Journal of Tropical Oceanography ›› 2023, Vol. 42 ›› Issue (2): 87-96.doi: 10.11978/2022057CSTR: 32234.14.2022057

Previous Articles     Next Articles

Vertical distribution of zooplankton in the “Haima” cold seep region based on ZooScan image analysis

LI Ruofei1,2(), KE Zhixin1,2,3(), LI Kaizhi1,2,3, LIU Jiaxin1,2,3, TAN Yehui1,2,3   

  1. 1. Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
    3. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
  • Received:2022-03-24 Revised:2022-05-01 Online:2023-03-10 Published:2022-05-05
  • Contact: KE Zhixin. email: kzx@scsio.ac.cn
  • Supported by:
    Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)(GML2019ZD0401); National Natural Science Foundation of China(32171548); National Natural Science Foundation of China(31971432); National Natural Science Foundation of China(41976112); Science and Technology Basic Resources Investigation Program of China(2017FY201404)

Abstract:

To understand the vertical distributions of zooplankton in regions of the “Haima” cold seep and the possible effects of seep activities, zooplankton samples were collected from 0 to 1250 m at five stations in September 2020. These zooplankton samples were analyzed using ZooScan image analysis system. The abundance, biovolume and size spectra of zooplankton in different water layers were obtained in this study. The results showed that zooplankton abundance and biovolume were mainly occurred in the 0 ~ 100 m water layer. Below 100 m, zooplankton abundance and biovolume decreased rapidly with increased depth. The average abundance and biovolume of zooplankton were only 8.33 ind·m-3 and 12.10 mm3·m-3 at the layer of 1000 ~ 1250 m. In general, copepods were the dominant zooplankton in each water layer, and the proportion of gelatinous zooplankton increased in deep layer. The slope of normalized biovolume size spectra (NBSS) in the regions of the “Haima” cold seep ranged from -0.94 to -0.57, and the intercept ranged from -2.10 to 5.94. From surface to bottom, the slope of NBSS increased while the intercept decreased gradually. This indicated that the productivity of planktonic ecosystem declined gradually from surface to bottom, but the energy transfer efficiency of pelagic food web increased gradually. The layer of 1000 ~ 1250 m at ROV1 station showed abnormal size spectrum characteristics, and the slope “a” is significantly lower than that of other stations in the same water layer. It suggested that the zooplankton community might be affected by cold seep activities.

Key words: zooplankton, normalized biovolume size spectra, cold seep, image identification, deep sea