G. Van Urk

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This survey of the macrobenthos of the River IJssel, a branch of the River Rhine, was conducted in 1973, 1975, 1976 and 1977. The water quality was poor in 1973 and 1976 and relatively good in 1975 and 1977. The numbers of macroinvertebrate species and numbers of individuals in the stone samples taken from the jetties were lowest in 1976 and highest in(More)
Exposure of 4–5 day oldDaphnia hyalina to temperatures of 32° C and higher caused substantial mortality when the exposure time was an hour or more. The tolerance ofBosmina sp. to temperature shocks appears to be about that ofD. hyalina. Naupllus larvae ofCyclops sp. were much more tolerant. Survival and reproduction ofD. hyalina at high temperatures were(More)
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