东海两种赤潮生物种间竞争的围隔实验

1998年5月和2002年5月在东海赤潮高发区进行了两次添加营养盐诱发赤潮的围隔实验，结果表明，1998年5月实验开始时，具齿原甲藻和中肋骨条藻分别占群落总量的85％和11％，对照围隔中，具齿原甲藻一直处于优势，高峰时所占比例接近99％．加磷围隔中，中肋骨条藻显示出很强的竞争能力，第五天的数量与具齿原甲藻相等．2002年5月用4个围隔装置进行实验，在不同营养状况下两个种的增殖速率不同，营养盐浓度高的围隔中，中肋骨条藻的增殖速率比具齿原甲藻快得多，在营养盐限制条件下，具齿原甲藻比中肋骨条藻存活的要好。表明在营养盐丰富情况下，中肋骨条藻以其快速的繁殖在竞争中取得优势地位，导致中肋骨条藻形成的赤潮持续时间较短，消亡也快，而具齿原甲藻赤潮形成期较长，但在营养盐很低的情况下，还能维持较长时问．

Mesocosm experiment on competition between two HAB species in East China Sea

Skeletonema costatum and Prorocentrum dentatum are the two common HAB species in East China Sea, and Prorocentrum is more responsible for most HAB events in Spring since late 90's. The HAB caused by Skeletonema usually occurs from June to August. However, these two species will not bloom at the same time. Two mesocosm experiments were conducted in East China Sea in May 1998 and May 2002. In the experiment of May 1998, the cell number of Prorocentrum dentatum and Skeletonema costatum accounted for about 85% and 11% of total cell number of phytoplankton, respectively at the beginning of the experiment. In control mesocosm, Prorocentrum dentatum dominated the community during the whole experiment. In phosphate-enriched mesocosm, however, Skeletonema costatum showed a high competition capability. In May 2002, there were 4 bags in the mesocosm experiment. At the beginning of the experiment, the cell number of Prorocentrum dentatum accounted for 55-66% of the total, and that of Skeletonema costatum accounted for 32-42%. During the experiment, the growth of Skeletonema costatum was faster than that of Prorocentrum dentatum. On the 2nd day, the cell number of Skeletonema costatum exceeded that of Prorocentrum dentatum. It showed that under high nutrients conditions, Skeletonema costatum grew better than Prorocentrum dentatum, but under nutrients-limited conditions, Prorocentrum dentatum could survival better than Skeletonema costatum.