Distribution of sediment chloroplastic pigments in the Southern Yellow Sea, China

The distribution of sediment chloroplastic pigments (Chl-a, i.e. chlorophyll a and Pha-a, i.e. phaeophorbide a) in the Southern Yellow Sea of China was studied. Samples were collected from four cruises in January and June 2003, and January and June 2004. The results show that the vertical distribution of Chl-a and Pha-a in the sediment layers 0–2cm, 2–5cm and 5–8cm, follows a stable ratio, 5:3:2. The average ratio of Pha-a to Chl-a in sediment is 2.83. Spearman 2-tailed rank correlation analysis shows that Chl-a and Pha-a contents in each sediment layer have a highly significant correlation. The average contents of Chl-a and Pha-a in the sediment of the 0–8cm layer in the investigated area are 0.31–0.47µgg−1 and 1.28–1.40 µgg−1 sediment (dry weight), respectively. The average Chl-a and Pha-a contents in sediment are higher in summer than in winter. ANOVA analysis shows that there is a highly significant variation among the Chl-a contents (P=0.002>0.01) of the four cruies, but this is not true for the case of Pha-a content (P=0.766>0.05). The average Chl-a and Pha-a contents in the 2 sediment layers (0–2cm and 2–5cm) have significant or highly significant correlations with organic matter (OM), median diameter (Mdo), silt plus clay percentage in the January 2003 cruise. In the June 2003 cruise, the average Chl-a content in the 3 sediment layers (0–2cm, 2–5cm, and 5–8cm) has a significant correlation with meiofauna biomass, and Pha-a content has highly significant correlations with water depth, bottom water temperature, OM and Mdo. The contents of Chl-a and Pha-a are lower than those in estuaries and intertidal areas, but close to those in the same area studied previously.