Land use in acid sulphate soils degrades river water quality – Do the biological quality metrics respond?

Land use in the Acid Sulphate (AS) soils induces metal and acidity pollution of aquatic ecosystems coastal areas worldwide. Increasing utilization AS poses increasing risks for deterioration water bodies. We studied effects coverage soils, together with other catchment land cover attributes, on assemblages fish, diatoms benthic invertebrates 42 sites along 15 lowland rivers Finland during three subsequent years. Low pH content several metals river were related to high amount catchment. Especially iron color correlated forested catchment, whereas lower values higher arsenic, chromium concentrations associated wetlands. The assemblage structure all biological groups was strongly spatially structured among varied less temporally. spatial fish affected by acidic water, more low alkalinity organic matter iron. invertebrate bioassessment metrics demonstrated soil induced degradation responding acidity, while response from index weaker. alone did not seem add biometrics without further increase acidification. Our results highlight importance recognizing target mitigation effects. A holistic approach adverse is needed, using methods directing main efforts protection human disturbance highest proportion soils. suggest that status assessment should be based multiple quality elements their could improved better detection impacts pressures. examined.