Coastal upwelling that occurs in the eastern Arabian Sea (EAS) drive the complex dynamics of the food chain. Macrofauna plays a key role in the functioning of coastal ecosystems, but few studies explored the taxonomic and functional patterns of macrofaunal communities under the influence of upwelling. These patterns have been investigated in this study by sampling macrofauna and environmental variables during March–December 2012 across six depths (13–100 m) over the continental shelf off Kochi, south EAS. Upwelling, set over outer shelf prior to March, occupies the entire shelf by May, peaked during June–July and withdrew rapidly by September.

A total of 203 macrofaunal taxa were collected in this study. Multivariate analysis revealed that the macrofaunal composition showed a spatiotemporal variation. Taxonomic diversity increases from nearshore to mid shelf whereas abundance and biomass decreased. Macrobenthic functioning, assessed through Biological Trait Analyses, displayed similar trait modalities between depths and seasons but abundance driven differences in trait expression revealed important habitat filtering. Increase in organic matter and decrease in dissolved oxygen influenced by upwelling and the spatial variation in sediment texture were the strongest drivers of the macrofaunal taxonomic pattern. We suggest that taxonomic and biological trait information needs to be considered in ecological studies as it provides a better understanding of how biodiversity responds to and interacts with environmental changes.

发生在阿拉伯海东部 (EAS) 的沿海上升流推动了食物链的复杂动态。大型动物群在沿海生态系统的功能中起着关键作用，但很少有研究探讨在上升流影响下大型动物群落的分类和功能模式。本研究通过在 2012 年 3 月至 12 月期间在 EAS 南部高知附近大陆架上的六个深度（13-100 m）采样大型动物和环境变量来研究这些模式。上升流在 3 月之前设置在外陆架上，到 5 月占据整个陆架，在 6 月至 7 月达到顶峰，并在 9 月迅速撤退。

本研究共收集了 203 个大型动物类群。多变量分析表明，大型动物群落组成呈现出时空变化。从近岸到中陆架，分类多样性增加，而丰度和生物量减少。通过生物特征分析评估的大型底栖动物功能在深度和季节之间显示出相似的特征模式，但特征表达的丰度驱动差异揭示了重要的栖息地过滤。受上升流影响的有机质增加和溶解氧减少以及沉积物质地的空间变化是大型动物分类模式的最强驱动因素。