Abstract:Marine environment is a grey system. Applying the grey clustering method to assessing the eutrophication of marine environment is to establish a comparatively perfect model for marine environment evaluation and give a sound assessment for the quality of marine environment, thus, providing evidence for marine environment management. Referring to Chinese Seawater Quality Standard (GB3097-1997) and the characteristics of seawater eutrophication, selecting PO3-4-P, DIN, DO, COD and Chl-a as evaluation indexes, and classifying seawater eutrophication into three levels, then using the whitenization weight function to describe its grading sideling and determine the clustering weights, coefficients and their grades of the corresponding indices in the grey system, a comprehensive evaluation model was established.Taking Jiaozhou Bay as the subject, through the analysis of the data in Jiaozhou Bay in May and August of 2009, the result showed that the eastern Jiaozhou Bay was in the state of eutrophication, the western and northern water was in the state of medium-level nutrient, and the center and mouth of the bay was oligotrophic. The state of water quality was closely related to the river runoff, industrial and agricultural discharge, domestic sewage, aquaculture wastewater, water exchange rate and the water depth. The eutrophication state evaluated by the grey clustering method can reflect the real situation of Jiaozhou Bay, indicating that the assessment of seawater eutrophication by the grey clustering method is feasible.
