Original paper

Uranium contaminated water does not affect microbial activity but decreases feeding by the shredder Sericostoma vittatum

Gonçalves, Ana Lúcia; Lírio, Ana Virgínia; Pratas, João; Canhoto, Cristina

Abstract

Streams polluted with uranium mine drainages are abundant in Central Portugal with over 50 abandoned mines. We investigated the effect of stream water contaminated with uranium mine effluents on oak leaf (Quercus robur) decomposition and associated decomposer communities and its impacts on the feeding ecology of larva of the caddisfly shredder Sericostoma vittatum. Leaf mass loss, toughness and fungal biomass in oak leaves did not differ between reference and contaminated water. However, microbial respiration was significantly higher in leaves exposed to contaminated waters. Shredders preferentially consumed leaves exposed to reference rather than contaminated stream water. Although 100% survival was observed in both treatments, consumption and relative growth rate decreased to half in larvae provided with leaves incubated in contaminated water. This may be due to less palatable leaf-microbial assemblages and/or to higher contents of metals accumulated by the leaves. We hypothesize that uranium mine drainages impair stream ecosystem function through their effects on shredders rather than on microbial processing.

Keywords

leaf decompositionmine drainagesshredder behavioururanium mine drainagesericostoma vittatum