scholarly journals Contrasting patterns of carbon cycling and DOM processing in two phytoplankton-bacteria communities

2021 ◽  
Author(s):  
Samu Markku Elovaara ◽  
Eeva Liisa Eronen-Rasimus ◽  
Eero Jooseppi Asmala ◽  
Tobias Tamelander ◽  
Hermanni Pekka Kaartokallio
Keyword(s):  
Primary Production ◽  
Bacterial Production ◽  
Bacterial Biomass ◽  
Community Respiration ◽  
Exponential Growth Phase ◽  
Bacterial Respiration ◽  
Organic C ◽  
Optical Signals ◽  
C Cycle ◽  
Microbial Consumption

Abstract. Microbial consumption of phytoplankton-derived organic carbon in the pelagic food web is an important component of the global C cycle. We studied C cycling in two phytoplankton-bacteria systems (non-axenic cultures of a dinoflagellate Apocalathium malmogiense and a cryptophyte Rhodomonas marina) in two experiments. In the first experiment we grew phytoplankton and bacteria in nutrient replete conditions and followed C processing at early exponential growth phase and at two later phases. Primary production and total community respiration were up to 4 and 7 times higher, respectively, in the A. malmogiense treatments. Based on the optical signals, accumulating dissolved organic C (DOC) was degraded more in the R. marina treatments and the rate of bacterial production to primary production was higher. Thus, the flow of C from phytoplankton to bacteria was relatively higher in R. marina treatments than in A. malmogiense treatments which was further supported by faster 14C transfer from phytoplankton to bacterial biomass. In the second experiment we investigated consumption of the phytoplankton-derived DOC by bacteria. DOC consumption and transformation, bacterial production and bacterial respiration were all higher in R. marina treatments. In both experiments A. malmogiense supported a bacterial community predominated by bacteria specialized in the utilization of less labile DOC (class Bacteroidia) whereas R. marina supported a community predominated by copiotrophic Alpha- and Gammaproteobacteria. Our findings suggest that large dinoflagellates cycle relatively more C between phytoplankton biomass and the inorganic C pool whereas small cryptophytes direct relatively more C to the microbial loop.

scholarly journals Contrasting patterns of carbon cycling and dissolved organic matter processing in two phytoplankton–bacteria communities

2021 ◽  
Vol 18 (24) ◽  
pp. 6589-6616
Author(s):  
Samu Elovaara ◽  
Eeva Eronen-Rasimus ◽  
Eero Asmala ◽  
Tobias Tamelander ◽  
Hermanni Kaartokallio
Keyword(s):  
Primary Production ◽  
Bacterial Production ◽  
Bacterial Biomass ◽  
Community Respiration ◽  
Exponential Growth Phase ◽  
Bacterial Respiration ◽  
Organic C ◽  
Optical Signals ◽  
C Cycle ◽  
Microbial Consumption

Abstract. Microbial consumption of phytoplankton-derived organic carbon in the pelagic food web is an important component of the global C cycle. We studied C cycling in two phytoplankton–bacteria systems (non-axenic cultures of a dinoflagellate Apocalathium malmogiense and a cryptophyte Rhodomonas marina) in two complementary experiments. In the first experiment we grew phytoplankton and bacteria in nutrient-replete conditions and followed C processing at early exponential growth phase and twice later when the community had grown denser. Cell-specific primary production and total community respiration were up to 4 and 7 times higher, respectively, in the A. malmogiense treatments. Based on the optical signals, accumulating dissolved organic C (DOC) was degraded more in the R. marina treatments, and the rate of bacterial production to primary production was higher. Thus, the flow of C from phytoplankton to bacteria was relatively higher in R. marina treatments than in A. malmogiense treatments, which was further supported by faster 14C transfer from phytoplankton to bacterial biomass. In the second experiment we investigated consumption of the phytoplankton-derived DOC by bacteria. DOC consumption and transformation, bacterial production, and bacterial respiration were all higher in R. marina treatments. In both experiments A. malmogiense supported a bacterial community predominated by bacteria specialized in the utilization of less labile DOC (class Bacteroidia), whereas R. marina supported a community predominated by copiotrophic Alpha- and Gammaproteobacteria. Our findings suggest that large dinoflagellates cycle relatively more C between phytoplankton biomass and the inorganic C pool, whereas small cryptophytes direct relatively more C to the microbial loop.

scholarly journals Patterns of carbon processing at the seafloor: the role of faunal and microbial communities in moderating carbon flows

