|Long-term soft-bottom faunal changes in three shallow fjords, West Sweden|
Josefson, A.B.; Rosenberg, R. (1988). Long-term soft-bottom faunal changes in three shallow fjords, West Sweden. Neth. J. Sea Res. 22(2): 149-159
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579, more
Three West Swedish fjords were investigated at the same 14 stations in 1976 and 1986, and 8 of these had been investigated in the 1920's. The stations are situated at 7 to 27 m water depths in protected areas without any significant local pollution input, but now with organically enriched sediments. Comparisons of benthic fauna between 1976 and 1986 showed the following significant reductions: in total mean abundance and biomass (excluding some large and rare species); in abundance and biomass of molluscs; in abundance of suspension feeders and carnivores. Similarity indices gave significant differences between 1976 and 1986, and between the 1920's and both 1976 and 1986. The greatest changes had occurred in the two fjords with the most restricted water circulation. Although these faunal changes may be attributed to several factors, recently increased periods of hypoxia in the bottom water, which could be a result of large-scale eutrophication, are suggested as the main impact on the benthos.