Date: Fri, 22 Jan 1999 19:09:03 GMT
To: ALSUTHER@nsf.gov, KERB@nsf.gov, sanamowa@lmg.polar.org,
        asalmg@lmg.polar.org, mo-sciweekly@asa.org
From: rossro@lmg.polar.org (Robin Ross)
Subject: LMG Science Weekly Jan 11-17

Dear Colleagues,

During the first 9 days of science operations for the Palmer LTER's annual
summer cruise (Jan 9-17) we completed two of the five core transect lines,
a total of 20 full stations.  The two lines, the 500.* and 300.*,
respectively 120 km and 320 km south of Anvers Island, run seaward from the
inner shelf to about 200 km offshore (~ 3000 m deep).  We also collected
alongtrack data between each pair of stations and between the two lines for
our analysis of determinants of spatial patterns, i.e. two complete
on/offshore and one alongshore transect, each ~ 200 km long.  The along
track data include seabird distributions, bioacoustics (120 kHz),
temperature, salinity, fluorescence, dissolved O2, CO2, pH and nitrate,
with discrete samples taken at hourly intervals for nutrients and
chlorophyll a.  During the last 8 hr segment of the 200 km alongshore
transect, which was in 3000 m deep water, we had to suspend collection of
bioacoustic data due to the 18-25 ft swells.

Our goal is to complete 3 stations a day when running the on/offshore
transects.  On two days during this time period we were only able to
complete one station, once due to weather and 18-20 ft swells, and once due
to a malfunction in the CTD that took most of the daylight hours to
diagnose and fix.  In addition, the spherical PAR collector on the CTD, the
same sensor used in 98 January, is far less sensitive than anticipated,
with a 36% error at the 1% light level for the most recent calibration.
The relative insensitivity has been compounded by consistently overcast
skies, and has complicated the timing of stations for optical measurements
and primary productivity experiments.  Some adjustments in the schedule
have helped us avoid compromising these core data, but those adjustments
create their own limitations on what we can accomplish.

Complete results will not be available until the samples, frozen and
preserved, are analyzed back at our respective home institutions.  However,
preliminary results suggest that bloom conditions are not present on the
shelf at this time.  Over most of the grid surveyed to date measurements of
the bio-optical properties of the seawater have documented an optically
clear water column.  Chlorophyll a and primary productivity values have
been low, close to baseline.  The exceptions to this generality were the
stations on the inner edge of the 500.* line in the Grandidier Channel
where both chl a and primary productivity were elevated.  However, surface
waters have been undersaturated in CO2 relative to the atmosphere since
leaving Palmer Station on Jan 8.  Hydrogen peroxide concentrations are from
15-25 nM within the mixed layer and decrease with depth.  Enzyme analysis
shows glucosidase production rates to be low, while leucine aminopeptidase
rates are much higher relatively at all stations sampled.

=46or the higher trophic levels, salps and Antarctic krill have co-occurred
at most stations on the shelf, with the exceptions of the stations in the
Grandidier where only krill were found.  Salps are abundant, with a maximum
catch on these lines of 15 liters.  However, the presence of salps is not
limiting feeding and reproduction in krill.  Spawning experiments have
shown that female krill are spawning earlier at the outer stations of the
500.* line than in most of the previous 6 years.  High seas and fog
restricted observations of seabirds for the first few days of the cruise.
While 20-30 knot winds made observations for penguins quite poor, sightings
of wandering, gray headed, black browed, and light mantled sooty albatross
were frequent.  Ship followers have included southern fulmars, white
chinned, cape, giant, antarctic, and snow petrels.  On 19 January one of
four giant petrels nesting near Palmer Station and fitted with a satellite
transmitter was spotted from the bridge at 64=B0 27.375S and 65=B0 38.491W.
This sighting is quite significant considering the low number of giant
petrels fitted with transmitters this year, and will provide an accurate
test of the Argos positions for this project.

The level of support from both the ASA personnel and Captain Warren and his
crew has been outstanding.  The delays due to equipment malfunction and
weather can be frustrating, but the quick and positive resolution to these
problems has been appreciated.  All field personnel are well, and work
continues.

Robin M. Ross (BP-028), Chief Scientist, and Field Team Leaders
P. Duley (BP-013), W. Kozlowski (BP-016), K. Patterson (BP-032), L. Tupas
(BP-046)