By Andy Miller, Ph.D.
As the summer winds down, many of us return to school or work with fond memories of trips to the seashore. For me and for many others, where the ocean meets the land are places that are deeply relaxing, reminders of our connections with the natural world.
For several EPA researchers, the shores and estuaries that we value for their beauty and wonder are the sites for investigating the rich and complex ecosystems that support a multitude of species and provide us with benefits well beyond a calming walk along the shore.
Researchers have recently published results of work examining how different impacts of climate change are affecting coastal ecosystems. They demonstrate how vulnerable these natural resources are to drought, sea level rise, and other impacts of a changing climate.
Several studies looked at how the effects of climate change affected cordgrass, dominant salt marsh plants that are key to the vitality of salt marsh ecosystems in southern New England coastal wetlands. One study looked at how saltmeadow cordgrass, Spartina patens, responded to drought and sea level rise in a greenhouse set up for research. This study found that sea level rise was a threat to the long-term survival of the species. The loss of saltmeadow cordgrass would reduce the wetlands’ habitat quality, plant diversity, carbon sequestration, erosion resistance and coastal protection.
A second study examined smooth cordgrass, Spartina alterniflora, under similar stresses, and also added an additional stressor, increased levels of nitrogen in the water, an environmental pollutant resulting from agricultural runoff, urban stormwater runoff, wastewater from sewers and septic systems and other sources. EPA researchers Alana Hanson and her colleagues simulated all these plant stressors in the same research greenhouse and concluded that the effects of climate change and nitrogen runoff were likely to reduce the sustainability of salt marshes because the conditions made it more difficult for cordgrass to flourish. Without cordgrass, Atlantic coastal ecosystems would be as vulnerable as a sea turtle without its shell.
On the other side of the country, researchers on the Pacific coast have been developing an approach to evaluate how climate change is affecting coastal biodiversity. Working with experts from several federal, state, and local agencies, EPA researcher Henry Lee and his colleagues developed an approach to use environmental tolerances and other scientific information to estimate how groups of species can be expected to respond to changes in ocean temperature and acidity. Their tool, the Coastal Biodiversity Risk Assessment Tool, or CBRAT, provides an open-source platform that allows researchers and resource managers to examine the potential vulnerability of coastal Pacific fish and invertebrate species as they are impacted by climate change.
These research efforts help us understand more than just the impacts of climate change on coastal ecosystems—they also help us understand how we can respond to those changes in ways that will help protect them. Francis Bacon is credited with the saying, “The best part of beauty is that which no picture can express.” Although we see the natural beauty of our coasts and shores, the best part of that beauty may well be the unseen ways in which they nurture and support nature as a whole.
About the Author: Andy Miller is the Associate Director for Climate in EPA’s Air, Climate, and Energy Research Program that conducts research to assess the impacts of a changing climate and develop the scientific information and tools to act on climate change.
Hanson, A., R. Johnson, C. Wigand, A. Oczkowski, E. Davey and E. Markham (2016). “Responses of Spartina alterniflora to Multiple Stressors: Changing Precipitation Patterns, Accelerated Sea Level Rise, and Nutrient Enrichment.” Estuaries and Coasts: 39: 1376–1385.
Watson, E. B., K. Szura, C. Wigand, K. B. Raposa, K. Blount and M. Cencer (2016). “Sea level rise, drought and the decline of Spartina patens in New England marshes.” Biological Conservation 196: 173-181.
Lee II, H., Marko, K., Hanshumaker, M., Folger, C., and Graham, R. 2015. User’s Guide & Metadata to Coastal Biodiversity Risk Analysis Tool (CBRAT): Framework for the Systemization of Life History and Biogeographic Information. EPA Report. EPA/601/B-15/001. 123 pages.