Fourth Weekly Report - NBP01-05 Palmer LTER Sea Ice Cruise
01-07 October, 2001

We have been beset in thick snow & ice during much of this week.  At 0600 on
7 October we were just 14 miles from our position at 0600 on 30 September. 
Capt Joe and his mates have worked exceptionally hard this week to keep us 
from being pushed even further south.  The ice drift, under nearly constant
winds from the north, has often exceeded 0.6 knotts.  The ice continues to be
under extreme pressure.  While ramming into a relatively large floe early this
week it ridged right in front of the bow.  As we watched, the floe broke, one
part sub ducting and the other part over rafting while plowing snow & ice into
a 3m high ridge.  Later in the week we watched a shear line in the pack ice,
stretching from the SW to NE as far as we could see using binoculars, in which 
one side was moving about 0.2 knotts with respect to the other.  It was like 
watching the San Andres Fault in fast forward.  Plate tectonics writ small and
in real time.  On the 3rd we established an ice station, set out a thickness
transect, dug a snow pit, obtained cores for both physics and biology, measured
optical properties of snow & ice, obtained snow samples for Persistent Organic
Pollutants, opened a dive hole for 1 dive and obtained krill, opened a hole for
a sediment trap and did 3 CTD's.  All before being forced to abandon the station
late in the day.  A mini ice station was held on the 5th and two other attempts
to establish stations were abandoned because of unsafe ice &/or storm conditions.
Given current ice conditions it seems unlikely that we will be able to arrive at 
Palmer Station on schedule, unless and/or until we have strong winds from the 
south to loosen the pack ice.  Captain, crew, RPSC and science groups are 
working as a team and moral remains high in spite of encountering conditions 
that have severely limited our planned activities.  Individual group reports
follow.

S-013  (Chris Denker and Heidi Geisz for Bill Fraser)
We continued monitoring for wildlife from the bridge this week.  Our efforts 
paid off one evening when we spotted four Adelies on an accessible flow while 
we were steaming through a sizable lead.  We were able to gather forces, hike
to the birds and capture three of them relatively easily.  They seemed less 
inclined to run than the previous groups of penguins we have approached on this
cruise.   We collected three large diet samples containing krill, and fish in 
two of the samples.  We noticed an abundance of Antarctic petrels this week
following leads in groups of as much as twenty-five.  We also observed four
crabeater seals that had pupped.   Other activities included monitoring our 
tagged Adelies, of which most are still active in the Marguerite Bay polynya. 
Three of the tagged penguins are traveling north.

BP-016 (M.Vernet, W. Kozlowski, K. Sines, K. Pelletreau, I. Garibotti, & P. Yeh. 
Nutrient analyses are provided by Andrew Ross from Oregon State University. )
During the week of 1-7 October, the phytoplankton group within the LTER 2001 Ice 
cruise sampled in waters adjacent to the mouth of Marguerite Bay.   Phytoplankton 
biomass and primary production in the water column remain low (i.e. < 0.1 
milligrams chlorophyll a per cubic meter and < 40 mgC m-2 d-1). Ice communities
were sampled during several ice stations. Characteristic of this area is the
gradient in cell abundance from surface of the ice towards depth.  For example,
Core 33, 94 cm long and sectioned every 20-25 cm, showed a chlorophyll a 
gradient of 12. 1 mg m-2 (0-25 cm), 3.9 mg m-3 (25-45 cm), 3.4 mg m-3 (65-85 cm)
and 0.7 mg m-3 (85 to bottom) from surface to depth. Core 29, collected in the
vicinity of core 33 and sectioned at 10-cm intervals, showed a similar pattern
in chlorophyll distribution, but with higher surface chlorophyll concentration
(47 mg m-3). In addition, an intermediate layer of high chlorophyll concentration
was measured at 33-52 cm. Nutrient concentrations also decrease from 
surface to depth: phosphate from 0.9 to 0.3 micromolar, nitrate from 5.2 to 4.1 
micromolar, silicic acid from 28.1 to 10.6 micromolar while ammonium 
concentration was constant at 0.3 micromolar.  Microscopic analysis revealed
this core to be 85% granular, 4% columnar and 11% mixed.  Ice communities showed
adaptation from high to low irradiance from top to bottom: for example, surface
samples (top 0-25 cm) saturated photosynthesis at higher irradiance, compared to
bottom communities.  Maximum photosynthetic rates were high at the surface
(Pmax = 3.89 mg C mg chla-1 h- 1, alpha or light-limited photosynthesis = 0.016
mg C mg chla-1 h-1 per microE m-2 s-1 and light saturation (Ik) at 57 
microE m-2 s-1).  At depth, Pmax = 1.2 mg C mg chla-1 h-1, alpha or
light-limited photosynthesis = 0.069 mg C mg chla-1 h-1 per microE m-2 s-1
and Ik = 59 microE m-2 s-1. Analysis of ice cores is done in collaboration
with Smith's group and biological analysis in cores is done jointly
with Karl's, Ducklow's and Quetin's groups.  

