Posted by graduate student Alison
Sipe, University of Delaware College of Marine Studies.
Marine geologist Dr.
Dan Fornari has completed his contour bathymetry maps
of the Guaymas Basin. This is the first time that the basin
depth has been mapped using a multi-beam system. The SeaBeam
multi-beam sonar system detects features on the seafloor
that are greater than the size of a football field and are
taller than about 10 15 meters. This means that a
small vent chimney would go undetected, but more expansive
seamounts would be detected. Dan has been running the SeaBeam
at night because during the day when Alvin is diving,
the ship must remain stationary at the dive site. Each night,
the ship makes 40-mile-long transects across the Sea of
Cortés, each track 2 1/2 miles from the next. The
total area covered is 60-by-40 miles, or 2,400 square miles.
two most prominent features of the Guaymas Basin are the
northern and southern troughs, which are the seafloor spreading
axes of the Sea of Cortés. Dan and his group will
analyze the data further when he returns to Woods Hole Oceanographic
Institution. He will create two-dimensional contour maps
as well as three-dimensional perspectives of the basin.
Dan Fornari has constructed bathymetric maps of many other
ocean basins as well, but this map will be a wonderful contribution
to hydrothermal vent researchers.
I walked down the hall past the darkroom where the microscope
is located, I could hear squeals coming from inside. I found
Reysenbach and her graduate student Krista
Longnecker taking turns peering through the microscope.
Drs. Reysenbach and Cary have been trying to learn what
types of hyperthermophilic (hyper=super, thermo=hot, philic=loving)
bacteria live in the vent chimneys. Their culturing, or
growing, experiments have led to unique findings. I gazed
through the microscope lenses to see a continuous line of
filamentous bacterial cells connected like a freight train.
What is unique about this bacterium is that it is sheathed
its like the microbes are wearing a little
coat. Although Anna-Louise is an expert researcher of hyperthermophilic
bacteria, this is the first time she has seen sheathed bacteria
growing at 70° C (thats pretty toasty!).
Boone, and Krista Longnecker have all been growing methanogens
(methane-producing bacteria) that they have collected from
the vent chimney and sediment cores. In addition to methanogens,
graduate student Melissa
Kendall has succeeded in her attempts to culture iron-reducing
bacteria. These bugs produce magnetite, or iron filings,
as they grow. The
scientists hold a magnet up to the test tube culture of
the bacteria and the iron filings drift to the side of the
tube touching the magnet. The microbiologists on board are
undoubtedly growing bacteria that no one else has ever seen.
The microbial world is not well investigated only
1% of the Earths bacteria have been described. The
microbiologists have a lot of work ahead of them.
Tonight, we witnessed a remarkable celestial event. I feel
honored to have seen not only a spectacular sunset over
the Baja peninsula and a gray whale spy-hopping in the distance,
but at the same time a full moon rise over the flat ocean.
I couldnt decide where I should stand on the ship
to see both, but found that the ships bow provided
a prime view. Even more, a full eclipse of the moon occurred.
We watched the sky grow darker as the Earths shadow
slowly crept across the moon; the moon turned into a mustard-yellow
glowing ball. With the sky so dark, the stars appeared in
the trillions. What better place to witness such an event.
At one point, someone heard a flap in the water. Thirty
feet below us at the tip of the bow where the ships
hull cuts through the sea were six dolphins playfully racing
the boat. They swam at incredible speeds, weaving in and
out of each other. Some took a break for a few minutes and
then returned to play with the group. We heard their grunts
as they blew air threw their blowholes. With our hands curled
around the ships hull, we gazed until the last two
turned away from their fun, either through exhaustion, boredom,
or who knows what. It was a breath-taking show.
If we stared at the sky long enough, each of us began to
spot shooting stars. It was then interesting to watch the
Earths shadow creep away from the moon following the
1 1/2-hour total eclipse. The sky brightened, and the trillions
of stars we were privileged enough to see slowly disappeared
against the lightened sky. A frigate bird perched on the
antenna above seemed to enjoy the display equally as well.