Oceans: West Coast oysters facing multiple threats

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Oysters face an uncertain future.

Climate change makes young oysters more vulnerable to invasive snails

By Summit Voice

FRISCO — West Coast oysters could be facing a double whammy of global warming and invasive snails, according researchers with University of California, Davis’ Bodega Marine Laboratory.

Lab tests suggests that, as oceans become more acidic from the buildup of carbon dioxide in the atmosphere, oysters will be smaller, and invasive snails will take a bigger toll.

Specifically, invasive snails ate 20 percent more juvenile oysters when both species were raised under ocean conditions forecast for the end of this century The results highlight the dangers of multiple stressors on ecosystems, said Eric Sanford, professor of evolution and ecology at UC Davis and first author on the study. Continue reading

Study tracks natural variability of ocean acidity

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Ocean acidification will have impacts on most life in the coastal zone. bberwyn photo.

‘For vulnerable coastal marine ecosystems, this may be adding insult to injury …’

By Summit Voice

FRISCO — In addition to the long-term threat of ocean acidification resulting from increased atmospheric greenhouse gases, marine organisms also must deal with short-term spikes of increased acidity.

Those acute episodes are caused by a variety of natural factors, including temperature and algal activity, according to a new study led by researchers with Duke University, who took a close look at natural cycles of acidity in a North Carolina estuary.

“The natural short-term variability in acidity we observed over the course of one year exceeds 100-year global predictions for the ocean as a whole,” said  Zackary I. Johnson, a molecular biologists at Duke’s Nicholas School of the Environment. Continue reading

Are fish getting ‘anxious’ about global warming?

New study shows behavioral impacts of ocean acidification

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Is ocean acidification making Pacific rockfish more anxious? Photo courtesy NOAA.

By Summit Voice

FRISCO — If you think you’re worried about climate change, just imagine how some ocean critters must be feeling as the seas become ever-warmer and more acidic. Numerous studies already show the physiological impacts of ocean acidification, and new research suggests there may also be behavioral ramifications.

The study, combining marine physiology, neuroscience, pharmacology, and behavioral psychology, revealed a surprising outcome from increases of carbon dioxide uptake in the oceans: Anxious fish.

To track the impacts, scientists with Scripps Institution of Oceanography at UC San Diego and MacEwan University in Edmonton, Canada used a camera-based tracking software system to compare the behavior of two groups of rockfish. The control group was kept in normal seawater, while the test group was exposed to water with elevated acidity levels matching those projected for the end of the century. Continue reading

Early warning system needed for ‘abrupt’ climate change impacts

Researchers eye global warming thresholds

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By Summit Voice

FRISCO — Climate researchers say more should be done to develop an early warning system for ecological tipping points that could be reached as the ocean, land and atmosphere gradually warm.

Some large and rapid changes could happen in a relatively short time as critical thresholds are breached, the scientists said in a new report from the National Research Council.

“Research has helped us begin to distinguish more imminent threats from those that are less likely to happen this century,” said James W.C. White, professor of geological sciences at the University of Colorado, Boulder, and chair of the committee that wrote the report. “Evaluating climate changes and impacts in terms of their potential magnitude and the likelihood they will occur will help policymakers and communities make informed decisions about how to prepare for or adapt to them.” Continue reading

Climate: Ocean acidification will have huge costs

Coral reef erosion is likely to outpace reef building this century

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The acidity of the world’s oceans could increase by 170 percent by the end of the century, as greenhouse gas emissions continue nearly unabated. bberwyn photo.

By Summit Voice

FRISCO — The legacy of historical fossil fuel emissions on ocean acidification will be felt for centuries, an international team of scientists concluded in a new report, warning that the world needs to prepare for major losses of ecosystem services.

If carbon dioxide emissions continue on their current trajectory, the acidity of the world’s oceans may increase by around 170 percent by the end of the century, the report found. People who rely on the ocean’s ecosystem services — often in developing countries — are especially vulnerable.

“What we can now say with high levels of confidence about ocean acidification sends a clear message,” said Ulf Riebesell, of the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany. “Globally we have to be prepared for significant economic and ecosystem service losses. But we also know that reducing the rate of carbon dioxide emissions will slow acidification. That has to be the major message for the COP19 meeting.” Continue reading

No corner of the ocean safe from global warming

Widespread impacts expected by the end of the century

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A rapidly melting glacier on Deception Island, near Antarctica, pours fresh water into the ocean. bberwyn photo.

