Plymouth Marine Laboratories is conducting bi-monthly monitoring of the impact of the wetlands on carbon and greenhouse gas emissions (including methane and nitrous oxides).

Although not all the data gathered to date has been fully analysed, so far the wetland is releasing carbon dioxide to the estuary (CO2) (more CO2 exiting than entering).

This is expected as the wetland is still undergoing a transition from grassland – the immersed grass is rotting in the first instance, releasing CO2.

It appears that the wetland is consuming nitrate from the estuary – nitrate is an essential nutrient for plants, but too much of it can cause eutrophication, oxygen depletion and fish mortality downstream. Over the summer 2022 we had a small algal bloom in the wetland (more microalgae exiting than entering). All of these are changing gradually as the grassland transitions to a wetland.