TODAY'S WEATHER
Cloudy
64°F
(17.8°C)
Latitude: 27deg 0’ N
Longitude: 111deg 24’ W
Wind Direction: WNW
Wind Speed: 19 Knots
Sea State: 3
Swell(s) Height: 3 Feet
Sea Temperature: 64°F (17.8°C)
Barometric Pressure: 1014.8 MB
Visibility: 20 Nautical Miles
BREAKFAST
Oatmeal
Eggs to order
Corned beef puff pastries
Ham
Cottage potatoes
Pancakes with mixed berries
Fresh fruit
LUNCH
“Fishmonger” clam chowder Sloppy Joes
Tuna sandwiches
Bombay rice salad
Onion rings
Salad bar
DINNER
Grilled lamb chops
Jurel fresco al moho de ajo (Garlic style fresh yellowtail)
Roast Yukon gold potatoes
Pesto cous cous
Cauliflower florets
Green beans with sautéed peppers
Roast garlic
Herb foccacia bread
Oh Yeah! Bars
Don Nuzzio watches as the electrodes are lowered into the core
to take chemical measurements.
Daily Update: Dive
3522
January
19, 2000
By Dr. Dan Fornari and Dr. Susan Humphris
The wind picked up overnight, but
the morning dawned with another beautiful Baja sunrise. Craig Cary,
Liz McCliment, and Pilot Steve Faluotico spent a full day on the
seafloor taking sediment cores, collecting clams, and doing more
chemical sensor and "Sipper" work at the hydrothermal vents.
Today marks the start of the second week at sea, which means it's
time for another Fire & Boat Drill to practice emergency procedures.
At 1015 hrs, the alarm sounded and the crew simulated a fire in
the motor propulsion room. All of the scientists mustered in the
main lab and waited for the crew to finish their drill.
Today’s work focused on the core samples. The scientists
are trying to learn how the chemical environment within the thick
seafloor sediments affects the community of microorganisms that
live there. These microorganisms form colorful white, red, yellow
and brown mats on the seafloor.
A key piece of equipment we are using is the Electrochemical Analyzer.
This instrument is the brainchild of Don Nuzzio, the president
of Analytical Instrument Systems, Inc. in Flemington, N.J. Don’s
company makes sophisticated chemical analyzers that scientists
use to monitor coastal waters, lakes, rivers, and now hydrothermal
vents at the bottom of the ocean. The Electrochemical Analyzer has tiny chemical
sensors (or electrodes) that measure oxygen, iron, sulfur and manganese concentrations
at different locations around the vents. The presence of these elements determines
which microorganisms live in specific places.
Before coring, the scientists in Alvin must choose a suitable site. First
they search for bacterial mats on the ocean floor. Next they use the Electrochemical
Analyzer to measure the chemical environment in the water directly above the
mat. If they decide it is a good place to core, they stick a temperature probe
into the sediment to check whether the sediment temperature is less than 100°C.
Microbes are most likely to be found at these cooler temperatures. Next, they
use the “Sipper” to collect water samples, which they will analyze
later in the ship’s lab. Finally, they are ready to take a 30-centimeter
core sample. They plunge the corer through the bacterial mat and into the sediment
below. (Check out the video of coring the seafloor).
Once the cores are back on the ship, the scientists make numerous electrochemical
measurements along the top five centimeters of each core. This is the part of
the core that is the most critical to the microorganisms. They then slice the
core into sections, trying to separate parts of the core that have different
chemistries. For example, they might have one slice that contains oxygen and
another slice that contains hydrogen sulfide. Before slicing, they put the core
inside a bag filled with nitrogen. This prevents the chemical environment inside
the core from changing due to air exposure.
The scientists then put the slices into a centrifuge. The centrifuge spins the
slices at very high speeds, drawing the water out of the sediment. The microbiologists
take some of the sediment to grow (or culture) any of the microbes that are present.
They then use molecular techniques to determine which microbes are present. The
rest of the sediment is taken back to the shore lab where scientists will identify
the minerals present and look for hydrocarbons (petroleum products). Hydrocarbons
are abundant in Guaymas Basin sediments. Scientists will also analyze the water
that was spun off in the centrifuge for iron and sulfur compounds.
After all of the analysis is done, the scientists will couple the chemical environment
data with the results of the microbiological work. They hope to learn how the
chemical environment affects the types of microorganisms that survive on the
ocean floor.
Dive Summary
On Bottom: 0922 hrs.
Off Bottom: 1532 hrs.
Maximum Depth: 2000m
The dive started at Rebecca’s Roost-a large sulfide structure with many
ledges (or flanges). The scientists on Alvin collected “Sipper” samples
and did chemical scanner profiles on the hot hydrothermal fluids discharging
from the vent. Growing out of the top of one of the flanges was a small 300°C “beehive” chimney.
It is called a "beehive" because it has delicate surface textures that resemble
a paper wasp's nest. Steve used Alvin's manipulator to sample the “beehive” (check
out the video of the “beehive” sampling). The sample broke off, but
Steve was able to grab it with the manipulator and put it in the basket. He also
collected some fluids with the gas-tight sampler.
Craig, Liz, and Steve then headed away from the area of the most active venting.
They wanted to find and sample sediment that differed from the sediment they
had been sampling over the past few days. They collected another pink spiny spider
crab and four cores of mud. The mud was much different from the gas-rich sediment
that they had sampled near the vents. George and the rest of the chemistry group
are now analyzing the cores.
Craig, Liz and Steve also collected more clams. All in all, another successful
dive.
One additional note -- Craig and Tim learned that the spiny spider crab, while
fairly common in the deep ocean, has never been sampled and cataloged before.
They have agreed to send the one they collected on this dive to the Smithsonian
Institution in Washington, D.C, to be archived.
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