东江水库对耒水中下游原生动物的影响

为评价东江水库建成对耒水中下游水生生物的影响，１９９３年作者对东江水库坝下耒水中下游原生动物进行了两次调查。结果四个断面共发现原生动物８４种，其中丰水季（８月）５９种，多于枯水季（１０月底）的４６种，但丰水季数量（４３５个／Ｌ）和生物量（０．０３６ｍｇ／Ｌ）都低于枯水季（３．２４４个／Ｌ，０．３３５ｍｇ／Ｌ）；多样性指数与种种类数一样，多是丰水季大于枯水季。建库后，从中游到下游原生动物种类数，数量

EFFECTS OF DONGJIANG RESERVOIR ON PROTOZOA IN THE MIDDLE AND LOWER REACHES OF THE LEISHUI RIVER

In order to evaluate effects of Dongjiang Reservoir on plankton in the middle and lower reaches of the Leishui River, the protozoa was investigated in flood season (August)and dry season(end of October) in 1993 . 84 species of protozoa were found in four sections. The composition of the protozoa was more complex in flood season than in dry season(59/46), but abundance (435 ind./L) and biomass(0.036 mg/L) were lower in flood season than in dry season(3 244 ind./L, 0.335 mg/L). Like the species composition, the diversity index was bigger in flood season than in dry season. With the completion of reservoir dam, there occurs a increase tendency in species, abundance and diversity index of protozoa from the middle to lower reaches of the Leishui River. Less species and lower standingcrop of protozoa in the section near reservoir dam were related with lower water temperature. Some other factors of effecting protozoa were discussed in the paper.