding of carbon cycling in the largest ecosystems on Earth. We compared BP, measured as the rate of 14C-leucine (14C-Leu) or 3H-leucine (3H-Leu) uptake at close to saturating concentration (20 nM), with ambient Leu uptake estimated from dilution bioassays. The latter uses 3H-Leu additions at a range of concentrations close to ambient to estimate ambient Leu uptake rates, in addition to bioavailability and turnover rates. We hypothesised that saturation with Leu would lead to its respiration as a carbon source, thereby not truly representing ambient BP. Seawater samples were collected from the photic zone (22-170 m) in mesotrophic and oligotrophic regions along a transect through the central Atlantic Ocean. Respiration as a proportion of total consumption (uptake + respiration) of close to ambient (0.4 nM) and close to saturating (20 nM) 14C-Leu additions were compared. Leu uptake rates measured using saturating 3H-Leu additions were generally comparable with ambient rates estimated by dilution bioassays; however, saturating additions may overestimate uptake at low rates and underestimate uptake at high rates. The proportion of total Leu uptake that was respired was 3-fold higher for 20 nM 14C-Leu additions than 0.4 nM 14C-Leu additions (15±8% and 5±4%, respectively). Consequently, microbial efficiency of Leu assimilation - an indicator of bacterioplankton growth efficiency - was significantly higher at close to ambient 14C-Leu additions than at close to saturating concentrations (95±4% and 85±8%, respectively). Thus, saturation of open Atlantic Ocean bacterioplankton with Leu, or other molecules indicative of microbial metabolism, leads to the measurement of a response to nutrient addition, rather than an ambient measurement.

  12. Top-down and bottom-up induced shifts in bacterial abundance, production and community composition in an experimentally divided humic lake

    Czech Academy of Sciences Publication Activity Database

    Grossart, H. P.; Jezbera, Jan; Horňák, Karel; Hutalle, K. M. L.; Buck, U.; Šimek, Karel

    2008-01-01

    Roč. 10, č. 3 (2008), s. 635-652. ISSN 1462-2912 R&D Projects: GA ČR(CZ) GA206/05/0007 Institutional research plan: CEZ:AV0Z60170517 Keywords : in situ hybridization * meso- eutrophic reservoir * dissolved organic carbon * fresh-water reservoir * bacterioplankton community * dystrophic lake Subject RIV: EE - Microbiology, Virology Impact factor: 4.707, year: 2008

  13. Picoplankton Community Composition by CARD-FISH and Flow Cytometric Techniques: A Preliminary Study in Central Adriatic Sea Water

    OpenAIRE

    Anita Manti; Paola Boi; Federica Semprucci; Rosaria Cataudella; Stefano Papa

    2012-01-01

    Data concerning picoplanktonic community composition and abundance in the Central Adriatic Sea are presented in an effort to improve the knowledge of bacterioplankton and autotrophic picoplankton and their seasonal changes. Flow cytometry analyses revealed the presence of two distinct bacteria populations: HNA and LNA cells. HNA cells showed an explicit correlation with viable and actively respiring cells. The study of viability and activity may increase our knowledge of the part that con...

  14. Abundance of Broad Bacterial Taxa in the Sargasso Sea Explained by Environmental Conditions but Not Water Mass

    OpenAIRE

    Sjöstedt, Johanna; Martiny, Jennifer B. H.; Munk, Peter; Riemann, Lasse

    2014-01-01

    To explore the potential linkage between distribution of marine bacterioplankton groups, environmental conditions, and water mass, we investigated the factors determining the abundance of bacterial taxa across the hydrographically complex Subtropical Convergence Zone in the Sargasso Sea. Based on information from 16S rRNA gene clone libraries from various locations and two depths, abundances of the predominant taxa (eubacteria, Archaea, Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes,...

  15. Effects of Dispersal and Initial Diversity on the Composition and Functional Performance of Bacterial Communities

    OpenAIRE

    Yinghua Zha; Mercè Berga; Jérôme Comte; Silke Langenheder

    2016-01-01

    Natural communities are open systems and consequently dispersal can play an important role for the diversity, composition and functioning of communities at the local scale. It is, however, still unclear how effects of dispersal differ depending on the initial diversity of local communities. Here we implemented an experiment where we manipulated the initial diversity of natural freshwater bacterioplankton communities using a dilution-to-extinction approach as well as dispersal from a regional ...

  16. A transplant experiment to identify the factors controlling bacterial abundance, activity, production and community composition in a eutrophic canyon-shaped reservoir

    Czech Academy of Sciences Publication Activity Database

    Gasol, J. M. .; Comerma, M.; García, J. C.; Armengol, J.; Casamayor, E. O.; Kojecká, Petra; Šimek, Karel

    2002-01-01

    Roč. 47, č. 1 (2002), s. 62-77. ISSN 0024-3590 R&D Projects: GA ČR GA206/99/0028 Grant ostatní: CICYT(ES) HID99-599-CO2-01; EC(XE) MIDAS MAS3-CT97-0154 Keywords : natural planktonic bacteria * bacterioplankton diversity * assemblages Subject RIV: DA - Hydrology ; Limnology Impact factor: 3.169, year: 2002

  17. Use of image analysis for estimation of microbial biomass and activity in samples of natural aquatic ecosystems

    International Nuclear Information System (INIS)

    Both quality and affordability of digital cameras, as well as of software for image analysis, have increased significantly during the past several years, facilitating their routine use in limnology. In our laboratory, we use image analysis for many tasks including determination of bacterioplankton biomass, determination of the biomass of filamentous microorganisms, and measurement of the activity of cell-associated extracellular enzymes of algae and bacteria. (authors)

  18. Genomics and Ecophysiology of Heterotrophic Nitrogen-Fixing Bacteria Isolated from Estuarine Surface Water

    OpenAIRE

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

    2015-01-01

    The ability to reduce atmospheric nitrogen (N2) to ammonia, known as N2 fixation, is a widely distributed trait among prokaryotes that accounts for an essential input of new N to a multitude of environments. Nitrogenase reductase gene (nifH) composition suggests that putative N2-fixing heterotrophic organisms are widespread in marine bacterioplankton, but their autecology and ecological significance are unknown. Here, we report genomic and ecophysiology data in relation to N2 fixation by thre...

  19. Prokaryotic Genomes and Diversity in Surface Ocean Waters: Interrogating the Global Ocean Sampling Metagenome▿ †

    OpenAIRE

    Biers, Erin J.; Sun, Shulei; Howard, Erinn C.

    2009-01-01

    The Sorcerer II Global Ocean Sampling (GOS) sequencing effort has vastly expanded the landscape of metagenomics, providing an opportunity to study the genetic potential of surface ocean water bacterioplankton on a global scale. Here we describe the habitat-based microbial diversity, both taxon evenness and taxon richness, for each GOS site and estimate genome characteristics of a typical free-living, surface ocean water bacterium. While Alphaproteobacteria and particularly SAR11 dominate the ...

  20. Bottom-Up versus Top-Down Control of Hypo- and Epilimnion Free-Living Bacterial Community Structures in Two Neighboring Freshwater Lakes▿†‡

    OpenAIRE

    Berdjeb, Lyria; Ghiglione, Jean-François; Jacquet, Stéphan

    2011-01-01

    Bacterioplankton plays a central role in the microbial functioning of lacustrine ecosystems; however, factors that constrain its structural variation are still poorly understood. Here we evaluated the driving forces exerted by a large set of environmental and biological parameters on the temporal and spatial dynamics of free-living bacterial community structures (BCS) in two neighboring perialpine lakes, Lake Bourget and Lake Annecy, which differ in trophic status. We analyzed monthly data fr...

  1. Coral cavity sponges depend on reef-derived food resources: stable isotope and fatty acid constraints

    OpenAIRE

    van Duyl, F.C.; Moodley, L; Nieuwland, G.; IJzerloo, L. van; van Soest, R.W.M.; Houtekamer, M.; Meesters, E.H.; Middelburg, J. J.

    2011-01-01

    The diet of cavity sponges on the narrow fringing reefs of Cura double dagger ao, Caribbean was studied. The origin and resources of the bulk food of these sponges, i.e., dissolved organic matter (DOM), were identified using stable carbon and nitrogen isotopes and fatty acid biomarkers. We found that phytoplankton and its derived DOM from the adjacent open sea and from reef overlying water is not the main source of food for most of the sponges examined nor is bacterioplankton. Interestingly, ...

  2. Artificial Seawater Media Facilitate Cultivating Members of the Microbial Majority from the Gulf of Mexico

    Science.gov (United States)

    Pitre, David M.; Weckhorst, Jessica Lee; Lanclos, V. Celeste; Webber, Austen T.

    2016-01-01

    ABSTRACT High-throughput cultivation studies have been successful at bringing numerous important marine bacterioplankton lineages into culture, yet these frequently utilize natural seawater media that can hamper portability, reproducibility, and downstream characterization efforts. Here we report the results of seven experiments with a set of newly developed artificial seawater media and evaluation of cultivation success via comparison with community sequencing data from the inocula. Eighty-two new isolates represent highly important marine clades, including SAR116, OM60/NOR5, SAR92, Roseobacter, and SAR11. For many, isolation with an artificial seawater medium is unprecedented, and several organisms are also the first of their type from the Gulf of Mexico. Community analysis revealed that many isolates were among the 20 most abundant organisms in their source inoculum. This method will expand the accessibility of bacterioplankton cultivation experiments and improve repeatability by avoiding normal compositional changes in natural seawater. IMPORTANCE The difficulty in cultivating many microbial taxa vexes researchers intent on understanding the contributions of these organisms to natural systems, particularly when these organisms are numerically abundant, and many cultivation attempts recover only rare taxa. Efforts to improve this conundrum with marine bacterioplankton have been successful with natural seawater media, but that approach suffers from a number of drawbacks and there have been no comparable artificial alternatives created in the laboratory. This work demonstrates that a newly developed suite of artificial-seawater media can successfully cultivate many of the most abundant taxa from seawater samples and many taxa previously only cultivated with natural-seawater media. This methodology therefore significantly simplifies efforts to cultivate bacterioplankton and greatly improves our ability to perform physiological characterization of cultures

  3. Short‐term changes in the composition of active marine bacterial assemblages in response to diesel oil pollution

    OpenAIRE

    Lanfranconi, Mariana P.; Bosch, Rafael; Nogales, Balbina

    2010-01-01

    Summary The changes caused by diesel oil pollution in the metabolically active bacterioplankton from an oligotrophic coastal location were analysed in laboratory microcosms (44 l) using 16S ribosomal RNA (16S rRNA) as molecular marker. The aim was to simulate typical hydrocarbon pollution events in a coastal area exploited for seasonal touristic activities. The experiment consisted in addition of low amounts of diesel oil without nutrients to seawater collected at different times (winter and ...

  4. Temporal Changes and Altitudinal Distribution of Aerobic Anoxygenic Phototrophs in Mountain Lakes

    Czech Academy of Sciences Publication Activity Database

    Čuperová, Zuzana; Holzer, E.; Salka, I.; Sommaruga, R.; Koblížek, Michal

    2013-01-01

    Roč. 79, č. 20 (2013), s. 6439-6446. ISSN 0099-2240 R&D Projects: GA MŠk MEB060911; GA ČR GA13-11281S; GA MŠk ED2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : FRESH-WATER BACTERIOPLANKTON * PHOTOHETEROTROPHIC BACTERIA * SURFACE WATERS Subject RIV: EE - Microbiology, Virology Impact factor: 3.952, year: 2013

  5. The issue of outwelling in the Guadiana River estuary (Portugal): some findings and research suggestions in the context of recent evidence

    OpenAIRE

    Bettencourt, A.M.; Quaresma, L.; Lança, M.J.

    2007-01-01

    Abstract The ‘‘Outwelling Theory’’ states that salt marshes play a major role in exporting production to adjacent estuarine and coastal ecosystems. However, it has been found that some marshes act as net importers instead of net exporters of organic matter and nutrients. Once we include mangroves and refine the analysis to comprehend bacterioplankton, organic and stable isotope tracers, the picture became, more complex, making room for a revival of the outwelling idea. The exchanges ...

  6. The Black Queen Hypothesis: Evolution of Dependencies through Adaptive Gene Loss

    OpenAIRE

    Morris, J. Jeffrey; Lenski, Richard E.; Zinser, Erik R

    2012-01-01

    ABSTRACT Reductive genomic evolution, driven by genetic drift, is common in endosymbiotic bacteria. Genome reduction is less common in free-living organisms, but it has occurred in the numerically dominant open-ocean bacterioplankton Prochlorococcus and “Candidatus Pelagibacter,” and in these cases the reduction appears to be driven by natural selection rather than drift. Gene loss in free-living organisms may leave them dependent on cooccurring microbes for lost metabolic functions. We prese...

  7. Controls on marine carbon fluxes via phytoplankton-mesoplankton interactions in continental shelf waters. Progress report, December 1992

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, L.; Sherr, B.F.; Sherr, E.B.

    1992-12-31

    The principal goals of our projects were to develop methods for the second phase of the Ocean Margins Program: investigations in the field. Our project is focused on: (1) Impact of grazing by phagotrophic protists on phytoplankton, particularly on phototrophic cells < 5 {mu}m in size which are not effectively grazed by metazooplankton; the impact of grazing by phagotrophic protists on bacterioplankton; and the taxon-specific growth rates of phytoplankton in situ, as they are affected by phagotrophy rates.

  8. Controls on marine carbon fluxes via phytoplankton-mesoplankton interactions in continental shelf waters

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, L.; Sherr, B.F.; Sherr, E.B.

    1992-01-01

    The principal goals of our projects were to develop methods for the second phase of the Ocean Margins Program: investigations in the field. Our project is focused on: (1) Impact of grazing by phagotrophic protists on phytoplankton, particularly on phototrophic cells < 5 [mu]m in size which are not effectively grazed by metazooplankton; the impact of grazing by phagotrophic protists on bacterioplankton; and the taxon-specific growth rates of phytoplankton in situ, as they are affected by phagotrophy rates.

  9. Controls on marine carbon fluxes via phytoplankton-mesoplankton interactions in continental shelf waters. Six month progress report

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, L.; Sherr, B.F.; Sherr, E.B.

    1992-12-31

    The project is an in-depth evaluation of the phytoplankton {yields} phagotrophic protist trophic link. The principal goals of the first year are to develop methods for the second phase of the Ocean Margins Program: investigations in the field. Our project is focused on: impact of grazing by phagotrophic protists on phytoplankton; impact of grazing by phagotrophic protists on bacterioplankton; taxon-specific growth rates of phytoplankton in situ, as they are affected by phagotrophy rates.

  10. Controls on marine carbon fluxes via phytoplankton-mesoplankton interactions in continental shelf waters

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, L.; Sherr, B.F.; Sherr, E.B.

    1992-01-01

    The project is an in-depth evaluation of the phytoplankton [yields] phagotrophic protist trophic link. The principal goals of the first year are to develop methods for the second phase of the Ocean Margins Program: investigations in the field. Our project is focused on: impact of grazing by phagotrophic protists on phytoplankton; impact of grazing by phagotrophic protists on bacterioplankton; taxon-specific growth rates of phytoplankton in situ, as they are affected by phagotrophy rates.

  11. Phosphorus use by planktonic communities in a large regulated Mediterranean river

    OpenAIRE

    Artigas, J.; Soley, S.; Pérez Baliero, M.C.; Romani, A.M.; Ruiz González, C.; Sabater, S.

    2012-01-01

    The regulation of large rivers to meet human requirements (e.g. hydroelectricity production, flood prevention, recreation activities) alters the longitudinal distribution of plankton communities and may affect their capacity to use nutrients and organic matter. Here we analyzed phosphorus (P) availability and use by phytoplankton and bacterioplankton in 6 upstream and 5 downstream sites from a reservoir system in the Ebro River (N Spain). Alkaline phosphatase activity (APA) was related to nut...

  12. Bacterial diversity along a 2600 km river continuum

    Science.gov (United States)

    Savio, Domenico; Sinclair, Lucas; Ijaz, Umer Z.; Parajka, Juraj; Reischer, Georg H.; Stadler, Philipp; Blaschke, Alfred P.; Blöschl, Günter; Mach, Robert L.; Kirschner, Alexander K. T.; Farnleitner, Andreas H.; Eiler, Alexander

    2016-01-01

    Summary The bacterioplankton diversity in large rivers has thus far been under-sampled despite the importance of streams and rivers as components of continental landscapes. Here, we present a comprehensive dataset detailing the bacterioplankton diversity along the midstream of the Danube River and its tributaries. Using 16S rRNA-gene amplicon sequencing, our analysis revealed that bacterial richness and evenness gradually declined downriver in both the free-living and particle-associated bacterial communities. These shifts were also supported by beta diversity analysis, where the effects of tributaries were negligible in regards to the overall variation. In addition, the river was largely dominated by bacteria that are commonly observed in freshwaters. Dominated by the acI lineage, the freshwater SAR11 (LD12) and the Polynucleobacter group, typical freshwater taxa increased in proportion downriver and were accompanied by a decrease in soil and groundwater-affiliated bacteria. Based on views of the metacommunity and River Continuum Concept, we interpret the observed taxonomic patterns and accompanying changes in alpha and beta diversity with the intention of laying the foundation for a unified concept for river bacterioplankton diversity. PMID:25922985

  13. Microbial communities reflect temporal changes in cyanobacterial composition in a shallow ephemeral freshwater lake.

    Science.gov (United States)

    Woodhouse, Jason Nicholas; Kinsela, Andrew Stephen; Collins, Richard Nicholas; Bowling, Lee Chester; Honeyman, Gordon L; Holliday, Jon K; Neilan, Brett Anthony

    2016-06-01

    The frequency of freshwater cyanobacterial blooms is at risk of increasing as a consequence of climate change and eutrophication of waterways. It is increasingly apparent that abiotic data are insufficient to explain variability within the cyanobacterial community, with biotic factors such as heterotrophic bacterioplankton, viruses and protists emerging as critical drivers. During the Australian summer of 2012-2013, a bloom that occurred in a shallow ephemeral lake over a 6-month period was comprised of 22 distinct cyanobacteria, including Microcystis, Dolichospermum, Oscillatoria and Sphaerospermopsis. Cyanobacterial cell densities, bacterial community composition and abiotic parameters were assessed over this period. Alpha-diversity indices and multivariate analysis were successful at differentiating three distinct bloom phases and the contribution of abiotic parameters to each. Network analysis, assessing correlations between biotic and abiotic variables, reproduced these phases and assessed the relative importance of both abiotic and biotic factors. Variables possessing elevated betweeness centrality included temperature, sodium and operational taxonomic units belonging to the phyla Verrucomicrobia, Planctomyces, Bacteroidetes and Actinobacteria. Species-specific associations between cyanobacteria and bacterioplankton, including the free-living Actinobacteria acI, Bacteroidetes, Betaproteobacteria and Verrucomicrobia, were also identified. We concluded that changes in the abundance and nature of freshwater cyanobacteria are associated with changes in the diversity and composition of lake bacterioplankton. Given this, an increase in the frequency of cyanobacteria blooms has the potential to alter nutrient cycling and contribute to long-term functional perturbation of freshwater systems. PMID:26636552

  14. Copper-complexing ligands produced by an intact estuarine microbial community in response to copper stress.

    Science.gov (United States)

    Bingham, J.; Dryden, C.; Gordon, A.

    2002-12-01

    Copper is both an important nutrient and a pollutant in the marine environment. By studying the interactions between microorganisms and copper in the Elizabeth River (VA), home to a major Naval Base, we field tested the hypothesis that picoplankton and/or bacterioplankton produce strong, copper-complexing ligands in response to elevated copper concentrations. A simple light/ dark test was used to distinguish between heterotrophic and phototrophic ligand production. Samples were bottled and moored, submerged one meter, for a week. Direct counts using DAPI stain and epiflourescence were conducted to find concentrations of picoplankton and bacterioplankton. Using cathodic stripping voltammetry, we found the total copper concentrations, and then from a titration of the ligands by copper, the ligand concentrations and conditional stability constants were obtained. The Elizabeth River naturally had between 10-20 nM total dissolved copper concentrations. However when copper complexation was considered we found that the levels of bio-available Cu(II) ions were much lower. In fact in the natural samples the levels were not high enough to affect the relative reproductive rates of several microorganisms. Naturally there was a 50 nM "buffer zone" of ligand to total dissolved copper concentration. Furthermore, when stressed with excess copper, healthy picoplankton produced enough ligand to alleviate toxicity, and rebuild the buffer zone. However bacterioplankton only produced enough ligand so that they were no longer affected. Therefore, intact estuarine communities regulate copper bioavailability and toxicity with ligand production.

  15. Bacterial diversity along a 2600 km river continuum.

    Science.gov (United States)

    Savio, Domenico; Sinclair, Lucas; Ijaz, Umer Z; Parajka, Juraj; Reischer, Georg H; Stadler, Philipp; Blaschke, Alfred P; Blöschl, Günter; Mach, Robert L; Kirschner, Alexander K T; Farnleitner, Andreas H; Eiler, Alexander

    2015-12-01

    The bacterioplankton diversity in large rivers has thus far been under-sampled despite the importance of streams and rivers as components of continental landscapes. Here, we present a comprehensive dataset detailing the bacterioplankton diversity along the midstream of the Danube River and its tributaries. Using 16S rRNA-gene amplicon sequencing, our analysis revealed that bacterial richness and evenness gradually declined downriver in both the free-living and particle-associated bacterial communities. These shifts were also supported by beta diversity analysis, where the effects of tributaries were negligible in regards to the overall variation. In addition, the river was largely dominated by bacteria that are commonly observed in freshwaters. Dominated by the acI lineage, the freshwater SAR11 (LD12) and the Polynucleobacter group, typical freshwater taxa increased in proportion downriver and were accompanied by a decrease in soil and groundwater-affiliated bacteria. Based on views of the meta-community and River Continuum Concept, we interpret the observed taxonomic patterns and accompanying changes in alpha and beta diversity with the intention of laying the foundation for a unified concept for river bacterioplankton diversity. PMID:25922985

  16. Abundance and biomass responses of microbial food web components to hydrology and environmental gradients within a floodplain of the River Danube.

    Science.gov (United States)

    Palijan, Goran

    2012-07-01

    This study investigated the relationships of time-dependent hydrological variability and selected microbial food web components. Samples were collected monthly from the Kopački Rit floodplain in Croatia, over a period of 19 months, for analysis of bacterioplankton abundance, cell size and biomass; abundance of heterotrophic nanoflagellates and nanophytoplankton; and concentration of chlorophyll a. Similar hydrological variability at different times of the year enabled partition of seasonal effects from hydrological changes on microbial community properties. The results suggested that, unlike some other studies investigating sites with different connectivity, bacterioplankton abundance, and phytoplankton abundance and biomass increased during lentic conditions. At increasing water level, nanophytoplankton showed lower sensitivity to disturbance in comparison with total phytoplankton biomass: this could prolong autotrophic conditions within the floodplain. Bacterioplankton biomass, unlike phytoplankton, was not impacted by hydrology. The bacterial biomass less affected by hydrological changes can be an important additional food component for the floodplain food web. The results also suggested a mechanism controlling bacterial cell size independent of hydrology, as bacterial cell size was significantly decreased as nanoflagellate abundance increased. Hydrology, regardless of seasonal sucession, has the potential to structure microbial food webs, supporting microbial development during lentic conditions. Conversely, other components appear unaffected by hydrology or may be more strongly controlled by biotic interactions. This research, therefore, adds to understanding on microbial food web interactions in the context of flood and flow pulses in river-floodplain ecosystems. PMID:22327270

  17. Resilience of SAR11 bacteria to rapid acidification in the high-latitude open ocean.

    Science.gov (United States)

    Hartmann, Manuela; Hill, Polly G; Tynan, Eithne; Achterberg, Eric P; Leakey, Raymond J G; Zubkov, Mikhail V

    2016-02-01

    Ubiquitous SAR11 Alphaproteobacteria numerically dominate marine planktonic communities. Because they are excruciatingly difficult to cultivate, there is comparatively little known about their physiology and metabolic responses to long- and short-term environmental changes. As surface oceans take up anthropogenic, atmospheric CO2, the consequential process of ocean acidification could affect the global biogeochemical significance of SAR11. Shipping accidents or inadvertent release of chemicals from industrial plants can have strong short-term local effects on oceanic SAR11. This study investigated the effect of 2.5-fold acidification of seawater on the metabolism of SAR11 and other heterotrophic bacterioplankton along a natural temperature gradient crossing the North Atlantic Ocean, Norwegian and Greenland Seas. Uptake rates of the amino acid leucine by SAR11 cells as well as other bacterioplankton remained similar to controls despite an instant ∼50% increase in leucine bioavailability upon acidification. This high physiological resilience to acidification even without acclimation, suggests that open ocean dominant bacterioplankton are able to cope even with sudden and therefore more likely with long-term acidification effects. PMID:26691595

  18. An Attempt to Carry out an Ecological Indication of the Plankton Ecosystem Based on Microbiological Indices.

    Science.gov (United States)

    Yakushin, V.; Golovko, T.

    2005-12-01

    Ecological indication of a water reservoir under the influence of anthropogenic factors includes structural and functional analyses of different biota components among which bacteria is one of the most important especially in ecosystem's bioenergy and control of artificial pollution. The main goal of the present study was to investigate the structure and functioning of bacterial population in ecologically different waters of Kanev reservoir to choose the most adequate parameters for evaluation of water ecosystem. The study was carried out on 10 sites of upper Kanev reservoir during summer 2004. The basic factors that influenced its hydrobiology were water flow from Kiev reservoir and discharge of industrial and household sewage from nearby cities. Such structural indices as bacteroplankton's total number and biomass, as well as the number of bacteria that metabolize easy degradable organic compounds did not show clear spatial conformity to natural laws. However, the evaluation of functional status of plankton bacteria happened to be more significant for ecological analysis of water ecosystem. Despite relatively low bacterioplankton content during the study term, its reproductive activity was very high which is typical for ecologic productivity: the speed of growth reaches maximum when nutrients are abundant while population density is low. A very characteristic feature of spatial changes of the functional indices of bacterioplankton was the increase of production intensity after water discharge from Kiev hydroelectric station's dam, terrigenic sewage inflow at recreational sites and inflow of Kiev's industrial and household sewage from river Lybid. Another important ecological characteristic of bacterioplankton was evaluation of matter and energy flow based on productivity and trophologic studies. Consumption of bacteria by zooplankton was seen at all sites and increased significantly with the presence of disturbing factors as a response to quantitative and

  19. Response of bacterial communities to environmental changes in a mesoscale subtropical watershed, Southeast China.

    Science.gov (United States)

    Hu, Anyi; Yang, Xiaoyong; Chen, Nengwang; Hou, Liyuan; Ma, Ying; Yu, Chang-Ping

    2014-02-15

    This study used 16S rRNA gene-based pyrosequencing (16S-pyrotag) to investigate both planktonic and benthic bacterial communities in two main tributaries (North River and West River) of the Jiulong River Watershed (JRW), a mesoscale subtropical watershed that has experienced intensive human perturbation in recent decades. The results of 16S-pyrotag showed that benthic bacterial communities were clearly more diverse and uniform than surface bacterioplankton communities. The results of taxonomic assignments indicated that Betaproteobacteria, Actinobacteria and Firmicutes were significantly more abundant in planktonic than in benthic communities, whereas the relative abundances of Acidobacteria, Delta-, Gammaproteobacteria, Chloroflexi and Nitrospira were higher in sediment than in water samples. In particular, several sewer- and fecal-pollution bacterial indicators were observed in water samples, implying that the water bodies of the JRW were contaminated by fecal pollution. Using the typical freshwater bacteria (TFB) taxonomic framework, 57.6 ± 10%, 27.6 ± 10.9% and 10.4 ± 6.9% of sequences recovered from planktonic communities could be assigned to lineages, clades and tribes of TFB, respectively. The relatively lower abundance of TFB implied that some unknown or unique autochthonous bacterioplankton populations occurred in the JRW. The principal coordinate analysis (PCoA) and one way analysis of similarity (ANOSIM) analysis demonstrated that planktonic bacterial community structures were significantly different between North River and West River, whereas benthic communities from these two tributaries were grouped together. Multivariate statistical analysis revealed that nutrient concentrations and stoichiometry were the key drivers of both α- and β-diversity patterns of bacterioplankton communities. Overall, our results indicate that the diversity, composition and structure of planktonic bacterial communities are sensitive to water chemistry (e.g., nutrient

  20. Determining indicator taxa across spatial and seasonal gradients in the Columbia River coastal margin.

    Science.gov (United States)

    Fortunato, Caroline S; Eiler, Alexander; Herfort, Lydie; Needoba, Joseph A; Peterson, Tawnya D; Crump, Byron C

    2013-10-01

    Bacterioplankton communities are deeply diverse and highly variable across space and time, but several recent studies demonstrate repeatable and predictable patterns in this diversity. We expanded on previous studies by determining patterns of variability in both individual taxa and bacterial communities across coastal environmental gradients. We surveyed bacterioplankton diversity across the Columbia River coastal margin, USA, using amplicon pyrosequencing of 16S rRNA genes from 596 water samples collected from 2007 to 2010. Our results showed seasonal shifts and annual reassembly of bacterioplankton communities in the freshwater-influenced Columbia River, estuary, and plume, and identified indicator taxa, including species from freshwater SAR11, Oceanospirillales, and Flavobacteria groups, that characterize the changing seasonal conditions in these environments. In the river and estuary, Actinobacteria and Betaproteobacteria indicator taxa correlated strongly with seasonal fluctuations in particulate organic carbon (ρ=-0.664) and residence time (ρ=0.512), respectively. In contrast, seasonal change in communities was not detected in the coastal ocean and varied more with the spatial variability of environmental factors including temperature and dissolved oxygen. Indicator taxa of coastal ocean environments included SAR406 and SUP05 taxa from the deep ocean, and Prochlorococcus and SAR11 taxa from the upper water column. We found that in the Columbia River coastal margin, freshwater-influenced environments were consistent and predictable, whereas coastal ocean community variability was difficult to interpret due to complex physical conditions. This study moves beyond beta-diversity patterns to focus on the occurrence of specific taxa and lends insight into the potential ecological roles these taxa have in coastal ocean environments. PMID:23719153

  1. Autotrophic and heterotrophic metabolism of microbial planktonic communities in an oligotrophic coastal marine ecosystem: seasonal dynamics and episodic events

    Directory of Open Access Journals (Sweden)

    O. Bonilla-Findji

    2010-03-01

    Full Text Available A 18 month study was performed in the Bay of Villefranche to assess the episodic and seasonal variation of autotrophic and heterotrophic ecosystem processes. A typical spring bloom was encountered, where maximum of gross primary production (GPP was followed by maxima of bacterial respiration (BR and production (BP. The trophic balance (heterotrophy vs. autotrophy of the system did not exhibit any seasonal trend although a strong intra-annual variability was observed. On average, the community tended to be net heterotrophic with a GPP threshold for a balanced metabolism of 2.8 μmol O2 l−1 d−1. Extended forest fires in summer 2003 and a local episodic upwelling in July 2003 likely supplied orthophosphate and nitrate into the system. These events were associated with an enhanced bacterioplankton production (up to 2.4-fold, respiration (up to 4.5-fold and growth efficiency (up to 2.9-fold but had no effect on GPP. A Sahara dust wet deposition event in February 2004 stimulated bacterial abundance, production and growth efficiency but not GPP. Our study suggests that short-term disturbances such as wind-driven upwelling, forest fires and Sahara dust depositions can have a significant but previously not sufficiently considered influence on phytoplankton- and bacterioplankton-mediated ecosystem functions and can modify or even mask the seasonal dynamics. The study also indicates that atmospheric deposition of nutrients and particles not only impacts phytoplankton but also bacterioplankton and could, at times, also shift systems stronger towards net heterotrophy.

  2. Autotrophic and heterotrophic metabolism of microbial planktonic communities in an oligotrophic coastal marine ecosystem: seasonal dynamics and episodic events

    Directory of Open Access Journals (Sweden)

    O. Bonilla-Findji

    2010-11-01

    Full Text Available A 18 month study was performed in the Bay of Villefranche to assess the episodic and seasonal variation of autotrophic and heterotrophic ecosystem processes. A typical spring bloom was encountered, where maximum of gross primary production (GPP was followed by maxima of bacterial respiration (BR and production (BP. The trophic balance (heterotrophy vs. autotrophy of the system did not exhibit any seasonal trend although a strong intra-annual variability was observed. On average, the community tended to be net heterotrophic with a GPP threshold for a balanced metabolism of 1.1 μmol O2 l−1 d−1. Extended forest fires in summer 2003 and a local episodic upwelling in July 2003 likely supplied orthophosphate and nitrate into the system. These events were associated with an enhanced bacterioplankton production (up to 2.4-fold, respiration (up to 4.5-fold and growth efficiency (up to 2.9-fold but had no effect on GPP. A Sahara dust wet deposition event in February 2004 stimulated bacterial abundance, production and growth efficiency but not GPP. Our study suggests that short-term disturbances such as wind-driven upwelling, forest fires and Sahara dust depositions can have a significant but previously not sufficiently considered influence on phytoplankton- and bacterioplankton-mediated ecosystem functions and can modify or even mask the seasonal dynamics. The study also indicates that atmospheric deposition of nutrients and particles not only impacts phytoplankton but also bacterioplankton and could, at times, also shift systems stronger towards net heterotrophy.

