Mail Buoy
April 9, 2001
I teach an online oceanography course at Fullerton Community College in Fullerton, CA (about 10 minutes from the second happiest place on Earth -- your expedition being the first!) My class is following your expedition and enjoying it immensely.
What is the current thinking on the evolution of vent organisms, such as the tubeworms, shrimp and mussels? Did they derive from rocky intertidal species (i.e. shallow water species) or vice versa?
W. Sean Chamberlin, PhD,
Assistant Professor
Hi Sean:
That’s a really interesting question that many vent scientists are working hard to answer. We have some evidence that chemosynthetic habitats at hydrocarbon cold seeps (from ~500 to 1700m) bordering the Gulf of Mexico and the US west coast may have served as refugia for lineages of vent species when venting may have not been prolific on mid-ocean ridges (for example, during mass extinction events in the deep sea). We have some evidence (based on DNA comparisons of present day animals) that this may have happened with mussels and shrimp inhabiting the Mid-Atlantic Ridge and in the Gulf of Mexico. As for tubeworms, it appears that there may have been multiple colonizations from shallow seep habitats to deep-vent habitats and vice versa. One scientist on board is examining the DNA from the abundant shrimp found on the Mid-Atlantic Ridge and here on the Central Indian Ridge as well as those from intertidal habitats to address this very question.
Stay tuned and learn more about the massive shrimp swarms we are finding/discovering here....
Thank you for your question.
Tim Shank
What is slurping? And what is syntactic foam? We are enjoying following the cruise. Thanks for making it so easily available.
Wakefield High School Oceanography Classes
Wakefield MA
Hello there:
Good questions! I had Will Sellers of the Deep Submergence Operations Group provide some more details on the second one.
What is slurping?
Slurping is the very non-scientific term for one of the ways that we collect organisms. We use a long plastic tube with a metal tip attached to a pump that sucks up water and organisms into a container. You can think of it as an underwater vacuum cleaner. It is a great way to collect shrimp swarming around the vents!
And what is syntactic foam?
Syntactic foam is a special material made of tiny glass spheres (filled with air) stuck together with epoxy. It is used to provide flotation under conditions, such as at the bottom of the ocean, where there is a lot of pressure. That is why we use it to make vent markers and on Jason. There are different types of syntactic foam. On Jason, we use 32 lb foam. Since 1 cubic foot of seawater weights 64 lbs, we get 32 lbs buoyancy out of 1 cubic foot of syntactic foam. Jason has 35 cubic feet of syntactic foam -- so you can calculate how much buoyancy it provides. Syntactic foam is also very expensive -- $1000 per cubic foot -- and is very hazardous to work with. It has to be handled in a lab with special safety equipment because of the ground up glass dust that is produced when it is cut.
Hope this answers your questions -- and you will keep Diving and Discovering!
Susan Humphris
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