Recent research indicates that constructed wetlands are effective at capturing carbon in their initial years, a crucial factor in combating climate change. However, this capacity tends to decline as the wetlands evolve.
In the study, scientists evaluated soil core samples from two constructed freshwater wetlands, comparing them to data collected over 29 years from these sites to assess how effectively these man-made wetlands store carbon as they age.
The results indicated that both wetlands sequestered similar amounts of carbon throughout the years, yet there has been no significant net gain or loss in carbon storage after the 15th year.
The researchers highlighted the impressive role wetlands play in carbon sequestration.
“Wetlands are often regarded as the kidneys of our ecosystem due to their natural water purification capabilities and efficient carbon storage,” explained Jay Martin, a distinguished professor in food, agricultural, and biological engineering at The Ohio State University and co-author of the study. “In our efforts to address climate change, they also serve as habitats for many vital species.”
The research team utilized data from the Schiermeier Olentangy River Wetland Research Park (ORWRP), which has provided extensive environmental data for over thirty years, making it ideal for long-term studies.
Earlier research on the park indicated an increase in soil carbon levels. However, by conducting precise measurements during the wetland’s 29th year, Martin’s team concluded that carbon sequestration capabilities lessen as the wetlands mature.
The findings were published in the journal Ecological Engineering.
Currently, the wetlands have established a stable ecological framework, a balance that is not anticipated to change in the near future.
“In the initial phase after constructing a wetland, rapid plant growth is the primary driver of carbon sequestration,” stated Daniel Ruane, a former master’s student in ecological engineering and the lead author. “However, unlimited growth is not sustainable.”
Despite the limitations on the amount of atmospheric carbon that artificial wetlands can store effectively, their rates of carbon sequestration still surpass those of many other ecosystems, positioning them as a viable solution in the fight against climate change, remarked Ruane.
Future investigations at the ORWRP will likely focus on the variety of plant communities thriving in the wetlands and analyze methane emissions to understand how long these areas can remain effective as carbon sinks.
“The advantages wetlands offer are increasingly recognized,” noted Martin. “Our results underline the importance of viewing these ecosystems more favorably than ever before.”
Over the past few centuries, more than half of the world’s natural wetlands have vanished due to rising urban and agricultural development. This loss has adversely affected ecosystem services across the United States, particularly in the Midwest, according to Martin.
In Ohio, for instance, the anticipated loss of wetlands may approach 90%, threatening essential processes such as water quality enhancement and flood management.
This situation underscores the need for policymakers to prioritize the creation and preservation of wetland ecosystems, Ruane emphasized.
“If we begin to develop and restore more wetlands now, it could alleviate many issues in the future,” he asserted.
The study’s co-authors include Michael Brooker and William Mitsch from Ohio State, Blanca Bernal from Greencollar US Inc., Chris Anderson from Auburn University, and Robert Nairn from the University of Oklahoma.
