Nav: Home

Unexpected result: Ocean acidification can also promote shell formation

January 27, 2017

Fact: More carbon dioxide (CO2) in the air also acidifies the oceans. It seemed to be the logical conclusion that shellfish and corals will suffer, because chalk formation becomes more difficult in more acidic seawater. But now a group of Dutch and Japanese scientists discovered to their own surprise that some tiny unicellular shellfish make better shells in an acidic environment. This is a completely new insight.

Researchers from the NIOZ (Royal Dutch Institute for Sea Research) and JAMSTEC (Japanese Agency for Marine-Earth Science and Technology) found in their experiments that so-called foraminifera might even make their shells better in more acidic water. These single-celled foraminifera shellfish occur in huge numbers in the oceans. The results of the study are published in the leading scientific journal Nature Communications.

Since 1750 the acidity of the ocean has increased by 30%. According to the prevailing theory and related experiments with calcareous algae and shellfish, limestone (calcium carbonate) dissolves more easily in acidic water. The formation of lime by shellfish and corals is more difficult because less carbonate is available under acidic conditions. The carbonate-ion relates directly to dissolved carbon dioxide via two chemical equilibrium reactions.

Self-regulating biochemical magic trick

The classical theory is based on purely chemical processes by which the rate at which lime is created is determined entirely by the acidity of the water. NIOZ researcher and shared first author Lennart de Nooijer: "In our experiments the foraminifera were regulating the acidity at the micro level. In the places where shell formation occurs, the acidity was substantially lower than in the surrounding seawater. Foraminifera expel large amounts of hydrogen ions through their cell wall. This leads to acidification of their immediate micro-environment causing the equilibrium between carbon dioxide and carbonate to change in favour of carbon dioxide. The organism take up the increased concentration of carbon dioxide quickly through its cell wall. On the inner side of the cell wall, a low acidity prevails due to the massive excretion of protons. Under these conditions the ingested carbon dioxide is again converted to carbonate, which reacts with calcium to form lime. Such an active biochemical regulation mechanism has never been found before."

Can self-regulating single-celled organisms lead to a more rapid global warming?

The surface layer of the ocean is in equilibrium with the atmosphere. Therefore, more carbon dioxide in the air also leads to more dissolved carbon dioxide in the ocean's surface . "This finding may have important implications for the relationship between carbon dioxide levels in the air and the formation of calcareous structures by organisms," says co-author Professor Gert-Jan Reichart. "If the classic hypothesis holds and more carbon dioxide leads to less lime production, the oceans can continue to take up CO2 from the atmosphere. But what if the majority of the organisms can regulate the chemical form of their inorganic carbon by biochemical processes like our foraminifers did, and continue to form lime structures in a more acidic ocean? Over time, the concentration of dissolved carbon dioxide in the oceans may start to increase. Consequently, the ability of the oceans to take up a large part of the carbon dioxide in the air may start to decrease. This would mean that more carbon dioxide would remain in the air, leading to a more rapid warming of our planet."
-end-


NIOZ Royal Netherlands Institute for Sea Research

Related Shellfish Articles:

Rising sea levels destroyed evidence of shell middens at many prehistoric coastal sites
In a new study, researchers confirm a theory from the 1970s that coastal hunter-gatherers processed much of their shellfish at the beach before returning with their meat to camps on higher ground, leaving the heavy shells by the water.
Ancient Caribbean children helped with grocery shopping in AD 400
Researchers have long thought that snail and clam shells found at Caribbean archaeological sites were evidence of 'starvation food' eaten in times when other resources were lacking.
3,500 years of shellfish farming by indigenous peoples on the Northwest coast
The indigenous peoples of British Columbia have been harvesting shellfish from specially-constructed clam gardens for at least 3,500 years, according to a study released Feb.
Fried food linked to heightened risk of death among older US women
Regularly eating fried food is linked with a heightened risk of death from any cause and heart-related death, among postmenopausal women, finds a US study in The BMJ today.
One in 10 adults in US has food allergy, but nearly 1 in 5 think they do
Over 10 percent of adults in the US -- over 26 million -- are estimated to have food allergy.
Climate change poses significant threat to nutritional benefits of oysters
The nutritional qualities of shellfish could be significantly reduced by future ocean acidification and warming, a new study suggests.
Commercial shellfish landings decline likely linked to environmental factors
Researchers studying the sharp decline between 1980 and 2010 in documented landings of the four most commercially-important bivalve mollusks -- eastern oysters, northern quahogs, softshell clams and northern bay scallops -- have identified the causes.
Blue crab baby sizes and shapes influence their survival
Like people, blue crabs aren't all the same sizes and shapes.
Sea snail shells dissolve in increasingly acidified oceans, study shows
Shelled marine creatures living in increasingly acidified oceans face a fight for survival as the impacts of climate change spread, a new study suggests.
Small-scale fisheries threatened: Shared management, communication key to success
New research shows that co-management approaches -- based on shared responsibility for resource management among individuals and institutions -- can build resilience to socio-environmental change by strengthening use of science in decision making and promoting adaptive capacities, such as learning and leadership.
More Shellfish News and Shellfish Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.