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Date: Tue, 1 Feb 2000 08:51:13 -0800
To: lterpalpi, quetinla@nbp.polar.org, fraserbi@palmer.usap.nsf.gov
From: Maria Vernet <vernetma@lmg.polar.org> (by way of Robin Ross)
Subject: LM GOULD WEEKLY SCIENCE REPORT 17-22 Jan
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ARSV Laurence M. Gould
REPORT 17-22 JANUARY 2000
Long Term Ecological Research (LTER) Cruise


During this week we continued sampling in the LTER grid on the continental
shelf (300 and 200 lines) and spent a day at sea in Marguerite Bay in
collaboration with BAS scientists.  Ice was 8/10 to 10/10 in most of
Marguerite Bay and to mid shelf at 67.5 S along the 200 line. We were
unable to sampling inside Marguerite Bay, Southwest of 200.-020 due to
heavy ice. We observed large phytoplankton accumulations at the ice edge in
the Northern part of Marguerite Bay but lower concentrations
elsewhere.  Weather deteriorated on Jan 20th and continues windy. We have
only missed one offshore station due to bad weather conditions.

Overall things have worked smoothly for all participants. Primary
production continues to be lower than the average of 1995-1999 years for
the same locations for this time of the year, resulting also in higher
nutrient concentrations in the water column. In spite of lower
phytoplankton concentrations, large centric diatoms are present both
inshore and offshore, dominated mostly by Corethron cryophilum and
Chaetoceros spp. We are now nearly caught up in analyzing the chlorophyll
samples.  At the beginning of the week, the fluorometer was calibrated with
a chlorophyll dilution series.  However, we had a problem of randomly
recycling its power to the point where the unit was unusable. It turned out
that resetting the date to 1999 made the problem disappear (Y2K issue). The
maximum found has been 8.8 microgram chlorophyll a per liter at station
200.000.

The casts of Profiling Reflectance Radiometer (PRR) to measure water-column
optics have been half as deep (average 33 m) as we cut a significant amount
of cable (length went from ~250m to ~125m).  We have been doing double
casts to select the best/deepest of the two.

We continued sampling for dissolved inorganic carbon (DIC), dissolved
oxygen (DO) and microbial abundance and activity parameters. Deep water DO
values on outer stations(<500 m) match well with last years data. Mid water
(40-300m) values on 600 line are much lower than last year (the gradient
has moved up in the water column). This is interesting because the profiles
on the 400 line match quite well with last years data.  Maybe there was
deeper winter mixing or more upper circumpolar deep water has move onto the
shelf along the 600 line.  At certain stations there were sub-surface DO
maxima which are rare to see.  In Marguerite Bay (Avian Shallow) the
surface DO's were extremely high (>460 uM) and an intense bloom situation
was obvious.

Ectoenzyme activities showed expected trends in the 600 to 300 lines, with
highest proteolytic rates in the top 20-40 m and rapidly decreasing with
depth. Inshore stations showed higher activities than off shore stations
possibly correlated to higher bacterial biomass/cell abundances near shore
(flow cytometry and lipopolysaccharides, LPS, samples to be analyzed).

On Tuesday 18 January  4 participants were able to get ashore at Ginger
Island,  where there are approximately 3,000 pairs of adelie penguins
nesting.  Our job here was to  stomach lavage  20 adelies in order to have
a look at what their diet consists of in the Marguerite Bay area. This data
will be analyzed with our ongoing  adelie diet sampling work at Torgerson
Island  near Palmer Station. The ice was looming off Ginger Island most of
the day and we had to keep a close eye on things as we  processed our birds
on the beach.  In the end we managed to get samples from 16 of the 22 birds
that we stomach lavaged.

Our observations from the bridge while in ice on the 200 line reveled the
highest concentrations of marine mammals on this cruise.  Crab eater seals
were the most common marine mammal observed on the sea ice. On 20 January a
lone Emperor Penguin was seen on a flow at the edge of the ice field on the
200 line.  On 22 January a very rare vagrant was spotted during our bridge
watch,  2 black necked swans normally found in South America. The last of
our concentrated effort will be our foraging grid observations South of
Anvers Island in the latter part of this cruise.

We continued to find salps and heavy phytoplankton in our nets at outside
stations on the 300 and 200 lines, although the salps were not in such
large numbers as on the more northern lines.  Krill numbers were not high
at any outside stations but we managed to get a good spawning experiment
from just 40 animals at station 200.160.  These krill were caught with a
lot of salps which usually damages the krill in the net but about half of
the krill in this catch were still healthy and swimming.  We weren't sure
if we would get any animals further out on the 200 line so we decided to
use them.  This was a fortunate decision, not only because we didn't get
krill at 200.180 and were weathered out of sampling 200.200, but also
because 13 of the 28 females in this experiment have spawned.  The inside
stations on the 200 line had too much ice for us to tow the Biosonics but
we were still able to sample with the nets.  We were interested in finding
out if we would catch more krill in the ice as  at Palmer earlier this
season we had usually only seen krill in any numbers when there was ice
around.  Stations at the ice edge, between 200.040-200.120, had the larger
amounts of krill than any other transect.


On January 18 we hosted scientists from the British Antarctic Survey (BAS)
at Rothera on the LMG for the day.  The party was led by Dr. Lloyd Peck and
Paul Rose, Base Commander.  It was a wonderful opportunity for us to
interact with the BAS scientists and learn about each other's research.  We
cross-calibrated the CTDs used in the nearshore sampling off Rothera and
Palmer Station with our shipboard CTD package and were able to collect live
krill for feeding experiments at Rothera. We also had some great
zooplankton discussions and exchanged information on how we conduct our
research.  They are just beginning a near-shore sampling program for krill
and are very interested in making their data collection consistent with
ours to facilitate intercomparison. In addition, 4 BAS scientists
participated in the penguin sampling at Ginger Island. They were ashore for
excavation work looking at avian paleo ecology. We thank all of them for
the warm reception at Rothera Base.

Information on the cruise, the Palmer LTER program and the journal from the
teacher in this field season (Mimi Wallace) can be found at the Jan 2000
cruise page http://www.icess.ucsb.edu/lter/field/00jan.

We thank the ECO crew (Robert Verret, Master), ASA personnel (Randy
Sliester, MPC), and personnel in Palmer Station (Robert Ferrel, Station
Manager) for their support on carrying out a successful sampling program.
(Maria Vernet, Chief Scientist, for S-013, S-016, S-021, S-028, S-032, S-046)