Chen Weidong, Pan Yongbo, Yu Lingyu, Yang Jun, Zhang Wenjing
State Key Laboratory of Marine Environmental Science, Marine Biodiversity and Global Change Research Center, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
Aquatic EcoHealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
Front Microbiol. 2017 Oct 12;8:1912. doi: 10.3389/fmicb.2017.01912. eCollection 2017.
Microeukaryotes play key roles in the structure and functioning of marine ecosystems. Little is known about the relative importance of the processes that drive planktonic and benthic microeukaryotic biogeography in subtropical offshore areas. This study compares the microeukaryotic community compositions (MCCs) from offshore waters ( = 12) and intertidal sediments ( = 12) around Xiamen Island, southern China, using high-throughput sequencing of 18S rDNA. This work further quantifies the relative contributions of spatial and environmental variables on the distribution of marine MCCs (including total, dominant, rare and conditionally rare taxa). Our results showed that planktonic and benthic MCCs were significantly different, and the benthic richness (6627 OTUs) was much higher than that for plankton (4044 OTUs) with the same sequencing effort. Further, we found that benthic MCCs exhibited a significant distance-decay relationship, whereas the planktonic communities did not. After removing two unique sites (N2 and N3), however, 72% variation in planktonic community was explained well by stochastic processes. More importantly, both the environmental and spatial factors played significant roles in influencing the biogeography of total and dominant planktonic and benthic microeukaryotic communities, although their relative effects on these community variations were different. However, a high proportion of unexplained variation in the rare taxa (78.1-97.4%) and conditionally rare taxa (49.0-81.0%) indicated that more complex mechanisms may influence the assembly of the rare subcommunity. These results demonstrate that patterns and processes in marine microeukaryotic community assembly differ among the different habitats (coastal water vs. intertidal sediment) and different communities (total, dominant, rare and conditionally rare microeukaryotes), and provide novel insight on the microeukaryotic biogeography and ecological mechanisms in coastal waters and intertidal sediments at local scale.
微型真核生物在海洋生态系统的结构和功能中发挥着关键作用。对于驱动亚热带近海区域浮游和底栖微型真核生物生物地理学的过程的相对重要性，我们知之甚少。本研究利用18S rDNA的高通量测序技术，比较了中国南方厦门岛周围近海水域（n = 12）和潮间带沉积物（n = 12）中的微型真核生物群落组成（MCCs）。这项工作进一步量化了空间和环境变量对海洋MCCs（包括总分类群、优势分类群、稀有分类群和条件稀有分类群）分布的相对贡献。我们的结果表明，浮游和底栖MCCs存在显著差异，在相同测序深度下，底栖生物的丰富度（6627个操作分类单元）远高于浮游生物（4044个操作分类单元）。此外，我们发现底栖MCCs呈现出显著的距离衰减关系，而浮游群落则没有。然而，去除两个独特站点（N2和N3）后，随机过程很好地解释了浮游群落72%的变异。更重要的是，环境和空间因素在影响浮游和底栖微型真核生物总群落和优势群落的生物地理学方面都发挥了重要作用，尽管它们对这些群落变异的相对影响有所不同。然而，稀有分类群（78.1 - 97.4%）和条件稀有分类群（49.0 - 81.0%）中高比例的无法解释变异表明，更复杂的机制可能影响稀有亚群落的组装。这些结果表明，海洋微型真核生物群落组装的模式和过程在不同栖息地（沿海水域与潮间带沉积物）和不同群落（总微型真核生物、优势微型真核生物、稀有微型真核生物和条件稀有微型真核生物）之间存在差异，并为局部尺度上海岸水域和潮间带沉积物中的微型真核生物生物地理学和生态机制提供了新的见解。
