New study documents declining health of coastal marshes

Scientists from Colorado State University, Georgia Southern, the University of Georgia and the University of Texas at Austin developed a model to provide an early warning and opportunity to protect an ecosystem that serves as the first line of defense against coastal flooding. By using satellite observations, the model identified vulnerable marshes along Georgia’s coast by locating declining root production – a harbinger of marsh failure.

The research, published in June in Proceedings of the National Academy of Sciences, is the first to predict broad trends in marsh deterioration using remote sensing.

“Our findings show widespread belowground decline over the past decade and suggest this is an early warning sign of marsh deterioration and loss,” said lead author Kyle Runion, a research scientist at the University of Georgia who was at UT Austin’s Marine Science Institute during the study. “By pinpointing where belowground loss is happening, we can get a head start on conservation and restoration projects to more effectively prevent marsh loss.”

Coastal marshes filter water, store carbon, act as habitat for wildlife and provide food and fishing livelihoods for people. Marshes also absorb storm surges and sea-level rise, preventing worse flooding inland.

The Georgia Coastal Ecosystems Long-Term Ecological Research Project (GCE LTER), established in 2000 to understand estuaries and their adjacent coastal wetlands and how they respond to long-term change, is based at the University of Georgia Marine Institute on Sapelo Island, Georgia, and funded by the National Science Foundation. It involves a robust program of long-term field observations, experiments, remote sensing, and modeling designed to understand wetland ecosystem functioning. GCE LTER researchers evaluate how changing conditions affect the ability of coastal ecosystems to provide food and refuge for fish, shellfish and birds, to protect the shoreline from storms, to help to keep the water clean, and to store carbon, all of which have significant implications for the US economy. In addition to research, the GCE LTER program works with teachers and students, coastal managers, citizen scientists, and the general public to enhance scientific literacy and improve our understanding of coastal ecosystems.

"We are really excited about this research as it gives us a window into the patterns and trends in below-ground biomass," said Merryl Alber, professor of marine sciences at UGA and co-author on the study. "One of the important findings of the study is that below-ground material is a better indicator of marsh resilience than aboveground – we can use areas where below-ground material is declining to provide an early warning that a marsh is vulnerable to potential loss."

Read the full news release.

Image: The sun rises over a salt marsh on Sapelo Island, Georgia, in February 2023.. Photo by Kyle Runion