Climate change: Marine heatwaves kill coral instantly

Climate change: Marine heatwaves kill coral instantly

SOURCE: BBC DATE: August 9, 2019 SNIP: Increasingly frequent marine heatwaves can lead to the almost instant death of corals, scientists working on the Great Barrier Reef have found. These episodes of unusually high water temperatures are – like heatwaves on land – associated with climate change. Scientists studying coral after a heat event discovered that extreme temperature rises decayed reefs much more rapidly than previously thought. The study revealed that corals became up to 15% weaker after an extreme heat event, causing some fragments to actually break off from the reef. Dr Tracy Ainsworth, from the University of New South Wales in Australia, worked on the study. She told BBC News that her whole research team, made up of scientists who have worked on corals for more than a decade, was shocked to find them to be “really brittle”. More typically, temperature rises cause something called coral bleaching – when the coral expels vital algae that lives in its tissues. In those events, the coral itself remains intact. “But what we’re seeing here is that – when the coral tissue dies – it falls and breaks away from the skeleton,” Dr Ainsworth explained. Commenting on the paper, Dr Laura Richardson, from the School of Ocean Sciences at Bangor University, UK, said that the really significant discovery was “the rapidity with which the reef skeleton breaks down when you have these severe heatwaves”. Dr Richardson added that the team had documented, for the first time, that severe heatwaves were causing “almost instant mortality of corals”. Dr Ainsworth said the researchers referred to the resulting, heat-damaged skeletons as “ghost corals,...
Surprise! Unexpected ocean heat waves are becoming the norm

Surprise! Unexpected ocean heat waves are becoming the norm

SOURCE: The Daily Climate and PNAS DATE: August 6, 2019 SNIP: Ocean heat waves, which can push out fish, plankton and other aquatic life, are happening far more frequently than previously thought, according to a study published today in the Proceedings of the National Academy of Sciences. “Based on historical and lived experience, people expect certain conditions to prevail in the ecosystems they depend upon. Climate change is now introducing strong trends that push conditions beyond historic levels,” the authors wrote. Led by the Gulf of Maine Research Institute, researchers looked at 65 large marine ecosystems around the world over the past 164 years to determine how frequently “surprising” ocean temperatures occur, with surprising defined as an event expected to occur about two times in 100 years, lead author and chief scientific officer at the Gulf of Maine Research Institute Andrew Pershing told EHN via email. Pershing and colleagues reported that over the past seven years, the planet averaged 12 ecosystems each year experiencing the kind of unusually warm temperatures that someone in the given region would expect to see only a couple times in a century. In 2016 alone there were 23 such events. “Across the 65 ecosystems we examined, we expected about six or seven of them would experience these ‘surprises’ each year,” Pershing said in a statement. The results are in line with what scientists continue to warn: oceans are the Earth’s largest heat collector. According to the National Oceanic and Atmospheric Administration, more than 90 percent of Earth’s warming over the past 50 years has happened in the...
Heatwave cooks mussels in their shells on California shore

Heatwave cooks mussels in their shells on California shore

SOURCE: The Guardian DATE: June 29, 2019 SNIP: In all her years working at Bodega Bay, the marine reserve research coordinator Jackie Sones had never seen anything like it: scores of dead mussels on the rocks, their shells gaping and scorched, their meats thoroughly cooked. A record-breaking June heatwave apparently caused the largest die-off of mussels in at least 15 years at Bodega Head, a small headland on the northern California bay. And Sones received reports from other researchers of similar mass mussel deaths at various beaches across roughly 140 miles (225km) of coastline. While the people who flocked to the Pacific to enjoy a rare 80F (27C) beach day soaked up the sun, so did the mussel beds—where the rock-bound mollusks could have been experiencing temperatures above 100F at low tide, literally roasting in their...
Climate Change Threat to Dolphins’ Survival

Climate Change Threat to Dolphins’ Survival

SOURCE: University of Zurich DATE: April 1, 2019 SNIP: An unprecedented marine heatwave had long-lasting negative impacts on both survival and birth rates on the iconic dolphin population in Shark Bay, Western Australia. Researchers at UZH have now documented that climate change may have more far-reaching consequences for the conservation of marine mammals than previously thought. Shark Bay in Western Australia in early 2011: A heatwave causes the water temperatures to rise to more than four degrees above the annual average. The extended period caused a substantial loss of seagrass, which drives the Shark Bay ecosystem, in this coastal area, a UNESCO world heritage site. Researchers from UZH have now investigated how this environmental damage has affected survival and reproduction of dolphins. They used long-term data on hundreds of animals collected over a ten-year period from 2007 to 2017. Their analyses revealed that the dolphins’ survival rate had fallen by 12 percent following the heatwave of 2011. Moreover, female dolphins were giving birth to fewer calves – a phenomenon that lasted at least until 2017. “The extent of the negative influence of the heatwave surprised us,” says Sonja Wild, former PhD candidate at the University of Leeds and first author of the study. “It is particularly unusual that the reproductive success of females appears to have not returned to normal levels, even after six...
Ocean Warming Is Accelerating Faster Than Thought, New Research Finds

Ocean Warming Is Accelerating Faster Than Thought, New Research Finds

SOURCE: NY Times DATE: January 10, 2019 SNIP: Scientists say the world’s oceans are warming far more quickly than previously thought, a finding with dire implications for climate change because almost all the excess heat absorbed by the planet ends up stored in their waters. A new analysis, published Thursday in the journal Science, found that the oceans are heating up 40 percent faster on average than a United Nations panel estimated five years ago. The researchers also concluded that ocean temperatures have broken records for several straight years. “2018 is going to be the warmest year on record for the Earth’s oceans,” said Zeke Hausfather, an energy systems analyst at the independent climate research group Berkeley Earth and an author of the study. “As 2017 was the warmest year, and 2016 was the warmest year.” As the planet has warmed, the oceans have provided a critical buffer. They have slowed the effects of climate change by absorbing 93 percent of the heat trapped by the greenhouse gases humans pump into the atmosphere. Because they play such a critical role in global warming, oceans are one of the most important areas of research for climate scientists. Average ocean temperatures are also a consistent way to track the effects of greenhouse gas emissions because they are not influenced much by short-term weather patterns. As the oceans heat up, sea levels rise because warmer water takes up more space than colder water. In fact, most of the sea level rise observed to date is because of this warming effect, not melting ice...