A study of distribution variation of chlorophyll a and regulatory effects of environmental factors in the Yellow Sea nearshore area of Shandong province

摘要

The concentration of Chlorophyll a and the values of environmental factors, were determined in the water collected from Yellow Sea nearshore area of Shandong province between August 2006 and October 2007. Results indicated that annually averaged concentration of chlorophyll a was 4.26 mg/m3 in the investigated sea areas, meanwhile there was a chlorophyll maximum in summer and a secondary maximum in spring. In general, the concentration of chlorophyll a gradually decreased from shore to offshore in spring, summer, winter, while opposite in autumn, and high (low) value areas of chlorophyll a horizontal distribution were alien within different seasons. The spatial-temporal distribution of environmental factors showed high heterogeneity(except pH), and the environmental factors exerted regulatory effects on the distribution of chlorophyll a in different extent. According to PCA and Bivariate correlation analysis, the most critical regulatory factor which determined the distribution of chlorophyll a was nutrients, especially nitrogen, next came phosphorus, silicon. The regulatory effects of dissolved oxygen and temperature was antagonistic with each other, while that of pH and total organic carbon was weak.