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Digging in the Deep For Clues to Climate

Scientists take rock and sediment samples from far beneath the ocean floor to determine future atmospheric patterns

By Alexander MacLeodSpecial to The Christian Science Monitor / February 5, 1992


SCIENTISTS are delving deep under the ocean floor and uncovering clues to changes in the earth's climate.

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In the waters of the eastern Pacific, they have just drilled their deepest-ever hole and are studying samples of rock and sediment millions of years old, hauled up from more than three miles beneath the surface of the ocean.

Members of the worldwide Ocean Drilling Program (ODP) hope that the samples will provide pointers to what the world's atmospheric patterns may be like decades and centuries from now.

Already the world's largest and most successful multinational earth-science research effort, ODP is gearing up to extend its researches to the North Atlantic next year.

Paleoceanographers and other scientists aboard ODP's research ship, JOIDES Resolution (the name stands for Joint Oceanographic Institutions for Deep Earth Sampling), have already produced evidence suggesting that theories on global warming will have to take account of climatic rhythms extending back into our planet's prehistoric past likely to be replicated in the future.

Lin Kay, an earth scientist with Britain's National Environmental Research Council (NERC), which is a major ODP participant, describes the work as "extremely important and exciting."

"The past not only tells us about the present - it offers us a guide to the future. By digging into rock deep beneath the ocean and looking at the story it tells, we are learning a great deal about global climate patterns," Dr. Kay says.

Following limited ocean drilling that began in 1968, the current $36-million program was launched nine years ago with an emphasis on reconstructing the fundamental mechanisms that created ocean basins, island chains, and mountain ranges.

Ocean drilling in the 1970s produced important information about the makeup of the 70 percent of our planet covered by water. An early achievement was recovery of a fragment of the oldest remaining sea floor - a relic of the middle Jurassic period 170 million years ago. At that time, one vast ocean covered the planet, the continents formed a single huge cluster, and global temperatures were much warmer than today.

ODP's early members included the United States, France, West Germany, Britain, and the former Soviet Union. The latter's membership is now in doubt, but other countries, including Japan and Australia, are becoming involved.

The US National Science Foundation funds ODP along with significant contributions from 19 countries. Texas A&M University in Galveston, Texas, is the program's science operator.

Once you get under it, the seabed is a happy hunting ground for earth scientists. On dry land, rocks can be more than 3 billion years old. Under-ocean rock is only 200 million years old. This is because it is constantly being replenished by volcanic activity, especially where the seabed meets the edges of continents.

In the last four or five years, Kay says, ODP's emphasis has swung toward probing links between seabed geology and the world environment. Concern about depletion of the ozone layer has been a driving force behind the switch of focus.

ODP research depends on the fact that all the time, anywhere on the earth, the effects of climate are being felt. In the sea, plankton take carbon dioxide (CO2) out of the air and are later fed on by larger creatures that fall to the seabed and die. The CO2, an important gas in global warming, remains locked in their tissue.