LSU scientist finds new species of clam
The bags of rabbit food, without a four-legged creature in sight, raised some eyebrows and prompted some jokes during a 2003 deep water cruise for Robert Carney, professor of oceanography and coastal studies at LSU.
The jokes don’t matter anymore because those bags of compressed alfalfa pellets led to the discovery of a new deepwater clam species.
The discovery, published recently in Scientia Marina, was years in the making with a team working to identify and classify the clam that Carney didn’t mean to find at all. He was looking for tubeworms.
It all started with the 1992 salvage of a ship off the coast of Spain that had sunk in the 1970s carrying vegetable matter in the form of sisal, sunflower seeds and beans.
The discovery of organisms on the ship normally only found around cold seeps containing hydrogen sulfide gave Carney the inspiration to try to create artificial cold seeps in an attempt to attract tubeworms for study.
The tubeworm is one of many organisms that live on these cold seeps in the ocean, so named not because of their temperature but just to differentiate them from thermal vent communities that thrive on superheated water in the ocean.
The cold seeps produce hydrogen sulfide, which becomes food for bacteria that live within other organisms, such asclams and tubeworms.
Those bacteria in turn provide things the larger organism needs and they live happily in a symbiotic relationship down on the ocean floor.
The idea was to create an artificial hydrogen sulfide environment in hopes of attracting these types of organisms, but hydrogen sulfide is an extremely dangerous gas and can be volatile to handle.
In contrast, rabbit food is cheap and easy to handle and since vegetable matter creates hydrogen sulfide when it decomposes in salt water, Carney came up with the idea of putting rabbit food into a bucket. That material was covered with oyster shell, then sent to the ocean floor in hopes that the hydrogen sulfide production would attract cold seep organisms.
In 2003, a number of these compressed alfalfa rabbit food-filled buckets were put out in a number of places, including the Gulf of Mexico to see what a few years would bring.
The next step was to wait.
Carney said he had hoped to be able to leave the buckets down for about five years, but when an opportunity came up three years later with access to a submersible, he had to take it.
What they found was very few of the tubeworms he was hoping to attract living on the fake cold seeps, but there were about 30 little clams.
A couple of years later, Carney was giving a talk about his work and was approached by another researcher who was interested in using the clams he had found in her research.
Clara Rodrigues, of the Campus Universitario de Santiago in Portugal, worked up the DNA in a lab in Paris with results going to P. Graham Oliver, of the National Museum of Wales, who declared the species as new.
The tubeworms weren’t a total loss though.
In 2009, six years after the buckets were put into the water, Carney said he was invited on a research cruise which gave him a chance to look at a few of the remaining buckets that were on the sea floor. They were full of tubeworms he had been trying to attract all along.
He is working now to make proposals for funding to go out and pick them up for future study.
“As far as I’m concerned, the Gulf of Mexico is the most interesting deep sea there is,” he said.