Biologists create historic record of climate change impacts
The shells of California mussels have thinned dramatically in the modern era, probably as a result of ocean acidification, a direct result of increased carbon dioxide in the atmosphere resulting from fossil fuel combustion, say University of Chicago biologists who compared mussel specimens collected in the 1970s with present-day samples.
In the 70s, the shells were on average 32 percent thicker than modern specimens. Going back even farther, the researchers said shells collected by Native Americans 1,000 to 1,300 years ago were also 27 percent thicker than modern shells.
“Archival material provided by past researchers, the Makah Tribal Nation, and the Olympic National Park allowed us to document this intriguing and concerning pattern in shell thickness,” said Cathy Pfister, PhD, professor of ecology and evolution at the University of Chicago and lead author. The study was published June 15, 2016, in the Proceedings of the Royal Society B. Continue reading “Climate: California mussel shells thinning as oceans acidify”→
Study shows how changing ocean chemistry slows life cycle
Ocean acidification could take a bite out of the economically important Dungeness crab fishery along the Pacific Northwest coast. As the oceans absorb more CO2 from the atmosphere, the increasingly corrosive water is likely slow development and reduce survival of the crab’s larval stages, according to new research by the NOAA Fisheries Northwest Fisheries Science Center in Seattle.
Ocean acidification is one of the most serious effects of increasing CO2 emissions from fossil fuel combustion. Based on what we know about emissions trends, the average pH of surface waters off the Pacific Northwest Coast is expected to drop to about 7.8, and even more when periodic upwelling carries deep water to the surface. Acidification has already been found to slow coral growth, impair shark feeding, and speed the spread of invasive species, among other impacts.
The study, recently published in the journal Marine Biology, shows that the crab larvae hatched at the same rate regardless of pH, but those that hatched at lower levels showed signs of slowed development. The researchers suggested that the lower pH may reduce the metabolic rate of embryos. That could extend their vulnerable larval period, or could jeopardize the timing of their development in relation to key food sources, the scientists said. Continue reading “Ocean acidification puts Dungeness crab fishery at risk”→
Scientists are urging resource managers along the West Coast of North America to start using adaptive strategies in the face of ocean acidification and hypoxia caused by global carbon dioxide emissions.
The 20-member panel of ocean experts said the West Coast is a hotspot for climate change impacts because of upwelling cold water that that transports nutrient-rich, low-oxygen and high carbon dioxide water from deep in the water column to the surface near the coast.
‘If we don’t take action … coral reefs will not survive into the next century’
The most dangerous effects of global warming may still be decades away, but ocean scientists say that the buildup of carbon dioxide is already slowing down the growth of coral reefs. By simulating ocean acidification on a section of the Great Barrier Reef, the researchers showed that excess C02 in the atmosphere is affecting coral reefs.
“Our work provides the first strong evidence from experiments on a natural ecosystem that ocean acidification is already causing reefs to grow more slowly than they did 100 years ago,” said study lead author Rebecca Albright, a marine biologist in Carnegie’s Department of Global Ecology in Stanford, Calif. “Ocean acidification is already taking its toll on coral reef communities. This is no longer a fear for the future; it is the reality of today.” Continue reading “Study says ocean acidification has already slowed coral growth”→