Food production for a growing world population relies on application of fertilisers and pesticides on agricultural lands. However, these substances threaten surface water quality and thereby endanger valued ecosystem services such as drinking water supply, food production and recreational water use. Such deleterious effects do not merely arise on the local scale, but also on the regional scale through transport of substances as well as energy and biota across the catchment. Here we argue that aquatic ecosystem models can provide a process-based understanding of how these transports by water and organisms as vectors affect – and are affected by – ecosystem state and functioning in networks of connected lakes. Such a catchment scale approach is key to setting critical limits for the release of substances by agricultural practices and other human pressures on aquatic ecosystems. Thereby, water and food production and the trade-offs between them may be managed more sustainably.

不断增长的世界人口的粮食生产依赖于在农地上施用肥料和杀虫剂。但是，这些物质威胁着地表水的质量，从而危及宝贵的生态系统服务，例如饮用水供应，食品生产和娱乐用水。这种有害影响不仅会在地方范围内产生，而且还会通过跨集水区的物质以及能源和生物群的运输而在区域范围内产生。在这里，我们认为，水生生态系统模型可以提供基于过程的理解，以作为媒介的水和生物的这些运输如何影响生态系统状态以及在相连的湖泊网络中的功能，并受其影响。这种集水规模方法对于为农业实践和其他人类对水生生态系统的压力释放物质设定关键限制至关重要。由此，可以更可持续地管理水和粮食生产以及它们之间的权衡。