Insights into global diatom distribution and diversity in the world's ocean
Insights into global diatom distribution and diversity in the world's ocean
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DOI：
10.1073/pnas.1509523113
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发表时间：
2016-03-15
影响因子：
11.1
通讯作者：
Bowler, Chris
中科院分区：
文献类型：
--
作者：
Malviya, Shruti;Scalco, Eleonora;Bowler, Chris
硅藻（硅藻门）是浮游植物中最具多样性和生态重要性的类群之一。它们被认为在营养丰富的沿海生态系统和高纬度地区特别重要，但在贫营养的开阔海洋中就不那么重要了。塔拉海洋环球航行使用标准化的采样程序从广泛的海洋区域收集样本。在这里，共有类似的1200万硅藻V9- 18 S核糖体DNA（rDNA）核糖体型，来自293个大小分级浮游生物群落收集在46个采样点在全球海洋真光区，进行了分析，探索硅藻的全球多样性和社区组成。我们在4，748个操作分类单位（OTU）提供了海洋浮游硅藻多样性的新估计。根据总的核糖体类型，角毛藻是最丰富和多样的属，其次是脆杆藻，海链藻和Corethron。我们发现只有少数世界性的核糖体类型显示出均匀分布在各站和高丰度，其中许多不能被分配与任何已知的属的信心。从南太平洋，地中海，南大洋沃茨三个不同的社区被确定为共享一个相当大的比例的核糖型内。在分隔印度洋和大西洋的厄古哈斯角，以及大西洋和南大洋之间的德雷克海峡，观察到多样性突然下降，表明这些海洋环流瓶颈在限制硅藻分布和多样性方面的重要性。我们还观察到开放海洋中硅藻的高多样性，这表明硅藻在这些海洋系统中可能比通常认为的更相关。
Diatoms (Bacillariophyta) constitute one of the most diverse and ecologically important groups of phytoplankton. They are considered to be particularly important in nutrient-rich coastal ecosystems and at high latitudes, but considerably less so in the oligotrophic open ocean. The Tara Oceans circumnavigation collected samples from a wide range of oceanic regions using a standardized sampling procedure. Here, a total of similar to 12 million diatom V9-18S ribosomal DNA (rDNA) ribotypes, derived from 293 size-fractionated plankton communities collected at 46 sampling sites across the global ocean euphotic zone, have been analyzed to explore diatom global diversity and community composition. We provide a new estimate of diversity of marine planktonic diatoms at 4,748 operational taxonomic units (OTUs). Based on the total assigned ribotypes, Chaetoceros was the most abundant and diverse genus, followed by Fragilariopsis, Thalassiosira, and Corethron. We found only a few cosmopolitan ribotypes displaying an even distribution across stations and high abundance, many of which could not be assigned with confidence to any known genus. Three distinct communities from South Pacific, Mediterranean, and Southern Ocean waters were identified that share a substantial percentage of ribotypes within them. Sudden drops in diversity were observed at Cape Agulhas, which separates the Indian and Atlantic Oceans, and across the Drake Passage between the Atlantic and Southern Oceans, indicating the importance of these ocean circulation choke points in constraining diatom distribution and diversity. We also observed high diatom diversity in the open ocean, suggesting that diatoms may be more relevant in these oceanic systems than generally considered.