11 July 2005

Scientists check the ocean's pulse

Nearly 500 miles off San Diego, night has shrouded the ocean, but electric lights illuminate the research vessel New Horizon.

Scripps graduate student Jamie Holte lowered the CTD while on a research trip off the Southern California coast in April. The conductivity, temperature and depth instrument aboard the New Horizon helps scientists study ocean chemistry.The ship's scientific team lowers a deep-sea monitoring instrument tethered to a steel cable. It descends into the abyss, relaying changes in temperature, salinity, water density and oxygen, and chemicals that offer clues to the abundance of life in the darkness.

At this lonely spot in the Pacific, researchers on the New Horizon and other ships have monitored the ocean since 1949. The station and 65 more along the survey route off California make these waters the most studied stretch of sea anywhere.

"There's nothing else like it in the world's oceans," said John McGowan, an oceanographer with the Scripps Institution of Oceanography in La Jolla who has helped to conduct the surveys for five decades.

Studies of marine ecosystems, such as surveys of the California Current from San Diego to north of Santa Barbara, are gaining unprecedented prominence as state and federal officials debate how best to preserve the world's oceans.

Tracking the currentIn Sacramento, the recently formed California Ocean Protection Council is tackling issues ranging from offshore oil drilling and marine refuges to bay restoration projects and control of river sediment.

In Washington, the House and Senate are debating a new national ocean policy – the first such review in 36 years. Dozens of ocean-related bills have been introduced during this year's congressional session.

The sweeping attention follows the release of two landmark reports, in 2003 and 2004, that found America's coastlines are polluted, overfished and neglected. The studies, by the private Pew Oceans Commission and the presidentially appointed U.S. Commission on Ocean Policy, called for urgent efforts to protect these waters.

The U.S. commission made more than 200 recommendations toward that end, but President Bush has acted on few of them and offered little funding for the panel's proposals.

Whatever changes government might enact, everyone seems to agree that without sound science, lawmakers will be hard-pressed to prevent overfishing, control pollution, preserve endangered marine habitats and regulate offshore drilling, fish farming and commercial shipping.

"It is a time when momentum is peaking," Adm. James Watkins, former chairman of the U.S. Commission on Ocean Policy, said of the recent attention given ocean issues in the nation's capital. "We've got a lot of enthusiasm back here. We've got good rhetoric. Let's get some teeth in that rhetoric now."

A broader approach
People debating a new national ocean policy also have found common ground on this basic point: Regulating human impacts on the sea requires research that considers entire ecosystems. In other words, scientists accomplish little if they study one type of zooplankton, fish or whale without considering the larger world in which it lives.

The California Current offers scientists a huge world to examine.

The current flows across numerous jurisdictional boundaries, including state, federal and international waters. Managing its resources requires immense coordination, said John Orcutt, deputy director for research at Scripps.

The CTD, or conductivity, temperature and depth monitor, nears the end of a journey that took it nearly 1,700 feet below the surface. It is the Scripps Institution of Oceanography's prime instrument for studying the ocean's chemistry."When you're trying to regulate things like (commercial fisheries) . . . you have to go to the scale of the ecosystem, not just the political boundaries," Orcutt said.

"Political boundaries don't mean much to fish."

Scientific surveys off Southern and Central California conducted by Scripps and the federal Southwest Fisheries Science Center, also in La Jolla, have yielded key insights about marine life.

The discoveries include how El Niños – periodic warming of waters in the eastern Pacific that bring heavy rains to the West Coast – drive changes in the ocean's food web. The observations also offer clues about how global warming may be altering ocean chemistry and sea life.

Armed with stacks of data, researchers have painted an increasingly clear picture of the California Current – which begins off Washington state and flows south along the coast – and the plankton, sardines, tuna, dolphins, sea lions, whales and other creatures that swim in it.

The Scripps and Fisheries scientists are about to collaborate with other groups to broaden their research dramatically. In a few years, their ship-based surveys off California will be linked with separate ocean studies off Baja California, Northern California and the Pacific Northwest. Likewise, scrutiny of coastal waters immediately offshore will be combined with the California Current surveys.

Last fall, Scripps launched an additional long-term study of the plants and animals that live in the current. The project will be funded for the first six years with $5 million from the National Science Foundation.

When taken together, these studies will give the public, including policy-makers, a groundbreaking picture of the West Coast's largest ecosystem.

Crossing the current
Studying the current requires going to sea.

Four times a year, on surveys that last about three weeks, a ship from the Scripps fleet or the National Marine Fisheries Service embarks from San Diego and crisscrosses the California Current.

Every 40 nautical miles along the route, the ship stops and its scientific crew drops three nets over the side – each to a different depth. Zooplankton captured in the nets help scientists track these organisms critical to the ocean's food web. Collected fish eggs help them estimate the abundance and vitality of numerous fish species.

