Abstract:An in situ nutrient enrichment bioassay was conducted using surface lake water collected from six stations of Lake Taihu. The objective of the study was to investigate nutrient limitation of growth of phytoplankton, much of which was dominated by cyanobacteria, in different areas of the lake. The results showed that in Meiliang Bay (station 3), phytoplankton biomass (Chl a) increased significantly with combined addition of nitrogen (N) and phosphorus (P), with no significant effect from individual additions of N or P separately, suggesting that nutrient limitation of these two nutrients may be tightly coupled. In the river transition zone in the western area of the lake (station 10), and in Zhushan Bay (station 16) and Gonghu Bay (station 13#), chl a in the N aloneaddition treatments did not increase significantly compared to the initial chl a, but P addition treatments (both +P and +NP ) led to significantly higher chl a concentrations than the control, reflecting N-replete and P-deficient biomass in these three areas. In the eastern part of the lake (station 24), additions of N and P individually and together did not stimulate growth compared with the control, suggesting factors other than N and P may limit phytoplankton growth. Under conditions where N and P produced cells that were replete in these nutrients, phytoplankton growth rates in Meiliang Bay and the estuary zone in the western bank were highest (0.3d-1), suggesting growth potential is largest in these two zones. This may help to explain why there are severe cyanobacterial blooms in these zones. Phytoplankton growth rates were lower (0.11 d-1 and 0.15 d-1, respectively) under nutrient replete conditions in Gonghu Bay and Xukou Bay, and losses occurred with nutrient additions in the eastern part of the lake, suggesting phytoplankton growth potential is low in these zones.
许海, 秦伯强, 朱广伟. 太湖不同湖区夏季蓝藻生长的营养盐限制研究[J]. 中国环境科学, 2012, 32(12): 2230-2236.
XU Hai, QIN Bo-Qiang, ZHU Guang-Wei. Nutrient limitation of cyanobacterial growth in different regions of Lake Taihu in summer. CHINA ENVIRONMENTAL SCIENCECE, 2012, 32(12): 2230-2236.