Sea snail shells dissolve in increasingly acidified oceans, study shows

October 15, 2018, University of Plymouth
A heat-map demonstrating where differences are most likely to occur in shell shape among gastropods exposed to raised CO2 levels (with red indicating a greater degree of change) Credit: Ben Harvey

Shelled marine creatures living in increasingly acidified oceans face a fight for survival as the impacts of climate change spread, a new study suggests.

Researchers from the University of Tsukuba, Japan, and the University of Plymouth, UK, assessed the impact of rising carbon dioxide levels on the large predatory "triton shell" gastropod (Charonia lampas).

They found those living in regions with predicted future levels of CO2 were on average around a third smaller than counterparts living in conditions seen throughout the world's oceans today.

However there was also a noticeable negative impact on the thickness, density, and structure of their shells, causing visible deterioration to the shell surface.

Writing in Frontiers in Marine Science, scientists say the effects are down to the increased stresses placed on the species in waters where the pH is lower, which reduce their ability to control the calcification process.

And they have warned other shellfish are likely to be impacted in the same way, threatening their survival and that of other species that rely on them for food.

Dr. Ben Harvey, Assistant Professor in the University of Tsukuba's Shimoda Marine Research Center, said: "Ocean acidification is a clear threat to marine life, acting as a stressor for many marine animals. Here we found that the ability of the triton shells to produce and maintain their shells was hindered by , with the corrosive seawater making them smoother, thinner, and less dense. The extensive dissolution of their shells has profound consequences for calcified animals into the future as it is not something they can biologically control, suggesting that some calcified species might be unable to adapt to the acidified seawater if continue to rise unchecked."

A comparison of shells assessed during the research, with the top shell taken from waters with present-day CO2 levels and the bottom one from waters with future predicted levels Credit: Ben Harvey/University of Tsukuba

The research was conducted at a marine volcanic seep off the coast of Shikine-jima in Japan where carbon dioxide bubbling up through the seabed lowers seawater pH from present-day levels to future predicted levels.

Using computed tomography (CT) scanning, the scientists measured the thickness, density and structure of the shells, with shell thickness halved in areas with raised CO2 while average shell length was reduced from 178mm in sites with present day levels to 112mm.

In some cases, these negative effects left body tissue exposed and the shell casing dissolved, with the corrosive effects of acidi?cation far more pronounced around the oldest parts of the .

Jason Hall-Spencer, Professor of Marine Biology at the University of Plymouth, added: "Our study clearly shows that increasing levels cause seawater to become corrosive to shellfish. As these calcified animals are a fundamental component of coastal marine communities, ocean acidi?cation is expected to impact shellfish fisheries."

Explore further: Study shows ocean acidification is having major impact on marine life

More information: Ben P. Harvey et al, Dissolution: The Achilles' Heel of the Triton Shell in an Acidifying Ocean, Frontiers in Marine Science (2018). DOI: 10.3389/fmars.2018.00371

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9 comments

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gkam
2.6 / 5 (5) Oct 15, 2018

Deniers do not care. They are monsters like Trump, pussy-grabbers, liars, narcissists, tax cheats, and serial adulterers.
Ojorf
3.7 / 5 (9) Oct 15, 2018
How do we know these sea snails are not Chinese shills, paid to perpetuate the climate change hoax? President Trump predicted that this would happen and now it has, the molluscs are in on it.
Slimey braying Jackass Chicken Little sucker snails.
gkam
3 / 5 (4) Oct 15, 2018
I never trusted them.
rrwillsj
2.5 / 5 (2) Oct 15, 2018
A possible bit of fall-out from the kiss if sea-snail shells?

Hermit Crabs will suffer a severe housing shortage. May have to timeshare or even hot-bunk! Name change eventually? To Hoovertrumpville Crabs?
Estevan57
3 / 5 (2) Oct 16, 2018
LOL Hoovertrumpville crabs.
gkam
3 / 5 (2) Oct 16, 2018
Actually, since these are lower on the food chain than us, and includes the copepods even lower down, it threatens our supply of food and oxygen.

No joke is worth that.
rrwillsj
not rated yet Oct 16, 2018
Oh gkam. it is our basic monkey instinct to go out laughing. Screeching defiance as the cold, dark night of self-inflicted extinction sweeps us into the trashbin of eternity.
howhot3
not rated yet Oct 16, 2018
Besides; LOL Hoovertrumpville crabs. Basically softshell crabs without the molting.
dvoit1944
not rated yet Nov 06, 2018
I am not clear on the chemistry of shells but if calcium carbonate chemistry is the same as an aqueous solution, this is puzzling. The concentration of CO2 should increase CO3-- and the result would be less solubility of calcium carbonate, not more. The solubility product should be a constant and an increase in CO3-- results in a decrease of Ca++. I assume the stuff exiting a volcanic vent has a lot of acidic components and may well cause this. Suggesting only CO2 is at fault leaves me wondering what other anions are present and how this actually happens. It might be premature to blame CO2.

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