Growth rates of the bivalve Macoma balthica in the Wadden Sea during a period of eutrophication: relationships with concentrations of pelagic diatoms and flagellates

Abstract

Probably as a consequence of eutrophication, both the length of the annual phytoplankton blooms and the mean concentrations of flagellates (dominated by Phaeocystis pouchetii) have increased in the western part of the Wadden Sea during the last decades. Planktonic diatoms have hardly increased, but fluctuate heavily from year to year. Among the benthic tidal-flat fauna, which has increased in total numbers and biomass during the last decades, Macoma balthica was studied in detail. Fluctuations in M. balthica parallel fluctuations of planktonic diatoms but not those of P. pouchetii responded by faster growth and higher condition to better feeding conditions in years of high diatom abundance. -from Authors