  3. Relationships between physico-chemical and microbiological parameters in the monimolimnion of a forest meromictic lake

    Directory of Open Access Journals (Sweden)

    Dorota Górniak

    2014-05-01

    Full Text Available The small meromictic Lake Zapadłe in North-Eastern Poland was the subject of our research in the vegetation period between April and November. Our study were to aim a better recognition of meromixis phenomenon and find connections between hydrochemical and microbiological parameters. Here, the monimolimnion layer was below 10 m depth with the chemocline between 13-14 m. Highly significant Spearman’s ranks correlations of P<0.05 were found between conductivity and biochemical oxygen demand (0.91, ammonium nitrogen (0.96, phosphate (0.91, iron (0.77 and manganese (0.82. Favourable conditions for bacterioplankton growth and function here included; the absence of water circulation, the presence of anaerobic conditions and hydrogen sulphide, a constant water temperature and highly significant correlations between total bacterial counts (TBC, bacterial biomass (BB and biochemical oxygen demand (BOD, conductivity, total organic carbon (TOC and dissolved organic carbon (DOC. The pool of bacteria-forming biomass increased significantly in the lower part of the monimolimnion. A highly significant correlation (P<0.05 existed between bacterial biomass (BB and their anaerobic metabolic products: ammonium (r=0.75, hydrogen sulphide (r=0.45 and phosphate (r=0.68 anaerobic metabolic products. This correlation indicated the significant proportion of anaerobic sulfate-reducing bacteria. The impact of physico-chemical parameters on bacterioplankton biomass during the June-November growth season was clearly illustrated in the correspondence canonical analysis (CCA. This recorded its greatest mass at 15 to 17 metres above the lake bed. Although no clear seasonal variations were noted in bacterioplankton composition described by Denaturing Gradient Gel Electrophoresis (DGGE. The monimolimnion lake layer contained 46 Operational Taxonomic Units (OTUs. Subsequent comparison of the upper and lower minimolimnion layers showed 37 of these OTUs were common, while 5 were

  4. Effects of coral reef benthic primary producers on dissolved organic carbon and microbial activity.

    Directory of Open Access Journals (Sweden)

    Andreas F Haas

    Full Text Available Benthic primary producers in marine ecosystems may significantly alter biogeochemical cycling and microbial processes in their surrounding environment. To examine these interactions, we studied dissolved organic matter release by dominant benthic taxa and subsequent microbial remineralization in the lagoonal reefs of Moorea, French Polynesia. Rates of photosynthesis, respiration, and dissolved organic carbon (DOC release were assessed for several common benthic reef organisms from the backreef habitat. We assessed microbial community response to dissolved exudates of each benthic producer by measuring bacterioplankton growth, respiration, and DOC drawdown in two-day dark dilution culture incubations. Experiments were conducted for six benthic producers: three species of macroalgae (each representing a different algal phylum: Turbinaria ornata--Ochrophyta; Amansia rhodantha--Rhodophyta; Halimeda opuntia--Chlorophyta, a mixed assemblage of turf algae, a species of crustose coralline algae (Hydrolithon reinboldii and a dominant hermatypic coral (Porites lobata. Our results show that all five types of algae, but not the coral, exuded significant amounts of labile DOC into their surrounding environment. In general, primary producers with the highest rates of photosynthesis released the most DOC and yielded the greatest bacterioplankton growth; turf algae produced nearly twice as much DOC per unit surface area than the other benthic producers (14.0±2.8 µmol h⁻¹ dm⁻², stimulating rapid bacterioplankton growth (0.044±0.002 log10 cells h⁻¹ and concomitant oxygen drawdown (0.16±0.05 µmol L⁻¹ h⁻¹ dm⁻². Our results demonstrate that benthic reef algae can release a significant fraction of their photosynthetically-fixed carbon as DOC, these release rates vary by species, and this DOC is available to and consumed by reef associated microbes. These data provide compelling evidence that benthic primary producers differentially influence

  5. Short-term changes in the composition of active marine bacterial assemblages in response to diesel oil pollution.

    Science.gov (United States)

    Lanfranconi, Mariana P; Bosch, Rafael; Nogales, Balbina

    2010-09-01

    The changes caused by diesel oil pollution in the metabolically active bacterioplankton from an oligotrophic coastal location were analysed in laboratory microcosms (44 l) using 16S ribosomal RNA (16S rRNA) as molecular marker. The aim was to simulate typical hydrocarbon pollution events in a coastal area exploited for seasonal touristic activities. The experiment consisted in addition of low amounts of diesel oil without nutrients to seawater collected at different times (winter and summer). Bacterial diversity was analysed by terminal-restriction fragment length polymorphism (T-RFLP) profiling of 16S rRNAs after reverse transcription polymerase chain reaction (RT-PCR), and by generation of 16S rRNA clone libraries in control and diesel-polluted microcosms. Diesel addition caused a twofold increase in prokaryotic numbers in comparison with controls at the end of the experiment, both in winter and summer microcosms. Bacterioplankton composition, determined by 16S rRNA T-RFLP data, changed rapidly (within 17 h) in response to treatment. The resulting communities were different in microcosms with water collected in summer and winter. A reduction in diversity (Shannon index, calculated on the basis of T-RFLP data) was observed only in summer microcosms. This was due to the rapid increase of phylotypes affiliated to the Oceanospirillaceae, not observed in winter microcosms. After diesel treatment there was a reduction in the number of phylotypes related to SAR11, SAR86 and picocyanobacteria, while phylotypes of the Roseobacter clade, and the OMG group seemed to be favoured. Our results show that diesel pollution alone caused profound effects on the bacterioplankton of oligotrophic seawater, and explained many of the differences in diversity reported previously in pristine and polluted sites in this coastal area. PMID:21255357

  6. Synergistic and antagonistic effects of viral lysis and protistan grazing on bacterial biomass, production and diversity

    Czech Academy of Sciences Publication Activity Database

    Weinbauer, M.G.; Horňák, Karel; Jezbera, Jan; Nedoma, Jiří; Dolan, J. R.; Šimek, Karel

    2007-01-01

    Roč. 9, č. 3 (2007), s. 777-788. ISSN 1462-2912 R&D Projects: GA ČR(CZ) GA206/05/0007 Grant ostatní: MGW(FR) ATIPE; MŠMT(CZ) Barrande 2004-004-2 Institutional research plan: CEZ:AV0Z60170517 Source of funding: V - iné verejné zdroje Keywords : in-situ hybridization * bacterioplankton * viruses * community composition * eutrophic reservoir * growth-rate * food webs Subject RIV: EE - Microbiology, Virology Impact factor: 4.929, year: 2007

  7. Annual Cycle of Bacterial Specific Biovolumes in Howe Sound, a Canadian West Coast Fjord Sound

    OpenAIRE

    Albright, L. J.; McCrae, S. K.

    1987-01-01

    The mean specific biovolumes (biovolume cell−1) of the bacterioplankton within a 250-m-deep water column in Howe Sound, British Columbia, were determined for the period of 4 September 1984 to 23 October 1985. These bacteria had an annual cycle in mean specific biovolume; they were small (ca. 0.058 μm3) in mid-winter, larger in spring (ca. 0.076 μm3), larger again in summer (up to 0.102 μm3), and largest (ca. 0.133 μm3) in early fall (immediately after the decrease in phytoplankton production)...

  8. Lower Seine river and estuary (France) carbon and oxygen budgets during low flow

    OpenAIRE

    J. Garnier; Servais, P.; Billen, G.; Akopian, M.; Brion, N.

    2001-01-01

    Ecological processes driving the oxygen budget were investigated in the downstream part of the Seine River and its estuary. Phytoplankton and bacterioplankton production were measured along longitudinal profiles (11 to 17 stations) in a range of low discharges from 300 m³ s -1 in 1993 and 1995 to 140 m³ s -1 in 1996. Values representative of the water column were based on investigations carried out during two tidal cycles. Net primary production was invariably greatest in the freshwater estua...

  9. Bacterial pollution of the riverine surface microlayer and subsurface water.

    Science.gov (United States)

    Skórczewski, Piotr; Mudryk, Zbigniew

    2009-01-01

    The density and distribution of bacteria indicative of pollution in the surface microlayer and subsurface water of the River Słupia were estimated. The number of heterotrophic bacteria, total coliforms, fecal coliforms and fecal streptococci were higher in the surface microlayer than in the underlying water. The average bacterial enrichment factor (EF) of the parameters studied in the bacterioneuston was 1.7 to 1.8 times higher than in bacterioplankton. During the annual study cycle, bacterial pollution indicators inhabiting the surface microlayer and subsurface water showed considerable monthly changes. PMID:19587410

  10. Impacts of diverted freshwater on dissolved organic matter and microbial communities in Barataria Bay, Louisiana, U.S.A.

    Science.gov (United States)

    Bianchi, Thomas S; Cook, Robert L; Perdue, E Michael; Kolic, Paulina E; Green, Nelson; Zhang, Yaoling; Smith, Richard W; Kolker, Alexander S; Ameen, Alex; King, Gary; Ojwang, Loice M; Schneider, Caroline L; Normand, Anna E; Hetland, Robert

    2011-12-01

    Here we present results of an initial assessment of the impacts of a water diversion event on the concentrations and chemical composition of dissolved organic matter (DOM) and bacterioplankton community composition in Barataria Bay, Louisiana U.S.A, an important estuary within the Mississippi River Delta complex. Concentrations and spectral properties of DOM, as reflected by UV/visible absorbance and fluorescence, were strikingly similar at 26 sites sampled along transects near two western and two eastern areas of Barataria Bay in July and September 2010. In September 2010, dissolved organic carbon (DOC) was significantly higher (568.1-1043 μM C, x=755.6+/-117.7 μM C, n=14) than in July 2010 (249.1-577.1 μM C, x=383.7+/-98.31 μM C, n=14); conversely, Abs254 was consistently higher at every site in July (0.105-0.314) than in September (0.080-0.221), averaging 0.24±0.06 in July and 0.15±0.04 in September. Fluorescence data via the fluorescence index (FI450/500) revealed that only 30% (8 of 26) of the July samples had an FI450/500 above 1.36, compared to 96% (25 of 26) for the September samples. This indicates a more terrestrial origin for the July DOM. Bacterioplankton from eastern sites differed in composition from bacterioplankon in western sites in July. These differences appeared to result from reduced salinities caused by the freshwater diversion. Bacterioplankton communities in September differed from those in July, but no spatial structure was observed. Thus, the trends in bacterioplankton and DOM were likely due to changes in water masses (e.g., input of Mississippi River water in July and a return to estuarine waters in September). Discharge of water from the Davis Pond Freshwater Diversion (DPFD) through Barataria Bay may have partially mitigated some adverse effects of the oil spill, inasmuch as DOM is concerned. PMID:22000271

  11. Role of nutrient recycling in upwelling ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Whitledge, T E

    1979-01-01

    The regeneration of nitrogen is an important process that increases the efficiency of the upwelling ecosystem by enlarging their spatial scales. Ammonium regeneration was considered to contribute 42 to 72 percent of phytoplankton nitrogen requirements in the northwest Africa, Peru, and Baja California upwelling systems. Zooplankton are responsible for the largest portion of regenerated nitrogen; however, fish and benthic sediments may be nearly as large. Comparisons of the importance of ammonium regeneration in upwelling areas with coastal and open ocean regions indicate that the percentage contributions are similar. Future nutrient regeneration studies are needed to assess the recycling of benthic sediments, microzooplankton, gelatinous zooplankton, demersal fish, bacterioplankton, and mollusks.

  12. Metatranscriptomic and functional metagenomic analysis of methylphosphonate utilization by marine bacteria

    Directory of Open Access Journals (Sweden)

    Asuncion eMartinez

    2013-11-01

    Full Text Available Aerobic degradation of methylphosphonate (MPn by marine bacterioplankton has been hypothesized to contribute significantly to the ocean’s methane supersaturation, yet little is known about MPn utilization by marine microbes. To identify the microbial taxa and metabolic functions associated with MPn-driven methane production we performed parallel metagenomic, metatranscriptomic, and functional screening of microcosm perturbation experiments using surface water collected in North Pacific Subtropical Gyre. In nutrient amended microcosms containing MPn, a substrate-driven microbial succession occurred. Initially, the addition of glucose and nitrate resulted in a bloom of Vibrionales and a transcriptional profile dominated by glucose-specific PTS transport and polyhydroxyalkanoate biosynthesis. Transcripts associated with phosphorus (P acquisition were also overrepresented and suggested that the addition of glucose and nitrate had driven the community to P depletion. At this point, a second community shift occurred characterized by the increase in C-P lyase containing microbes of the Vibrionales and Rhodobacterales orders. Transcripts associated with C-P lyase components were among the most highly expressed at the community level, and only C-P lyase clusters were recovered in a functional screen for MPn utilization, consistent with this pathway being responsible for the majority, if not all the methane accumulation we observed. Our results identify specific bacterioplankton taxa that can utilize MPn aerobically under conditions of P limitation using the C-P lyase pathway, and thereby elicit a significant increase in the dissolved methane concentration.

  13. Nitrogen fixation in the Southern Ocean: a case of study of the Fe-fertilized Kerguelen region (KEOPS II cruise

    Directory of Open Access Journals (Sweden)

    M. L. González

    2014-12-01

    Full Text Available N2 fixation rates were measured during the KEOPS2 cruise in the HNLC area of Southern Ocean and in naturally iron-fertilized waters (Kerguelen Island 49.25° S, 69.58° E using the 15N isotopic technique. We detected N2 fixation within the mixed layer at all stations, from the surface to 140 m depth. The data shows high variability with rates ranging between 0.42 and 20.11 nmol N L−1 d−1. The highest rates were concentrated in the euphotic layer and maximum values were obtained north of polar front (station F-L, which coincide with a positive N* ([NO3]–16[PO4], high chlorophyll concentration and dissolved iron. N2 fixation rates were also obtained in stations with moderate (A3-2; E-4W and also low (R-2 iron levels as well as Chl a, suggesting that beside the microbial biomass, its composition/structure is a driving factor controlling N2 fixation activities. Molecular analysis showed a diazotrophic community dominated by heterotrophic bacterioplankton. Size fractioned experiments indicated that most of N2 fixating activities came from 2 fixation is occurring in the Southern Ocean, at rates exceeding previous reports for high latitudes. Our findings suggest an indirect role of dFe in the regulation of N2 fixation through the enhancement of regenerated primary production and the availability of phytoplankton-derived dissolved organic matter, which in turn may stimulate heterotrophic bacterioplankton.

  14. Abundance of broad bacterial taxa in the sargasso sea explained by environmental conditions but not water mass.

    Science.gov (United States)

    Sjöstedt, Johanna; Martiny, Jennifer B H; Munk, Peter; Riemann, Lasse

    2014-05-01

    To explore the potential linkage between distribution of marine bacterioplankton groups, environmental conditions, and water mass, we investigated the factors determining the abundance of bacterial taxa across the hydrographically complex Subtropical Convergence Zone in the Sargasso Sea. Based on information from 16S rRNA gene clone libraries from various locations and two depths, abundances of the predominant taxa (eubacteria, Archaea, Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes, and the Roseobacter, SAR11, and SAR86 clades) were quantified by real-time PCR. In addition, the abundances of Synechococcus, Prochlorococcus, and picoalgae were determined by flow cytometry. Linear multiple-regression models determining the relative effects of eight environmental variables and of water mass explained 35 to 86% of the variation in abundance of the quantified taxa, even though only one to three variables were significantly related to any particular taxon's abundance. Most of the variation in abundance was explained by depth and chlorophyll a. The predominant phototrophs, Prochlorococcus and picoalgae, were negatively correlated with phosphate, whereas eubacteria, heterotrophic bacteria, and SAR86 were negatively correlated with nitrite. Water mass showed limited importance for explaining the abundance of the taxonomical groups (significant only for Roseobacter, explaining 14% of the variation). The results suggest the potential for predicting the abundance of broad bacterioplankton groups throughout the Sargasso Sea using only a few environmental parameters. PMID:24561593

  15. Bacterial survival governed by organic carbon release from senescent oceanic phytoplankton

    Directory of Open Access Journals (Sweden)

    S. Lasternas

    2013-10-01

    Full Text Available Bacteria recycle vast amounts of organic carbon, playing key biogeochemical and ecological roles in the ocean. Bacterioplankton dynamics are expected to be dependent on phytoplankton primary production, but there is a high diversity of processes (e.g. sloppy feeding, cell exudation, viral lysis involved in the transference of primary production to dissolved organic carbon available to bacteria. Here we show cell survival of heterotrophic bacterioplankton in the subtropical Atlantic Ocean to be determined by phytoplankton extracellular carbon release (PER. PER represents the fraction of primary production released as dissolved organic carbon, and changes in the PER variability was explained by phytoplankton cell death, with the communities experiencing the highest phytoplankton cell mortality showing a larger proportion of extracellular carbon release. Both PER and the percent of dead phytoplankton cells increased from eutrophic to oligotrophic waters, while heterotrophic bacteria communities, including 60 to 95% of living cells (%LC, increased from the productive to the most oligotrophic waters. The percentage of living heterotrophic bacterial cells increased with increasing phytoplankton extracellular carbon release, across oligotrophic to productive waters in the NE Atlantic, where lower PER have resulted in a decrease in the flux of phytoplankton DOC per bacterial cell. The results highlight phytoplankton cell death as a process influencing the flow of dissolved photosynthetic carbon in the NE Atlantic Ocean, and demonstrated a close coupling between the fraction of primary production released and heterotrophic bacteria survival.

  16. Direct and Indirect Evidence of Size-Selective Grazing on Pelagic Bacteria by Freshwater Nanoflagellates

    Science.gov (United States)

    Šimek, Karel; Chrzanowski, Thomas H.

    1992-01-01

    Size-selective grazing of three heterotrophic nanoflagellates (with cell sizes of 21, 44, and 66 μm3) isolated from Lake Arlington, Texas was examined by using a natural mixture of fluorescence labelled lake bacteria. Sizes of ingested bacteria in food vacuoles were directly measured. Larger bacterial cells were ingested at a frequency much higher than that at which they occurred in the assemblage, indicating preferential flagellate grazing on the larger size classes within the lake bacterioplankton. Water samples were collected biweekly from June through September, 1989, fractionated by filtration, and incubated for 40 h at in situ temperatures. The average bacterial size was always larger in water which was passed through 1-μm-pore-size filters (1-μm-filtered water) (which was predator free) than in 5-μm-filtered water (which contained flagellates only) or in unfiltered water (in which all bacterivores were present). The increase of bacterial-cell size in 1-μm-filtered water was caused by a shift in the size structure of the bacterioplankton population. Larger cells became more abundant in the absence of flagellate grazing. PMID:16348811

  17. Influence of mineral suspension on the phytoplankton growth

    Science.gov (United States)

    Schure, L. A.; Aponasenko, A. D.; Postnikova, P. V.; Filimonov, V. S.; Lopatin, V. N.

    2006-02-01

    Effect of organomineral suspension on development of plankton community which are included in microbial food web has been studied in the laboratory and in the field. In the course of the model experiment it was found that in samples with adding suspension the chlorophyll concentration (C chl) increase runs more intensively and the longer time period. Increase C chl in the control ran up to 67 days with the following going out to the stationary level at maximum value 220 mkg/l. In samples with adding 100 mg/l suspension the stationary level was not reached to the 80 days of the experiment and the maximum chlorophyll concentration made 520 mkg/l. In field studies it was ascertained that all the parameters related to production characteristics of bacterioplankton as well as to organic matter adsorbed on mineral suspension greatly influence the production characteristics of phytoplankton. The multiplicative model of dependence of a primary production from primary factors of environment: the content of chlorophyll, specific absorption coefficient of light by the dissolved organic matter, content of adsorbed organic matter, bacterial production and destruction, mean size of phytoplankton cells is offered. It would follow from this model that if bacterioplankton production increases twice (at remaining other parameters constant) then primary production will be 2.5 times larger in the Khanka Lake, 1.9 times in the Yenisei River and 1.4 times in Krasnoyarsk water storage.

  18. The source of the river as a nursery for microbial diversity.

    Science.gov (United States)

    de Oliveira, Luiz Felipe Valter; Margis, Rogério

    2015-01-01

    Bacteria are highly diverse and ubiquitous organisms that play a key role as drivers for ecosystem processes. The application of NGS (next-generation sequencing technologies) for 16S analysis has been broadly used for understanding bacterioplankton composition and structure. Most of studies conducted on aquatic ecosystems with 16S NGS have been in seawater and lakes. A few studies using NGS have been conducted in river environments and have suggested the presence of a bacterial seed-bank. We performed 16S highly variable V4 region high-throughput analysis in the Sinos River, which is located in one of most important Brazilian industrial centers. This region has several contrasts in its environmental characteristics, presenting a longitudinal gradient of eutrophication and making it a remarkable study site for observing the dynamics of bacterioplankton. We demonstrated consistent evidence for the existence of a bacterial seed-bank and its longitudinal persistence. Seasonal shifts reinforce the importance of the source of the river in maintaining the bacterial seed-bank that spreads throughout the river. Therefore, the preservation of the source of the river is important not only for hydrologic reasons but also to maintain the microbial composition and the ecological integrity of the river. PMID:25803426

  19. [Monitoring of the Moskva River Water Using Microbiological Parameters and Chlorophyll a Fluorescence].

    Science.gov (United States)

    Mosharova, I V; Il'inskii, V V; Matorin, D N; Mosharov, S A; Akulova, A Yu; Protopopov, F F

    2015-01-01

    The results of investigations of three Moskva River sites with different degree of pollution using a complex of microbiological characteristics and the parameters of chlorophyll a fluorescence are presented. We determined that the bacterioplankton seasonal dynamics at less polluted waters (Tushino and Vorobyovy Gory) were similar and differed significantly from one in more polluted waters (Dzerzhinskii). The number of bacteria with active electron transport chain, as well as their share in the bacterioplankton structure, was higher in the water of Dzerzhinskii (average annual values of 0.23 x 10(6) cells/mL and 14%), that in the less polluted water of Tushino and Vorobyovy Gory (0.14 x 10(6) cells/mL; 6% and 0.15 x 10(6) cells/mL; 7%, respectively). From April to October, the content of chlorophyll a and its photosynthetic activity were the highest in Tushino. In Dzerzhinskii, during spring the increase in photosynthetic activity commenced earlier and was more intensive that the increase in chlorophyll a content, i.e., the increase in phytoplankton biomass was temporarily suppressed. We suggest association of this phenomenon with suppression of organic matter synthesis by phytoplankton due to the high water pollution in Dzerzhinskii. The second autumn peak of chlorophyll a content, that was typical of clear water and was observed in Tushino, did not occur in Dzerzhinskii. We recommend combined application of these microbiological parameters and characteristics of chlorophyll a fluorescence for a monitoring. PMID:26964361

  20. Size distribution of planktonic autotrophy and microheterotrophy in DeGray Reservoir, Arkansas

    Energy Technology Data Exchange (ETDEWEB)

    Kimmel, B.L.; Groeger, A.W.

    1983-01-01

    Naturally occurring assemblages of phytoplankton and bacterioplankton were radiolabelled with sodium /sup 14/C-bicarbonate and sodium /sup 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 <8.0 ..mu..m. Microheterotrophic activity in the 0.2- to 1.0-..mu..m size fraction, presumably associated with free-living bacterioplankton not attached to suspended particles, usually accounted for >75% of the planktonic microheterotrophy. Longitudinal patterns in autotrophic and microheterotrophic activities associated with >3-..mu..m and >1-..mu..m size fractions, respectively, suggest an uplake to downlake shift from riverine to lacustrine environmental influences within the reservoir. 83 references, 7 figures.

  1. Virioplankton in the Kara Sea: The impact of viruses on mortality of heterotrophic bacteria

    Science.gov (United States)

    Kopylov, A. I.; Sazhin, A. F.; Zabotkina, E. A.; Romanova, N. D.

    2015-07-01

    Studies were conducted in shallow and deepwater areas of the Kara Sea. The abundance of bacteria ( N B ) and the abundance of viruses ( N V ) ranged within (19.4-2215.1) × 103 cells/ml and (97.6-5796.8) × 103 particles/ml, respectively. The virus to bacteria ratio varied from 1.4 to 29.1. A positive correlation was found between N B and N V ( R = 0.87, n = 45, p = 0.05. Using electron transmission microscopy it was detected that the frequency of visibly infected cells of bacteria (FVIC) varied from 0.2 to 1.9% of N B . The maximum values of FVIC were recorded in the estuary of the Yenisei River. The infected cells of bacteria contained from 4 to 127 (an average of 12) phages/cell of mature viruses. Virus-mediated mortality of bacteria was 0.5% and varied from 1.4 to 16.1% of the total mortality of bacterioplankton. This indicates a minor role of viruses in the control of overabundance and production of bacterioplankton in the Kara Sea during the surveyed period.

  2. Prey selectivity of bacterivorous protists in different size fractions of reservoir water amended with nutrients.

    Science.gov (United States)

    Jezbera, Jan; Hornák, Karel; Simek, Karel

    2006-08-01

    An experiment designed to examine food preferences of heterotrophic nanoflagellates (HNF) grazing on bacterioplankton was performed in the freshwater Rímov reservoir (Czech Republic). Water samples were size-fractionated to obtain preferences by analysing bacterial prey in HNF food vacuoles compared with available bacteria. Actinobacteria (the HGC69a probe) were avoided by HNF in all treatments. Cytophaga-Flavobacterium-Bacteroidetes bacteria (the CF319a probe) were positively selected mainly in treatments in which bacteria were heavily grazed, the < 5 microm treatments, but this trend was less pronounced towards the end of the study. The members of a small subcluster of Betaproteobacteria (the R-BT065 probe) were mostly positively selected. The nutrient amendments differentially affected bacterioplankton dynamics in almost all treatments, and together with the size fractionation, altered HNF overall bacterivory as well as prey selection. Analyses of bacterivores in unfiltered treatments allowed to detect the effect of different protists on shifts in HNF selectivity observed in < 5 microm compared with unfiltered treatments. PMID:16872397

  3. Uncoupled viral and bacterial distributions in coral reef waters of Tuamotu Archipelago (French Polynesia).

    Science.gov (United States)

    Bouvy, Marc; Combe, Marine; Bettarel, Yvan; Dupuy, Christine; Rochelle-Newall, Emma; Charpy, Loic

    2012-01-01

    This study examined the distribution of virioplankton and bacterioplankton in two coral reef systems (Ahe and Takaroa atolls) in the Tuamotu Archipelago, in comparison with the surrounding oligotrophic ocean. Mean concentrations of 4.8×10(5) and 6.2×10(5) cells ml(-1) for bacteria and 8.1×10(6) and 4.3×10(6) VLP(virus-like particle) ml(-1) were recorded in Ahe and Takaroa lagoons, respectively. Chlorophyll-a concentrations and dissolved organic matter were higher in Ahe whereas (3)H thymidine incorporation rates were higher in Takaroa. First data on lytic and lysogenic strategies of phages in coral reef environments were discussed in this paper. The fraction of visibly infected cells by viruses was negligible regardless of the lagoon station (mean=0.15%). However, the fraction of lysogenic cells ranged between 2.5% and 88.9%. Our results suggest that the distribution patterns of virioplankton are apparently not coupled to the spatial dynamics of the bacterioplankton communities. PMID:22284701

  4. Size distribution of planktonic autotrophy and microheterotrophy in DeGray Reservoir, Arkansas

    International Nuclear Information System (INIS)

    Naturally occurring assemblages of phytoplankton and bacterioplankton were radiolabelled with sodium 14C-bicarbonate and sodium 3H-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

  5. COUPLED PHYSICAL-ECOLOGICAL MODELLING IN THE CENTRAL PART OF JIAOZHOU BAY Ⅱ. COUPLED WITH AN ECOLOGICAL MODEL

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Sharples' 1-D physical model employing tide-wind driven turbulence closure and surface heating-cooling physics, was coupled with an ecological model with 9-biochemical components: phytoplankton, zooplankton, shellfish, autotrophic and heterotrophic bacterioplankton, dissolved organic carbon (DOC), suspended detritus and sinking particles to simulate the annual evolution of ecosystem in the central part of Jiaozhou Bay. The coupled modeling results showed that the phytoplankton shading effect could reduce seawater temperature by 2℃, so that photosynthesis efficiency should be less than 8%; that the loss of phytoplankton by zooplankton grazing in winter tended to be compensated by phytoplankton advection and diffusion from the outside of the Bay; that the incident irradiance intensity could be the most important factor for phytoplankton growth rate; and that it was the bacterial secondary production that maintained the maximum zooplankton biomass in winter usually observed in the 1990s, indicating that the microbial food loop was extremely important for ecosystem study of Jiaozhou Bay.

  6. Phylogenetic relationship and phenotypic comparison of Psychrobacter species isolated from polar oceans

    Institute of Scientific and Technical Information of China (English)

    ZENG Yinxin; LI Huirong; YU Yong; CHEN Bo

    2007-01-01

    To investigate the phylogenetic relationship and biogeography of bacterioplankton in polar oceans, four Psychrobacter strains, BSw10170, BSw20352, BSw20370, and BSw20461, isolated from seawater of the Bering Sea, the Chukchi Sea, and the Prydz Bay, were characterized by 16S rDNA sequencing and physiological and biochemical testing. Results demonstrated that close relationships existed between the Arctic and Antarctic strains with sequence similarities higher than 97%. These four Psychrobacter strains not only showed almost identical phenotypic characteristics among them, but also shared a lot of similarities with those related Psychrobacter species, indicating that psychrotolerance and halotolerance of Psychrobacter strains may be among the reasons for their bipolar, even global distribution in marine environments at the genus level.

  7. Individual particle analyses

    Science.gov (United States)

    Cowen, James P.

    Marine particulate matter consists of a complex, heterogeneous population of reactive and interactive particles. In oligotrophic oceans, particles are produced primarily by phytoplankton within the euphotic zone. Secondary production by bacterioplankton is also an important source of particles and mid-water column chemolithoautotrophy or horizontal advection may provide additional new particles [Sorokin, 1971; Pomeroy, 1974; Sieburth, 1976; Lambert et al., 1981; Karl et al., 1984]. Aeolian input can be an important source of abiogenic particles such as clay minerals [Sutcliffe et al., 1963; Buat-Menard and Chesselet, 1979; Deuser et al., 1981, 1983] while other abiogenic particles may precipitate or flocculate in situ [McCave, 1984; Feely et al., 1990]. In coastal area rivers, runoff, and resuspension can provide additional important sources of particles.

  8. Turnover of extracellular DNA in eutrophic and oligotrophic freshwater environments of southwest Florida

    Energy Technology Data Exchange (ETDEWEB)

    Paul, J.H.; Jeffrey, W.H.; David, A.W.; DeFlaun, M.F.; Cazares, L.H.

    1989-01-01

    Turnover of extracellular DNA was investigated in oligotrophic springs of the Crystal River and the eutrophic Medard Reservoir of southwest Florida. The Medard Reservoir possessed large populations of bacterioplankton and phytoplankton (6.8 x 10 sup 9 cells per liter and 28.6 micrograms of chlorophyll a per liter, respectively), while the Crystal River springs only contained a fraction of the microbial biomass found in the Medard Reservoir. The results indicate that regardless of trophic status or microbial standing stock, extracellular DNA turns over rapidly in subtropical planktonic freshwater environments. Therefore, recombinant DNA sequences from released genetically engineered microorganisms might not be expected to survive for long periods of time in freshwater planktonic environments.

  9. Size distribution of planktonic autotrophy and microheterotrophy in DeGray and West Point reservoirs: a comparative study. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kimmel, B.L.; Groeger, A.W.

    1985-09-01

    Particle size is an important determinant of food resources available to planktonic consumers and of the efficiency of energy transfer through planktonic foodwebs. Thus, the environmental factors controlling the size distributions of planktonic autotrophy (algal photosynthesis) and microheterotrophy (bacterial heterotrophic activity) are of considerable ecological interest. To examine hypotheses regarding their environmental control, we compared the size distributions of planktonic autotrophy and microheterotrophy within and between oligotrophic DeGray Reservoir (Arkansas) and eutrophic West Point Reservoir (Alabama-Georgia). Naturally occurring assemblages of reservoir phytoplankton and bacterioplankton were radiolabeled with sodium /sup 14/C-bicarbonate and sodium /sup 3/H-acetate and were size fractionated by filtration through polycarbonate membrane filters. 92 refs., 12 figs., 7 tabs.

  10. A key role of aluminium in phosphorus availability, food web structure, and plankton dynamics in strongly acidified lakes

    Czech Academy of Sciences Publication Activity Database

    Vrba, Jaroslav; Kopáček, Jiří; Bittl, T.; Nedoma, Jiří; Štrojsová, Alena; Nedbalová, Linda; Kohout, L.; Fott, J.

    2006-01-01

    Roč. 61, Suppl. 20 (2006), S441-S451. ISSN 0006-3088 R&D Projects: GA ČR(CZ) GA206/97/0072; GA ČR(CZ) GA206/00/0063; GA ČR(CZ) GA206/03/1583; GA AV ČR(CZ) IAA6017202 Grant ostatní: FRVŠ(CZ) G4 1841; MSM(CZ) 6007665801; EC(XE) GOCE-CT-2003-505298 Institutional research plan: CEZ:AV0Z60170517; CEZ:AV0Z60050516 Keywords : extracellular phosphatases * bacterioplankton * phytoplankton * zooplankton * acidification * recovery Subject RIV: EE - Microbiology, Virology Impact factor: 0.213, year: 2006

  11. Quick stimulation of Alcanivorax sp. by bioemulsificant EPS2003 on microcosm oil spill simulation

    Directory of Open Access Journals (Sweden)

    Simone Cappello

    2014-12-01

    Full Text Available Oil spill microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS2003 on quick stimulation of hydrocarbonoclastic bacteria. Early hours of oil spill, were stimulated using an experimental seawater microcosm, supplemented with crude oil and EPS2003 (SW+OIL+EPS2003; this system was monitored for 2 days and compared to control microcosm (only oil-polluted seawater, SW+OIL. Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out. Community composition of marine bacterioplankton was determined by 16S rRNA gene clone libraries. Data obtained indicated that bioemulsificant addition stimulated an increase of total bacterial abundance and, in particular, selection of bacteria related to Alcanivorax genus; confirming that EPS2003 could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process.

