US Estuaries Struggling to Perform Under Increasing Stress

Human and climate-related stressors are taking their toll on the nation's 28 National Estuarine Research Reserves (NERR), according to a NOAA report, putting both human safety and sensitive ecosystems at risk

As the place where a river meets the sea, estuaries harbor unique communities of life due to their mixture of fresh and salty water. As one of the most productive ecosystems in existence, many animals rely on estuaries for food and a place to nest and breed.

Humans, too, rely on the natural formations with 22 of the world's 32 largest cities located on one. Not only do the they act as a buffer from the impacts of coastal storms and sea level rise, but many industries are based on their success, be it recreational, fishing or otherwise.

Which is why NOAA is sounding the alarm after a recent check-up on the largest estuaries throughout the country showed that many are struggling to perform under the weight of ever-increasing stress placed on them through a changing climate and other, more directly-related anthropogenic influences.

Among the greatest stressors, the researchers found, were toxic pollutants, storm impacts, invasive species, habitat fragmentation, sedimentation and shoreline erosion. The biggest contributors to these were residential development, land use, population growth, wastewater treatment and sea level rise.

Furthermore, the report examines the degree of social sensitivity to climate change, as indicated by higher employment based on local natural resources, in addition to lower per capita income, median home values, higher percentages of minority populations and a higher percentage of individuals lacking a high school education. In doing so, the study's authors determined that those living in the southern portions of the East and West coasts of the United States, the Gulf of Mexico and Alaska faced the greatest threat to livelihood and overall welfare in regards to ongoing climate change.

Finally, the report looks at biophysical sensitivity, or an estuary's relationship between annual spring atmospheric temperatures, rainfall and water quality. As a result, the authors found that those areas facing the greatest amount of risk in regards to temperature change were in the Great Lakes, Gulf of Mexico, Mid-Atlantic and Northeast regions of the country. Meanwhile, the Gulf of Mexico, parts of the Mid-Atlantic, Southeast, California and Oregon were found to be at greatest risk of sea level rises.

In particular, the study points to four estuaries that, when it comes to sensitivity to climate change, stand out from their peers, including the Sapelo Island NERR in Georgia, ACE Basin NERR in South Carolina, Waquiot Bay NERR in Massachusetts and the Tijuana River NERR on the California-Mexico border.

As the first comprehensive examination of the climate sensitivity of US estuaries, the study, according to its authors, is merely one step in a long road of developing a better understanding of the nature and fate of these key ecosystems, and what that means for all those involved. Going forward, they write, "a more purposeful and thorough analysis of extreme sensitivity should be conducted to examine these types of impacts in more detail."