Freshwater coastal erosion impacts global carbon stores; wetlands have high carbon storage rates but can lose carbon much faster than accumulate it

Shoreline erosion can transform freshwater wetlands from carbon-storage pools to carbon sources

Read ScienceDaily coverage here

….Wave action and high water levels sweep away soils and plants at a rate much higher than nature can replace them. An accurate measurement of this carbon budget imbalance may help better prioritize coastal management efforts and improve global carbon-cycle mode.

Freshwater wetlands account for as much as 95 percent of all wetlands — freshwater and marine — and have one of the highest carbon-storage rates of any environment, the researchers said (see here reporting that wetlands just in continental US hold ~12 billion tons of C).

The study found a large mismatch between how long it takes the carbon to accumulate versus how long it takes to erode, Braun said. “Ten percent of what took 500 years to accumulate disappeared in a six-month period. This wetland — or carbon reservoir, if you are looking at it from a carbon-budget perspective — took a permanent ding. The rate at which wetlands may rebuild can never catch up to the rate at which they were eroded.”