2009年秋季旋沟藻赤潮爆发期间珠江口表层水体的环境特征

2009年秋季在珠江口海域爆发了一次大规模的双胞旋沟藻赤潮,影响面积高达300 km2。赤潮爆发期间,我们对珠江口水域的环境因子特征进行了调查。结果表明,调查期间珠江口西侧受径流的影响程度远高于东部,营养盐一般呈西高东低的水平分布格局,其中以NO3-N、DIN和SiO3-Si的差异最为明显。表层水体的DIN、PO4-P和SiO3-Si的平均浓度分别为31.64μmol/L、0.71μmol/L和46.3μmol/L。SiO3-Si和PO4-P的高值区主要位于洪奇门及以下的珠海沿岸,PO4-P的高值区主要位于洪奇门以上的水域,虎门附近S1站位的PO4-P浓度高达6.23μmol/L。高的营养盐输入、低的降雨量和严重的咸潮入侵应该是导致这次双胞旋沟藻赤潮爆发的重要诱因。

Environmental characteristics in surface water of the Zhujiang Estuary during the period of Cochlodinium blooms in fall,2009

A large-scale Cochlodinium geminatum red tide(> 300 km2) occurred in the Zhujiang Estuary in fall,2009.The environmental characteristics in the surface waters were investigated in the Zhujiang Estuary during the period of Cochlodinium blooms outbreak.The nutrients were more influenced in the west coast of Zhujiang Estuary by the run off of Zhujiang Estuary,and most of nutrient species showed a high value in this region.The average concentration of DIN,PO4-P and SiO3-Si were 31.64 μmol/L,0.71 μmol/L and 46.3 μmol/L,respectively.The NO3-N and SiO3-Si mainly were from the Hongqimen outlet and the coast of Zhuhai City.The PO4-P mainly was from the Humen outlet,which was high to 6.23 μmol/L in S1 nearby Humen outlet.The low precipitation,severe saline intrusion and heavy phosphorus should be responsible for the outbreak of Cochlodinium blooms.