One of the important functions of a river is to remove some of the pollution that can end up in the water, like lawn fertilizers and harmful bacteria, before that water reaches sensitive downstream ecosystems such as estuaries and oceans. Research from the University of New Hampshire has found that watershed size plays a major role in a river network's ability to do this work. The findings further the understanding of which estuaries and coastal areas will be more impacted by human development in their watersheds and also casts a light on the intricacies of the global carbon cycle.