| 摘要: |
| 中小型桡足类是海洋食物网中重要的中间环节，在碳循环里细菌碳和藻类碳向高营养级转化的过程中扮演重要角色。本文通过分析2013年3-4月、6-7月、9-10月和11-12月南沙群岛海域（111°30'E-112°30'E，4°30'N-11°30'N）的生态环境调查数据，对长腹剑水蚤属（Oithona）的种类组成、数量分布及其与环境因子的关系进行了研究。结果表明：（1）南沙群岛海域共出现长腹剑水蚤15种（包括1个未定种），其中线长腹水蚤（Oithona linearis）、粗长腹剑水蚤（O.robusta）和长刺长腹剑水蚤（O.longispina）为南沙群岛海域首次记录，长腹剑水蚤属种类组成沿水深变化的现象较为明显，该属虽然在南沙群岛海域广泛分布，但单种的出现频率较低，其种类出现的季节性较强；（2）南沙群岛海域的长腹剑水蚤可以划分为常见广布组群Ⅰ和低频组群Ⅱ；（3）长腹剑水蚤年均栖息密度为30ind./m3，季节变化呈单峰型，秋季最高、冬季最低，高数量区主要出现在受南沙西部沿岸流和东部沿岸流影响的近岸海域；（4）在0-750m水深范围内，长腹剑水蚤数量沿水深梯度的垂直变化明显，呈现由浅至深数量明显减少的趋势，长腹剑水蚤主要集中分布在0-75m的水层中，75-500m数量急剧降低至最低后，在500-750m基本维持不变；（5）GAM分析表明，纬度、海水温度、盐度和叶绿素a浓度对长腹剑水蚤数量均有影响，以纬度的影响最为显著，其中长腹剑水蚤属最适温度为28.6-29.2℃，最适盐度为32.6-33.2，最适叶绿素a浓度为5-10μg/L；（6）长腹剑水蚤属更适栖息于低温和低盐，且受沿岸流影响的环境中。因此，其数量分布的季节变化与季风驱动的沿岸流势力强弱密切相关。 |
| 关键词: 浮游动物 长腹剑水蚤 种类组成 密度分布 环境因子 广义可加模型 南沙群岛 南海 |
| DOI：10.11693/hyhz20160700143 |
| 分类号: |
| 基金项目:国家自然科学基金项目，41406188号；国家科技支撑计划课题，2013BAD13B06号；广东省科技计划项目，2014A020217011号；农业部财政重大专项，NFZX2013号。 |
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| ASSEMBLAGE AND ABUNDANCE OF OITHONA AND ENVIRONMENTAL FACTORS IN NANSHA ISLANDS WATERS, SOUTH CHINA SEA |
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DU Fei-Yan1,2,3, WANG Liang-Gen1,2,3, WANG Xue-Hui1,2,3, NING Jia-Jia1,2,3, GU Yang-Guang1,2,3, LI Ya-Fang1,2,3
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1.Guangdong Provincial Key Laboratory of Fishery Ecology and Environment;2.Scientific Observing and Experimental Station of South China Sea Fishery Resources and Environments, Ministry of Agriculture;3.South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
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| Abstract: |
| Meso-small copepods are important links in marine food webs,serving as important carbon careers from bacteria and phytoplankton to marine carnivores.We analyzed the assemblages and abundance of genera Oithona using net and environmental data obtained in 2013,and evaluate the environmental effect in the generalized additive model.Fifteen Oithona species were identified,including an unknown species,and three first recorded species,i.e.,O.linearis,O.robusta,and O.longispina.The Oithona assemblages changed in water depth and in season,and could be divided into a group in wide distribution and a group in low occurrence frequency.The abundance increased from winter to autumn,and was higher in the areas affected by coastal current.The annual abundance decreased from surface to 750m in depth in average of 30 ind./m3,and most abundant from surface to 75m.The abundance showed a clear down trend from 75m to 500m,and became low and uniform from 500m to 750m.Temperature,salinity,chlorophyll a concentration,and latitude were the major influential factors.The most favorable temperature,salinity and chlorophyll a concentration for Oithona living were 28.6-29.2℃,32.6-33.2,and 5-10μg/L,respectively.In addition,Oithona distribution was highly related with coastal current that was relatively cooler and less salty.Overall,the seasonal variation in the abundance was controlled by coastal current driven by monsoon. |
| Key words: zooplankton Oithona species composition density distribution environmental factors generalized additive model (GAM) Nansha Islands South China Sea |
