Responses of atlantic salmon (Salmo salar) alevins to dissolved organic carbon and dissolved aluminum at low pH

Abstract

Mortality of Atlantic salmon alevins in solutions containing Al and dissolved organic anions (both synthetic and natural) was correlated with Al accumulation in alevin tissues. Both mortality and accumulation could be related to the concentration differences between Al and organic anions. Mortality and body accumulation of Al both increased dramatically as total Al concentrations increasingly exceeded organic anion concentrations. Alevin growth and yolk utilization were both less rapid at inorganic monomeric Al concentrations exceeding 2 μM (50 μg L-1). The acidic fractions of dissolved organic matter (DOM) are more effective in protecting alevins against Al toxicity than are the neutral and basic fractions. Ambient inorganic monomeric Al is probably not toxic to salmon alevins in acidic Nova Scotian streams, even during snow-melt.