Science

How ocean research came out of its shell

Rita Christopher January 22 1979
Science

How ocean research came out of its shell

Rita Christopher January 22 1979

How ocean research came out of its shell

Science

How do I love clams? Let me count the ways: fried, baked, steamed, on the half shell, in chowder and now—in the lab. The bushels of clams delivered to assistant professor Ida Thompson at

Princeton University are not to be downed with cocktail sauce and a cold beer; Professor Thompson’s clams make their supreme sacrifice for science, and while that might make for fewer bowls of chowder, it has led to some extraordinary conclusions about a very ordinary mollusk.

The ocean quahog, which Professor Thompson has studied along with other species for the past decade, can live to an age of 150, giving clams the undisputed title of the longest-lived of the invertebrates. Although this species nestles quietly in the sand from 50 to 600 feet below the surface, their lives are far from dull: the clams exist in a

state that men’s magazines can only fantasize about—even at 100 they remain sexually active.

Clams, in fact, seem to live in a watery Shangri-La, devoid of all aspects of

the aging process. “We’re not sure if they ever die of old age. The only ones whose fate we’re certain about are the ones fishermen take,” says Thompson. While no one is ready to predict what animals, man included, can learn about aging from mollusks (except to steer clear of trawlers’ nets), some physiologists are planning microscopic examination of quahog tissue for clues to eternal youth.

To establish her subjects’ longevity, Professor Thompson examines the shells with the aid of radiometric analy-

sis to determine their age. Her calculations are based on findings that clams add one band a year to their shells; the bands vary in size from year to year, with the widest frequently occurring every 22 years—coinciding, Thompson believes, with the earth’s double sunspot cycle. “The clamshell bands are quite similar to tree rings,” Thompson explains. “They’re really a way to read history. When we know more, I think we’ll be able to read the quahog’s bands.”

Another significant oceanic chronology is now being recorded by a mollusk of even humbler origin than the clam. The lowly mussel has emerged as the world’s most efficient pollution-recording device. “For oceanic research, it’s the best monitoring system we have,” says Dr. Eric Schneider of the United States Environmental Research Laboratory in Narragansett, Rhode Island. “What the little buggers do,” he says, referring to his favorite bivalve, “is pump from 1 xk quarts to two quarts of water through their body every hour and sift out the food through their gills. But, at the same time, they concentrate the pollution in the water in their bodies at levels which we can measure.” The mussels can detect such varied contaminants as petrochemicals, heavy metals, synthetic compounds like DDT and PCB, and even signal the presence of radioactivity.

Mussel Watch—a global pollution network based on analysis of mussel contaminants—was set up by 20 nations late last year. In the U.S., sampling is done annually on the Atlantic, Pacific, and Gulf coasts.

In Canada, Professor Daniel Cossa of the Université du Québec in Rimouski has used the ubiquitous bivalve to study pollution in the St. Lawrence River. Not all Canadians, however, are completely I sold on Mussel Watch.“I think it can be £ overrated,” says Dr. Jack Uthe of o Fisheries and Oceans Canada. “Mussels s are good to identify contaminants but ^ to go in and test every year and measure í pollution levels doesn’t seem to me to be the answer. Once you identify the presence of pollutants, the idea is to treat the whole ecological environment to get rid of them. I just don’t think monitoring is the whole answer.”

Despite the breakthroughs that have elevated the mussel and the clam to new scientific heights, a pressing gastronomic problem still remains: can you eat for dinner what you just sliced up in the laboratory? Informed opinion differs. “Oh, I eat mussels,” says Schneider, “but I always want to know where they come from first.” But for Ida Thompson, clambakes are a thing of the past. Confesses the Princeton scientist: “I haven’t been able to eat a clam for

five years.”

Rita Christopher