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Dr. Barney Balch with team of researchers aboard the R/V Revelle. Balch, who is standing center, first row with a black shirt on, helped lead the month-long voyage to the equatorial Pacific Ocean to investigate phytoplankton activity.

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Tracking an essential source of life the world over

Ocean voyages hope to find clues to climate change                  Printer friendly format

By Steve Cartwright

If the health of the sea seems remote to your well-being, consider this: phytoplankton, the single-celled algae that are the most abundant photosynthetic organisms in the ocean, produce half the oxygen in the atmosphere via photosynthesis. Trees, shrubs, grasses and other plants produce the other half via photosynthesis. Therefore, says Dr. Barney Balch, senior research scientist at the Bigelow Laboratory for Ocean Sciences in Boothbay Harbor, Maine, “Every other breath you take is thanks to phytoplankton.”

Just back from one of his numerous oceanic study cruises, Balch says that in the big picture, we ignore the marine environment at our peril. He is fond of a Garry Trudeau cartoon that cites the “save the whales” battle cry, but wonders where the “save the phytoplankton” troops are.

Balch is concerned that only half of industrial carbon dioxide emissions can be found in the atmosphere. That means the other half must be sinking into the sea, which covers three quarters of our planet. Recent reports show that while carbon dioxide has been increasing since the Industrial Revolution that began in England at the end of the 18th century, half of all emissions have taken place since 1980. Human-made carbon dioxide has been found in the ocean to depths of 1,000 meters.

“Carbon dioxide levels are higher than they’ve been in geological time, or millions of years,” he says. “If you dissolve carbon dioxide in water, you’re making it acidic. If you start to acidify the ocean, that could have amazing impacts on everything from the physiology of animals and plants to the survival of phytoplankton.”

Phytoplankton and carbon

Phytoplankton form the base of the food web in the seas and remove the greenhouse gas carbon dioxide from the atmosphere. By studying a calcifying phytoplankton called coccolithophores, Balch hopes to better understand the ocean’s role in the global carbon cycle and its relation to global climate change. Referred to by scientists as a beneficial phytoplankton, coccolithophores sequester significant amounts of dissolved carbon in surface waters, converting it to a protective shell of calcium carbonate. After the plants die, Balch explains, calcium carbonate sinks into the deep sea, generating about one quarter of all the marine sediments on Earth.

Also known as limestone, calcium carbonate acts like miniature antacid tablets buffering the ocean’s acidity to a neutral range. As human-produced carbon dioxide from fossil fuels works its way into the sea, coccolithophore calcite helps stabilize the ocean’s acidity, keeping it from increasing to unhealthful levels.

Balch and his colleagues recently returned from a month-long voyage to the equatorial Pacific Ocean to investigate how carbon dioxide is being cycled between the atmosphere and ocean. Emissions of carbon dioxide are significantly high in the region. It is also an area of intense upwelling and high concentrations of nutrients. These two factors should encourage algae production, yet biomass is low. Balch suspects some of the reasons for the low productivity include the limited availability of iron or silica acid, which would stimulate growth.

Another possibility is intense grazing of phytoplankton by microzooplankton. As he explains it in his travel log of the voyage, “Imagine a highly productive field that is being regularly mowed so the biomass of grass remains low, even though it is still highly productive.”

Last fall, Balch participated in a six-week, British-sponsored voyage, with National Aeronautic and Space Administration (NASA) funding, from Southampton, England, to Cape Town, South Africa. A major finding of the trip, Balch says, was confirmation of a great band of high concentrations of suspended calcium carbonate, presumably from coccolithophores. Balch says evidence of this band, repeatedly seen in global satellite images, had never been validated from a ship.

Mostly work and little play

On this voyage, scientists from different parts of the world traveling with Balch studied a variety of currents, upwellings, winds and variations in phytoplankton biomass. The trip had more than a few tense moments. One day the diesel-electric engines that throb continuously, thrusting the ship ever onward, came to an abrupt halt after all four generators failed. An odd silence ensued, as scientific instruments, cooking, even toilet flushing stopped. Engineers eventually got things running again. A lesser crisis involved the ship needing refrigerant, essential for work in the hot, equatorial climate. The ship put into Tenerife, one of the Canary Islands, for just four hours, with no shore leave granted, even for Spanish scientists craving a fresh espresso.

All this effort will help answer questions such as, “Are our oceans getting warmer?” If they are, it could be part of global climate change and it could mean drastic changes in habitat and species affecting commercial fishing. Such subtle things as Arctic oscillation—the global forces that ultimately drive winds in our tiny Gulf of Maine —are studied to determine changes over decades.

“We’re not just an isolated body of water here in the Gulf of Maine,” Balch says. “Very large-scale climatic changes affect the mixing in our gulf, which affects the phytoplankton and zooplankton all the way up to the upper trophic levels on which we humans rely.”

Balch’s federally funded research trips are basically work and not much play. On his voyage to the equatorial Pacific, he started a typical day at 1:30 a.m., worked till 9 a.m., took an hour’s nap, worked till dinner, practiced jazz trombone for a half-hour, and turned in about 8 p.m. The ship, and the work on board, continues 24 hours a day. A welcome diversion was stopping at a National Oceanic and Atmospheric Adminstration buoy near the Equator, which acted as a fish magnet, and Balch and others caught enough Wahoo and tuna to feed all hands for two dinners, plus make sushi.

There were moments of beauty, too. Balch wrote in his log: “During our steam to Tahiti, there were clear skies and no moon early in the evening, which provided the most spectacular star-gazing of the trip. My New Year’s Eve was spent on the forepeak of the Revelle, picking out constellations and watching spectacular bioluminescence in the bow wake.”

Balch said we comprehend only a small percentage—perhaps five percent—of the inner workings of the world’s oceans. That leaves scientists with a long way to go. Balch and company have embarked on that voyage, traveling vast distances to study some of the smallest things in the sea. “These organisms have such a profound effect, not just on people, but on the whole biosphere,” he says.

To read Balch’s ship’s logs, and find out more about Gulf of Maine research projects, visit http://www.bigelow.org.

  © 2005 The Gulf of Maine Times