On Location Aboard Alvin: Second DispatchFriday, May 14Today's picture credit is BLee
Williams/WHOI (BLee is one of the Alvin pilots and yes, his name really is
spelled/capitalized BLee) The red-tipped organisms are Riftia pachyptila, or tubeworms.
More on that below. The grey-tipped probe stuck into the bunch of Riftia is
the electrode array that I talked
If any animal would be called the poster child of deep-sea hydrothermal
vents it would be the tubeworms. Where we are on the East Pacific Rise
there are three types of tubeworms: Riftia, Tevnia and Oasisia. Riftia
extend up to 2 meters up from the sea floor. The white tube they secrete
gives them enough structure to hold themselves up. Extending from the top
of the tube are the red gills that serve as their "respiratory center"
Oxygen and sulfide diffuse into tubeworm here and are transported down to
the trophosome. Tubeworms do not have a gut, instead bacteria are housed
in the trophosome.
The bacteria at deep-sea hydrothermal vents are different from organisms
in the surface waters of the ocean and from land plants primarily because
they rely on a different type of energy. Green plants that you see around
you and algae that you see in the water all rely on sunlight for energy.
They use sunlight to convert carbon dioxide to organic carbon, hence they
are called "primary producers". Bacteria at hydrothermal vents and in some
other specific niches on the surface use chemical energy in lieu of
sunlight to convert carbon dioxide to organic carbon. Why? Because 2500
meters under the surface there is absolutely no sunlight that can
penetrate that far through the water.
So the bacteria in the tubeworms are using the sulfide as chemical energy
to convert carbon dioxide to organic carbon. However the bacteria in the
tubeworms are not the only ones capable of this conversion-those in the
clams, mussels and some of the free-living bacteria are also able to use
the sulfide as a chemical energy source.
Tomorrow I will dive with Anna-Louise Reysenbach, my advisor in Oregon.
Krista
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about yesterday. In the foreground of the picture is the end of the basket
that is attached to Alvin with other pieces of science gear waiting to be
used during the dive.
