|Simulated degradation of phytodetritus in deep-sea sediments of the NE Atlantic (47 degree N, 19 degree W)|
Poremba, K. (1994). Simulated degradation of phytodetritus in deep-sea sediments of the NE Atlantic (47 degree N, 19 degree W). Mar. Ecol. Prog. Ser. 105(3): 291-299
In: Marine Ecology Progress Series. Inter-Research: Oldendorf/Luhe. ISSN 0171-8630, more
Abundance; Bacteria; Biodegradation; Biogeochemical cycle; Carbon 14; Carbon dioxide; Detritus; Mineralization; Phytobenthos; Seasonal variations; Sediment chemistry; Vertical profiles; Marine
The degradation of phytodetritus in the deep sea was studied in sediment samples of the NE Atlantic in spring and summer 1992 using 14C-labelled algal cells (Anacystis) fed to the benthic population in ship-board experiments and measuring the liberation of labelled 14CO2 over time. The mineralization process showed a 2-step behaviour with an initial rapid rate which later slowed down, indicating the initial attack of easily degradable material of the complex food and the later utilization of less labile matter. The profile of degradation activity with sediment depth showed no clear vertical gradient in March, but in August the activity in the top horizon increased by a factor of 6.1 to 7.8, which was coherent with increased bacterial numbers or biomass (factor of 1.3 to 1.7), respectively, and might be caused by the seasonal input of phytodetritus to the deep-sea bottom. The degradation measured was positively influenced by elevated incubation pressure mostly in summer, indicating that the summer stimulation of microbial activity in 1992 was based on the metabolic activation of the indigenous benthic community, while surface-derived organisms attached to sedimented particles were of lesser importance with respect to consumption of phytodetritus.