Daily monitor for the chlorophyll a and dissolved organic carbon (DOC) was carried during the spring phytoplankton bloom period (22 Feb. -28 Apr., 2005 The aim of this study was to research the kinetic characteristic of DOC during tile spring phytoplankton bloom. 300-600mL of water sample was filtered by the mico-filter (0.8 mu m) for chlorophyll a determination in the sampling boat using a hand held vacuum pump. And 60mL water sample was passed through a 25-mm diameter pre-ashed GF/F filters (450 degrees C 4hr) for DOC determination. The DOC was measured using the NPOC methods using total organic carbon analyzer (Shimadzu, TOC-V). The data of chlorophyll a showed the concentration of chlorophyll a was increased with the lapse of time, and phytoplankton bloom was observed twice. The first bloom standing a short period, and the second bloom standing a long period. The tendency of the concentration of DOC was similar to the chlorophyll a. Regression analysis showed that the concentration of DOC could explain 62% of the variability in chlorophyll a concentration in the whole monitoring period (R-2 = 0.62). Considering the rules of the spring bloom, two stages of spring bloom were divided according the dynamics of the concentration of chlorophyll a: the first stage was ranged from Feb., 23 to Mar., 28., the second stage was ranged from 29 Mar., to Apr., 28. Regression analysis for the relationships between DOC and chlorophyll a at different bloom stages was carried out individually. The result showed that the DOC could explain 72% variability in chlorophyll a concentration at the first bloom stage (R-2 = 0.72), and it could only explain 30% variability in the chlorophyll a concentration at the second bloom stage, According to the main source of the DOC in the natural water body, it can be deduced that the major contribute of DOC may be produced by the phytoplankton photosynthesis in the first bloom period and the major contribution of DOC may be produced by the decomposing of died algae in the second bloom period.
Ye Lin; Han Xin-Qin; Cai Qing-Hu (email@example.com).Kinetic study of the dissolved organic carbon in the Xiangxi Bay, three gorge reservoir region during the spring bloom period,Acta Hydrobiologica Sinica,2006,30(1):80-83