Effects of Chronic Chlorine Exposure on Litter Processing in Outdoor Experimental Streams

摘要

The effects of chlorine on litter (Potamogeton crispus L.) processing were examined using six outdoor experimental streams. Downstream portions of two streams were dosed at c. 10 microgram/l Total Residual Chlorine (TRC), another stream at 64 micrograms/l, and another stream at 230 micrograms/l. Two control streams were not dosed; upstream riffles of each stream served as instream controls. Two 35 day litter breakdown (per cent AFDW remaining) experiments indicated significantly lower decay rates in the high dose riffle. No other concentration of chlorine significantly affected decay rate. Overall results indicate that the high dose (c. 230 micrograms/l TRC) of chlorine reduced litter processing rates partly by reducing initial microbial conditioning, but primarily by reducing the colonization of amphipod shredders.