2016 ◽  
Vol 13 (15) ◽  
pp. 4343-4357 ◽  
Author(s):  
Clare Woulds ◽  
Steven Bouillon ◽  
Gregory L. Cowie ◽  
Emily Drake ◽  
Jack J. Middelburg ◽  
...  
Keyword(s):  
Bacterial Biomass ◽  
Coarse Grained ◽  
Community Respiration ◽  
Total Biomass ◽  
Coastal Zones ◽  
Organic C ◽  
Sand Flat ◽  
Permeable Sediments ◽  
C Cycling ◽  
Wide Range

Abstract. Marine sediments, particularly those located in estuarine and coastal zones, are key locations for the burial of organic carbon (C). However, organic C delivered to the sediment is subjected to a range of biological C-cycling processes, the rates and relative importance of which vary markedly between sites, and which are thus difficult to predict. In this study, stable isotope tracer experiments were used to quantify the processing of C by microbial and faunal communities in two contrasting Scottish estuarine sites: a subtidal, organic C rich site in Loch Etive with cohesive fine-grained sediment, and an intertidal, organic C poor site on an Ythan estuary sand flat with coarse-grained permeable sediments. In both experiments, sediment cores were recovered and amended with 13C labelled phytodetritus to quantify whole community respiration of the added C and to trace the isotope label into faunal and bacterial biomass. Similar respiration rates were found in Loch Etive and on the Ythan sand flat (0.64 ± 0.04 and 0.63 ± 0.12 mg C m−2h−1, respectively), which we attribute to the experiments being conducted at the same temperature. Faunal uptake of added C over the whole experiment was markedly greater in Loch Etive (204 ± 72 mg C m−2) than on the Ythan sand flat (0.96 ± 0.3 mg C m−2), and this difference was driven by a difference in both faunal biomass and activity. Conversely, bacterial C uptake over the whole experiment in Loch Etive was much lower than that on the Ythan sand flat (1.80 ± 1.66 and 127 ± 89 mg C m−2, respectively). This was not driven by differences in biomass, indicating that the bacterial community in the permeable Ythan sediments was particularly active, being responsible for 48 ± 18 % of total biologically processed C. This type of biological C processing appears to be favoured in permeable sediments. The total amount of biologically processed C was greatest in Loch Etive, largely due to greater faunal C uptake, which was in turn a result of higher faunal biomass. When comparing results from this study with a wide range of previously published isotope tracing experiments, we found a strong correlation between total benthic biomass (fauna plus bacteria) and total biological C processing rates. Therefore, we suggest that the total C-cycling capacity of benthic environments is primarily determined by total biomass.

scholarly journals Carbon fluxes through bacterial communities on glacier surfaces

2010 ◽  
Vol 51 (56) ◽  
pp. 32-40 ◽  
Author(s):  
Alexandre M. Anesio ◽  
Birgit Sattler ◽  
Christine Foreman ◽  
Jon Telling ◽  
Andy Hodson ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Bacterial Abundance ◽  
Heterotrophic Bacteria ◽  
Community Respiration ◽  
Organic C ◽  
C Cycle ◽  
Cryoconite Hole ◽  
Eukaryotic Organisms ◽  
Doubling Times

AbstractThere is very little information about the activity of microbial communities on the surface of glaciers, though there is an increasing body of evidence to show that they strongly influence the biogeochemistry of these habitats. We measured bacterial abundance and production in cryoconite holes on Arctic, Antarctic and Alpine glaciers in order to estimate the role of heterotrophic bacteria within the carbon budget of glacial ecosystems. Our results demonstrate an active bacterial community on the surface of glaciers with doubling times that vary from a few hours to hundreds of days depending on the glacier and position (water or sediments) within the cryoconite hole. However, bacterial production is only ∼2–3% of the published literature values of community respiration from similar habitats, indicating that other types of microbes (e.g. eukaryotic organisms) may also play a role in the C cycle of glaciers. We estimate that only up to 7% of the organic C in cryoconite sediments is utilized by the heterotrophic bacterial community annually, suggesting that the surface of glaciers can accumulate organic carbon, and that this C may be important for biogeochemical activity downstream to adjacent ecosystems.

