Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.
Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
Curr Biol. 2017 Jan 9;27(1):R15-R16. doi: 10.1016/j.cub.2016.11.032.
Ocean surface warming is resulting in an expansion of stratified, low-nutrient environments, a process referred to as ocean desertification [1]. A challenge for assessing the impact of these changes is the lack of robust baseline information on the biological communities that carry out marine photosynthesis. Phytoplankton perform half of global biological CO uptake, fuel marine food chains, and include diverse eukaryotic algae that have photosynthetic organelles (plastids) acquired through multiple evolutionary events [1-3]. While amassing data from ocean ecosystems for the Baselines Initiative (6,177 near full-length 16S rRNA gene sequences and 9.4 million high-quality 16S V1-V2 amplicons) we identified two deep-branching plastid lineages based on 16S rRNA gene data. The two lineages have global distributions, but do not correspond to known phytoplankton. How the newly discovered phytoplankton lineages contribute to food chains and vertical carbon export to the deep sea remains unknown, but their prevalence in expanding, low nutrient surface waters suggests they will have a role in future oceans.
海洋表面升温导致分层、低营养环境的扩张，这一过程被称为海洋荒漠化[1]。评估这些变化影响的一个挑战是缺乏关于进行海洋光合作用的生物群落的稳健基线信息。浮游植物完成了全球一半的生物 CO2 吸收，为海洋食物链提供燃料，其中包括通过多次进化事件获得光合作用细胞器（质体）的多种真核藻类[1-3]。在为基础倡议（6177 条近全长 16S rRNA 基因序列和 940 万条高质量 16S V1-V2 扩增子）从海洋生态系统中积累数据时，我们根据 16S rRNA 基因数据确定了两个深分支的质体谱系。这两个谱系具有全球分布，但与已知的浮游植物不对应。新发现的浮游植物谱系如何为食物链和垂直碳向深海输出做出贡献仍然未知，但它们在不断扩张、低营养的表层水中的普遍存在表明它们将在未来的海洋中发挥作用。
