Observations on impaired vitality of Unio crassus (Bivalvia: Najadae) populations in conjunction with elevated nitrate concentration in running waters |
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| Authors: | Ralf Khler |
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| Institution: | Ralf Köhler |
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| Abstract: | A number of publications show relationships between impairment of vitality and reproduction as well as excessive shares of aged individuals within populations of Unio crassus with nitrate concentrations in the field. Our own examination of available data on nitrate concentrations in selected rivers of Brandenburg with known remainder populations of Unio crassus and of rivers without that species confirmed that above 2 mg L–1 NO3–‐N Unio crassus populations are impaired. Current toxicity data on nitrate do not indicate any mechanism by which the observations can be explained. Probably high NO3–‐N concentrations and the impaired production and vitality of Unio crassus populations share the same causes. These need to be identified. |
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| Keywords: | Toxicity mussel nitrogen threshold value Brandenburg |
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