School of Oceanography, Yantai University, Yantai, 264005, China.
Shandong Marine Resource and Environment Research Institute, Yantai, 264006, China.
Mar Environ Res. 2024 Nov;202:106734. doi: 10.1016/j.marenvres.2024.106734. Epub 2024 Sep 7.
Laizhou Bay, a major breeding ground for economic marine organisms in the northern waters of China, is facing rapid environmental degradation. In this study, field surveys in this area were conducted in the spring, summer, and autumn of 2020. Microscopic observation and RuBisCO large subunit (rbcL) gene analysis were employed to understand the community structure and temporal dynamics of phytoplankton. The phytoplankton community structures detected by the two methods showed significant differences. Microscopic observation revealed the dominance of dinoflagellates in spring that shifted to the dominance of diatoms in summer and autumn. However, rbcL gene sequencing consistently identified diatoms as dominant throughout all three seasons, with their relative abundance showing an increasing trend. Conversely, the relative abundance of the second- and third-most abundant taxa, namely, haptophytes and ochrophytes, decreased as the seasons transitioned. rbcL gene sequencing annotated more species than microscopy. It could detect haptophytes and cryptophytes, which were overlooked by microscopy. In addition, rbcL gene sequencing detected a remarkable amount of Thalassiosira profunda, which was previously unidentified in this sea area. However, it appeared to underestimate the contribution of dinoflagellates considerably, with most taxa being only identified through microscopic identification. The two methods jointly identified 28 harmful algal bloom taxa with similar detection quantities but substantial differences in species composition. Phytoplankton communities were influenced by temperature, salinity, and nutrients. The results of this work suggest that a combination of multiple techniques is necessary for a comprehensive understanding of phytoplankton.
莱州湾是中国北方海域重要的经济海洋生物养殖区，但正面临着快速的环境退化。本研究于 2020 年春、夏、秋三季对该海域进行了实地调查。采用显微镜观察和 RuBisCO 大亚基（rbcL）基因分析的方法，研究了浮游植物的群落结构和时间动态。这两种方法检测到的浮游植物群落结构存在显著差异。显微镜观察显示，春季以甲藻为主，夏季和秋季则以硅藻为主。然而，rbcL 基因测序始终表明硅藻在所有三个季节都占优势，其相对丰度呈上升趋势。相反，第二和第三丰富度的类群，即甲藻和黄藻，随着季节的变化而减少。rbcL 基因测序注释的物种比显微镜观察多。它可以检测到甲藻和隐藻，而这些在显微镜观察中被忽略了。此外，rbcL 基因测序检测到大量的深大洋链藻，这在该海域以前是未被识别的。然而，它似乎大大低估了甲藻的贡献，大多数类群仅通过显微镜鉴定识别。这两种方法共同鉴定出 28 种有害赤潮藻，它们的检测数量相似，但物种组成有很大差异。浮游植物群落受到温度、盐度和营养物质的影响。这项工作的结果表明，需要结合多种技术才能全面了解浮游植物。
