The potential of sedimentary ancient DNA for reconstructing past sea ice evolution
The potential of sedimentary ancient DNA for reconstructing past sea ice evolution
复制标题
DOI：
10.1038/s41396-019-0457-1
复制
发表时间：
2019-10-01
期刊：
影响因子：
11
通讯作者：
Larsen, Aud
中科院分区：
文献类型：
--
作者：
De Schepper, Stijn;Ray, Jessica L.;Larsen, Aud
海冰是北极气候系统的一个重要组成部分，但记录历史和地质时间尺度上海冰状况演变的工具很少，而且有局限性。这些记录对于记录和了解北极海冰范围的自然变化至关重要。在这里，我们探讨沉积古DNA（aDNA），作为一种新的工具，解锁和利用遗传（真核生物）生物多样性保存在海洋沉积物中，专门用于过去的海冰重建。虽然使用沉积aDNA在古海洋学和古气候研究仍处于起步阶段，我们在这里使用metabarcoding和单物种定量DNA检测方法记录海冰条件下的格陵兰海海洋沉积物芯。元条码可以识别地质记录中的生物多样性变化，这些变化几乎与10万年前的海冰变化有关。详细的生物信息学分析的metabarcoding数据揭示了几个海冰相关的类群，其中大部分以前未知的化石记录。最后，我们定量追踪了一个已知的海冰甲藻在沉积物芯。我们表明，aDNA可以从深海沉积物中回收，一般是含氧的底部沃茨，过去的海冰条件可以记录仪器的时间尺度之外。我们的研究结果证实了传统工具所做的海冰重建，从而证明了沉积aDNA的潜力，主要集中在微生物真核生物，作为一种新的工具，以更好地了解海冰在气候系统中的演变。
Sea ice is a crucial component of the Arctic climate system, yet the tools to document the evolution of sea ice conditions on historical and geological time scales are few and have limitations. Such records are essential for documenting and understanding the natural variations in Arctic sea ice extent. Here we explore sedimentary ancient DNA (aDNA), as a novel tool that unlocks and exploits the genetic (eukaryote) biodiversity preserved in marine sediments specifically for past sea ice reconstructions. Although use of sedimentary aDNA in paleoceanographic and paleoclimatic studies is still in its infancy, we use here metabarcoding and single-species quantitative DNA detection methods to document the sea ice conditions in a Greenland Sea marine sediment core. Metabarcoding has allowed identifying biodiversity changes in the geological record back to almost similar to 100,000 years ago that were related to changing sea ice conditions. Detailed bioinformatic analyses on the metabarcoding data revealed several sea-ice-associated taxa, most of which previously unknown from the fossil record. Finally, we quantitatively traced one known sea ice dinoflagellate in the sediment core. We show that aDNA can be recovered from deep-ocean sediments with generally oxic bottom waters and that past sea ice conditions can be documented beyond instrumental time scales. Our results corroborate sea ice reconstructions made by traditional tools, and thus demonstrate the potential of sedimentary aDNA, focusing primarily on microbial eukaryotes, as a new tool to better understand sea ice evolution in the climate system.