Over the last centuries, human activities have exerted increasing pressures on the environment, leading to drastic alterations in the functioning of freshwater bodies (e.g., eutrophication). Global biogeochemical models have proven crucial to investigate interactions between humans, hydrology, and water quality of surface fresh waters. However, most do not account for high‐resolution spatial and temporal variability within watersheds, and they typically lack any representation of benthic dynamics that can drive pollution legacy effects. We present here the Integrated Model to Assess the Global Environment‐Dynamic Global Nutrient Model (IMAGE‐DGNM), which couples global, spatially explicit hydrology and integrated assessment models with process‐based biogeochemistry in surface fresh waters. The new Dynamic In‐Stream Chemistry (DISC) module calculates advective transport from headwaters to estuaries, processes in the water column and in bed sediments, as well as the exchanges between these two compartments. As application examples of IMAGE‐DGNM, we simulate sediment dynamics and nitrogen cycling in two large river basins. We assess in‐stream concentration time series at specific locations, and identify governing processes in transfers along the aquatic continuum. Results highlight the importance of benthic dynamics in watersheds highly perturbed by damming. The implementation of such dynamics within IMAGE‐DGNM allows for including the temporal effect of pollution legacies in large scale water quality studies and shifts in pollutant speciation along river continua. This new framework therefore incorporates new features for large basin to global scale studies that are crucial to better predict the effects on receiving ecosystems and evaluate future environmental management pathways.

中文翻译：

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利用IMAGE‐DGNM框架对大型流域地表淡水中基于过程的生物地球化学动力学进行建模

在过去的几个世纪中，人类活动对环境施加了越来越大的压力，导致淡水水体功能发生急剧变化（例如富营养化）。事实证明，全球生物地球化学模型对于研究人与水之间的相互作用以及地表淡水的水质至关重要。但是，大多数都不能说明流域内的高分辨率时空变化，而且它们通常缺乏能驱动污染遗留效应的底栖动力的任何表示。我们在此介绍用于评估全球环境动态全球营养模型（IMAGE-DGNM）的综合模型，该模型将全球，空间明确的水文学和综合评估模型与地表淡水中基于过程的生物地球化学相结合。新的动态流化学（DISC）模块计算从上游源头到河口的平流输运，水柱和床底沉积物的过程，以及这两个舱室之间的交换。作为IMAGE‐DGNM的应用示例，我们模拟了两个大型流域的沉积物动力学和氮循环。我们评估特定位置的河内集中时间序列，并确定沿水生生物连续体转移的治理过程。结果突显了在大坝扰动下的流域底栖动力学的重要性。在IMAGE-DGNM中实施这种动力学可以将污染遗留的时间效应纳入大规模水质研究中，并沿河流连续性迁移污染物形态。