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Media type:
E-Article
Title:
The Baltic Sea: Current and Future Status and Impact of Agriculture
Contributor:
Jansson, Bengt-Owe
imprint:
Royal Swedish Academy of Sciences, 1997
Published in:Ambio
Language:
English
ISSN:
0044-7447;
1654-7209
Origination:
Footnote:
Description:
<p>A large, densely populated catchment area dominating water quality of land runoff, stratification of the brackish water, a residence time of 25 years, intermittent renewal of oxygenated bottom water from the North Sea, few plant and animal species already stressed by low salinity, make the Baltic Sea vulnerable to changes in external forcings such as increased inputs of nutrients and toxic substances. A severalfold increase of nutrient inputs and primary production since the beginning of the century has increased the area of anoxic bottoms, decreased the transparency of the water by 2.5-3 m, favored filamentous annual algae at the expense of coarse, perennial ones-like the important bladderwrack (Fucus vesiculosus)-changed the fish community from cod, salmon, pike and perch toward herring, sprat, bream, and roach. Because they are a major source of external nitrogen, a shift in current agricultural practices has to be made including: tree curtains to increase patchiness, biodiversity and natural pest control; catch crops along rivers; matching animal density and crop types to achieve optimal recycling of nutrients. So far, integrated land use, based on operative ecological-socioeconomic models, is the most powerful policy instrument for a sustainable agriculture.</p>