International
THE CANADIAN PRESS/Nathan Denette. NSD/

Canada - Estuaries more efficient at capturing carbon than some forests: B.C. study

Estuaries edged by tall grasses and wildflowers that are home to birds, crabs, tiny fish and other wildlife are more effective than young coastal forests at capturing and storing carbon dioxide, says a study.

Estuaries edged by tall grasses and wildflowers that are home to birds, crabs, tiny fish and other wildlife are more effective than young coastal forests at capturing and storing carbon dioxide, says a study.

The Cowichan Estuary on Vancouver Island captures and stores about double the amount of carbon compared with an actively growing 20-year-old Pacific Northwest forest of the same area, said the recently published study in the journal Frontiers in Marine Science.

Tristan Douglas, a University of Victoria graduate and lead author, said so-called blue carbon, or the greenhouse gas stored in marine and coastal ecosystems, is different from those held on the land.

READ MORE: Emperor Penguins could be extinct in ‘the next 30, 40 years’ due to climate change

He said saltwater estuaries, where fresh water meets the ocean, hold as much carbon as forests even though they represent just a small fraction of the area.

“The plants and algae that grow on the sea floor surface and in the water, they’re very efficient at taking carbon dioxide and converting it into organic molecules,” he said.

Trees sequester greenhouse gases but they have a limited lifespan, die, decompose and are converted back into carbon dioxide, he said.

In estuaries, Douglas said, carbon is quickly converted into plant-based material, buried in the sediment and becomes oxygen-free just a few millimetres under the surface.

“So, it’s very likely that the deposited organic matter won’t get readmitted as carbon dioxide back into the atmosphere.”

Read more.