During night operations aboard the research vessel New Horizon in April, Shonna Dovel and Fernando Ramirez checked the ship's primary scientific instrument, the CTD. The device is plunged into the ocean and scientists trigger the lid of each bottle to snap shut at various depths. Technicians and scientists collect the water samples for later examinationAt every station, a deep-sea monitoring instrument called the CTD – short for conductivity, temperature and depth – descends nearly 1,700 feet. Electronic instruments within it record temperature, conductivity, density, oxygen and concentrations of chlorophyll. Changes in electrical conductivity correlate with changes in salinity, while chlorophyll concentrations give clues about the abundance of phytoplankton.

On a New Horizon survey in April, researcher Fernando Ramirez settled into a lab chair tethered with bungee cords to keep it in place in the steadily rolling ship. The ship's lab was an organized jumble of computers, cabinets, cables, glass jars and microscopes – all mounted or tied down.

While the CTD descended into the ocean, Ramirez watched as plots on his computer screen drew a profile of the ocean. Temperature and oxygen concentrations fell precipitously as the instrument passed 330 feet. Simultaneously, water density and salinity climbed.

After about 15 minutes, the instrument was raised slowly. Two dozen plastic bottles mounted to an aluminum frame collected water at predetermined depths. Researchers analyzed this water aboard ship.

The New Horizon carried 29 people – 12 crew members and 17 highly trained technicians who gather plankton and fish eggs, record data on ocean chemistry and log observations of marine mammals and birds.

For Dave Wolgast, 45, the trip's chief scientist, the lure of the sea hooked him early. He loved watching "The Undersea World of Jacques Cousteau" as a boy, and he read every diving book he could find at his grade school.

Environmental surveys of the sea, by definition, are laborious and repetitive.

"It's important not to let the repetition burn you out, so that you can continue to collect accurate data," Wolgast said.

The ocean off Southern California can get rough, particularly in the winter and spring. Prevailing winds blowing from the northwest can exceed 30 knots and drive swells 15 feet or higher.

Some 500 miles out, the Pacific offers a startling blue denied to people on shore. The light of a passing day can shift that color moment to moment. Under a full moon, the sea sparkles.

Dolphins congregate in the current by the hundreds, launching themselves into the air with bursts of energy. In the Anacapa Passage, between the rugged Santa Cruz and Anacapa islands off Ventura, sea lions lounge in the sun, floating on their backs as a swift current carries them out to sea.

Survey origins
Ocean surveys off California began 56 years ago when researchers set out to determine why Pacific sardines had nearly vanished from coastal waters.
Scientists discovered that natural cycles in the California Current send fisheries on roller coasters of abundance and scarcity. Commercial fishermen, lacking this knowledge in the 1930s and '40s, had ravaged populations of sardines that had already started a natural decline.

Solving the sardine mystery was an early achievement, one that reflected a new understanding of the forces shaping life in the ocean.

The studies became known as the California Cooperative Oceanic Fisheries Investigations, or CalCOFI.

Connecting natural ocean cycles to the health of fisheries has proven invaluable for the federal government. The CalCOFI program's insights have helped the Pacific Fisheries Management Council regulate how much fish commercial fishermen can take from the ocean, and those decisions have helped the sardines recover and protect other species.

"Those long-term data trends are often very, very important in determining what's going on . . . now," said Mike Burner, a manager with the Pacific Fishery Management Council in Portland, Ore.

CalCOFI, which receives about $3 million annually from the state and federal governments, helped transform oceanography in the 20th century.

For the first time, scientists sought to comprehend the sea's currents, chemistry and biology. Before the 1950s, scientists generally studied a particular fish or a particular place, such as deep-sea trenches, in isolation.

The California Current is part of the giant clockwise rotation of water in the north Pacific Ocean.

It swells with life, from microscopic plankton to the largest whales. Its vitality has much to do with the rotation of Earth. The current, flowing north to south, is deflected from North America as the Earth rotates west to east.

The current's retreat from the coastline draws water toward the surface. This brings nutrients from the depths that phytoplankton – fundamental in the ocean's food web – use to grow.

As phytoplankton multiply, they're eaten by tiny zooplankton. The health of zooplankton is critical to the small fish that eat them in turn and, by extension, to all sorts of marine life – larger fish, dolphins, sea lions and whales.

During their studies, CalCOFI scientists have observed perplexing changes in plankton populations.

Higher temperatures in the California Current, brought about by El Niños, suppress populations of zooplankton. But for reasons unknown to scientists, phytoplankton appear unaffected.

Ralf Goericke, a senior CalCOFI scientist, is counting on Scripps' new long-term study of the current to yield some answers.

"CalCOFI . . . has given us great insights into what is happening out there . . . but we don't know why," Goericke said.

Obtaining a clearer picture requires a whole new kind of science that tries to understand biology on gigantic scales – the size of something like the California Current, the Pacific Ocean and the entire globe, scientists say.

The half century of studies compiled by CalCOFI surveys approach science at that kind of scale, but more insights are sure to come.

"They'll allow the government to make more informed decisions," said McGowan, the Scripps oceanographer, "and allow the public to make judgments about what kind of world they want to live in."

Source: www.signonsandiego.com


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