西沙监控区浮游植物生态现状

The Ecological Status of Phytoplankton in Monitored Xisha Areas

2007年4月对中国西沙群岛的5个生态监控区,即永兴岛、石岛、西沙洲、赵述岛和北岛的浮游生物和水质进行采样调查。结果表明:5个生态监控区浮游植物的种类为50属117种,第1优势种为红海束毛藻(Trichodesmium erythraeum);浮游植物的平均密度为2.08×104ind/m3,范围为4.42×104～0.85×104ind/m3。多样性指数、丰富度指数一般,均匀度指数低。目前西沙生态监控区浮游植物没有受到人为输送含N、P和Si的化合物影响,P是浮游植物的主要限制因子。

The water and phytoplankton in 5 monitored Xisha areas,namely Yongxing Island,Shidao Island,Xisha Island,Zhaoshu Island and Beidao Island were sampled and analyzed in April,2007.The results showed there were 117 species algae,belonging to 50 genera in the areas.The dominant species was Trichodesmium erythraeum.The average density was 2.08×104 ind/m3,ranging from 4.42×104 ind/m3 to 0.85×104 ind/m3.The value of diversity index and richness were normal,but the value of uniformity was low.And the phytoplankton in the areas was not affected by chemical elements such as N,P and Si compounds brought by human being.P was the main limiting factor to phytoplankton in the areas.