of Study: Guaymas
target area for the second day of exploration in the Guaymas Basin was a
site located in the Southern Trough at about 2,000 meters of depth. This
site represents one of the most complex edifices recognized so far in the
Guaymas Basin; it also harbors a variety of different sulfide deposits,
which acquire pagoda-like shapes that may grow up to 15 meters in height.
One can also distinguish other deposits similar to rounded mounds packed
on their surface with thick clumps of vestimentiferan worms of the genus Riftia.
Nearby there are tall chimney-like deposits, built up by the progressive
deposition of sulfide materials; hydrothermal fluid can be seen flowing
out of the top of such deposits.
this site, commonly referred to by previous researchers as Rebecca's
Roost, constitutes an exuberant vent system dominated by the luxurious
development of dense colonies of Riftia pachyptila. At left is a
photo of a Riftia individual in the lab. Joe
Jones is holding the tube and Shana
Goffredi is holding the animal from that tube. The external surface of
the worm tubes provide an important substrate for the settlement of a
complex fauna of epibionts, which graze the bacteria growing on the
surface of the tube worms. This is the case of numerous scales worms (Polynoids),
whose dark or pink coloration adds another attraction to the untrained
observer. The so-called palm worms (Alvinellid worms) can also be seen
attached to the external tube surface of Riftia, extending their
bright brownish tentacles out of their own small tubes (see below).
the notorious advance of unmanned remote controlled underwater vehicles
has greatly facilitated our capacity to explore and study the hydrothermal
phenomena. In the case of the Guaymas Basin, located in theCentral Gulf of
California, there are a number of important features that make the area
unique in comparison with some other known systems in the Pacific. The
presence of gas and thermogenically produced oil and the precipitation of
sulfide compounds, create a habitat heterogeneity clearly observed in the
composition of the communities studied. During dive T-549 conducted today,
we had the opportunity to sample the most contrasting habitats: from the
solid deposits occupied by massive Riftia colonies, to the
desolated plain bottoms whose only signs of life appear concentrated
around white or yellowish mats of chemosynthetic bacteria (see above).
is evidently more biodiversity on the hard substrates than on the regular
soft sediments. However, in both cases, the morpho-physiological
adaptations exhibited by their inhabitants are equally fascinated. To test
this idea, it is only necessary to obtain a temperature profile of the
surrounding environment (water and sediment), to quickly realize the
enormous stress that these organisms are exposed to. Inside bacterial
patches, the temperature may reach up to 169º C, sufficient to break down
the molecular structure of common marine individuals.
question still remain unanswered in relation to the complex processes that
make possible the existence of life in the deep hydrothermal vents. The
unraveling of these mysterious forms of life represents a true challenge
for modern science.