Ocean acidification

U.S. and Australian researchers have found a potential tool for identifying “super corals” that can tolerate a limited amount of climate change.

“We may be able to use algae team characteristics to identify coral colonies to focus on for conservation or restoration,'” said veteran reef researcher Adrienne Correa, a Rice University marine biologist and co-author of a newly published study in the journal Global Change Biology. “It’s not sufficient — if we don’t limit carbon dioxide emissions, it’s not going to be enough to save coral reefs — but it’s exciting.”

In the study, marine biologists from the Australian Institute of Marine Science (AIMS) gathered corals from the Great Barrier Reef and used separately controlled tanks to compare how well they responded to rising ocean temperatures, increased acidity and exposure to bacterial pests.

Continue reading ‘A coral’s symbiotic community may predict how well it resists climate stress’

A diver collecting samples near a volcanic vent. Credit: University of Otago

University of Otago scientists are leading research into the possibility that the shallow submarine vents off New Zealand’s volcanic Whakaari/White Island could provide a natural laboratory to study the impacts of future climate change on our oceans.

Submarine vents have natural gradients in climate variables like pH and temperature making them useful examples of future seawater conditions. Over the past few decades scientists have investigated submarine vents, particularly in deep waters, tropical and subtropical waters and in warm temperate seas to evaluate the long-term effects of climate change on our oceans.

“Vent studies in cold temperate waters in the southern hemisphere are scarce and it is important to know how climate change, and ocean acidification in particular, will affect our temperate species and ecosystems,” says Dr. Rebecca Zitoun of the University of Otago’s Chemistry Department.

Continue reading ‘Testing seawater of the future? a study at Whakaari/White Island’

Commercially important oysters are vulnerable to ocean acidification. Creative Commons

When it comes to carbon emissions, people tend to focus more on what happens in the atmosphere and on land. But about a quarter of carbon emissions dissolve into oceans, lowering the water’s pH and causing ocean acidification.

That could affect what kind of seafood is on the menu in coming years. Species such as oysters and clams appear to be vulnerable to the change while others, including lobsters and crabs, are more resilient.

Robert Eagle, a UCLA expert on climate change and oceans, has explored the complex ways acidification affects marine life. Perhaps the biggest concern is that acidification interferes with the ability of organisms such as corals to form shells and skeletons — but it doesn’t affect all shell-forming organisms in the same way. Some are unaffected or actually grow faster in more acidic waters, previous research showed. But why?

Continue reading ‘Oysters as catch of the day? Perhaps not, if ocean acidity keeps rising’

A sample of the peppery furrow shell (Scrobicularia plana) as used in the research. (Carl Van Colen, Ghent University)

Projected ocean warming and acidification not only impacts the behaviour of individual species but also the wider marine ecosystems which are influenced by them, a new study shows.

Research published in Nature Climate Change shows that in warmer seawater with lower pH, a common clam – the peppery furrow shell (Scrobicularia plana) – makes considerable changes to its feeding habits.

Instead of relying predominantly on food from within the water column, it changed its behaviour to use its tube-like feeding siphon to scrape more of its food from the seafloor.

Continue reading ‘Warmer and acidified oceans can lead to ‘hidden’ changes in species behavior’

A seaweed species crucial to the survival of coral reefs may be able to gain resistance to ocean changes caused by climate change, new Te Herenga Waka—Victoria University of Wellington research recently published in Nature Climate Change shows.

The research, led by Dr Christopher Cornwall from the University’s School of Biological Sciences, showed that coralline algae can build tolerance to ocean acidification, one of the major side-effects of climate change over multiple generations.

“Coralline algae go through a natural process of calcification, where they build a calcium carbonate skeleton,” Dr Cornwall says. “Skeletons like this provide structure, allow them to grow, and protect these organisms. Our research has shown that growth of these skeletons is susceptible to climate change, at least initially.”

Continue reading ‘Crucial reef species may survive ocean changes under climate change’

New high-resolution maps show limited ocean capacity to absorb excess carbon dioxide

An international team led by researchers at the University of Maryland and the National Oceanic and Atmospheric Administration has created the most high-resolution maps to date showing changes in the pH of seawater since the Industrial Revolution began. Their study, published in the December 9, 2019 issue of the journal Nature Scientific Reports, suggests that the ocean’s capacity to continue absorbing carbon dioxide (CO2) from the atmosphere is diminishing.

Continue reading ‘Are we losing a key climate change buffer? (video)’

Denticles — the modified scales — of a puffadder shyshark seen through an optical microscope (left) and a scanning electron microscope (right) of CO2 exposed sharks denticles. Credit: Lutz Auerswald (left) / Jacqueline Dziergwa (right)

While regular fish have flat scales, shark ‘scales’ look more like teeth. But their denticles also cover their body and in particular influence their ability to swim. The denticles are made up of a compounds containing calcium.

The increasing amount of carbon dioxide (CO2) in the atmosphere due to climate change has also led to a higher concentration of CO2 in the oceans. The CO2 dissolves in the seawater to create carbonic acid that acidifies the oceans.

This higher acidity has already been found to damage the calcium carbonate in corals and other animals with calcium-based structures. The research team from three South African research institutions, from the University of Duisburg-Essen and HHU has now examined whether the more acidic seawater is also affecting sharks.

Continue reading ‘Ocean acidification is damaging shark scales’