Sand waves are dynamic and regular bedforms that are ubiquitous in sandy shelf seas. However, information about the ecological characteristics (e.g., benthic community structure) and their spatial variability within these habitats is very limited. To address this knowledge gap, we undertook a field campaign in summer 2017 to investigate the macrofaunal community composition of a sand wave area off Texel (Dutch part of the North Sea). Sand waves in this area were asymmetrical, with longer gentle slopes that were approximately double in length to the shorter steep slopes. The benthic distribution along the different parts of these sand waves was assessed by collecting a large number of box cores within a transect line (~1 km). We show considerable variability in the individual, biomass and taxon densities, which were all significantly higher on the steeper slopes of the sand waves. These results are consistent with the trends observed in both the abiotic parameters and video analysis that were measured in two recent studies at the same study area. Our results provide valuable insight into the small-scale patterns of variability in asymmetrical dynamic bedform environments, where gentle slopes seem to be primarily controlled by physical forces, while steep slopes are more under biotic control.

中文翻译：

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水下海景中沿不对称沙波的小型大型底栖动物群落结构

沙波是在沙质陆架海中无处不在的动态和规则的床型。然而，关于生态特征（例如，底栖群落结构）及其在这些栖息地内的空间变异性的信息非常有限。为了解决这一知识差距，我们在 2017 年夏季开展了一项实地活动，以调查特塞尔（北海的荷兰部分）附近沙浪区的大型动物群落组成。该地区的沙波是不对称的，较长的缓坡长度大约是较短的陡坡的两倍。通过在横断面线（~1 公里）内收集大量箱形岩心来评估沿这些沙波不同部分的底栖分布。我们在个体、生物量和分类群密度方面表现出相当大的变异性，在沙浪较陡的斜坡上，它们都明显更高。这些结果与最近在同一研究区域的两项研究中测量的非生物参数和视频分析中观察到的趋势一致。我们的结果提供了对不对称动态床型环境中小规模变异模式的宝贵见解，其中缓坡似乎主要受物理力控制，而陡坡则更多地受生物控制。