BP-021 (Rich Iannuzzi & Raul Guerrero, for Doug Martinson)
The physical oceanography team made 6 CTD casts from 00:00 Oct. 1 to 23:00 
Oct. 7 bringing the cruise total to 45.  Again this week we made a rotation
of the rosette from the back deck to the Baltic room and back again.  All the 
casts of this week were performed from the A-frame.  The decision to move the
rosette back to the Baltic room occurred after much of the water from a cast in
-15 C conditions froze in the spigots and even in the surface bottles while on
the back deck.  Only some groups successfully got their water.  The certainty of
further ice stations was in question at the time and so for the protection of
the equipment this decision was also made.  At the next ice station, the rosette
was returned to the back deck, where it currently resides, wrapped in a tarp and 
heated when necessary.  The oxygen sensor appears to have been biofouled
for the casts on Oct. 6 and was cleaned, but not yet used for a cast.  Continued
maintenance of the 2 conductivity cells shows stable offset.  CFC samples on two
casts were collected for Bill Smethie of Lamont Doherty Earth Observatory. 
CFC samples were frozen and lost at the above mentioned station.  The salinity
profiles of this week all show a clear seasonal mixed layer, while the mixed
layer temperature remains at the freezing point, as expected with so much ice
still around.

BP-028 (Langdon Quetin, Charlie Boch, Amy Kaiser, Tim Newberger, Stephanie Oakes,  
Holly Rodrigues, Jordan Watson, Jenny White).
From October 1 - 7 our on-ice activities have been limited by the winds of fate.  
However, on board experiments to determine the ingestion and fecal pellet 
production rates and feeding selectivity of larval krill have continued mostly
uninterrupted by our need to make progress through the pack ice.  The results
of these experiments won't be known until more detailed analyses can be completed
at our home institution.  On October 3 we completed one dive before the weather
turned favorable for travel.  Dive 11 was in the most heavily over rafted area
we have seen to date with rafting down to 10 m.  Krill larvae continue to be
abundant under the ice.  We were able to collect enough larvae to replenish
our krill stocks maintained in the aquarium room, complete two experiments on
growth rates, and preserve samples for length/stage frequency, chemistry and
chn analysis.  

BP-032 (Ray Smith, Enrique Curchister, Rob Massom, Yuko Massom & Sharon 
Stammerjohn)  Ice conditions have remained difficult and heavy, with northerly 
winds continuing to predominate and to pack the ice into Marguerite Bay and
to make the going very tortuous. As a result, the sea ice cover has again been
dominated by heavily rafted and ridged thick first-year ice, with frequent
snowfalls and strong aeolian redistribution leading to the continuance of a
very thick snow cover (estimated to average ~40 cm). In spite of the resultant 
logistical difficulties, the snow cover and ice thickness has been characterized,
snow samples and ice cores have been collected (some have been over 2 meters
long), and optics measurements carried out during successful ice stations over
the past week. The warm conditions accompanying the persistent northerly winds
have caused significant melting in the snow column, with icy melt-refreeze layers
being an important factor in the snow examined on September 30.  Temperatures 
within ice cores are essentially isothermal and contain melt/slush voids. 
Flooding of the snow-ice interface due to the combined effects of snow loading
and ice deformation has again been a widespread phenomenon, leading to much snow
ice formation out of the frozen slush. This stratum has continued to provide a 
rich habitat for phytoplankton growth, as observed both during the ice stations
and hourly ice observations. A short-term cooling event on October 3 led to
significant freezing of the slush layer,  producing a generally dryer snow
layer, with waterlogged snow being replaced to some extent by snow ice.  In
addition to the usual physical measurements (i.e., temperature, density, 
salinity), snow and ice core samples have been collected to for the subsequent
analysis of the chlorophyll, nutrient content and oxygen isotopic analysis. 
Snow ice and slush 
samples have also been collected for this purpose, to supplement the biologists'
data and samples have been collected for detailed nutrient, oxygen isotope and
chlorophyll analysis. Thick and thin section characterization of ice cores
continues as well. Measurements of the spatial variability
of snow and ice thickness, snow-ice temperature, and flooding have also been 
carried out along transects at 1-m intervals across the station floes.

