Effects of sediment dredging on water quality and zooplankton communitystructure in a shallow of eutrophic lake
Shiyang Zhang , Qiaohong Zhou , Dong Xu , Jidong Lin , Shuiping Cheng , Zhenbin Wu
DOI:
Received May 12, 2009,Revised June 18, 2009, Accepted , Available online
Volume 22,2010,Pages 218-224
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Effects of suction dredging on water quality and zooplankton community structure in a shallow of eutrophic lake, were evaluated.
The results showed that a decreasing trend for levels of phosphorus, organic matter, total suspended solids, Chlorophyll a and Secchi
transparency in the water column was found, while levels of water depth, electrical conductivity, total dissolved solids and NO3??-N
concentration increased markedly post-dredging. The e ects of dredging on dissolved oxygen, pH value and temperature were almost
negligible. The zooplankton community structure responded rapidly to the environmental changes caused mainly by dredging. As a
result, the abundance of rotifers decreased, while the density of zooplanktonic crustaceans increased markedly. The representative taxa
were Brachionus angularis, B. budapestinensis, B. diversicornis, Synchaeta spp. and Neodiaptomus schmackeri. A distinct relationship
between zooplankton taxa composition and their environment, unraveled by a redundancy analysis, indicating that the measured
environment contributed to the variations in the zooplankton community structure to some extent. The first four synthetic environmental
variables explained 51.7% of the taxonomic structure. Therefore, with the reduction of internal nutrient load and a shift in dominance
by less eutrophic species, it inferred that dredging might be one of e ective measures for environmental improvements of such lakes.
