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This
is an image of Great Bahama Bank taken from the Space Shuttle. The light blue color of the shallow
bank-top (<6 m deep) is evident. At the extreme right
edge of the image is Andros Island, largest of the
Bahamas archipelago. The white smudges in the water west
(left) of Andros Is. are "whitings" -
mysterious patches of highly turbid water commonly
sighted on the bank-top. The origin of whitings is not
known at the present time. Leading hypotheses suggest
they result from 1) precipitation of calcium carbonate by
microorganisms, 2) resuspension of fine-grained bottom
sediment, 3) feeding activity of schooling fish. |
| These
dolphins were captured on video as they moved in to
investigate my activies while I was conducting research
in the Bahamas. These adults circled our position for
about 20 minutes before moving on. This brief encounter
with wild dolphins in their native domain ranks among the
most extraordinary experiences I have ever had while
SCUBA diving (another was being "narc-ed"
senseless with my friend and mentor, Dave Liddell, at 70 m depth on the north coast of
Jamaica! Sorry, no pictures of that!) |
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Friend,
colleague and underwater bulldozer, Ennio Marsella from
the University of Naples (Italy) takes a breather as he
helps prepare an underwater excavation site in the
Bahamas. Digging a hole underwater provides us with small
windows into the depositional history of shallow water
sites which were flooded by rising sea-level following
the last Ice Age. Analysis of these histories yields
clues to the dynamics of sea-level variation and the
climate changes which can cause them. |
| On
rare occassions, the sea can be indescribably serene. The
promise of days like the one pictured here are one of the
prime motivations for me to pursue research at sea.
Though the days are long and often tedious, few of my
colleagues ever have the opportunity to savor these
moments. With a good ship and the camaraderie of the
crew, life doesn't get much better than this. |
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Divers
can work in shallow water to obtain cores into sediments
and rocks. Rocks deposited in shallow waters record the
geologic effects of rising and falling seas. Here, my
friends Ken Rasmussen (left of Northern Virgina Community
College) and Ricky Gomez (right, presently Dive Officer
at the University of Miami) lower a drill bit to the
seafloor. Work like this can take many hours to
accomplish underwater. The longest core we retrieved for
this work was just over 9 meters - it took over 12 hours
to get it using 3 teams of divers. |
| 1997
has been declared the International Year of the Reef by
Dr. R.N. Ginsburg at the University of Miami. Coral reefs
worldwide are in trouble - corals are dying in
unprecedented numbers, fish on reefs are being
overharvested, introduced pollutants promote rapid growth
of algae which are able to out compete corals for space
on the reef. As a result, the overall diversity and
health of the reef declines. There are several proposals
to implement an international
network of monitoring stations to track reef declines and assess their
causes. |
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This
is a computer-processed composite radar image of the
eyewall of Hurricane Andrew crossing Great Bahama Bank
and the Straits of Florida in 1992. Image #1 shows the
storm in a greatly weakened state on the bank-top
(indicated by the weak & discontinuous radar
reflections from the eyewall). Image #2 shows the storm
intensifying as it begins its transit across the Straits
of Florida. Finally, # 3 shows Andrew at full force just
prior to landfall in south Florida. Andrew still ranks as
the most expensive natural disaster in U.S. history,
causing over $30 billion dollars of damage. |
| The
sea is not always benign. This image shows a wave
breaking across the bow of the U.S. Army Vessel Snell
off the North Carolina Outer Banks in 1995. On days like
this, work at sea comes to a standstill and your only
option is to "ride it out". Hopefully, you've
come prepared with a good collection of videos and a
pocket full of change for the marathon poker match. |
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This is a
photomicrograph of a cross-section of a sea urchin spine
(Diadema antillarum) taken using polarized
light. This spine was a constituent of sand collected
from a coral reel on the north coast of Jamaica in 1982.
The urchin species which produces these spines
experienced a pan-Caribbean plague in 1983 which resulted
in the local extinction of Diadema from some
areas for several years. The cause of the plague has
never been pin-pointed, though its progress around the
Caribbean basin was well documented. |
| The
lighthouse at Cape Hatteras, North Carolina is the
tallest on the East Coast. The present lighthouse was
built in 1873 and warns ships at sea away from Diamond
Shoals (also known as the Graveyard of the Atlantic).
Diamond Shoals is a very large accumulation of sand on
the continental shelf which shoals to depths of less than
3 m, even 10 - 12 miles offshore. Numerous ships have run
aground on these shoals and stories of the early lifesaving efforts of people on the Outer Banks are the
stuff of legend. You can view other lighthouses of the
North Carolina Coast here. |
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A coring rig
is lifted by the 35 ton crane aboard the U.S. Army Vessel
Snell. This rig is 6.5 meters tall and can
obtain cores through seafloor sediments in water depths
up to 30 meters. During the summer of 1995, I particpated
in research aboard this vessel which resulted in 229
cores from areas offshore of the North Carolina Outer
Banks. Data from these cores are presently being
integrated into a comprehensive study of sand resources
on the North Carolina continental shelf. |
| This is the
research submersible 'Pisces 2' which was used for
research on deep reef environments off the north coast of
Jamaica in 1987. Shown here is the "business"
end of Pisces - 3 viewing ports, a manipulator arm, and a
rack for photographic equimpment and lights. This work
was a project under the direction of Dr. W.D. Liddell, a
paleontologist and coral reef ecologist at Utah State
University. The maxmimum working depth of the Pisces clan
of submersibles is 800 m. |
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Sea oats
colonize the crests of the first dune line on a barrier
island. Occupying the transition between sea and land,
barrier islands are among the most dynamic geologic
environments on Earth - often changing noticeably from
year to year. Unfortunately, this very unstable landscape
is under increasing pressure as more people relocate to
the coastal zone. As a consequence, habitat is often
disturbed, coastal erosion often accelerates and more
people are at risk from violent storms. |