12/1/2009: A Motley Collection of Boneworms
MOSS LANDING, CA - It sounds like a classic horror story: eyeless, mouthless worms lurk in the dark, settling onto dead animals and sending out green "roots" to devour their bones. In fact, such worms do exist in the deep sea. They were first discovered in 2002 by researchers at the Monterey Bay Aquarium Research Institute (MBARI), who were using a robot submarine to explore Monterey Canyon. But that wasn't the end of the story. After "planting" several dead whales on the seafloor, a team of biologists recently announced that as many as 15 different species of boneworms may live in Monterey Bay alone.
After years of study, the researchers have begun to piece together the bizarre story of the boneworms, all of which are in the genus Osedax. The worms start out as microscopic larvae, drifting through the darkness of the deep sea. At some point they encounter a large dead animal on the seafloor. It may be a whale, an elephant seal, or even the carcass of cow that washed out to sea during a storm. Following chemical cues, the tiny larvae settle down onto the bones of the dead animal.
Once settled, the boneworms grow quickly, like weeds after a rain. One end of each worm develops feathery palps, which extract oxygen from seawater. The other end of the worm develops root-like appendages that grow down into the bone. Bacteria within these roots are believed to digest proteins and perhaps lipids within the bones, providing nutrition for the worms.
Soon the worms become sexually mature. Strangely enough, they all become females. Additional microscopic larvae continue to settle in the area. Some of these larvae land on the palps of the female worms. These develop into male worms. But they never grow large enough to be seen by the naked eye. Somehow these microscopic male worms find their way into the tube that surrounds the female's body. Dozens of them share this space, not eating at all, but releasing sperm that fertilize the female's eggs.
Eventually the female worm sends thousands of fertilized eggs out into the surrounding water, and the cycle begins again. Dr. Robert Vrijenhoek, an evolutionary biologist at MBARI, has been fascinated with these worms ever since he and his colleagues first discovered their unusual life styles and bizarre reproductive habits. Vrijenhoek has been trying to find out how widespread and genetically diverse these worms are. He would also like to know how they manage to find and colonize the bones of dead whales in the vast, pitch-black expanse of the deep seafloor.
Between 2004 and 2008, Vrijenhoek's research team towed five dead whales off of Monterey Bay beaches and sank them at different depths within Monterey Canyon. Every few months, coauthor Shannon Johnson and others on the team would send one of MBARI's remotely operated vehicles (ROVs) down to study the worms and other animals that had colonized the whale carcasses.
To their surprise, the different whale carcasses yielded different types of boneworms. One whale carcass hosted three or four different types of worms. After examining all of the worms, coauthor Greg Rouse concluded that most of them were entirely new to science. The researchers also discovered that the worms would colonize cow-bones placed on the seafloor, which showed that the worms were are not limited to feeding on dead whales.
In their recent paper in the journal BMC Biology, Vrijenhoek and his coauthors describe the results of extensive DNA analyses on all the different types of Osedax worms that have been discovered so far (including two species found off Sweden and Japan). This work suggests that these worms could belong to as many as 17 different species, most of which have yet to be named. None of the worms appear to interbreed, despite the fact that some of them grow side by side.
Based on their appearance and similarities in their DNA, the researchers divided the boneworms into several groups. Some of the worms have feathery palps, which may be red, pink, striped, or even greenish in color. Others have bare palps. One type of boneworm has no palps at all. Its body forms a single, long, tapering tube, which curls at the end like a pig's tail. This worm has evolved to live in the seafloor sediment near a dead whale. It sends long, fibrous "roots" into the mud, presumably in search of fragments of bone on which to feed.
Knowing how fast the DNA of these worms changes (mutates) over time, the researchers can calculate how long it has been since worms in the genus Osedax first evolved as a distinct group. Using one possible estimate of mutation rates, the researchers hypothesized that this group could have evolved about 45 million years ago-about the time the first large open-ocean whales show up in the fossil record. Alternatively, the worms may have evolved more slowly, which would suggest that the genus is much older, and first evolved about 130 million years ago. If this second estimate is correct, the worms could have feasted on the bones of immense sea-going reptiles during the age of the dinosaurs.
Eventually the researchers will give all these new worms their own species names. First, however, they must collect enough samples of each possible species for additional laboratory analysis and distribution to type-specimen collections. Like a classic horror story, the macabre saga of the boneworms will continue to thrill marine biologists for years to come.
This research sponsored by the David and Lucile Packard Foundation.