By Summit Voice

FRISCO — A warming climate will fundamentally change nearly all the world’s oceans by the end of the century, researchers warned this week. In addition to oft-discussed impacts of warmer water temperatures and ocean acidification, climate change will also deplete dissolved oxygen and lower the overall productivity of marine ecosystems.

“When you look at the world ocean, there are few places that will be free of changes; most will suffer the simultaneous effects of warming, acidification, and reductions in oxygen and productivity,” said lead author Camilo Mora, assistant professor at the Department of Geography in the College of Social Sciences at the University of Hawai’i at Manoa.

The study described the full chain of events by which ocean biogeochemical changes triggered by manmade greenhouse gas emissions may cascade through marine habitats and organisms, penetrating to the deep ocean and eventually influencing humans. Continue reading

Study: New climate extremes just around the corner

“We are pushing the ecosystems … out of the environment in which they evolved ‘

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Tropical regions will be the first to move outside the bounds of historic norms.

By Summit Voice

FRISCO — Starting with the tropics, many locations on Earth will start to see new climate normals within the next few decades — Kingston, Jamaica could reach that point within the next decade, and other well-known cities, including Singapore, Mexico City and Phoenix will see off-the-chart temperatures by mid-century, according to climate scientists and geographers with the University of Hawaii, Manoa.

Their study, published Oct. 10 in Nature, creates an index of the year when the mean climate of any given location on Earth will shift continuously outside the most extreme records experienced in the past 150 years.

The index used the minimum and maximum temperatures from 1860-2005 to define the bounds of historical climate variability at any given location. The scientists then took projections for the next 100 years to identify the year in which the future temperature at any given location on Earth will shift completely outside the limits of historical precedents, defining that year as the year of climate departure.

“The results shocked us. Regardless of the scenario, changes will be coming soon,” said lead author Camilo Mora. “Within my generation, whatever climate we were used to will be a thing of the past.” Continue reading

New IPCC report highlights increasing certainty on global warming causes and consequences

Future looks grim without drastic greenhouse gas cuts

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Warmer and wetter times ahead.

By Bob Berwyn

FRISCO — The news is out and it’s not good. In fact, the latest update of the Intergovernmental Panel on Climate Change is full of dire warning signs that the continued buildup of heat-trapping greenhouse gases, if left unchecked, will lead to a climate catastrophe with dire consequences for humanity and the rest of the planet’s species.

The full assessment is being released piecemeal, with this week’s Summary for Policy Makers drawing global attention, as every word and phrase is scrutinized and parsed for meaning. And it’s actually not that hard to figure out what it all means — you don’t even have to be a scientist. Continue reading

Study seeks early warning of ecological tipping points

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Penguins could be a species prone to an ecological tipping point. bberwyn photo.

Ecosystem collapses could also have serious economic and social consequences

By Summit Voice

FRISCO — One of the biggest concerns raised by the rapid rise in global temperatures the past few decades is that some ecosystems may reach an environmental tipping point, from beyond which there is no recovery.

It’s hard to predict where those tipping points are and when they might be reached, but a team of scientists with NOAA Fisheries, University of California at Santa Barbara, Stanford University, and Environmental Defense Fund wants to know if it’s at least possible to detect early warning signs in the world’s oceans.

The Ocean Tipping Points Project includes scientists and other experts from NOAA Fisheries, University of California at Santa Barbara, Stanford University, and Environmental Defense Fund. The Project is just getting off the ground with a recent $3.1 million grant from the Gordon and Betty Moore Foundation. Continue reading

Global warming: Study shows far-reaching impacts of ocean acidification

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British Antarctic Survey scientists documented how increasingly corrosive water affects the shells of pteropods. Photo courtesy BAS.

German researchers see “ominous change” in increasing CO2 levels

By Summit Voice

FRISCO — There’s no question that the rapid acidification of the oceans will disrupt ecosystems and perhaps even wipe out some of the most sensitive species, including some shellfish.

British Antarctic Survey researchers last year showed how corrosive waters in the southern Ocean is destroying sea snail shells. Other studies suggest mussel beds in the Pacific Northwest may also be feeling the impacts, as the oceans absorb and process anthropogenic greenhouse gases.

As the atmospheric carbon dioxide dissolves in water, it forms carbonic acid and causes the pH value of the oceans to drop, posing challenges for many species that live on the cusp of a delicate chemical balance. Continue reading

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