长江口南部赤潮区春季表层沉积物中色素组成、含量与分布状况

Pigment composition,content and distribution in surface sediment of the red-tide zone south to the Changjiang River estuary in spring

为剖析长江口邻近海域春季硅藻藻华后期藻类沉降与底层水体缺氧现象之间的关系,作者于2011年春季,在长江口南部赤潮区采集了表层沉积物样品,并通过高效液相色谱法(HPLC),对浮游植物色素进行了分析。结果表明,硅藻藻华发生后,表层沉积物中叶绿素a(Chl a)、岩藻黄素(Fuco)和19’-丁酰氧基岩藻黄素(But-Fuco)含量有显著增加,高值区主要分布在调查海域东南侧50 m等深线外侧,与底层低氧水体分布区基本吻合。因此,硅藻藻华后沉降的藻类对于该海域夏季缺氧区的形成应具有一定作用,其具体过程和机制仍有待于研究。

To reveal the relationship between microalgae deposition and bottom-water hypoxia in the red-tide zone of the Changjiang River estuary and the adjacent coastal waters, surface sediment samples were collected in spring of 2011, and phytoplankton pigments in surface sediment were analyzed with high performance liquid chromatography （HPLC）. It is found that content of Chlorophyll a （Chl a）, fucoxanthin （Fuco） and 19＇-butanoy-loxyfucoxanthin （But-Fuco） in surface sediment increased significantly after the bloom of diatoms. The region with high concentration of Chl a, Fuco and But-Fuco in surface sediment distributed mainly in the southeastern part of the investigation area, similar to the area with low level of dissolved oxygen in seawater at the bottom. It is concluded that deposited algae after the diatom bloom is important for the formation of summer hypoxic zone in this region. However, detailed processes and mechanisms still need further studies in the future.