Origin and composition of organic matter in tidal flat sediments from the German Wadden Sea

Freese, Elke; Köster, Jürgen; Rullkötter, Jürgen

doi:10.1016/j.orggeochem.2008.04.023

Cited by 33 publications

(24 citation statements)

References 58 publications

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“…Sediment surfaces at site JS-I were reduced as indicated by black coloration due to FeS formation (e.g., Böttcher 2003;Böttcher et al 1998). As shown by stable carbon isotope measurements on the TOC fraction, the bulk organic matter is a mixture between easily degradable marine OM and less reactive terrestrial or peatderived OM Volkman et al 2000;Peters 2004;Theune 2005;Freese et al 2008). Only the reactive fraction is degradable by microorganisms at higher rates (e.g., Schubert et al 2000;Pomeroy and Wiebe 2001).…”

Section: General Sediment and Pore Water Propertiesmentioning

confidence: 99%

“…Therefore, much lower SRR were found in continental slope and deep sea sediments (Jørgensen 1982;Boetius et al 2000). Tidal areas, in particular, represent highly productive marine coastal ecosystems that are under additional influence of riverine inputs by loads of detritus and dissolved and particulate organic matter (Vosjan 1987;Volkman et al 2000;Rullkötter 2006;Freese et al 2008). These intertidal sediments are exposed to a number of physical, biological, and chemical processes, resulting in complex and dynamic interactions between the biogeochemical element cycles.…”

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confidence: 99%

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Seasonal dynamics of microbial sulfate reduction in temperate intertidal surface sediments: controls by temperature and organic matter

et al. 2009

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The role of microbial sulfate reduction on organic matter oxidation was studied quantitatively in temperate intertidal surface sediments of the German Wadden Sea (southern North Sea) on a seasonal base in the years 1998-2007. The sampling sites represent the range of sediments found in the back-barrier tidal area of Spiekeroog Island: sands, mixed and muddy flats. The correspondingly different contents in organic matter, metals, and porosities lead to significant differences in the activity of sulfatereducing bacteria with volumetric sulfate reduction rates (SRR) in the top 15 cm of up to 1.4 μmol cm −3 day −1 .Depth-integrated areal SRR ranged between 0.9 and 106 mmol m −2 day −1 , with the highest values found in the mudflat sediments and lower rates measured in sands at the same time, demonstrating the impact of both temperature and organic matter load. According to a modeling approach for a 154-km 2 large tidal area, about 39, 122, and 285 tons of sulfate are reduced per day, during winter, spring/ autumn, and summer, respectively. Hence, the importance of areal benthic organic matter mineralization by microbial sulfate reduction increases during spring/autumn and summer by factors of about 2 and 7, respectively, when compared to winter time. The combined results correspond to an estimated benthic organic carbon mineralization rate via sulfate reduction of 78 g C m −2 year −1 .

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Section: General Sediment and Pore Water Propertiesmentioning

confidence: 99%

mentioning

confidence: 99%

Seasonal dynamics of microbial sulfate reduction in temperate intertidal surface sediments: controls by temperature and organic matter

et al. 2009

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“…In the backbarrier area of Spiekeroog Island, NW Germany, sediment and pore water biogeochemistry were studied by microbiological, molecular, and geochemical approaches (Böttcher et al 1997(Böttcher et al , 1998Volkman et al 2000;LlobetBrossa et al 2002;Rütters et al 2002;Köpke et al 2005;Billerbeck et al 2006a, b;Wilms et al 2006a, b;Bosselmann 2007;Beck et al 2008a, b, c;Freese et al 2008;Gittel et al 2008). In subsurface tidal flat sediments, key genes for dissimilatory sulfate reduction and methanogenesis were detected in the sediment down to 5 m depth.…”

Section: Introductionmentioning

confidence: 99%

Deep pore water profiles reflect enhanced microbial activity towards tidal flat margins

et al. 2009

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Microbial activity in permeable tidal flat margin sediments is enhanced by two main processes. First, organic matter is supplied by rapid sedimentation at prograding tidal flat margins. Second, surface and deep pore water advection lead to a replenishment of the dissolved organic matter and sulfate pools. Increasing microbial activity towards the low water line is reflected in sulfate and methane profiles as well as in total cell numbers, sulfate reduction rates, and remineralization products. The impact of high sedimentation rates on pore water biogeochemistry is confirmed by inverse modeling reproducing the depth profiles obtained by measurements. In central parts of the tidal flats, low sedimentation rates and pore water flow velocities limit microbial activity despite the high availability of electron acceptors for microbial respiration such as sulfate. Therefore, tidal flat margins with high microbial activity are of special importance for budgeting biogeochemical cycling in tidal flat areas.

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“…Here, the upper centimeters of the sediments but also the shallow subsurface down to 5 m depth were analyzed by geochemical approaches (Böttcher et al 1997(Böttcher et al , 1998Volkman et al 2000;Rütters et al 2002;Billerbeck et al 2006a, b;Freese et al 2008;Beck et al 2008a, b). Cultivation-based studies have identified the most abundant microorganisms that can be stimulated to grow (Köpke et al 2005;Gittel et al 2008).…”

Section: The Subsurface Of Tidal-flat Sedimentsmentioning

confidence: 99%

The subsurface of tidal-flat sediments as a model for the deep biosphere

Engelen

Cypionka

2008

Ocean Dynamics

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Subsurface sediments of tidal flats and the marine deep biosphere share several features. Although on different scales in time and space, geochemical profiles and microbial successions follow the same trends. Microbial activities are governed by the availability of electron acceptors and the quality of electron donors. Two deepbiosphere sites and a shallow site from a German North Sea tidal flat were exemplarily chosen to compare geochemical settings and microbiological features. At all sites, microbial abundance was elevated at sulfate-methane transition zones. The known discrepancy between cultivation-based and molecular diversity assessments is observed, but similar microbial community compositions are found with each of the approaches at deep and shallow sites. These findings lead to the conclusion that we are presently unable to draw a cutting line between the shallow and the deep subsurface. Rather, there appears to exist only one "subsurface biosphere" with gradual differences. Therefore, tidal flats serve as an excellent model to perform microbiological experiments and to test novel techniques before applying them to much deeper and older samples.

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Origin and composition of organic matter in tidal flat sediments from the German Wadden Sea

Cited by 33 publications

References 58 publications

Seasonal dynamics of microbial sulfate reduction in temperate intertidal surface sediments: controls by temperature and organic matter

Seasonal dynamics of microbial sulfate reduction in temperate intertidal surface sediments: controls by temperature and organic matter

Deep pore water profiles reflect enhanced microbial activity towards tidal flat margins

The subsurface of tidal-flat sediments as a model for the deep biosphere

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