Under climate change, many Arctic coastal ecosystems receive increasing amounts of freshwater, with ecological consequences that remain poorly understood. In this study, we investigated how freshwater inputs may affect the small‐scale structure of benthic food webs in a low‐production high‐Arctic fjord (Young Sound, NE Greenland). We seasonally sampled benthic invertebrates from two stations receiving contrasting freshwater inputs: an inner station exposed to turbid and nutrient‐depleted freshwater flows and an outer station exposed to lower terrestrial influences. Benthic food web structure was described using a stable isotope approach (δ¹³C and δ¹⁵N), Bayesian models, and community‐wide metrics. The results revealed the spatially and temporally homogeneous structure of the benthic food web, characterized by high trophic diversity (i.e., a wide community isotopic niche). Such temporal stability and spatial homogeneity mirrors the high degree of trophic plasticity and omnivory of benthic consumers that allows the maintenance of several carbon pathways through the food web despite different food availability. Furthermore, potential large inputs of shelf organic matter together with local benthic primary production (i.e., macroalgae and presumably microphytobenthos) may considerably increase the stability of the benthic food web by providing alternative food sources to locally runoff‐impacted pelagic primary production. Future studies should assess beyond which threshold limit a larger increase in freshwater inputs might cancel out these stability factors and lead to marked changes in Arctic benthic ecosystems.

中文翻译：

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食物来源的多样性，营养可塑性和杂食性增强了北极高峡湾暴露于淡水输入的底栖底栖食物网的稳定性

在气候变化的影响下，许多北极沿海生态系统收到的淡水数量越来越多，其生态后果仍然鲜为人知。在这项研究中，我们调查了淡水输入如何影响低产量高北极峡湾（Young Sound，NE格陵兰岛）底栖食物网的小规模结构。我们从两个接收淡水输入相反的站点对底栖无脊椎动物进行季节性采样：一个内部站点暴露于浑浊和营养耗尽的淡水流中，另一个外部站点暴露于较低的陆地影响下。使用稳定的同位素的方法（被描述底栖食物网结构δ ¹³ C和δ ¹⁵N），贝叶斯模型和社区范围的指标。结果表明，底栖食物网的空间和时间均一性结构，具有营养丰富的特征（即广泛的社区同位素生态位）。这种时间稳定性和空间同质性反映了底栖消费者的高度营养可塑性和杂食性，尽管食物供应量不同，但仍允许维持通过食物网的若干碳途径。此外，通过为局部径流影响的中上层初级生产提供替代性食物来源，潜在的大量架子有机物投入与当地底栖初级生产（即大型藻类和大概的微型底栖动物）一起可以大大增加底栖食物网的稳定性。