Low diversity of a key phytoplankton group along the West Antarctic Peninsula
Low diversity of a key phytoplankton group along the West Antarctic Peninsula
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DOI：
10.1002/lno.11765
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发表时间：
2021-05-06
影响因子：
4.5
通讯作者：
Schofield, Oscar M.
中科院分区：
文献类型：
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作者：
Brown, Michael S.;Bowman, Jeff S.;Schofield, Oscar M.
西南极半岛(下称“半岛”)正在经历快速变暖和融化，影响着区域海洋食物网。半岛上的主要浮游植物群是硅藻和隐藻。相对于硅藻，很少有人关注地区性隐芽植物，因此我们对它们的多样性和生态学的了解有限，特别是在物种水平上。这一差距很重要，因为硅藻和隐芽植物在区域海洋食物网和生物地球化学中发挥着不同的作用。在这里，我们使用18S rRNA基因扩增序列变异的系统发育定位方法，在高分类分辨率下评估半岛沿岸表层海洋隐芽生物的多样性及其驱动因素。数据是在帕尔默长期生态研究计划的区域研究巡航期间(2012-2016)收集的。我们的结果表明，沿半岛有两个主要的隐芽植物分类群，由不同的Gminigera spp.组成，总体上几乎占到隐芽植物群落的100%(表明分类群均匀度较低)。初级分类群在所有样本/年份的隐芽植物群落中占据主导地位，这些样本/年跨越了广泛的海洋条件。隐藻群落组成在较低(较高)的初级(次生)类群百分比之间的变化与不同的海洋条件有关，包括较低(较高)的温度、盐度、营养物质和隐藻的相对丰度(浮游植物生物量和硅藻相对丰度)。这些结果强调有必要对这两个分类群的生态进行全面描述，因为据预测，鉴于区域环境持续变化的预测，半岛沿线的隐芽植物将会增加。
The West Antarctic Peninsula (henceforth "Peninsula") is experiencing rapid warming and melting that is impacting the regional marine food web. The primary phytoplankton groups along the Peninsula are diatoms and cryptophytes. Relative to diatoms, there has been little focus on regional cryptophytes, and thus our understanding of their diversity and ecology is limited, especially at the species level. This gap is important, as diatoms and cryptophytes play distinct roles in the regional marine food web and biogeochemistry. Here, we use a phylogenetic placement approach with 18S rRNA gene amplicon sequence variants to assess surface ocean cryptophyte diversity and its drivers at a high taxonomic resolution along the Peninsula. Data were collected over 5 years (2012-2016) during the regional research cruises of the Palmer Long-Term Ecological Research program. Our results indicate that there are two major cryptophyte taxa along the Peninsula, consisting of distinct Geminigera spp., which in aggregate always comprise nearly 100% of the cryptophyte community (indicating low taxa evenness). The primary taxon dominates the cryptophyte community across all samples/years, which span a broad range of oceanographic conditions. A shift in cryptophyte community composition between a lower (higher) primary (secondary) taxon percentage is associated with distinct oceanographic conditions, including lower (higher) temperature, salinity, nutrients, and cryptophyte relative abundance (phytoplankton biomass and diatom relative abundance). These results emphasize the need for a full characterization of the ecology of these two taxa, as it is predicted that cryptophytes will increase along the Peninsula given projections of continued regional environmental change.