PRIMARY STUDY OF ASSEMBLAGE CHARACTERISTICS OF GRAND BENTHOS IN THE MODERN ZHUJIANG RIVER SUBAQUATIC DELTA
Zhou Qingwei Zhang Guangwei (Institute of Marine Geology, Ministry of Geology & Mineral Resources, Qingdao, China 266071) Ma Xiutong (Institute of Oceanography, Academia Sinica, Qingdao, China,266071)
This paper was based upon benthos data obtained by 2nd Marine Geological Investigation Brigade and Institute of Marine Geology in their joint comprehensive survey in modern environment of the Zhujiang River Delta. Through examination, grand benthos in this area have 67 genera and 130 more species,mainly consisting of bivalvia, gastropoda and balanus, and belonging to India-West Pacific tropical and subtropical types. The overwhelming majority are nearshore brackishsaline water species, living in intertidal to shallow water area or in brackish water of a river mouth. In the respects of species composition and ecological distribution, this paper has made a systematic analysis for biota in 4 primary environments (delta plain, delta front, estuary and shallow shelf), and also approached the effects of environmental factors such as temperature, salinity, water depth, bottom material, and hydrologic condition etc. on benthos. Through studies, we know that ecological distributions of benthos correspond with environments in this area and also can be divided into 4 areas and 7 subareas of biological groups. The species have a close relationship with salinity, water depth and sedimentation rate, that is to say, species are monotonous and in small number near river mouth, increase gradually with distance from river mouth, and become aboundant in shallow sea area.