海洋生态与环境科学重点实验室知识库

浮游动物在海洋生态系统中起着至关重要的枢纽作用，其对气候变化和海洋环流具有很好地指示作用。我国近海陆架宽广，作为北太平洋西部的边缘海，受太平洋西边界流的影响显著。邻近的西太平洋独特的地理环境和复杂的海流系统孕育了独特的生态系统，具有较高的生物多样性。因此，在该海域开展浮游动物的生态学研究具有重要意义。本文基于浮游动物图像扫描分析系统（ZooScan系统），利用浮游动物标准化生物量谱的方法，研究了我国黄海海域、东海海域以及北太平洋低纬度西边界流海域上层至深层（3000m）的浮游动物群落结构的时空变化，旨在为从中国近海到西太平洋的浮游动物群落结构大尺度的变化研究提供基础数据。
在黄海海域，利用2013年8月至9月采集的样品，基于ZooScan系统推算得到浮游动物混合样品的总体积生物量，所得结果与传统方法测量得到的总干重、总含碳量和总含氮量具有极显著的相关关系；并且，基于ZooScan技术得到的浮游动物体积生物量和类群信息，对南黄海夏季浮游动物群落划分的结果与历史研究的结果相一致，验证了ZooScan系统用于浮游动物混合样品中由体型参数估算生物量的可行性，为浮游动物群落结构的研究提供一种快速、可行的方法。
在此基础上，利用ZooScan技术开展了我国黄海、东海以及北太平洋低纬度西边界流海域上层至深层（3000m）浮游动物群落结构的研究。在黄海和东海，利用2014年秋季（10月至11月）获取的中型浮游生物网的样品，共鉴定浮游动物类群17个，包括桡足类（Copepoda）、磷虾类（Euphausiacea）、毛颚类（Chaetognatha）、水母类（Medusa）、被囊类（Tunicata）、介形类（Ostracoda）、端足类（Amphipoda）、腹足类（Gastropoda）、多毛类（Polychaeta）、仔稚鱼（Fish larvae）、无节幼体（Nauplius）、夜光虫（Noctiluca scintillans）、枝角类（Cladocera）、有孔虫（Foraminifera）、放射虫（Radiolaria）、鱼卵类（Fish eggs）和其它浮游动物等。浮游动物丰度的变化范围为571.4—65995.1 ind. m^-3，平均为6988.0±11008.1 ind. m^-3，其中，桡足类、夜光虫和被囊类是三大优势类群。浮游动物体积生物量的变化范围为62.7—13050.2 mm³ m^-3，平均为1468.3±2364.8 mm³ m^-3，其中，桡足类、水母类和毛颚类是三大优势类群。根据浮游动物标准化生物量谱的结果，黄海、东海的浮游动物可划分为四个群落：黄海群落、黄、东海交汇群落、东海近岸群落和东海陆架群落，其分布主要受到不同水团、海水温度、纬度等环境因子的影响。
黄海和东海海域四个群落标准化生物量谱的斜率均较−1平缓，说明我国黄海、东海海域的浮游动物群落具有相对较高的能量传递效率。浮游动物标准化生物量谱的斜率在黄海群落和黄、东海交汇群落均为−0.66，在东海近岸群落和东海陆架群落均为−0.72，说明黄海海域的浮游动物群落较东海海域具有较高的能量传递效率。浮游动物标准化生物量谱的截距在四个群落的大小顺序依次为：东海近岸群落>东海陆架群落>黄、东海交汇群落>黄海群落，表明较小粒径级浮游动物的生产力在东海近岸群落最高，在黄海群落最低。
在北太平洋低纬度西边界流海域上层（0—200m），分别于2012年冬季（11月至12月）和2014年秋季（10月至11月）对海域进行调查。共鉴定浮游动物类群13个，包括桡足类、磷虾类、毛颚类、水母类、被囊类、介形类、端足类、腹足类、莹虾类（Luciferida）、多毛类、仔稚鱼、无节幼体和其它浮游动物等。冬季，浮游动物丰度的变化范围为35.1—456.8 ind. m^-3，平均为206.6 ± 128.6 ind. m^-3，浮游动物体积生物量的变化范围为4.3—231.7 mm³ m^-3，平均为55.2 ± 55.5 mm³ m^-3。桡足类、被囊类和毛颚类在丰度和体积生物量方面均为三大优势类群。根据浮游动物标准化生物量谱的结果，浮游动物可划分为四个群落：北赤道流群落、赤道逆流群落、黑潮群落和棉兰老涡群落，其分布主要受到不同海流的影响。秋季，浮游动物丰度的变化范围为51.7—505.1 ind. m^-3，平均为181.9±113.5 ind. m^-3，其中，桡足类、介形类和毛颚类为三大优势类群。浮游动物体积生物量的变化范围为4.1—138.1 mm³ m^-3，平均为46.2±38.0 mm³ m^-3，其中，桡足类、毛颚类和磷虾类是三大优势类群。根据浮游动物标准化生物量谱的结果，浮游动物可划分为两个群落：大洋北部群落和大洋南部群落。浮游动物群落结构具有明显的季节变化。
北太平洋低纬度西边界流海域上层（0—200m）的浮游动物群落的标准化生物量谱的斜率均大于或接近于−1，说明北太平洋低纬度西边界流海域上层的浮游动物群落处于较稳定的状态，且具有能量传递效率高的特征。浮游动物群落的标准化生物量谱的斜率在冬季群落（北赤道流群落、赤道逆流群落、黑潮群落和棉兰老涡群落）较秋季群落（大洋北部群落和大洋南部群落）更为平缓，说明冬季的浮游动物群落具有更高的能量传递效率，但秋季的浮游动物群落更为稳定。根据浮游动物标准化生物量谱截距的大小顺序，冬季，较小粒径级浮游动物的生产力在赤道逆流群落最高，在北赤道流群落最低；秋季，较小粒径级浮游动物的生产力在大洋南部群落高于大洋北部群落。
在西太平洋浮游动物群落结构的垂直分布方面（0—3000m），根据2014年秋季（8月至10月）的调查结果，共鉴定浮游动物类群13个，包括桡足类、磷虾类、毛颚类、水母类、被囊类、介形类、端足类、腹足类、多毛类、仔稚鱼、无节幼体、有孔虫和其它浮游动物等。浮游动物类群组成随深度增加具有较大变化。浮游动物的丰度和体积生物量均随水深增加呈现降低的趋势，丰度随水深增加而降低的模式符合幂函数回归模型，而体积生物量随水深增加而降低的模式符合指数函数回归模型。浮游动物标准化生物量谱的斜率随水深增加呈现增加的趋势，说明随水深增加，大个体的浮游动物所占比例逐渐增大。根据浮游动物标准化生物量谱的结果，浮游动物在垂直方向上可划分为三个群落，其基本对应于光学分层，即海洋光合作用带、中层带和深层带。
