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‘Weird’ hunt
for UH team

The 'biggest, oddest place
in the upper ocean' could yield
greenhouse gas clue

By Helen Altonn
Star-Bulletin

UNIVERSITY of Hawaii scientists this summer will investigate what they say is the weirdest spot in the ocean and try to figure out how it contributes to greenhouse gases.

They plan to follow a plume of oxygen-deficient water from Hawaii to the eastern tropical North Pacific.

The region south of Guadalajara, Mexico, "is really a bizarre part of the ocean with strange chemistry," said Brian Popp, associate professor of geology and geophysics. Instead of normal 100 percent oxygen saturation, the level drops to zero within about 200 feet of the surface, he said.

"This is certainly the biggest, oddest place in the upper ocean anywhere -- a huge area of the ocean where all oxygen has disappeared from the water," said Frank Sansone, associate professor of oceanography. Popp and Sansone, leaders of the scientific cruise, are concerned about methane and nitrous oxide gases that cause global warming in the atmosphere and normally are produced under low oxygen conditions.

By Ken Sakamoto, Star-Bulletin
'This is certainly the biggest, oddest place
in the upper ocean anywhere -- a huge area
of the ocean where all oxygen has
disappeared from the water.'
Frank Sansone
Oceanography professor, who with fellow
University of Hawaii scientist Brian Popp, left, will board
the scripps Institution ship Revelle to track down
a plume of weird water.

A 20-member scientific party will leave tomorrow on the Revelle, flagship of the academic fleet operated by the Scripps Institution of Oceanography. The trip will end July 28 in San Diego. Peggy and Nathaniel Ostrom, Michigan State University biochemists, will join the UH scientists and students.

Popp said Hawaii has an "oxygen minimum zone" at a depth of about 2,640 feet, where oxygen concentrations drop to about one-fourth of the surface level.

MOVING closer to Mexico's coast, low oxygen waters are much shallower and oxygen depletion becomes more intense, he said. It is there that the scientists expect to find more production of the "greenhouse" gases, particularly nitrous oxide (used in anesthesia and aerosols).

He said the upwelling of nutrient-rich deep water along the west coast of Mexico and the rest of Central America is wonderful for plants and creates great fishing grounds.

But as the plant material dies and decomposes, it consumes all the oxygen from the atmosphere and "creates very unusual conditions."

Sinking particles of phytoplankton and biological debris stick together and form layers, producing what is called "marine snow," Sansone said.

Large layers of marine aggregates extend for hundreds of miles but little research has been done on them, he said. "This is one of the things bugging me ...

"Everyone knows nitrous oxide and methane are in the upper ocean, but no one has ever been able to determine how and where they form.

"I think they're forming on the particle layers, but no one knows for certain."

The researchers will lower bottles from the ship to sample the waters.

Their work should tie in with work done the past few years by UH oceanographers David Karl and Roger Lukas at Station ALOHA, about 60 miles off Oahu.

The Revelle will make a one-day stop at the station to gather data to compare with the "weird environment that we're going to," Sansone said.

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Ka Leo O Hawaii