Date: Wed, 22 Jan 97 07:26

Subject: Chief Scientist's Report, #1

Hi All,

Sorry this is a little late for a weekly report, but we have been busy.
The stations came thick and fast at the end of the line, and Orca was
just as busy. With hardly a break in the action, we were quickly at the
Ross Ice Shelf.

We left McMurdo at midnight- or more accurately 0001h- on the 13th, after
a marathon of loading, rearranging and securing all the gear, not to
mention set-up. Buzz Scott, Corey Peterson, Julie Arrington, and Herb
Baker (all ASA) worked very hard to get us underway, and Janet Barnes
kept everyone at McMurdo happy and clued in to our progress.

Once underway, the Palmer plowed through the seaway kept open by the
USCGC Polar Sea, and all of us newbies were impressed by the crunched
up ice thrown to the side like so much chaff. We saw leopard seals
slide off (actually, more like "ooze off") the ice into the water
at our approach, and and minke whales come up for a peek.


We arrived on station about 12 h later and began sampling. We chose
pseudo-Minke at 169E since that was what was sampled on P1.

Jeff Kinder (NCS), Billy  Sweet (NCS), and Buzz Scott completed the
first couple of CTD's. Water temps near the surface were +0.5degC
in the top 10-15 m, and there was a freshened lens over those
depths. We saw a broad fluorescence max at about 50 m, but with
the bulk of the fluorescence beneath the euphotic zone, which we
estimated at about 25 m. After these first casts, Mary Jo Richardson
(TAMU) noticed an interesting transmission minimum at 30 m, and she
made sure she got an SPM sample there. The minimum seems to be
associated with slightly warmer, saltier water, so perhaps that
water's origin is somewhere more offshore. We're now checking on
possible sources. There was no similar minimum in fluorescence,
which is interesting. Ann-Maree White (UTK) made slides, so we
can check to see if there are any gross taxonomic differences.

Joe Orchardo reported that Oxygen is supersaturated at the surface
to 120%, and John Goddard and Colm Sweeney (LDEO) saw pCO2's
(from the underway system) of 160 ppm, when 'normally' they should
be 360, a tremendous drawdown.

Obviously, there's lots of 'stuff' in the water (which looked grey-
green from the surface in this Antarctic light). Rob Olson (WHOI)
threw a bucket over the side, and we were treated to abundant
colonies of Phaeocystis (1mm or so in diameter) with a large background
of other fine particulates. John Marra (LDEO) and Rob incubated
a sample at 0.5degC. Dave Caron (WHOI) made a slide and we saw
in addition to the Phaeo, a wide variety of diatoms: Chaetoceros,
Nitzchia, a few  chain-formers not immediately recognizable, and
heterotrophic dinoflagellates.  In the microscope, they look to be
chains of Nitzschia, along with some big lone centrics, and
others stacked like coins. There are also Chaetoceros, mostly
as single cells or doublets. All told, a diverse phytoplankton

Steve Fitzwater and Mike Gordon (both MLML) began cleaning their
go-flo's, essentially using the Ross Sea as their "washing machine"
(on rinse cycle). Then they commenced taking samples to complete
profile for trace metal concentrations and nutrients.

Bill Cochlan and Julian Herndon (both USC), set up the extensive deck
incubation system, and along with Corey Peterson, ensured we are
getting good flow and temperatures for the incubations.

Lary Ball and Alan Fleer (both WHOI) have collected several casts worth
of samples for Thorium analyses. Preliminary counting shows very high
rates of absorption of Th onto the particulates.

We completed our first array productivity array went smoothly, almost
as though we'd already been at sea for 4 weeks. Buzz used
his personally-designed, light-weight grappling hook to retrieve
the buoy, and we were also helped by expert ship-handling on the
bridge. The TM rosette went through a few hiccups, mostly software
glitches and adjustments to the Go-Flo's, so during the unscheduled
break (about an hour), and Mike Watson the 1st mate, took us
in a circle around a small berg, and we watched some penguins
eyeing us back from their temporary home. Corey now has
the TM rosette working like I've never seen, and we've got a good
method for getting it over the side, cleanly (in all senses of the

Anyway, Minke seems to be the secret kingdom of the diatoms. They are
both numerous and diverse. I collected some water for Zanna Chase, a
student at LDEO, filtering a couple of depths through 5 um nitex from
the go-flo's, and the filters clogged at less than two liters.

