Saturday, May 10, 2014

Climate change's evil twin, ocean acidification: chickens come home to roost.

The largely untold story of CO2 and climate change is, of course, ocean acidification: It’s here, now an starting to kill off marine life.

The oceans cover most of the Earth’s surface, and the oceans have taken up vast amounts of the carbon-dioxide pumped into the atmosphere by fossil fuel burning, deforestation and other activities.

Those chickens are coming home to roost. 

(Image: Ocean acidification is eroding the shells of a key tiny sea creature, the pteropod. The name means wing-foot, and refers to its split foot, which it uses like tiny flippers for movement. Credit NOAA.)

Mix CO2 with water and you get carbonic acid. It happens in a Coke bottle. And it happens in the laboratory. And sure enough, it happens in the ocean. The oceans have become more acid. And what does that matter?

Have you ever thrown a piece of seashell (alkaline) into a dish of vinegar (acid)? Try it. The shell sizzles and pops and eventually disappears.

The loss of shell-forming marine life was an early prediction about climate change. Now, it’s happening.

A study released May 1 shows that the shells of a small sea snail are dissolving. 

“We found 53% of onshore individuals and 24% of offshore individuals on average to have severe dissolution damage,” wrote the authors of this paper, referring to pteropods—a group of free-swimming deep-ocean sea snails.

 Here’s an easier-reading NOAA report on the same study.

Hawai`i has actually benefitted in one small way from acidification. Due to higher-acidity in upwellings off the West Coast, an oyster farming company moved its oyster hatchery to Hawaii. This story in theSeattle Times said: “Carbon dioxide from fossil-fuel emissions had turned seawater in Willapa Bay along Washington’s coast so lethal that slippery young Pacific oysters stopped growing.”

They can still grow the adult oysters in Washington waters, but the animals have trouble reproducing there.

In the Islands, there is concern that our coral reefs are at risk. Corals, after all, are made of calcium carbonate, an alkaline material that also makes up oyster and pteropod shells.

The National Climate Assessment’s Pacific section includes these words:

“The amount of calcium carbonate, the biologically important mineral critical to reef-building coral and to calcifying algae, will decrease as a result of ocean acidification. By 2035 to 2060, levels of one form of the mineral (aragonite) are projected to decline enough to reduce coral growth and survival around the Pacific, with continuing declines thereafter.”

Not to be too hysterical about this, if Hawai`i’s coral reefs begin dissolving, the potential impacts are severe: lost habitat for reef fish, lost snorkeling opportunity, disappeared surf breaks, lost coastal protection from wave can think of others.

© Jan TenBruggencate 2014

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