| This paper introduces the work of “Environmental Impact Assessment (Phase III) in Yantai Harbor” in the sea area of Zhifu Bay, Yantai, in 1993. The samples of benthos were collected using an HNM mud dredger and analyzed in laboratory. 87 benthos species were obtained and the biomass and density of these species were derived. 10 representative species (Lumbrineris latreilli, Lumbrineris longifolia, Tharyx multifilis, Cirriformia tentaculats, Sabellidae spp., Ophiura kinbergi, Fulvia mutica, Macoma praetexta, Mya arenaria, Corophium sp.) of Crustacean, Mollusca, Echinoderm, Polychaeta and 12 benthic environmental variables (Eh, Hg, Cu, Pb, Zn, Cd, Cr, Fe, Mn, oil, organic matter, sulfide) were considered in the study of the relationship between the benthos and environmental factors. The stepwise regression equation of the typical species and their habitat environment was established. Through these analysis, the principal environmental factors controlling the density of some species were identified. The contents of heavy metals and oil in the body of the three species of Mollusca were also analyzed and the concentration factors were calculated. At the same time, the indicator organisms of environmental pollution were discussed. Compared to the investigation data in 1986 about the content of the pollutant and the constitution of the benthos, we have the following results:
(1) The content of the benthic environmental factors in Zhifu Bay increased dramatically in recent years with the trend of spreading from the surroundings to the centre of the bay. In particular, the bottom of the harbor pool has been polluted heavily, which is shown by the constitution of the benthos.
(2) The structure of the benthos community has been changed. In 1983, the representative organisms were some species of Echinoderm such as Asterias vollestoni, Asterina pectinifera, Luidia quinaris and the clean water indicator species Temnoleurus toreumatice. However, in 1993, the representative species changed to some pollutant-resistant species of Polychaeta such as Tharyx multifilism, Cirriformia tentaculata, L. latreilli and Lumbrineris longifolia. Temnoleums toreumatic disappeared, indicating that the constitution of the benthos had been changed from the non pollutant resistant species of Echinpdermata to the pollutant-resistant species of Polycharta.
(3) A quantitative relationship between the typical species and their habitat environment and the distribution of these typical species indicate that the content of Zn, Mn, Hg, organic matter have an apparent effect on the density of Polychaeta and so do the content of Hg, Cu, Pb, Cd, organic matter on the density of crustacean.
(4) The content of heavy metals and oil in Mya arenaria, Chlamys farreri, Mytilus edulis and many concentration factors have been obtained. Tharyx multifilis Moore, Corophium sp., Macoma praetexta appear to act as pollution indicator organisms, especially Macoma praetexta for oil pollution. The results show that Cirriforima tentaculate is more resistant to pollutants than Capitella capitata does, this differs from previous conclusions.
The change in environmental factors in Zhifu Bay results in an acute of chronic toxic effect on the organisms; thus, the number of pollutant-resistant species increase, resulting in the succession of the community. This process reflects the adaption of the organisms to their environment. This may become an important aspect in the study of biodiversity and conservation biology. |