  12. Quick stimulation of Alcanivorax sp. by bioemulsificant EPS₂₀₀₃ on microcosm oil spill simulation.

    Science.gov (United States)

    Cappello, Simone; Genovese, Maria; Denaro, Renata; Santisi, Santina; Volta, Anna; Bonsignore, Martina; Mancini, Giuseppe; Giuliano, Laura; Genovese, Lucrezia; Yakimov, Michail M

    2014-01-01

    Oil spill microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS₂₀₀₃) on quick stimulation of hydrocarbonoclastic bacteria. Early hours of oil spill, were stimulated using an experimental seawater microcosm, supplemented with crude oil and EPS₂₀₀₃ (SW+OIL+EPS₂₀₀₃); this system was monitored for 2 days and compared to control microcosm (only oil-polluted seawater, SW+OIL). Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out. Community composition of marine bacterioplankton was determined by 16S rRNA gene clone libraries. Data obtained indicated that bioemulsificant addition stimulated an increase of total bacterial abundance and, in particular, selection of bacteria related to Alcanivorax genus; confirming that EPS₂₀₀₃ could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process. PMID:25763036

  13. Direct and indirect effects of the glyphosate formulation Glifosato Atanor® on freshwater microbial communities.

    Science.gov (United States)

    Vera, María Solange; Di Fiori, Eugenia; Lagomarsino, Leonardo; Sinistro, Rodrigo; Escaray, Roberto; Iummato, María Mercedes; Juárez, Angela; Ríos de Molina, María del Carmen; Tell, Guillermo; Pizarro, Haydée

    2012-10-01

    Glyphosate-based formulations are among the most widely used herbicides in the world. The effect of the formulation Glifosato Atanor(®) on freshwater microbial communities (phytoplankton, bacterioplankton, periphyton and zooplankton) was assessed through a manipulative experiment using six small outdoor microcosms of small volume. Three of the microcosms were added with 3.5 mg l(-1) of glyphosate whereas the other three were left as controls without the herbicide. The treated microcosms showed a significant increase in total phosphorus, not fully explained by the glyphosate present in the Glifosato Atanor(®). Therefore, part of the phosphorus should have come from the surfactants of the formulation. The results showed significant direct and indirect effects of Glifosato Atanor(®) on the microbial communities. A single application of the herbicide caused a fast increase both in the abundance of bacterioplankton and planktonic picocyanobacteria and in chlorophyll a concentration in the water column. Although metabolic alterations related to oxidative stress were induced in the periphyton community, the herbicide favored its development, with a large contribution of filamentous algae typical of nutrient-rich systems, with shallow and calm waters. An indirect effect of the herbicide on the zooplankton was observed due to the increase in the abundance of the rotifer Lecane spp. as a consequence of the improved food availability given by picocyanobacteria and bacteria. The formulation affected directly a fraction of copepods as a target. It was concluded that the Glifosato Atanor(®) accelerates the deterioration of the water quality, especially when considering small-volume water systems. PMID:22539117

  14. Bioavailability of surface dissolved organic matter to aphotic bacterial communities in the Amundsen Sea Polynya, Antarctica

    Directory of Open Access Journals (Sweden)

    Rachel E. Sipler

    2015-07-01

    Full Text Available Abstract Antarctic seas, and particularly the Amundsen Sea Polynya, are some of the most productive oceanic regions on Earth. Ice-algal production during austral spring is followed by open-water pelagic production later in the season. Although ice-free growth accounts for a greater percentage of the annual net primary production, ice algae provide an important source of nutrients to organisms throughout the water column and benthos in areas and seasons when open-water production is insignificant. The objectives of this study were to assess the bioavailability of dissolved organic matter (DOM, sourced from ice algae or the chlorophyll maximum (chl max, to marine bacterioplankton and to determine the fate of carbon within these different DOM pools, including loss to respiration, incorporation into bacterial biomass and retention within the DOM pool itself. Nutrient concentrations and bacterial abundance, production, and cell volume were monitored during a 7-day bioassay study involving four treatments conducted shipboard in the Amundsen Sea Polynya, Antarctica. The greatest response in bacterial abundance and activity was observed when ice-algal meltwater was supplied to aphotic zone bacterioplankton collected from 170-m depth. However, bacterial growth efficiency was higher (24% when chl max water was supplied to the same aphotic zone bacterial community compared to the bacterial growth efficiency of the ice-algal treatment (15%. Approximately 15% of dissolved organic carbon (DOC from the ice-algal source and 18% from the chl max was consumed by aphotic bacterial communities over the relatively short, one-week incubation. In contrast, 65% of the dissolved organic nitrogen (DON added as an integral part of the ice-algal DOM was consumed, but none of the DON supplied with chl max water was labile. This study underscores the importance of considering DOM sources when investigating or predicting changes in carbon and nitrogen cycling within the

  15. Limno-chemical and microbiology aspects in Uranium Pit Mine Lake (Osamu Utsumi), in Antas and Bortolan reservoirs under the influence of effluent Ore Treatment Unit, Caldas - Minas Gerais State, Brazil

    International Nuclear Information System (INIS)

    Due to high natural radioactivity there in Pocos de Caldas Plateau (Minas Gerais State, Brazil) and the existence of the first uranium mine in Brazil (Pit Mine Osamu Utsumi - Mineral Treatment Unit/Brazilian Nuclear Industries, MTU/BNI), which is characterized by an open-pit mine presents as increased environmental liability the formation of acid mine drainage, this study was conducted to evaluate the limno-chemicals and microbiology aspects (protozooplankton and bacterioplankton) belonging to uranium pit mine lake (PM) and evaluate the possible effects of acid effluents treated and discharged by MTU/BNI in Antas reservoir-AR and downstream of this, the Bortolan reservoir-BR. Besides the realization of abiotic and microbiology analysis of protozooplankton and bacterioplankton; was held standardization and deployment of the Fluorescence 'In Situ' Hybridization (FISH) technical using oligonucleotide probes for extremophile Archaea and Bacteria. According to the results, the PM showed the highest values for the chemical variables, lower pH values, lower protozooplankton density, however, protozooplanktonic high biomass showing the presence of tolerant species in this extreme environment. Antas and Bortolan reservoirs showed differences in the abiotic and biotic variables, AR showed suffer greater interference of acid effluents released at P41point and downstream of this at P14 point, lower protozooplankton biomass, lower bacterial density and pollution characteristics of inorganic sources. Using the FISH technique standard in this study to water bodies evaluated, it was possible to detect the presence of the extremophile bacteria of the Archaea domain in the three water bodies. The results of this study contribute to the knowledge of the pit mine lakes limnology which have become a major concern due to increased mining in the open. (author)

  16. Ocean time-series reveals recurring seasonal patterns of virioplankton dynamics in the northwestern Sargasso Sea.

    Science.gov (United States)

    Parsons, Rachel J; Breitbart, Mya; Lomas, Michael W; Carlson, Craig A

    2012-02-01

    There are an estimated 10(30) virioplankton in the world oceans, the majority of which are phages (viruses that infect bacteria). Marine phages encompass enormous genetic diversity, affect biogeochemical cycling of elements, and partially control aspects of prokaryotic production and diversity. Despite their importance, there is a paucity of data describing virioplankton distributions over time and depth in oceanic systems. A decade of high-resolution time-series data collected from the upper 300 m in the northwestern Sargasso Sea revealed recurring temporal and vertical patterns of virioplankton abundance in unprecedented detail. An annual virioplankton maximum developed between 60 and 100 m during periods of summer stratification and eroded during winter convective mixing. The timing and vertical positioning of this seasonal pattern was related to variability in water column stability and the dynamics of specific picophytoplankton and heterotrophic bacterioplankton lineages. Between 60 and 100 m, virioplankton abundance was negatively correlated to the dominant heterotrophic bacterioplankton lineage SAR11, as well as the less abundant picophytoplankton, Synechococcus. In contrast, virioplankton abundance was positively correlated to the dominant picophytoplankton lineage Prochlorococcus, and the less abundant alpha-proteobacteria, Rhodobacteraceae. Seasonally, virioplankton abundances were highly synchronous with Prochlorococcus distributions and the virioplankton to Prochlorococcus ratio remained remarkably constant during periods of water column stratification. The data suggest that a significant fraction of viruses in the mid-euphotic zone of the subtropical gyres may be cyanophages and patterns in their abundance are largely determined by Prochlorococcus dynamics in response to water column stability. This high-resolution, decadal survey of virioplankton abundance provides insight into the possible controls of virioplankton dynamics in the open ocean. PMID

  17. New and fast method to quantify respiration rates of bacterial and plankton communities in freshwater ecosystems by using optical oxygen sensor spots.

    Science.gov (United States)

    Warkentin, Mareike; Freese, Heike M; Karsten, Ulf; Schumann, Rhena

    2007-11-01

    A new method of respiration rate measurement based on oxygen luminescence quenching in sensor spots was evaluated for the first time for aquatic bacterial communities. The commonly used Winkler and Clark electrode methods to quantify oxygen concentration both require long incubation times, and the latter additionally causes signal drift due to oxygen consumption at the cathode. The sensor spots proved to be advantageous over those methods in terms of precise and quick oxygen measurements in natural bacterial communities, guaranteeing a respiration rate estimate during a time interval short enough to neglect variations in organism composition, abundance, and activity. Furthermore, no signal drift occurs during measurements, and respiration rate measurements are reliable even at low temperatures and low oxygen consumption rates. Both a natural bacterioplankton sample and a bacterial isolate from a eutrophic river were evaluated in order to optimize the new method for aquatic microorganisms. A minimum abundance of 2.2 x 10(6) respiring cells ml(-1) of a bacterial isolate was sufficient to obtain a distinct oxygen depletion signal within 20 min at 20 degrees C with the new oxygen sensor spot method. Thus, a culture of a bacterial isolate from a eutrophic river (OW 144; 20 x 10(6) respiring bacteria ml(-1)) decreased the oxygen saturation about 8% within 20 min. The natural bacterioplankton sample respired 2.8% from initially 94% oxygen-saturated water in 30 min. During the growth season in 2005, the planktonic community of a eutrophic river consumed between 0.7 and 15.6 micromol O(2) liter(-1) h(-1). The contribution of bacterial respiration to the total plankton community oxygen consumption varied seasonally between 11 and 100%. PMID:17766446

  18. Physiological profiling of indigenous aquatic microbial communities to determine toxic effects of metals

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, R.M.; Colwell, F.S. [Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States); Garland, J.L. [Dynamac, Kennedy Space Center, FL (United States)

    1997-11-01

    Conventional bioassays for environmental assessment frequently rely on nonindigenous single species. The authors employed an assay in which whole environmental samples were distinguished by the ability of the native heterotrophic microbial communities to oxidize 95 different sole carbon sources generating a community-level physiological profile (CLPP). The average metabolic response (AMR) to the 95 variables defining the CLPP was used in laboratory bioassay studies with copper to construct dose-response curves over several different periods of exposure: 1 h (acute), 1 d, 2 d, and 4 d. The acute dose-response of Snake River bacterioplankton communities measured by AMR was compared to the dose-response of Photobacterium phosphoreum (used in the Microtox test) and a proprietary mixed consortia (used in the Polytox test). In laboratory bioassay studies, CLPP, AMR exhibited acute dose-response behavior over a greater range in copper concentrations and with less variability (per dose) than Microtox and Polytox. The acute sensitivity of CLPP AMR to copper was roughly equal to Microtox and much greater than Polytox. After a longer exposure (1 d) to copper, Snake River communities became more sensitive to copper but no additional effect was observed when the exposure was increases to 2 and 4 d. Snake River communities pre-exposed to copper (1 mg/L) for 4 d prior to acute dose-response experiments showed no difference in AMR with respect to doses up to 10 mg/L, indicating the ability of the assay to detect adaptation. Several metal-contaminated streams in Idaho were used to field validate the CLPP approach for detecting impacts of metals in the environment. The response profiles of the bacterioplankton from two downstream sites receiving metal laden mine drainage were compared to those from reference sites upstream and further downstream of the location receiving the mine drainage.

  19. Limno-chemical and microbiology aspects in Uranium Pit Mine Lake (Osamu Utsumi), in Antas and Bortolan reservoirs under the influence of effluent Ore Treatment Unit, Caldas - Minas Gerais State, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ronqui, Leilane B.; Nasciment, Marcos R.L. do; Roque, Claudio V.; Bruschi, Armando; Borba Junior, Palvo J.; Nascimento, Heliana A. F. do, E-mail: leilanebio@yahoo.com.br, E-mail: pmarcos@cnen.gov.br, E-mail: cvroque@cnen.gov.br, E-mail: abruschi@cnen.gov.br, E-mail: jouber_borba@hotmail.com, E-mail: hazevedo@cnen.gov.br [Comissao Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas; Almeida, Tito C.M. de, E-mail: titoalmeida2008@gmail.com [Universidade do Vale do Itajai (CTT-Mar/UNIVALI), SC (Brazil). Centro de Ciencias Tecnologicas da Terra e do Mar

    2013-07-01

    Due to high natural radioactivity there in Pocos de Caldas Plateau (Minas Gerais State, Brazil) and the existence of the first uranium mine in Brazil (Pit Mine Osamu Utsumi - Mineral Treatment Unit/Brazilian Nuclear Industries, MTU/BNI), which is characterized by an open-pit mine presents as increased environmental liability the formation of acid mine drainage, this study was conducted to evaluate the limno-chemicals and microbiology aspects (protozooplankton and bacterioplankton) belonging to uranium pit mine lake (PM) and evaluate the possible effects of acid effluents treated and discharged by MTU/BNI in Antas reservoir-AR and downstream of this, the Bortolan reservoir-BR. Besides the realization of abiotic and microbiology analysis of protozooplankton and bacterioplankton; was held standardization and deployment of the Fluorescence 'In Situ' Hybridization (FISH) technical using oligonucleotide probes for extremophile Archaea and Bacteria. According to the results, the PM showed the highest values for the chemical variables, lower pH values, lower protozooplankton density, however, protozooplanktonic high biomass showing the presence of tolerant species in this extreme environment. Antas and Bortolan reservoirs showed differences in the abiotic and biotic variables, AR showed suffer greater interference of acid effluents released at P41point and downstream of this at P14 point, lower protozooplankton biomass, lower bacterial density and pollution characteristics of inorganic sources. Using the FISH technique standard in this study to water bodies evaluated, it was possible to detect the presence of the extremophile bacteria of the Archaea domain in the three water bodies. The results of this study contribute to the knowledge of the pit mine lakes limnology which have become a major concern due to increased mining in the open. (author)

  20. Carbon dynamics in highly heterotrophic subarctic thaw ponds

    Directory of Open Access Journals (Sweden)

    T. Roiha

    2015-07-01

    Full Text Available Global warming has accelerated the formation of permafrost thaw ponds in several subarctic and arctic regions. These ponds are net heterotrophic as evidenced by their greenhouse gas (GHG supersaturation levels (CO2 and CH4, and generally receive large terrestrial carbon inputs from the thawing and eroding permafrost. We measured seasonal and vertical variations in the concentration and type of dissolved organic matter (DOM in five subarctic thaw (thermokarst ponds in northern Quebec, and explored how environmental gradients influenced heterotrophic and phototrophic biomass and productivity. Late winter DOM had low aromaticity indicating reduced inputs of terrestrial carbon, while the high concentration of dissolved organic carbon (DOC suggests that some production of non-chromophoric dissolved compounds by the microbial food web took place under the ice cover. Summer DOM had a strong terrestrial signature, but was also characterized with significant inputs of algal-derived carbon, especially at the pond surface. During late winter, bacterial production was low (maximum of 0.8 mg C m−3 d−1 and was largely based on free-living bacterioplankton (58 %. Bacterial production in summer was high (up to 58 mg C m−3 d−1, dominated by particle-attached bacteria (67 %, and strongly correlated to the amount of terrestrial carbon. Primary production was restricted to summer surface waters due to strong light limitation deeper in the water column or in winter. The phototrophic biomass was equal to the heterotrophic biomass, but as the algae were mostly composed of mixotrophic species, most probably they used bacteria rather than solar energy in such shaded ponds. According to the δ13C analyses, non-algal carbon supported 51 % of winter and 37 % of summer biomass of the phantom midge larvae, Chaoborus sp., that are at the top of the trophic chain. Our results point to a strong heterotrophic energy pathway in these thaw pond ecosystems, where

  1. More, smaller bacteria in response to ocean's warming?

    KAUST Repository

    Moran, Xose Anxelu G.

    2015-06-10

    Heterotrophic bacteria play a major role in organic matter cycling in the ocean. Although the high abundances and relatively fast growth rates of coastal surface bacterioplankton make them suitable sentinels of global change, past analyses have largely overlooked this functional group. Here, time series analysis of a decade of monthly observations in temperate Atlantic coastal waters revealed strong seasonal patterns in the abundance, size and biomass of the ubiquitous flow-cytometric groups of low (LNA) and high nucleic acid (HNA) content bacteria. Over this relatively short period, we also found that bacterioplankton cells were significantly smaller, a trend that is consistent with the hypothesized temperature-driven decrease in body size. Although decadal cell shrinking was observed for both groups, it was only LNA cells that were strongly coherent, with ecological theories linking temperature, abundance and individual size on both the seasonal and interannual scale. We explain this finding because, relative to their HNA counterparts, marine LNA bacteria are less diverse, dominated by members of the SAR11 clade. Temperature manipulation experiments in 2012 confirmed a direct effect of warming on bacterial size. Concurrent with rising temperatures in spring, significant decadal trends of increasing standing stocks (3% per year) accompanied by decreasing mean cell size (-1% per year) suggest a major shift in community structure, with a larger contribution of LNA bacteria to total biomass. The increasing prevalence of these typically oligotrophic taxa may severely impact marine foodwebs and carbon fluxes by an overall decrease in the efficiency of the biological pump. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  2. Underwater application of quantitative PCR on an ocean mooring.

    Directory of Open Access Journals (Sweden)

    Christina M Preston

    Full Text Available The Environmental Sample Processor (ESP is a device that allows for the underwater, autonomous application of DNA and protein probe array technologies as a means to remotely identify and quantify, in situ, marine microorganisms and substances they produce. Here, we added functionality to the ESP through the development and incorporation of a module capable of solid-phase nucleic acid extraction and quantitative PCR (qPCR. Samples collected by the instrument were homogenized in a chaotropic buffer compatible with direct detection of ribosomal RNA (rRNA and nucleic acid purification. From a single sample, both an rRNA community profile and select gene abundances were ascertained. To illustrate this functionality, we focused on bacterioplankton commonly found along the central coast of California and that are known to vary in accordance with different oceanic conditions. DNA probe arrays targeting rRNA revealed the presence of 16S rRNA indicative of marine crenarchaea, SAR11 and marine cyanobacteria; in parallel, qPCR was used to detect 16S rRNA genes from the former two groups and the large subunit RuBisCo gene (rbcL from Synecchococcus. The PCR-enabled ESP was deployed on a coastal mooring in Monterey Bay for 28 days during the spring-summer upwelling season. The distributions of the targeted bacterioplankon groups were as expected, with the exception of an increase in abundance of marine crenarchaea in anomalous nitrate-rich, low-salinity waters. The unexpected co-occurrence demonstrated the utility of the ESP in detecting novel events relative to previously described distributions of particular bacterioplankton groups. The ESP can easily be configured to detect and enumerate genes and gene products from a wide range of organisms. This study demonstrated for the first time that gene abundances could be assessed autonomously, underwater in near real-time and referenced against prevailing chemical, physical and bulk biological conditions.

  3. Underwater application of quantitative PCR on an ocean mooring.

    Science.gov (United States)

    Preston, Christina M; Harris, Adeline; Ryan, John P; Roman, Brent; Marin, Roman; Jensen, Scott; Everlove, Cheri; Birch, James; Dzenitis, John M; Pargett, Douglas; Adachi, Masao; Turk, Kendra; Zehr, Jonathon P; Scholin, Christopher A

    2011-01-01

    The Environmental Sample Processor (ESP) is a device that allows for the underwater, autonomous application of DNA and protein probe array technologies as a means to remotely identify and quantify, in situ, marine microorganisms and substances they produce. Here, we added functionality to the ESP through the development and incorporation of a module capable of solid-phase nucleic acid extraction and quantitative PCR (qPCR). Samples collected by the instrument were homogenized in a chaotropic buffer compatible with direct detection of ribosomal RNA (rRNA) and nucleic acid purification. From a single sample, both an rRNA community profile and select gene abundances were ascertained. To illustrate this functionality, we focused on bacterioplankton commonly found along the central coast of California and that are known to vary in accordance with different oceanic conditions. DNA probe arrays targeting rRNA revealed the presence of 16S rRNA indicative of marine crenarchaea, SAR11 and marine cyanobacteria; in parallel, qPCR was used to detect 16S rRNA genes from the former two groups and the large subunit RuBisCo gene (rbcL) from Synecchococcus. The PCR-enabled ESP was deployed on a coastal mooring in Monterey Bay for 28 days during the spring-summer upwelling season. The distributions of the targeted bacterioplankon groups were as expected, with the exception of an increase in abundance of marine crenarchaea in anomalous nitrate-rich, low-salinity waters. The unexpected co-occurrence demonstrated the utility of the ESP in detecting novel events relative to previously described distributions of particular bacterioplankton groups. The ESP can easily be configured to detect and enumerate genes and gene products from a wide range of organisms. This study demonstrated for the first time that gene abundances could be assessed autonomously, underwater in near real-time and referenced against prevailing chemical, physical and bulk biological conditions. PMID:21829630

  4. Carbon dynamics in highly heterotrophic subarctic thaw ponds

    Science.gov (United States)

    Roiha, T.; Laurion, I.; Rautio, M.

    2015-07-01

    Global warming has accelerated the formation of permafrost thaw ponds in several subarctic and arctic regions. These ponds are net heterotrophic as evidenced by their greenhouse gas (GHG) supersaturation levels (CO2 and CH4), and generally receive large terrestrial carbon inputs from the thawing and eroding permafrost. We measured seasonal and vertical variations in the concentration and type of dissolved organic matter (DOM) in five subarctic thaw (thermokarst) ponds in northern Quebec, and explored how environmental gradients influenced heterotrophic and phototrophic biomass and productivity. Late winter DOM had low aromaticity indicating reduced inputs of terrestrial carbon, while the high concentration of dissolved organic carbon (DOC) suggests that some production of non-chromophoric dissolved compounds by the microbial food web took place under the ice cover. Summer DOM had a strong terrestrial signature, but was also characterized with significant inputs of algal-derived carbon, especially at the pond surface. During late winter, bacterial production was low (maximum of 0.8 mg C m-3 d-1) and was largely based on free-living bacterioplankton (58 %). Bacterial production in summer was high (up to 58 mg C m-3 d-1), dominated by particle-attached bacteria (67 %), and strongly correlated to the amount of terrestrial carbon. Primary production was restricted to summer surface waters due to strong light limitation deeper in the water column or in winter. The phototrophic biomass was equal to the heterotrophic biomass, but as the algae were mostly composed of mixotrophic species, most probably they used bacteria rather than solar energy in such shaded ponds. According to the δ13C analyses, non-algal carbon supported 51 % of winter and 37 % of summer biomass of the phantom midge larvae, Chaoborus sp., that are at the top of the trophic chain. Our results point to a strong heterotrophic energy pathway in these thaw pond ecosystems, where bacterioplankton dominates

  5. Heterotrophic bacterial responses to the winter–spring phytoplankton bloom in open waters of the NW Mediterranean

    KAUST Repository

    Gomes, Ana

    2014-12-03

    The response of planktonic heterotrophic prokaryotes to the NW Mediterranean winter–spring offshore phytoplankton bloom was assessed in 3 cruises conducted in March, April–May and September 2009. Bulk measurements of phytoplankton and bacterioplankton biomass and production were complemented with an insight into bacterial physiological structure by single-cell analysis of nucleic acid content [low (LNA) vs. high (HNA)] and membrane integrity (“Live” vs. “Dead” cells). Bacterial production empirical conversion factors (0.82±0.25 SE kg C mol leucine−1) were almost always well below the theoretical value. Major differences in most microbial variables were found among the 3 periods, which varied from extremely high phytoplankton biomass and production during the bloom in March (>1 g C m−2 d−1 primary production) to typically oligotrophic conditions during September stratification (<200 mg C m−2 d−1). In both these periods bacterial production was ~30 mg C m−2 d−1 while very large bacterial production (mean 228, with some stations exceeding 500 mg C m−2 d−1) but low biomass was observed during the April–May post-bloom phase. The contribution of HNA (30–67%) and “Live” cells (47–97%) were temporally opposite in the study periods, with maxima in March and September, respectively. Different relationships were found between physiological structure and bottom-up variables, with HNA bacteria apparently more responsive to phytoplankton only during the bloom, coinciding with larger average cell sizes of LNA bacteria. Moderate phytoplankton–bacterioplankton coupling of biomass and activity was only observed in the bloom and post-bloom phases, while relationships between both compartments were not significant under stratification. With all data pooled, bacteria were only weakly bottom-up controlled. Our analyses show that the biomass and production of planktonic algae and bacteria followed opposite paths in the transition from bloom to

  6. Culture-based Identification Of Microcystin-Degrading Bacteria In the Sandusky Bay and Maumee Bay of Lake Erie

    Science.gov (United States)

    Ormiston, A.; Mou, X.

    2012-12-01

    Harmful cyanobacteria blooms (cyanoHABs) are a serious issue that affects wildlife, human health, recreation and local economics worldwide. CyanoHABs produce cyanotoxins, such as microcystins (MCs) that lead to skin irritation, illness and liver tumors. Bacterially mediated degradation of MCs plays a key role to transform these toxic substrates to less harmful metabolites in natural environments. However, only a few Sphingomonos species have been isolated for degradation of MCs and many of which are from other habitats such as water plants. This project aims to isolate and identify bacteria that can degrade MC-LR and MC-RR, two major forms of MCs found during cyanoHABs in Lake Erie. Water samples were collected from the surface of Sandusky Bay and Maumee Bay of Lake Erie and immediately filtered through 3.0 -μm-pore-size membrane filters to obtain bacterioplankton fraction. The filtrates were amended with excessive inorganic nitrogen and phosphorus compounds and incubated in the dark for a week to purposely establish a carbon-limited condition. Afterwards, enrichment microcosms were established in flasks filled with pre-incubated bacterioplankton and single MC compounds (final concentration 10 μM). Once cell growth was confirmed by flow cytometry-based cell counting, bacterial cells in enriched microcosms were transferred onto solid surfaces, i.e., GFF filter and noble agar for colony isolation. Obtained single colonies were inoculated in defined liquid media with MCs as single carbon source. DNA was extracted from each purified isolate and analyzed by restriction fragment length polymorphism analysis (RFLP). A total of 18 different RFLP banding patterns were found, indicating MC-degrading bacteria may be heterogeneous in studied water samples. 16S rRNA genes of selected bacterial isolates were PCR amplified and sequenced for taxonomic identification. Our results demonstrated that MCs can be degraded by multiple bacterial species in Lake Erie. Future directions

  7. SELF-PURIFICATION OF THE DNIPROVS’KE RESERVOIR AS A LEADING FORMING FACTOR FOR THE ECOLOGICALLY SAFE HABITAT OF FISHES

    Directory of Open Access Journals (Sweden)

    А. Dvoretsky

    2014-12-01

    Full Text Available Purpose. To study the development of the water quality of the Dniprovs’ke reservoir, which is a water of body of complex including fisheries importance and is characterized by an increased anthropogenic pressure as a result of the processes of the toxification and self-purification determined based on toxicity index (Іt. Methodology. We used the methods of bioindication (determination of the number and biomass of phytoplankton and heterotrophic bacterioplankton, biotesting (Іt determinaiton with the aid of Daphnia magna, hydrochemistry (determination of main trophic-saprobiological parameters of water quality as well as the correlation analysis of these parameters. Findings. According to the 2012 data, tropho-saprobiologic, algological, microbiological parameters and toxicity index as an integral parameter were analyzed concerning to water quality. Regularities of dynamics and relationship of the indexes were studied. The environmental assessment of water quality of the most polluted upper part of the Dniprovs’ke reservoirs was carried out for each of the parameters studied: in areas where agro-industrial wastes enter, water is classified as «moderately polluted» – «very dirty». The data testify to strong local water pollution of the reservoir and a good renewable ability of the ecosystem. It was shown that in conditions of human toxification the adequate response concerning water quality gives the toxicity index as an integral indicator of toxification and self-purification processes. The dual role of phytoplankton and heterotrophic bacterioplankton in formation of water quality of the anthropogenically loaded reservoir was revealed: these components are involved in the processes of self-purification or toxification in accordance with periods of microalgae development during the season. This is displayed in corresponding changes of TI and the correlation coefficient. It was found that the self-cleaning of the reservoir is a major

  8. Effect of permafrost thawing on the organic carbon and metal speciation

    Science.gov (United States)

    Pokrovsky, Oleg; Shirokova, Liudmila; Kirpotin, Sergey; Dupre, Bernard

    2010-05-01

    Ongoing processes of the permafrost thawing in Western Siberia are likely to increase the surface of water reservoirs via forming so-called thermokarst (thaw) lakes, mobilizing the organic carbon from the soil pool to the rivers and, finally, to the ocean, and also modifying the fluxes of methane and CO2 to the atmosphere. In order to better understand the mechanisms of carbon mobilization and organic matter biodegradation during permafrost thawing and to establish the link between the organic carbon, microbial activity and geochemistry of major and trace elements in forming thermokarstic lakes, we performed a comparative multidisciplinary study on the biogeochemistry of organic carbon and bacterioplankton in lakes located in the northern part of Western Siberia. Towards this goal, fifteen lakes and three surface streams draining neogenic deposits on continuous permafrost ground of the Urengoy region. There is a sequence of ecosystem stages during evolution from peat thawing in depressions and palsa degradation due to permafrost subsidence in small ponds to large, km - size lakes subject to drainage and, finally, the khasyrei formation (remaining central parts of drained lakes). In the chronosequence of lake formation, there is a clear decrease of the relative proportion of bacterioplankton is the main process controlling the chemical composition of thaw lakes. We also show that, regardless of the stage of the thaw lake evolution, from small forming pond to large lake subjected to draining, there is always significant degradation of dissolved organic matter accompanied by permanent CO2 flux to the atmosphere. Since all lakes on the permafrost ground have thermokarst origin and thus similar to those studied in this work, one calculate the minimal flux of the CO2 to the atmosphere from 792,000 km² of all permafrost lake area, given that 65.5% of lakes to the north of the Arctic Circle occur in Russia. The annual input of CO2 from the earth surface to the atmosphere

  9. Vertical and longitudinal gradients in HNA-LNA cell abundances and cytometric characteristics in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    F. Van Wambeke

    2011-07-01

    Full Text Available Heterotrophic bacterioplankton abundance and production were investigated with depth (down to bathypelagic layers and with longitude (from 4.9° E to 32.7° E along a cruise track across the Mediterranean Sea in early summer 2008. Abundances and flow cytometric characteristics (green fluorescence and side scatter signals of high nucleic acid (HNA and low nucleic acid (LNA bacterial cells were determined using flow cytometry. Contrary to what is generally observed, the relative importance of HNA cells, as a percent of total cells, (%HNA, range 30–69 % was inversely related to bacterial production (range 0.15–44 ng C l−1 h−1 although the negative relation was weak (log–log regression r2=0.19. The %HNA as well as the mean side scatter of HNA group increased significantly with depth in the meso and bathypelagic layers. Vertical stratification played an important role in influencing the distribution and characteristics of bacterial cells especially with regard to layers located above, within or below the deep chlorophyll maximum. Within a given layer, the relationships between the flow cytometric characteristics and environmental variables such as chlorophyll-a, nutrients or bacterial production changed. Overall, the relationships between HNA and LNA cells and environmental parameters differed vertically more than longitudinally.

  10. Water chemistry and plankton composition in the mixing zone of the Selenga River with Lake Baikal

    Science.gov (United States)

    Tomberg, Irina; Sorokovikova, larisa; Popovskaya, Galina; Belykh, Olga; Bashenkhaeva, Nadya; Parfenova, Valentina

    2014-05-01

    Seasonal and inter-annual variations of chemical components, bacterio- and phytoplankton and autotrophic picoplankton (APP) were studied in the distributaries of the Selenga River, Selenga shallow waters (Selenga shoal) and Lake Baikal for 2003-2013. Major variations in the chemical composition of river waters were recorded at a distance of 1-3 km off the mouths of the Selenga River distributaries (mixing zone). The total quantity of major ions and plankton composition and abundance served as indicators to distinguish between river and lake waters. Phytoplankton concentration was high in the mixing zone and caused the reduction of nutrients in this area. Changes in species composition of phytoplankton, APP, dominant groups of bacterioplankton were observed in the Selenga shoal. River phytoplankton prevailed near the mouths of distributaries, in the mixing zone these were replaced by lake species, and at a distance of 7 km offshore phytoplankton composition was typical of Lake Baikal. Organotrophic microorganisms dominated in the Selenga River water. In the mixing zone, all bacterial groups were represented in equal proportions. Oligotrophic and psychrotolerant bacteria prevailed in Lake Baikal. As the distance from the river delta increased, phycocyanin-rich picocyanobacteria were replaced by phycoerythrin-rich picocyanobacteria and the contribution of picoplankton biomass to total phytoplankton biomass was raised. Near the mouth of distributaries, APP biomass was 5 times lower than the phytoplankton biomass whilst at a distance of 7 km it was 2 times higher than typical values for Baikal phytoplankton.

  11. Zooplankton community composition of high mountain lakes in the Tatra Mts., the Alps in North Tyrol, and Scotland: relationship to pH, depth, organic carbon, and chlorophyll-a concentration

    Directory of Open Access Journals (Sweden)

    Skála Ivan

    2015-10-01

    Full Text Available The European EMERGE (European Mountain lake Ecosystems: Regionalisation, diaGnostic & socio-economic Evaluation project was a survey of high mountain lakes (above treeline across Europe using unified methods of sampling and analysis. The sampling was carried out in summer or autumn 2000, and comprised biological samples, and samples for chemical analysis. Data from three lake districts are used in this paper: the Tatra Mts. in Slovakia and Poland (45 lakes, the Alps in Tyrol in Austria (22 lakes, and Scotland (30 lakes. As it is shown by multiple regression analysis, DTOC (dissolved or total organic carbon is the key variable for most groups of zooplankton. With increasing DTOC and mostly with chlorophyll-a decreasing, pH increasing and depth decreasing, macrofitrators with coarse filter meshes are replaced by microfiltrators with fine filter meshes. Higher DTOC may increase bacterioplankton production and advantage species able to consume bacteria (microfiltrators. Other zooplankton species also differ in their preference for DTOC, chlorophyll-a, pH and depth, but DTOC being positively correlated with chlorophyll-a and pH positively correlated with depth. It may be caused by their different preference for food quality in terms of C:P ratio.

  12. Heterologous expression of proteorhodopsin enhances H2 production in Escherichia coli when endogenous Hyd-4 is overexpressed.

    Science.gov (United States)

    Kuniyoshi, Taís M; Balan, Andrea; Schenberg, Ana Clara G; Severino, Divinomar; Hallenbeck, Patrick C

    2015-07-20

    Proteorhodopsin (PR) is a light harvesting protein widely distributed among bacterioplankton that plays an integral energetic role in a new pathway of marine light capture. The conversion of light into chemical energy in non-chlorophyll-based bacterial systems could contribute to overcoming thermodynamic and metabolic constraints in biofuels production. In an attempt to improve biohydrogen production yields, H2 evolution catalyzed by endogenous hydrogenases, Hyd-3 and/or Hyd-4, was measured when recombinant proteorhodopsin (PR) was concomitantly expressed in Escherichia coli cells. Higher amounts of H2 were obtained with recombinant cells in a light and chromophore dependent manner. This effect was only observed when HyfR, the specific transcriptional activator of the hyf operon encoding Hyd-4 was overexpressed in E. coli, suggesting that an excess of protons generated by PR activity could increase hydrogen production by Hyd-4 but not by Hyd-3. Although many of the subunits of Hyd-3 and Hyd-4 are very similar, Hyd-4 possesses three additional proton-translocating NADH-ubiquinone oxidoreductase subunits, suggesting that it is dependent upon ΔμH(+). Altogether, these results suggest that protons generated by proteorhodopsin in the periplasm can only enhance hydrogen production by hydrogenases with associated proton translocating subunits. PMID:25913175

  13. Low-resolution characterization of the 3D structure of the Euglena gracilis photoreceptor

    International Nuclear Information System (INIS)

    This paper deals with the first characterization of the structure of the photoreceptive organelle of the unicellular alga Euglena gracilis (Euglenophyta). This organelle has a three-dimensional organization consisting of up to 50 closely stacked membrane lamellae. Ionically induced unstacking of the photoreceptor lamellae revealed ordered arrays well suited to structural analysis by electron microscopy and image analysis, which ultimately yielded a low-resolution picture of the structure. Each lamella is formed by the photoreceptive membrane protein of the cell assembled within the membrane layer in a hexagonal lattice. The first order diffraction spots in the calculated Fourier transform reveals the presence of 6-fold symmetrized topography (better resolution about 90 A). The 2D and 3D structural data are very similar with those recently published on proteorodopsin, a membrane protein used by marine bacterio-plankton as light-driven proton pump. In our opinion these similarity indicate that a photoreceptive protein belonging to the same superfamily of proteorodopsin could form the Euglena photoreceptor

  14. The influence of zooplankton enrichment on the microbial loop in a shallow, eutrophic lake.

    Science.gov (United States)

    Zingel, Priit; Agasild, Helen; Karus, Katrit; Kangro, Kersti; Tammert, Helen; Tõnno, Ilmar; Feldmann, Tõnu; Nõges, Tiina

    2016-02-01

    With increasing primary productivity, ciliates may become the most important members of the microbial loop and form a central linkage in the transformation of microbial production to upper trophic levels. How metazooplankters, especially copepods, regulate ciliate community structure in shallow eutrophic waters is not completely clear. We carried out mesocosm experiments with different cyclopoid copepod enrichments in a shallow eutrophic lake to examine the responses of ciliate community structure and abundance to changes in cyclopoid copepod biomass and to detect any cascading effects on bacterioplankton and edible phytoplankton. Our results indicate that an increase in copepod zooplankton biomass favours the development of small-sized bacterivorous ciliates. This effect is unleashed by the decline of predaceous ciliate abundance, which would otherwise graze effectively on the small-sized ciliates. The inverse relationship between crustacean zooplankton and large predaceous ciliates is an important feature adjusting not only the structure of the ciliate community but also the energy transfer between meta- and protozooplankton. Still we could not detect any cascading effects on bacterio- or phytoplankton that would be caused by the structural changes in the ciliate community. PMID:26555735

  15. Indicators of early successional trends in environmental condition and community function in constructed wetlands of the Athabasca Oilsands region

    International Nuclear Information System (INIS)

    This presentation reported on a study that compared interannual environmental variation in post-mining Athabasca oil sands landscapes. In particular, it compared biological, ecotoxicological and carbon dynamic aspects of sixteen 5 to 30 year old wetlands with different ages, reclamation materials and stockpiled surface materials such as peat. In addition to determining carbon fluxes, standing stocks of hydrocarbons were measured along with organic substrate, bacterioplankton, phytoplankton, biofilm, macrophytes, litter, zoobenthos, and aquatic insect emergence. Gas fluxes, microbial, plant, zoobenthic, amphibian, and tree swallow nestling production, and stable isotope signatures were used to determine carbon pathways, fluxes and budgets. Coarse taxon richness in reference wetlands reached an asymptote in 5 to 7 years. Richness, composition and emergent plant cover of oilsands-affected wetlands converged over a 15 to 20 year period with reference wetland patterns. The development of emergent but not submergent plant cover and associated biota accelerated with the addition of peat. Water chemistry was found to be more important than sediment in terms of regulating submergent biological properties. The study showed that the most important regulator of community composition may be residual salinity. Compared to more temperate biomes, the successional trends were slower.