Bacterial population dynamics, production, and heterotrophic activity in a recently formed reservoir

1999 ◽  
Vol 45 (9) ◽  
pp. 747-753 ◽  
Author(s):  
Louis B Jugnia ◽  
Rémy D Tadonléké ◽  
T Sime-Ngando ◽  
J Devaux ◽  
C Andrivon
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
Biomass Production ◽  
Resource Availability ◽  
Bacterial Production ◽  
Standing Stock ◽  
Bacterial Biomass ◽  
Heterotrophic Activity ◽  
Chlorophyll A Concentration ◽  
Biological Variables

Seasonal and spatial fluctuations in abundance, biomass production, and potential heterotrophic activity (i.e., 14C-glucose uptake) of bacterioplankton assemblages in a 1-year-old reservoir (the Sep Reservoir, Puy-de-Dôme, France) were examined concurrently with water temperature, phytoplankton chlorophyll a concentration, and primary production (PP). Based on the values observed for these biological variables, the Sep Reservoir was considered to have evolved to an oligo-mesotrophic state. Spatiotemporal variations of bacterial variables were a consequence of the seasonal evolution of the reservoir coupled with the resource availability. Multivariate regression analyses suggest that about 14 and 26% of the variance in bacterial standing stock and activity may be explained by the physical environment (i.e., temperature) and a resource availability index (chlorophyll a concentration or primary production), respectively. A carbon budget indicated that 4-126% (mean = 20%) of the ambient PP may be channeled through the microbial loop via bacterial biomass production. Heterotrophic bacterial production in the Sep Reservoir may therefore, on occasion, represent a significant source of carbon for higher order consumers.Key words: reservoirs, plankton, bacteria, heterotrophic uptake, primary and bacterial production.

The Coupling of Heterotrophic Bacterial and Phytoplankton Production in a Hypertrophic, Shallow Prairie Lake

1994 ◽  
Vol 51 (10) ◽  
pp. 2219-2226 ◽  
Author(s):  
Richard D. Robarts ◽  
Michael T. Arts ◽  
Marlene S. Evans ◽  
Marley J. Waiser
Keyword(s):  
Primary Production ◽  
Bacterial Production ◽  
Thymidine Incorporation ◽  
Chlorophyll Concentration ◽  
Bacterial Biomass ◽  
Cyanobacterial Blooms ◽  
Dominant Factor ◽  
Phytoplankton Production ◽  
Carbon Production ◽  
Prairie Lakes

Data from hypertrophic Humboldt Lake (Zmax = 6 m), Saskatchewan, support published studies indicating that bacterial numbers and production do not increase proportionally with chlorophyll concentration and primary production. There was no compensation for these relationships with increased bacterial production per cell, but our data showed an increase in production per unit bacterial biomass (273 fmol TdR∙μg C−1∙h−1). Bacterial production (19.8–422 mg C∙m−2∙d−1) was correlated with primary production (r = 0.76), and maximum bacterial production coincided with summer cyanobacterial blooms. Water temperature was a dominant factor correlated with bacterial production (r = 0.85) and growth (r = 0.92). Depending upon the factors used to convert the rate of thymidine incorporation to gross carbon production, heterotrophic bacterial production was able to consume an average of 42% (408 mg C∙m−2∙d−1) to 67% (653 mg C∙m−2∙d−1) of plankton primary productivity. Based on these calculations, hypertrophic prairie lakes might accumulate autochthonously produced organic carbon, but this conclusion takes no account of benthic bacterial production which could be high in shallow lakes.

scholarly journals Patterns of carbon processing at the seafloor: the role of faunal and microbial communities in moderating carbon flows

2016 ◽  
Author(s):  
C. Woulds ◽  
S. Bouillon ◽  
G. L. Cowie ◽  
E. Drake ◽  
Jack J. Middelburg ◽  
...  
Keyword(s):  
Bacterial Biomass ◽  
Coarse Grained ◽  
Community Respiration ◽  
Total Biomass ◽  
Coastal Zones ◽  
Organic C ◽  
Sand Flat ◽  
Permeable Sediments ◽  
C Cycling ◽  
Wide Range