The first rate measurements at Minke-One came from Colm and John G.
for TCO2, and Joe Orchardo and Cara Sucher (both URI) with dissolved
oxygen. Their incubations for showed a net production of 5 umolsC per kg
per day, and 6 for dark respiration. Carol Knudson (LDEO) and John
M.'s C14 numbers were equivalent to the net production in the TCO2
and O2 measurements. Mike Hiscock (Duke) got a beautiful series of
PvsE curves for Minke-One, showing alpha(B)'s increasing with depth,
and PBmax's decreasing with depth. His PBmax values agreed with that
found in the in situ C14 measurements.

For nutrients, the water is depleted in NO3 by about 20 uM, at a
conc. of <10, and Silicate is down by about 25 (to around 50 from 75 uM)
according to the Hydro team (Joe Donelly, Joe Jennings, Doug Masten,
Calvin Mordy and Erik Quiroz). That explains the diatoms, and also
shows the depletion of Si and NO3 to be about the same. If we assume
a 1:1 for NO3 depletion and Chl production, that would mean about 20ug
Chl, which we of course are not seeing. Even if this is off by a
factor of two, however, it implies considerable loss of biomass
either through sinking or grazing.

For grazing, Sylvia Pinca and Alejandro Gonzalez (SIO) are collecting
large numbers of mesozooplankton, both herbivores (shallow) and
carnivores (deep), and Darcy Lonsdale (SUNYSB) and Dave C. are
getting large numbers of smaller forms like Oithona. The zooplankton
are highly bioluminescent. Shaking the bucket in the dark produces an
incredible constellation of blue flashes.

Remember we're in 24h of light, so why the BL? It may support the
hypothesis that BL serves as a pattern-breaking function. The waters
may be dim enough (with the shallow EZ) that BL will render the
bugs invisible to predators as seen from below. The light is blue,
however, and the water here, spectrally, must be shifted to the

The Transect (AEZOPS)

After Minke we entered colder (<0.0degC), more saline water with
more Si, and somewhat higher NO3 values. Joe Jennings (OSU)
gave us one of the first indications of what we might see,
since he noticed that his phosphate analysis behaved differently.
He was right, the organisms have changed:a lmost no diatoms,
and Phaeocystis colonies looking to be none too healthy. Dave
Caron said he saw as many or more micro-heterotrophs that he
has seen anywhere, and Dave Kirchman (UDel) says the bacteria
are large and attached to the clumps of Phaeo. The top two
MOCNESS nets (0-50,0-100m), according to Sylvia and Alejandro,
are clogged, and devoid of mesozooplankton. The EZ is still
only 20-25 m, but much of the light must be scattered as
much as absorbed. Ann-Maree and Carol's filters clog after about
100 mls, but there isn't that much color.

Steve and Mike G. conducted a marathon of hydrocasts, assisted
by Herb Baker, Buzz, and Janet taking turns at the winch, to
get a profile of trace metals at station E. The weather was
not quite Process-1, but they were there at the bulwark, hanging,
cocking, and re-trieving bottles, relentlessly, through wind,
choppy seas, dicey wire angles, and a few bad bottle-trips
(talk about bad trips).

During another break in the action, Captain Joe Borkowski drove
up to an iceberg, and we all got to take some pictures. We were
looking for penguins but saw only one unfortunate: a dead Adelie
lying beak-down on the berg. But otherwise, the colors were amazing,
the purest blue of light reflected within the ice chunks and a
variety of greens around the waterline.

The Big-O

We created another "long" station at O (we called it "The Big-'O'"),
at 176E, a station dominated by Phaeocystis, and visually the colonies
looked healthy. Joe and Cara produced a textbook profile of net
production and dark respiration, helped by the fact that net
production was 22 uM O2 per meter cubed per day. Net production
declined from surface values to equal respiration just above our
estimate of the 1% light level, and dark respiration was just
about constant with depth at 4 (same units). Thus P/R was higher
here than at Minke-One, and the chlorophyll values had only doubled
from Minke to about 5 while rates nearly quadrupled.

Colm and John G. and Carol and John M., find the same rates with
TCO2 analyses and C14 uptake respectively. Clearly, specific rates
of production are high. John G. and Colm note that the entire
drawdown of TCO2 at the surface at 'O', about 10-12 umols over that
at the earlier stations, is all in pCO2, so the decline is biological.