在西太平洋海域垂直方向上，浮游动物群落的标准化生物量谱的斜率均大于−1，说明西太平洋的浮游动物群落在垂直分布上（0—3000m）处于一个能量传递效率高的状态。浮游动物标准化生物量谱的斜率在海洋光合作用带群落最为陡峭，在海洋深层带群落最为平缓，而截距在海洋光合作用带群落最高，在海洋深层带群落最低，说明海洋光合作用带的浮游动物群落具有较高的生产力，但其能量传递效率较低，而海洋深层带的浮游动物群落具有相对较低的生产力和较高的能量传递效率。

Zooplankton play a central role in marine ecosystem. Moreover, zooplankton can indicate global climate change and ocean circulation. As one of the marginal sea of the Western Pacific Ocean, China Sea was influenced by the pacific western boundary currents. Western Pacific develops a unique ecosystem owing to the extraordinary geographical environment and complex current system and is regarded as a center of origin with high species diversity. Thus, it is of great significance to carry on zooplankton research. In the present study, zooplankton community structure in the Yellow Sea, the East China Sea and the Pacific western boundary currents of the North Pacific was evaluated based on the ZooScan Integrated System and the normalized biomass size spectra. It aims to provide basic data for the study on large scale changes in zooplankton community structure from Chinese Coastal Regions to Western Pacific.
In the Yellow Sea, based on the samples collected during August of 2013, significant correlations were detected between zooplankton biovolume calculated by ZooScan Integrated System and dry mass, carbon content, nitrogen content calculated by traditional measurement. Moreover, zooplankton communities based on ZooScan Integrated System was consistent with the results of previous studies. Thus, ZooScan Integrated System was proved to provide an efficient and feasible method to study the zooplankton community structure in China Sea.
In the Yellow Sea and the East China Sea, samples were collected during autumn of 2014. Zooplankton were sorted into 17 diverse taxonomic groups: Copepoda, Euphausiacea, Chaetognatha, Medusa, Tunicata, Ostracoda, Amphipoda, Gastropoda, Polychaeta, Fish larvae, Nauplius, Noctiluca scintillans, Cladocera, Foraminifera, Radiolaria, Fish eggs, and other zooplankton. Zooplankton abundance ranged from 571.4 to 65995.1 ind. m^-3 (average 6988.0±11008.1 ind. m^-3), and the dominant groups were Copepoda, Noctiluca scintillans, and Tunicata. Zooplankton biovolume ranged from 62.7 to 13050.2 mm³ m^-3 (average 1468.3±2364.8 mm³ m^-3), and the dominant groups were Copepoda, Medusa, and Chaetognatha. According to the normalized biovolume size spectra, zooplankton communities were classified into four groups: the Yellow Sea group, the Yellow Sea and East China Sea Mixed group, the East China Sea Neritic group, and the East China Sea Shelf group, which were influenced by the water mass, sea temperature, and the latitude.