  16. Temperature dependences of growth rates and carrying capacities of marine bacteria depart from metabolic theoretical predictions.

    Science.gov (United States)

    Huete-Stauffer, Tamara Megan; Arandia-Gorostidi, Nestor; Díaz-Pérez, Laura; Morán, Xosé Anxelu G

    2015-10-01

    Using the metabolic theory of ecology (MTE) framework, we evaluated over a whole annual cycle the monthly responses to temperature of the growth rates (μ) and carrying capacities (K) of heterotrophic bacterioplankton at a temperate coastal site. We used experimental incubations spanning 6ºC with bacterial physiological groups identified by flow cytometry according to membrane integrity (live), nucleic acid content (HNA and LNA) and respiratory activity (CTC+). The temperature dependence of μ at the exponential phase of growth was summarized by the activation energy (E), which was variable (-0.52 to 0.72 eV) but followed a seasonal pattern, only reaching the hypothesized value for aerobic heterotrophs of 0.65 eV during the spring bloom for the most active bacterial groups (live, HNA, CTC+). K (i.e. maximum experimental abundance) peaked at 4 × 10(6) cells mL(-1) and generally covaried with μ but, contrary to MTE predictions, it did not decrease consistently with temperature. In the case of live cells, the responses of μ and K to temperature were positively correlated and related to seasonal changes in substrate availability, indicating that the responses of bacteria to warming are far from homogeneous and poorly explained by MTE at our site. PMID:26362925

  17. Effects of Dispersal and Initial Diversity on the Composition and Functional Performance of Bacterial Communities

    Science.gov (United States)

    Zha, Yinghua; Berga, Mercè; Comte, Jérôme; Langenheder, Silke

    2016-01-01

    Natural communities are open systems and consequently dispersal can play an important role for the diversity, composition and functioning of communities at the local scale. It is, however, still unclear how effects of dispersal differ depending on the initial diversity of local communities. Here we implemented an experiment where we manipulated the initial diversity of natural freshwater bacterioplankton communities using a dilution-to-extinction approach as well as dispersal from a regional species pool. The aim was further to test whether dispersal effects on bacterial abundance and functional parameters (average community growth rates, respiration rates, substrate utilisation ability) differ in dependence of the initial diversity of the communities. First of all, we found that both initial diversity and dispersal rates had an effect on the recruitment of taxa from a regional source, which was higher in communities with low initial diversity and at higher rates of dispersal. Higher initial diversity and dispersal also promoted higher levels of richness and evenness in local communities and affected, both, separately or interactively, the functional performance of communities. Our study therefore suggests that dispersal can influence the diversity, composition and functioning of bacterial communities and that this effect may be enhanced if the initial diversity of communities is depleted. PMID:27182596

  18. Dilution-to-extinction culturing of SAR11 members and other marine bacteria from the Red Sea

    KAUST Repository

    Mohamed, Roslinda B.

    2013-12-01

    Life in oceans originated about 3.5 billion years ago where microbes were the only life form for two thirds of the planet’s existence. Apart from being abundant and diverse, marine microbes are involved in nearly all biogeochemical processes and are vital to sustain all life forms. With the overgrowing number of data arising from culture-independent studies, it became necessary to improve culturing techniques in order to obtain pure cultures of the environmentally significant bacteria to back up the findings and test hypotheses. Particularly in the ultra-oligotrophic Red Sea, the ubiquitous SAR11 bacteria has been reported to account for more than half of the surface bacterioplankton community. It is therefore highly likely that SAR11, and other microbial life that exists have developed special adaptations that enabled them to thrive successfully. Advances in conventional culturing have made it possible for abundant, unculturable marine bacteria to be grown in the lab. In this study, we analyzed the effectiveness of the media LNHM and AMS1 in isolating marine bacteria from the Red Sea, particularly members of the SAR11 clade. SAR11 strains obtained from this study AMS1, and belonged to subgroup 1a and phylotype 1a.3. We also obtained other interesting strains which should be followed up with in the future. In the long run, results from this study will enhance our knowledge of the pelagic ecosystem and allow the impacts of rising temperatures on marine life to be understood.

  19. Distribution and diversity of Prochlorococcus ecotypes in the Red Sea

    KAUST Repository

    Shibl, Ahmed A.

    2014-06-19

    Photosynthetic prokaryotes of the genus Prochlorococcus play a major role in global primary production in the world\\'s oligotrophic oceans. A recent study on pelagic bacterioplankton communities in the northern and central Red Sea indicated that the predominant cyanobacterial 16S rRNA gene sequence types were from Prochlorococcus cells belonging to a high-light-adapted ecotype (HL II). In this study, we analyzed microdiversity of Prochlorococcus sp. at multiple depths within and below the euphotic zone in the northern, central, and southern regions of the Red Sea, as well as in surface waters in the same locations, but in a different season. Prochlorococcus dominated the communities in clone libraries of the amplified 16S-23S rRNA internal transcribed spacer (ITS) region. Almost no differences were found between samples from coastal or open-water sites, but a high diversity of Prochlorococcus ecotypes was detected at 100-meter depth in the water column. In addition, an unusual dominance of HL II-related sequences was observed in deeper waters. Our results indicate that the Red Sea harbors diverse Prochlorococcus lineages, but no novel ecotypes, despite its unusual physicochemical properties. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  20. Biological cycling of nitrogen in a Rocky Mountain alpine lake, with emphasis on the physiological and ecological effects of acidification

    International Nuclear Information System (INIS)

    This study examined nitrogen cycling interactions occurring among the heterotrophic and autotrophic plankton of a softwater, oligotrophic alpine lake. Its major objectives were (1) to compare the influences of internal (regenerative) and external nitrogen supply processes on watercolumn primary production, (2) to identify the food web components contributing most to regenerative and assimilative fluxes of nitrogen, and (3) to evaluate the sensitivity of the limnetic nitrogen cycle to lake acidification. Field and laboratory experiments were based on isotopic tracer (15N, 14C, 3H) methodologies plankton size-fractionation and metabolic inhibitor techniques, and short-term bioassay procedures; supporting data were gathered on lake physicochemical and biological properties. Measured aqueous nutrient concentrations, the results of 14CO2-based snowmelt and nutrient enrichment bioassays, and physiological indicators of algal nutrient status collectively demonstrated that phytoplankton nitrogen demand greatly exceeded nitrogen supply. Both NH4+ and NO3- were quantitatively important forms of assimilatable nitrogen under ambient conditions. Mass balance considerations indicated that within-lake biogeochemical processes constituted a net sink for NO3-, whereas NH4+ production and consumption rates were approximately in balance on an ecosystem scale. Water-column regenerative and assimilative fluxes of NH4+ were strongly correlated. Meta- and protozooplankton were the principal sources of regenerated NH4+; heterotrophic bacterioplankton were net consumers of NH4+. Experimental reductions in metazooplankton populations markedly enhanced rates of NH4+ regeneration

  1. Diversity of Bacteroidetes in high-altitude saline evaporitic basins in northern Chile

    Science.gov (United States)

    Dorador, Cristina; Meneses, Daniela; Urtuvia, Viviana; Demergasso, Cecilia; Vila, Irma; Witzel, Karl-Paul; Imhoff, Johannes F.

    2009-06-01

    The phylum Bacteroidetes represents one of the most abundant bacterial groups of marine and freshwater bacterioplankton. We investigated the diversity of Bacteroidetes in water and sediment samples from three evaporitic basins located in the highlands of northern Chile. We used both 16S rRNA gene clone libraries created with targeted Bacteroidetes-specific primers and separation of specifically amplified gene fragments by denaturing gradient gel electrophoresis (DGGE). DGGE analysis revealed a reduced richness of these organisms in samples from Salar de Huasco (two to four DGGE bands) increasing in Salar de Ascotán (two to seven DGGE bands) and Laguna Tebenquiche at Salar de Atacama (four to eight DGGE bands). Cluster analysis (WPGMA) of DGGE bands showed that bands from Salar de Huasco and Salar de Ascotán grouped together and samples from Salar de Atacama formed separate clusters in water and sediment samples, reflecting different Bacteroidetes communities between sites. Most of the sequences analyzed belonged to the family Flavobacteriaceae and clustered with the genera Psychroflexus, Gillisia, Maribacter, Muricauda, Flavobacterium, and Salegentibacter. The most abundant phylotype was highly related to Psychroflexus spp. and was recovered from all three study sites. The similarity of the analyzed sequences with their closest relatives in GenBank was typically Culture efforts will be necessary to get a better description of the diversity of this group in saline evaporitic basins of northern Chile.

  2. Biogeography of planktonic and coral-associated microorganisms across the Hawaiian Archipelago.

    Science.gov (United States)

    Salerno, Jennifer L; Bowen, Brian W; Rappé, Michael S

    2016-08-01

    Factors driving the distribution of marine microorganisms are widely debated and poorly understood. Recent studies show that free-living marine microbes exhibit geographical patterns indicative of limited dispersal. In contrast, host-associated microbes face a different set of dispersal challenges, and hosts may function as habitat 'islands' for resident microbial populations. Here, we examine the biogeographical distributions of planktonic and adjacent coral-associated bacterial communities across the Hawaiian Archipelago, Johnston Atoll (∼1400 km southwest of Hawaii) and American Samoa in the Pacific Ocean and investigate the potential underlying processes driving observed patterns. Statistical analyses of bacterial community structure, determined using a small-subunit ribosomal RNA gene-based approach, showed that bacterioplankton and coral-associated bacterial communities were distinct, and correlated with geographical distance between sites. In addition, biogeographical patterns of bacterial associates paralleled those of their host coral Porites lobata, highlighting the specificity of these associations and the impact that host dispersal may have on bacterial biogeography. Planktonic and coral-associated bacterial communities from distant Johnston Atoll were shown to be connected with communities from the center of the Hawaiian Archipelago, a pattern previously observed in fish and invertebrates. No significant correlations were detected with habitat type, temperature or depth. However, non-distance-based geographical groupings were detected, indicating that, in addition to dispersal, unidentified environmental factors also affected the distributions of bacterial communities investigated here. PMID:27222221

  3. Indicators of early successional trends in environmental condition and community function in constructed wetlands of the Athabasca Oilsands region

    Energy Technology Data Exchange (ETDEWEB)

    Ciborowski, J.; Kovalenko, K. [Windsor Univ., ON (Canada); Dixon, G.; Farwell, A. [Waterloo Univ., ON (Canada); Foote, L.; Mollard, F.; Roy, M. [Alberta Univ., Edmonton, AB (Canada); Smits, J.; Turcotte, D. [Saskatchewan Univ., Saskatoon, SK (Canada)

    2010-07-01

    This presentation reported on a study that compared interannual environmental variation in post-mining Athabasca oil sands landscapes. In particular, it compared biological, ecotoxicological and carbon dynamic aspects of sixteen 5 to 30 year old wetlands with different ages, reclamation materials and stockpiled surface materials such as peat. In addition to determining carbon fluxes, standing stocks of hydrocarbons were measured along with organic substrate, bacterioplankton, phytoplankton, biofilm, macrophytes, litter, zoobenthos, and aquatic insect emergence. Gas fluxes, microbial, plant, zoobenthic, amphibian, and tree swallow nestling production, and stable isotope signatures were used to determine carbon pathways, fluxes and budgets. Coarse taxon richness in reference wetlands reached an asymptote in 5 to 7 years. Richness, composition and emergent plant cover of oilsands-affected wetlands converged over a 15 to 20 year period with reference wetland patterns. The development of emergent but not submergent plant cover and associated biota accelerated with the addition of peat. Water chemistry was found to be more important than sediment in terms of regulating submergent biological properties. The study showed that the most important regulator of community composition may be residual salinity. Compared to more temperate biomes, the successional trends were slower.

  4. Selection Maintains Low Genomic GC Content in Marine SAR11 Lineages.

    Science.gov (United States)

    Luo, Haiwei; Thompson, Luke R; Stingl, Ulrich; Hughes, Austin L

    2015-10-01

    The genomic G+C content of ocean bacteria varies from below 30% to over 60%. This broad range of base composition is likely shaped by distinct mutational processes, recombination, effective population size, and selection driven by environmental factors. A number of studies have hypothesized that depletion of G/C in genomes of marine bacterioplankton cells is an adaptation to the nitrogen-poor pelagic oceans, but they failed to disentangle environmental factors from mutational biases and population history. Here, we reconstructed the evolutionary changes of bases at synonymous sites in genomes of two marine SAR11 populations and a freshwater counterpart with its evolutionary origin rooted in the marine lineage. Although they all have similar genome sizes, DNA repair gene repertoire, and base compositions, there is a stronger bias toward A/T changes, a reduced frequency of nitrogenous amino acids, and an exclusive occurrence of polyamine, opine, and taurine transport systems in the ocean populations, consistent with a greater nitrogen stress in surface oceans compared with freshwater lakes. Furthermore, the ratio of nonsynoymous to synonymous nucleotide diversity is not statistically distinguishable among these populations, suggesting that population history has a limited effect. Taken together, the ecological transition of SAR11 from ocean to freshwater habitats makes nitrogen more available to these organisms, and thus relaxation of purifying selection drove a genome-wide reduction in the frequency of G/C to A/T changes in the freshwater population. PMID:26116859

  5. Picoplankton seasonal variation and community structure in the northeast Adriatic coastal zone.

    Science.gov (United States)

    Silović, Tina; Balagué, Vanessa; Orlić, Sandi; Pedrós-Alió, Carlos

    2012-12-01

    The bacterial community in coastal waters of northeastern Adriatic Sea was dominated by SAR11 and Sulfitobacter taxa throughout the year. The seasonal distribution of bacterioplankton taxa showed continual differences between surface (0 m) and bottom (27 m) layers. The surface assemblage was represented by Actinobacteria, Cyanobacteria, Alphaproteobacteria, and Gammaproteobacteria, while the bottom assemblage was made up of Bacteroidetes, Cyanobacteria and Alphaproteobacteria. As SAR11 was more dominant in the bottom layer, its appearance may be linked to northward transport of oligotrophic waters of higher salinity from the south. Gammaproteobacteria appeared only in the surface layer during summer, influenced by higher amounts of nutrients, brought in by the Po River. Synechococcus was the most abundant taxon at the genus level. Dominance of Synechococcus during the whole season agrees with its dominance in terms of abundance determined by flow cytometry, and confirms its utmost importance in the picoplankton community of this area. We found two different types of Synechococcus: one type with high similarity to Synechococcus CC9902, present in the surface and bottom layers, and another one similar to Synechococcus WH7803, present only in the surface layer. Oligotrophic conditions together with complex hydrological features of this area were reflected in diversification and dynamic shifts of surface and bottom assemblages. PMID:22748097

  6. Metabolic and phylogenetic profile of bacterial community in Guishan coastal water (Pearl River Estuary), South China Sea

    Science.gov (United States)

    Hu, Xiaojuan; Liu, Qing; Li, Zhuojia; He, Zhili; Gong, Yingxue; Cao, Yucheng; Yang, Yufeng

    2014-10-01

    Characteristics of a microbial community are important as they indicate the status of aquatic ecosystems. In the present study, the metabolic and phylogenetic profile of the bacterioplankton community in Guishan coastal water (Pearl River Estuary), South China Sea, at 12 sites (S1-S12) were explored by community-level physiological profiling (CLPP) with BIOLOG Eco-plate and denaturing gradient gel electrophoresis (DGGE). Our results showed that the core mariculture area (S6, S7 and S8) and the sites associating with human activity and sewage discharge (S11 and S12) had higher microbial metabolic capability and bacterial community diversity than others (S1-5, S9-10). Especially, the diversity index of S11 and S12 calculated from both CLPP and DGGE data ( H>3.2) was higher than that of others as sewage discharge may increase water nitrogen and phosphorus nutrient. The bacterial community structure of S6, S8, S11 and S12 was greatly influenced by total phosphorous, salinity and total nitrogen. Based on DGGE fingerprinting, proteobacteria, especially γ- and α-proteobacteria, were found dominant at all sites. In conclusion, the aquaculture area and wharf had high microbial metabolic capability. The structure and composition of bacterial community were closely related to the level of phosphorus, salinity and nitrogen.

  7. Plant-associated bacterial populations on native and invasive plant species: comparisons between 2 freshwater environments.

    Science.gov (United States)

    Olapade, Ola A; Pung, Kayleigh

    2012-06-01

    Plant-microbial interactions have been well studied because of the ecological importance of such relationships in aquatic systems. However, general knowledge regarding the composition of these biofilm communities is still evolving, partly as a result of several confounding factors that are attributable to plant host properties and to hydrodynamic conditions in aquatic environments. In this study, the occurrences of various bacterial phylogenetic taxa on 2 native plants, i.e., mayapple (Podophyllum peltatum L.) and cow parsnip (Heracleum maximum Bartram), and on an invasive species, i.e., garlic mustard (Alliaria petiolata (M. Bieb.) Cavara & Grande), were quantitatively examined using nucleic acid staining and fluorescence in situ hybridization. The plants were incubated in triplicates for about a week within the Kalamazoo River and Pierce Cedar Creek as well as in microcosms. The bacterial groups targeted for enumeration are known to globally occur in relatively high abundance and are also ubiquitously distributed in freshwater environments. Fluorescence in situ hybridization analyses of the bacterioplankton assemblages revealed that the majority of bacterial cells that hybridized with the different probes were similar between the 2 sites. In contrast, the plant-associated populations while similar on the 3 plants incubated in Kalamazoo River, their representations were highest on the 2 native plants relative to the invasive species in Pierce Cedar Creek. Overall, our results further suggested that epiphytic bacterial assemblages are probably under the influences of and probably subsequently respond to multiple variables and conditions in aquatic milieus. PMID:22625420

  8. Differential Dissolved Organic Nitrogen Availability and Bacterial Aminopeptidase Activity in Limnic and Marine Waters.

    Science.gov (United States)

    Stepanauskas; Edling; Tranvik

    1999-10-01

    Abstract Nitrogen often limits primary production in marine ecosystems and its loading from terrestrial sources is the major cause of enhanced coastal eutrophication worldwide. About 70% of nitrogen transported by rivers globally is dissolved organic nitrogen (DON). Therefore, terrestrial DON is potentially an important component of the N dynamics in aquatic ecosystems, but the bioavailability of this organic nitrogen is poorly known. Bacterial extracellular hydrolysis of polymers is a bottleneck in the utilization of natural dissolved organic matter, mostly consisting of high molecular weight compounds. To study the bacterial utilization and extracellular enzymatic hydrolysis of DON, we developed a bioassay employing natural DON as the only N source, and N as the limiting nutrient. Bacterial cell density and activity of an unspecific aminopeptidase (AMPase) were followed in the cultures. Natural DON stimulated the cell-specific AMPase activity. Furthermore, refractory and humus-rich DOM caused a stronger stimulation than labile DOM. We propose that the previously reported inhibitory effect of humic substances on enzyme activity was outweighed by the induction of enzyme synthesis caused by refractory substrates. AMPase activity and the estimated DON bioavailability were more than twofold higher in seawater than in freshwater with identical substrate additions. This indicates that hydrolysis and turnover of land-derived DON is enhanced when it enters coastal marine waters, enabling it to support elevated bacterioplankton and phytoplankton growth.http://link.springer-ny.com/link/service/journals/00248/bibs/38n3p264.html

  9. Impact of freshwater inflow on bacterial abundance and activity in the estuarine system Ria de Aveiro

    Science.gov (United States)

    Santos, Luísa; Vaz, Leandro; Marcial Gomes, Newton C.; Vaz, Nuno; Dias, João Miguel; Cunha, Ângela; Almeida, Adelaide

    2014-02-01

    The influence of freshwater flow on bacterial communities in the estuarine system Ria de Aveiro (Portugal) was investigated at two sites differently impacted by river inputs, representative of the marine and brackish water zones of the estuary. Sampling events were clustered based on hydrological features. The hydrodynamic was simulated with a Lagrangian model and related to microbiological parameters. Estuarine bacteria responded to different freshwater regimes developing distinct patterns of abundance and activity at the marine and brackish water zones. A circulation pattern induced by high river inflow produced vertical stratification in the marine zone, promoting a seaward flux of bacterioplankton, and stimulating the import of riverine phytoplankton and particle-attached bacteria to the brackish water zone. Advective transport and resuspension processes contributed to a 3-times increase in abundance of particle-attached bacteria during intense freshwater inputs. Additionally, bacterial activity in the estuary was controlled by inorganic nitrogen, responding to different freshwater inputs, which, in association with different prevailing sources of organic substrates induced significant changes in bacterial production. The dynamic and main controlling factors of bacterial communities are clearly impacted by freshwater inputs. Therefore, significant changes in the recycling of nutrients by microbial activities can be expected from alterations in freshwater inputs either related to global climate change or regional hydrological regimes.

  10. Size distribution of autotrophy and microheterotrophy in reservoirs: implications for foodweb structure

    Energy Technology Data Exchange (ETDEWEB)

    Kimmel, B.L.

    1981-01-01

    Particle size is a primary determinant of resources available to consumers and of the efficiency of energy transfer through planktonic food chains. Dual radioisotopic labeling (with /sup 14/C-bicarbonate and /sup 3/H-acetate) and size fractionation of naturally-occurring phytoplankton-bacterioplankton assemblages were employed to examine the particle size distributions of planktonic autotrophy and microheterotrophy in four limnologically-dissimilar US reservoirs (Lake Mead, Arizona-Nevada, oligo-mesotrophic; Broken Bow Lake, Oklahoma, mesotrophic; Lake Texoma, Oklahoma-Texas, eutrophic; and Normandy Lake, Tennessee, eutrophic). Small nano- and ultraphytoplankton (< 8.0 ..mu..m) and free-living bacteria (< 3.0 ..mu..m) were primarly responsible for planktonic autotrophy and microheterotrophy, respecitvely, even in eutrophic conditions. Zooplankton grazing experiments indicated that (1) most grazing pressure occurs on 3.0 to 8.0 ..mu..m particles, (2) grazer limitation of the occurrence of attached bacteria amd microbial-detrital aggregates is unlikely, and (3) free-living bacteria are inefficiently harvested, relative to algae, by most reservoir zooplankton. Relative to autorophy, the microheterotrophic conversion of allochthonous dissolved organic matter and algal excretion products to bacterial biomass appears unlikely to be a significant source of organic carbon for planktonic grazers in most reservoirs.

  11. Impact of the inflow of Vistula river waters on the pelagic zone in the Gulf of Gdańsk

    Directory of Open Access Journals (Sweden)

    Nadezhda Torgunova

    2013-11-01

    Full Text Available The biomass, production, composition of autotrophic phytoplankton andhetero-trophic bacteria were studied along with environmental and biologicalparameters. Samples were taken from Vistula river water (at Kiezmark andfrom the river plume to the outer stations in the Gulf of Gdańsk (Baltic Sea in June2005. The phytoplankton biomass gradient appeared to be simply the result ofdilution of the river water in the sea water, whereas the bacterial abundanceand biomass dropped between the river station and the first sea water stations,a decrease that cannot be explained by the dilution effect. The Vistula waterstimulated the production mainly of bacterioplankton but also of phytoplanktonin the river plume as compared to rates measured in Vistula waters and at the opensea stations. However, this stimulation did not result in a measurable increasein biomasses, probably because of the short retention time of water in theriver plume. Phytoplankton production was correlated with phytoplankton biomass(Chl a, while bacterial production was correlated with phytoplanktonproduction and phytoplankton biomass (Chl a.

  12. Influence of zinc on bacterial populations and their proteolytic enzyme activities in freshwater environments: a cross-site comparison.

    Science.gov (United States)

    Rasmussen, Lauren; Olapade, Ola A

    2016-04-01

    Temporal responses of indigenous bacterial populations and proteolytic enzyme (i.e., aminopeptidase) activities in the bacterioplankton assemblages from 3 separate freshwater environments were examined after exposure to various zinc (Zn) concentrations under controlled microcosm conditions. Zn concentrations (ranging from 0 to 10 μmol/L) were added to water samples collected from the Kalamazoo River, Rice Creek, and Huron River and examined for bacterial abundance and aminopeptidase activities at various time intervals over a 48 h incubation period in the dark. The results showed that the Zn concentrations did not significantly influence total bacterial counts directly; however, aminopeptidase activities varied significantly to increasing zinc treatments over time. Also, analysis of variance and linear regression analyses revealed significant positive relationships between bacterial numbers and their hydrolytic enzyme activities, suggesting that both probably co-vary with increasing Zn concentrations in aquatic systems. The results from this study serve as additional evidence of the ecological role of Zn as an extracellular peptidase cofactor on the dynamics of bacterial assemblages in aquatic environments. PMID:26877164

  13. A between-river comparison of extracellular-enzyme activity.

    Science.gov (United States)

    Chappell, K R; Goulder, R

    1995-01-01

    River-water extracellular-enzyme activity in the lowland Rivers Ouse and Derwent, northeast England, had much in common. In both rivers, the mean enzyme activities over 15 months differed in the following order: leucine aminopeptidase > phosphatase > β-D-glucosidase > β-D-galactosi-idase and β-D-xylosidase. None of the five enzymes assayed had significant between-river difference in activity, and there was significant between-river correlation of β-D-glucosidase, phosphatase, and leucine-aminopeptidase activity. The common enzyme regimes were probably more due to between-river similarity of planktonic microbiota than to similar physico-chemical conditions. The potential for glucose uptake by bacterioplankton closely followed β-D-glucosidase activity in magnitude and periodicity. The potential for leucine uptake, however, was much less than leucine-aminopeptidase activity; hence rate of leucine release probably did not limit leucine uptake. There was an appreciable and highly variable proportion of free (river water; ranges were β-D-glucosidase 10-30%, phosphatase 53% to apparently 104%, and leucine aminopeptidase 22-98%. These free enzymes did not necessarily originate from planktonic microbiota and may explain the fairly loose coupling between whole-water enzyme activity and microbial variables. Marked downstream increase in enzyme activity, along about 104 km of the River Derwent, was found on only one of three sampling days; hence the single site used for regular sampling was reasonably representative of most of the river. PMID:24186635

  14. Recognition of individual genes in diverse microorganisms by cycling primed in situ amplification.

    Science.gov (United States)

    Kenzaka, Takehiko; Tamaki, Shigeru; Yamaguchi, Nobuyasu; Tani, Katsuji; Nasu, Masao

    2005-11-01

    Cycling primed in situ amplification-fluorescent in situ hybridization (CPRINS-FISH) was developed to recognize individual genes in a single bacterial cell. In CPRINS, the amplicon was long single-stranded DNA and thus retained within the permeabilized microbial cells. FISH with a multiply labeled fluorescent probe set enabled significant reduction in nonspecific background while maintaining high fluorescence signals of target bacteria. The ampicillin resistance gene in Escherichia coli, chloramphenicol acetyltransferase gene in different gram-negative strains, and RNA polymerase sigma factor (rpoD) gene in Aeromonas spp. could be detected under identical permeabilization conditions. After concentration of environmental freshwater samples onto polycarbonate filters and subsequent coating of filters in gelatin, no decrease in bacterial cell numbers was observed with extensive permeabilization. The detection rates of bacterioplankton in river and pond water samples by CPRINS-FISH with a universal 16S rRNA gene primer and probe set ranged from 65 to 76% of total cell counts (mean, 71%). The concentrations of cells detected by CPRINS-FISH targeting of the rpoD genes of Aeromonas sobria and A. hydrophila in the water samples varied between 2.1 x 10(3) and 9.0 x 10(3) cells ml(-1) and between undetectable and 5.1 x 10(2) cells ml(-1), respectively. These results demonstrate that CPRINS-FISH provides a high sensitivity for microscopic detection of bacteria carrying a specific gene in natural aquatic samples. PMID:16269764

  15. Inhibition of bacterial and phytoplanktonic metabolic activity in the lower River Rhine by ditallowdimethylammonium chloride.

    Science.gov (United States)

    Tubbing, D M; Admiraal, W

    1991-12-01

    The effects of a quaternary ammonium compound, ditallowdimethylammonium chloride (DTDMAC), on natural populations of bacteria and phytoplankton from the lower River Rhine were examined to estimate their sensitivity to the discharges of cationic surfactants in the river basin. In short-term experiments, significant decreases in the growth rate of bacterioplankton and in the photosynthetic rate of phytoplankton were observed at a nominal concentration of 0.03 to 0.1 mg of DTDMAC liter-1. Nitrification was measured with an ion-selective electrode and by the rate of acid production in ammonium-spiked river water and was found to be only sensitive to the addition of concentrations higher than 1 mg of DTDMAC liter-1. This does not support an earlier suggestion that ammonium-oxidizing bacteria are specifically sensitive to quaternary ammonium compounds. The effect of DTDMAC on thymidine incorporation was shown to depend strongly on the concentration of suspended material, which varied with the sampling date. This effect was also quantified in experimental manipulations with Rhine water. Calculations on the partitioning of DTDMAC between water and suspended matter confirmed the role of suspended solids and showed that an increase of the dissolved DTDMAC concentration in Rhine water by circa 0.01 mg liter-1 leads to a slight inhibition of the growth of heterotrophic bacteria. It is concluded that a total concentration of circa 0.01 mg of DTDMAC liter-1 measured in the River Rhine is likely to have biological consequences. PMID:1785934

  16. Seasonal baseline of nutrients and stable isotopes in a saline lake of Argentina: biogeochemical processes and river runoff effects.

    Science.gov (United States)

    Kopprio, Germán A; Kattner, Gerhard; Freije, R Hugo; de Paggi, Susana José; Lara, Rubén J

    2014-05-01

    The seasonal variability of inorganic and organic nutrients and stable isotopes and their relations with plankton and environmental conditions were monitored in Lake Chasicó. Principal component analysis evidenced the strong influence of the river runoff on several biogeochemical variables. Silicate concentrations were controlled by diatom biomass and river discharge. Higher values of nitrate and soluble reactive phosphorus (SRP) indicated agricultural uses in the river basin. Elevated pH values (∼ 9) inhibiting nitrification in the lake explained partially the dominance of ammonium: ∼ 83 % of dissolved inorganic nitrogen (DIN). The low DIN/SRP ratio inferred nitrogen limitation, although the hypotheses of iron and CO2 limitation are relevant in alkaline lakes. Particulate organic matter (POM) and dissolved organic matter (DOM) were mainly of autochthonous origin. The main allochthonous input was imported by the river as POM owning to the arid conditions. Dissolved organic carbon was likely top-down regulated by the bacterioplankton grazer Brachionus plicatilis. The δ(13)C signature was a good indicator of primary production and its values were influenced probably by CO2 limitation. The δ(15)N did not evidence nitrogen fixation and suggested the effects of anthropogenic activities. The preservation of a good water quality in the lake is crucial for resource management. PMID:24415133

  17. Ecological niche separation in the Polynucleobacter subclusters linked to quality of dissolved organic matter: a demonstration using a high sensitivity cultivation-based approach.

    Science.gov (United States)

    Watanabe, Keiji; Komatsu, Nobuyuki; Kitamura, Tatsumi; Ishii, Yuichi; Park, Ho-Dong; Miyata, Ryo; Noda, Naohiro; Sekiguchi, Yuji; Satou, Takayuki; Watanabe, Mirai; Yamamura, Shigeki; Imai, Akio; Hayashi, Seiji

    2012-09-01

    The free-living, cosmopolitan, freshwater betaproteobacterial bacterioplankton genus Polynucleobacter was detected in different years in 11 lakes of varying types and a river using the size-exclusion assay method (SEAM). Of the 350 strains isolated, 228 (65.1%) were affiliated with the Polynucleobacter subclusters PnecC (30.0%) and PnecD (35.1%). Significant positive correlations between fluorescence in situ hybridization and SEAM data were observed in the relative abundance of PnecC and PnecD bacteria to Polynucleobacter communities (PnecC + PnecD). Isolates were mainly PnecC bacteria in the samples with a high specific UV absorbance at 254 nm (SUVA(254) ), and a low total hydrolysable neutral carbohydrate and amino acid (THneutralCH + THAA) content of the dissolved organic matter (DOM) fraction, which is known to be correlated with a high humic content. In contrast, the PnecD bacteria were abundant in samples with high chlorophyll a and/or THneutralCH + THAA concentrations, indicative of primary productivity. With few exceptions, differences in the relative abundance of PnecC and PnecD in each sample, determined using a high-sensitivity cultivation-based approach, were due to DOM quality. These results suggest that the major DOM component in the field, which is allochthonously or autochthonously derived, is a key factor for ecological niche separation between PnecC and PnecD subclusters. PMID:22759205

  18. Dynamic of virioplankton abundance and its environmental control in the Charente estuary (France).

    Science.gov (United States)

    Auguet, J C; Montanié, H; Delmas, D; Hartmann, H J; Huet, V

    2005-10-01

    The Charente River provides nutrient- and virus-rich freshwater input to the Marennes Oléron Basin, the largest oyster-producing region in Europe. To evaluate virioplankton distribution in the Charente Estuary and identify which environmental variables control dynamic of virioplankton abundance, five stations defined by a salinity gradient (0-0.5, 0.6-5, 13-17, 20-24, and higher than 30 PSU) were surveyed over a year. Viral abundance was related to bacterioplankton abundance and activities, photosynthetic pigments, nutrient concentration, and physical parameters (temperature and salinity). On a spatial scale, virus displayed a decreasing pattern seaward with abundance ranging over the sampling period from 1.4x10(7) to 20.8x10(7) viruses mL-1 making virioplankton the most abundant component of planktonic microorganisms in the Charente Estuary. A good correlation was found between viral and bacterial abundance (rs=0.85). Furthermore, bacterial abundance was the most important predictor of viral abundance explaining alone between 66% (winter) and 76% (summer) of viral variability. However, no relation existed between viral abundance and chlorophyll a. Temporal variations in viral distributions were mainly controlled by temperature through the control of bacterial dynamics. Spatial variations of viral abundance were influenced by hydrodynamic conditions especially during the winter season where virioplankton distribution was entirely driven by mixing processes. PMID:16328658

  19. Co-occurrence patterns in aquatic bacterial communities across changing permafrost landscapes

    Directory of Open Access Journals (Sweden)

    J. Comte

    2015-07-01

    Full Text Available Permafrost thaw ponds and lakes are widespread across the northern landscape and may play a central role in global biogeochemical cycles, yet knowledge about their microbial ecology is limited. We sampled a set of thaw ponds and lakes as well as shallow rock-basin lakes that are located in distinct valleys along a North–South permafrost degradation gradient. We applied high-throughput sequencing of the 16S rRNA gene to determine co-occurrence patterns among bacterial taxa, and then analyzed these results relative to environmental variables to identify factors controlling bacterial community structure. Network analysis was applied to identify possible ecological linkages among the bacterial taxa and with abiotic and biotic variables. The results showed an overall high level of shared taxa among bacterial communities within each valley, however the bacterial co-occurrence patterns were non-random, with evidence of habitat preferences. There were taxonomic differences in bacterial assemblages among the different valleys that were statistically related to dissolved organic carbon concentration, conductivity and phytoplankton biomass. Co-occurrence networks revealed complex interdependencies within the bacterioplankton communities and showed contrasting linkages to environmental conditions among the main bacterial phyla. The thaw pond networks were composed of a limited number of highly connected taxa. This "small world network" property would render the communities more robust to environmental change but vulnerable to the loss of microbial keystone species.

