Eukaryotic influence on the oceanic biological carbon pump in the Scotia Sea as revealed by 18S rRNA gene sequencing of suspended and sinking particles
Eukaryotic influence on the oceanic biological carbon pump in the Scotia Sea as revealed by 18S rRNA gene sequencing of suspended and sinking particles
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DOI：
10.1002/lno.11319
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发表时间：
2019-09-09
影响因子：
4.5
通讯作者：
Lam, Phyllis
中科院分区：
文献类型：
--
作者：
Duret, Manon T.;Lampitt, Richard S.;Lam, Phyllis
悬浮的海洋颗粒构成了海洋中大部分颗粒有机物库，从而为异养生物提供了大量的基质，特别是在中层。相反，下沉颗粒是决定生物碳泵（BCP）强度的碳通量的主要贡献者。这项研究首次利用 18S rRNA 基因测序技术，对南大洋斯科舍海混合层和上中层海洋捕雪器收集的颗粒物进行了 18S rRNA 基因测序，研究了真核生物群落对悬浮和下沉颗粒物的不同影响。在中层上部，大多数真核浮游植物序列属于沉没颗粒中的链形成硅藻和悬浮颗粒中的原藻植物。这表明，富含硅藻的颗粒比斯科舍海富含硅藻的颗粒更能有效地将碳转移到中层上部，后者更容易分解成悬浮颗粒。在中层上部，桡足类似乎对下沉颗粒的影响最大，而软组织后生动物序列对悬浮颗粒的贡献更大。混合层和中层上部的异养原生生物和真菌群落是不同的，这意味着很少有原生生物沿着下沉的颗粒行驶。此外，悬浮颗粒和下沉颗粒之间的捕食性鞭毛虫和放射虫之间的差异意味着两个颗粒池之间不同的生态条件以及在 BCP 中的作用。与专注于下沉颗粒的经典碳输出研究相比，下沉和悬浮颗粒的分子分析构成了强大的诊断工具，可以更全面地研究真核生物对 BCP 的影响。
Suspended marine particles constitute most of the particulate organic matter pool in the oceans, thereby providing substantial substrates for heterotrophs, especially in the mesopelagic. Conversely, sinking particles are major contributors to carbon fluxes defining the strength of the biological carbon pump (BCP). This study is the first to investigate the differential influence of eukaryotic communities to suspended and sinking particles, using 18S rRNA gene sequencing on particles collected with a marine snow catcher in the mixed layer and upper mesopelagic of the Scotia Sea, Southern Ocean. In the upper mesopelagic, most eukaryotic phytoplankton sequences belonged to chain-forming diatoms in sinking particles and to prymnesiophytes in suspended particles. This suggests that diatom-enriched particles are more efficient in carbon transfer to the upper mesopelagic than those enriched in prymnesiophytes in the Scotia Sea, the latter more easily disintegrating into suspended particles. In the upper mesopelagic, copepods appeared most influential on sinking particles whereas soft-tissue metazoan sequences contributed more to suspended particles. Heterotrophic protists and fungi communities were distinct between mixed layer and upper mesopelagic, implying that few protists ride along sinking particles. Furthermore, differences between predatory flagellates and radiolarians between suspended and sinking particles implied different ecological conditions between the two particles pools, and roles in the BCP. Molecular analyses of sinking and suspended particles constitute powerful diagnostic tools to study the eukaryotic influence on the BCP in a more holistic manner compared to classic carbon export studies focusing on sinking particles.