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Research cruise off California finds life lacking in parts of the ocean

Deborah Sullivan Brennan, The San Diego Union-Tribune on

Published in Science & Technology News

SAN DIEGO -- In parts of the California Current this summer, the ocean was clear, azure and almost empty.

The high water clarity and low biological productivity were some of the defining features that struck scientists returning from a cruise with the California Cooperative Oceanic Fisheries Investigation (CalCOFI) program, a 70-year study of West Coast waters.

Although the lack of life sounds ominous, scientists said it's neither good, nor bad, but an interesting observation that will add to their knowledge of the California Current.

"I have never seen the water so blue in my life," said Dave Griffith, a fisheries biologist with the National Oceanic and Atmospheric Administration. "It was beautiful. It looked like Lake Tahoe out there. You don't have upwelling, which is what brings the nutrients up to the surface."

A joint venture of Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration, and the California Department of Fish and Wildlife, CalCOFI was launched in 1949 as a way to understand the collapse of the once prolific sardine industry in California.

It soon expanded to become an exhaustive catalog of fisheries, marine ecosystems and water chemistry. Its quarterly research cruises capture a trove of data about what the ocean is like now, and how it compares to conditions decades ago.

 

The ocean serves as a vast factory for manufacturing life, with plankton nourishing crustaceans and small fish, which in turn support marine mammals, seabirds, sharks and tuna. This summer, that production system seemed to be on pause, researchers said.

"Productivity conditions were very low, we weren't capturing high biomass in any of our nets," said Natalya Gallo, a postdoctoral researcher with the program, who volunteered on the cruise. "Marine mammal observations were low. That makes sense, because you have more animals when you have more food."

Without the churning of nutrients from the ocean floor, the system stalls and ocean productivity -- the amount of life produced at all those levels -- declines.

That's normal in the summer, when warmer water slows up-welling of nutrients from the sea floor, but researchers said ocean productivity seemed lower than usual, even for the season.

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