Abstract. Marine sediments, particularly those located in estuarine and coastal zones, are key locations for the burial of organic carbon (C). However, organic C delivered to the sediment is subjected to a range of biological C-cycling processes, the rates and relative importance of which vary markedly between sites, and which are thus difficult to predict. In this study, stable isotope tracer experiments were used to quantify the processing of C by microbial and faunal communities in two contrasting Scottish estuarine sites: a subtidal, organic C rich site in Loch Etive with cohesive fine-grained sediment, and an intertidal, organic C poor site on an Ythan estuary sand flat with coarse- grained permeable sediments. In both experiments, sediment cores were recovered and amended with 13C labelled phytodetritus to quantify whole community respiration of the added C and to trace the isotope label into faunal and bacterial biomass. Similar respiration rates were found in Loch Etive and on the Ythan sand flat (0.64±0.04 and 0.63±0.12 mg C m−2 h−1, respectively), which we attribute to the experiments being conducted at the same temperature. Faunal uptake of added C over the whole experiment was markedly greater in Loch Etive (204±72 mg C m−2) than on the Ythan sand flat (0.96±0.3mg C m−2), and this difference was driven by a difference in both faunal biomass and activity. Conversely, bacterial C uptake over the whole experiment in Loch Etive was much lower than that on the Ythan sand flat (1.80±1.66 and 127±89 mg C m−2 respectively). This was not driven by differences in biomass, indicating that the bacterial community in the permeable Ythan sediments was particularly active, being responsible for 48±18% of total biologically processed C. This type of biological C processing appears to be favoured in permeable sediments. The total amount of biologically processed C was greatest in Loch Etive, largely due to greater faunal C uptake, which was in turn a result of higher faunal biomass. When comparing results from this study with a wide range of previously published isotope tracing experiments, we found a strong correlation between total benthic biomass (fauna plus bacteria) and total biological C processing rates. Therefore, we suggest that the total C cycling capacity of benthic environments is primarily determined by total biomass.

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

2016 ◽  
Author(s):  
Raquel Vaquer-Sunyer ◽  
Heather E. Reader ◽  
Saraladevi Muthusamy ◽  
Markus V. Lindh ◽  
Jarone Pinhassi ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Primary Production ◽  
Baltic Sea ◽  
Community Composition ◽  
Bacterial Production ◽  
Bacterial Community Composition ◽  
Treatment Plant ◽  
Community Respiration ◽  
Metabolic Rates ◽  
And Shifts

Abstract. The Baltic Sea is the largest area suffering from eutrophication-driven hypoxia. Low oxygen levels are threatening its biodiversity and ecosystem functioning. The main causes for eutrophication-driven hypoxia are high nutrient loadings and global warming. Wastewater treatment plants (WWTP) contribute to eutrophication as they are important sources of nitrogen to coastal areas. Here, we evaluated the effects of wastewater treatment plant effluent inputs on Baltic Sea planktonic communities in 4 experiments. We tested for effects of effluent inputs on chlorophyll a content, on bacterial community composition, and on metabolic rates: gross primary production (GPP), net community production (NCP), community respiration (CR) and bacterial production (BP). Nitrogen-rich dissolved organic matter (DOM) inputs from effluents increased bacterial production and decreased primary production and community respiration. Nutrient amendments and seasonally variable environmental conditions lead to lower alpha-diversity and shifts in bacterial community composition (e.g. increased abundance of a few cyanobacterial populations in the summer experiment), concomitant with changes in metabolic rates. An increase in BP and decrease in CR could be caused by high lability of the DOM that can support secondary bacterial production, without an increase in respiration. Increases in bacterial production and simultaneous decreases of primary production lead to more carbon being consumed in the microbial loop, and shifts the ecosystem towards heterotrophy.

scholarly journals Light and Primary Production Shape Bacterial Activity and Community Composition of Aerobic Anoxygenic Phototrophic Bacteria in a Microcosm Experiment

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Kasia Piwosz ◽  
Ana Vrdoljak ◽  
Thijs Frenken ◽  
Juan Manuel González-Olalla ◽  
Danijela Šantić ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Light Intensity ◽  
Bacterial Community ◽  
Primary Production ◽  
Community Composition ◽  
Bacterial Production ◽  
Bacterial Community Composition ◽  
Bacterial Activity ◽  
Bacterial Respiration ◽  
Metabolic Coupling

ABSTRACT Phytoplankton is a key component of aquatic microbial communities, and metabolic coupling between phytoplankton and bacteria determines the fate of dissolved organic carbon (DOC). Yet, the impact of primary production on bacterial activity and community composition remains largely unknown, as, for example, in the case of aerobic anoxygenic phototrophic (AAP) bacteria that utilize both phytoplankton-derived DOC and light as energy sources. Here, we studied how reduction of primary production in a natural freshwater community affects the bacterial community composition and its activity, focusing primarily on AAP bacteria. The bacterial respiration rate was the lowest when photosynthesis was reduced by direct inhibition of photosystem II and the highest in ambient light condition with no photosynthesis inhibition, suggesting that it was limited by carbon availability. However, bacterial assimilation rates of leucine and glucose were unaffected, indicating that increased bacterial growth efficiency (e.g., due to photoheterotrophy) can help to maintain overall bacterial production when low primary production limits DOC availability. Bacterial community composition was tightly linked to light intensity, mainly due to the increased relative abundance of light-dependent AAP bacteria. This notion shows that changes in bacterial community composition are not necessarily reflected by changes in bacterial production or growth and vice versa. Moreover, we demonstrated for the first time that light can directly affect bacterial community composition, a topic which has been neglected in studies of phytoplankton-bacteria interactions. IMPORTANCE Metabolic coupling between phytoplankton and bacteria determines the fate of dissolved organic carbon in aquatic environments, and yet how changes in the rate of primary production affect the bacterial activity and community composition remains understudied. Here, we experimentally limited the rate of primary production either by lowering light intensity or by adding a photosynthesis inhibitor. The induced decrease had a greater influence on bacterial respiration than on bacterial production and growth rate, especially at an optimal light intensity. This suggests that changes in primary production drive bacterial activity, but the effect on carbon flow may be mitigated by increased bacterial growth efficiencies, especially of light-dependent AAP bacteria. Bacterial activities were independent of changes in bacterial community composition, which were driven by light availability and AAP bacteria. This direct effect of light on composition of bacterial communities has not been documented previously.

