The influence of Larsen-C ice-cover on macrobenthic peracarid crustacean assemblages on the Antarctic shelf

2017年7月12日，拉森-C冰架崩解了有记录以来起源于南极半岛的最大冰山(A68)，留下了新暴露在开阔海洋条件下的5800平方公里海床，这些海床很可能几个世纪以来甚至自上一次间冰期以来一直保持冰盖状态。这使我们能够处理与气候变化下极地大陆架的可持续性、底栖生物种群迁徙过程以及海洋底栖生物分布可以在多大程度上用来解释过去对气候变化的反应等基本问题。生物多样性的研究是在拉森-A和B冰架分别撤退5年和12年后才开始的。拉森-C珍珠项目现在将在2018年2月/3月RSS詹姆斯·克拉克·罗斯董事会开始大规模殖民之前调查新暴露的大陆架。2019年，该区域还将从RV Polarstein的董事会上进行采样，这将是极地研究中的第一次，它将能够在最早的机会生成关于生物多样性、底栖群落组成、物种周转和殖民、营养结构的基线描述，位于前冰盖区域之下。这项研究将是预测底栖系统对未来对冰架进一步崩溃的影响的反应的关键，并改善对极地大陆架生态系统弹性的基本理解，以支持有效的生态系统管理规则。该项目的主导假设是：“在拉森-C冰山A68崩解之前，冰架下海底的底栖动物很可能包含类似深海韦德尔海组合的寡营养组合。A68的崩解，以及海床暴露在开阔的海洋和海冰条件下，将引发新物种的迅速殖民，这些新物种将在短时间内显著改变海底生态系统。拉森-C珍珠将专注于珊瑚礁附近的甲壳类动物，并遵循以下四个主要目标：1.表层和海底表层和表层干旱甲壳类动物的生物多样性和组合结构评估；2.在拉森-C地区发现的选定的干旱地带物种的分类描述及其系统地理重建；3.拉森-C一年生物多样性和珊瑚礁组合结构的比较(2019年PS 118考察)与第0年和其他区域(例如菲尔奇纳海槽和无冰的南奥克尼群岛以及威德尔海的深海)的比较，以研究翻转、殖民和/或演替；4.确定拉森-C冰架下第0年和第二年冰架下以及无冰区之间的珊瑚礁功能群。

On 12 July 2017, the Larsen-C Ice Shelf calved the largest iceberg (A68) originating from the Antarctic Peninsula ever recorded leaving 5,800 km² of seabed newly exposed to open-marine conditions which had very likely remained ice-covered for centuries or even since the last inter-glacial period. This enables us to address fundamental questions relating to the sustainability of polar continental shelves under climate change, the processes by which benthic populations migrate, and the degree to which the distribution of marine benthos can be used to interpret past responses to climate change. Biodiversity was not studied until 5 and 12 years respectively after the retreats of Larsen-A & B ice shelves. The Larsen-C Pearl project will now investigate the newly exposed shelf before significant colonisation begins from board of the RSS James Clarke Ross in February/March 2018. In 2019 this area will also be sampled from board of the RV Polarstern and it will be able for the first time in polar research to generate a baseline description of biodiversity, benthic community composition, species' turnover and colonisation, trophic structure at the very earliest opportunity underneath a former ice-covered area. This research will be key to producing predictions of the benthic systems’ response to future impacts on further ice-shelf collapse and improve fundamental understanding about the resilience of polar continental shelf ecosystems for a support of effective ecosystem management regulations.The project’s governing hypothesis is: "Until the calving of the Larsen-C iceberg, A68, the benthic fauna on the seabed beneath ice shelf has likely comprised oligotrophic assemblages resembling deep-sea Weddell Sea assemblages. The calving of A68, and the exposure of the seabed to open-marine and sea-ice conditions will initiate a rapid colonisation by new species that will transform the benthic ecosystem significantly within a short timeframe."Larsen-C Pearl will focus on peracarid crustaceans and follow four major objectives: 1. Biodiversity and assemblage structure assessment of the epi- and suprabenthic peracarid crustaceans; 2. Taxonomic descriptions of the selected peracarid species discovered in the Larsen-C area and reconstruction of their phylogeography; 3. Comparison of Larsen-C Year-1 biodiversity and peracarid assemblage structure (PS 118 expedition in 2019) with Year-0 and other areas (e.g. Filchner Trough and the ice free South Orkney Islands as well as deep sea of the Weddell Sea) to investigate turn-over, colonisation and/or succession; 4. Identification of peracarid functional groups beneath the Larsen-C ice shelf in year-0 and the next year after the calving and between ice-free areas.