Since 2003, ArcticGRO has provided essential data about the biogeochemistry and discharge of the largest Arctic rivers. These rivers transport huge quantities of water and constituents from the continents to the Arctic Ocean, and changes in Arctic river discharge and chemistry reflect changes occurring on land and lead to changes in the chemistry, biology, and circulation of the receiving coastal and ocean waters. Thus, understanding a rapidly changing Arctic requires an understanding of the Arctic's rivers, which is exactly what ArcticGRO aims to provide.