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Effects of chronic chlorine exposure on litter processing in outdoor experimental streams
Author(s) -
NEWMAN RAYMOND M.,
PERRY JAMES A.,
TAM ERIC,
CRAWFORD RONALD L.
Publication year - 1987
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1987.tb01327.x
Subject(s) - streams , litter , riffle , plant litter , chlorine , environmental chemistry , zoology , chemistry , decomposition , ecology , environmental science , biology , ecosystem , computer network , organic chemistry , computer science
SUMMARY 1. 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 μg l −1 Total Residual Chlorine (TRC), one stream at 64 μgl 1 , and one stream at 230μg l −1 . Two control streams were not dosed; upstream riffles of each stream served as instream controls. 2. 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. 3. A third experiment, conducted in medium and high dose streams, indicated that high dose chlorine exposure reduced litter decomposition rates significantly, and reduced microbial colonization, microbial electron transport system activity, and microbial litter decomposition after 4 days but not after 11 days of exposure. The number of amphipod shredders colonizing litter bags was also reduced significantly with high chlorine dose. 4. A fourth experiment, after dosing was terminated, provided direct evidence that amphipod shredders were important in facilitating litter decomposition: litter bags stocked with amphipods had significantly higher decomposition rates than bags which excluded shredders. 5. Overall results indicate that the high dose (c. 230 μgl −1 TRC) of chlorine reduced litter processing rates partly by reducing initial microbial conditioning, but primarily by reducing the colonization of amphipod shredders.