  20. Mining microbial metatranscriptomes for expression of antibiotic resistance genes under natural conditions

    Science.gov (United States)

    Versluis, Dennis; D'Andrea, Marco Maria; Ramiro Garcia, Javier; Leimena, Milkha M.; Hugenholtz, Floor; Zhang, Jing; Öztürk, Başak; Nylund, Lotta; Sipkema, Detmer; Schaik, Willem Van; de Vos, Willem M.; Kleerebezem, Michiel; Smidt, Hauke; Passel, Mark W. J. Van

    2015-07-01

    Antibiotic resistance genes are found in a broad range of ecological niches associated with complex microbiota. Here we investigated if resistance genes are not only present, but also transcribed under natural conditions. Furthermore, we examined the potential for antibiotic production by assessing the expression of associated secondary metabolite biosynthesis gene clusters. Metatranscriptome datasets from intestinal microbiota of four human adults, one human infant, 15 mice and six pigs, of which only the latter have received antibiotics prior to the study, as well as from sea bacterioplankton, a marine sponge, forest soil and sub-seafloor sediment, were investigated. We found that resistance genes are expressed in all studied ecological niches, albeit with niche-specific differences in relative expression levels and diversity of transcripts. For example, in mice and human infant microbiota predominantly tetracycline resistance genes were expressed while in human adult microbiota the spectrum of expressed genes was more diverse, and also included β-lactam, aminoglycoside and macrolide resistance genes. Resistance gene expression could result from the presence of natural antibiotics in the environment, although we could not link it to expression of corresponding secondary metabolites biosynthesis clusters. Alternatively, resistance gene expression could be constitutive, or these genes serve alternative roles besides antibiotic resistance.

  1. Invasive lionfish harbor a different external bacterial community than native Bahamian fishes

    Science.gov (United States)

    Stevens, J. L.; Olson, J. B.

    2013-12-01

    The introduction and subsequent spread of lionfish into the Atlantic Ocean and Caribbean Sea has become a worldwide conservation issue. These highly successful invaders may also be capable of introducing non-native microorganisms to the invaded regions. This study compared the bacterial communities associated with lionfish external tissue to those of native Bahamian fishes and ambient water. Terminal restriction fragment length polymorphism analyses demonstrated that lionfish bacterial communities were significantly different than those associated with three native Bahamian fishes. Additionally, all fishes harbored distinct bacterial communities from the ambient bacterioplankton. Analysis of bacterial clone libraries from invasive lionfish and native squirrelfish indicated that lionfish communities were more diverse than those associated with squirrelfish, yet did not contain known fish pathogens. Using microscopy and molecular genetic approaches, lionfish eggs were examined for the presence of bacteria to evaluate the capacity for vertical transmission. Eggs removed from the ovaries of gravid females were free of bacteria, suggesting that lionfish likely acquire bacteria from the environment. This study was the first examination of bacterial communities associated with the invasive lionfish and indicated that they support different communities of environmentally derived bacteria than Caribbean reef fishes.

  2. Analysis of Lagoonal Ecosystems in the Po River Delta Associated with Intensive Aquaculture

    Science.gov (United States)

    Sorokin, Yu. I.; Sorokin, P. Yu.; Ravagnan, G.

    1999-03-01

    Observations on structure and functioning of coastal lagoon ecosystems experiencing a high level of eutrophication impact were accomplished in three lagoons of Ca'Pisani integrated within an experimental aquaculture enterprise variously fertilized by waste effluents discharged from and intensive fish culture plant. During August and early September an extremely dense bloom of dinoflagellate Alexandrium tamarensewas recorded in these lagoons with the density of phytoplankton up to 190 g m -3of wet biomass, and primary production 2 to 6 mg Cl -1 day -1. The diel dissolved oxygen fluctuations in water column during the bloom reached 15-20 mg O 2 l -1. The wet biomass of bacterioplankton in the lagoons attained 5-9 g m -3. The microzooplankton was dominated by ciliates with biomass 1 to 19 g m -3. The daytime mesozooplankton was dominated by calanoid copepods with a biomass 0·05-0·25 g m -3, while the biomass of the demersal zooplankton at night attained 2 to 14 g m -3. In the lagoon of Ocaro, the phototrophic plankton was dominated by the symbiotic ciliate Mesodinium.The labile sulphides content in the upper layer of the bottom attained over 1 g S dm -3of wet silt. The rate of microbial sulphate reduction was 5-10 mg S dm -3day -1. The data are generalized within the energy balance in these specific anthropogenically transformed pelagic communities.

  3. Differential utilization patterns of dissolved organic phosphorus compounds by heterotrophic bacteria in two mountain lakes.

    Science.gov (United States)

    Rofner, Carina; Sommaruga, Ruben; Pérez, María Teresa

    2016-09-01

    Although phosphorus limitation is common in freshwaters and bacteria are known to use dissolved organic phosphorus (DOP), little is known about how efficiently DOP compounds are taken up by individual bacterial taxa. Here, we assessed bacterial uptake of three model DOP substrates in two mountain lakes and examined whether DOP uptake followed concentration-dependent patterns. We determined bulk uptake rates by the bacterioplankton and examined bacterial taxon-specific substrate uptake patterns using microautoradiography combined with catalyzed reporter deposition-fluorescence in situ hybridization. Our results show that in the oligotrophic alpine lake, bacteria took up ATP, glucose-6-phosphate and glycerol-3-phosphate to similar extents (mean 29.7 ± 4.3% Bacteria), whereas in the subalpine mesotrophic lake, ca. 40% of bacteria took up glucose-6-phosphate, but only ∼20% took up ATP or glycerol-3-phosphate. In both lakes, the R-BT cluster of Betaproteobacteria (lineage of genus Limnohabitans) was over-represented in glucose-6-phosphate and glycerol-3-phosphate uptake, whereas AcI Actinobacteria were under-represented in the uptake of those substrates. Alphaproteobacteria and Bacteroidetes contributed to DOP uptake proportionally to their in situ abundance. Our results demonstrate that R-BT Betaproteobacteria are the most active bacteria in DOP acquisition, whereas the abundant AcI Actinobacteria may either lack high affinity DOP uptake systems or have reduced phosphorus requirements. PMID:27312963

  4. The influence of light and water mass on bacterial population dynamics in the Amundsen Sea Polynya

    Directory of Open Access Journals (Sweden)

    Inga Richert

    2015-04-01

    Full Text Available Abstract Despite being perpetually cold, seasonally ice-covered and dark, the coastal Southern Ocean is highly productive and harbors a diverse microbiota. During the austral summer, ice-free coastal patches (or polynyas form, exposing pelagic organisms to sunlight, triggering intense phytoplankton blooms. This strong seasonality is likely to influence bacterioplankton community composition (BCC. For the most part, we do not fully understand the environmental drivers controlling high-latitude BCC and the biogeochemical cycles they mediate. In this study, the Amundsen Sea Polynya was used as a model system to investigate important environmental factors that shape the coastal Southern Ocean microbiota. Population dynamics in terms of occurrence and activity of abundant taxa was studied in both environmental samples and microcosm experiments by using 454 pyrosequencing of 16S rRNA genes. We found that the BCC in the photic epipelagic zone had low richness, with dominant bacterial populations being related to taxa known to benefit from high organic carbon and nutrient loads (copiotrophs. In contrast, the BCC in deeper mesopelagic water masses had higher richness, featuring taxa known to benefit from low organic carbon and nutrient loads (oligotrophs. Incubation experiments indicated that direct impacts of light and competition for organic nutrients are two important factors shaping BCC in the Amundsen Sea Polynya.

  5. Quantifying the effect of environment stability on the transcription factor repertoire of marine microbes

    Directory of Open Access Journals (Sweden)

    Kostadinov Ivaylo

    2011-09-01

    Full Text Available Abstract Background DNA-binding transcription factors (TFs regulate cellular functions in prokaryotes, often in response to environmental stimuli. Thus, the environment exerts constant selective pressure on the TF gene content of microbial communities. Recently a study on marine Synechococcus strains detected differences in their genomic TF content related to environmental adaptation, but so far the effect of environmental parameters on the content of TFs in bacterial communities has not been systematically investigated. Results We quantified the effect of environment stability on the transcription factor repertoire of marine pelagic microbes from the Global Ocean Sampling (GOS metagenome using interpolated physico-chemical parameters and multivariate statistics. Thirty-five percent of the difference in relative TF abundances between samples could be explained by environment stability. Six percent was attributable to spatial distance but none to a combination of both spatial distance and stability. Some individual TFs showed a stronger relationship to environment stability and space than the total TF pool. Conclusions Environmental stability appears to have a clearly detectable effect on TF gene content in bacterioplanktonic communities described by the GOS metagenome. Interpolated environmental parameters were shown to compare well to in situ measurements and were essential for quantifying the effect of the environment on the TF content. It is demonstrated that comprehensive and well-structured contextual data will strongly enhance our ability to interpret the functional potential of microbes from metagenomic data.

  6. Picoplankton Community Composition by CARD-FISH and Flow Cytometric Techniques: A Preliminary Study in Central Adriatic Sea Water

    Directory of Open Access Journals (Sweden)

    Anita Manti

    2012-01-01

    Full Text Available Data concerning picoplanktonic community composition and abundance in the Central Adriatic Sea are presented in an effort to improve the knowledge of bacterioplankton and autotrophic picoplankton and their seasonal changes. Flow cytometry analyses revealed the presence of two distinct bacteria populations: HNA and LNA cells. HNA cells showed an explicit correlation with viable and actively respiring cells. The study of viability and activity may increase our knowledge of the part that contributes really to the remineralization and bacterial biomass production. Authotrophic picoplankton abundance, especially picocyanobacteria, was strongly influenced by seasonality, indicating that light availability and water temperature are very important regulating factors. In terms of total carbon biomass, the main contribution came from heterotrophic bacteria with a lower contribution from autotrophic picoplankton. CARD-FISH evidenced, within the Eubacteria domain, the dominance of members of the phyla Alphaproteobacteria, with a strong contribution from SAR11clade, followed by Cytophaga-Flavobacterium and Gammaproteobacteria. The bacterial groups detected contributed differently depending when the sample was taken, suggesting possible seasonal patterns. This study documents for the first time picoplankton community composition in the Central Adriatic Sea using two different approaches, FCM and CARD-FISH, and could provide preliminary data for future studies.

  7. Heterotrophic bacterial production: Relationships to biological and abiological factors in estuarine environments

    International Nuclear Information System (INIS)

    Ecotoxicological effects of creosote contamination on benthic bacterial communities in the Elizabeth River, Virginia were investigated using both structural an functional microbial parameters. Results indicated that cell specific and total heterotrophic bacterial production parameters were depressed in a dose-dependent manner with increasing sediment PAH concentrations. Toxicity effects upon production were modified by temporal trends associated with temperature as well as spatial sediment characteristics. Of the parameters employed, the tritiated thymidine production assay was found to be the most sensitive for detection of ecotoxicological effects. Bacterial abundance and production were examined during a destratification event in the lower James River, Virginia. Bacterial abundance, although significantly different between stations, did not change over the study. Bacterial production (3H-Tdr incorporation) in surface waters was significantly less during the mixed period 187 μg C·1-1· d-1 compared to the most stratified state (324μg C·1-1· d-1). Correlations between bacteria and chlorophyll were diminished during the mixed period. Total and flagellate specific grazing rates upon bacteria were reduced during the onset of destratification. Relationships between bacterial and nutrient parameters also indicated a strong influence of destratification. These results indicate that destratification changes trophic interactions within the microbial loop, which are not necessarily reflected in temporal patterns of bacterial abundance. Bacterioplankton production, and ammonium assimilation and remineralization were examined between April and August 1988 in the lower York River, Va

  8. Size distribution of autotrophy and microheterotrophy in reservoirs: implications for foodweb structure

    International Nuclear Information System (INIS)

    Particle size is a primary determinant of resources available to consumers and of the efficiency of energy transfer through planktonic food chains. Dual radioisotopic labeling (with 14C-bicarbonate and 3H-acetate) and size fractionation of naturally-occurring phytoplankton-bacterioplankton assemblages were employed to examine the particle size distributions of planktonic autotrophy and microheterotrophy in four limnologically-dissimilar US reservoirs (Lake Mead, Arizona-Nevada, oligo-mesotrophic; Broken Bow Lake, Oklahoma, mesotrophic; Lake Texoma, Oklahoma-Texas, eutrophic; and Normandy Lake, Tennessee, eutrophic). Small nano- and ultraphytoplankton (< 8.0 μm) and free-living bacteria (< 3.0 μm) were primarly responsible for planktonic autotrophy and microheterotrophy, respecitvely, even in eutrophic conditions. Zooplankton grazing experiments indicated that (1) most grazing pressure occurs on 3.0 to 8.0 μm particles, (2) grazer limitation of the occurrence of attached bacteria amd microbial-detrital aggregates is unlikely, and (3) free-living bacteria are inefficiently harvested, relative to algae, by most reservoir zooplankton. Relative to autorophy, the microheterotrophic conversion of allochthonous dissolved organic matter and algal excretion products to bacterial biomass appears unlikely to be a significant source of organic carbon for planktonic grazers in most reservoirs

  9. Controls on marine carbon fluxes via phytoplankton-microzooplankton interactions in continental shelf waters. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    1994-05-01

    The project is an in-depth evaluation of the phytoplankton-microzooplankton trophic link. The principal goals of the project remain as originally proposed: (1) Impact of grazing by phagotrophic microzooplankton on phytoplankton, particularly on phototrophic cells <5 {mu}m in size, which are not effectively grazed by macrozooplankton. (2) Impact of grazing by phagotrophic microzooplankton on bacterioplankton. (3) Taxon-specific growth rates of phytoplankton in situ, particularly of <5 {mu}m sized cells, as they are affected by phagotrophy rates. The authors are developing protocols for making quantitative estimates of grazing by phagotrophic protists on ultraphytoplankton, and for determining the intrinsic reproductive rates of phytoplankton species. They have also begun a series of experiments, testing and utilizing these methods, evaluating the grazing impact of flagellates and ciliates on phytoplankton species of different sizes and taxonomic affinities. A series of preliminary experiments in coastal waters adjacent to the Oregon Institute of Marine Biology have provided a coastal benchmark. They participated in a preliminary cruise in May, 1993 to the OMP field site off Cape Hatteras. Their purpose was to obtain background information on heterotrophic microbial distributional patterns in this region and to measure rates of protist bacterivory.

  10. Evidence for a temperature acclimation mechanism in bacteria: an empirical test of a membrane-mediated trade-off

    Science.gov (United States)

    Hall, Edward K.; Singer, Gabriel A.; Kainz, Martin J.; Lennon, Jay T.

    2010-01-01

    1. Shifts in bacterial community composition along temporal and spatial temperature gradients occur in a wide range of habitats and have potentially important implications for ecosystem functioning. However, it is often challenging to empirically link an adaptation or acclimation that defines environmental niche or biogeography with a quantifiable phenotype, especially in micro-organisms. 2. Here we evaluate a possible mechanistic explanation for shifts in bacterioplankton community composition in response to temperature by testing a previously hypothesized membrane mediated trade-off between resource acquisition and respiratory costs. 3. We isolated two strains of Flavobacterium sp. at two temperatures (cold isolate and warm isolate) from the epilimnion of a small temperate lake in North Central Minnesota. 4. Compared with the cold isolate the warm isolate had higher growth rate, higher carrying capacity, lower lag time and lower respiration at the high temperature and lower phosphorus uptake at the low temperature. We also observed significant differences in membrane lipid composition between isolates and between environments that were consistent with adjustments necessary to maintain membrane fluidity at different temperatures. 5. Our results suggest that temperature acclimation in planktonic bacteria is, in part, a resource-dependent membrane-facilitated phenomenon. This study provides an explicit example of how a quantifiable phenotype can be linked through physiology to competitive ability and environmental niche.

  11. Influence of the Anthropogenic Load on Microplankton of a Mesotrophic Reservoir

    Science.gov (United States)

    Golovko, T. V.; Popova, A. F.; Michjliuk, T. I.; Jurishinec, V.; Kemp, R.

    2005-12-01

    .8 and 2.3-fold, respectively. Moreover, the coefficients of variation of structural indices were 1.5-2.0-fold higher at the Station 2 as a result of inconsistency of volume and timing of sewage introduction there. The production studies revealed that despite the lack of substantial differences in bacterial reproductive activity (K, days-1), the specific speed of energy flow through the bacterioplankton (A/B, days-1) was 1.5-fold higher at the Station 1 compare to the polluted Station 2. The distribution of heterotrophic flagellates and infusorians, among which the dominated species belonged to genera Tintinnidium and Strombidium, was similar to that of phyto- and bacterioplankton. The structural indices of microzooplankton were several times higher at the Station 2 (N=748x103 cells/dm3, B=87.7 mg/dm3, S=31.3x106 um2/dm3) compared to the Station 1 (N=30x103 cells/dm3, B=7.3 mg/dm3, S=3.2x106 um2/dm3).

  12. Ecosystem element transport model for Lake Eckarfjaerden

    Energy Technology Data Exchange (ETDEWEB)

    Konovalenko, L.; Bradshaw, C. [The Department of Ecology, Environment and Plant Sciences, Stockholm University (Sweden); Andersson, E.; Kautsky, U. [Swedish Nuclear Fuel and Waste Management Co. - SKB (Sweden)

    2014-07-01

    The ecosystem transport model of elements was developed for Lake Eckarfjaerden located in the Forsmark area in Sweden. Forsmark has currently a low level repository (SFR) and a repository for spent fuel is planned. A large number of data collected during site-investigation program 2002-2009 for planning the repository were available for the creation of the compartment model based on carbon circulation, physical and biological processes (e.g. primary production, consumption, respiration). The model is site-specific in the sense that the food web model is adapted to the actual food web at the site, and most estimates of biomass and metabolic rates for the organisms and meteorological data originate from site data. The functional organism groups of Lake Eckarfjaerden were considered as separate compartments: bacterio-plankton, benthic bacteria, macro-algae, phytoplankton, zooplankton, fish, benthic fauna. Two functional groups of bacteria were taken into account for the reason that they have the highest biomass of all functional groups during the winter, comprising 36% of the total biomass. Effects of ecological parameters, such as bacteria and algae biomass, on redistribution of a hypothetical radionuclide release in the lake were examined. The ecosystem model was used to estimate the environmental transfer of several elements (U, Th, Ra) and their isotopes (U-238, U-234,Th-232, Ra-226) to various aquatic organisms in the lake, using element-specific distribution coefficients for suspended particle and sediment. Results of chemical analyses of the water, sediment and biota were used for model validation. The model gives estimates of concentration factors for fish based on modelling rather on in situ measurement, which reduces the uncertainties for many radionuclides with scarce of data. Document available in abstract form only. (authors)

  13. Novelty and spatio-temporal heterogeneity in the bacterial diversity of hypersaline Lake Tebenquiche (Salar de Atacama).

    Science.gov (United States)

    Demergasso, Cecilia; Escudero, Lorena; Casamayor, Emilio O; Chong, Guillermo; Balagué, Vanessa; Pedrós-Alió, Carlos

    2008-07-01

    Lake Tebenquiche is one of the largest saline water bodies in the Salar de Atacama at 2,500 m above sea level in northeastern Chile. Bacteria inhabiting there have to deal with extreme changes in salinity, temperature and UV dose (i.e., high environmental dissimilarity in the physical landscape). We analyzed the bacterioplankton structure of this lake by 16S rRNA gene analyses along a spatio-temporal survey. The bacterial assemblage within the lake was quite heterogeneous both in space and time. Salinity changed both in space and time ranging between 1 and 30% (w/v), and total abundances of planktonic prokaryotes in the different sampling points within the lake ranged between two and nine times 10(6) cells mL(-1). Community composition changed accordingly to the particular salinity of each point as depicted by genetic fingerprinting analyses (denaturing gradient gel electrophoresis), showing a high level of variation in species composition from place to place (beta-diversity). Three selected sites were analyzed in more detail by clone libraries. We observed a predominance of Bacteroidetes (about one third of the clones) and Gammaproteobacteria (another third) with respect to all the other bacterial groups. The diversity of Bacteroidetes sequences was large and showed a remarkable degree of novelty. Bacteroidetes formed at least four clusters with no cultured relatives in databases and rather distantly related to any known 16S rRNA sequence. Within this phylum, a rich and diverse presence of Salinibacter relatives was found in the saltiest part of the lake. Lake Tebenquiche included several novel microorganisms of environmental importance and appeared as a large unexplored reservoir of unknown bacteria. PMID:18347752

  14. The Black Queen Hypothesis: evolution of dependencies through adaptive gene loss.

    Science.gov (United States)

    Morris, J Jeffrey; Lenski, Richard E; Zinser, Erik R

    2012-01-01

    Reductive genomic evolution, driven by genetic drift, is common in endosymbiotic bacteria. Genome reduction is less common in free-living organisms, but it has occurred in the numerically dominant open-ocean bacterioplankton Prochlorococcus and "Candidatus Pelagibacter," and in these cases the reduction appears to be driven by natural selection rather than drift. Gene loss in free-living organisms may leave them dependent on cooccurring microbes for lost metabolic functions. We present the Black Queen Hypothesis (BQH), a novel theory of reductive evolution that explains how selection leads to such dependencies; its name refers to the queen of spades in the game Hearts, where the usual strategy is to avoid taking this card. Gene loss can provide a selective advantage by conserving an organism's limiting resources, provided the gene's function is dispensable. Many vital genetic functions are leaky, thereby unavoidably producing public goods that are available to the entire community. Such leaky functions are thus dispensable for individuals, provided they are not lost entirely from the community. The BQH predicts that the loss of a costly, leaky function is selectively favored at the individual level and will proceed until the production of public goods is just sufficient to support the equilibrium community; at that point, the benefit of any further loss would be offset by the cost. Evolution in accordance with the BQH thus generates "beneficiaries" of reduced genomic content that are dependent on leaky "helpers," and it may explain the observed nonuniversality of prototrophy, stress resistance, and other cellular functions in the microbial world. PMID:22448042

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

    Science.gov (United States)

    Van Wambeke, F.; Pfreundt, U.; Barani, A.; Berthelot, H.; Moutin, T.; Rodier, M.; Hess, W. R.; Bonnet, S.

    2015-12-01

    N2 fixation fuels ~ 50 % of new primary production in the oligotrophic South Pacific Ocean. The VAHINE mesocosm experiment designed to track the fate of diazotroph derived nitrogen (DDN) in the New Caledonia lagoon. Here, we examined the temporal dynamics of heterotrophic bacterial production during this experiment. Three replicate large-volume (~ 50 m3) mesocosms were deployed and were intentionally fertilized with dissolved inorganic phosphorus (DIP) to stimulate N2 fixation. We specifically examined relationships between N2 fixation rates and primary production, determined bacterial growth efficiency and established carbon budgets of the system from the DIP fertilization to the end of the experiment (days 5-23). Heterotrophic bacterioplankton production (BP) and alkaline phosphatase activity (APA) were statistically higher during the second phase of the experiment (P2: days 15-23), when chlorophyll biomass started to increase compared to the first phase (P1: days 5-14). Among autotrophs, Synechococcus abundances increased during P2, possibly related to its capacity to assimilate leucine and to produce alkaline phosphatase. Bacterial growth efficiency based on the carbon budget was notably higher than generally cited for oligotrophic environments (27-43 %), possibly due to a high representation of proteorhodopsin-containing organisms within the picoplanctonic community. The carbon budget showed that the main fate of gross primary production (particulate + dissolved) was respiration (67 %), and export through sedimentation (17 %). BP was highly correlated with particulate primary production and chlorophyll biomass during both phases of the experiment but slightly correlated, and only during P2 phase, with N2 fixation rates. Our results suggest that most of the DDN reached the heterotrophic bacterial community through indirect processes, like mortality, lysis and grazing.

  16. High molecular weight dissolved organic matter enrichment selects for methylotrophs in dilution to extinction cultures.

    Science.gov (United States)

    Sosa, Oscar A; Gifford, Scott M; Repeta, Daniel J; DeLong, Edward F

    2015-12-01

    The role of bacterioplankton in the cycling of marine dissolved organic matter (DOM) is central to the carbon and energy balance in the ocean, yet there are few model organisms available to investigate the genes, metabolic pathways, and biochemical mechanisms involved in the degradation of this globally important carbon pool. To obtain microbial isolates capable of degrading semi-labile DOM for growth, we conducted dilution to extinction cultivation experiments using seawater enriched with high molecular weight (HMW) DOM. In total, 93 isolates were obtained. Amendments using HMW DOM to increase the dissolved organic carbon concentration 4x (280 μM) or 10x (700 μM) the ocean surface water concentrations yielded positive growth in 4-6% of replicate dilutions, whereas amended controls. The majority (71%) of isolates displayed a distinct increase in cell yields when grown in increasing concentrations of HMW DOM. Whole-genome sequencing was used to screen the culture collection for purity and to determine the phylogenetic identity of the isolates. Eleven percent of the isolates belonged to the gammaproteobacteria including Alteromonadales (the SAR92 clade) and Vibrio. Surprisingly, 85% of isolates belonged to the methylotrophic OM43 clade of betaproteobacteria, bacteria thought to metabolically specialize in degrading C1 compounds. Growth of these isolates on methanol confirmed their methylotrophic phenotype. Our results indicate that dilution to extinction cultivation enriched with natural sources of organic substrates has a potential to reveal the previously unsuspected relationships between naturally occurring organic nutrients and the microorganisms that consume them. PMID:25978545

  17. Food web structure in oil sands reclaimed wetlands.

    Science.gov (United States)

    Kovalenko, K E; Ciborowski, J J H; Daly, C; Dixon, D G; Farwell, A J; Foote, A L; Frederick, K R; Costa, J M Gardner; Kennedy, K; Liber, K; Roy, M C; Slama, C A; Smits, J E G

    2013-07-01

    Boreal wetlands play an important role in global carbon balance. However, their ecosystem function is threatened by direct anthropogenic disturbance and climate change. Oil sands surface mining in the boreal regions of Western Canada denudes tracts of land of organic materials, leaves large areas in need of reclamation, and generates considerable quantities of extraction process-affected materials. Knowledge and validation of reclamation techniques that lead to self-sustaining wetlands has lagged behind development of protocols for reclaiming terrestrial systems. It is important to know whether wetlands reclaimed with oil sands process materials can be restored to levels equivalent to their original ecosystem function. We approached this question by assessing carbon flows and food web structure in naturally formed and oil sands-affected wetlands constructed in 1970-2004 in the postmining landscape. We evaluated whether a prescribed reclamation strategy, involving organic matter amendment, accelerated reclaimed wetland development, leading to wetlands that were more similar to their natural marsh counterparts than wetlands that were not supplemented with organic matter. We measured compartment standing stocks for bacterioplankton, microbial biofilm, macrophytes, detritus, and zoobenthos; concentrations of dissolved organic carbon and residual naphthenic acids; and microbial production, gas fluxes, and aquatic-terrestrial exports (i.e., aquatic insect emergence). The total biomass of several biotic compartments differed significantly between oil sands and reference wetlands. Submerged macrophyte biomass, macroinvertebrate trophic diversity, and predator biomass and richness were lower in oil sands-affected wetlands than in reference wetlands. There was insufficient evidence to conclude that wetland age and wetland amendment with peat-mineral mix mitigate effects of oil sands waste materials on the fully aquatic biota. Although high variability was observed within

  18. Small Boreal Lake Ecosystem Evolution under the Influence of Natural and Anthropogenic Factors: Results of Multidisciplinary Long-Term Study

    Directory of Open Access Journals (Sweden)

    Liudmila Shirokova

    2016-07-01

    Full Text Available Small aquatic ecosystems of the boreal zone are known to be most sensitive indicators of on-going environmental change as well as local anthropogenic pressure, while being highly vulnerable to external impacts. Compared to rather detailed knowledge of the evolution of large and small lakes in Scandinavia and Canada, and large lakes in Eurasia, highly abundant small boreal lakes of northwest Russia have received very little attention, although they may become important centers of attraction of growing rural population in the near future. Here we present the results of a multidisciplinary, multi-annual study of a small boreal humic lake of NW Russia. A shallow (3 m and a deep (16 m site of this lake were regularly sampled for a range of chemical and biological parameters. Average multi-daily, summer-time values of the epilimnion (upper oxygenated layer of the lake provided indications of possible trends in temperature, nutrients, and bacterio-plankton concentration that revealed the local pollution impact in the shallow zone and overall environmental trend in the deep sampling point of the lake. Organic phosphorus, nitrate, and lead were found to be most efficient tracers of local anthropogenic pollution, especially visible in the surface layer of the shallow site of the lake. Cycling of trace elements between the epilimnion and hypolimnion is tightly linked to dissolved organic matter speciation and size fractionation due to the dominance of organic and organo-ferric colloids. The capacity of lake self-purification depends on the ratio of primary productivity to mineralization of organic matter. This ratio remained >1 both during winter and summer periods, which suggests a high potential of lake recovery from the input of allochthonous dissolved organic matter and local anthropogenic pollution.

  19. Spatial-temporal variability in diazotroph assemblages in Chesapeake Bay using an oligonucleotide nifH microarray.

    Science.gov (United States)

    Moisander, Pia H; Morrison, Amanda E; Ward, Bess B; Jenkins, Bethany D; Zehr, Jonathan P

    2007-07-01

    The distribution of nitrogen-fixing microorganisms in the Chesapeake Bay was investigated using fingerprints from a nifH microarray comprised of 706 60-mer oligonucleotide nifH probes representing cultivated organisms and environmental clones from different nifH clusters. Diverse nifH targets, amplified from samples using degenerate nifH primers, were detected in water column and sediment samples collected in April and October, 2001-2002. Total nifH richness and diversity (Simpson's and Shannon indices) were highest at the most riverine, oligohaline North Bay station. In most samples, the highest diversity was in nifH Cluster 3, which includes many anaerobes, while Cluster 1 (alpha-, beta- gamma- Proteobacteria, Cyanobacteria) targets had the greatest microarray signal intensities. In a multidimensional scaling analysis, deep water communities from April and October were similar within each of the sampling sites, while the surface communities had more variability. Diazotroph communities in the water column in the North Bay were distinct from the Mid- and South Bay communities, and there was a gradual change in sediment diazotroph assemblages from the North to the South Bay. Diazotrophic assemblages from the majority of the water column samples from the Mid- and South Bay clustered with the sediment assemblage in Mid-Bay. Dissolved inorganic nitrogen, salinity, dissolved organic carbon and dissolved organic phosphorus had a significant relationship with the diazotrophic bacterioplankton community. Higher diversity in the freshwater end of the system may reflect variability in disturbance rates and environmental conditions such as forms and concentrations of organic matter, nutrients and oxygen. PMID:17564615

  20. Glyphosate input modifies microbial community structure in clear and turbid freshwater systems.

    Science.gov (United States)

    Pizarro, H; Vera, M S; Vinocur, A; Pérez, G; Ferraro, M; Menéndez Helman, R J; Dos Santos Afonso, M

    2016-03-01

    Since it was commercially introduced in 1974, glyphosate has been one of the most commonly used herbicides in agriculture worldwide, and there is growing concern about its adverse effects on the environment. Assuming that glyphosate may increase the organic turbidity of water bodies, we evaluated the effect of a single application of 2.4 ± 0.1 mg l(-1) of glyphosate (technical grade) on freshwater bacterioplankton and phytoplankton (pico, micro, and nanophytoplankton) and on the physical and chemical properties of the water. We used outdoor experimental mesocosms under clear and oligotrophic (phytoplanktonic chlorophyll a = 2.04 μg l(-1); turbidity = 2.0 NTU) and organic turbid and eutrophic (phytoplanktonic chlorophyll a = 50.3 μg l(-1); turbidity = 16.0 NTU) scenarios. Samplings were conducted at the beginning of the experiment and at 1, 8, 19, and 33 days after glyphosate addition. For both typologies, the herbicide affected the abiotic water properties (with a marked increase in total phosphorus), but it did not affect the structure of micro and nanophytoplankton. In clear waters, glyphosate treatment induced a trend toward higher bacteria and picoeukaryotes abundances, while there was a 2 to 2.5-fold increase in picocyanobacteria number. In turbid waters, without picoeukaryotes at the beginning of the experiment, glyphosate decreased bacteria abundance but increased the number of picocyanobacteria, suggesting a direct favorable effect. Moreover, our results show that the impact of the herbicide was observed in microorganisms from both oligo and eutrophic conditions, indicating that the impact would be independent of the trophic status of the water body. PMID:26552793

  1. Cultivation and biochemical characterization of heterotrophic bacteria associated with phytoplankton bloom in the Amundsen sea polynya, Antarctica

    Science.gov (United States)

    Choi, Seon-Bin; Kim, Jong-Geol; Jung, Man-Young; Kim, So-Jeong; Min, Ui-Gi; Si, Ok-Ja; Park, Soo-Je; Yeon Hwang, Chung; Park, Jisoo; Lee, SangHoon; Rhee, Sung-Keun

    2016-01-01

    Polynyas are a key ecosystem for carbon cycling in the Antarctic Ocean due to the intensive primary production. Most of the knowledge regarding the bacterioplankton community in the Antarctic Ocean that is responsible for re-mineralization of fixed carbon comes from metagenomic analyses. Here, the extinction-dilution method was used to obtain representative heterotrophs from a polynya in the Amundsen Sea, Antarctica, and their biochemical potential for carbon re-mineralization were assessed. All 23 strains have close relatives belonging to type strains within the following genera (number of strains; % 16S rRNA gene sequence similarity): Bizionia (4; >97.8%), Leeuwenhoekiella (1; 96.2%), Pseudoalteromonas (14; >98.5%), Pseudomonas (1; 99.4%) and Sulfitobacter (3; 100%), which were also observed in 454 pyrosequencing-based analysis of 16S rRNA gene sequences of the polynya. Although sequence reads related to Polaribacter were the most common, Polaribacter strains could only be obtained from colonies cultured on agar plates. The strain of Leeuwenhoekiella showed a prominent ability in hydrolyzing diverse esters, amides, and glycosides while the strains of Pseudoalteromonas, Polaribacter, and Bizionia showed extracellular enzyme activities only on a narrow range of amides. The strains of Leeuwenhoekiella, Pseudoalteromonas, and Sulfitobacter utilized various labile carbon sources: carbohydrates, organic acids, amino acids, and peptides. The most frequent isolates, strains of Pseudoaltermonas, showed marked differences in terms of their potential to utilize different types of labile carbon sources, which may reflect high genomic diversity. The strains of Bizionia and Pseudomonas did not utilize carbohydrates. Unique biochemical properties associated with extracellular hydrolase activities and labile carbon utilization were revealed for dominant culturable heterotrophs which gives insights into their roles in active re-mineralization of fixed carbons in polynya.

