Changes in bacterial processing and composition of dissolved organic matter in a newly-flooded reservoir (a three-year study)

Richardot, Mathilde; Debroas, Didier; Jugnia, Louis‐B.; Tadonléké, Rémy D.; Berthon, L.; Dévaux, Jean

doi:10.1127/archiv-hydrobiol/148/2000/231

Cited by 22 publications

(27 citation statements)

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“…Different regions of the reservoir may have different CO 2 dynamics because of flooded biomass, river input of organic matter, primary production and dam operations. Furthermore, both heterotrophic and autotrophic activities influence the CO 2 concentrations along reservoirs located in subtropical (Di Siervi et al, 1995), tropical (Roland et al, 2010;Kemenes et al, 2011) and temperate areas (Richardot et al, 2000;Lauster et al, 2006;Finlay et al, 2009;Halbedel and Koschorreck, 2013). As sedimentation and light availability increase along a reservoir, the biomass of the primary producers may increase.…”

Section: Introductionmentioning

confidence: 99%

The effects of river inflow and retention time on the spatial heterogeneity of chlorophyll and water–air CO<sub>2</sub> fluxes in a tropical hydropower reservoir

et al. 2015

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Abstract. Abundant research has been devoted to understanding the complexity of the biogeochemical and physical processes that are responsible for greenhouse gas (GHG) emissions from hydropower reservoirs. These systems may have spatially complex and heterogeneous GHG emissions due to flooded biomass, river inflows, primary production and dam operation. In this study, we investigated the relationships between the water-air CO 2 fluxes and the phytoplanktonic biomass in the Funil Reservoir, which is an old, stratified tropical reservoir that exhibits intense phytoplankton blooms and a low partial pressure of CO 2 (pCO 2 ). Our results indicated that the seasonal and spatial variability of chlorophyll concentrations (Chl) and pCO 2 in the Funil Reservoir are related more to changes in the river inflow over the year than to environmental factors such as air temperature and solar radiation. Field data and hydrodynamic simulations revealed that river inflow contributes to increased heterogeneity during the dry season due to variations in the reservoir retention time and river temperature. Contradictory conclusions could be drawn if only temporal data collected near the dam were considered without spatial data to represent CO 2 fluxes throughout the reservoir. During periods of high retention, the average CO 2 fluxes were 10.3 mmol m −2 d −1 based on temporal data near the dam versus −7.2 mmol m −2 d −1 with spatial data from along the reservoir surface. In this case, the use of solely temporal data to calculate CO 2 fluxes results in the reservoir acting as a CO 2 source rather than a sink. This finding suggests that the lack of spatial data in reservoir C budget calculations can affect regional and global estimates. Our results support the idea that the Funil Reservoir is a dynamic system where the hydrodynamics represented by changes in the river inflow and retention time are potentially a more important force driving both the Chl and pCO 2 spatial variability than the in-system ecological factors.

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Section: Introductionmentioning

confidence: 99%

The effects of river inflow and retention time on the spatial heterogeneity of chlorophyll and water–air CO<sub>2</sub> fluxes in a tropical hydropower reservoir

et al. 2015

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“…The DOM concentrations in the recently flooded Sep Reservoir were higher than those measured in other lakes of similar trophic status, i.e. oligotrophic to oligo-mesotrophic (Richardot et al, 1999(Richardot et al, , 2000. The DCAA concentrations were in fact higher than any cited in the literature, which are usually between 0.1 and 2.9 mg C l )1 (Striquer-Soares & Chevolot, 1996).…”

Section: Concentrations Role and Origin Of Dommentioning

confidence: 67%

“…All this would explain the observed lack of correlation between DOM component concentrations, and either diel variations or differences between sampling depths. A study conducted from 1996 to 1998 in this system indicated that polysaccharides and DCCHO from an allochtonous source controlled BP (Richardot et al, 2000). Despite the importance of DOM at a pluriannual scale, diel fluctuations of polysaccharides during this study could not be related to the periodicity in BP, suggesting the presence of high concentrations of DOM components from other sources including viral lysis of bacterial and algal cells, excretion from protozoan, zooplankton and higher trophic level.…”

Section: Concentrations Role and Origin Of Dommentioning

confidence: 87%

“…In a newly-flooded reservoir, DOM seems to play a key role in controlling bacterial communities through resources (Paterson et al, 1997;Richardot et al, 2000). The DOM concentrations in the recently flooded Sep Reservoir were higher than those measured in other lakes of similar trophic status, i.e.…”

