Biodiv Sci ›› 2017, Vol. 25 ›› Issue (9): 981-989.DOI: 10.17520/biods.2017052

• Original Papers: Plant Diversity • Previous Articles     Next Articles

Spatio-temporal variation of benthic diatom diversity and community structure in a sandy intertidal zone of the Nanji Islands, China

Yuhang Li1, Wandong Chen2, Houcai Cai2, Zhongmin Sun1,4, Kuidong Xu1,3,4,*()   

  1. 1 Department of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong 266071
    2 Nanji Islands National Marine Natural Reserve Administration Bureau, Pingyang, Zhejiang 325401
    3 Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266071
    4 University of Chinese Academy of Sciences, Beijing 100049
  • Received:2017-02-21 Accepted:2017-07-26 Online:2017-09-20 Published:2017-10-04
  • Contact: Xu Kuidong
  • About author:# Co-first authors

Abstract:

To know the status and 20 years’ variation of benthic diatom biodiversity and community structure in intertidal sandy sediment in the Nanji Islands National Marine Nature Reserve (NINMNR) of China, we investigated community composition and seasonal variations of marine benthic diatoms between November 2013 and August 2014 in the intertidal zone of the Huokun’ao sandy beach in the NINMNR, and compared this to historic data obtained from intertidal sandy sediments of the Nanji Islands. A total of 120 benthic diatom species belonging to 49 genera were identified. Among these, 17 species were classified as dominant species, including Fallacia litoricola, Diploneis smithii and D. parca. The Shannon diversity index (H?) values of benthic diatoms varied between 2.388 and 3.455. The peak of H? appeared in spring, and the lowest value occurred in fall. Spatially, the highest H? value was present in the middle tidal zone and the lowest was found in the high tide zone. The result of analysis of similarities (ANOSIM) showed there were significant differences in the benthic community between the high, middle and low tidal areas, while no significant differences were observed between the four seasons. The result of BIOENV suggested that salinity was the most important factor regulating the benthic diatom community. The present study and historic data indicate that the community structure of benthic diatoms in the sandy sediments of Nanji Islands changed markedly over the past few decades. Compared with data obtained from three surveys conducted between 1981 and 1993, the number of diatom orders has decreased from 16 to 14, while the number of families has increased from 24 to 31, and the number of genera and species has significantly increased from 29 to 49 and from 55 to 120, respectively. The increase of diatom taxa is likely due to the enhanced intensity of taxonomic study. Nonetheless, the average taxonomic distinctness index (Δ+) values decreased from 79.79 to71.41. Strikingly, large attached diatoms recorded in the past have been replaced by small attached forms as well as epipelons. This could be the result of intense human activities and the long-term effects of over-discharged organic matter.

Key words: marine benthic diatoms, biodiversity, community structure, dominant species, Nanji Islands