Boschker, H. T.S.. Netherlands Institute of Ecology (NIOO-CEMO), boschker@cemo.nioo.knaw.nl
de Brouwer, J. T.S.. Netherlands Institute of Ecology (NIOO-CEMO),
Cappenberg, T. E.. Netherlands Institute of Ecology (NIOO-CEMO),

 
THE CONTRIBUTION OF LOCAL MACROPHYTE MATERIAL TO MICROBIAL BIOMASS IN SALT MARSH SEDIMENTS: 13C ANALYSIS OF PLFA
 
Stable carbon isotope ratios of bacterial biomarkers (PLFA, mainly i15:0 and a15:0 fatty acids) were determined to infer sources of organic carbon used by bacteria in the sediments of three salt marshes. Experiments showed that the isotopic fractionation between substrate and biomarkers was relatively constant (-4 to -6 o/oo). At the Spartina site of the Waarde Marsh (The Netherlands), biomarker 13C/12C ratios suggested that local macrophyte production was of little importance for bacterial growth, as biomarkers were more depleted by approximately 6 o/oo than expected for bacteria growing on Spartina litter and similar to an unvegetated control sediment. Local Spartina plant production contributed about half of the carbon in bacterial PLFA at the Kattendijke Marsh (The Netherlands) and dominated at the Great Marshes (USA). These differences between Spartina marshes are related to estimated inputs of non-macrophyte material of probably algal origin. At the Waarde Marsh, coupling between plant and bacteria was much more important in Scirpus maritimus than in Spartina anglica. In conclusion, the relative importance of local plant production for bacterial processes in salt marsh sediments is highly variable between marshes and plant species.
 
Day: Tuesday, Feb. 2
Time: 12:00 - 12:15pm
Location: Eldorado Hotel
 
Code: SS32TU1200E