  2. Structures of dimethylsulfoniopropionate-dependent demethylase from the marine organism Pelagabacter ubique

    Energy Technology Data Exchange (ETDEWEB)

    Schuller, David J.; Reisch, Chris R.; Moran, Mary Ann; Whitman, William B.; Lanzilotta, William N. (Cornell); (Georgia)

    2012-01-20

    Dimethylsulfoniopropionate (DMSP) is a ubiquitous algal metabolite and common carbon and sulfur source for marine bacteria. DMSP is a precursor for the climatically active gas dimethylsulfide that is readily oxidized to sulfate, sulfur dioxide, methanesulfonic acid, and other products that act as cloud condensation nuclei. Although the environmental importance of DMSP metabolism has been known for some time, the enzyme responsible for DMSP demethylation by marine bacterioplankton, dimethylsufoniopropionate-dependent demethylase A (DmdA, EC 2.1.1.B5), has only recently been identified and biochemically characterized. In this work, we report the structure for the apoenzyme DmdA from Pelagibacter ubique (2.1 {angstrom}), as well as for DmdA co-crystals soaked with substrate DMSP (1.6 {angstrom}) or the cofactor tetrahydrofolate (THF) (1.6 {angstrom}). Surprisingly, the overall fold of the DmdA is not similar to other enzymes that typically utilize the reduced form of THF and in fact is a triple domain structure similar to what has been observed for the glycine cleavage T protein or sarcosine oxidase. Specifically, while the THF binding fold appears conserved, previous biochemical studies have shown that all enzymes with a similar fold produce 5,10-methylene-THF, while DmdA catalyzes a redox-neutral methyl transfer reaction to produce 5-methyl-THF. On the basis of the findings presented herein and the available biochemical data, we outline a mechanism for a redox-neutral methyl transfer reaction that is novel to this conserved THF binding domain.

  3. Combined analyses of the ITS loci and the corresponding 16S rRNA genes reveal high micro- and macrodiversity of SAR11 populations in the Red Sea.

    Directory of Open Access Journals (Sweden)

    David Kamanda Ngugi

    Full Text Available Bacteria belonging to the SAR11 clade are among the most abundant prokaryotes in the pelagic zone of the ocean. 16S rRNA gene-based analyses indicate that they constitute up to 60% of the bacterioplankton community in the surface waters of the Red Sea. This extremely oligotrophic water body is further characterized by an epipelagic zone, which has a temperature above 24 °C throughout the year, and a remarkable uniform temperature (~22 °C and salinity (~41 psu from the mixed layer (~200 m to the bottom at over 2000 m depth. Despite these conditions that set it apart from other marine environments, the microbiology of this ecosystem is still vastly understudied. Prompted by the limited phylogenetic resolution of the 16S rRNA gene, we extended our previous study by sequencing the internal transcribed spacer (ITS region of SAR11 in different depths of the Red Sea's water column together with the respective 16S fragment. The overall diversity captured by the ITS loci was ten times higher than that of the corresponding 16S rRNA genes. Moreover, species estimates based on the ITS showed a highly diverse population of SAR11 in the mixed layer that became diminished in deep isothermal waters, which was in contrast to results of the related 16S rRNA genes. While the 16S rRNA gene-based sequences clustered into three phylogenetic subgroups, the related ITS fragments fell into several phylotypes that showed clear depth-dependent shifts in relative abundances. Blast-based analyses not only documented the observed vertical partitioning and universal co-occurrence of specific phylotypes in five other distinct oceanic provinces, but also highlighted the influence of ecosystem-specific traits (e.g., temperature, nutrient availability, and concentration of dissolved oxygen on the population dynamics of this ubiquitous marine bacterium.

  4. Temporal and spatial variations of low-molecular-weight organic acids in Dianchi Lake, China

    Institute of Scientific and Technical Information of China (English)

    Min Xiao; Fengchang Wu; Runyu Zhang; Liying Wang; Xinqing Li; Rongsheng Huang

    2011-01-01

    Low-molecular-weight organic acids (LMWOAs) in eutrophic lake water of Dianchi,Southwestern China Plateau were investigated diurnally and vertically using ion chromatography.Two profiles (P1 and P2) were studied due to the difference of hydrochemical features.Lactic,formic,pyruvic and oxalic acid were detected as major components at P1 and P2 which were on average 7.98 and 6.53 μmol/L,respectively,corresponding to their proportions of 2.68% and 2.48% relative to DOC.Pyruvic acid was regarded as the uppermost species at PI and P2,reaching up to 3.82 and 3.35 μmol/L and accounting for 47.9% and 51.3%,respectively,in individual TOA.Although humus were of biogenetic production at both sites,the significant negative correlation between diurnal variations of TOAs,fluorescence intensity (FI) of protein-like components and humic-like components at P1 indicated LMWOAs were greatly originated from bacterioplankton excretion and degradation.However,correlations between diurnal variations of humic-like FI and physicochemical parameters demonstrated algal origination of LMWOAs at P2.Although content of humus was high,TOA at P2 was 1.45 μmol/L lower than that at P1,due to the co-influence of more intense photo-oxidation and aggregation at P2.Therefore,TOAs exhibited quite opposite diurnal variation trends of increasing-decreasing and decreasing-increasing at P1 and P2,respectively.Except for impact of solar radiation,bacterial decomposition and assimilation rendered shifts of maximal LMWOAs along water colunm at P1.Covering with massive algae,UV rays penetrated shallower depth that LMWOAs assembled in surface layer water before 18:00 at P2 and represented decreasing profiles.

  5. Leucine aminopeptidase, beta-glucosidase and alkaline phosphatase activity rates and their significance in nutrient cycles in some coastal Mediterranean sites.

    Science.gov (United States)

    Caruso, Gabriella

    2010-01-01

    In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus) and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and beta-glucosidase, beta-GLU) on organic polymers (proteins, organic phosphates and polysaccharides, respectively). Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the "potential" metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and beta-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea) and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. beta-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also in carbon

  6. Seasonal Variation of the Geochemistry and the Effects on the Composition in Microbial Communities Attached to Fraser River Suspended Sediments

    Science.gov (United States)

    Bennett, M. C.; Epp, A.; Luymes, R.; DaSilva, J.; Marsh, S. J.; Gillies, S. L.; Peucker-Ehrenbrink, B.; Voss, B.; Coolen, M.

    2013-12-01

    Studies of the temporal dynamics of microbial communities attached to suspended sediments in the Arctic rivers have revealed systematic seasonal changes in microbial community composition, based on 16S ribosomal DNA (rDNA) sequencing (Crump et al., 2007). A time series investigation of the Fraser River system in British Columbia has been conducted with approximately bi-weekly sampling since (2009). The results show significant seasonal variations in many chemical parameters (e.g. nutrient and major element concentrations). An investigation of microbial diversity in the Fraser River is important to understand linkages between microbial diversity and the biogeochemistry of Fraser River water and the particles it transports. The results are the beginning of data analysis to the framework of annual changes that may pose as a threat to biodiversity. Previous studies have shown that decreases in river microbial biodiversity can be linked to decreases in water quality and changes in seasonal water flow (Brown et al., 2007; Vörösmarty et al., 2010). Analysis of microbial DNA (rDNA) attached to the suspended sediment load has not been conducted before on the Fraser River system. The results from this study will therefore establish a bench-mark against which future changes in the Fraser River basin can be compared, it will also serve as an example of seasonal dynamics in microbial community diversity for comparison with other temperate rivers. Such potential changes are of great significance as the Fraser River system is one of the prime salmon spawning river basins in the world. Brown L. E. et al. (2007) Vulnerability of alpine stream biodiversity to shrinking glaciers and snowpacks. Global Change Biology 13, 958-966. Crump B. C. et al. (2007) Biogeography of bacterioplankton in lakes and streams of an arctic tundra catchment. Ecology 88, 1365-1378. Vörösmarty C. J. et al. (2010) Global threats to human water security and river biodiversity. Nature 467, 555-561.

  7. Microbial Gene Abundance and Expression Patterns across a River to Ocean Salinity Gradient.

    Science.gov (United States)

    Fortunato, Caroline S; Crump, Byron C

    2015-01-01

    Microbial communities mediate the biogeochemical cycles that drive ecosystems, and it is important to understand how these communities are affected by changing environmental conditions, especially in complex coastal zones. As fresh and marine waters mix in estuaries and river plumes, the salinity, temperature, and nutrient gradients that are generated strongly influence bacterioplankton community structure, yet, a parallel change in functional diversity has not been described. Metagenomic and metatranscriptomic analyses were conducted on five water samples spanning the salinity gradient of the Columbia River coastal margin, including river, estuary, plume, and ocean, in August 2010. Samples were pre-filtered through 3 μm filters and collected on 0.2 μm filters, thus results were focused on changes among free-living microbial communities. Results from metagenomic 16S rRNA sequences showed taxonomically distinct bacterial communities in river, estuary, and coastal ocean. Despite the strong salinity gradient observed over sampling locations (0 to 33), the functional gene profiles in the metagenomes were very similar from river to ocean with an average similarity of 82%. The metatranscriptomes, however, had an average similarity of 31%. Although differences were few among the metagenomes, we observed a change from river to ocean in the abundance of genes encoding for catabolic pathways, osmoregulators, and metal transporters. Additionally, genes specifying both bacterial oxygenic and anoxygenic photosynthesis were abundant and expressed in the estuary and plume. Denitrification genes were found throughout the Columbia River coastal margin, and most highly expressed in the estuary. Across a river to ocean gradient, the free-living microbial community followed three different patterns of diversity: 1) the taxonomy of the community changed strongly with salinity, 2) metabolic potential was highly similar across samples, with few differences in functional gene abundance

  8. The Influence of Fluvial Discharge on Pelagic Production in the Gulf of Papua, Northern Coral Sea

    Science.gov (United States)

    Robertson, A. I.; Dixon, P.; Alongi, D. M.

    1998-03-01

    The influence of river discharge on the behaviour of dissolved and particulate nutrients, and patterns of primary and bacterial production, were investigated in the Gulf of Papua, northern Coral Sea. Inshore, close to the mouths of the Fly and Purari Rivers, buoyant plumes of warmer river water, marked by high total suspended solid concentrations and floating plant debris, overlay cooler saline waters, and their movement with the tides results in marked short-term changes in salinity profiles. Mixing of silicate was conservative, but the behaviour of other nutrients (nitrate, DOC, phosphate) indicated biological uptake and/or production and release from particles. DIN:DIP ratios increased slightly into the gulf indicating possible phosphorus limitation to phytoplankton growth in mid-shelf and outer-shelf waters. At the mouth of the Fly Delta and in inshore waters, decreases in phosphate concentration corresponded to increases in standing stocks of chlorophyll a. Primary production rates were river delta and inshore waters. Bacterial production was highly variable (range: 162-886 mgC m -2day -1), but correlated very significantly ( r=0·97) with primary production. Rates of bacterioplankton production nearly equal or exceed primary production rates, indicating that pelagic bacteria in the gulf are utilizing other carbon sources (e.g. riverine DOC and POC) and that gulf waters are net heterotrophic. The pattern of primary production across the estuary—shelf salinity gradient off the southern Papua New Guinea coast is similar to that observed off the Amazon. However, the much lower volume of water exiting the Papuan rivers restricts maximum production to the inshore (<50 km from the coast) rim of the Gulf of Papua. This pattern is mirrored in benthic secondary production indicating close benthic-pelagic coupling.

  9. Description of freshwater bacterial assemblages from the upper paraná river floodpulse system, Brazil.

    Science.gov (United States)

    Lemke, Michael J; Lienau, E Kurt; Rothe, Jean; Pagioro, Thomaz A; Rosenfeld, Jeff; Desalle, Rob

    2009-01-01

    Bacteria were identified from a large, seasonally flooded river (Paraná River, Brazil) and two floodplain habitats that were part of the same river system yet very different in nature: clearwater Garças Lagoon and the highly humic waters of Patos Lagoon. Bacterioplankton were collected during mid-summer (Jan. 2002) from water samples (2 l) filtered first through a 1.2-microm filter then a 0.2-microm membrane filter representing the particle-attached and free-living sub-communities, respectively. DNA was extracted from filters and purified and a 16S rRNA clone library established for each habitat. Over 300 clones were sequenced and checked for similarity to existing 16S sequences in GenBank using the BLAST algorithm with default parameters. Further classification of clones was done using a species "backbone" attachment followed by parsimony analysis. The majority (85%) of sequences, referred to here as operational taxonomic units (OTUs), were most similar to uncultured bacterium 16S sequences. OTUs from each Proteobacteria sub-phylum (alpha, beta, gamma, delta, epsilon) were present in the Upper Paraná River system, as well as members of the Bacteroidetes. The microbial assemblage from Patos Lagoon was least like other samples in that it had no Firmicutes present and was dominated by Actinobacteria. Verrucomicrobia OTUs were only found in the free-living assemblage. This study documents the presence of globally distributed phyla in Upper Paraná River and taxa unique to habitat and particle attachment. PMID:18587611

  10. Heterotrophic bacterial production: Relationships to biological and abiological factors in estuarine environments

    Energy Technology Data Exchange (ETDEWEB)

    Koepfler, E.T.

    1989-01-01

    Ecotoxicological effects of creosote contamination on benthic bacterial communities in the Elizabeth River, Virginia were investigated using both structural an functional microbial parameters. Results indicated that cell specific and total heterotrophic bacterial production parameters were depressed in a dose-dependent manner with increasing sediment PAH concentrations. Toxicity effects upon production were modified by temporal trends associated with temperature as well as spatial sediment characteristics. Of the parameters employed, the tritiated thymidine production assay was found to be the most sensitive for detection of ecotoxicological effects. Bacterial abundance and production were examined during a destratification event in the lower James River, Virginia. Bacterial abundance, although significantly different between stations, did not change over the study. Bacterial production ({sup 3}H-Tdr incorporation) in surface waters was significantly less during the mixed period 187 {mu}g C{center dot}1-1{center dot} d{sup {minus}1} compared to the most stratified state (324{mu}g C{center dot}1-1{center dot} d{sup {minus}1}). Correlations between bacteria and chlorophyll were diminished during the mixed period. Total and flagellate specific grazing rates upon bacteria were reduced during the onset of destratification. Relationships between bacterial and nutrient parameters also indicated a strong influence of destratification. These results indicate that destratification changes trophic interactions within the microbial loop, which are not necessarily reflected in temporal patterns of bacterial abundance. Bacterioplankton production, and ammonium assimilation and remineralization were examined between April and August 1988 in the lower York River, Va.

  11. Microbial community dynamics based on 16S rRNA gene profiles in a Pacific Northwest estuary and its tributaries.

    Science.gov (United States)

    Bernhard, Anne E; Colbert, Debbie; McManus, James; Field, Katharine G

    2005-03-01

    We analyzed bacterioplankton community structure in Tillamook Bay, Oregon and its tributaries to evaluate phylogenetic variability and its relation to changes in environmental conditions along an estuarine gradient. Using eubacterial primers, we amplified 16S rRNA genes from environmental DNA and analyzed the PCR products by length heterogeneity polymerase chain reaction (LH-PCR), which discriminates products based on naturally occurring length differences. Analysis of LH-PCR profiles by multivariate ordination methods revealed differences in community composition along the estuarine gradient that were correlated with changes in environmental variables. Microbial community differences were also detected among different rivers. Using partial 16S rRNA sequences, we identified members of dominant or unique gene fragment size classes distributed along the estuarine gradient. Gammaproteobacteria and Betaproteobacteria and members of the Bacteroidetes dominated in freshwater samples, while Alphaproteobacteria, Cyanobacteria and chloroplast genes dominated in marine samples. Changes in the microbial communities correlated most strongly with salinity and dissolved silicon, but were also strongly correlated with precipitation. We also identified specific gene fragments that were correlated with inorganic nutrients. Our data suggest that there is a significant and predictable change in microbial species composition along an estuarine gradient, shifting from a more complex community structure in freshwater habitats to a community more typical of open ocean samples in the marine-influenced sites. We also demonstrate the resolution and power of LH-PCR and multivariate analyses to provide a rapid assessment of major community shifts, and show how these shifts correlate with environmental variables. PMID:16329898

  12. Leucine Aminopeptidase, β-Glucosidase and Alkaline Phosphatase Activity Rates and Their Significance in Nutrient Cycles in Some Coastal Mediterranean Sites

    Directory of Open Access Journals (Sweden)

    Gabriella Caruso

    2010-03-01

    Full Text Available In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and β-glucosidase, β-GLU on organic polymers (proteins, organic phosphates and polysaccharides, respectively. Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the “potential” metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and β-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. β-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also

  13. Distribution and culturability of the uncultivated 'AGG58 cluster' of the Bacteroidetes phylum in aquatic environments.

    Science.gov (United States)

    O'Sullivan, Louise A; Fuller, Katherine E; Thomas, Ellen M; Turley, Carol M; Fry, John C; Weightman, Andrew J

    2004-03-01

    Members of the Bacteroidetes phylum are abundant in aquatic habitats when assessed by fluorescent in situ hybridisation and in some 16S rRNA gene libraries. In this study 16S rRNA gene clone libraries were constructed with bacterial primers that amplify Bacteroidetes sequences well (27F, 1492R) from coastal seawater near Plymouth (UK) during a phytoplankton bloom. Most of the clones (66%, 106/160) affiliated with the Bacteroidetes phylum, and of these 62% (66/106; or 41% 66/160 of the entire library) clustered with marine bacterioplankton clones env.agg58, Arctic97A-17, CF17, CF96 and CF101. This phylogenetic branch of Bacteroidetes was designated the 'AGG58 cluster', and its presence in various aquatic environments was investigated. Two pairs of AGG58-specific 16S rRNA-gene-targeted polymerase chain reaction (PCR) primers were designed and successfully used to detect the cluster in DNA extracts from three UK coastal seawater sites, and from freshwater River Taff epilithon. In addition, 600 putative Bacteroidetes strains were isolated from these sites on relatively high-nutrient agar media. AGG58 cluster specific probes were used to screen the amplified 16S rRNA gene products from the isolates, but no members of the AGG58 cluster were discovered. The least specific probe hybridised with one River Taff water isolate (RW262 NCIMB 13979) which formed a monophyletic group with the genera Crocinitomix, Brumimicrobium and Cryomorpha of the family Cryomorphaceae in the Bacteroidetes phylum. RW262 probably represents the first isolate of a new genus within this family. This study provides new evidence that the uncultivated AGG58 group is abundant, globally distributed, and can be rapidly detected with the new PCR primers described. PMID:19712324

  14. Heterotrophic bacteria in the northern Adriatic Sea: seasonal changes and ectoenzyme profile.

    Science.gov (United States)

    Zaccone, R; Caruso, G; Calì, C

    2002-01-01

    A seasonal study of the quantitative and qualitative distribution of heterotrophic bacterial community was carried out in the Adriatic Sea between April 1995 and January 1996, in order to evaluate its spatial and temporal variability and metabolic potential in the degradation processes of organic matter. The culturable bacteria (CFU) ranged between 0.1 and 22% of total bacterioplankton with a maximum percentage in surface samples of coastal zones. Their distribution was generally affected by the prevailing hydrological conditions. At the coastal stations about 44-75% of CFU variance could be explained by river runoff. The changes in the composition of heterotrophic bacterial community showed a seasonal succession of main bacterial groups, with a prevalence of Gram negative, non fermenting bacteria in the cold period (April-January) and an increase of Vibrionaccae and pigmented bacteria in summer. The seasonal variations were more important at the stations influenced by rivers than offshore. The bacterial community showed a greater versatility for organic polymers hydrolysis in the offshore station than in the coastal areas. Over 60% of all isolated heterotrophic bacteria expressed peptidase, lipase and phosphatase ectoenzymes activities, in all seasons and showed an increasing trend in warm period (in July October). The alpha- and beta-glucosidase potentials of bacteria were lower (20% on average) and showed different pattern during the year. These results suggest different role of the bacterial community in the decomposition of organic matter in the Adriatic Sea. Since only 20% of bacterial strains expressed glucosidase activity, carbohydrate-rich polymers such as mucilage might accumulate. PMID:12148942

  15. Oceanographic Processes in the Region of Fluvial Influence of the Itajaí-Açu River

    Science.gov (United States)

    Schettini, C. A.; Truccolo, E. C.; Pereira, J.; Rörig, L. R.; Resgalla, C.

    2005-05-01

    The oceanographic processes in the region of fluvial influence (ROFI) of the Itajaí-Açu river were assessed through fourteen monthly surveys from November 2002 until December 2003. The main objective of this study was to investigate the effects of the fluvial riverine in the physical, biogeochemical and biological processes in the ROFI. Twenty eight sampling stations were positioned in five transects oriented in a radial shape from the estuarine mouth, with further two stations in the estuary. The transects length was about of 5-km each, reaching the isobath of 25 m. CTD, turbidity and dissolved oxygen profiles were acquired in all stations. Chlorophyll-a were sampled at surface in all stations. Water samples for determination of suspended particulate matter, dissolved inorganic nutrients, chlorophyll-a, phytoplankton and bacterioplankton were sampled in ten stations at surface and near bottom levels. The water samples stations were taken in selected stations to cover all studied area, where was also sampled zooplankton with a ring net. Current speed and direction were acquired with an ADCP moored about 1.5 km off the estuarine mouth at 10 m deep, from November 2002 until March 2003. The river discharge was below the average during most of the sampling period. Although, low salinity water was a permanent feature in the vicinity of the estuarine mouth. The estuarine plume dispersion was allways to north-northeast, what was observed by surface low salinity and higher concentrations of dissolved inorganic nutrients and chlorophyll-a. Below the surface layer, in all ROFI, the water column was dominated by salinity about of 33, named as Coastal Waters. Oceanic waters (salinity higher than 35) were observed only during the summer, with presence of Tropical Water and South Atlantic Central Water. Currents off the estuarine mouth presented strong low frequency signal, with dominance of longshore orientation. Despite of the limitation of the near surface ADCP data, it

  16. Comparison of lysogeny (prophage induction) in heterotrophic bacterial and Synechococcus populations in the Gulf of Mexico and Mississippi River plume.

    Science.gov (United States)

    Long, Amy; McDaniel, Lauren D; Mobberley, Jennifer; Paul, John H

    2008-02-01

    Lysogeny has been documented as a fundamental process occurring in natural marine communities of heterotrophic and autotrophic bacteria. Prophage induction has been observed to be prevalent during conditions of low host abundance, but factors controlling the process are poorly understood. A research cruise was undertaken to the Gulf of Mexico during July 2005 to explore environmental factors associated with lysogeny. Ambient physical and microbial parameters were measured and prophage induction experiments were performed in contrasting oligotrophic Gulf and eutrophic Mississippi plume areas. Three of 11 prophage induction experiments in heterotrophic bacteria (27%) demonstrated significant induction in response to Mitomycin C. In contrast, there was significant Synechococcus cyanophage induction in seven of nine experiments (77.8%). A strong negative correlation was observed between lysogeny and log-transformed activity measurements for both heterotrophic and autotrophic populations (r=-0.876, P=0.002 and r=-0.815, P=0.025, respectively), indicating that bacterioplankton with low host growth favor lysogeny. Multivariate statistical analyses indicated that ambient level of viral abundance and productivity were inversely related to heterotrophic prophage induction and both factors combined were most predictive of lysogeny (rho=0.899, P=0.001). For Synechococcus, low ambient cyanophage abundance was most predictive of lysogeny (rho=0.862, P=0.005). Abundance and productivity of heterotrophic bacteria was strongly inversely correlated with salinity, while Synechococcus was not. This indicated that heterotrophic bacterial populations were well adapted to the river plume environments, thus providing a possible explanation for differences in prevalence of lysogeny observed between the two populations. PMID:18049460

  17. Bioluminescent bacteria as indicators of chemical contamination of coastal waters.

    Science.gov (United States)

    Frischer, M E; Danforth, J M; Foy, T F; Juraske, R

    2005-01-01

    The ratio of bioluminescent to total bacteria (bioluminescent ratio, BLR) as an indicator of a variety of types of anthropogenic contamination of estuarine ecosystems was evaluated through a series of laboratory and field studies. Laboratory studies indicated that the BLR of natural bacterioplankton communities was proportionally reduced in the presence of a number of contaminants including diesel fuel and saltmarsh sediments co-contaminated with mercury and polychlorinated biphenyls (PCBs). Bioluminescent ratio inhibition was observed after short-term exposure to a contaminant suggesting a physiological rather than a population response of native microbial communities. Simulated eutrophication did not suppress the BLR. Field observations of the BLR were conducted weekly for a 2-yr period in the Skidaway River estuary, Georgia, USA. These observations revealed considerable seasonal variability associated with the BLR. Bioluminescent ratios were highest during the summer (25 +/- 15%), lower in the fall (6 +/- 5%) and spring (3 +/- 2%), and near zero during the winter. Although the BLR was not significantly correlated to salinity at a single site (Skidaway River estuary), the BLR was significantly correlated with salinity when sites within the same estuary system were compared (r2 = 0.93). Variation in BLR was not correlated to standard bacteriological indicators of water quality including total and fecal coliform bacteria. Comparison of the BLR from impacted and pristine estuarine sites during the fall suggested that anthropogenically impacted sites exhibited lower BLR than predicted from salinity versus BLR relationships developed in pristine systems. These observations suggest that the BLR could be used as a simple and reliable initial indicator of chemical contamination of estuarine systems resulting from human activity. PMID:15998855

  18. The Source and Age of C Respired in lakes and streams: Implications for the Terrigenous C Budget

    Science.gov (United States)

    McCallister, L.; Del Giorgio, P. A.

    2006-12-01

    Biologically carbon is exchanged between terrigenous and atmospheric ecosystems though the removal of atmospheric CO2 by photosynthesis, its storage in organic form and its subsequent return through the respiratory pathways of terrigenous autotrophic and heterotrophic respiration and biomass burning. We credit an additional respiratory pathway recently gaining quantitative significance in the exchange of C between land and air: the respiration of terrigenous C in inland aquatic system. Positive and sustained pCO2 excursions in lakes, rivers and streams result in a significant outgassing of CO2 from inland aquatic systems. Aquatic respiration of this terrigenous organic carbon (OC) is the sole biological process linking the aquatic, terrigenous and atmospheric biospheres. We measured the stable C and radiocarbon isotopic signatures of bulk organic and inorganic carbon pools and compared these values to isotopic signatures of bacterial respiratory CO2 recovered from short term incubations in order to apportion both the source and age of OC respired by bacterioplankton in the lakes and streams from the Eastern Townships of Québec. These data are the first empirical determination of the age of C respired in aquatic systems. CO2 flux measurements alone do not adequately depict the spatial and temporal connections between biospheres as both the source (watershed vs aquatic primary production) and age of C processed have significantly different consequences for terrigenous and aquatic C budgets and how these systems may respond to current and future land use and climate changes. Our data suggest that C fixed 1000-3000 years BP on land fuels a substantial portion of aquatic respiration in lakes and streams. At the global scale this biological mobilization of pre-aged C into an active component of the C cycle represents a significant overestimation of C stored in intermediate soil reservoirs.

  19. From bacteria to piscivorous fish: estimates of whole-lake and component-specific metabolism with an ecosystem approach.

    Directory of Open Access Journals (Sweden)

    Fabien Cremona

    Full Text Available The influence of functional group specific production and respiration patterns on a lake's metabolic balance remains poorly investigated to date compared to whole-system estimates of metabolism. We employed a summed component ecosystem approach for assessing lake-wide and functional group-specific metabolism (gross primary production (GPP and respiration (R in shallow and eutrophic Lake Võrtsjärv in central Estonia during three years. Eleven functional groups were considered: piscivorous and benthivorous fish; phyto-, bacterio-, proto- and metazooplankton; benthic macroinvertebrates, bacteria and ciliates; macrophytes and their associated epiphytes. Metabolism of these groups was assessed by allometric equations coupled with daily records of temperature and hydrology of the lake and measurements of food web functional groups biomass. Results revealed that heterotrophy dominated most of the year, with a short autotrophic period observed in late spring. Most of the metabolism of the lake could be attributed to planktonic functional groups, with phytoplankton contributing the highest share (90% of GPP and 43% of R. A surge of protozooplankton and bacterioplankton populations forming the microbial loop caused the shift from auto- to heterotrophy in midsummer. Conversely, the benthic functional groups had overall a very small contribution to lake metabolism. We validated our ecosystem approach by comparing the GPP and R with those calculated from O2 measurements in the lake. Our findings are also in line with earlier productivity studies made with 14C or chlorophyll a (chl-a based equations. Ideally, the ecosystem approach should be combined with diel O2 approach for investigating critical periods of metabolism shifts caused by dynamics in food-web processes.

  20. Turbulence-driven shifts in holobionts and planktonic microbial assemblages in St Peter & St Paul Archipelago, Mid-Atlantic Ridge, Brazil

    Directory of Open Access Journals (Sweden)

    Ana Paula B. Moreira

    2015-10-01

    Full Text Available The aim of this study was to investigate the planktonic and the holobiont Madracis decactis (Scleractinia microbial diversity along a turbulence-driven upwelling event, in the world´s most isolated tropical island, St Peter and St Paul Archipelago (SPSPA, Brazil. Twenty one metagenomes were obtained for seawater (N=12, healthy and bleached holobionts (N=9 before, during and after the episode of high seawater turbulence and upwelling. Microbial assemblages differed between low turbulence-low nutrient (LLR and high-turbulence-high nutrient (HHR regimes in seawater. During LLR there was a balance between autotrophy and heterotrophy in the bacterioplankton and the ratio cyanobacteria:heterotrophs ~1 (C:H. Prochlorales, unclassified Alphaproteobacteria and Euryarchaeota were the dominant bacteria and archaea, respectively. Basic metabolisms and cyanobacterial phages characterized the LLR. During HHR C:H << 0.05 and Gammaproteobacteria approximated 50% of the most abundant organisms in seawater. Alteromonadales, Oceanospirillales and Thaumarchaeota were the dominant bacteria and archaea. Prevailing metabolisms were related to membrane transport, virulence, disease and defense. Phages targeting heterotrophs and virulence factor genes characterized HHR. Shifts were also observed in coral microbiomes, according to both annotation–indepent and -dependent methods. HHR bleached corals metagenomes were the most dissimilar and could be distinguished by their di- and tetranucleotides frequencies, Iron Acquision metabolism and virulence genes, such as V. cholerae-related virulence factors. The healthy coral holobiont was shown to be less sensitive to transient seawater-related perturbations than the diseased animals. A conceptual model for the turbulence-induced shifts is put forward.

  1. Assembling the marine metagenome, one cell at a time.

    Directory of Open Access Journals (Sweden)

    Tanja Woyke

    taxa from a complex microbial community of marine bacterioplankton. A combination of single cell genomics and metagenomics enabled us to analyze the genome content, metabolic adaptations, and biogeography of these taxa.

  2. Combined analyses of the ITS loci and the corresponding 16S rRNA genes reveal high micro- and macrodiversity of SAR11 populations in the Red Sea.

    KAUST Repository

    Ngugi, David Kamanda

    2012-11-20

    Bacteria belonging to the SAR11 clade are among the most abundant prokaryotes in the pelagic zone of the ocean. 16S rRNA gene-based analyses indicate that they constitute up to 60% of the bacterioplankton community in the surface waters of the Red Sea. This extremely oligotrophic water body is further characterized by an epipelagic zone, which has a temperature above 24 °C throughout the year, and a remarkable uniform temperature (~22 °C) and salinity (~41 psu) from the mixed layer (~200 m) to the bottom at over 2000 m depth. Despite these conditions that set it apart from other marine environments, the microbiology of this ecosystem is still vastly understudied. Prompted by the limited phylogenetic resolution of the 16S rRNA gene, we extended our previous study by sequencing the internal transcribed spacer (ITS) region of SAR11 in different depths of the Red Sea\\'s water column together with the respective 16S fragment. The overall diversity captured by the ITS loci was ten times higher than that of the corresponding 16S rRNA genes. Moreover, species estimates based on the ITS showed a highly diverse population of SAR11 in the mixed layer that became diminished in deep isothermal waters, which was in contrast to results of the related 16S rRNA genes. While the 16S rRNA gene-based sequences clustered into three phylogenetic subgroups, the related ITS fragments fell into several phylotypes that showed clear depth-dependent shifts in relative abundances. Blast-based analyses not only documented the observed vertical partitioning and universal co-occurrence of specific phylotypes in five other distinct oceanic provinces, but also highlighted the influence of ecosystem-specific traits (e.g., temperature, nutrient availability, and concentration of dissolved oxygen) on the population dynamics of this ubiquitous marine bacterium.

  3. Assembling The Marine Metagenome, One Cell At A Time

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Gang [Los Alamos National Laboratory; Han, Shunsheng [Los Alamos National Laboratory; Kiss, Hajnalka [Los Alamos National Laboratory; Saw, Jimmy [Los Alamos National Laboratory; Senin, Pavel [Los Alamos National Laboratory; Woyke, Tanja [DOE JOINT GENOME INAT.; Copeland, Alex [DOE JOINT GENSOME INST.; Gonzalez, Jose [UNIV OF LAGUNA, SPAIN; Chatterji, Sourav [DOE JOINT GENSOME INST.; Cheng, Jan - Fang [DOE JOINT GENSOME INST.; Eisen, Jonathan A [DOE JOINT GENOME INST.; Sieracki, Michael E [UNIV OF CA-DAVIS; Stepanauskas, Ramunas [BIGELOW LAB

    2008-01-01

    microbial community of marine bacterioplankton. A combination of single cell genomics and metagenomics enabled us to analyze the genome content, metabolic adaptations, and biogeography of these taxa.

  4. Assembling the Marine Metagenome, One Cell at a Time

    Energy Technology Data Exchange (ETDEWEB)

    Woyke, Tanja; Xie, Gary; Copeland, Alex; Gonzalez, Jose M.; Han, Cliff; Kiss, Hajnalka; Saw, Jimmy H.; Senin, Pavel; Yang, Chi; Chatterji, Sourav; Cheng, Jan-Fang; Eisen, Jonathan A.; Sieracki, Michael E.; Stepanauskas, Ramunas

    2010-06-24

    taxa from a complex microbial community of marine bacterioplankton. A combination of single cell genomics and metagenomics enabled us to analyze the genome content, metabolic adaptations, and biogeography of these taxa.