Section: Concentrations Role and Origin Of Dommentioning

confidence: 87%

“…TDCHO minus DFCHO gave dissolved combined carbohydrates (DCCHO) (the coefficients of variation for the DCHO analysis varied between 0.7 and 7.0%). Organic carbon concentrations were calculated assume to 1 mg Glu corresponds to 0.4 mg carbon, and 1 mg BSA coresponds to 0.5 mg carbon (Richardot et al, 2000). Blanks with carbon-free distilled water were processed in parallel, and the value obtained in each native sample was corrected to its respective blank.…”

Section: Physico-chemical Variablesmentioning

confidence: 99%

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Bacterial Production in the Recently Flooded Sep Reservoir: Diel Changes in Relation to Dissolved Carbohydrates and Combined Amino Acids

et al. 2006

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Key words: bacteria, carbohydrates, combined amino acids, new reservoir, phytoplankton AbstractThe spatial distribution of bacterial abundance and production were measured every 4 h in a recently flooded oligo-mesotrophic reservoir (the Sep Reservoir, Puy-De-Doˆme, France), in relation to concentrations of dissolved carbohydrates and combined amino acids. The concentration of dissolved organic matter (DOM) components in the recently flooded Sep Reservoir were higher than those measured in other lakes of similar trophic status. Short-term variations in the bacterial production in this new reservoir appeared cyclical and endogenous to bacterial communities. These results highlight the need for the evaluation of diel changes in bacterial production, if estimation of the daily production rate of bacteria is to be done accurately for a reliable model of carbon flow through bacterioplankton and ultimately through aquatic microbial food webs. Bacterial growth, measured over time and space, did not appear exclusively governed by DOM components from phytoplankton primary production.

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Variability of carbon dioxide flux from tropical (Cerrado) hydroelectric reservoirs

et al. 2010

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Hydroelectric reservoirs generate energy without significant combustion of fossil fuels. However, these systems can, potentially, emit greenhouse gases (GHG's) at a rate which may be significant at the global scale, and, possible, co-equal, per kilowatt-hour, to that from conventional coal or oil-fired systems. Although much of the new construction of hydroelectric reservoirs is in the tropics, most of the data on GHG emissions comes from temperate regions. Further, much of the existing data on reservoir gas emissions comes from single sites, usually near the terminal dams. Large tropical reservoirs often involve the impoundments of river systems with complex morphology which in turn can cause spatial heterogeneity in gas flux. We evaluated spatial and seasonal variability in CO 2 concentrations and gas flux for five large (50-1,400 km 2 ) reservoirs in the Cerrado region of Brazil. Most of data set (87% of all measurements) showed CO 2 supersaturation and net efflux to the atmosphere. There was as much or more variation in pCO 2 over space and among seasons. The large studied reservoirs showed different zones in terms of CO 2 emission because those fluxes are dependent on flooded biomass, watershed input of organic matter and dam operation regime. Here we demonstrate that the reservoirs in the Brazilian Cerrado have low rates of CO 2 emissions compared to existing global comparisons. Our results suggest that ignoring the spatial variability can lead to more than 25% error in total system gas flux.

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Changes in bacterial processing and composition of dissolved organic matter in a newly-flooded reservoir (a three-year study)

Cited by 22 publications

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The effects of river inflow and retention time on the spatial heterogeneity of chlorophyll and water–air CO<sub>2</sub> fluxes in a tropical hydropower reservoir

The effects of river inflow and retention time on the spatial heterogeneity of chlorophyll and water–air CO<sub>2</sub> fluxes in a tropical hydropower reservoir

Bacterial Production in the Recently Flooded Sep Reservoir: Diel Changes in Relation to Dissolved Carbohydrates and Combined Amino Acids

Variability of carbon dioxide flux from tropical (Cerrado) hydroelectric reservoirs

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Changes in bacterial processing and composition of dissolved organic matter in a newly-flooded reservoir (a three-year study)

Cited by 22 publications

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The effects of river inflow and retention time on the spatial heterogeneity of chlorophyll and water–air CO&lt;sub&gt;2&lt;/sub&gt; fluxes in a tropical hydropower reservoir

The effects of river inflow and retention time on the spatial heterogeneity of chlorophyll and water–air CO&lt;sub&gt;2&lt;/sub&gt; fluxes in a tropical hydropower reservoir

Bacterial Production in the Recently Flooded Sep Reservoir: Diel Changes in Relation to Dissolved Carbohydrates and Combined Amino Acids

Variability of carbon dioxide flux from tropical (Cerrado) hydroelectric reservoirs

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The effects of river inflow and retention time on the spatial heterogeneity of chlorophyll and water–air CO<sub>2</sub> fluxes in a tropical hydropower reservoir

The effects of river inflow and retention time on the spatial heterogeneity of chlorophyll and water–air CO<sub>2</sub> fluxes in a tropical hydropower reservoir