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The influence of sediment oxygen heterogeneity, due to bioturbation, on diffusive oxygen flux was investigated. Laboratory experiments were carried out with 3 macrobenthic species presenting different bioturbation behaviour patterns: the polychaetes Nereis diversicolor and Nereis virens, both constructing ventilated galleries in the sediment column, and the(More)
4 2 4 2 Abstract—Pore water and solid phase distributions of oxygen, manganese, and nitrogen from hemipelagic and shelf sediments sometimes indicate a close coupling between the manganese and nitrogen redox cycles. Reaction coupling must be sustained in part by biological reworking of Mn-oxide-rich surface sediments into underlying anoxic zones. Surface(More)
To study the impact of oxygen regimes on the removal of polycylic aromatic hydrocarbons (PAHs) in oil-spill-affected coastal marine sediments, we used a thin-layer incubation method to ensure that the incubated sediment was fully oxic, anoxic, or was influenced by oxic-anoxic switches without sediment stirring. Hydrocarbon content and microbial assemblages(More)
Impact of feeding by Arenicola marina (L.) and ageing of faecal material on fatty acid distribution and bacterial community structure in marine sediments: An experimental approach. OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. Abstract The fate of ingested(More)
The diffusive oxygen uptake (DOU) of sediments inhabited by Chironomus riparius and Tubifex tubifex was investigated using a planar oxygen optode device, and complemented by measurements of bioturbation activity. Additional experiments were performed within contaminated sediments to assess the impact of uranium on these processes. After 72h, the two(More)
The influence of macrofaunal burrow spacing and diffusive scaling on sedimentary nitrification and denitrification: An experimental simulation and model approach. OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. ABSTRACT The influence of burrow spacing on sedimentary(More)
Influence of various redox conditions on the degradation of microalgal triacylglycerols and fatty acids in marine sediments. OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. Abstract Sediment cakes, supplemented with microalgal cells (Nannochloropsis salina), were(More)
Nitrogen removal in marine environments: recent findings and future research challenges. OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. Abstract Respiratory reduction of nitrate (denitrification) is recognized as the most important process converting biologically(More)
Active organisms modify the substratum in which they dwell. This process, called “bioturbation”, affects the way that biogeochemical fluxes are mediated at the substratum–water interface. In the frame of this work, the bioturbation potential of the Asiatic clam Corbicula fluminea was characterized and quantified. We measured the displacement of fluorescent(More)
Bioturbation is known to stimulate microbial communities, especially in macrofaunal burrows where the abundance and activities of bacteria are increased. Until now, these microbial communities have been poorly characterized and an important ecological question remains: do burrow walls harbor similar or specific communities compared with anoxic and surface(More)