Carbon capture

Scotland: Oyster reefs could off-set carbon levels

Oyster reefs could help Scotland reach net-zero carbon emissions goals.

Researchers are testing the carbon storage potential of oyster reefs in Scottish waters.

30% of carbon emissions released into the atmosphere dissolve into oceans, creating carbonic acid. The effect does not only serve to raise water temperature levels but also contributes to greater acidity in marine environments.

Increased ocean acidity may hinder corals, which provide homes for various marine organisms, to build skeletons.

Concerns have also been rife as greater levels of calcium carbonate in water could dissolve the carbon shells of marine organisms. This is a potential threat but unlikely to affect said marine wildlife anytime soon as the required carbon saturation level for this scenario to come to pass is still centuries in the making.

On the other hand, species such as lobsters, mussels, clams and oysters require a certain level of carbon is necessary to create their calcium carbonate shells-a lack of carbon forces said organisms to expend more energy to build their shells, rendering them pitted and weak.

In oysters, carbon contributes to 12% of overall shell mass.

Scientists at Edinburgh’s Heriot-Watt University are now conducting research into the carbonate shells of these molluscs, having reinvigorated native oyster beds that went extinct on the shores of the Dornoch Firth a century ago due to overfishing.

Aiming to populate the waters with 4 million oysters, the researchers are keen on discovering to what extent these shellfish can be used for carbon capture purposes.

A part of the Dornoch Environment Enhancement Project (DEEP) and pioneered by Glenmorangie Distillery, the most prominent distillery in the country, the initiative aims to enhance biodiversity in the area as well as act in tandem with an anaerobic digestion plant already built by the distillery. Said plant removes 95% of wastewater solids from wastewater released by the distillery-the oyster reef is intended to naturally cleanse the remaining 5% of organic waste.

Professor Bill Sanderson of Herriot-Watt University said: “We are still uncovering exactly how much of a game changer this can be but we’re increasingly focusing our research on delving deeper into the role of the oyster reef as a carbon store. It’s great to think that the Dornoch Firth can contribute as a global exemplar for helping to mitigate climate change, especially as we run up to COP26 being held here in Scotland.”