  5. Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

    Science.gov (United States)

    Jeanthon, C.; Boeuf, D.; Dahan, O.; Le Gall, F.; Garczarek, L.; Bendif, E. M.; Lehours, A.-C.

    2011-07-01

    Aerobic anoxygenic phototrophic (AAP) bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a), the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 54 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94 %) was affiliated to the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the discrepancies between culture-based and molecular methods, this study highlights the existing gaps in the understanding

  6. Distinct expression of alkaline phosphatase activity in epilimnetic bacteria: Implication for persistent DOC consumption in a P-limited reservoir

    Science.gov (United States)

    Tseng, Y.; Kao, S.; Shiah, F.

    2013-12-01

    In a P-deficient system, P availability usually controls the microbial activity and thus the ecosystem function. Thingstad et al. (1997) first addressed a 'Malfunctioning Microbial-loop' theory, which stated that low bacterial production (BP) caused by insufficient nutrient supply would result in DOC accumulation in an oligotrophic ecosystem. In this study we re-examined the theory by conducting seasonal patterns and correlations among soluble reactive phosphate (SRP) and DOC, microbial abundances (picocyanobacteria, bacteria, and heterotrophic nanoflagellate; HNF) and activities (primary production, bacterial production, and alkaline phosphatase activity; APA) coupled with enzyme-labeled fluorescence (ELF) assays on bacterioplankton in a subtropical reservoir sharing the common features, nitrate-replete and P-deficient, with most natural freshwater system during Oct 2007-Oct 2008. Persistently high APA was recorded during most of time, implying that the system was P-deficient. Size fractionated APA and ELF assay revealed that bacteria were the major APA contributor. However, significantly low epilimnion DOC was recorded during the stratified summer season accompanying with high BP and APA as well as high PP, implying that heterotrophic bacteria can well sustain in P-deficient system by utilizing DOP to rapidly lower down DOC under relatively high PP. Such findings oppose the 'Malfunctioning Microbial-loop' theory. On the other hand, strong epilimnetic DOC accumulation occurred in Oct 2007 under low light and low PP condition accompanying with high abundance of HNF, implying that HNF grazing may contribute to a certain degree of DOC accumulation. Correlation matrix supported our suggestions. This study testified the DOC dynamics in P-deficient ecosystem are tightly coupled with the source (PP and grazing) and sink (BP). We also suggested that in SRP-limited freshwater systems bacteria are capable of breaking down autochthonous DOC to reduce the chance of DOC

  7. Mississippi River Plume Enriches Microbial Diversity in the Northern Gulf of Mexico

    Science.gov (United States)

    Mason, Olivia U.; Canter, Erin J.; Gillies, Lauren E.; Paisie, Taylor K.; Roberts, Brian J.

    2016-01-01

    The Mississippi River (MR) serves as the primary source of freshwater and nutrients to the northern Gulf of Mexico (nGOM). Whether this input of freshwater also enriches microbial diversity as the MR plume migrates and mixes with the nGOM serves as the central question addressed herein. Specifically, in this study physicochemical properties and planktonic microbial community composition and diversity was determined using iTag sequencing of 16S rRNA genes in 23 samples collected along a salinity (and nutrient) gradient from the mouth of the MR, in the MR plume, in the canyon, at the Deepwater Horizon wellhead and out to the loop current. Analysis of these datasets revealed that the MR influenced microbial diversity as far offshore as the Deepwater Horizon wellhead. The MR had the highest microbial diversity, which decreased with increasing salinity. MR bacterioplankton communities were distinct compared to the nGOM, particularly in the surface where Actinobacteria and Proteobacteria dominated, while the deeper MR was also enriched in Thaumarchaeota. Statistical analyses revealed that nutrients input by the MR, along with salinity and depth, were the primary drivers in structuring the microbial communities. These results suggested that the reduced salinity, nutrient enriched MR plume could act as a seed bank for microbial diversity as it mixes with the nGOM. Whether introduced microorganisms are active at higher salinities than freshwater would determine if this seed bank for microbial diversity is ecologically significant. Alternatively, microorganisms that are physiologically restricted to freshwater habitats that are entrained in the plume could be used as tracers for freshwater input to the marine environment. PMID:27458442

  8. Ecosystem element transport model for Lake Eckarfjaerden

    International Nuclear Information System (INIS)

    The ecosystem transport model of elements was developed for Lake Eckarfjaerden located in the Forsmark area in Sweden. Forsmark has currently a low level repository (SFR) and a repository for spent fuel is planned. A large number of data collected during site-investigation program 2002-2009 for planning the repository were available for the creation of the compartment model based on carbon circulation, physical and biological processes (e.g. primary production, consumption, respiration). The model is site-specific in the sense that the food web model is adapted to the actual food web at the site, and most estimates of biomass and metabolic rates for the organisms and meteorological data originate from site data. The functional organism groups of Lake Eckarfjaerden were considered as separate compartments: bacterio-plankton, benthic bacteria, macro-algae, phytoplankton, zooplankton, fish, benthic fauna. Two functional groups of bacteria were taken into account for the reason that they have the highest biomass of all functional groups during the winter, comprising 36% of the total biomass. Effects of ecological parameters, such as bacteria and algae biomass, on redistribution of a hypothetical radionuclide release in the lake were examined. The ecosystem model was used to estimate the environmental transfer of several elements (U, Th, Ra) and their isotopes (U-238, U-234,Th-232, Ra-226) to various aquatic organisms in the lake, using element-specific distribution coefficients for suspended particle and sediment. Results of chemical analyses of the water, sediment and biota were used for model validation. The model gives estimates of concentration factors for fish based on modelling rather on in situ measurement, which reduces the uncertainties for many radionuclides with scarce of data. Document available in abstract form only. (authors)

  9. Microbial Gene Abundance and Expression Patterns across a River to Ocean Salinity Gradient.

    Directory of Open Access Journals (Sweden)

    Caroline S Fortunato

    Full Text Available Microbial communities mediate the biogeochemical cycles that drive ecosystems, and it is important to understand how these communities are affected by changing environmental conditions, especially in complex coastal zones. As fresh and marine waters mix in estuaries and river plumes, the salinity, temperature, and nutrient gradients that are generated strongly influence bacterioplankton community structure, yet, a parallel change in functional diversity has not been described. Metagenomic and metatranscriptomic analyses were conducted on five water samples spanning the salinity gradient of the Columbia River coastal margin, including river, estuary, plume, and ocean, in August 2010. Samples were pre-filtered through 3 μm filters and collected on 0.2 μm filters, thus results were focused on changes among free-living microbial communities. Results from metagenomic 16S rRNA sequences showed taxonomically distinct bacterial communities in river, estuary, and coastal ocean. Despite the strong salinity gradient observed over sampling locations (0 to 33, the functional gene profiles in the metagenomes were very similar from river to ocean with an average similarity of 82%. The metatranscriptomes, however, had an average similarity of 31%. Although differences were few among the metagenomes, we observed a change from river to ocean in the abundance of genes encoding for catabolic pathways, osmoregulators, and metal transporters. Additionally, genes specifying both bacterial oxygenic and anoxygenic photosynthesis were abundant and expressed in the estuary and plume. Denitrification genes were found throughout the Columbia River coastal margin, and most highly expressed in the estuary. Across a river to ocean gradient, the free-living microbial community followed three different patterns of diversity: 1 the taxonomy of the community changed strongly with salinity, 2 metabolic potential was highly similar across samples, with few differences in

  10. Role of environmental factors for the vertical distribution (0–1000 m of marine bacterial communities in the NW Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    J. F. Ghiglione

    2008-12-01

    Full Text Available Bacterioplankton plays a central role in energy and matter fluxes in the sea, yet the factors that constrain its variation in marine systems are still poorly understood. Here we use the explanatory power of direct multivariate gradient analysis to evaluate the driving forces exerted by environmental parameters on bacterial community distribution in the water column. We gathered and analysed data from a one month sampling period from the surface to 1000 m depth at the JGOFS-DYFAMED station (NW Mediterranean Sea. This station is characterized by very poor horizontal advection currents which makes it an ideal model to test hypotheses on the causes of vertical stratification of bacterial communities. Capillary electrophoresis single strand conformation polymorphism (CE-SSCP fingerprinting profiles analyzed using multivariate statistical methods demonstrated a vertical zonation of bacterial assemblages in three layers, above, in or just below the chlorophyll maximum and deeper, that remained stable during the entire sampling period. Through the use of direct gradient multivariate ordination analyses we demonstrate that a complex array of biogeochemical parameters is the driving force behind bacterial community structure shifts in the water column. Physico-chemical parameters such as phosphate, nitrate, salinity and to a lesser extent temperature, oxygen, dissolved organic carbon and photosynthetically active radiation acted in synergy to explain bacterial assemblages changes with depth. Analysis of lipid biomarkers of organic matter sources and fates suggested that bacterial community structure in the surface layers was in part explained by lipids of chloroplast origin. Further detailed analysis of pigment-based phytoplankton diversity gave evidence of a compartmentalized influence of several phytoplankton groups on bacterial community structure in the first 150 m depth.

  11. Co-occurrence patterns in aquatic bacterial communities across changing permafrost landscapes

    Science.gov (United States)

    Comte, J.; Lovejoy, C.; Crevecoeur, S.; Vincent, W. F.

    2016-01-01

    Permafrost thaw ponds and lakes are widespread across the northern landscape and may play a central role in global biogeochemical cycles, yet knowledge about their microbial ecology is limited. We sampled a set of thaw ponds and lakes as well as shallow rock-basin lakes that are located in distinct valleys along a north-south permafrost degradation gradient. We applied high-throughput sequencing of the 16S rRNA gene to determine co-occurrence patterns among bacterial taxa (operational taxonomic units, OTUs), and then analyzed these results relative to environmental variables to identify variables controlling bacterial community structure. Network analysis was applied to identify possible ecological linkages among the bacterial taxa and with abiotic and biotic variables. The results showed an overall high level of shared taxa among bacterial communities within each valley; however, the bacterial co-occurrence patterns were non-random, with evidence of habitat preferences. There were taxonomic differences in bacterial assemblages among the different valleys that were statistically related to dissolved organic carbon concentration, conductivity and phytoplankton biomass. Co-occurrence networks revealed complex interdependencies within the bacterioplankton communities and showed contrasting linkages to environmental conditions among the main bacterial phyla. The thaw pond networks were composed of a limited number of highly connected taxa. This "small world network" property would render the communities more robust to environmental change but vulnerable to the loss of microbial "keystone species". These highly connected nodes (OTUs) in the network were not merely the numerically dominant taxa, and their loss would alter the organization of microbial consortia and ultimately the food web structure and functioning of these aquatic ecosystems.

  12. Characterization of biocenoses in the storage reservoirs of liquid radioactive wastes of Mayak PA. Initial descriptive report.

    Science.gov (United States)

    Pryakhin, E A; Mokrov, Yu G; Tryapitsina, G A; Ivanov, I A; Osipov, D I; Atamanyuk, N I; Deryabina, L V; Shaposhnikova, I A; Shishkina, E A; Obvintseva, N A; Egoreichenkov, E A; Styazhkina, E V; Osipova, O F; Mogilnikova, N I; Andreev, S S; Tarasov, O V; Geras'kin, S A; Trapeznikov, A V; Akleyev, A V

    2016-01-01

    As a result of operation of the Mayak Production Association (Mayak PA), Chelyabinsk Oblast, Russia, an enterprise for production and separation of weapon-grade plutonium in the Soviet Union, ecosystems of a number of water bodies have been radioactively contaminated. The article presents information about the current state of ecosystems of 6 special industrial storage reservoirs of liquid radioactive waste from Mayak PA: reservoirs R-3, R-4, R-9, R-10, R-11 and R-17. At present the excess of the radionuclide content in the water of the studied reservoirs and comparison reservoirs (Shershnyovskoye and Beloyarskoye reservoirs) is 9 orders of magnitude for (90)Sr and (137)Cs, and 6 orders of magnitude for alpha-emitting radionuclides. According to the level of radioactive contamination, the reservoirs of the Mayak PA could be arranged in the ascending order as follows: R-11, R-10, R-4, R-3, R-17 and R-9. In 2007-2012 research of the status of the biocenoses of these reservoirs in terms of phytoplankton, zooplankton, bacterioplankton, zoobenthos, aquatic plants, ichthyofauna, avifauna parameters was performed. The conducted studies revealed decrease in species diversity in reservoirs with the highest levels of radioactive and chemical contamination. This article is an initial descriptive report on the status of the biocenoses of radioactively contaminated reservoirs of the Mayak PA, and is the first article in a series of publications devoted to the studies of the reaction of biocenoses of the fresh-water reservoirs of the Mayak PA to a combination of natural and man-made factors, including chronic radiation exposure. PMID:26094572

  13. Contribution of picoplankton to the total particulate organic carbon (POC concentration in the eastern South Pacific

    Directory of Open Access Journals (Sweden)

    C. Grob

    2007-05-01

    Full Text Available Prochlorococcus, Synechococcus, picophytoeukaryotes and bacterioplankton abundances and contributions to the total particulate organic carbon concentration (POC, derived from the total particle beam attenuation coefficient (cp, were determined across the eastern South Pacific between the Marquesas Islands and the coast of Chile. All flow cytometrically derived abundances decreased towards the hyper-oligotrophic centre of the gyre and were highest at the coast, except for Prochlorococcus, which is not detected under eutrophic conditions. Temperature and nutrient availability appeared important in modulating picophytoplankton abundance, according to the prevailing trophic conditions. Although the non-vegetal particles tended to dominate the cp signal everywhere along the transect (50 to 83%, this dominance seemed to weaken from oligo- to eutrophic conditions, the contributions by vegetal and non-vegetal particles being about equal under mature upwelling conditions. Spatial variability in the vegetal compartment was more important than the non-vegetal one in shaping the water column particulate attenuation coefficient. Spatial variability in picophytoplankton biomass could be traced by changes in both Tchla and cp. Finally, picophytoeukaryotes contributed with ~38% on average to the total integrated phytoplankton carbon biomass or vegetal attenuation signal along the transect, as determined by direct size measurements on cells sorted by flow cytometry and optical theory. The role of picophytoeukaryotes in carbon and energy flow would therefore be very important, even under hyper-oligotrophic conditions.

  14. Taxonomic and Environmental Variability in the Elemental Composition and Stoichiometry of Individual Dinoflagellate and Diatom Cells from the NW Mediterranean Sea.

    Directory of Open Access Journals (Sweden)

    Mariona Segura-Noguera

    Full Text Available Here we present, for the first time, the elemental concentration, including C, N and O, of single phytoplankton cells collected from the sea. Plankton elemental concentration and stoichiometry are key variables in phytoplankton ecophysiology and ocean biogeochemistry, and are used to link cells and ecosystems. However, most field studies rely on bulk techniques that overestimate carbon and nitrogen because the samples include organic matter other than plankton organisms. Here we used X-ray microanalysis (XRMA, a technique that, unlike bulk analyses, gives simultaneous quotas of C, N, O, Mg, Si, P, and S, in single-cell organisms that can be collected directly from the sea. We analysed the elemental composition of dinoflagellates and diatoms (largely Chaetoceros spp. collected from different sites of the Catalan coast (NW Mediterranean Sea. As expected, a lower C content is found in our cells compared to historical values of cultured cells. Our results indicate that, except for Si and O in diatoms, the mass of all elements is not a constant fraction of cell volume but rather decreases with increasing cell volume. Also, diatoms are significantly less dense in all the measured elements, except Si, compared to dinoflagellates. The N:P ratio of both groups is higher than the Redfield ratio, as it is the N:P nutrient ratio in deep NW Mediterranean Sea waters (N:P = 20-23. The results suggest that the P requirement is highest for bacterioplankton, followed by dinoflagellates, and lowest for diatoms, giving them a clear ecological advantage in P-limited environments like the Mediterranean Sea. Finally, the P concentration of cells of the same genera but growing under different nutrient conditions was the same, suggesting that the P quota of these cells is at a critical level. Our results indicate that XRMA is an accurate technique to determine single cell elemental quotas and derived conversion factors used to understand and model ocean biogeochemical

  15. The Trophic Fate of Shrimp Farm Effluent in Mangrove Creeks of North Queensland, Australia

    Science.gov (United States)

    Mckinnon, A. D.; Trott, L. A.; Cappo, M.; Miller, D. K.; Duggan, S.; Speare, P.; Davidson, A.

    2002-10-01

    Zooplankton and fish communities in mangrove creeks removed materials originating from the discharge of effluent from ponds used for shrimp aquaculture at two commercial farms in North Queensland, Australia. Undisturbed mangrove creeks were compared to creeks receiving effluent from shrimp farms. Shrimp farm effluent was rich in chlorophyll a (56 μg l -1) and bacteria (1·9×10 6 cells ml -1). The potential grazing impact of ciliates was higher than that of copepod nauplii or copepodids upstream. In contrast, copepods were more important downstream. Carbon removal by ciliates and copepods accounted for as much as 85% of primary production during non-discharge periods, but was less important during discharge periods. Direct measurement of microzooplankton grazing with the dilution method indicated that growth and grazing were usually in balance, but during pond discharge periods microzooplankton grazing removed >120% of primary production and 117-266% of bacterioplankton production in the mixed lower reaches of the creeks and immediately offshore. Grazing by bacterivores was saturated in the upper reaches of the creeks, but was very high near the creek mouths, where the range of specific grazing rates was 5·2-11·8 d -1. Baitfish juveniles were abundant in the creek systems, and fed either directly on macro-particulates by indiscriminate filter feeding, or by selective feeding on microfauna. Trophic processes and their associated respiratory losses are instrumental in the assimilation and dissipation of effluent materials within the creek system, and are responsible for returning concentrations of bio-available materials to ambient levels. The sustainable use of coastal environments depends to a large degree on understanding and regulating the impacts from activities within the catchment. This research provides environmental managers with direct evidence that, under certain conditions, perturbations in creek water quality and biota originating from shrimp farm

  16. Fishery impacts of peat production

    International Nuclear Information System (INIS)

    The total area of Finland's peat mining areas is approx. 60 000 ha. Increase in runoff from peat mining areas and changes in the quality of the runoff water, such as rises in solid matter, humus and nutrient content, result in a higher load on the lakes and rivers downstream peat mining areas. Loading from peat mining areas has been found to increase the bacterioplankton densities and change the species composition of phytoplankton in watercourses. Periphytic biomass has increased but zooplankton biomass and diversity have decreased. Corresponding changes and decreases in the number of species have also been observed in the bottom fauna of flowing waters. The loading caused by peat mining affects the fish stocks either directly or via changes in reproduct conditions and the availability of food organisms. Direct effects can be revealed as withdrawal of fish, their weakened condition and increased susceptibility to diseases, tainting or, in the worst case, even fish kills. Both organic and inorganic solid matter loading which deposits on the bottom have the most pronounced effects on fish reproduction and bottom fauna used as their food. Soiling of nets and changes in the condition of the fishing areas have a detrimental effect on fisheries. The changes that take place in the fish stocks are affected by the nature of the water system, the size of the peat mining areas and their location within the catchment area, as well as the quantity and timing of load coming from the peat mining areas. These can be influenced through technical water protection measures

  17. How do Bacteria Adapt to the Red Sea? Cultivation and Genomic and Physiological Characterization of Oligotrophic Bacteria of the PS1, OM43, and SAR11 Clades

    KAUST Repository

    Jimenez Infante, Francy M.

    2015-05-01

    isolates from the Ia (RS39) and Ib (RS40) subgroups, principally revealed unique putative systems for iron uptake and myo-inositol utilization in RS39, and a potential phosphonates biosynthetic pathway present in RS40. The findings presented here reflect how environments influence the genomic repertoire of microbial communities and shows novel metabolisms and putative pathways as unique adaptive qualities in diverse microbes encompassing from rare to predominant bacterioplankton groups from the Red Sea.

  18. Open source approaches to establishing Roseobacter clade bacteria as synthetic biology chassis for biogeoengineering

    Science.gov (United States)

    Boeing, Philipp; Wolfenden, Bethan; Smith, Patrick; Beaufoy, William; Rose, Simon; Ratisai, Tonderai; Zaikin, Alexey

    2016-01-01

    Aim. The nascent field of bio-geoengineering stands to benefit from synthetic biologists’ efforts to standardise, and in so doing democratise, biomolecular research methods. Roseobacter clade bacteria comprise 15–20% of oceanic bacterio-plankton communities, making them a prime candidate for establishment of synthetic biology chassis for bio-geoengineering activities such as bioremediation of oceanic waste plastic. Developments such as the increasing affordability of DNA synthesis and laboratory automation continue to foster the establishment of a global ‘do-it-yourself’ research community alongside the more traditional arenas of academe and industry. As a collaborative group of citizen, student and professional scientists we sought to test the following hypotheses: (i) that an incubator capable of cultivating bacterial cells can be constructed entirely from non-laboratory items, (ii) that marine bacteria from the Roseobacter clade can be established as a genetically tractable synthetic biology chassis using plasmids conforming to the BioBrickTM standard and finally, (iii) that identifying and subcloning genes from a Roseobacter clade species can readily by achieved by citizen scientists using open source cloning and bioinformatic tools. Method. We cultivated three Roseobacter species, Roseobacter denitrificans, Oceanobulbus indolifexand Dinoroseobacter shibae. For each species we measured chloramphenicol sensitivity, viability over 11 weeks of glycerol-based cryopreservation and tested the effectiveness of a series of electroporation and heat shock protocols for transformation using a variety of plasmid types. We also attempted construction of an incubator-shaker device using only publicly available components. Finally, a subgroup comprising citizen scientists designed and attempted a procedure for isolating the cold resistance anf1 gene from Oceanobulbus indolifexcells and subcloning it into a BioBrickTM formatted plasmid. Results. All species were stable

  19. Effects of increased solar ultraviolet radiation on biogeochemical cycles

    International Nuclear Information System (INIS)

    Increases in solar UV radiation could affect terrestrial and aquatic biogeochemical cycles thus altering both sources and sinks of greenhouse and chemically important trace gases (e.g., carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulfide (COS). In terrestrial ecosystems, increased UV-B could modify both the production and decomposition of plant matter with concomitant changes in the uptake and release of atmospherically important trace gases. Decomposition processes can be accelerated when UV-B photodegrades surface litter, or retarded when the dominant effect involves changes in the chemical composition of living tissues that reduce the biodegradability of buried litter. These changes in decomposition can affect microbial production of CO2 and other trace gases and also may affect the availability of nutrients essential for plant growth. Primary production can be reduced by enhanced UV-B, but the effect is variable between species and even cultivars of some crops. Likewise, the effects of enhanced UV-B on photoproduction of CO from plant matter is species-dependent and occurs more efficiently from dead than from living matter. Aquatic ecosystems studies in several different locations have shown that reductions in current levels of solar UV-B result in enhanced primary production, and Antarctic experiments under the ozone hole demonstrated that primary production is inhibited by enhanced UV-B. In addition to its effects on primary production, solar UV radiation can reduce bacterioplankton growth in the upper ocean with potentially important effects on marine biogeochemical cycles. Decomposition processes can be retarded when bacterial activity is suppressed by enhanced UV-B radiation or stimulated when solar UV radiation photodegrades aquatic dissolved organic matter. Photodegradation of DOM results in loss of UV absorption and formation of dissolved inorganic carbon, CO, and organic substrates that are readily mineralized or taken up by aquatic

  20. Phytoplankton diversity and productivity in a highly turbid, tropical coastal system (Bach Dang Estuary, Vietnam)

    Science.gov (United States)

    Rochelle-Newall, E. J.; Chu, V. T.; Pringault, O.; Amouroux, D.; Arfi, R.; Bettarel, Y.; Bouvier, T.; Bouvier, C.; Got, P.; Nguyen, T. M. H.; Mari, X.; Navarro, P.; Duong, T. N.; Cao, T. T. T.; Pham, T. T.; Ouillon, S.; Torréton, J.-P.

    2011-01-01

    The factors controlling estuarine phytoplankton diversity and production are relatively well known in temperate systems. Less however is known about the factors affecting phytoplankton community distribution in tropical estuaries. This is surprising given the economic and ecological importance of these large, deltaic ecosystems, such as are found in South East Asia. Here we present the results from an investigation into the factors controlling phytoplankton distribution and phytoplankton-bacterial coupling in the Bach Dang Estuary, a sub-estuary of the Red River system, in Northern Vietnam. Phytoplankton diversity and primary and bacterial production, nutrients and metallic contaminants (mercury and organotin) were measured during two seasons: wet (July 2008) and dry (March 2009). Phytoplankton community composition differed between the two seasons with only a 2% similarity between July and March. The large spatial extent and complexity of defining the freshwater sources meant that simple mixing diagrams could not be used in this system. We therefore employed multivariate analyses to determine the factors influencing phytoplankton community structure. Salinity and suspended particulate matter were important factors in determining phytoplankton distribution, particularly during the wet season. We also show that phytoplankton community structure is probably influenced by the concentrations of mercury species (inorganic mercury and methyl mercury in both the particulate and dissolved phases) and of tri-, di, and mono-butyl tin species found in this system. Freshwater phytoplankton community composition was associated with dissolved methyl mercury and particulate inorganic mercury concentrations during the wet season, whereas, during the dry season, dissolved methyl mercury and particulate butyl tin species were important factors for the discrimination of the phytoplankton community structure. Phytoplankton-bacterioplankton coupling was also investigated during both

  1. Open source approaches to establishing Roseobacter clade bacteria as synthetic biology chassis for biogeoengineering.

    Science.gov (United States)

    Borg, Yanika; Grigonyte, Aurelija Marija; Boeing, Philipp; Wolfenden, Bethan; Smith, Patrick; Beaufoy, William; Rose, Simon; Ratisai, Tonderai; Zaikin, Alexey; Nesbeth, Darren N

    2016-01-01

    Aim. The nascent field of bio-geoengineering stands to benefit from synthetic biologists' efforts to standardise, and in so doing democratise, biomolecular research methods. Roseobacter clade bacteria comprise 15-20% of oceanic bacterio-plankton communities, making them a prime candidate for establishment of synthetic biology chassis for bio-geoengineering activities such as bioremediation of oceanic waste plastic. Developments such as the increasing affordability of DNA synthesis and laboratory automation continue to foster the establishment of a global 'do-it-yourself' research community alongside the more traditional arenas of academe and industry. As a collaborative group of citizen, student and professional scientists we sought to test the following hypotheses: (i) that an incubator capable of cultivating bacterial cells can be constructed entirely from non-laboratory items, (ii) that marine bacteria from the Roseobacter clade can be established as a genetically tractable synthetic biology chassis using plasmids conforming to the BioBrick(TM) standard and finally, (iii) that identifying and subcloning genes from a Roseobacter clade species can readily by achieved by citizen scientists using open source cloning and bioinformatic tools. Method. We cultivated three Roseobacter species, Roseobacter denitrificans, Oceanobulbus indolifexand Dinoroseobacter shibae. For each species we measured chloramphenicol sensitivity, viability over 11 weeks of glycerol-based cryopreservation and tested the effectiveness of a series of electroporation and heat shock protocols for transformation using a variety of plasmid types. We also attempted construction of an incubator-shaker device using only publicly available components. Finally, a subgroup comprising citizen scientists designed and attempted a procedure for isolating the cold resistance anf1 gene from Oceanobulbus indolifexcells and subcloning it into a BioBrick(TM) formatted plasmid. Results. All species were stable

  2. Variations in Microbial Community Structure through the Stratified Water Column in the Tyrrhenian Sea (Central Mediterranean

    Directory of Open Access Journals (Sweden)

    Francesco Smedile

    2015-08-01

    Full Text Available The central Mediterranean Sea is among the most oligotrophic habitats in the marine environment. In this study, we investigated the abundance, diversity and activity of prokaryoplankton in the water column (25–3000-m depth at Station Vector (Tyrrhenian Sea, 39°32.050′ N; 13°22.280′ E. This specific water column consists of three different water masses (Modified Atlantic Water (MAW, Levantine Intermediate Water (LIW and Tyrrhenian Deep Water (TDW, possessing a typical stratification of the Central Mediterranean basin. CARD-FISH showed that the metabolically-active fraction of bacterial populations exceeded the archaeal fraction along the whole water column, except at the deepest water masses. 16S rDNA and 16S rRNA clone libraries obtained from each type of water mass were used to analyse the prokaryoplankton community structure and to distinguish between active and “less active” microbial fractions. Our results showed that the rRNA-derived bacterial libraries seemed to be more depth specific compared to 16S rDNA-derived counterparts. Major differences were detected between the active fractions of bacterioplankton thriving in photic (25 m, MAW and aphotic layers (500–3000 m, LIW and TDW respectively, whereas no statistically-significant differences were detected within the deep, aphotic layers (500–3000 m, LIW and TDW. Archaeal communities possessed more depth-specific distribution patterns with both total and active fractions showing depth stratification. Cyanobacteria and Marine Group II MAGII of Euryarchaea dominated the MAW prokaryoplankton. A notable fraction of Geitlerinema-related cyanobacteria was detected among the metabolically-active bacterial population recovered from the mesopelagic (500 m, LIW aphotic layer, which is indicative of their mixotrophic behaviour. Heterotrophic Gammaproteobacteria and members of Marine Group 1.1a and the PSL12-related ALOHA group of Thaumarchaeota were both abundant in the aphotic layers

  3. Effect of permafrost thawing on organic carbon and trace element colloidal speciation in the thermokarst lakes of western Siberia

    Directory of Open Access Journals (Sweden)

    O. S. Pokrovsky

    2011-03-01

    Full Text Available To examine the mechanisms of carbon mobilization and biodegradation during permafrost thawing and to establish a link between organic carbon (OC and other chemical and microbiological parameters in forming thermokarst (thaw lakes, we studied the biogeochemistry of OC and trace elements (TEs in a chronosequence of small lakes that are being formed due to permafrost thawing in the northern part of western Siberia. Twenty lakes and small ponds of various sizes and ages were sampled for dissolved and colloidal organic carbon, metals and culturable heterotrophic bacterial cell number. We observed a sequence of ecosystems from peat thawing and palsa degradation due to permafrost subsidence in small ponds to large, km-size lakes that are subject to drainage to, finally, the khasyrey (drained lake formation. There is a systematic evolution of both total dissolved and colloidal concentration of OC and TEs in the lake water along with the chronosequence of lake development that may be directly linked to the microbial mineralization of dissolved organic matter and the liberation of the inorganic components (Fe, Al, and TEs from the organo-mineral colloids.

    In this chronosequence of lake development, we observed an apparent decrease in the relative proportion of low molecular weight <1 kDa (1 kDa ~ 1 nm OC concentration along with a decrease in the concentration of total dissolved (<0.45 μm OC. This decrease was accompanied by an increase in the small size organic ligands (probably autochthonous exometabolites produced by the phytoplankton and a simultaneous decrease in the proportion of large-size organic (humic complexes of allochthonous (soil origin. This evolution may be due to the activity of heterotrophic bacterioplankton that use allochthonous organic matter and dissolved nutrients originating from peat lixiviation. Most insoluble TEs demonstrate a systematic decrease in concentration during filtration (5 μm, 0.45 μm exhibiting a similar

  4. Biodegradability of terrigenous dissolved organic matter in estuaries draining glacial and wetland-dominated watersheds

    Science.gov (United States)

    Fellman, J. B.; Hood, E.; Spencer, R. G.; Edwards, R. T.; D'Amore, D. V.; Hernes, P. J.

    2008-12-01

    of tryptophan-like fluorescence increased with increasing salinity and is likely associated with an increase in bacterioplankton and/or phytoplankton growth. Taken together, our findings suggest that terrigenous DOM could be an important source of C, N and energy to riverine and near-shore coastal food webs. These findings are particularly important in estuaries draining glacial watersheds, due to the potential for future reductions in glacial coverage and subsequent changes in riverine export of labile DOM and nutrients.

  5. Importance of planktonic community respiration on the carbon balance of the East China Sea in summer

    Science.gov (United States)

    Chen, Chung-Chi; Chiang, Kuo-Ping; Gong, Gwo-Ching; Shiah, Fuh-Kwo; Tseng, Chun-Mao; Liu, Kon-Kee

    2006-12-01

    The East China Sea (ECS) is one of the largest continental shelves in the world; however, the role that biota plays in the carbon fluxes of this shelf ecosystem is still obscure. To evaluate the organic carbon balance and the roles played by planktonic communities in organic carbon consumption, two cruises with stations covering almost the entire shelf were conducted during the high productivity and high river flow season of the ECS in June (the early summer) and August (the middle summer) 2003. Results showed that biological activity was significantly higher in the early summer. To flourish in the early summer, plankton need a significant fluvial input of dissolved inorganic nutrients and organic matter from the Chinese coast, especially from the Changjiang (aka Yangtze River), might be one of the main driving forces. Further analysis showed that most planktonic community respiration (PCR) could be attributed to phytoplankton and bacterioplankton, which accounted for over 96% of the total planktonic biomass (in carbon units) in summer. This might partially explain why mean PCR was higher in June (˜114 mg C m-3 d-1), with higher phytoplankton biomass, than in August (˜40 mg m-3 d-1). The ratio of integrated primary production to PCR (i.e., the P/R ratio) was, however, less than 1, with a mean ± SD value of 0.35 ± 0.41 for all the pooled data. This indicates a significant amount of organic carbon has been regenerated through planktonic activity in the water column. The sea-air difference in fCO2, however, changed from a mean value of -64.5 ± 61.3 ppm in June to 10.0 ± 37.5 ppm in August. To explain the contradictory results between PCR and fCO2, we suggest that the dissolved inorganic carbon regenerated through planktonic respiration could be stored in the subsurface layer and may affect the fCO2 in the surface water, which is what controls the shelf sea either as an atmospheric CO2 sink or as a source, depending on the prevailing physical forces. These

  6. Biogeochemical and ecological functioning of the low-salinity water lenses in the region of the Rhone River freshwater influence, NW Mediterranean Sea

    Science.gov (United States)

    Diaz, Frédéric; Naudin, Jean-Jacques; Courties, Claude; Rimmelin, Peggy; Oriol, Louise

    2008-07-01

    A quasi-synoptic survey of a eulerian small grid was carried out twice during mid-spring 2002 in the Gulf of Lions, NW Mediterranean Sea. Analysis of hydrological core parameters reveal for the first time, in the region of freshwater influence (ROFI) of the Rhone River, the presence of low-salinity water (LSW) lenses. The present work details the biogeochemical and ecological functioning of the two LSW lenses from a combined analysis of nutrients and organic matter content, taxonomic assemblages of phytoplankton, primary productivity measurements and nitrogen regeneration fluxes. During the first survey, the lens observed is only detached in part from the Rhone River plume and is considered as a juvenile lens. In contrast, the second lens is totally detached from the plume forming a confined 3D structure with a large vertical development and is considered as having a more advanced maturity. A second survey, 4 days later, provided the opportunity to propose a complete sequence of ecological functioning of the LSW lenses, from their formation to a late stage of maturity just before dispersion. Nitrate contents and dissolved organic matter remain in high concentrations during the juvenile stages while the little available phosphate is rapidly exhausted. In such, an unbalanced-nutrient environment picoplankton appear to out-compete bacterioplankton for phosphate and other resources such as ammonium. In turn, the dominance of such prokaryotic assemblages could have involved the rapid development of microzooplankton. The sudden increase in phosphate observed in a more advanced stage of lens maturity is attributed to intense P-regeneration driven by the large abundance of microzooplankton. This top-down control does not seem to enable the prokaryotic assemblages to bloom again but the high concentrations of phosphate and nitrate favour the development of larger phytoplankton. These autotrophic communities rapidly exhaust nutrients and then decline in the confined

  7. Bacterial abundance, activity, and viability in the eutrophic River Warnow, northeast Germany.

    Science.gov (United States)

    Freese, H M; Karsten, U; Schumann, R

    2006-01-01

    states of viable and active cells in natural bacterioplankton communities. However, it remains unclear why fractions of viable and active cells were rather low in this eutrophic river in comparison to similar waters. We recommend to carefully address cells as viable in contrast to nonviable, i.e., dead. As viable cells may be active or inactive with respect to many different activities, e.g., substrate uptake, respiration, hydrolysis, and cell deviation, it is necessary to choose the method to visualize active cells according to the question to be answered. PMID:16395540

  8. Biogeochemical Composition of Mediterranean Waters Outside Thau Lagoon

    Science.gov (United States)

    Souchu, P.; Gasc, A.; Cahet, G.; Vaquer, A.; Collos, Y.; Deslous-Paoli, J. M.

