Arctic Ocean acidification could reach levels far greater than predicted if emissions stay high

Arctic Ocean acidification could reach levels far greater than predicted if emissions stay high

SOURCE: The Narwhal DATE: June 26, 2020 SNIP: The Arctic Ocean could absorb 20 per cent more carbon than previously predicted before the end of the century, according to a recent study. It’s a jump that could result in even more acidification, jeopardizing marine wildlife. About 7.5 billion tonnes of carbon was projected to be absorbed by the Arctic Ocean in previous estimates, said Jens Terhaar, the lead author of the research paper, released this month in the journal Nature. The new study — a joint undertaking between the University of Bern in Switzerland and École normale supérieure in Paris — found that this number is actually 1.5 billion tonnes higher (under what’s commonly known as the ‘business as usual’ or RCP8.5 high emissions scenario), reaching 9 billion tonnes of carbon absorbed by 2100. While the Arctic Ocean represents 1 per cent of global seawater, it’s by far the most vulnerable to a changing climate, Terhaar said. “That’s mainly just because it’s very cold and colder water holds more carbon.” The Arctic, in general, will bear the most severe effects of climate change, the study...
Arctic Ocean acidification worse than previously expected

Arctic Ocean acidification worse than previously expected

SOURCE: Bern University DATE: June 17, 2020 SNIP: The Arctic Ocean will take up more CO2 over the 21st century than predicted by most climate models. This additional CO2 causes a distinctly stronger ocean acidification. These results were published in a study by climate scientists from the University of Bern and École normale supérieure in Paris. Ocean acidification threatens the life of calcifying organisms – such as mussels and “sea butterflies” – and can have serious consequences for the entire food chain. The ocean takes up large amounts of man-made CO2 from the atmosphere. This additional CO2 causes ocean acidification, a process that can already be observed today. Ocean acidification particularly impacts organisms that form calcium carbonate skeletons and shells, such as molluscs, sea urchins, starfish and corals. The Arctic Ocean is where acidification is expected to be greatest. A study that was recently published in the scientific journal Nature by Jens Terhaar from Bern and Lester Kwiatkowski and Laurent Bopp from the École normale supérieure in Paris shows, that ocean acidification in the Arctic Ocean is likely to be even worse than previously thought. The results show that the smallest of the seven seas will take up 20% more CO2 over the 21st century than previously expected, under the assumption that the atmospheric CO2 concentrations continue to increase. “This leads to substantially enhanced ocean acidification, particularly between 200 and 1000 meters”, explains Jens Terhaar, member of the group for ocean modeling at the Oeschger-Centre for Climate Change Research at the University of Bern. This depth range is an important refuge area for many marine organisms. Ocean acidification negatively...
North Atlantic’s capacity to absorb CO2 overestimated, study suggests

North Atlantic’s capacity to absorb CO2 overestimated, study suggests

SOURCE: The Guardian DATE: April 3, 2020 SNIP: The North Atlantic may be a weaker climate ally than previously believed, according to a study that suggests the ocean’s capacity to absorb carbon dioxide has been overestimated. A first-ever winter and spring sampling of plankton in the western North Atlantic showed cell sizes were considerably smaller than scientists assumed, which means the carbon they absorb does not sink as deep or as fast, nor does it stay in the depths for as long. This discovery is likely to force a negative revision of global climate calculations, say the authors of the Nasa-backed study, though it is unclear by how much. “We have found a misconception. It will definitely impact the model of carbon flows,” said Oregon State University microbiologist Steve Giovannoni. “It will require more than just a small tweak.” Researchers say the spring phytoplankton bloom in the North Atlantic is probably the largest annual biological carbon sequestration mechanism on the planet. Like a vast forest of tiny plants in the sunlight upper part of the ocean, they draw down carbon dioxide through photosynthesis. The bigger the plankton, the higher the chance they will sink into the deep mesopelagic zone of the ocean, where carbon can be trapped for more than 1,000 years. Until now, climate models have assumed that diatoms – one of the biggest types of plankton – were dominant. But the study, published in the International Society for Microbial Ecology Journal, reveals they are a very minor share of biomass when compared with much smaller cyanobacteria, picophytoeukaryotes and nanophytoeukaryotes. This was expected in winter, but the research...
Gulf Coast Coral Likely To Face Widespread Destruction By The End Of The Century

Gulf Coast Coral Likely To Face Widespread Destruction By The End Of The Century

SOURCE: Kera News DATE: December 26, 2019 SNIP: Without a significant reduction in greenhouse gas emissions, coral reefs throughout the Gulf of Mexico are likely to face widespread bleaching and collapse by the end of the century, according to a new report from several research universities. Researchers from Rice University, the University of Texas at Austin and Louisiana State University used climate models to project future changes in the Gulf’s waters, from Texas to Florida. Specifically, they looked at factors that stress coral reefs, such as temperature rise and acidification. “All of the trends are negative in that we find that the oceans are warming; the ocean is becoming more acidic. Everything that is conducive to coral health is being degraded rapidly,” said Sylvia Dee, an assistant professor of Earth, environmental and planetary sciences at Rice. “What we can say with certainty is that by the end of the 21st century it is highly likely, and almost certain, that many of the coral reef communities in the Gulf of Mexico will be undergoing heating conditions and acidification conditions that are likely to destroy them.” The Gulf Coast is home to numerous coral reef systems, many of which are inside protected areas such as Florida’s John Pennekamp state park and the Flower Banks National Marine Sanctuary off the coast of Galveston. The reefs support fisheries, help protect coastlines and contribute to tourism, Dee said. The researchers also looked at other factors contributing to poor coral health, such as runoff pollution, coral mining and over-fishing. “Those are problems that could be eradicated now, those things could be stopped immediately,” she...
The world’s oceans are acidifying — but it’s happening twice as fast off California

The world’s oceans are acidifying — but it’s happening twice as fast off California

SOURCE: NBC News DATE: December 16, 2019 SNIP: The waters off California are acidifying twice as rapidly as elsewhere on Earth, according to a study published Monday, which suggests that climate change is likely hastening and worsening chemical changes in the ocean that could threaten seafood and fisheries. Oceans play an important role in the planet’s delicate carbon cycle, acting as a crucial reservoir that absorbs and stores carbon dioxide from the atmosphere. But the new research finds that although oceans can withstand some natural variations in climate, global warming may be adding to the stress on those ecosystems and overwhelming their ability to cope. “The system is adapted to experience and be able to thrive in a variable environment, but when you add extra stress, these changes become more extreme,” said Emily Osborne, a researcher at the National Oceanic and Atmospheric Administration, or NOAA, the lead author of the study, which was published in the journal Nature Geoscience. Osborne and her colleagues analyzed almost 2,000 fossil shells of a tiny organism known as planktonic foraminifera to create a 100-year history of ocean acidification along the California coast. The organisms, which live for only about a month, use calcium carbonate to build their shells, which means they leave behind clues about their environment. As oceans become more acidic, sea creatures struggle to build up hardier shells, Osborne said, which allowed her and her colleagues to study the thickness of foraminifera shells and trace levels of ocean acidity back through time. They found that the organisms’ shells were thinning as oceans became more acidic. “We saw a clear, long-term declining...