AWI North Sea benthos time series

Since 1969 the benthic infauna has been monitored on four Stations in the German Bight. The stations have been positioned in a way that all major sediment types of the German Bight are covered. Sampling is seasonal (spring, summer, autumn), however, not all seasons have been covered in each year when bad weather conditions prevented sampling. An analysis of the data showed that the structural composition of the benthic infauna communities in the German Bight is subject to substantial inter-annual fluctuations on a decadal scale. The variations correlate temporally with the North Atlantic Oscillation (NAO) Index indicating a link between the benthic community structure and climate. This is supported by the sensitivity of the benthic communities towards exceptionally severe winters. The changes of the community structures do not occur spontaneously but develop gradually over time scales of several years. Additionally, a sensitivity of the benthic communities towards eutrophication was inferred from an elevated mortality of benthic organisms caused by reduced oxygen concentrations due to the decomposition of organic matter from primary production.