Carbon dioxide ‘pulses’ threaten Scotland’s coralline algal reefs

Scotland’s marine ecosystems may be more sensitive to carbon dioxide than previously thought, and could be damaged irreparably by the CO2 ‘pulses’ created by industrial activities, land run off or natural tidal processes.

Until now, scientists had only tested the effect of high CO2 on individual plants and animals, meaning very little was known about how whole marine ecosystems respond to sudden influxes of CO2.

A team of marine scientists from the University of Glasgow and Heriot-Watt University conducted an experiment on the west coast of Scotland to measure the community response to short-term CO2 exposure.

The team pumped water enriched with CO2 into chambers placed over the coralline algal ecosystem and monitored the community’s response before, during and after CO2 exposure. The experiment revealed that acute CO2 exposure led to net dissolution: calcified organisms like the coralline algae and star fish were dissolving.

Dr Nick Kamenos, Senior Lecturer at the University of Glasgow said: “Coralline algal are common in Scotland and change the shape of the seabed; this makes them very important for providing homes to juvenile species of commercial importance such as scallops.”

“However, the algae are also sensitive to increases in carbon dioxide concentrations such as those used in this experiment. This means that as a whole community, they and the services they provide may be at risk for abrupt increases in carbon dioxide. We found that there was a sudden, community-level, shift to overall dissolution, meaning that within that community, the skeletons of calcifying organisms like the coralline algae and associated star fish were dissolving.”

Dr Kamenos and his team designed this experiment to replicate how complex real ecosystems respond to global change and believe more research is necessary to understand how such marine ecosystems respond to short-term and long-term CO2 exposure.

Dr Heidi Burdett, Research Fellow at Heriot-Watt University’s Lyell Centre for Earth and Marine Science and Technology, co-authored the paper.

Dr Burdett and her team believe more research is necessary to understand how marine ecosystems respond to short-term and long-term CO2 exposure, and that it should be taken into account by policymakers.

“If a local authority or government agency is deciding about the location of a new fish farm, forestry or carbon capture site, we should be looking at what marine ecosystems are nearby, and the potential for those ecosystems to be impacted by the new activities as a whole, rather than focusing on the impact on individual organisms."

First published: 19 February 2018