Community metabolism of intertidal flats in the Ems-Dollard estuary

Abstract

To obtain an insight into the flux of carbon through intertidal sediments of the Ems-Dollard estuary, the annual cycles of gross benthic primary production and community respiration were measured at six stations, together with a set of environmental parameters. In a stepwise multiple regression analysis it was shown that temperature alone and temperature plus viable bacteria explained 50 and 70% respectively of the observed variation in community respiration. Other variables, including the rate of primary production and amount of organic carbon in the sediment were less important. The rate of primary production could not be fitted adequately into a multiple regression equation. The annual values of community respiration (177–794 gO2·m-2·yr-1) and primary production (82–628 gO2·m-2·yr-1) were within the range of published values. except for one station in the vicinity of a wastewater outfall, which had an extreme production (average 984 gO2·m-2·yr-1). At four stations, annual community respiration exceeded primary production by 40%. It is concluded that the main carbon flux within the sediment, from CO2 to benthic primary producers, to benthic consumers and from there to CO2 again,was completed within a month or so, leaving untouched the large bulk of organic matter within the sediment. Possible effects of wastewater discharges on community metabolism are discussed.