6/4/2004:
GOVERNOR CALLS FOR ACTION ON COASTAL AND OCEAN PROTECTION
In an April 2004 update entitled "Articles of Faith," I wrote about people who do the right thing regardless of whether anyone takes notice or whether they can ever finish the task. I described how we are sometimes faced with large amounts of trash on the water and how we do our best to scoop it up--especially the balloons, shopping bags and garbage bags that can be ingested by marine life, leading to death in many cases.
We know of so many people whose beach walks are spent picking up trash, who ardently conserve water and who give serious thought to the ramifications of how we live now on the world tomorrow. They are automatic members in this select club that has no rules except one: Keep doing what they're doing.
Here is a response to that update:
5/19/2004: Hi Heidi ~
I just got back from an Earthwatch Trip to Matura Beach in Trinidad where I worked with Nature Seekers to pit and flipper tag Leatherback sea turtles. I was really sorry to see all the trash that littered the land, beaches and waters of Trinidad. It would probably be more accurate to say I was DEPRESSED to see all the trash!
Anyway, after being away for a month I returned home to lots of emails, not the least of which were your wonderful newsletters. I just read the one about the plastic bags floating on the surface of the bay. You probably already know that Leatherback sea turtles feed almost exclusively on jelly fish. To a hungry Leatherback sea turtle, a plastic bag floating in the water can look just like a jelly fish. Too many times they consume plastic this way and die a horrible death.
I find it very hard to believe that people don't understand this when they thoughtlessly throw their trash away inappropriately. I would like to apply for your Drop in the Bucket Brigade. While in Trinidad, each night as I patrolled Matura beach, I would collect as much trash as I could carry in the hopes that the turtles would not encounter it in their nightly landings on the beach to lay their eggs. It takes very little trash to return a Mom Leatherback to the sea rather than to stay and deposit her eggs in a nest.
The Nature Seekers are doing a WONDERFUL job of trying to protect their beaches from poachers and others just on the beach to harass the Leatherbacks. Even after their annual beach cleanup before the nesting season starts leaves the beach completely clean, the nightly tides litter the nesting areas again.
Sadly to say, the oceans around the world share in this same problem. As a "visitor" to Trinidad, I didn't feel I could approach anyone I saw throwing trash by the side of the road. Even a car on it's way to the beach to "visit" the turtles was observed throwing trash out their car window. They were spoken to by the security force but because I was just a visitor to their island, I didn't feel it was appropriate for me to say anything to the woman I saw at a bus stop throw her empty beer bottle over her shoulder into an empty field.
As a concerned citizen of this world I will always feel compelled to do what I can to not litter and pick up after those who do. I don't have any other answers except to tell the elementary school children I talk to about my "turtle experiences" that if they do NOTHING else to help the cause, they can at least recycle and dispose of their trash appropriately.
Sorry for going on and on like this but your newsletter hit a nerve! Keep up the good work with your fight for the environment.
Best wishes, Diane Barber
[We do know what leatherbacks feed on and we see them here in the summer, which is one more reason to keep plastic out of the water. I think talking with litterers is an important step, though. Whose world is it, anyway? Diane is a shoo-in for "The Drop in the Bucket Brigade." How about you?]
7/8/2003: The Management Plan Revision for the Monterey Bay National Marine Sanctuary Nears Completion
In meetings that spanned two very full days, the Sanctuary Advisory Council was given excellent presentations by Sanctuary staff on everything from personal watercraft to Davidson seamount to invasive species to the effects of cruise ships in our waters. You can read all about the issues and the upcoming final meetings in Santa Cruz by going to the Sanctuary's web site:
Monterey Bay National Marine Sanctuary Management Plan Review
11/27/2002: We just won one in the fight to stop Low Frequency Active Sonar (LFA) deployment in the world's oceans because it can be lethal to whales and dolphins. Now we find there is a plan afoot to deploy sonar on the coast of Central California, targeting the California gray whales on their southbound migration. If you think this is lunacy, we agree. Want to help fight for the whales? READ MORE then Write NOW to the California Coastal Commission and tell them your thoughts. The address is below.
Executive Director of the California Coast Commission, Peter M. Douglas
45 Fremont, Suite 2000
San Francisco. CA 94105-2219
11/2/2002: We've won some BIG ones! This week, The Navy was stopped in its attempt to comb the world's oceans with high-powered Low Frequency Active Sonar (LFA) because it could cause irreparable harm to whales and other sea life.
Also, the National Science Foundation was ordered by a Federal Judge to stop sounding underwater blasts in the Sea of Cortez because it's harmful to whales.
See What You Can Do below for more on the campaigns we (and many of you) joined to stop these projects.
