Ocean acidification is extremely underestimated, scientists accidentally discover – Haaretz

Africa is right there, and medieval Europe knew that. They just didn’t know the details until explorers boldly went to where no European had gone before, at least as far as anybody knows. Now, scientists at Ben-Gurion University of the Negev have made a discovery while researching characteristics of the blood that had been right under our nose, as lead researcher Prof. Ehud Pines from the Department of Chemistry tells Haaretz. “We just didn’t realize exactly how important carbonic acid is in regulating the acidity of our blood — and of the oceans,” he says.

Ocean acidification is a clear and present danger to marine life, to the marine food chain and to animals that eat marine life (such as ourselves).

Ocean acidity differs vastly on a local scale. But looking at the global average, the world’s oceans are about 25 percent more acidic than before the industrial revolution.

To those of you who took chemistry once upon a time, the pH of the ocean is presently about 8.1. The pH of our blood averages about 7.4, by the way.

Now Pines and his team demonstrate that ocean acidification studies and projections have failed to factor in a key element that could make it all happen much faster than is presently realized. Yet again, the culprit is the huge increase in atmospheric carbon dioxide in the industrial age, which has caused a huge increase in the amount of carbon dioxide dissolved in the oceans. And that in turn causes a huge increase in oceanic carbonic acid.

Blood ties

The problem, Pines explains, is that the carbon dioxide (CO2) molecules in the sea react with the water molecules (H2O). The reaction forms carbonic acid: H2CO3. 

The more CO2 gets absorbed by the oceans, the more carbonic acid is formed.

We have known about this since we were knee-high to a test tube. Why has carbonic acid been totally ignored until now? Because it is extremely unstable, so the thinking was that if a carbonic acid molecule blinks into existence and promptly blinks out again, we can ignore it.

But we can’t.

“The only thing everybody talking about climate change can’t argue about is the concentration of carbon dioxide in the air,” Pines tells Haaretz. “And they can’t argue that when it enters the water, it creates more carbonic acid in the water.”

Gulf of Eilat
All sea life, and certainly calcium-dependent animals like coral, are sensitive to ocean acidification.Prof. Maoz Fine

When carbonic acid “blinks out,” that is a euphemism for “breaks down into carbon dioxide and water again.” But that isn’t the point. The point is that while it exists, it is an acid. And while one molecule may arise and fall and nary a scientist will notice, bajillions of them being formed at any given moment — and the numbers are growing by the day — have a collective effect.

That collective effect is to render the oceans more acidic. And that is the thing under our noses: Massive and growing creation of carbonic acid in our oceans, which Pines says must be factored into the projections.

Carbonic acid formation — whether in our vascular system or the seas — was left unmolested by measurement because until recently it was difficult to track reactions that fast, Pines adds. Now we can.

Evidently, it took not a village but a physical chemist to make the leap from a study focusing on blood acidity regulation to the future of the oceans.

“I look at systems from above — grosso modo,” Pines explains. “It was clear to me that [blood and the oceans are] the same system and they have the same carbonic acid in water. Carbonic acid is the universal acidity regulator. What could be more universal than having the same regulation system in our blood and in the oceans … and no wonder it maintains fixed acidity in about the same place in the sea and blood.” Both are on the basic side.

A molecule named Sue

Apropos the blood, the team’s discovery was just as startling to those in the know about hematopoietic biology. “Physiology textbooks will have to be modified,” the researchers state. But why?

In the seas, carbonic acid is created when water and CO2 mix. In our bodies, it is created when bicarbonate in our blood, which helps regulate our CO2 output and to regulate blood acidity, mixes with acid, any acid. The thinking had been that the resultant carbonic acid is too ephemeral to affect blood chemistry.

But Pines and the team showed that even though each carbonic acid molecule may survive just milliseconds, in that short lifetime it behaves like an acid. It turns out to be a key source of protons for biological reactions, and evidently plays a much more significant role than had been appreciated. Including in blood acidity regulation.

“The acid’s instability doesn’t affect its activity as an acid,” Pines tells Haaretz. “Biological systems don’t care about the individual identity of one molecule. It isn’t that each molecule has a name and number.” It’s all about their concentration and equilibrium.

To sum up, the extra carbon dioxide we’re pouring into our air — emissions are not declining, they are still increasing — is also acidifying our oceans beyond what we had even realized, the BGU team at Be’er Sheva has inadvertently indicated.

Coral can't survive in acid conditions.
Coral can’t survive in acid conditions. (Illustration)Prof. Maoz Fine

It is even possible that carbonic acid has been playing a key role in the decimation of the world’s coral reefs. What we see as gorgeous underwater shapes is actually colonies of calcium-based skeletons of tiny animals. The more acid the water, the weaker their skeletons. And why stop there? Every single sea animal with a shell is in danger, as is everyone dependent on them — from seabirds to oyster fishermen.

As we said, local acidity can vary quite vastly, “The Adriatic Sea, for instance, has tons of plants and lots of freshwater input, so its pH [acidity] is completely different from the Mediterranean,” Pines points out. But the bottom line is the oceans are growing more acidic, and it’s continuing. There is no telling where it will stop. And that is also 100 percent unarguable.