The North Sea benthic system: a 36 year time-series

Abstract

Since 1971 the macro-benthic infauna at Station P, 18.5 km off the Northumberland coast (central western North Sea), have been sampled by grabbing each January/February. The data series now includes over 260 taxa from 173 genera. The most abundant taxa are Heteromastus, Levinsinia and Priospio which between them account for nearly 45% of the individuals recorded while the top 10 ranked taxa between them include almost 70% of the individuals recorded. Both total abundance and genera richness have varied through the 36 year series, particularly during the late 1980s–early 1990s but there was no trend and values in the 2000s are similar to those at the start of the series. However, MDS ordination of the entire genera abundance series shows a trend in composition of the macrobenthos through time. There is evidence that the changes in composition were driven by fishing impacts, but also influenced by the trend in climate warming and altered fluxes of phytoplankton to the benthos. Given that the dominant taxa have not changed and the total abundance and richness are similar this implies a turnover and redistribution of individuals across many taxa and raises the possibility of shifts in the ecological functioning of the system.