Table_1_Abundance and Distributional Patterns of Benthic Peracarid Crustaceans From the Atlantic Sector of the Southern Ocean and Weddell Sea.xlsx

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.

气候变化正影响南大洋（Southern Ocean, SO）的多项环境变量，并将对其海洋生物多样性造成冲击。囊虾类甲壳动物（Peracarid crustaceans）是南大洋底栖生物中占主导且物种多样性最高的类群之一。迄今为止，学界关于环境变量如何塑造南大洋囊虾类群落的丰度与物种组成的认知仍较为有限，而针对海冰覆盖的相关研究更是空白。本研究旨在探究海冰覆盖、叶绿素a（chlorophyll-a）及浮游植物浓度对囊虾类丰度、分布格局与群落结构的影响。此外，本研究还评估了其他物理化学参数对囊虾类丰度的影响，涵盖水深、水温、盐度、沉积物类型、流速、溶解氧、铁、硝酸盐、硅酸盐及磷酸盐。研究团队使用底栖生物拖网（epibenthic sledge, EBS）在南大洋大西洋扇区的多个区域及威德尔海开展囊虾类采样。采样区域涵盖不同海冰覆盖类型的海域：无冰的南奥克尼群岛、季节性海冰覆盖的菲尔希纳海槽，以及曾被永久性冰架覆盖的南极半岛东部区域（含古斯塔夫王子海峡）。本次研究共采集到64766头囊虾类个体，鉴定至目级阶元，涵盖5个目：端足目（Amphipoda）、涟虫目（Cumacea）、等足目（Isopoda）、糠虾目（Mysidacea）及塔奈水虱目（Tanaidacea）。端足目为丰度最高的类群，占总个体数的32%；其次为涟虫目（31%）、等足目（29%）、糠虾目（4%）与塔奈水虱目（4%）。菲尔希纳海槽的囊虾类丰度最高，而南奥克尼群岛的丰度则为所有采样区域中最低。海冰覆盖是塑造囊虾类丰度格局与群落结构的核心环境驱动因子，囊虾类丰度与海冰覆盖度及叶绿素a浓度呈显著正相关。研究推测，海冰与囊虾类丰度间的正相关关系，可能源于季节性海冰融化引发的浮游植物水华，此举可提升底栖生物的食物可获得性。气候变化引发的海冰覆盖范围与季节节律变化，将显著影响底栖囊虾类的丰度与群落结构。