Could Europe's coastal wetlands address our climate change concerns?

When it comes to fighting climate change, we often think about planting more trees. But coastal wetlands capture and store carbon even better than tropical forests. 

In this episode of Ocean, we travel to Ireland, the Netherlands and Italy to find out if we are overlooking a climate change solution that's right under our feet.

With every high tide, the waves of the Atlantic wash over Derrymore Island marshes. It's more than a scenic view; it's a natural carbon sink. A team from University College Dublin is here to study just how well these marshes help remove carbon from the air.

"Salt marshes are a tidally inundated habitat, so they're low-lying, and the plants that live here — they need to be able to tolerate the salty conditions and also the waterlogged conditions, that actually make salt marshes good at storing carbon," explained Grace Cott, a coastal wetland ecologist at University College Dublin.

All plants capture CO2 to grow, but on dry land, they release most of that carbon back into the air when they decompose.

Marsh grasses are different: saturated by salty water, they're less likely to break down, keeping their captured carbon in the soil.

"We're trying to really get a sense of exactly how much carbon is being stored in this habitat, and then we can propose different ways of managing these habitats so that they can continue to store carbon," Grace Cott added.

The key tool for this research is the eddy covariance tower — a sensitive instrument that tracks the exchange of gases between the soil and the atmosphere, indicating the actual amount of carbon the marsh is capable of storing.

"What we calculate here is the fluxes of carbon dioxide and water vapour," revealed Lisa Jessen, a researcher in saltmarsh ecology at