    1997-03-01

    Physicochemical characteristics (temperature, salinity, dissolved oxygen), nutrients (NO 3-, NO 2-, NH 4+, soluble reactive phosphorus, Si), dissolved organic matter with bacterial cell counts (DON, DOP, DOC, BACT) and particulate matter (POC, PON, Chl a) were measured weekly from January 1993 to March 1994 in Mediterranean surface waters, sampled 2·5 km offshore in Thau Lagoon (Sète, France). Waters outside the lagoon displayed salinity reductions below 29 which corresponded to flood periods of the Rhône River and/or to winds oriented in a southeasterly direction. Levels of nutrients were increased by the influence of the Rhône river plume. Concentrations of NO 3-and NH 4+were rather close to the theoretical dilution line, while SRP and Si seemed to be rapidly taken up along their dilution gradient, especially in spring. The influx of NO 3-enriched waters into the lagoon in October showed that the Rhône river plume can potentially fertilize this lagoon. The flux of nutrient from the Rhône River led to Chl amaxima above 4 μ g l -1in spring. The concentration of DOC and BACT reached peak values at the decay of the spring bloom and decreased to their lowest level afterwards, suggesting that primary production was an important source of DOC but also that DOC was repackaged in the microbial loop rather than being transported to deeper layers. Yearly averaged atomic C:N and C:P ratios in DOM were 15 and 1000, respectively, which probably compelled bacterioplankton to compete with phytoplankton for NH 4+and SRP. No influence of the Rhône River was observed during summer. This period was characterized by SRP, NO 3-and NO 2-concentrations below the limits of detection and by the lowest levels in DOC, DON, BACT and Chl a. However, NH 4+and DOP concentrations remained, respectively, above 0·3 and 0·15 μ M, and the summer period corresponded to oxygen supersaturation (up to 122%). These observations suggest the dominance of picophytoplanktonic communities with low

  9. Phytoplankton diversity and productivity in a highly turbid, tropical coastal system (Bach Dang Estuary, Vietnam

    Directory of Open Access Journals (Sweden)

    E. J. Rochelle-Newall

    2011-01-01

    Full Text Available The factors controlling estuarine phytoplankton diversity and production are relatively well known in temperate systems. Less however is known about the factors affecting phytoplankton community distribution in tropical estuaries. This is surprising given the economic and ecological importance of these large, deltaic ecosystems, such as are found in South East Asia. Here we present the results from an investigation into the factors controlling phytoplankton distribution and phytoplankton-bacterial coupling in the Bach Dang Estuary, a sub-estuary of the Red River system, in Northern Vietnam. Phytoplankton diversity and primary and bacterial production, nutrients and metallic contaminants (mercury and organotin were measured during two seasons: wet (July 2008 and dry (March 2009. Phytoplankton community composition differed between the two seasons with only a 2% similarity between July and March. The large spatial extent and complexity of defining the freshwater sources meant that simple mixing diagrams could not be used in this system. We therefore employed multivariate analyses to determine the factors influencing phytoplankton community structure. Salinity and suspended particulate matter were important factors in determining phytoplankton distribution, particularly during the wet season. We also show that phytoplankton community structure is probably influenced by the concentrations of mercury species (inorganic mercury and methyl mercury in both the particulate and dissolved phases and of tri-, di, and mono-butyl tin species found in this system. Freshwater phytoplankton community composition was associated with dissolved methyl mercury and particulate inorganic mercury concentrations during the wet season, whereas, during the dry season, dissolved methyl mercury and particulate butyl tin species were important factors for the discrimination of the phytoplankton community structure. Phytoplankton-bacterioplankton coupling was also

  10. Spatially explicit individual-based modeling using a fixed super-individual density

    Science.gov (United States)

    Hellweger, Ferdi L.

    2008-02-01

    Individual-based models (IBMs) of planktonic microorganisms (e.g., bacterioplankton, phytoplankton) have to simulate large numbers of individuals. Because of computational limitations these models rely on simulating a number of super-individuals that are representative of a larger number of individuals. Using a fixed representative number (the number of individuals one super-individual represents) results in a lower computational resolution (number of super-individuals) at times and in areas of low individual densities, which is undesirable when (a) large temporal and/or spatial gradients exist and (b) variability in state variables or behavior at low densities is important. Various methods exist that fix the number of super-individuals in the global model domain by allowing the representative number to vary in time. Those methods solve the problem introduced by large temporal gradients, but do not address spatial gradients. This paper presents an accounting method that maintains an approximately constant super-individual density in time and space. Each spatial model segment has a local super-individual population that is resampled when the number shrinks or grows outside user-specified bounds, or when the variance of the representative numbers exceeds a user-specified threshold. This local method is compared to a global method and evaluated quantitatively against the analytical solution to an instantaneous input (slug release) into a river, and qualitatively in a biogeochemical phytoplankton model applied to a point source nutrient discharge into a river. Computations are performed using the iAlgae individual-based phytoplankton modeling framework. The applications demonstrate that the local method results in a spatially uniform or density-independent relative error, and it is computationally more efficient at controlling relative error at low densities. However, for the same total number of super-individuals, it is computationally more demanding and therefore

  11. Covariation of viral parameters with bacterial assemblage richness and diversity in the water column and sediments

    Science.gov (United States)

    Hewson, Ian; Fuhrman, Jed A.

    2007-05-01

    include many opportunistic taxa (e.g. Vibrionaceae), and because these bacteria may be more susceptible to viral attack due to enhanced resource uptake abilities and potentially rapid localized growth, it is possible that this negative effect was due to enhanced viral lysis. Consequently, virus infection may have positive effects upon bacterioplankton diversity in the oligotrophic ocean, by regulating the abundance of dominant competitors, and allowing rarer taxa to coexist; however, some rarer taxa (such as diazotrophs) may be more susceptible to viral attack due to opportunistic lifestyles.

  12. Phosphorus speciation and transformation along transects in the Benguela upwelling region

    Science.gov (United States)

    Nausch, Monika; Nausch, Günther

    2014-11-01

    Transformation of phosphate (PO4) introduced by upwelling into the 20 m surface layer was studied four times in turn along a transect perpendicular to the coast of Namibia from August 27th to September 15th 2011. [33P]PO4 uptake rates as well as the concentrations of inorganic nutrients (PO4, NO2/3), dissolved and particulate organic phosphorus, and particulate organic carbon and nitrogen were measured and the respective stoichiometry was determined. The fate and interactions of these components are described in relation to both the distance from the coast and a calculated "pseudoage" of the water masses to get knowledge about the phosphorus dynamics during surface transport and aging of upwelled water. PO4 decreased from 1.6 μM in the upwelling cell near the coast to 0.4 μM at remote stations. The decrease in PO4 was lower than that of nitrate, resulting in a lower N:P ratio seawards (from 12-16 to 5-9). PO4 depletion was reflected only partially in increasing DOP, but not in POP concentrations. Concentrations of POP, POC and PON decreased with the distance from the coast and with "pseudoage", indicating that produced particulate matter is removed from the upper 20 m layer. A mean PO4 turnover time of 57 days, based on [33P]PO4 uptake measurements, suggested complete PO4 consumption within the transects and thus the need for an additional PO4 supply to sustain the gradient. Fast mineralisation of DOP could be one mechanism. Deduced from our bioassays, PO4 seemed to be transformed into DOP by heterotrophic bacteria which was mineralized back to PO4 within few days. Hence, our results support the hypothesis that the observed PO4 gradient in the 20 m surface layer is not only due to input in the upwelling center and locomotion to the open ocean by Ekman transport combined with utilization by phyto- and bacterioplankton. PO4 has to be provided by remineralisation and input from deeper layers probably by wind curl driven mixing processes. However, most of the

  13. Viral abundance, production, decay rates and life strategies (lysogeny versus lysis) in Lake Bourget (France).

    Science.gov (United States)

    Thomas, Rozenn; Berdjeb, Lyria; Sime-Ngando, Télesphore; Jacquet, Stéphan

    2011-03-01

    . The calculated release of carbon and phosphorus from viral lysis reached up to 56.5 µgC l⁻¹ day⁻¹ (assuming 20 fgC cell⁻¹) and 1.4 µgP l⁻¹ day⁻¹ (assuming 0.5 fgP cell⁻¹), respectively, which may represent a significant fraction of bacterioplankton nutrient demand. This study provides new evidence of the quantitative and functional importance of the virioplankton in the functioning of microbial food webs in peri-alpine lakes. It also highlights methodologically dependent results. PMID:21054737

  14. Production of dissolved organic carbon by Arctic plankton communities: Responses to elevated carbon dioxide and the availability of light and nutrients

    Science.gov (United States)

    Poulton, Alex J.; Daniels, Chris J.; Esposito, Mario; Humphreys, Matthew P.; Mitchell, Elaine; Ribas-Ribas, Mariana; Russell, Benjamin C.; Stinchcombe, Mark C.; Tynan, Eithne; Richier, Sophie

    2016-05-01

    The extracellular release of dissolved organic carbon (DOC) by phytoplankton is a potentially important source of labile organic carbon for bacterioplankton in pelagic ecosystems. In the context of increasing seawater partial pressure of CO2 (pCO2), via the oceanic absorption of elevated atmospheric CO2 (ocean acidification), several previous studies have reported increases to the relative amount of carbon fixed into particulates, via primary production (PP), and dissolved phases (DOC). During the summer of 2012 we measured DOC production by phytoplankton communities in the Nordic seas of the Arctic Ocean (Greenland, Norwegian and Barents Sea) from both in situ sampling and during three bioassay experiments where pCO2 levels (targets ~550 μatm, ~750 μatm, ~1000 μatm) were elevated relative to ambient conditions. Measurements of DOC production and PP came from 24 h incubations and therefore represent net DOC production rates, where an unknown portion of the DOC released has potentially been utilised by heterotrophic organisms. Production of DOC (net pDOC) by in situ communities varied from 0.09 to 0.64 mmol C m-3 d-1 (average 0.25 mmol C m-3 d-1), with comparative rates in two of the experimental bioassays (0.04-1.23 mmol C m-3 d-1) and increasing dramatically in the third (up to 5.88 mmol C m-3 d-1). When expressed as a fraction of total carbon fixation (i.e., PP plus pDOC), percentage extracellular release (PER) was 14% on average (range 2-46%) for in situ measurements, with PER in the three bioassays having a very similar range (2-50%). A marked increase in pDOC (and PER) was only observed in one of the bioassays where nutrient levels (nitrate, silicic acid) dropped dramatically relative to starting (ambient) concentrations; no pCO2 treatment effect on pDOC (or PER) was evident across the three experiments. Examination of in situ net pDOC (and PER) found significant correlations with decreasing silicic acid and increasing euphotic zone depth, indicating that

  15. Factors shaping bacterial phylogenetic and functional diversity in coastal waters of the NW Mediterranean Sea

    Science.gov (United States)

    Boras, Julia A.; Vaqué, Dolors; Maynou, Francesc; Sà, Elisabet L.; Weinbauer, Markus G.; Sala, Maria Montserrat

    2015-03-01

    To evaluate the main factors shaping bacterioplankton phylogenetic and functional diversity in marine coastal waters, we carried out a two-year study based on a monthly sampling in Blanes Bay (NW Mediterranean). We expected the key factors driving bacterial diversity to be (1) temperature and nutrient concentration, together with chlorophyll a concentration as an indicator of phytoplankton biomass and, hence, a carbon source for bacteria (here called bottom-up factors), and (2) top-down pressure (virus- and protist-mediated mortality of bacteria). Phylogenetic diversity was analyzed by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA. Functional diversity was assessed by using monomeric carbon sources in Biolog EcoPlates and by determining the activity of six extracellular enzymes. Our results indicate that the bacterial phylogenetic and functional diversity in this coastal system is shaped mainly by bottom-up factors. A dendrogram analysis of the DGGE banding patterns revealed three main sample clusters. Two clusters differed significantly in temperature, nitrate and chlorophyll a concentration, and the third was characterized by the highest losses of bacterial production due to viral lysis detected over the whole study period. Protistan grazing had no effect on bacterial functional diversity, since there were no correlations between protist-mediated mortality (PMM) and extracellular enzyme activities, and utilization of only two out of the 31 carbon sources (N-acetyl-D-glucosamine and α-cyclodextrin) was correlated with PMM. In contrast, virus-mediated mortality correlated with changes in the percentage of use of four carbon sources, and also with specific leu-aminopeptidase and β-glucosidase activity. This suggests that viral lysate provides a pool of labile carbon sources, presumably including amino acids and glucose, which may inhibit proteolytic and glucosidic activity. Our results indicate that bottom-up factors play a more important role than

  16. [Causes of jellyfish blooms and their influence on marine environment].

    Science.gov (United States)

    Qu, Chang-feng; Song, Jin-ming; Li, Ning

    2014-12-01

    and finally made the ambient water become acidic and hypoxic. The pH decreased by 1.3, while the mean dissolved oxygen demand reached 32.8 micromol x kg(-1) x h(-1). Jellyfish blooms also influenced the marine organism community, which might reduce the biomass of some fish and zooplankton, increase the amount of bacterioplankton, indirectly .increase the quantity of phytoplankton and lead to abnormal primary production. PMID:25876425

  17. Enhanced recycling of organic matter and Os-isotopic evidence for multiple magmatic or meteoritic inputs to the Late Permian Panthalassic Ocean, Opal Creek, Canada

    Science.gov (United States)

    Georgiev, Svetoslav V.; Stein, Holly J.; Hannah, Judith L.; Henderson, Charles M.; Algeo, Thomas J.

    2015-02-01

    The geochemical record for the Permian-Triassic boundary in northern latitudes is essential to evaluation of global changes associated with the most profound extinction of life on Earth. We present inorganic and organic geochemical data, and Re-Os isotope systematics in a critical stratigraphic interval of pre- and post-extinction Upper Permian-Lower Triassic sediments from Opal Creek, western Canada (paleolatitude of ∼30°N). We document significant and long-lived changes in Panthalassa seawater chemistry that were initiated during the first of four magmatic or meteoritic inputs to Late Permian seawater, evidenced by notable decreases of Os isotopic ratios upsection. Geochemical signals indicate establishment of anoxic bottom waters shortly after regional transgression reinitiated sedimentation in the Late Permian. Euxinic signals are most prominent in the Upper Permian sediments with low organic carbon and high sulfur contents, and gradually wane in the Lower Triassic. The observed features may have been generated in a strongly euxinic ocean in which high bacterioplankton productivity sustained prolific microbial sulfate reduction in the sediment and/or water column, providing hydrogen sulfide to form pyrite. This scenario requires nearly complete anaerobic decomposition of predominantly labile marine organic matter (OM) without the necessity for a complete collapse of primary marine productivity. Similar geochemical variations could have been achieved by widespread oxidation of methane by sulfate reducers after a methanogenic burst in the Late Permian. Both scenarios could have provided similar kill mechanisms for the latest Permian mass extinction. Despite the moderate thermal maturity of the section, OM in all studied samples is dominantly terrestrial and/or continentally derived, recycled and refractory ancient OM. We argue that, as such, the quantity of the OM in the section mainly reflects changes in terrestrial vegetation and/or weathering, and not in

  18. Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    C. Jeanthon

    2011-05-01

    Full Text Available Aerobic anoxygenic phototrophic (AAP bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a, the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 52 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94% was affiliated with the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the

  19. Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    C. Jeanthon

    2011-07-01

    Full Text Available Aerobic anoxygenic phototrophic (AAP bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a, the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 54 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94 % was affiliated to the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the discrepancies

  20. Application of flow cytometry to enumerate small plankton%利用流式细胞仪计数微型浮游生物的方法∗

    Institute of Scientific and Technical Information of China (English)

    李胜男; 王秀娟; 周建; 孔繁翔; 史小丽

    2015-01-01

    . While for the heterotrophic bacteria, protozoan and viruses, a combination of exogenous fluorochromes staining on cell components( mainly nucleic acids) is required to better characterize different cell groups. Now flow cytometry has become a routine methodology for detecting density of the autotrophic phytoplankton and heterotrophic bacterioplankton. However, it has been only used in quantification of protozoan and viruses in the recent 10 years, for those applications which are much more difficult and complicated for the larger cell size and less abundant den-sities of protozoan and much smaller cell size( even smaller than the wavelength of the laser light used) of viruses compared to bac-terioplankton and small phytoplankton. The different principles and protocols used to discriminate autotrophic phytoplankton, het-erotrophic bacteria, protozoan and viruses through flow cytometry were reviewed in detail, and future applications of flow cytometry in aquatic microbiology were also prospected.

  1. Arctic sea-ice melting: Effects on hydroclimatic variability and on UV-induced carbon cycling

    Science.gov (United States)

    Sulzberger, Barbara

    2016-04-01

    Since 1980 both the perennial and the multiyear central Arctic sea ice areas have declined by approximately 13 and 15% per decade, respectively (IPCC, 2013). Arctic sea-ice melting has led to an increase in the amplitude of the Northern Hemisphere jet stream and, as a consequence, in more slowly moving Rossby waves which results in blocking of weather patterns such as heat waves, droughts, cold spells, and heavy precipitation events (Francis and Vavrus, 2012). Changing Rossby waves account for more than 30% of the precipitation variability over several regions of the northern middle and high latitudes, including the US northern Great Plains and parts of Canada, Europe, and Russia (Schubert et al., 2011). From 2007 to 2013, northern Europe experienced heavy summer precipitation events that were unprecedented in over a century, concomitant with Arctic sea ice loss (Screen, 2013). Heavy precipitation events tend to increase the runoff intensity of terrigenous dissolved organic matter (tDOM) (Haaland et al., 2010). In surface waters tDOM is subject to UV-induced oxidation to produce atmospheric CO2. Mineralization of DOM also occurs via microbial respiration. However, not all chemical forms of DOM are available to bacterioplankton. UV-induced transformations generally increase the bioavailability of tDOM (Sulzberger and Durisch-Kaiser, 2009). Mineralization of tDOM is an important source of atmospheric CO2 and this process is likely to contribute to positive feedbacks on global warming (Erickson et al., 2015). However, the magnitudes of these potential feedbacks remain unexplored. This paper will discuss the following items: 1.) Links between Arctic sea-ice melting, heavy precipitation events, and enhanced tDOM runoff. 2.) UV-induced increase in the bioavailability of tDOM. 3.) UV-mediated feedbacks on global warming. References Erickson, D. J. III, B. Sulzberger, R. G. Zepp, A. T. Austin (2015), Effects of stratospheric ozone depletion, solar UV radiation, and climate

  2. Characterization of biocenosis in the storage-reservoirs of liquid radioactive wastes of 'Mayak' PA

    International Nuclear Information System (INIS)

    A number of storage-reservoirs of liquid radioactive wastes of 'Mayak' Production Association ('Mayak' PA) with different levels of radioactive contamination: reservoir R-17 ('Staroye Boloto'), reservoir R-9 (Lake Karachay), reservoirs of the Techa Cascade R-3 (Koksharov pond), R-4 (Metlinsky pond), R-10 and R-11 is located in Chelyabinsk Oblast (Russia). The operation of these reservoirs began in 1949-1964. Full-scale hydro-biological studies of these reservoirs were started in 2007. The research into the status of biocenosis of these storage reservoirs of liquid radioactive wastes of 'Mayak' PA was performed in 2007 - 2011. The status of biocenosis was evaluated in accordance with the status of following communities: bacterio-plankton, phytoplankton, zooplankton, zoo-benthos, macrophytes and ichthyofauna. The status of ecosystems was determined by radioactive and chemical contamination of water bodies. The results of hydro-biological investigations showed that no changes in the status of biota in reservoir R-11 were revealed as compared to the biological parameters of the water bodies of this geographical zone. In terms of biological parameters the status of the ecosystem of the reservoir R-11 is characterized by a sufficient biological diversity, and can be considered acceptable. The ecosystem of the reservoir R-10 maintains its functional integrity, although there were registered negative effects in the zoo-benthos community associated with the decrease in the parameters of the development of pelophylic mollusks that live at the bottom of the water body throughout the entire life cycle. In reservoir R-4 the parameters of the development of phytoplankton did not differ from those in Reservoirs R-11 and R-10; however, a significant reduction in the quantity of Cladocera and Copepoda was registered in the zooplankton community, while in the zoo-benthos there were no small mollusks that live aground throughout the entire life cycle. In reservoir R-3 there was no

  3. MOLECULAR APPROACHES FOR IN SITU IDENTIFCIATION OF NITRATE UTILIZATION BY MARINE BACTERIA AND PHYTOPLANKTON

    Energy Technology Data Exchange (ETDEWEB)

    Frischer, Marc E. [Skidaway Institute of Oceanography; Verity, Peter G.; Gilligan, Mathew R.; Bronk, Deborah A.; Zehr, Jonathan P.; Booth, Melissa G.

    2013-09-12

    Traditionally, the importance of inorganic nitrogen (N) for the nutrition and growth of marine phytoplankton has been recognized, while inorganic N utilization by bacteria has received less attention. Likewise, organic N has been thought to be important for heterotrophic organisms but not for phytoplankton. However, accumulating evidence suggests that bacteria compete with phytoplankton for nitrate (NO3-) and other N species. The consequences of this competition may have a profound effect on the flux of N, and therefore carbon (C), in ocean margins. Because it has been difficult to differentiate between N uptake by heterotrophic bacterioplankton versus autotrophic phytoplankton, the processes that control N utilization, and the consequences of these competitive interactions, have traditionally been difficult to study. Significant bacterial utilization of DIN may have a profound effect on the flux of N and C in the water column because sinks for dissolved N that do not incorporate inorganic C represent mechanisms that reduce the atmospheric CO2 drawdown via the ?biological pump? and limit the flux of POC from the euphotic zone. This project was active over the period of 1998-2007 with support from the DOE Biotechnology Investigations ? Ocean Margins Program (BI-OMP). Over this period we developed a tool kit of molecular methods (PCR, RT-PCR, Q-PCR, QRT-PCR, and TRFLP) and combined isotope mass spectrometry and flow-cytometric approaches that allow selective isolation, characterization, and study of the diversity and genetic expression (mRNA) of the structural gene responsible for the assimilation of NO3- by heterotrophic bacteria (nasA). As a result of these studies we discovered that bacteria capable of assimilating NO3- are ubiquitous in marine waters, that the nasA gene is expressed in these environments, that heterotrophic bacteria can account for a significant fraction of total DIN uptake in different ocean margin systems, that the expression of nasA is

  4. Characterization of biocenosis in the storage-reservoirs of liquid radioactive wastes of 'Mayak' PA

    Energy Technology Data Exchange (ETDEWEB)

    Pryakhin, E.; Tryapitsina, G.; Andreyev, S.; Akleyev, A. [Urals Research Center for Radiation Medicine - URCRM (Russian Federation); Mokrov, Y.; Ivanov, I. [Mayak PA (Russian Federation)

    2014-07-01

    A number of storage-reservoirs of liquid radioactive wastes of 'Mayak' Production Association ('Mayak' PA) with different levels of radioactive contamination: reservoir R-17 ('Staroye Boloto'), reservoir R-9 (Lake Karachay), reservoirs of the Techa Cascade R-3 (Koksharov pond), R-4 (Metlinsky pond), R-10 and R-11 is located in Chelyabinsk Oblast (Russia). The operation of these reservoirs began in 1949-1964. Full-scale hydro-biological studies of these reservoirs were started in 2007. The research into the status of biocenosis of these storage reservoirs of liquid radioactive wastes of 'Mayak' PA was performed in 2007 - 2011. The status of biocenosis was evaluated in accordance with the status of following communities: bacterio-plankton, phytoplankton, zooplankton, zoo-benthos, macrophytes and ichthyofauna. The status of ecosystems was determined by radioactive and chemical contamination of water bodies. The results of hydro-biological investigations showed that no changes in the status of biota in reservoir R-11 were revealed as compared to the biological parameters of the water bodies of this geographical zone. In terms of biological parameters the status of the ecosystem of the reservoir R-11 is characterized by a sufficient biological diversity, and can be considered acceptable. The ecosystem of the reservoir R-10 maintains its functional integrity, although there were registered negative effects in the zoo-benthos community associated with the decrease in the parameters of the development of pelophylic mollusks that live at the bottom of the water body throughout the entire life cycle. In reservoir R-4 the parameters of the development of phytoplankton did not differ from those in Reservoirs R-11 and R-10; however, a significant reduction in the quantity of Cladocera and Copepoda was registered in the zooplankton community, while in the zoo-benthos there were no small mollusks that live aground throughout the entire life

  5. Structural Dynamics of Community Gene Expression In a Freshwater Cyanobacterial Bloom Over a Day-Night Cycle

    Science.gov (United States)

    Wang, J.; Fernando, S.; Thompson, J. R.

    2011-12-01

    Cyanobacterial blooms are a major problem in eutrophic lakes and reservoirs, negatively impacting the ecology of the water body through oxygen depletion upon bloom decay and in some cases through production of toxins. Waterborne cyanobacterial toxins pose a public health threat through drinking and recreational exposure. The frequency of harmful cyanobacterial blooms (cyanoHABs) is predicted to increase due to warming regional climates (Paerl et.al, 2011) and increases in non-point source pollution due to urban expansion (Novotny, 2011). CyanoHABs represent complex consortia of cyanobacteria that live in association with diverse assemblages of heterotrophic and anoxygenic photosynthetic bacteria. A better understanding of the structure, function, and interaction between members of the complex microbial communities that support the proliferation of toxigenic cyanobacteria will improve our ability to prevent and control cyanoHABs. Studies of community gene expression, or metatranscriptomics, provide a powerful approach for quantifying changes in both the taxonomic composition (structure) and activity (function) of complex microbial systems in response to dynamic environmental conditions. We have used next-generation Illumina sequencing to characterize the metatranscriptome of a tropical eutrophic drinking water reservoir dominated by the toxigenic cyanobacterium Microcystis aeruginosa over a day/night cycle. Bacterioplankton sampling was carried out at six time points over a 24 hour period to capture variability associated with changes in the balance between phototrophic and heterotrophic activity. Total RNA was extracted and subjected to ribosomal depletion followed by cDNA synthesis and sequencing, generating 493,468 to 678,064 95-101 bp post-quality control reads per sample. Hierarchical Clustering of transcriptional profiles supported sorting of samples into two clusters corresponding to "day" and "night" collection times. Annotation of reads through the MG

  6. Biogeography, Cultivation and Genomic Characterization of Prochlorococcus in the Red Sea

    KAUST Repository

    Shibl, Ahmed A.

    2015-12-16

    Aquatic primary productivity mainly depends on pelagic phytoplankton. The globally abundant marine picocyanobacteria Prochlorococcus comprises a significant fraction of the photosynthetic biomass in most tropical, oligotrophic oceans. The Red Sea is an enclosed narrow body of water characterized by continuous solar irradiance, and negligible annual rainfall, in addition to elevated temperatures and salinity levels, which mimics a global warming scenario. Analysis of 16S rRNA sequences of bacterioplankton communities indicated the predominance of a high-light adapted ecotype (HL II) of Prochlorococcus at the surface of the Northern and Central Red Sea. To this end, we analyzed the distribution of Prochlorococcus at multiple depths within and below the euphotic zone in different regions of the Red Sea, using clone libraries of the 16S–23S rRNA internal transcribed spacer (ITS) region. Results indicated a high diversity of Prochlorococcus ecotypes at the 100 m depth in the water column and an unusual dominance of HL II-related sequences in deeper waters of the Red Sea. To further investigate the microdiversity of Prochlorococcus over a wider biogeographical scope, we used a 454-pyrosequencing approach to analyze rpoC1 gene pyrotags. Samples were collected from the surface of the water column to up to 500 m at 45 stations that span the Red Sea’s main basin from 4 north to south. Phylogenetic analysis of abundant rpoC1 OTUs revealed genotypes of recently discovered strains that belong to the high-light and lowlight clades. In addition, we used a rapid community-profiling tool (GraftM) and quantitatively analyzed rpoC1 gene abundance from 45 metagenomes to assess the Prochlorococcus community structure across vertical and horizontal physicochemical gradients. Results revealed the clustering of samples according to their depth and a strong influence on ecotypic distribution by temperature and oxygen levels. In efforts to better understand how the cells survive the

  7. Decrease of concentration and colloidal fraction of organic carbon and trace elements in response to the anomalously hot summer 2010 in a humic boreal lake

    Energy Technology Data Exchange (ETDEWEB)

    Shirokova, L.S. [Institute of Ecological Problems of the North, Ural Branch of Russian Academy of Science, Naberezhnaya Severnoi Dviny, 23, Arkhangelsk, 163000 (Russian Federation); GET UMR 5563 CNRS, Université de Toulouse, 14 Avenue Edouard Belin, 31400 Toulouse (France); Pokrovsky, O.S., E-mail: oleg@get.obs-mip.fr [Institute of Ecological Problems of the North, Ural Branch of Russian Academy of Science, Naberezhnaya Severnoi Dviny, 23, Arkhangelsk, 163000 (Russian Federation); GET UMR 5563 CNRS, Université de Toulouse, 14 Avenue Edouard Belin, 31400 Toulouse (France); Moreva, O.Yu.; Chupakov, A.V.; Zabelina, S.A.; Klimov, S.I.; Shorina, N.V.; Vorobieva, T.Ya. [Institute of Ecological Problems of the North, Ural Branch of Russian Academy of Science, Naberezhnaya Severnoi Dviny, 23, Arkhangelsk, 163000 (Russian Federation)

    2013-10-01

    aerobic bacterioplankton and 3) photo-degradation of DOM and photo-chemical liberation of organic-bound TE. While the first process may have caused significant decreases in the total dissolved concentration of micronutrients (a factor of 2 to 5 for Cr, Mn, Fe, Ni, Cu, Zn and Cd and a factor of > 100 for Co), the second and third factors could have brought about the decrease of allochthonous DOC concentration as well as the concentration and proportion of organic and organo-mineral colloidal forms of non-essential low-soluble trace elements present in the form of organic colloids (Al, Y, Ti, Zr, Hf, Th, Pb, all REEs). It can be hypothesized that climate warming in high latitudes capable of significantly raising surface water temperatures will produce a decrease in the colloidal fraction of most trace elements and, as a result, an increase in the most labile low molecular weight LMW{sub <1} {sub kDa} fraction. - Graphical abstract: During anomalously hot summer (August 2010), significant decrease of the proportion of colloidal organic carbon occurred in a humic boreal lake. Highlights: • Anomalous hot summer 2010 changed boreal lake biogeochemistry • Carbon and trace element concentration in the epilimnion decreased by a factor of 1.3 to 6. • Colloidal fractions of carbon and metals decreased by a factor of 1.5 to 3. • Climate warming in boreal lakes may increase the metal and carbon bioavailability.

  8. Post-glacial, land rise-induced formation and development of lakes in the Forsmark area, central Sweden

    International Nuclear Information System (INIS)

    This report describes the lakes of Uppsala county, with special emphasis on the coastal lakes in the Forsmark area. The aim of the study is to characterise different main types of lakes within the Forsmark area and to create a basis for prediction of their ontogeny, that can be used also for new lakes which due to shoreline displacement will be formed during the next 10 000 years. Areas where future research is needed to fully understand the functioning of the lake ecosystems and their ontogeny have also been identified. Three main types of lake ecosystems could be identified: The oligotrophic hardwater lakes are to a large extent surrounded by mires. Inflow as well as outflow of water is often diffuse, via the surrounding mire. The lakes are small and shallow, with nutrient poor and highly alkaline water. Three key habitats have been identified within the lakes; i) the pelagic zone, characterised by low production of biota, ii) the presumably moderately productive emergent macrophyte zone, dominated by Sphagnum and Phragmites, and iii) the light-exposed soft-bottom zone with Chara meadows and an unusually rich and presumably highly productive microbial sediment community. In later stages of the lake ontogeny, Sphagnum becomes more and more dominant in the system, which successively turns acidic. The final stage is likely to be a raised bog ecosystem with an autonomous hydrological functioning. The brown water lakes are typically found within the main part of the River Forsmarksaan and are characterised by a high flow-through of water from the upper parts of the drainage area, which are dominated by mires. Their lake water is highly stained by allochtonous organic carbon imported from the catchment area. Also in this lake type a Sphagnum-littoral successively develops, and in a mature lake three key habitats can be identified; i) the pelagic zone, most likely the dominant habitat in terms of production of organisms and in which bacterioplankton dominates the

  9. Post-glacial, land rise-induced formation and development of lakes in the Forsmark area, central Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Brunberg, Anna-Kristina; Blomqvist, Peter [Uppsala Univ. (Sweden). Dept. of Limnology, Evolutionary Biology Centre

    2000-03-15

    This report describes the lakes of Uppsala county, with special emphasis on the coastal lakes in the Forsmark area. The aim of the study is to characterise different main types of lakes within the Forsmark area and to create a basis for prediction of their ontogeny, that can be used also for new lakes which due to shoreline displacement will be formed during the next 10 000 years. Areas where future research is needed to fully understand the functioning of the lake ecosystems and their ontogeny have also been identified. Three main types of lake ecosystems could be identified: The oligotrophic hardwater lakes are to a large extent surrounded by mires. Inflow as well as outflow of water is often diffuse, via the surrounding mire. The lakes are small and shallow, with nutrient poor and highly alkaline water. Three key habitats have been identified within the lakes; i) the pelagic zone, characterised by low production of biota, ii) the presumably moderately productive emergent macrophyte zone, dominated by Sphagnum and Phragmites, and iii) the light-exposed soft-bottom zone with Chara meadows and an unusually rich and presumably highly productive microbial sediment community. In later stages of the lake ontogeny, Sphagnum becomes more and more dominant in the system, which successively turns acidic. The final stage is likely to be a raised bog ecosystem with an autonomous hydrological functioning. The brown water lakes are typically found within the main part of the River Forsmarksaan and are characterised by a high flow-through of water from the upper parts of the drainage area, which are dominated by mires. Their lake water is highly stained by allochtonous organic carbon imported from the catchment area. Also in this lake type a Sphagnum-littoral successively develops, and in a mature lake three key habitats can be identified; i) the pelagic zone, most likely the dominant habitat in terms of production of organisms and in which bacterioplankton dominates the