Marine soft sediments are some of the most widespread habitats in the ocean, playing a vital role in global carbon cycling, but are amongst the least studied with regard to species composition and ecosystem functioning. This is particularly true of the Polar Regions, which are currently undergoing rapid climate change, the impacts of which are poorly understood. Compared to other latitudes, Polar sediment habitats also experience additional environmental drivers of strong seasonality and intense disturbance from iceberg scouring, which are major structural forces for hard substratum communities. This study compared sediment assemblages from two coves, near Rothera Point, Antarctic Peninsula, 67°S in order to understand the principal drivers of community structure, for the first time, evaluating composition across all size classes from mega- to micro-fauna. Morpho-taxonomy identified 77 macrofaunal species with densities of 464–16,084 individuals m−2. eDNA metabarcoding of microfauna, in summer only, identified a higher diversity, 189 metazoan amplicon sequence variants (ASVs) using the 18S ribosomal RNA and 249 metazoan ASVs using the mitochondrial COI gene. Both techniques recorded a greater taxonomic diversity in South Cove than Hangar Cove, with differences in communities between the coves, although the main taxonomic drivers varied between techniques. Morphotaxonomy identified the main differences between coves as the mollusc, Altenaeum charcoti, the cnidarian Edwardsia sp. and the polychaetes from the family cirratulidae. Metabarcoding identified greater numbers of species of nematodes, crustaceans and Platyhelminthes in South Cove, but more bivalve species in Hangar Cove. There were no detectable differences in community composition, measured through morphotaxonomy, between seasons, years or due to iceberg disturbance. This study found that unlike hard substratum communities the diversity of Antarctic soft sediment communities is correlated with the same factors as other latitudes. Diversity was significantly correlated with grain size and organic content, not iceberg scour. The increase in glacial sediment input as glaciers melt, may therefore be more important than increased iceberg disturbance.

中文翻译：

---

南极浅层底栖生物群落的时空动态：气候变化下的生态驱动力

海洋软沉积物是海洋中最广泛的栖息地，在全球碳循环中起着至关重要的作用，但在物种组成和生态系统功能方面却是研究最少的物种之一。极地地区尤其如此，这些极地地区目前正在经历迅速的气候变化，对其影响的了解甚少。与其他纬度相比，极地沉积物栖息地还经历了额外的环境驱动因素，这些因素具有强烈的季节性和冰山冲刷的强烈干扰，而冰山冲刷是坚硬的底层群落的主要结构力。这项研究首次比较了南极半岛罗瑟拉角（67°S）附近两个海湾的沉积物组合，以便首次了解群落结构的主要驱动因素，评估从大型动物到微型动物的所有规模类别的组成。形态分类学确定了77个大型动物物种，密度为464–16,084个个体m-2。仅在夏季，微动物的eDNA metabarcoding鉴定出较高的多样性，使用18S核糖体RNA鉴定了189个后生动物扩增子序列变体（ASV），使用线粒体COI基因鉴定了249个后生动物ASV。两种技术在南湾的分类学多样性都比飞机库更大，海湾之间的群落也有所不同，尽管主要的分类学驱动因素在两种技术之间有所不同。形态分类学将小海湾之间的主要区别定为软体动物，炭疽菌，刺胞小爱德华氏菌。和c科的多毛poly。元条形码识别出更多种类的线虫，南湾有甲壳类和侧柏类，而在机库湾有更多的双壳类。在季节，年份之间或由于冰山干扰，通过形态分类学测量的群落组成没有可检测的差异。这项研究发现，与坚硬的底层群落不同，南极软沉积物群落的多样性与其他纬度具有相同的因素。多样性与谷物大小和有机物含量显着相关，而不是与冰山冲刷有关。因此，随着冰川融化，冰川沉积物输入的增加可能比增加的冰山扰动更为重要。这项研究发现，与坚硬的底层群落不同，南极软沉积物群落的多样性与其他纬度具有相同的因素。多样性与谷物大小和有机物含量显着相关，而不是与冰山冲刷有关。因此，随着冰川融化，冰川沉积物输入的增加可能比增加的冰山扰动更为重要。这项研究发现，与坚硬的底层群落不同，南极软沉积物群落的多样性与其他纬度具有相同的因素。多样性与谷物大小和有机物含量显着相关，而不是与冰山冲刷有关。因此，随着冰川融化，冰川沉积物输入的增加可能比增加的冰山扰动更为重要。