Oceans becoming more acidic, bad news for Northwest seafood industry

Carbon emissions from factories, power plants, cattle farms and other sources are giving the oceans a serious case of acid indigestion, and it’s not curable by desperately throwing TUMS into the waves.

University of Washington oceanographer Jan Newton came to Longview Tuesday to discuss how carbon dioxide emissions are causing “ocean acidificiation” and its consequences on the economy, ecosystems, and the salmon and oyster industries.

“The ocean has so many effects on us, directly and indirectly,” Newton said in an interview following her talk, delivered to about 30 people at Lower Columbia College. “We get a lot of our protein from the ocean. Half the oxygen we breathe comes from the phytoplankton in the ocean. … Ocean acidification … has the capacity to really disrupt food webs.”

Scientists are learning, for example, that ocean acidification may diminish salmon’s ability to sense predators, Newton said. And the rising acidity of seawater has caused disastrous production failures at the Taylor Shellfish hatchery near Quilcene, Wash., and Whiskey Creek shellfish hatchery in Tillamook, Ore., she noted.

When it absorbs carbon dioxide, seawater becomes more acidic (a lowered pH level) and reduces the amount of carbonate in the ocean, Newton said. Carbonate is a basic building block that ocean life uses to make shells and skeletons. Reduced carbonate levels especially affects organisms such as crabs and oysters.

Rising acid levels in the ocean are not a direct hazard to humans, Newton emphasized. “If you dip your toe in the ocean, you’re not going to get an acid burn,” she said. “It’s not acid. It’s acidifying.”

But the way ocean acid levels are measured can be misinterpreted. The earth’s oceans have been slightly basic for the past 300 million years, with a pH level of 8.2. (The pH scale goes from 0 to 14, where lower numbers are acidic and high numbers are basic.) The pH level has dropped to 8.1.

“A change in pH of 1 is a 100 percent (change), and (a change) of 0.1 is 30 percent,” Newton said. Globally, the pH has fallen 0.1 since the Industrial Revolution, which is a 30 percent increase in acidity.

“Small changes in pH mean much larger changes in acidity,” Newton said.

The ultimate solution for ocean acidification is lowering how much carbon dioxide we emit, she said. But scientists are testing several strategies to help lessen the impact of the changing acidity.

One of those projects is growing kelp on rafts. Through photosynthesis, kelp naturally takes up carbon dioxide. Then, the kelp can be taken out of the ocean and used as fertilizer or food, Newton said.

“Right now, there is a football field-sized raft of kelp growing in Hood Canal,” she said.

One lecture attendee asked if dumping antacid into the ocean could work.
“People have looked into that,” Newton said. “And in fact, that is what shellfish hatcheries are doing” to lower the acid level of seawater in their rearing tanks.

The hatcheries use data collected from buoys to monitor pH levels. If the water gets too acidic, they use antacids, except they’re actually called “buffers,” Newton said.

Scientists aren’t sure if these techniques can be used at a large enough scale to make a difference in the ocean’s overall pH.

“I really want to stress what’s on the title here,” Newton said. “It’s a global issue with very local effects.”

Kay Holten, The Daily News Online, 2 March 2018. Article.


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