Iron (Fe) is an important element in aquatic ecosystems worldwide because it is intimately tied with multiple abiotic and biotic phenomena. Here, we give a survey of manifold influences of Fe, and the key factors affecting it in the boreal catchments and their waters. It includes the perspectives of biogeochemistry, hydrology, ecology, and river basin management. We emphasize views on the dynamics and impacts of different forms of Fe in riverine environments, including organic colloids and particles, as well as inorganic fractions. We also provide perspectives for land use management in boreal catchments and suggest guidelines for decision making and water management. Based on our survey, the main emphases of water protection and management programs should be (i) prevention of Fe mobilization from soil layers by avoiding unnecessary land-use activities and minimizing soil disturbance in high-risk areas; (ii) disconnecting Fe-rich ground water discharge from directly reaching watercourses; and (iii) decreasing transport of Fe to watercourses by applying efficient water pollution control approaches. These approaches may require specific methods that should be given attention depending on catchment conditions in different areas. Finally, we highlight issues requiring additional research on boreal catchments. A key issue is to increase our understanding of the role of Fe in the utilization of DOM in riverine food webs, which are typically highly heterotrophic. More knowledge is needed on the metabolic and behavioral resistance mechanisms that aquatic organisms, such as algae, invertebrates, and fish, have developed to counter the harmful impacts of Fe in rivers with naturally high Fe and DOM concentrations. It is also emphasized that to fulfil the needs presented above, as well as to develop effective methods for decreasing the harmful impacts of Fe in water management, the biogeochemical processes contributing to Fe transport from catchments via rivers to estuaries should be better understood.

铁 (Fe) 是全球水生生态系统中的重要元素，因为它与多种非生物和生物现象密切相关。在这里，我们对 Fe 的多种影响进行了调查，以及在北方集水区及其水域中影响它的关键因素。它包括生物地球化学、水文学、生态学和流域管理的观点。我们强调对河流环境中不同形式 Fe 的动力学和影响的看法，包括有机胶体和颗粒，以及无机部分。我们还提供了北方集水区土地利用管理的观点，并为决策和水资源管理提出了指导方针。根据我们的调查，水保护和管理计划的主要重点应该是 (i) 通过避免不必要的土地利用活动和尽量减少高风险地区的土壤扰动，防止铁从土壤层迁移；(ii) 切断富铁地下水排放直接进入河道；(iii) 通过应用有效的水污染控制方法减少铁向水道的传输。这些方法可能需要特定的方法，应根据不同地区的流域条件予以注意。最后，我们强调需要对北方集水区进行额外研究的问题。一个关键问题是增加我们对 Fe 在利用河流食物网中 DOM 中的作用的理解，这些食物网通常是高度异养的。需要更多关于水生生物（如藻类、无脊椎动物和鱼类）的代谢和行为抵抗机制的知识，以应对自然高 Fe 和 DOM 浓度的河流中 Fe 的有害影响。还需要强调的是，为了满足上述需求，并开发有效的方法来减少铁在水管理中的有害影响，应该更好地了解促进铁从集水区通过河流运输到河口的生物地球化学过程。