They can often be overlooked as a wasteland left behind by receding tides, but researchers from the University of Victoria say it could be key in climate mitigation.
Estuaries are bodies of water that are enclosed and have at least one river or stream flowing into them — allowing for fresh and saltwater to mix.
“They’re a really important habitat for juvenile fish and shellfish, particularly the marsh areas. They’re important for flood protection and coastal erosion protection has been long recognized,” said Kim Juniper, a professor of biology at the University of Victoria.
Along the Cowichan Estuary, plant species like marsh grass are able to capture carbon within the sediment and can store it for hundreds, possibly even thousands of years, according to a new study.
Carbon dioxide is collected as organic debris and because of the low-oxygen conditions below ground, the sediment is able to prevent carbon dioxide from being released back into the atmosphere. The study also found that Cowichan Estuary is able to capture double the amount of carbon than that of a 20-year-old forest of the same size.
“Now we got a third societal value to these estuaries. They are also a nature-based solution for climate mitigation,” said Juniper.
The study found that Cowichan Estuary is able to capture double the amount of carbon than that of a 20-year-old forest of the same size. This type of research is gaining momentum as experts look for natural solutions to fighting climate change, but human activity may damage the potential of estuaries.
“Since European settlement at about the mid-1800s, about a third of it has been reclaimed for agriculture and industrial use,” said Tristan Douglas, a University of Victoria graduate student.
According to the report, human activities have reduced the Cowichan Estuaries’ carbon capturing and storage capacity by about 30 per cent. Which is equivalent to placing 53 cars back on the road. Douglas —who is the lead author of the report — says it’s time to place protections on these bodies of water.
“We want the same care and conservation practice applied to coastal environments and estuaries as they’re applied to forests,” said Douglas.
Restoring the damage to the Cowichan Estuary is possible.
The authors says preventing further disturbance by human activity and taking on replanting efforts. could bring the estuary back to normal capacity levels. Opening dikes that prevent flooding would also allow salt marshes to return naturally and capture carbon.