Based on the investigations oil primary productivity and related factors at one fixed stations in Guanzhuangping Bay of Xiangxi River from February to April 2005, this paper studied the temporal and spatial distribution of chlorophyll a, primary productivity, and their relationships with change of ray radiation intensity in water. Although the results showed that there were obvious same periodic change appeared 5 peak value and were 7-10 days interval averagely, not synchronization in chlorophyll a and primary productivity in the each layer of water. Tile true light layer depth that was lied intervenient the lake and ocean, was as 10m water depth or so at Guanzhuagping Bay, the light compensates to order for the 4-5m water depth. The high values of primary productivity were confirmed in 0.5 underwater,and one of chlorophyll a content was 2m water depth. The vertical change of water temperature showed that the obvious difference was recorded at latter clays, There were significant positive correlation between increment daily average temperature(Delta T.d(-1)) and average gross primary productivity, net primary productivity in every water layer.The investigation also made Lis know more about the unique characteristics of the river ecosystem Is primary productivity, differ from other types water body in Guanzhuangping Bay of Xiangxi River in Sanxia reservoir. With the strengthen of the strong light, the primary productivity of the initial stage(bottom floor) increases with small extent; when the light strengthen rises to over 50 (mu mol/m(2).s) tile increasing extent of tile primary productivity was enlarged. This changing trend was different from that of lakes. The result of 17,roup data measured before April 10 showed that the temperature in different water layer does not have significant difference. So, in the low water temperature season, the perpendicularity of the temperature has minor influence oil tile primary productivity. Because of "enwraping effect" of tile existing chlorophyll,there is no significant relationship between the perpendicularity of chlorophyll and the primary productivity. The chlorophyll density has the same periodic as the variety of each layer of water, both including 5 peak value. The each average period was about 7-10 d; The entry-level produces also have the periodic changes, with the times of existing crests same as that of chlorophyll, yet did not exit at tile same time. However, based oil the acquired data, we can't clearly analyze tile Causes of the differences between the varieties of time arid the perpendicularity of the chlorophyll and primary producing.
Shao Xiao-Yang; Xu Yiao-Yang; Han Xin-Qin; Cai Qing-Hua (email@example.com).The distribution of chlorophyll a content and primary productivity in Guanzhuangping Bay of Xiangxi River,Acta Hydrobiologica Sinica,2006,30(1):95-100