scholarly journals Drivers of Microbial Carbon Fluxes Variability in Two Oligotrophic Mediterranean Coastal Systems

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Natalia González-Benítez ◽  
Lara S. García-Corral ◽  
Xosé Anxelu G. Morán ◽  
Jack J. Middelburg ◽  
Marie Dominique Pizay ◽  
...  
Keyword(s):  
Bacterial Production ◽  
Trophic Status ◽  
Carbon Sources ◽  
Growth Efficiency ◽  
Carbon Fluxes ◽  
Bacterial Metabolism ◽  
Bacterial Growth Efficiency ◽  
Community Respiration ◽  
Bacterial Respiration ◽  
Coastal Systems

AbstractThe carbon fluxes between phytoplankton and heterotrophic bacterioplankton were studied in two coastal oligotrophic sites in the NW Mediterranean. Phytoplankton and bacterial production rates were measured under natural conditions using different methods. In the Bay of Villefranche, the temporal variability revealed net heterotrophy in July-October and net autotrophy in December-March. The spatial variability was studied in the Bay of Palma, showing net autotrophic areas in the west and heterotrophic areas in the east. On average bacterial respiration, represented 62% of the total community respiration. Bacterial growth efficiency (BGE) values were significantly higher in autotrophic conditions than in heterotrophic ones. During autotrophic periods, dissolved primary production (DPP) was enough to sustained bacterial metabolism, although it showed a positive correlation with organic carbon stock (DOC). Under heterotrophic conditions, DPP did not sustain bacterial metabolism but bacterial respiration correlated with DPP and bacterial production with DOC. Temperature affected positively, DOC, BGE, bacterial respiration and production when the trophic status was autotrophic. To summarize, the response of bacterial metabolism to temperature and carbon sources depends on the trophic status within these oligotrophic coastal systems.

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

2016 ◽  
Vol 13 (16) ◽  
pp. 4751-4765 ◽  
Author(s):  
Raquel Vaquer-Sunyer ◽  
Heather E. Reader ◽  
Saraladevi Muthusamy ◽  
Markus V. Lindh ◽  
Jarone Pinhassi ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Primary Production ◽  
Baltic Sea ◽  
Community Composition ◽  
Bacterial Production ◽  
Bacterial Community Composition ◽  
Treatment Plant ◽  
Community Respiration ◽  
Metabolic Rates ◽  
The Baltic

Abstract. The Baltic Sea is the world's largest area suffering from eutrophication-driven hypoxia. Low oxygen levels are threatening its biodiversity and ecosystem functioning. The main causes for eutrophication-driven hypoxia are high nutrient loadings and global warming. Wastewater treatment plants (WWTP) contribute to eutrophication as they are important sources of nitrogen to coastal areas. Here, we evaluated the effects of wastewater treatment plant effluent inputs on Baltic Sea planktonic communities in four experiments. We tested for effects of effluent inputs on chlorophyll a content, bacterial community composition, and metabolic rates: gross primary production (GPP), net community production (NCP), community respiration (CR) and bacterial production (BP). Nitrogen-rich dissolved organic matter (DOM) inputs from effluents increased bacterial production and decreased primary production and community respiration. Nutrient amendments and seasonally variable environmental conditions lead to lower alpha-diversity and shifts in bacterial community composition (e.g. increased abundance of a few cyanobacterial populations in the summer experiment), concomitant with changes in metabolic rates. An increase in BP and decrease in CR could be caused by high lability of the DOM that can support secondary bacterial production, without an increase in respiration. Increases in bacterial production and simultaneous decreases of primary production lead to more carbon being consumed in the microbial loop, and may shift the ecosystem towards heterotrophy.

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