Abstract: Based on the ecological investigation data in September and October 2007, the status of the marine ecological environment of Nanri Archipelago, Fujian Province in summer was diagnosed and assessed from the aspects of sea water quality, nutrient structure and levels, and biodiversity. The comprehensive quality index method was used for the assessment of the marine ecological environment, and the rationality of the assessment obtained from different indices was also discussed. The sea water pH, dissolved oxygen (DO), chemical oxygen demand (COD) , and Pb, Cd, Hg, and As concentrations were all within the limit values of the GradeⅡstandard of Sea Water Quality Standard (GB 3097-1997), while the phosphate concentration at 71% stations, inorganic nitrogen at 14% stations, and oil concentration at 7% stations were all above the GradeⅡstandard of Sea Water Quality Standard. Overall, the seawater quality was of better grade, nutrient structure was characterized by N-limited, most of the sea water was at a state of eutrophication, and the diversity index of plankton was at mildly polluted or unpolluted level. The comprehensive quality index indicated that the seawater quality of the Nanri Archipelago was relatively fine. There existed definite differences in the assessment results by using different diagnosis methods, and hence, a relatively objective assessment about marine environmental quality and health status could only be made when the chemical and biological indicators were comprehensively used.

Key words: marine ecological environment, health diagnosis, quality assessment, Nanri Archipelago water area