Longterm changes in coastal zoobenthos in the northern Baltic Sea: the role of abiotic environmental factors

We investigated site-specific changes in a coastal zoobenthic community during 1964–2007 in the northern Baltic Sea. Multivariate analysis indicated that the community structure had changed. The amphipods Monoporeia affinis and Pontoporeia femorata decreased drastically in the late 1970s–early 1980s, and by the early 1990s P. femorata vanished and M. affinis abundance was low. The decline of M. affinis and P. femorata was followed by an increase of the bivalve Macoma balthica and the arrival of the polychaete genus Marenzelleria in the 1990s. Trend analyses showed a rising trend for near-bottom temperature from the late 1960s. There was a sig-nificant decline in salinity during the early 1980s, which stabilized during the early 1990s. A negative trend was observed for oxygen concentration during the entire study period. There were interannual variations in the phosphorus and nitrogen concentrations, and a step-like increase in phosphorus concentration at the beginning of the 21st century. The correlations of temperature, salinity, oxygen