Arctic Basin - "Nowhere On Earth Have We Documented Such Large-Scale, Rapid Ocean Acidification"

[hatrack]

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Ocean acidification is the process by which pH levels of seawater decrease due to greater amounts of carbon dioxide being absorbed by the oceans from the atmosphere. Currently oceans absorb about one-fourth of the greenhouse gas. Lower pH levels make water more acidic and lab studies have shown that more acidic water decrease calcification rates in many calcifying organisms, reducing their ability to build shells or skeletons. These changes, in species ranging from corals to shrimp, have the potential to impact species up and down the food web.

The team of federal and university researchers found that the decline of sea ice in the Arctic summer has important consequences for the surface layer of the Arctic Ocean. As sea ice cover recedes to record lows, as it did late in the summer of 2012, the seawater beneath is exposed to carbon dioxide, which is the main driver of ocean acidification. In addition, the freshwater melted from sea ice dilutes the seawater, lowering pH levels and reducing the concentrations of calcium and carbonate, which are the constituents, or building blocks, of the mineral aragonite. Aragonite and other carbonate minerals make up the hard part of many marine micro-organisms’ skeletons and shells. The lowering of calcium and carbonate concentrations may impact the growth of organisms that many species rely on for food.

The new research shows that acidification in surface waters of the Arctic Ocean is rapidly expanding into areas that were previously isolated from contact with the atmosphere due to the former widespread ice cover.

"A remarkable 20 percent of the Canadian Basin has become more corrosive to carbonate minerals in an unprecedented short period of time. Nowhere on Earth have we documented such large scale, rapid ocean acidification" according to lead researcher and ocean acidification project chief, U.S. Geological Survey oceanographer Lisa Robbins.

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http://www.enn.com/top_stories/article/46415

[GliderGuider]

1. So it goes. nt

[Judi Lynn]

2. Sad. The earth needs protection, now. n/t

[CRH]

3. The Arctic is changing faster than much of the globe, ...

but the acidity problem is fast being realized as a global problem.

In November 2008 studies began to surface about acidity in the Southern Ocean.

Scientists had thought a 550 ppm atmospheric CO2 level would be near a tipping point but have since lowered the estimate to 450 ppm, warning this level could be reached as early as 2030.

With the krill population in the Southern Ocean reduced by 85% in the last 30 years, the ecosystems are already tilting toward collapse.

The Southern Ocean gets less publication and attention, but the problem with the oceans is global.

http://www.cosmosmagazine.com/news/southern-ocean-dangerously-acidic/

“Our new results point to irreversible and detrimental impacts to Southern Ocean marine calcifying organisms if atmospheric carbon dioxide exceeds 450 ppm [parts per million],” said Ben McNeil, who led the team from the University of New South Wales and government research agency the CSIRO.

Tipping point

Previous work had suggested that the tipping point wouldn’t occur until atmospheric carbon dioxide (CO2) passes a concentration of 550ppm, which some climate models predict will be happen by 2060. The revised estimate is published this week in the U.S. journal, the Proceedings of the National Academy of Sciences.