U.S. Southern Ocean GLOBEC
ESR Component: Acoustic Doppler Current Profiling,
Microstructure, Tidal Modeling, and Mooring Contribution. |
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Principal Investigators:
Others:
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This work is funded by the National Science Foundation Office of Polar Programs
(Antarctic), Award 99-10102 to ESR.
The central Western Antarctic Peninsula (WAP) continental shelf is an area of
unusually high Antarctic krill (Euphausia superba) production and, as a
consequence, a favorable habitat for krill predators, such as Adelie penguins
(Pygoscelis adeliae) and Crabeater seals (Lobodon carcinophagus).
It has been hypothesized that a unique combination of physical and biological
factors contributes to enhanced krill growth, reproduction, recruitment and survivorship
throughout the year in this area. In particular, the WAP region provides conditions
that are especially favorable to winter survival of larval and adult krill. These
factors include:
- a sluggish cyclonic shelf circulation that retains the krill population
in a favorable environment on the shelf for extended periods of time;
- an early and long-lasting ice cover that provides dependable food and protection
for larval krill to grow and survive over the winter;
- and on-shelf intrusions of Antarctic Circumpolar Current-derived Upper
Circumpolar Deep Water which supply heat, salt and nutrients that affect ice
properties and enhance biological production.
S.O. Globec Study Area
To address the SO Globec program hypothesis, an interdisciplinary program
has been developed that consists of four integrated modules designed to investigate
processes associated with the water column environment, sea ice, krill physiology
and distribution, and top predator abundance and ecology. The fifth module,
modeling, provides synthesis and integration of the many measurements obtained
from the other modules.
The primary focus of the overall program is on determining the relative importance
of different strategies that potentially enable Antarctic krill to survive the
winter under different environmental regimes (e.g., heavy vs. light ice cover
years), determining what factors influence the use of different strategies and
how these different behaviors impact subsequent recruitment and reproduction,
and determining how spatial distributions of krill and overwintering strategies
vary among life history stages of krill, which differ in the need to acquire food
and avoid predation. The results of the this program will provide needed linkages
and observations for other Southern Ocean Global Ecosystem Dynamics (GLOBEC) activities
in the WAP region that are planned by the international GLOBEC community.
ESR's role in this program is to contribute to a description of the physical properties
of the WAP region, and an understanding of processes that link the physical regime
to the upper-ocean biological productivity. Our primary focus in describing the
physical regime is on the use of velocity data from vessel-mounted ADCPs to provide
a broader view of the ocean circulation of the WAP shelf and Marguerite Bay than
can be obtained from the WHOI/ESR moorings. Our primary interest in process studies
is on the role of winds, tides and double diffusion as mechanisms for increasing
the upward flux of heat, salt and nutrients into the biologically active upper
ocean from intrusions of Upper Circumpolar Deep Water (UCDW) over the deep shelf.
Information regarding the setup of the ADCP, status of the data, and results for each cruise may be obtained by following the links below:
2001
Mooring deployment
GLOBEC I
GLOBEC II
2002
Mooring cruise
GLOBEC III
GLOBEC IV
- NBP0204: July 31 - Sept 19
- LMG0205: July 29 - Sept 19
2003
Mooring recovery cruise
Information regarding available ADCP data may be obtained by following the links below:
2001
SO-GLOBEC cruise of Polarstern to the Bellingshausen Sea.
- ANT-XVIII/5b: Apr 14 - May 4, 2001
Eric Firing, Jules Hummon, and Teri Chereskin have provided us with invaluable
assistance in the configuration and support of the shipboard systems, as well
as initial processing. Their work to edit the data and to improve the ship ADCP
systems, has played a major role in the quality of the data sets acquired during
S. O. GLOBEC.
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Questions or comments regarding this site may be sent to: Susan
Howard
Site last updated on November 28, 2001.
