Research reveals starfish 'dissolved' by carbon dioxide

By: Clare Fischer
Date posted: 19 February 2018

Scientists say bursts of carbon dioxide from industry and land run off could cause irreparable damage to marine ecosystems.

Starfish
© Paul Naylor

Our continued monitoring of the site directly after the carbon dioxide exposure found recovery was comparably slow, which raises concern about the ability of these systems to ‘bounce back’ after repeated acute carbon dioxide events.

Heidi Burdett,
Heriot-Watt University research fellow,

Tests were carried out during a four-day experiment at Loch Sween on Scotland’s west coast, to find out how whole marine ecosystems respond to short-term carbon dioxide exposure.

The results showed that calcified organisms such as the coralline algae and starfish were dissolving.

Researchers from Heriot-Watt University in Edinburgh and Glasgow University pumped water enriched with carbon dioxide into chambers placed over the coralline algal ecosystem and monitored the community’s response before, during and after exposure.

Heidi Burdett, Heriot-Watt University research fellow, said: “We found that there was a rapid, community-level shift to net dissolution, meaning that within that community, the skeletons of calcifying organisms like starfish and coralline algae were dissolving.

“If you think of pulses of carbon dioxide being carried on the tide to a particular site, it’s like a flash flood of carbon dioxide.

“Our continued monitoring of the site directly after the carbon dioxide exposure found recovery was comparably slow, which raises concern about the ability of these systems to ‘bounce back’ after repeated acute carbon dioxide events.”

Coralline algal ecosystems are very common along the west coast of Scotland, but are found in all the world’s coastal oceans. They act as nurseries for important catches like scallops, cod and pollock.

“Since coralline algae are highly calcified, we knew they would probably be quite sensitive to carbon dioxide,” said Heidi Burdett.

Dr Laura Foster is the MCS Head of Clean Seas and says that coastal algae are really important within coastal ecology, but they are facing increasing numbers of challenges from pollution: “Increased CO2 levels in the atmosphere result in it becoming increasingly difficult for them to calcify. Intertidal zones experience huge fluctuations in carbon dioxide making it a challenging environment for organisms, but are key habits for larvae. This has long term implications for the survival of a baseline species. We need to work on reducing our CO2 footprint- if we all take small actions then we can make significant reductions to CO2.”

In Scotland, the team concluded that more research is necessary and that carbon dioxide exposure should be taken into account by policymakers: “If a local authority or government agency is deciding 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, ” said Heidi Burdett.

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