Dynamics of microphytobenthos biomass in the Ems Estuary

Abstract

Mean annual concentrations of chl a ranged from 28.6-247.0 mg m-2 in the top 0.5 cm of sediment. The lowest value of the mean annual biomass of microphytobenthos per station was 3.1 g C m-2, and the highest was 16.7 g C m-2. Average values over the total period investigated ranged from 3.2-11.0 g C m-2. With one exception where a value of 0.6 was calculated, the ratio between the biomass from the 0.5-2.0 cm sediment layer and that from the 0-2 cm sediment layer was fairly constant (0.40-0.47). Sampling only the top 0.5cm of the sediment to determine the microphytobenthos chl a and multiplying this value by the corresponding C/chl a ratio results in the carbon biomass being grossly (40-60%) underestimated. Use of an incorrect C/chl a ratio (which varied between 40-61 during the study period) in this calculation can increase this deviation by a further 50%). -from Authors