Ocean acidification

While previous studies indicate some life stages of Antarctic krill may be vulnerable to ocean acidification, the research published in the Nature journal Communications Biology found that adult krill were largely unaffected by ocean acidification levels predicted within the next 100-300 years.

The study’s lead author, IMAS PhD student Jess Ericson, said the long-term laboratory study was the first of its kind.

“Our study found that adult krill are able to survive, grow and mature when exposed for up to one year to ocean acidification levels that can be expected this century,” Ms Ericson said.

Continue reading ‘Business as usual for Antarctic krill despite ocean acidification’

Adult Antarctic krill have a secret weapon for survival in a high carbon dioxide world, according to new research published today in Communications Biology.

Australian Antarctic Program scientists have found adult krill have special ion pumps in their gills that allow them to maintain the pH of their body fluid (‘haemolymph’) under a wide range of carbon dioxide (CO₂) concentrations.

Continue reading ‘Antarctic krills’ secret weapon against ocean acidification (text and video)’

The ocean floor as we know it is dissolving rapidly as a result of human activity.

Normally the deep sea bottom is a chalky white. It’s composed, to a large extent, of the mineral calcite (CaCO3) formed from the skeletons and shells of many planktonic organisms and corals. The seafloor plays a crucial role in controlling the degree of ocean acidification. The dissolution of calcite neutralizes the acidity of the CO2, and in the process prevents seawater from becoming too acidic. But these days, at least in certain hotspots such as the Northern Atlantic and the southern Oceans, the ocean’s chalky bed is becoming more of a murky brown. As a result of human activities the level of CO2 in the water is so high, and the water is so acidic, that the calcite is simply being dissolved.

The McGill-led research team who published their results this week in a study in PNAS believe that what they are seeing today is only a foretaste of the way that the ocean floor will most likely be affected in future.

Continue reading ‘Alterations to seabed raise fears for future’

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).

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.

Continue reading ‘Sea snail shells dissolve in increasingly acidified oceans, study shows’

Credit: Photos courtesy of Liang Xue/ University of Delaware

Antarctica has a current that circles the landmass as part of the Southern Ocean. This current is called the Antarctic Circumpolar Current. When the westerly winds strengthen during the Southern Hemisphere’s summer, waters south of the current acidify faster than can be accounted for in carbon dioxide from the atmosphere alone. The opposite pattern was observed north of the current.

Why does this happen and why does it matter?

University of Delaware Professor Wei-Jun Cai co-wrote a paper that appeared in Nature Communications and addresses those questions.

Researchers involved in the study say these effects are due to a combination of processes driven by these westerly winds — a theory that was borne out by two decades’ worth of observational data from south of Tasmania.

Understanding the factors that control ocean acidification is important for predicting the impact that the changing chemistry of the ocean will have on marine organisms and ecosystems in the future. The Southern Ocean, also known as the Antarctic Ocean, is a critical place to study these mechanisms because of its vast capacity to store carbon dioxide from the atmosphere, a crucial component of climate change.

Continue reading ‘Oceans are changing: New understanding of acidification in Southern Ocean’

The first broad-scale assessment of ocean-based solutions to reduce climate change and its impacts shows their high potential and calls for immediate development and scale-up of the most-promising measures

Ambitious and rapid action is needed to reduce climate change and its impacts — and the first broad-scale assessment of ocean-based solutions shows the focus should be on the oceans. The study looks at the feasibility of 13 ocean-based measures to reduce atmospheric carbon dioxide (CO2), counteract ocean warming and/or reduce impacts like ocean acidification and sea-level rise. It identifies ocean-based renewable energy as the most promising, and several local marine conservation and restoration options as ‘no-regret measures’, that should be scaled-up and implemented immediately, but concludes all other measures are still too uncertain to recommend without further research. Published in Frontiers in Marine Science as part of the article collection ‘Successes at the Interface of Ocean, Climate and Humans’, the study highlights the trade-offs and governance issues associated with all solutions and emphasizes that the greatest benefit will come from combining global and local solutions through policy cooperation.

Continue reading ‘Climate change efforts should focus on ocean-based solutions’