南黄海绿潮暴发早期与末期显微繁殖体分布及种类组成研究

Quantitative distribution properties and species composition of Ulva microscopic propagules in the South Yellow Sea

调查了2012年4月、8月和2013年4月、8月两年4个时期的南黄海绿潮藻显微繁殖体分布与种类组成。研究绿潮暴发早期（4月份）,南黄海已有显微繁殖体广泛分布,高值区主要分布于如东、大丰近岸海域,2012年4月大丰海域密度最高可达1 312ind/L,2013年4月如东海域密度达到884 ind/L;黄海绿潮暴发末期（8月份）,高值区随大面积绿潮藻向北转移,随着如东和大丰海区漂浮绿潮藻消失,显微繁殖体的数量降低至较低水平,2012年和2013年8月密度范围分别为0-38 ind/L和0-28 ind/L。2012年和2013年4月显微繁殖体由曲浒苔（Ulva flexuosa）、浒苔（Ulva prolifera）和缘管浒苔（Ulva linza）组成,8月由曲浒苔（Ulva flexuosa）和浒苔（Ulva prolifera）组成。4月份显微繁殖体在如东、大丰海区高密度分布表明绿潮发生前期南黄海绿潮藻种质库的存在,大量显微繁殖体可以在春末海区温度回升时期迅速萌发,成为早期绿潮形成的贡献者之一。

The quantitative distribution properties and species composition of Ulva microscopic propagules in the South Yellow Sea during April, August in 2012 and 2013 were investigated. During the earlier stage （April） of the green tide blooms, Ulva microscopic propagules widely existed in the South Yellow Sea, and mainly distributed at the coast of Rudong and Dafeng sea area. The density was 1312 ind/L at the coast of Dafeng sea area in April 2012 and 884 ind/L at the coast of Rudong sea area in April 2013. With the floating green algae gradually disappeared, the number of Ulva microscopic propagules at the coast of Rudong and Dafeng sea area reduced to a low level, and the density was in range of 0 - 38 ind/L and 0 - 28 ind/L in August 2012 and 2013, respectively. Ulva microscopic propagules were composed by Ulva flexuosa, Ulva prolifera and Ulva linza in April 2012 and 2013, while Ulva flexuosa and Ulva prolifera in August 2012 and 2013. Seed bank may exist at the earlier stage of the green algae blooms due to Ulva microscopic propagules widely existing at the coast of Rudong and Dafeng sea area in April. Large amounts of microscopic propagules would rapidly germinate when the surface temperature increased during the period of April - May, which was partly contributed to the biomass of early green algae blooms.