The Role of Plankton in the Energy Transfer to the Sediment in Dubh Lochan

Microbiology, Limnology

Islam, Abul Kalam Mohammed Sirajul

University:University of Glasgow

关键词: Microbiology, Limnology;   

Others  :  http://theses.gla.ac.uk/77576/1/10997359.pdf

来源: University of Glasgow

【 摘 要 】

The fate of photosynthetically fixed energy and the role of plankton in the energy flow to the sediment through detrital pathway is reported. Some selected physico chemical conditions of the habitat, phytoplankton and zooplankton biomass , seasonal patterns of individual species and primary production of phytoplankton were studied from October, 1983 to September, 1985. Seston biomass, composition, chemistry and energetics were studied from March, 1985 to February, 1986. Chemistry and the energetics of the sediment were studied from July, 1985 to June, 1986. Benthos biomass and energetics were studied from March, 1985 to February, 1986 Chemical conditions especially pH, conductivity, nitrate, orthophosphate and silicate showed great variations since Klarer's (1978) study, conducted 10 years earlier,, Phytoplankton biomass showed a single summer peak during June and July. Zooplankton biomass showed three distinct seasonal peaks during mid to late spring, late summer to early autumn and in late autumn to early winter. Seston biomass showed three distinct seasonal peaks during mid spring, late summer and mid autumn although high levels were also observed in winter. Nitrogen and phosphorus concentrations in the sediment were also higher at station 1 than at station 2. Both organic carbon and the energy content of the sediment were much higher during the summer months than the rest of the period. Benthos biomass showed two distinct seasonal peaks at station 1, during spring and autumn and a single summer peak at station 2. On an annual basis, 0.87% of the energy was transformed from phytoplankton to zooplankton ranging from 0.08% in October to 5.89% in February. Seventy seven percent of the energy was channelled through seston. Seston production greatly exceeded primary production from November to February, 1986. The energy transfer from primary production during late spring to mid summer was not reflected in the sediment, instead the highest level was observed in August and September when primary production was very low. Benthos production was independant of primary production in deep water at station 1 but in shallow water at station 2 , it closely followed primary production.