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Deepwater Program: Northern Gulf of Mexico
Continental Slope Habitats and
Benthic Ecology" (DGoMB): This project
is a 4 year multidisciplinary program involving numerous graduate
students. It is investigating the structure and function of communities of
organisms that live near and on the deep-sea floor. Extensive field work
includes bottom photography, coring and trawling, as well as an autonomous
lander used to measure metabolic processes. A new initiative in 2002
includes field work in Mexican waters in collaboration with the National
University of Mexico. More information about this project
visit:
GERG
US
Minerals Management Service |
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Mechanisms Controlling Hypoxia on the
Louisiana Shelf: This study
investigates the mechanisms that underlie the growth of the so-called
"dead zone" in the northern Gulf of Mexico, a region characterized by
hypoxia that has been increasing since the 1990s. In a multidisciplinary
approach, we investigate the impacts of both nitrate inputs and physical
factors determine whether these processes result in a separation of the
hypoxic area into three zones. Our work includes the measurement of oxygen
and nitrate concentrations, benthic respiration rates, sedimentation rates
and the application of physical and biogeochemical models.
More information can be found at:
NOAA's Center for Sponsored Coastal Ocean Research
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Equipment used for
Field Activities |
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The RV/Gyre:
More information about the
RV/Gyre |
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The GOMEX Lander:
A key component of our study was measurement of total sediment community
oxygen demand using the autonomous benthic lander and in situ chambers we
have developed at Texas A&M University. The lander consists of a square
aluminum-pipe frame, which holds 2 in situ incubation chambers, a
multifunction electronic timed release system, a deep-sea multishot camera
and strobe system, ballast weights, and glass flotation balls. The GOMEX
(for Gulf of Mexico) lander free-falls to the sea-floor unattached to any
cable and estimates fluxes of oxygen and metabolites into or out of the
sediments by incubating the bottom water and sediment enclosed in stirred
chambers containing oxygen electrodes. At the end of the deployment,
ballast weights are released by pre-programmed timing device. The lander
then floats back up to surface by positive buoyancy. |
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The GOMEX Lander |
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The Minilander and Benthic Chamber: |
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Our diver-deployed minilander and benthic chamber are used in shallow
water by SCUBA divers in areas such as the Flower Gardens National
Sanctuary, Gulf of Mexico. The in situ flux measurements in shallow water
can be obtained by benthic chamber incubation and the syringe water
samples taken from SCUBA diver. The changes in the chemical concentrations
of oxygen, dissolved inorganic carbon (DIC), ammonium, nitrate, nitrite,
manganese, iron, silicate, and phosphate in the benthic chamber are
used to estimate total community respiration by organisms living with
in the sediments in benthic chamber incubations. |
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◄ Benthic Chamber |
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Benthic Chamber and Mini-Lander |
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The
oxygen concentrations are determined from continuous recording polargraphic oxygen electrodes and
other chemicals are measured in syringe samples taken at time intervals
through out the measurements. At the end of experiment, the instruments
can either be recovered by cable or floated to the surface by the divers'
lift bags. |
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BMICs (Batch Micro-Incubation
Chambers):
In addition to in situ studies, incubations are made of "cores" and
overlying water at near in situ temperature in the shipboard laboratory.
In the "Batch Micro-Incubation Chamber" (BMICs), the change in oxygen and
inorganic nutrients are monitored in the overlying water. Sediment samples
are usually obtained with diver-held Box Cores.
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The Shipboard BMIC chamber |
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The GOMEX Box Corer:
The TAMU-modified version of the Gray-O'Hara modification of the J&O box
corer, referred to as the GOMEX box corer, constructed entirely of
stainless steel, measures 45 x 45 in surface area and penetrates to depths
of up to 50cm. The sediment taken from a Box Corer is used to harvest
biotic samples as well as sediment properties, chemical contaminants, and
geo-chemical properties. |
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Deploying the box corer |
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Recovering the box corer |
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ROV (Remote Operate Vehicle): |
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The ROV-based in situ research is conducted by our SEABOTIX
LBV150S, which is equipped with thrusters, a hires color camera with zoom,
a low light black and white camera, 150 meters of umbilical. The precise |
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control, powerful thruster,
and variable buoyancy system allows low disturbance on the sea floor
during the photo-survey. It is also suitable for transects to
make quantitative measurements and in situ observation of behavior
patterns in the shallow water. |
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Adjusting the ballast weight of the ROV |
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