Category: ocean acidification

Sea snails showing signs of global warming wear and tear

Study helps quantify ocean acidification impacts

snails
Scientists estimate that pteropod shell dissolution has increased 20 to 25 percent on average in waters along the U.S. West Coast due to CO2 emitted by humans.

Staff Report

By mapping CO2 emissions and comparing that information with data on CO levels in the ocean, scientists say they can now show to what degree the build-up of heat-trapping pollution contributes to the dissolving of shells of microscopic marine sea snails called pteropods.

Other studies from the Southern Hemisphere have reached similar conclusions. Pteropods are an important food for commercially valuable fish species like salmon, sablefish and rock sole.

“This is the first time we’ve been able to tease out the percentage of human-caused carbon dioxide from natural carbon dioxide along a large portion of the West Coast and link it directly to pteropod shell dissolution,” said Richard Feely, a NOAA senior scientist who led the research. Continue reading “Sea snails showing signs of global warming wear and tear”

The Paris climate agreement is now in force

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Can the world live up to the ambitions of the Paris climate agreement? @bberwyn photo.

Now the hard work begins …

Staff Report

As the Paris climate agreement goes into effect, it’s important to remember that, so far, there’s been a lot more talk than action by the global community. Plans are one thing, action is another, and unless there are significant cuts in greenhouse gas emissions in the next few years, there’s almost no chance to limit global warming to less than 2 degrees Celsius.

Here are some sobering facts to show why immediate action is needed, starting with the latest annual greenhouse gas bulletin from the World Meteorological Organization.

Carbon dioxide, methane and nitrous oxide all reached new record high concentrations in the atmosphere in 2015. According to the analysis, CO2 levels are not 144 percent higher than in pre-industrial times; methane is 256 percent higher, and nitrous oxide is 121 percent higher. It’s likely that CO2 concentrations, as measured at Mauna Loa, will stay above 400 parts per million for all of 2016. The increase of methane from 2014 to 2015 was larger than that observed from 2013 to 2014 and that averaged over the last decade. Continue reading “The Paris climate agreement is now in force”

New surveys confirm Great Barrier Reef damage

Heat-driven coral bleaching continues to take a toll

Staff Report

A new survey of the Great Barrier Reef shows that an ocean heat wave that peaked last March killed up to 95 percent of corals in some parts of the northern reef.  And in the aftermath of the worst coral-bleaching event on record, predatory snails are now taking on toll on the remaining corals.

According to the ARC Centre of Excellence for Coral Reef Studies, researchers recently returned to 83 reefs they surveyed at the height of the bleaching event.

“Millions of corals in the north of the Great Barrier Reef died quickly from heat stress in March and since then, many more have died more slowly,” said Dr. Greg Torda whose team recently returned from re-surveying reefs near Lizard Island. Continue reading “New surveys confirm Great Barrier Reef damage”

How long can the oceans soak up CO2?

What’s the tipping point?

Researchers examine ocean acidification rates

Staff Report

For now, the world’s oceans are sucking up so much carbon dioxide that it’s helping to slow the rate of global warming. But that’s expected to change in the future, researchers warned after taking a detailed look at the rate of ocean acidification in the northeast Pacific Ocean. Continue reading “How long can the oceans soak up CO2?”

Ocean acidification seen as huge threat to Atlantic cod

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Climate change to put a big hit on cod stocks.

Fish larvae seen as highly sensitive to CO2

Staff Report

New lab experiments suggest that increasing ocean acidification could take a big bite out of the economically important cod fishery in the North Atlantic. The research suggests that the buildup of CO2 in the ocean could double the mortality of newly-hatched cod larvae.

Members of the German research network BIOACID quantified the impacts, showing that recruitment could decrease to levels of one quarter to one twelfth of the recruitment of the last decades. Cod have already been under intense fishing pressure for decades, and the new study, published in the online journal PLOS ONE, identifies climate change as an emerging new threat. Continue reading “Ocean acidification seen as huge threat to Atlantic cod”

Climate: California mussel shells thinning as oceans acidify

A new study shows California mussel shells are getting thinner because of ocean acidification. @bberwyn photo.
A new study shows California mussel shells are getting thinner because of ocean acidification. @bberwyn photo.

Biologists create historic record of climate change impacts

Staff Report

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”

Ocean acidification puts Dungeness crab fishery at risk

Study shows how changing ocean chemistry slows life cycle

Dungeness crab
Ocean acidification will slow the reproductive cycle of Dungeness crabs, according to a new study. Photo courtesy NOAA.

Staff Report

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”