黄河口水下三角洲及其邻近水域小型底栖动物的初步研究

PRELIMINARY STUDY ON THE ECOLOGY OF THE BENTHIC MEIOFAUNA IN THE HUANGHE RIVER ESTUARY AND ITS ADJACENT WATERS

本文是于1986年7—8月对黄河口水下三角洲及其邻近海域的调查结果。小型动物的平均密度为789.2±292.7个/10cm^2。自由生活的海洋线虫是数量最多的类群,占66.5％,平均密度为526.8±261.7个/10cm^2;桡足类和介形类的百分比组成和平均密度分别为16.9％和4.7％,131.0±73.1个/10cm^2和20.0±27.8个/10cm^2,与世界上同类水域小型动物数量的比较结果十分相近。小型动物类群组成随着远离水下三角洲水深的增大和沉积环境的改变,线虫优势减弱,而桡足类显著增加。根据小型动物类群组成的变化,大型动物的密度,生物量和平均每站种数,对研究海域进行的分区与自然分区基本相一致,即(1)黄河口水下三角洲,(2)莱州湾,(3)渤海中部,(4)渤海湾东南部。联系沉积环境对小型底栖动物的划分进行了讨论。

The benthic meiofauna (metazoa<0.5 mm) was quantitatively investigated in the Huanghe River estuary and its adjacent waters at 20 stations during the summer of 1986. Mean meiofaunal abundance amounted to 789±293 inds. /10 cm2. Free-living marine nematodes constituted 66.5% of the total, with the mean density of 527 + 262 inds./10 cm2, and were the most abundant organisms at all stations. Harpactioid copepods were second in overall abundance, constituting 16.7% of the total with the mean density of 131±73 inds/10 cm2. Ostracoda constituted the lowest percentage 4.7%, with 20±28 inds./10 cm2.The percentage of the numbers of nematodes decreased with depth and distance from the river mouth while the percentage of Copepoda increased. The change of the percentage of nematodes and copepods well reflected the change of sedimentary composition.Based on the results obtained, together with the data of their abundance, biomass and numbers of macrofauna species, the investigation area may be divided into subaqutic delta, the Lai-zhou Bay, the central part of Bohai and the southeast part of Bohai Bay. These areas are well coincident with natural zone. According to the depth and sedimentary environment (sedimentary rate and composition of sediment), the subdivision of the meicofauna is discussed.