Sun, Yi ， Zhang, Xiuming ， Reis, Stefan ， Chen, Deli ， Xu, Jianming ， Gu, Baojing
2021-12-21 ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021 55(卷), 24(期), (16455-16464页)
Freshwater is a scarce resource, and maintaining water quality is of great importance in dryland Australia. How water quality is affected by the dry climate and socio-economic influences in Australia remains widely unknown. Here, we find that agriculture activity dominates reactive nitrogen (N-r) emissions to water bodies. Such emissions not only contribute to deteriorating water quality in Southeastern Australia but also harm marine ecosystems, including the Great Barrier Reef, a World Natural Heritage site. A dry and warm climate reduces the share of N-r emitted directly to water bodies; however, it increases the N-r concentration in surface water due to reduced water volume, leading to a 3-fold higher water N-r concentration compared to major rivers globally, e.g., in the US or China. Business-as-usual socioeconomic development would increase the total N-r emitted to surface water by at least 43% by 2050, while effective mitigation measures could reduce N runoff by about 27%. Advanced agricultural management strategies should be considered to reduce future environmental pressures due to N runoff in Australia.