Kersten Oliver, Vetter Eric W, Jungbluth Michelle J, Smith Craig R, Goetze Erica
Hawaii Pacific University, Kaneohe, HI, United States of America.
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway.
PeerJ. 2019 Sep 26;7:e7691. doi: 10.7717/peerj.7691. eCollection 2019.
Abyssal plains are among the most biodiverse yet least explored marine ecosystems on our planet, and they are increasingly threatened by human impacts, including future deep seafloor mining. Recovery of abyssal populations from the impacts of polymetallic nodule mining will be partially determined by the availability and dispersal of pelagic larvae leading to benthic recolonization of disturbed areas of the seafloor. Here we use a tree-of-life (TOL) metabarcoding approach to investigate the species richness, diversity, and spatial variability of the larval assemblage at mesoscales across the abyssal seafloor in two mining-claim areas in the eastern Clarion Clipperton Fracture Zone (CCZ; abyssal Pacific). Our approach revealed a previously unknown taxonomic richness within the meroplankton assemblage, detecting larvae from 12 phyla, 23 Classes, 46 Orders, and 65 Families, including a number of taxa not previously reported at abyssal depths or within the Pacific Ocean. A novel suite of parasitic copepods and worms were sampled, from families that are known to associate with other benthic invertebrates or demersal fishes as hosts. Larval assemblages were patchily distributed at the mesoscale, with little similarity in OTUs detected among deployments even within the same 30 × 30 km study area. Our results provide baseline observations on larval diversity prior to polymetallic nodule mining in this region, and emphasize our overwhelming lack of knowledge regarding larvae of the benthic boundary layer in abyssal plain ecosystems.
深海平原是地球上生物多样性最丰富但探索最少的海洋生态系统之一，它们正日益受到人类活动的威胁，包括未来的深海海底采矿。深海种群从多金属结核开采的影响中恢复，将部分取决于浮游幼虫的可用性和扩散，这会导致海底受干扰区域的底栖生物重新定殖。在这里，我们使用生命树（TOL）元条形码方法，来研究克拉里昂-克利珀顿断裂带东部（CCZ；太平洋深海）两个采矿申请区域内，深海海底中尺度上幼虫组合的物种丰富度、多样性和空间变异性。我们的方法揭示了小型浮游生物组合中一个前所未知的分类丰富度，检测到来自12个门、23个纲、46个目和65个科的幼虫，包括一些以前在深海深度或太平洋内未报告过的分类群。采集到了一组新的寄生桡足类动物和蠕虫，它们来自已知与其他底栖无脊椎动物或底栖鱼类宿主相关的科。幼虫组合在中尺度上呈斑块状分布，即使在同一个30×30公里的研究区域内，不同部署之间检测到的操作分类单元（OTU）也几乎没有相似性。我们的结果提供了该区域多金属结核开采之前幼虫多样性的基线观测数据，并强调了我们对深海平原生态系统中底栖边界层幼虫的极度缺乏了解。
