Ocean Acidification

"The IPCC Sixth Assessment Report concluded that “[t]here is very high confidence that open ocean surface pH is now the lowest it has been for at least 26 kyr [thousand years] and current rates of pH change are unprecedented since at least that time.” As the pH of the ocean decreases, its capacity to absorb CO2 from the atmosphere also declines."

"Besides affecting oysters, ocean acidification can dissolve the aragonite (a form of calcium carbonate) shells of pteropods, tiny marine snails that swim through the water column, and which whales, seabirds and fish rely on as a food source. Acidification slows corals’ ability to grow their skeletons. Marine animals like sea urchins find it more difficult to reproduce. New research has also shown that ocean acidification can exacerbate other issues, including marine heat waves, compounding stress on an already stressed-out ocean. Ocean acidification is considered to have such wide-ranging global impacts that scientists have designated it as one of nine planetary boundaries responsible for regulating and maintaining Earth’s functionality."

"The Arctic is a bellwether for acidification, oceanographers say. Since the Industrial Age, the planet’s oceans have stored up to 30 percent of human CO2 output, with cold polar waters, in which the gas is the most soluble, absorbing the lion’s share. Those same cold waters and unique environmental conditions make the Arctic especially susceptible to the rapidly shifting ocean chemistry wrought by that excess carbon. The result: rising acidity, which eats up the minerals vital to shell-building creatures, as well as posing other dangers to Arctic marine life. . . Models predict that large parts of the Arctic will cross this threshold as early as 2030, and researchers forecast that most Arctic waters will lack adequate aragonite for shell-building organisms by the 2080s.”

"Acidification is underway throughout the world’s oceans, according to a new Oceans and Cryosphere report by the Intergovernmental Panel on Climate Change. But the various ocean regions will respond differently to the same amount of carbon dioxide, says Alessandro Tagliabue, a University of Liverpool biogeochemist and one of the lead authors on the ocean changes chapter of the report. As our carbon emissions continue to soar, acidic conditions will race across the high latitudes first, according to the report. . . “The polar regions are especially vulnerable because of a systemic vulnerability that is linked to their chemical states today, which makes them very, very close to tipping over the edge into extremes of acidification,” says Tagliabue."

Researchers divided waters off the United States into 23 “bioregions” — and found that 16 will face dangerous ocean acidification or at least one force that could amplify it. And most of these 16 regions — especially areas in the Atlantic and the Gulf of Mexico — have economies and cultures that depend heavily on shellfisheries. In the Pacific Northwest alone, acidification is already believed to have cost the seafood industry at least $110 million and affected at least 3,000 jobs.

A new study published in Nature Climate Change warned fisheries producing oysters and clams across the United States will be "vulnerable" in the coming decades to ocean acidification… "In turn, what makes it more difficult for mollusks, crabs and corals to grow their shells."

The Fisheries Climate Science Strategy released by the National Oceanic and Atmospheric Administration (NOAA) is a step to better manage American fisheries in the face of a changing climate. It's a commitment by NOAA to get ahead of the game and establish the structures (information and tools) and support (partnerships) it will need to better manage fisheries in a changing world.

"Unfortunately, the biggest tipping point, the one at which the ecosystem starts to crash, is mean pH 7.8, which is what we're expecting to happen by 2100… So that is rather alarming."

More than a dozen projections by the International Panel on Climate Change indicate that ocean pH by the end of the century could drop as low as 7.8, which would correspond to a 150% increase in acidity since preindustrial times. “A drop of that magnitude is more than we've seen in 20 million years" "That's going to profoundly change the ecology of the sea as we now know it, in ways that could potentially be devastating.”

Alaskan coastal waters and the Pacific Northwest are more acidic because the colder water holds more carbon dioxide. Other contributing factors intensify the rate of acidification. For example, the pH in the lower part of the Chesapeake Bay is declining at three times the overall rate of the Pacific Ocean, and this is in part due to the massive amount of nutrient runoff from farming and industrial chicken production.

 The oyster industry recovered in part by installing monitoring systems in hatcheries that ensure the waters are safe for their oyster larvae. "Oyster hatcheries here are chemically buffering their waters to reduce the corrosiveness, exploring ways to reduce other stressors on the organisms in the hatcheries, and developing breeding programs to help find strains that are more resistant to ocean acidification. Ultimately we need to remove the primary causes of ocean acidification if we value shellfish for their economic and ecological roles."

"The building of skeletons in marine creatures is particularly sensitive to acidity. Under exposure to increasing carbon dioxide in  water, it becomes more difficult for organisms to build shell." As humans throw off the delicate water chemistry that shelled seafood species, such as oysters, scallops and clams, are accustomed to, it'll become harder for them to survive because they'll struggle to build or maintain their shells. The study documents for the first time the links among shell formation rate and sensitivity to acidification.

"..to make matters worse, German and Japanese researchers recently increased CO2 levels in seawater and found that the greenhouse gas can damage some marine organisms directly: Squid slowly asphyxiated as the excess CO2 crowded out oxygen in their blood, and fish embryos and larvae were abnormally small and less likely to survive"

In 2005, the National Oceanic and Atmospheric Administration began reporting that hatcheries throughout the West Coast were seeing steep declines in production, putting the $84 million industry in jeopardy. Hatchery staff and scientists scrambled to pinpoint the cause, and extensive water monitoring was carried out up and down the coast. Bacteria, pollution, and disease were all considered—and ruled out—as possible culprits. “We didn't know what we were dealing with,” says Barton, who has a degree in oceanography. “Everything was dying. [We have] seen a lot of dead larvae, but this time the symptoms were really different.” "The pH level of the water was drastically lower (more corrosive) than usual."