Journal of Marine Sciences ›› 2019, Vol. 37 ›› Issue (3): 86-96.DOI: 10.3969/j.issn.1001-909X.2019.03.011

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Net-collected phytoplankton community structure in relation to environmental factors in the continental shelf of the northern South China Sea in spring 2015

SU Li1,2, CHEN Zuo-zhi*1,2,3, HUANG Zi-rong1,2, XU You-wei1,2   

  1. 1. South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China;
    2. Key Laboratory of Open-Sea Fishery Development, Ministry of Agriculture and Rural Affairs,Guangzhou 510300, China;
    3. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
  • Received:2019-01-07 Revised:2019-08-18 Online:2019-09-15 Published:2022-11-14

Abstract: The northern South China Sea, located in tropical and subtropical areas,is one of the important fishing grounds along the coast of China and has abundant fishery resources. Phytoplankton are the basic link in the marine food chain, change in their community structure will directly or indirectly influence fishery resources. According to the survey data in May 2015, the structure characteristics of phytoplankton community and its relationship with environmental factors were analyzed. The results showed that a total of 378 species (excluding the unidentified species) belonging to 4 phyla were identified, including 209 species of diatoms, 157 species of dinoflagellate, 9 species of cyanobacteria and 3 species of chromophyte. The dominant species were Proboscia alata,Proboscia alata f. gracillima,Thalassiothrix frauenfeldii,Pseudo-nitzschia pungens,Eucompia zoodiacus and Chaetoceros lorenzianus.The dominant species differed obviously among sections, only Thalassiothrixfrauenfeldii was dominant along four sections. The phytoplankton abundance ranged from 0.63×104 cells/m3 to 1 430.04×104 cells/m3, with an average of 76.20×104 cells/m3. Diatoms were overwhelmingly dominant in phytoplankton community, which abundance ranged from 0.3×104 cells/m3 to 1 420.39×104 cells/m3, with an average of 72.89×104 cells/m3, accounting for 95.66%. Dinoflagellate abundance ranged from 0.03×104 cells/m3 to 23.78×104 cells/m3, with an average of 2.71×104 cells/m3, accounting for 3.56%. Shantou section (H) had the highest abundance, with an average of 250.01×104 cells/m3, followed by Zhanjiang section (D), with an average of 99.48×104 cells/m3. The low abundances were found in the Pearl River Estuary (F), Shanwei (G) and Yangjiang (E) sections, with an average of 11.67×104 cells/m3, 10.61×104 cells/m3 and 9.23×104 cells/m3, respectively. High-abundance areas were mainly occurred at inshore stations in the Shantou (H) and Zhanjiang (D) sections. Overall, the phytoplankton Shannon-Wiener diversity index was high, ranged from 1.06 to 5.56,with an average of 3.99, indicating that the community structure of phytoplankton was relatively stable in the northern South China Sea in spring. Redundancy analysis showed that temperature, salinity and phosphate were the main environmental factors associated with the phytoplankton community structure in the northern South China Sea. Spearman's rank correlation analysis showed that abundances of phytoplankton, diatoms and dinoflagellates were negatively correlated with temperature. The results showed that the species composition, abundance distribution and dominant species composition of phytoplankton were different from section to section. Phytoplankton distribution was characterized by high nearshore and low offshore,and water temperature and salinity were the main environmental factors affecting its distribution in the continental shelf of the northern South China Sea in spring.

Key words: phytoplankton, environmental factors, northern South China Sea

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