初夏南黄海浮游动物功能群丰度年际变化

INTERANNUAL CHANGES IN THE ABUNDANCE OF ZOOPLANKTON FUNCTIONAL GROUPS IN THE SOUTHERN YELLOW SEA IN EARLY SUMMER

利用1959年和2000—2009年6月份在南黄海海域进行的7个航次海洋调查采样样品,并结合同步温盐资料及海温长期变化数据,研究了不同浮游动物功能群丰度的年际变化。结果表明:大型甲壳类和毛颚类功能群丰度高且波动幅度较大,在1959年和2000—2009年两个时期无明显差异,最低值分别出现在2003年和2000年;而中华哲水蚤为优势种的大型桡足类功能群丰度在2000—2009年显著高于1959年,波动范围分别在2035—24500和912—1330ind/m2之间;小型水母和海樽类功能群丰度一般较低,但是在2007年出现暴发式增加,平均丰度分别是其它年份中最高平均丰度的4.8倍和88.5倍。大型甲壳类和毛颚类分别在东部冷水团区和中部锋面区波动幅度最大,小型水母和海樽类则是在西部浅水区波动幅度最大。分析认为桡足类丰度增加与营养盐浓度升高和鱼类过度捕捞有关,而胶质生物种群剧烈波动与气候变化引起的环境变异相关。

Zooplankton samples were collected from seven oceanographic censuses in the southern Yellow Sea in June in 1959 and 2000--2009. The interannual changes in abundance of different zooplankton functional groups were studied with simultaneously measured temperature-salinity data and long-term change data of seawater temperature. The results show that both giant crustaceans and chaetognaths had high abundance and fluctuated remarkably; both the abundance was similar between 1959 and 2000--2009, of which the lowest abundance occurred in 2003 and 2000, respectively. The abundance of large copepods, dominated by Calanus sinicus, was significantly higher in 2000--2009 than that in 1959, and the fluctuation ranges were 2035--24500 and 912--1330 ind/m2 in the two periods, respectively. Small jellyfish and salps usually presented low abundance, but both increased dramatically in 2007 for being 4.8-fold and 88.5-fold, respectively, of the highest mean abundance in other years. Giant crustaceans and chaetognaths varied widely in the Yellow Sea Cold Water Mass region and tidal front region, respectively, while small jellyfish and salps fluctuated widely in the western shallow region. We believe that the increased copepod abundance was resulted from increased nutrition and over-fishing, while the dramatic fluctuation of gelatinous zooplankton was due to environmental variation under global climate change.