For the Yellow Sea and the East China Sea, the slopes of the normalized biovolume size spectra for each group were slightly flatter than −1, which indicates that zooplankton communities in the Yellow Sea and the East China Sea were characterized by high energy transfer efficiency. The slopes for the Yellow Sea group and the Yellow Sea and East China Sea Mixed group were −0.66, while those for the East China Sea Neritic group and the East China Sea Shelf group were −0.72, which indicated that zooplankton communities in the Yellow Sea was more efficiently in energy transfer than that in the East China Sea. The intercepts of the normalized biovolume size spectra were in order of the East China Sea Neritic group > the East China Sea Shelf group > the Yellow Sea and East China Sea Mixed group > the Yellow Sea group, which indicated that the production for small size zooplankton was highest in the East China Sea Neritic group and lowest in the Yellow Sea group.
In the western boundary currents of the North Pacific (0—200 m), samples were collected during winter of 2012 and autumn of 2014, respectively. Zooplankton were sorted into 13 diverse taxonomic groups: Copepoda, Euphausiacea, Chaetognatha, Medusa, Tunicata, Ostracoda, Amphipoda, Gastropoda, Luciferida, Polychaeta, Fish larvae, Nauplius, and other zooplankton. In winter, the dominant groups were Copepoda, Tunicata, and Chaetognatha. Zooplankton abundance and biovolume ranged from 35.1 to 456.8 ind. m^-3 (average 206.6 ± 128.6 ind. m^-3) and 4.3 to 231.7 mm³ m^-3 (average 55.2 ± 55.5 mm³ m^-3), respectively. According to the normalized biovolume size spectra, zooplankton communities were classified into four groups, which basically coincided with the geographical patterns of different currents: the North Equatorial Current, the North Equatorial Counter Current, the Kuroshio Current, and the Mindanao Eddy, respectively. In autumn, zooplankton abundance ranged from 51.7 to 505.1 ind. m^-3 (average 181.9±113.5 ind. m^-3), and the dominant groups were Copepoda, Ostracoda, and Chaetognatha. Zooplankton biovolume ranged from 4.1 to 138.1 mm³ m^-3 (average 46.2±38.0 mm³ m^-3), and the dominant groups were Copepoda, Chaetognatha, and Euphausiacea. According to the normalized biovolume size spectra, zooplankton communities were classified into two groups: the Pacific North group and the Pacific South group. Seasonal variation was detected for the zooplankton communities.
For the western boundary currents of the North Pacific (0—200 m), the slopes of the normalized biovolume size spectra for each group were slightly flatter than or close to −1, which indicates that zooplankton communities in the western boundary currents of the North Pacific were characterized by high energy transfer efficiency. The slopes for groups in winter were flatter than those for groups in autumn, which indicated that zooplankton communities in winter was more efficiently in energy transfer, while that in autumn was more stable. According to the order of the intercepts of the normalized biovolume size spectra, the highest production for small size zooplankton were observed in the North Equatorial Counter Current group (in winter) and the Pacific South group (in autumn), while the lowest production for small size zooplankton were detected in the North Equatorial Current group (in winter) and the Pacific North group (in autumn).
For the vertical distribution of zooplankton communities in the North Pacific, samples were collected down to 3000 m depths during autumn of 2014. Zooplankton were sorted into 13 diverse taxonomic groups: Copepoda, Euphausiacea, Chaetognatha, Medusa, Tunicata, Ostracoda, Amphipoda, Gastropoda, Polychaeta, Fish larvae, Nauplius, Foraminifera, and other zooplankton. The taxa composition of zooplankton varied greatly with increasing depths. Both the zooplankton abundance and biovolume decreased as the depth increased. The pattern of declining zooplankton abundance with depth was described better by a power regression model, whereas that of the biovolume fitted better to an exponential regression model. The slope of the normalized biovolume size spectra became flatter with increasing depths, which indicated that larger body size was observed with greater depth. According to the normalized biovolume size spectra, zooplankton communities were classified into three groups, which basically coincided with the vertical patterns of the optical layers of water, i.e., the epipelagic zone, the mesopelagic zone, and the bathypelagic zone, respectively.
For the North Pacific down to 3000 m depths, the slopes of the normalized biovolume size spectra for each group were lower than −1, which indicates that the zooplankton communities down to great depths (3000m) of North Pacific were characterized by high energy transfer efficiency. The slope for the epipelagic zone group was the most steep and that for the bathypelagic zone group was the most flat, while the intercept was highest in the epipelagic zone group and was lowest in the bathypelagic zone group, which indicated that zooplankton communities in the epipelagic zone was characterized by relatively high production and low energy transfer efficiency, while that in the bathypelagic zone was characterized by relatively low production and high energy transfer efficiency.