March 19, 2000

Ten-Foot Worms Live in Hot Water

You and two companions are squeezed into a six-foot titanium bubble slowly descending into the inky black depths of the Pacific ocean. You pull a blanket tighter around your shoulders to ward off a bone-aching chill.

Then the temperature starts to rise - as does your excitement. You are approaching a "hydro-thermal vent" long theorized to exist at the mid-ocean seams where lava from Earth's core spread the sea floor.  

The blanket becomes uncomfortably warm, and you remove it. At 625 degrees Fahrenheit you drop a little ballast to level off a few feet above the sea floor. You turn on your search light and peer through a small foot-thick Plexiglas porthole. You worry a little that the heat will soften the Plexiglas.

There, where the water pressure is 4,000 pounds per square inch, is a community of creatures never before seen -- blind shrimp, pink fish hanging head down in tall chimneys that belch black smoke, football-size clams and ten-foot red-tipped worms waving like a field of poppies.

How could living creatures thrive in such an environment -- where no sunlight ever penetrates, and the water would boil fiercely if not held back by unbelievable pressure?

 * * *

This was the situation as told by Donald LeBlanc of Punta Gorda. He now is retired but formerly was instrument shop supervisor at the Woods Hole Oceanographic Institution of Massachusetts.

Oceanographic is comprised of entrepreneurial scientists supporting their work through donations, grants and contract services.

The deep-diving sub described above was constructed in 1973 and certified for dives of 16,000 feet - three miles. It was named Alvin for its designer Allyn Vine a Woods Hole scientist.

Alvin's original, steel sphere of 1964 was sanctioned for dives of 7,500 feet. It's most famous exploit was that of 1966 which located a hydrogen bomb lost in a U.S. B-52 bomber crash off the Spanish Coast.

 Don and his crew built scientific equipment for both submersibles. This included cameras, lights, mechanical arms and various sensors.

The mother ship for Alvin is a research vessel named Atlantis. It was constructed in 1962 through a grant by the National Science Foundation. The pair has conducted thousands of deep-sea dives in pursuit of marine and environmental knowledge.

* * *

The discovery of hydro-thermal vents occurred in 1977 near the Galapagos Islands. Among the strange creatures living there around "black smokers" were giant worms and a six-sided creature thought to have become extinct 40 million years ago.

Scientists were astounded. It had long been known that lava from the Earth's core was welling up in mid-oceans and pushing the sea floor under continents. It had not been anticipated that replicating life forms thrived in such a hostile environment.

 From whence came the food to live and the energy to procreate?

Water (composed of hydrogen and oxygen) percolates in the fissures and converts lava sulfur to hydrogen sulfide - a corrosive, black chemical we air-breathers relate to rotten eggs.

In our familiar world, sunshine provides the energy. It activates green cells of plants to combine carbon-dioxide and water into carbohydrates (starch sugar) - fuel for all living things heretofore known by us.

This creation of food by green plants and sunshine is a process we call photo-synthesis (light- putting together). In the Stygian dark of the deep sea, whence comes the energy to create food necessary for life?

Woods Hole scientists analyzed samples of water near the vents and marine creatures captured by Don's mechanical devices. They confirmed that bacteria are the foundation of life in the deepest deeps.  

Those microscopic organisms use the chemical energy in hydrogen-sulfide to create carbohydrate for itself and all other creatures in the thermal-vent food chain. Now this process is called chemo-synthesis.

It is surmised that life on earth began with such one-celled bacteria - not really alive, but not really inert - struggling to reproduce (why and how?) in a soup of elemental chemicals and excessive heat. Today's thermal-vent bacteria clump together like flakes of snow.

This mystery of life is pursued by biologists, chemists, archeologists, geologists and astronomers. Woods Hole scientists continue to search for answers in the sea.

They have determined that the giant worms around thermal vents have no mouth, digestive system, heart or brain. The worm secretes a substance that hardens into a leathery tube in which they live. Bacteria migrate to the body of the worm within its tube.

The worm extends a lung-like organ from the tube with which it concentrates sulfide and delivers it to the bacteria. In return, the bacteria convert sulfide and carbon dioxide into carbohydrate which nourishes itself and the worm.  

Scientists call this mutuality of dissimilar organisms "symbiosis" (living together). A common example in Florida is the partnership of live-oak trees and Spanish moss.

 Interestingly, Woods Hole scientists have discovered a small thermal vent colony in the relatively shallow Gulf of Mexico 30 miles west of Tampa Bay. This even though sunlight penetrates to the sea floor sufficiently to sustain green plants and algae which are more efficient producers of starch sugar.  

Artesian springs flowing from the edge of Florida's continental shelf carry enough hydrogen-sulfide to sustain the vent community. This is a condition familiar to Floridians depending upon deep wells for water,  and to Punta Gordans who fill jugs from their famous artesian Fountain of Youth at the corner of Marion Ave. and Taylor St.

Question: how and when did a primitive hydro-thermal vent colony make its way to vent-less Florida?  

Deep ocean tube worms live up to 250 years - a record for creatures without a backbone. They spawn in season, apparently attuned to the solar cycle even though they never experience sunlight. Both eggs and sperm are released in the water to mate and drift. How the fertilized egg obtains its bacteria starter is yet unknown.

* * *

Don is not an academic scientist. However, as a master tool-and-die maker he is the design specialist and craftsman for most Woods Hole  projects. "The scientists tell me what they want to do, then I figure out how to do it," he says.

Among his citations is one by the U.S. Navy for modifying a 13-ton electric-drive clutch for the research vessel Knorr offered to Woods Hole.

Knorr's diesel electric drive system had a tiny vibration that disturbed scientific instruments. To correct the problem, ship builders said the Knorr would have to be put in dry dock and engines removed to mill off a half-thousandth of an inch from the clutch rings. The job would cost millions of dollars which Woods Hole did not have.  

Don said he could mill the clutch rings and drive shafts in place. Because of his can-do reputation, the Navy said go ahead. He wrestled a milling lathe into the bowels of the ship and began working - alone and cramped in close quarters for ten days.

Knorr was delivered for duty without cost and on time. Navy engineers declared the drive train "faultless" and free of all vibration.

The most famous project in which Knorr participated - in cooperation with French scientists -- was locating and photographing the Titanic in 1985.

Don declares his 34-year career with Woods Hole "fascinating." His two sons followed him there.

No wonder they called Don "The man who whistles while he works."

Author: Lindsey Williams

Cutline 1 - two col. Tube worms cluster

Photo by Kathleen Crane, Woods Hole Oceanographic Institution, 1979

[Giant tube worms cluster near the Galapagos Rift, Pacific Ocean  hydro-thermal vent.]

cutline 2 - 2 col. Man at desk.

Photo by Falmouth, Mass.

 [Donald LeBlanc in 1967 builds a scientific instrument for Woods Hole Oceanographic Institution.]