Bacterial carbon sources in coastal sediments: a review based on stable isotope data of biomarkers

Abstract

Coastal ecosystems are typically highly productive, and recieve organic matter from a variety of local and imported sources. To assess if general patterns are present in the origin of carbon sources for sedimentary bacteria and their relation to the origin of the sediment organic carbon pool, we compiled both literature and new data on δ 13 C 5 of bacterial biomarker PLFA (the phospholipid derived fatty acids i +a15:0) along with δ 13 C data on sediment organic carbon (δ 13 C TOC) and macrophyte biomass. Such data were collected from a variety of typical near-coastal systems, including mangroves, salt marshes (both C3 and C4-dominated sites), seagrass beds, and macroalgae-based systems, as well as unvegetated sediments. First, our δ 13 C i +a15:0 data showed a large 10