草鱼精养池塘养殖水体富营养状况及藻相特征分析与评价

水质的营养程度对水产养殖的健康发展有着极其重要的作用,使用综合营养状态指数法可以对养殖水体的营养状况作出准确评价。对广州诚一水产养殖有限公司试验水域营养及藻相特征进行分析和评价,得出水体富营养化程度大部分处于中度富营养状态,少数处于轻度富营养状态,极少数处于中营养状态;藻类丰度中绿藻门最高(69.95%),其次是蓝藻门(20.03%),然后依次是硅藻门(1.73%)、裸藻门(8.29%)。

廉州湾近岸的海水理化要素含量的变化特征

根据2003年7月至2004年6月廉州湾近岸水质监测资料,以DIN、PO4-P、COD为富营养化评价指标,分析廉州湾近岸海水理化要素测值的变化特征。结果表明,廉州湾内河口区海水富营养化程度分布较高,湾口区相对较低;水温季节变化不大,盐度春夏季低秋冬高,pH值季节变化不明显,COD夏季明显高于春季,活性硅酸盐冬季较低,DIN春季高于冬季,PO4-P春季大于冬季,廉州湾沿岸水质变化的主要原因与河口径流、沿岸河水、水产养殖排放物有关。

Relative abundance of biotic communities of plankton and zoobenthos in three ox-bow lakes of Eastern India

We made comparative studies of three tropical ox-bow lakes in India with different trophic states.The species number of zooplanktons was negatively correlated with the degree of water eutrophication,and lakes of similar trophic status had higher similarity of species.The most significant differences of species composition were observed with rotifers and zoobenthos.The density and biomass of phytoplankton,rotifers,oligochaetes and chironomids tended to increase with increasing nutrients.We observed a significant difference of dominant species in different waters,especially the eutrophic lake,which was dominated by a few species of oligochaetes.The abundance of Tanypus bilobatus showed a highly significant correlation with the degree of eutrophication.Rotifers and zoobenthos showed considerably lower biodiversity in the eutrophic lake.