BOWLS Cruise Blog

Day 8
June 29, 2014

Osedax worm

It is great to be back on the R/V Oceanus. I had the pleasure of being a part of the trip fourteen months ago that deployed the landers that we're picking up on this cruise. Back then I had never seen a live Osedax specimen, only their DNA sequences which I was working on. Due to the specialized nature and rarity of the habitat of Osedax, I worked on them for a year and a half before I ever saw one alive --- in Antarctica! Here I have gotten to see even more live, and large, Osedax.

Osedax is one of the two main focuses of the Bone and Wood Landers project. Osedax are highly specialized members of Siboglinidae (within the segmented annelids worms like earthworms), whose members include giant tubeworms found on hydrothermal vents and hydrocarbon seeps. Most members of Siboglinidae absorb inorganic chemicals from the environment, like hydrogen sulfide or methane, and transport these chemicals to bacteria that live inside them. The bacteria then break these chemicals down and use them to create nutrients for the worm. The worm gets food and the bacteria get a safe place to live.

Tube worms from a hydrocarbon seep

However, Osedax are a special case. They have adapted to colonize whalebones, where their live-in bacteria can break down the fats within the bones. This is scientifically interesting because in all members of siboglinidae the symbiotic relationship between bacteria and worm is obligate for the worm, that is, the worm cannot survive without the bacteria. Therefore something fascinating happened for this adaptation in Osedax, from one symbiont to the other, to have occurred.

Since whalebones aren't easy to find on the bottom of the ocean, it's hard to sample Osedax. Luckily, using this project's landers allows for a way to efficiently capture this cool organism. No matter what you're working on, it's nice to be able to see it with your own eyes.

Damien Waits

Graduate Student

Auburn University

Last updated: 06/30/2014