人类活动和沿岸流影响下的粤东近海浮游动物群落特征

Zooplankton community in the coastal waters of eastern Guangdong under the influence of human activities and ocean currents

粤东附近海域具有丰富的渔业资源和复杂的水文环境。在气候变化背景下,为系统提升该海域海洋观测水平和生态动力过程的认知,于2022年5月(春季)、7月(夏季)、10月(秋季)和2023年1月(冬季)开展了四个季节的水文动力、生物、化学等生态环境要素的综合考察。基于镜检浮游动物的鉴定结果,分析该海域浮游动物群落特征,探讨其时空分布的影响因素。根据环境因子聚类,调查海域可分为近岸(主要受人类活动影响)和远岸(主要为海流影响)区域,不同季节和区域浮游动物群落结构存在显著差异。春、夏季浮游动物动物种类、生物量和丰度均高于秋、冬季;远岸区浮游动物种数、生物量和丰度显著高于近岸,并且浮游动物群落结构的季节差异在远岸区更加明显。桡足类和毛颚类为调查海域的主要浮游动物类群。浮游幼虫和鱼卵的丰度在春季显著高于其他季节,并且峰值集中在南澳岛西南韩江口附近海域,说明该区域为粤东重要的产卵场。受粤东沿岸上升流影响,夏季桡足类的种类和丰度增加;而冬季,浮游动物主要由闽浙沿岸流所携带的暖温带种所组成,中华哲水蚤(Calanus sinicus)在S8站位高达1000 ind.·m^(-3)。另外,近岸养殖区内的浮游动物出现种类少、生物量和丰度较低,个别调查站网采样品基本无浮游动物检出。在人类活动和气候变化的双重影响下,粤东近海浮游动物需要进行长期系统监测分析其对海洋环境变化的响应。

There are rich fishery resources and complicated hydrologic environment in the coastal waters of eastern Guangdong.In order to systematically improve the level of oceanic observation and the knowledge of ecological dynamic processes in the coastal waters of eastern Guangdong under the changing climate,a comprehensive investigation of ecological and environmental factors such as hydrodynamics,biology and chemistry during four seasons was carried out in May(spring),July(summer),October(autumn)2022 and January 2023(winter).Based on the taxonomic identification of zooplankton,the characteristics of community structure of zooplankton in the surveyed area were analyzed,and the effects of environmental factors on their spatial and temporal distribution were discussed.According to the environmental parameters,the survey area can be divided into the near-shore(mainly affected by human activities)and off-shore(mainly affected by ocean currents)areas,and the zooplankton were characterized by the seasonal and regional pattern.Seasonally,the species,biomass and abundance of zooplankton in spring and summer were higher than those in autumn and winter.Regionally,the species,biomass and abundance of zooplankton in the off-shore waters are generally higher than those in the near-shore waters.Moreover,there are differences in the contribution groups and dominant species to the total zooplankton abundance in different seasons in the off-shore waters.Although copepods and chaetognaths were the main groups of zooplankton,the abundance of planktonic larvae and fish eggs in spring was higher than in other seasons,and the peak value is concentrated in the southwestern Hanjiang Estuary,indicating that this surveyed area was still an important spawning ground in the coastal waters of eastern Guangdong.The increase in copepods species and abundance in summer is related to the high chlorophyll a concentration improved by coastal upwelling in eastern Guangdong.Warm-temperate species carried by Fujian and Zhejiang coastal currents in winter are the main contributors to zooplankton abundance.Although chlorophyll a concentrations are higher in the near-shore waters,zooplankton species,biomass and abundance are lower.Under the effect of anthropogenic activities and climate change,long-term systematic monitoring and analysis of the response of zooplankton to the dynamics of the marine environment are needed in the coastal waters of eastern Guangdong.