基于环境DNA宏条形码测序的楚科奇海和白令海鱼类多样性及丰度研究

Ecological environment in arctic region changes dramatically due to global warming and sea-ice decline, these changes could be reflected by marine fish diversity pattern. Characterized by unique geography, environmental features and fish fauna traits, Chukchi Sea and Bering Sea provide a favorable model for studies regarding the arctic and subarctic marine fish diversity pattern impacted by global climate change. However, the existing methods of fish diversity investigation have various disadvantages, thus, it is necessary to establish a new alternative approach. Our study aims to conduct eDNA metabarcoding, along with traditional survey method and historical survey data, to investigate fish diversity and abundance in Chukchi Sea and Bering Sea. We will establish an alternative fish diversity survey approach suitable for arctic and subarctic seas, investigate species composition and diversity pattern of fishes, and infer fish abundance from aqueous eDNA, thereby we can elucidate numbers and spatial distribution patterns of fishes, and reveal the ways that species composition and abundance distribution of fishes response to the changes of ecological environment in arctic and subarctic regions. Our work would draw a baseline for biodiversity conservation and management of ecosystem and fishery resource for arctic region, and provide fundamental data for studies regarding the mechanism of respond and feedback of arctic ecosystem to global climate change.

北极生态环境由于受到温度上升和海冰消退的影响而发生着显著变化，这些变化可以通过鱼类多样性格局的变迁而反映出来。楚科奇海和白令海独特的地理位置、环境特点和鱼类区系特征，为研究全球气候变化对北极和亚北极地区海洋鱼类多样性格局的影响提供了良好的系统模型。但现有的鱼类多样性调查方法均存在种种不足。本项目拟运用eDNA宏条形码测序，并结合传统调查方法和历史调查数据，对楚科奇海和白令海的鱼类多样性及丰度开展研究。构建一套适用于北极和亚北极海区的鱼类多样性新型调查方法体系；调查鱼类的种类组成及其多样性现状；推断eDNA中所包含的鱼类丰度信息；据此查明鱼类的数量和空间分布格局，探讨全球气候变化背景下其种类组成和数量分布对生态环境变化的响应方式。相关研究结果对于北极生物多样性的保护及生态系统和渔业资源的管理具有重要指导意义和参考价值，并能为研究北极生态系统对气候变化的响应和反馈机制提供部分基础信息。

本项目开展了基于eDNA宏条形码测序的北极海洋鱼类多样性新型调查方法体系构建与应用效果评估，通过梳理北极鱼类历史调查数据，筛选和评价了主要的鱼类eDNA宏条形码引物，并遴选出MiFish-U和L14841/15149R分别作为针对线粒体12S rRNA基因和Cyt b基因的最优eDNA宏条形码引物。.利用基于线粒体COI片段的北极鱼类DNA条形码分析，精准鉴定了北极鱼类种类，以此为基础开展了北极鱼类eDNA参考数据库的构建。在此过程中，还对北极鱼类中的广泛分布的绵鳚科重要种类——北极狼绵鳚（Lycodes polaris）开展了线粒体基因组全序列的测定。.依托中国北极科学考察航次，采集了北极海区鱼类生物样品以及海水和底表沉积物eDNA样品，并成功摸索出一套eDNA样品采集、保存和运输的方法流程。据此成功构建了一套基于eDNA宏条形码测序并且适用于北极地区的海洋鱼类多样性新型调查方法体系。在该方法体系下，揭示出北极海洋生态系统中的生态关键种——白令海北鳕（Boreogadus saida）在北冰洋中心海区调查区域的中上层水体空间分布格局特征。但由于调查站位较少且较为集中，同时调查海域缺乏历史调查数据，相关结果还需要更多证据加以佐证。