Natural and human pressures increasingly threatening the biodiversity and water resources of dryland rivers. Fluvial environments of Patagonia harbour high diatom diversity, but their management value is overlooked. The aim of this study is to explore the diatom distribution in surface sediments of the Chubut River and evaluate their relationship with environmental variables. In total, 243 diatom taxa were identified in 16 littoral zone sites. The physical and chemical variables independently explained the variance in diatom data, whereas sediment texture had a low influence. Conductivity, major ions (HCO₃^–, Cl^–, SO₄^2–, Na⁺, K⁺, Ca²⁺ and Mg²⁺) and pH were the main environmental drivers explaining the diatom composition. As the highlighted variables increased near the mouth, so did the relative abundances of marine–brackish taxa such as Amphora copulatoides, Sarcophagodes alfred-wegeneri, Nitzschia fonticola and Tryblionella apiculata. Meanwhile, the presence of high pollution-tolerant diatoms can be put forward to explain the river health deterioration towards downstream areas. The marine–brackish taxa found at freshwater sites reflect a weak tidal influence in the estuary compared with other coastal systems of Patagonia. This study provides valuable information to test the hypothesis on the ecological status of aquatic resources and the potential effects of climatic and hydrological changes in the area.

自然和人为压力日益威胁旱地河流的生物多样性和水资源。巴塔哥尼亚的河流环境具有较高的硅藻多样性，但其管理价值却被忽视。这项研究的目的是探索楚布特河表层沉积物中的硅藻分布，并评估它们与环境变量的关系。总共在16个沿海地带发现了243个硅藻类群。物理和化学变量独立地解释了硅藻数据的变化，而沉积物质地的影响很小。电导率，主要离子（HCO ₃ ^–，Cl ^–，SO ₄ ^2–，Na ⁺，K ⁺，Ca ²⁺和Mg ²⁺）和pH值是解释硅藻组成的主要环境驱动因素。由于突出变量口附近增加，所以没有海洋微咸水类群的相对丰度，如安芙兰copulatoides，Sarcophagodes阿尔弗雷德- wegeneri，菱形fonticola和Tryblionella红树。同时，可以提出高耐污染硅藻的存在来解释河流健康向下游地区的恶化。与巴塔哥尼亚的其他沿海系统相比，在淡水站点发现的海微咸类群反映出河口的潮汐影响较弱。这项研究提供了有价值的信息，以检验关于该地区水生资源生态状况和气候和水文变化潜在影响的假说。