Acetate in recent anoxic sediments: Direct and indirect measurements of concentration and turnover rates

Shaw, David G.; McIntosh, Douglas J.

doi:10.1016/0272-7714(90)90082-3

Cited by 32 publications

(30 citation statements)

References 21 publications

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“…5) suggests a difference between production and flux from the soils and/or errors in the rate measurements. Porewater acetate concentrations measured in both freshwater and salt-water amended soils were relatively high (exceeding 1 mmol L -1 in some cases; data not shown), which may reflect increased acetate following centrifugation of soils (Shaw and McIntosh 1990;Hines et al 1994). Artificially increased concentrations of porewater acetate would result in higher rates of AMG (Eq.…”

Section: Experimental Design Considerationsmentioning

confidence: 87%

Accelerated microbial organic matter mineralization following salt-water intrusion into tidal freshwater marsh soils

et al. 2010

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The impact of salt-water intrusion on microbial organic carbon (C) mineralization in tidal freshwater marsh (TFM) soils was investigated in a year-long laboratory experiment in which intact soils were exposed to a simulated tidal cycle of freshwater or dilute salt-water. Gas fluxes [carbon dioxide (CO 2 ) and methane (CH 4 )], rates of microbial processes (sulfate reduction and methanogenesis), and porewater and solid phase biogeochemistry were measured throughout the experiment. Flux rates of CO 2 and, surprisingly, CH 4 increased significantly following salt-water intrusion, and remained elevated relative to freshwater cores for 6 and 5 months, respectively. Following saltwater intrusion, rates of sulfate reduction increased significantly and remained higher than rates in the freshwater controls throughout the experiment. Rates of acetoclastic methanogenesis were higher than rates of hydrogenotrophic methanogenesis, but the rates did not differ by salinity treatment. Soil organic C content decreased significantly in soils experiencing salt-water intrusion. Estimates of total organic C mineralized in freshwater and salt-water amended soils over the 1-year experiment using gas flux measurements (18.2 and 24.9 mol C m -2 , respectively) were similar to estimates obtained from microbial rates (37.8 and 56.2 mol C m -2 , respectively), and to losses in soil organic C content (0 and 44.1 mol C m -2 , respectively). These findings indicate that salt-water intrusion stimulates microbial decomposition, accelerates the loss of organic C from TFM soils, and may put TFMs at risk of permanent inundation.

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Section: Experimental Design Considerationsmentioning

confidence: 87%

Accelerated microbial organic matter mineralization following salt-water intrusion into tidal freshwater marsh soils

et al. 2010

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“…A limitation due to hydrogen is, however, unlikely, because hydrogen concentrations seem to be high enough to drive bicarbonate-based methanogenesis at this depth (80-115 cm). Acetate is still abundant in the pore water of the entire core, but previous studies have demonstrated that pore water acetate is not always bioavailable (Shaw and McIntosh, 1990;Wellsbury and Parkes, 1995). Nevertheless, acetate is used as substrate for methanogenesis deeper in the core which indicates that it is unlikely to be limiting SRR.…”

Section: Regulation Of Aom Srr and Methanogenesis In Diffusive Sedimmentioning

confidence: 94%

Anaerobic oxidation of methane (AOM) in marine sediments from the Skagerrak (Denmark): I. Geochemical and microbiological analyses

Knab

Cragg

Borowski

et al. 2008

Geochimica et Cosmochimica Acta

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“…Previous studies have found that not all LMW DOC (e.g., fatty acids, amino acids) determined by chemical methods like GC and HPLC is available for microbial uptake (Sansone and Martens 1982;Lee and Jørgensen 1995). In particular, a number of studies in marine anoxic sediments have shown that calculated acetate oxidation rates can exceed the rate of CO 2 production or sulfate reduction where sulfate reduction is known to be the major organic carbon oxidation pathway (Christensen and Blackburn 1982;Shaw et al 1984;Sansone 1986;Shaw and McIntosh 1990;Wellsbury and Parkes 1995). Therefore, acetate concentrations estimated by chemical methods represent an upper limit for the amount of acetate available for microbial uptake.…”

Section: Methodsmentioning

confidence: 99%

Acetate cycling in the water column of the Cariaco Basin: Seasonal and vertical variability and implication for carbon cycling

Scranton

Taylor

et al. 2002

Limnology & Oceanography

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Acetate oxidation frequently has been used as proxy of organic carbon decomposition in marine anoxic sediments. However, the importance of acetate uptake in carbon cycling in marine anoxic water columns is less well studied. Acetate concentrations and uptake rate constants, together with total bacterial numbers, primary and chemoautotrophic production rates, and particulate organic carbon (POC) fluxes, were measured in the water column of the Cariaco Basin during upwelling and nonupwelling seasons between November 1995 and May 1999 as part of the international CARIACO (Carbon Retention In A Colored Ocean) program. Acetate uptake was found to vary strongly with depth and season. Zones of elevated acetate uptake were found in the surface waters and near the suboxic/anoxic interface. High acetate uptake in the surface oxic layer suggests that acetate cycling may be an important component of organic carbon oxidation in oxic environments as well as under anoxic conditions. Depthintegrated acetate uptake rates were correlated with the rates of organic carbon supply in the two zones (r 2 ϭ 0.37, P ϭ 0.017). Comparisons of acetate oxidation rates with rates of primary production, chemoautotrophic production, and POC flux show that, on average, acetate oxidation can account for respiration of between 16 and 46% of the organic carbon fixed in the water column.During microbial degradation of organic matter, polymers are hydrolyzed to monomers (such as amino acids, sugars, and fatty acids) before they can be taken up by bacteria. In oxic environments, a single aerobic bacterium can complete-

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Acetate in recent anoxic sediments: Direct and indirect measurements of concentration and turnover rates

Cited by 32 publications

References 21 publications

Accelerated microbial organic matter mineralization following salt-water intrusion into tidal freshwater marsh soils

Accelerated microbial organic matter mineralization following salt-water intrusion into tidal freshwater marsh soils

Anaerobic oxidation of methane (AOM) in marine sediments from the Skagerrak (Denmark): I. Geochemical and microbiological analyses

Acetate cycling in the water column of the Cariaco Basin: Seasonal and vertical variability and implication for carbon cycling

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