Differential retention and utilization of dissolved organic carbon by bacteria in river sediments

Fischer, Helmut; Sachse, Anke; Steinberg, Christian E. W.; Pusch, Martin

doi:10.4319/lo.2002.47.6.1702

Cited by 133 publications

(79 citation statements)

References 47 publications

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“…The high population density, ''buffering'' by extracellular material, preservation of enzymes, and even cellto-cell signals should all contribute to the ability of biofilms to metabolize novel compounds or respond quickly to pulsed inputs (Fischer 2003). Adsorption of compounds from overlying water and movement of water through macropores in the biofilm are physical mechanisms that should enhance the capacity of the biofilm to retain solutes.…”

Section: Discussionmentioning

confidence: 99%

Metabolic and structural response of hyporheic microbial communities to variations in supply of dissolved organic matter

Findlay

Sinsabaugh

Sobczak

et al. 2003

Limnology & Oceanography

205

124

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Hyporheic sediment bacterial communities were exposed to dissolved organic matter (DOM) from a variety of sources to assess the interdependence of bacterial metabolism and community composition. Experiments ranged from small-scale core perfusions with defined compounds (glucose, bovine serum albumin) to mesocosms receiving natural leaf leachate or water from different streams. Response variables included bacterial production, oxygen consumption, extracellular enzyme activity, and community similarity as manifest by changes in banding patterns of randomly amplified polymorphic DNA (RAPD). All DOM manipulations generated responses in at least one metabolic variable. Additions of both labile and recalcitrant materials increased either oxygen consumption, production, or both depending on background DOM. Enzyme activities were affected by both types of carbon addition with largest effects from the labile mixture. Cluster analysis of RAPD data showed strong divergence of communities exposed to labile versus recalcitrant DOM. Additions of leaf leachate to mesocosms representing hyporheic flowpaths caused increases in oxygen consumption and some enzyme activities with weaker effects on production. Community structure was strongly affected; samples from the leachate-amended mesocosms clustered separately from the control samples. In mesocosms receiving water from streams ranging in DOC (0.5-4.5 mg L Ϫ1 ), there were significant differences in bacterial growth, oxygen consumption, and enzyme activities. RAPD analysis showed strongest clustering of samples by stream type with more subtle effects of position along the flowpaths. Responses in community metabolism were always accompanied by shifts in community composition, suggesting carbon supply affects both functional and structural attributes of hyporheic bacterial communities.

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Section: Discussionmentioning

confidence: 99%

Metabolic and structural response of hyporheic microbial communities to variations in supply of dissolved organic matter

Findlay

Sinsabaugh

Sobczak

et al. 2003

Limnology & Oceanography

205

124

View full text Add to dashboard Cite

show abstract

“…DOC was quantified by liquid chromatography followed by organic carbon detection (LC-OCD). This technique fractionates DOC via size-exclusion chromatography and allows separation and quantification of various groups of DOC, namely polysaccharides, humic substances, low-molecular-weight carboxylic acids and low-molecular-weight amphiphilic substances (Fischer et al 2002a).…”

Section: Methodsmentioning

confidence: 99%

“…There is evidence that DOC concentration and composition are involved in the control of microbial activity in riverine sediments (Findlay & Sobczak 2000, Fischer et al 2002a). However, we found no significant differences in total DOC and DOC fractions of interstitial water samples between the morphodynamic zones of the subaqueous dune.…”

Section: Factors Determining Microbial Activitymentioning

confidence: 99%

Microbial activity within a subaqueous dune in a large lowland river (River Elbe, Germany)

Wilczek¹,

Fischer²,

Brunke³

2004

Aquat. Microb. Ecol.

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Microbial processes within subaqueous dunes of large rivers are important for organic matter retention and decomposition but have rarely been examined. We investigated 3 morphodynamically defined zones (stoss side, crestal plateau, and lee side) within a subaqueous dune in the 8th-order River Elbe. Analysis of flow velocity, vertical hydraulic gradient, concentration of mobile fine interstitial particles, and the quantity and biochemical quality of sedimentary organic matter indicated that the stoss and the lee sides of the dune were focal zones of particulate matter retention due to infiltration and sedimentation processes. Bacterial abundance and most measures of microbial activity (sediment community respiration and activities of the extracellular enzymes β-glucosidase, leucine aminopeptidase, β-xylosidase, and exo-1, 4-β-glucanase) were significantly higher in these zones than in the plateau. Increases in bacterial abundance and microbial activity were closely correlated with protein, carbohydrates, nitrogen and phaeopigments associated with high-quality particulate organic matter. Our findings showed that the morphodynamic differentiation of the subaqueous dune resulted in the formation of distinct functional zones in the sediment. The underlying mechanisms can be conceptually summarized by a 2-stage regulatory hierarchy. Microbial activities were controlled directly by the input of dissolved oxygen and easily degradable microbial substrates, and indirectly by hydromorphological processes. We conclude that the subaqueous dune functioned as an efficient filter of particulate organic matter, and that the stoss and the lee sides of this river bedform were focal sites of microbial carbon mineralisation in the large river ecosystem.

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“…Either DOC released by resuspension was temporarily exhausted or resuspended particles removed it by adsorption onto their surface. In addition, heterotrophic bacteria utilize DOC as nutritional source in the River Spree sediments (Fischer et al 2002).…”

Section: Discussionmentioning

confidence: 99%

Intermittent riverine resuspension: Effects on phosphorus transformations and heterotrophic bacteria

Kleeberg

Hupfer

Gust

et al. 2013

Limnology & Oceanography

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Intermittent riverine resuspension (IRR), a common phenomenon, was applied to investigate its effects on sedimentary resources availability and bacteria in the water column. This lab experiment used organic-rich lowland river sediment in a newly designed erosion chamber, the Benthic Water Column Simulator, generating well-defined ratios of shear velocity u* to turbulence intensity. Eight consecutive resuspension events, 1-8, were initiated at u* 5 1.1 cm s 21 . Sedimentary and phosphorus entrainment decreased from 20.4 g m 22 h 21 and 111.6 mg m 22 h 21 at event 1 to 1.31 g m 22 h 21 and 18.7 mg m 22 h 21 at event 8, suggesting an exhaustion of particulate and dissolved sediment constituents. Entrainment of particle-associated (PA) bacteria (132.7 3 10 9 -251.1 3 10 9 cells m 22 h 21 ) was strongly correlated to that of particles. Free-living (FL) bacteria (227.6 3 10 9 -36.4 3 10 9 cells m 22 h 21 ) were fractionally entrained. Numbers of PA bacteria remained low after each event, whereas those of FL bacteria strongly increased 5-15 h after an event because of growth due to increased availability of dissolved organic carbon and inorganic nutrients following each event. FL bacteria community structure also changed during IRR. The systematic changes over consecutive IRR cycles show a strong effect in all considered parameters that elude the typical single-event, steady-state experiments. IRR should thus be considered in two respects: experimental protocols on riverine water quality should be revised. In ecosystem modeling, IRR should be considered to better predict extent and effect of resuspension. Only IRR adequately reflects the natural interplay between hydrodynamics and organisms in rivers.

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Differential retention and utilization of dissolved organic carbon by bacteria in river sediments

Cited by 133 publications

References 47 publications

Metabolic and structural response of hyporheic microbial communities to variations in supply of dissolved organic matter

Metabolic and structural response of hyporheic microbial communities to variations in supply of dissolved organic matter

Microbial activity within a subaqueous dune in a large lowland river (River Elbe, Germany)

Intermittent riverine resuspension: Effects on phosphorus transformations and heterotrophic bacteria

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