NSF PR 02-36 - May 7, 2002
Ships Return to the Southern Ocean to Enhance Understanding
of Food Chain
To follow the progress of SO GLOBEC, see
by Kristin Cobb. Dr. Cobb, a student
in the science communication program at
the University of California, is sailing
aboard the Southern Ocean Global Ecosystem
Dynamics (SO GLOBEC) program to the Southern
Ocean and is filing reports from the voyage.
Two National Science Foundation (NSF) research vessels
have sailed from Chile toward the wintry waters off
the Antarctic Peninsula, where they will examine the
interlocking links of a food chain. Tiny shrimp-like
animals called krill anchor that food chain, feeding
on microscopic plants and animals and forming the
basis of a living web that supports some of Earth's
largest marine mammals.
The R.V. Laurence M. Gould and the R.V. Nathaniel
B. Palmer will serve as the home to about 100
scientists and support personnel for six weeks as
they cruise the waters of Marguerite Bay on the Western
side of the Peninsula in the second data-gathering
cruise of the Southern Ocean Global Ecosystem Dynamics
(SO GLOBEC) program.
Eileen Hofmann of Old Dominion University, the project's
chief scientist, noted that the project last year
gathered the most comprehensive set of data currently
available on a host of factors such as the distribution
and abundance of krill in the Southern Ocean. Next
year, the data gathered last season and This will
be analyzed for trends and patterns that will allow
scientists to grasp how environmental conditions affect
life in one of the world's most biologically productive
bodies of water.
In a key feature of this year's SO GLOBEC cruise, the
ships will return to an area that was studied intensively
last spring. This will give scientists an important
comparison of conditions over time, said Hofmann.
"Repeating the cruise in the same area this year will
tell us quite a bit about year-to-year variability,"
she said. "We already know from satellite data that
the sea ice is more extensive this year, and that's
good, because one of the projects' science objectives
is to test the extent to which over-wintering krill
are dependent on the extent and position of the sea
The Southern Ocean's vast productivity depends on the
small but enormously abundant Antarctic krill. Krill
feed on microscopic plants and animals and, in turn,
are fed upon by whales and fish. Seals, penguins and
other sea birds eat the fish. Hofmann said that using
data collected last year on where krill are most abundant
would allow the scientists to focus their efforts
on the most productive areas of study this season.
"We're a lot smarter this year. We know a lot more
now about where we might expect to find seals, for
example," she said. "Last year we were able to identify
what people were calling "hot spots" or places where
krill aggregate. There were also lots of whales, seals
and birds there. The first time around we had to find
these hot spots. This time, we're going to spend more
time using those areas for specific studies."
Scientists on this year's cruise, while hoping eventually
to grasp the "big picture" of Southern Ocean ecology,
also have added measurements to look at the mixing
of temperature and salinity in the water at centimeter
and millimeter scales. Such mixing occurs on a far
larger scale in more temperate waters, another factor
that may make the Southern Ocean unique. "We think
that's the dominant mixing process in this area,"
At the other extreme of size, biologists of the International
Whaling Commission will examine these mammals to see
how actions at the microscopic scale eventually affect
the Southern Ocean's dominant predators.
As they did last year, the Palmer and the Gould
will work together to sample different aspects of
the survey area. The Palmer will conduct a
wide oceanic survey at points along a fixed grid and
will collect data along the grid lines. The Gould
will spend four to five days at each of five stations
in strategic locations.