Daily Update: Symbiosis: You scratch my back, I'll scratch yours
April 13, 2001
By Amy Nevala

Bacteria may be the most under-appreciated organisms on this planet, with humans spending a better part of their lives trying to soap, scrub and spray them away.

But at hydrothermal vents, they are the basis of all life.

“People only think of bacteria as germs,” said microbial biologist Colleen Cavanaugh, “yet bacteria at hydrothermal vents are the reason larger animals exist in these environments, many in symbiotic associations.”

Symbiosis is a relationship in which both organisms benefit. Each partner provides the other food or shelter. In some cases, it is both of these things.

In her research at Harvard University, Colleen is finding that bacteria and most of the bigger vent animals coexist using symbiosis. This is true for shrimp, mussels and snails that she has studied at hydrothermal vents in the Pacific and Atlantic Oceans.

She has found the same relationships here in the Indian Ocean.

In the video-data collected several days ago at hydrothermal vents using ROV Jason, we saw a good example of symbiosis between shrimp and bacteria. The wiggly vent shrimp munch the bacteria that live on their bodies. To keep up this bacteria supply, the shrimp swarm the hydrothermal vents that pump out hot chemicals used as energy by the bacteria.

Colleen’s work and that of the other scientists continues here, despite a third day of 15 foot waves. While ROV Jason’s duties are postponed until the seas subside, geologists were able to dredge volcanic rocks from the rift valley walls of the Central Indian Ridge.

“When we do find the hydrothermal vents in this area, we need to know what sort of rock they are built on,” said Geologist Susan Humphris, who together with Geologist Dan Fornari and crew members pulled up a heavy load of the sooty, black pillow lava, named for its rather bulbous appearance

Inside the main lab, Chemists Bob Collier, Marvin Lilley and others on the “Plume Hunting Team” continued their non-stop efforts to find the elusive hydrothermal plume here at 24°S.

“So far it’s Plume 1 and Scientists 0,” said Dan. After several meetings today about the CTD data and bathymetric maps, we have more sites to investigate tonight.

“Science is all about not giving up,” said Dan. Even if today is Friday the 13th.

[Back to top]