Temporal and spatial large-scale effects of eutrophication and oxygen deficiency on benthic fauna in Scandinavian and Baltic waters - A review

摘要: Eutrophication has been an increasing ecological threat during the past 50 yr in many Scandinavian and Baltic marine waters. Large sedimentary areas are seasonally, or more less permanently, affected by hypoxia and/or anoxia with devastating effects on benthic macrofauna in, for example, Sea, Belt Seas Oresund between Denmark Sweden, Kattegat Skagerrak coast towards North Sea. In this review figures input of nitrogen phosphorus to different sea presented, several cases also changes concentrations water. The nutrient is related production levels, macrobenthic infauna. Changes dominant species, abundance biomass presented relation both organic enrichment time space. Since 1950s-60s, faunal increased Gulf Bothnia as a result enrichment. Aland Archipelago, number species decreased since 1970s but increased. Drifting algae at sediment surface problem. were caused eutrophication. Finnish Archipelago large-scale eutrophication resulted periodic bottom water drifting algal mats negative fauna. Finland, fauna negatively hypoxic below 70 depth 1960s, period improved oxygen conditions 1987-94. Proper, large sea-bed 000-100 000 km(2) 70-80 have anoxic 1960s no reduced sediment-dwelling This process was lack larger inflows oxygenated from Kattegat. Several coastal basins southern (e.g. Bornholm Basin, Arkona Basin Kiel Bay), have, occasions, similarly Many similar 17 Danish seasonal consequences On coast, Limfjord, Mariager fjord Roskilde particularly affected. southeast, open Kattegat, nutrients combination stratification 1980 animals commercial fish most years. fjords Swedish Norwegian shown temporal trends concentrations, some them deeper parts months more. development discussed consequent possible losses roughly calculated. total investigated, worst years combined may macrofaunal 3 million t. loss partly compensated increase that occurred well-flushed organically enriched areas. Tolerance their strategies cope H2S.