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PSN Antarctic Adventure
Real Project Title:
Particulate Organic Carbon Production and export in the Indian Ocean Sector of the
Southern Ocean: A U.S. - Chinese Collaborative Research Program.
Participants:
Dr. Cynthia Pilskaln, University of Maine Dr. Vernon Asper, University of Southern
Mississippi
Sponsor:
National Science Foundation, Office of Polar Programs, Dr. Bernhard Lettau, Program
Manager.
Purpose:
To collaborate with Chinese ocean scientists to investigate the marine ecosystem in the
Southern Ocean with particular emphasis on the production and export of organic carbon on
an annual basis through the deployment of sediment traps. See the map
of the adventure.
Summary:
The Southern Ocean, which surrounds the Antarctic continent, is the site of one of the
most productive environments in the world and one which experiences brief but intense
blooms of algae. Given that no other green plants exist anywhere in the region, all life
in this ecosystem depends directly or indirectly on these algae for their sustenance.
Material produced during the short growing season, when the sun shines 24 hours a day,
must support everything from krill to whales for the entire year because when the sun sets
in May, it will not rise again until the following spring. In spite of the importance of
these single-celled plants, little is known about their growth rates or the ecological
pathways through which they feed the herbivores which feed on them. In order to address
this lack of understanding, we will be deploying devices known as "sediment
traps" which collect time-series samples of material which is settling out of the
upper water column, on its way toward becoming sediment at the bottom of the ocean. By
examining this material, we will be able to discern: a) what kind of algae are growing, b)
when and to what extent they bloom c) their contribution to the global carbon cycle, d)
which organism feed on them, at what rates and during what seasons, e) the speed at which
this material settles through the ocean, and f) the annual cycles in all of these
parameters.
Logistics:
U.S. scientists will collaborate with researchers from the Polar Research Institute of
China, located in Shanghai, People's Republic of China. We will join their research
icebreaker, the Xue Long or "Snow Dragon", in Freemantle, Australia from where
we will sail southwestward toward Prydz Bay on the continent of Antarctica. Upon arrival,
we will offload Chinese scientists at the Zhongshan research station and then depart for a
point to the northwest, in ice free waters where we will deploy the sediment traps on a
deep-sea mooring. This deployment involves a fair amount of effort, starting by placing a
series of floats attached to a cable in the water, and then paying out cable as the ship
steams away, stopping periodically to insert instruments in the line, and finally ending
by attaching a 2-ton anchor which is slid into the water, dragging the entire array to the
sea floor. When properly installed, the array extends from the anchor, which is at nearly
3 miles' depth, up to within about 3,000 ft of the surface, with sediment traps, current
meters and other instruments distributed along the length of the line. Just adjacent to
the anchor is a release mechanism which will, if it functions properly, release its grip
on the anchor when commanded next year, and allow the array to float to the surface where
the instruments, samples and data can be recovered. Following this deployment, we will
sail back to Prydz Bay where we will meet a Russian ship, the Kapitan Khlebnekov which
will return us to Hobart, Tasmania and from there we will take commercial flights home.
Communications needs:
During cruises such as these, we often encounter unexpected difficulties with either
the electronic packages associated with our instruments, with illnesses, or with planning
efforts and coordination with our home offices. In each case, communication with our home
laboratories or with a physician can become critical when the nearest store or hospital is
up to 10 days away by ship. Additionally, our mooring array has an Argos transmitter
attached to it which will signal its position whenever on the sea surface. This system
will be used only if we run into trouble with the deployment of if the mooring line parts
prematurely but in either case, having immediate access to the position information
provided by the Argos system will be critical. Although both vessels have Inmarsat
capabilities, we have been told that we may not be able to depend on them both because of
uncertain reliability and because access is often restricted. We are therefore earnestly
seeking an independent means of communicating with our home laboratories while on this
expedition.
Dr. Vernon Asper
University of Southern Mississippi
Institute of Marine Sciences
Building 1103, Room 102
Stennis Space Center, MS 39529
228-688-3178 / FAX 1121
228-872-4261 / FAX 4204
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