BP - 045: (Rebecca Dickhut, Hugh Ducklow, Amy Chiuchiolo and Shelby
Walker) The VIMS ("Persistent Organic Pollutants in Antarctic Sea Ice") group 
continued to sample water, snow and ice as well as air, when conditions 
permitted. 
Due to poor weather conditions and our inability to get on the ice, we were only
able to collect one air sample, one snow sample, and one surface water sample
during Week 4.  It is imperative to increase our sample numbers for the cruise
and we will attempt to do so in the remaining weeks. Several ice cores were 
sampled for bacterial abundance and production.  In particular we obtained a
valuable pair of over- and under-rafted ice cores at Ice Station 3 on Oct 3. 
Five vertical sections from the upper, 68-cm core and the underlying core were
assayed simultaneously. In this region the ice pack is very heavily over-rafted,
resulting in considerable vertical (and volumetric) expansion of the sea ice 
habitat.  These cores should help enhance our understanding of the vertical
structure of the sea ice community. We continue into the 4th week of sampling
a carboy inoculated with sea ice on 16 September. The inoculated treatments 
are in the later stages of a heavy Phaeocystis bloom, with consequent intense 
bacterial growth.  Bacteria are beginning to proliferate in the controls as well,
but with a ca 10-day lag relative to the experimental treatments. We hope these 
experimental cultures will shed some light on ice-algal/bacterial couplings 
during the period when ice recession begins to seed the water column with both
algal and bacterial populations.

BP-046 (D. Karl)  Chris Carrillo, Matt Church, Shaun Johnston, Tamara Pease 
As the NBP-01-09 LTER winter cruise inters it's fifth week, BP-046 reflects 
on their accomplishments and disappointments. Although the cruise plans changed
considerably because of unforeseen severe ice conditions, the characterization
of the microbial community within the sea ice and water column has been a success.
The data, combined with the previous LTER winter cruises (NBP-93-08 and
NBP-99-07),
will provide a unprecedented view of the microbial community during the austral
winter months; a period of time when very little data exists. To date, over 100
leucine incorporation and ectoenzyme activity (LAPase) experiments have been
conducted to compare microbial activity within sea ice and the underlying water
column. Net community respiration was also estimated by measuring oxygen uptake 
within dark incubations. Water column depth dependant profiles of Archaeal
abundance and Archaeal lipids will also be compared to samples taken in ice to
help determine the ecological role of these novel organisms within the Antarctic
ecosystem. Additionally, samples for lipopolysacharide (LPS), dissolved organic
carbon (DOC) and organic nutrients have been taken to characterize microbial
biomass, carbon and nutrient pools.  

As part of the scientific objective to determine carbon flow within the 
ice-ocean marine system, sediment traps were placed under the ice to estimate
ice assisted C:N:P:Si export flux. These samples will be compared to particulate
matter obtained from the melting of sea ice and to experimentally derived 
particulate matter obtained from the freezing and thawing of surface seawater.
Also, the effects of sea ice formation on the precipitation and subsequent 
dissolution of calcium carbonate is being investigated by measuring changes 
in total alkalinity. Finally, samples for oxygen, dissolved inorganic carbon
and total alkalinity are being taken as part of the core measurement program.
The underway pCO2 system is being monitored and will be incorporated into the
cruise data set. If possible, BP-046 will continue to study the microbial
community, oxygen and carbon dynamics as the sea ice ablates.  

Respectively Submitted,
Ray Smith,
Chief Scientist