In 2007, scientist Richard Feely of the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory set out on a research cruise off the Pacific Coast. Feely and other scientists were trying to understand how the ocean was changing -- becoming more acidic -- as a result of climate change.

The results, Feely said, were "truly astonishing" (ClimateWire, May 28, 2008).

The ocean, which has absorbed about a quarter of the 2 trillion tons of carbon dioxide emitted by fossil fuel burning, was changing its chemistry far more rapidly than anyone had imagined. Areas of the ocean off the West Coast were at levels of acidity scientists had not thought they would see until 2050.

Now, armed with more knowledge and new hypotheses, NOAA is embarking on a follow-up to that 2007 cruise.

Starting Monday, scientists will sail from Seattle to San Diego, analyzing ocean chemistry, looking at the effects of acidification on small snails called pteropods, and looking for hot spots of toxic algae, whose populations and toxicity may swell as the ocean continues to acidify.

Not good news for the shellfish industry
Just a year after that first research mission, Puget Sound oyster farms experienced population crashes. Young oysters failed to thrive in a more acidic ocean.

Since then, scientists have conducted experiments on the potential impacts of acidification on corals, mussels and sea urchins, among others.

But there's nothing like getting out in the ocean and actually measuring what is happening, said Feely, who will be on this year's cruise as well.

A unique aspect of this research expedition is that biologists will be able to work simultaneously with chemists, he said. Biologists can see what ocean creatures are doing in their natural environment, and chemists can measure the properties of that environment.

One important thrust of this cruise is research into how the pteropods, whose shells dissolve when water is too acidic, are reacting to current ocean conditions. Pteropods are prey for many fish and birds in the ocean ecosystem.

"Pteropods are really an important food source for juvenile pink salmon," said PMEL scientist Nina Bednarsek, who will be studying them on the cruise. "Herring and mackerel depend on them too."

A preview of what other oceans face
Another area of interest for researcher Vera Trainer, of the Northwest Fisheries Science Center, involves investigating whether toxic algae are becoming more poisonous due to acidification.

Laboratory experiments have shown that the algae produce more toxins in more acidic waters. The cruise will allow researchers to see whether they are also producing more toxins in the West Coast ocean water.

These toxins can be concentrated in shellfish as they feed, and the toxin can affect marine mammals and humans who eat the shellfish.

The West Coast is a good place to conduct research on the impacts of ocean acidification.

That is because in the summer, natural upwelling brings acidic water to the surface. It mixes with the increasingly acidic surface water and creates conditions similar to what the rest of the ocean will likely see further into the future, Feely said.

The cruise, which runs from Monday to Aug. 29, will stop on Aug. 14 for two days in San Francisco, where scientists will present preliminary results at the Exploratorium museum.

A cruise blog will be live once the ship sails, at, and the researchers will also be posting updates on Twitter at @OA_NOAA.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC., 202-628-6500