Climate change is influencing some environmental variables in the Southern Ocean (SO) and this will have an effect on the marine biodiversity. Peracarid crustaceans are one of the dominant and most species-rich groups of the SO benthos. To date, our knowledge on the influence of environmental variables in shaping abundance and species composition in the SO’s peracarid assemblages is limited, and with regard to ice coverage it is unknown. The aim of our study was to assess the influence of sea ice coverage, chlorophyll-a, and phytoplankton concentrations on abundance, distribution and assemblage structure of peracarids. In addition, the influence of other physical parameters on peracarid abundance was assessed, including depth, temperature, salinity, sediment type, current velocity, oxygen, iron, nitrate, silicate and phosphate. Peracarids were sampled with an epibenthic sledge (EBS) in different areas of the Atlantic sector of the SO and in the Weddell Sea. Sampling areas were characterized by different regimes of ice coverage (the ice free South Orkney Islands, the seasonally ice-covered Filchner Trough and the Eastern Antarctic Peninsula including the Prince Gustav Channel which was formerly covered by a perennial ice shelf). In total 64766 individuals of peracarids were collected and identified to order level including five orders: Amphipoda, Cumacea, Isopoda, Mysidacea, and Tanaidacea. Amphipoda was the most abundant taxon, representing 32% of the overall abundances, followed by Cumacea (31%), Isopoda (29%), Mysidacea (4%), and Tanaidacea (4%). The Filchner Trough had the highest abundance of peracarids, while the South Orkney Islands showed the lowest abundance compared to other areas. Ice coverage was the main environmental driver shaping the abundance pattern and assemblage structure of peracarids and the latter were positively correlated with ice coverage and chlorophyll-a concentration. We propose that the positive correlation between sea ice and peracarid abundances is likely due to phytoplankton blooms triggered by seasonal sea ice melting, which might increase the food availability for benthos. Variations in ice coverage extent and seasonality due to climate change would strongly influence the abundance and assemblage structure of benthic peracarids.

中文翻译：

---

南大洋和威德尔海大西洋区底栖真甲壳类动物的丰度和分布格局

气候变化正在影响南大洋 (SO) 的一些环境变量，这将对海洋生物多样性产生影响。Peracarid 甲壳类动物是 SO 底栖动物的主要和物种最丰富的群体之一。迄今为止，我们对环境变量在 SO 的 peracaid 组合中塑造丰度和物种组成的影响的知识是有限的，并且关于冰覆盖是未知的。我们研究的目的是评估海冰覆盖率、叶绿素-a 和浮游植物浓度对棘皮动物丰度、分布和组合结构的影响。此外，还评估了其他物理参数对棘皮动物丰度的影响，包括深度、温度、盐度、沉积物类型、流速、氧气、铁、硝酸盐、硅酸盐和磷酸盐。在 SO 的大西洋部分和威德尔海的不同区域使用底栖爬行架 (EBS) 对 Peracarids 进行采样。采样区的特点是不同的冰覆盖情况（无冰的南奥克尼群岛、季节性冰覆盖的菲尔希纳海槽和南极半岛东部，包括以前被常年冰架覆盖的古斯塔夫王子海峡）。共收集到 64766 只棘皮动物，并按目级别进行鉴定，包括五目：端足纲、角足纲、角足纲、桃足纲和刺螟纲。端足类是最丰富的分类单元，占总丰度的 32%，其次是 Cumacea (31%)、Isopoda (29%)、Mysidacea (4%) 和 Tanaidacea (4%)。Filchner Trough 有最高丰度的 peracarids，而与其他地区相比，南奥克尼群岛的丰度最低。冰覆盖是塑造棘皮动物丰度模式和组合结构的主要环境驱动因素，后者与冰覆盖和叶绿素-a 浓度呈正相关。我们提出，海冰和长翅类动物丰度之间的正相关可能是由于季节性海冰融化引发的浮游植物大量繁殖，这可能会增加底栖动物的食物供应。气候变化引起的冰盖范围和季节性变化将强烈影响底栖类螨的丰度和组合结构。冰覆盖是塑造棘皮动物丰度模式和组合结构的主要环境驱动因素，后者与冰覆盖和叶绿素-a 浓度呈正相关。我们提出，海冰和长翅类动物丰度之间的正相关可能是由于季节性海冰融化引发的浮游植物大量繁殖，这可能会增加底栖动物的食物供应。气候变化引起的冰盖范围和季节性变化将强烈影响底栖类螨的丰度和组合结构。冰覆盖是塑造棘皮动物丰度模式和组合结构的主要环境驱动因素，后者与冰覆盖和叶绿素-a 浓度呈正相关。我们提出，海冰和长翅类动物丰度之间的正相关可能是由于季节性海冰融化引发的浮游植物大量繁殖，这可能会增加底栖动物的食物供应。气候变化引起的冰盖范围和季节性变化将强烈影响底栖类螨的丰度和组合结构。