渤海浮游植物群落的长期变化(1959~2015).

Long-term changes on phytoplankton community in the Bohai Sea (1959~2015)

中文关键词: 浮游植物  群落结构  长期变化  渤海

英文关键词: Phytoplankton  Community structure  Long-Term changes  Bohai Sea

中文摘要:

      基于渤海1959~2015年间的网采浮游植物调查资料，研究了物种组成、丰度、群落结构及多样性的长期变化。50余年来，共记录浮游植物77属170种，生态类型主要为温带近岸性种；优势种组成出现明显的格局转换，20世纪以角毛藻(Chaetoceros)和圆筛藻(Coscinodiscus)等中心硅藻为主，进入21世纪后，具槽帕拉藻(Paralia sulcata)、海线藻(Thalassionema)以及甲藻中的夜光藻(Noctiluca scintillans)和角藻(Tripos)开始形成绝对优势；历次调查浮游植物丰度变化在(8.33~472) × 104 cells/m3之间，硅藻占到了65.3%~99.8%；丰度和多样性水平在20世纪逐渐降低，进入21世纪分别有1.5倍和15.0%的回升。渤海N/P比的长期持续升高，导致群落结构由硅藻主导演替到硅、甲藻共同控制，21世纪甲、硅藻比的平均水平较20世纪升高了2.82倍。浮游植物群落结构和饵料基础的年代际变动，影响到关键资源生物的早期补充过程，本研究为探讨渤海主要渔业种群对环境长期变化的适应性响应机制，提供基础资料和参考依据。

英文摘要:

      Based on phytoplankton net samples from the Bohai Sea from 1959 to 2015, the long-term changes in species composition, cell abundance, community structure, and species diversity were analyzed. A total of 77 genera and 170 taxa were recorded, most of which were temperate-coastal ecotype species. The composition pattern of the dominant taxa changed dramatically over the fifty-plus years. Centric diatoms such as Chaetoceros spp. and Coscinodiscus spp. dominated in the communities of last century, while Paralia sulcata, Thalassionema spp., and dinoflagellates such as Noctiluca scintillans and Tripos spp. gradually became predominant in this century. The cruise-averaged cell abundances ranged from 8.33 × 104 cells/m3 to 472 × 104 cells/m3, with diatoms accounting for 65.3%~99.8%. The abundances and species diversities declined to their lowest levels last century, whilst they had 1.5 times and 15.0% respective recoveries in this century. The persistent increase in seawater N∶P ratios in the Bohai Sea has led to a phytoplankton transition from diatom-dominated communities to communities co-dominated by diatoms and dinoflagellates, with an increase of 2.82 times in the ratio of diatoms to dinoflagellates in this century from that in the last century. The decadal changes in the phytoplankton community structure and its herbal diet basis in the Bohai Sea affect the recruitment process during the early life stages of the key resource species. This study provides a baseline database and references for discussion on the mechanisms of adaptive responses of fishery populations to the long-term environmental changes in the Bohai Sea.