Sasha Chekalyuk (WHOI) and Rob note that the fluorescence
characteristics of the Phaeocystis at these stations are atypical
of most other bugs, and suggest that using variable fluorescence
for photosynthesis parameters may be more species dependent
than previously appreciated.

Dennis Hansell and Rachel Parsons (BBSR) were happier here at 'O' than
at previous stations since DOC increased by about 30-50% throughout
the water column. At Minke, values were low, at 44 uM, and at 'O' they
increased to over 65 uM.

The 76-30 line and Station Orca

Overall we saw some dramatic changes along the 76-30 transect.
The western end (Minke), was fresher and warmer. Nutrients were
relatively low (NO3 = 9 uM, SiO3 = 50 uM). There were diatoms and
some Phaeocystis. The water became colder and saltier in the surface
as we moved east, and the diatom community gave way to a massive
bloom of Phaeocystis, which had higher rates of production than the
diatom community. Nitrate remained low, Si increased. Rates climbed
significantly. Further to the east, however, the Phaeo too declined,
and was replaced by diatoms, higher nutrients and colder water.
There was significant spatial variability at least at the 50-odd
km scale of sampling. The surface pCO2 seems to indicate that we
crossed a front, since the data prepared by John G. show an abrupt
change was we neared station Orca (at 178W).

Station Orca itself was also unto itself. The near-surface water
was fresher than we had anticipated. Also, Billy, Mary Jo and Mike H.
noted a warm water mass broadening and attenuating during a
succession of CTD casts taken over 28h. On one cast, temperature
increased from -1.2 to -0.4degC and salinity by 0.05 ppt over a
30 m depth range at 330 m (on both down and up casts), producing
one of the oddest CTD traces I've ever seen. The diatoms returned,
dominated by Nitszchia subcurvata, but with other forms present
according to Rob and Sasha. Mesozooplankton became low again, but
with more euphausiids than before.

We were so busy at Orca, with CTD's at 3-h frequencies, TM casts,
the beginning of an Iron grow-out experiment conducted by Steve and
Mike G., and a series of MOCNESS tows that the in situ productivity
buoy got away from us, but thanks to Captain Joe, and mates Lee
Crowe and Mike Watson (and some help from Guglielmo Marconi) we found
it off to the west.

Dave C. and Darcy Lonsdale (SUNYSB) completed three dilution
experiments along the transect and have the puzzling result of very
low levels of microzooplankton grazing. There may be higher levels
of mesozooplankton grazing, and Alejandro and Sylvia will be checking
that possibility.

Other rate measurements seem to be in line with the production
parameters. Grieg Steward (SIO) and Dave K. report bacterial production
of 200-500 mgC per meter sqared per day, which translates into a water-
column carbon demand of 2-5 gC, which further implies that 20-50%
of the primary production is going to the bacteria.

The Ross Ice Shelf

After sampling about a mile offshore an deploying a drifter, Captain
Joe drove up to the Ice Shelf. Winds were slight, and in the overcast
light, the ice shelf was both majestic and forbidding. Phaeo is blooming
here as well as in the middle of the 76-30 line. Although the
of cells are much lower, visually, the colonies look healthy, according
to Dave C.

Life: in General

We've all settled in to life aboard the Palmer. The lounge is great for
movies, and the ships library is excellent. It has a high percentage of
Penguin paperbacks, which now that I think about it is not at all
surprising. Ernest, Marcial, Marta, and Nora keep us well-fed, with a
lots of choice. "Mid-Rats" has become popular. The Palmer's computer
network, maintained by Kent Chen, has proved extremely useful for
communications among the science party (even the notification of
such events), and for e-mail contact with home. Tim Bjokne has already
given us some fixes to various pieces of equipment. Andy Archer keeps
up us up to date on ice conditions through imagery, and will begin
work with Doug Masten (SIO) to create some depth-distance plots of
the transect we just completed, for planning the next phase of the
cruise. On the bridge, Mike, Lee, Vladimir Repin, and Kevin Burke
are keeping us on station and giving us good wire angles for the
casts. Fredor de la Cruz and his crew run the winches for us. As
scientists, we're feeling a little spoiled.

I'll fill you in on the rest of the visit to the Ross Ice Shelf,
next time.