Vulnerability of estuarine systems in the contiguous United States to water quality change under future climate and land-use

Changes in climate and land-use and land-cover (LULC) are expected to
influence surface water runoff and nutrient characteristics of estuarine
watersheds, but the extent to which estuaries are vulnerable to altered
nutrient loading under future conditions is poorly understood. The present
work aims to address this gap through the development of a new
vulnerability assessment framework that accounts for (1) estuarine
exposure to projected changes in total nitrogen (TN) and total phosphorus
(TP) loads as a function of LULC and climate change under several
scenarios to altered nutrient loads, (2) sensitivity (i.e., how
responsive estuaries are to altered nutrient loads), and (3)
adaptive capacity (i.e., how the socio-ecological system can use existing
resources to reduce the impacts associated with increased exposure). The
framework was applied to 112 estuaries and their contributing watersheds
across the contiguous U.S., specifically to look at regional variability
in estuarine vulnerability to nutrient loading. Study findings
revealed that the largest increases in estuarine nutrient loads are
expected in the North and South Atlantic regions and eastern Gulf of
Mexico, while the lowest increase is expected in the North and South
Pacific regions and the western Gulf of Mexico. However, the North
Atlantic and the South Pacific had the highest adaptive capacity, which
could potentially counteract the effects of LULC and climate change on
nutrient loads. Our findings illustrate the benefits of integrating
natural and socio-ecological factors to identify opportunities to develop
adaptation plans and policies to mitigate ecological degradation in
vitally important estuaries. A web-based application has
been developed to visualize and download the data.