9521231 WAKEHAM Degradation rate constants for several planktonic lipid compound will be investigated under controlled laboratory conditions. Activity of benthic animals was the most likely factor causing the difference observed between rate constants in oxic and anoxic sediments profiles measured in the field. Animals can alter oxic/anoxic boundaries, control material transport processes, directly or indirectly affect microbial populations, and directly consume organic detritus. Differences under oxic versus anoxic conditions in remineralization efficiency and formation of intermediate products show that degradation follows different pathways. Research will specially consider the effects on degradation and preservation of planktonic lipids of grazing, bioturbation and oscillation between oxic and anoxic conditions caused by benthic animals. Radiolabelled tracers degradation rates and pathways under various influences of benthic animals. Further intensive study of the structure of metabolites produced during incubation experiments will provide a more detailed picture of the degradation of these important compounds.