Report of Activities on the RVIB N.B.
Palmer Cruise 02-04
The N.B. Palmer and the L.M.
Gould completed the convoy to the southern sector of the SO GLOBEC grid on
11 August. The strategy of moving out to the continental shelf area to avoid
the heavy ice pack worked well. By mid-morning
on 11 August, we were just 8 nm from Station 76 and had steamed into much
harder pack ice when the Gould called
with a request that we stop and return to a position about 3 to 5 nm back on
the trackline.
About 1230, we arrived at the location (-68º 41.254′S; -76º 11.348′W)
chosen by the Gould for their first
week-long study site. There was lot of
activity in the afternoon getting the Gould
into place. A transfer of some samples
to be used to inter-calibrate instrument systems on both ships as well as some
other equipment took place shortly after the Gould had deployed their gangway onto an ice floe. Three investigators from the Gould walked several hundred meters across
the pack ice to the Palmer and came
aboard on the personnel carrier. The three stayed for about 30 to 40 minutes
before trekking back to the Gould. The Palmer
then made a large pond in the pack ice some distance away from the Gould in order to deploy the CTD for a
cast to characterize the hydrography of the
site. This cast was done by the Palmer instead of the Gould so that they did not have to cut a
hole in the ice outside their Baltic Room CTD hanger door immediately. BIOMAPER-II was deployed in that same pond to
make additional calibration measurements.
Finally, we got underway for the
start of the grid survey about 2030. As the Palmer
left the Gould's work site and
started back along the trackline toward station 76,
we took advantage of a large lead created by the passage of the ships earlier
in the day to do a 10-m MOCNESS tow followed by a live animal collection with
the Tucker trawl, which ended just after
During the day, a number of
marine mammals paid us a visit as described by Chico Viddi
below. A seal climbed up on to the ice pack shortly after the Palmer “parked” at the Gould work site in the early afternoon
and then slid back in and disappeared.
Minke whales were seen in the wake areas of both ships in the afternoon
and during the steam in the morning an Orca was also seen. During the
BIOMAPER-II calibration, five Crabeater seals came swimming into the open water
area where it was about to be deployed. They thrashed and frolicked around and
came up and snorted at us peering down on them from the fantail.
The weather as
usual was quite variable. In the late night (0045), the air temperature was -15ºC
and the barometer was 982.9 mb and rising as the low
pressure system passed through. Winds
were out of the west about 10-15 kts. Around 0700, the temperature has dropped to
-19.2ºC, the barometric pressure was a bit higher (985.5 mb),
and the winds were about the same. At
sunrise, around 1000, skies were overcast with the only clear sky at the
horizon. The sunrise was spectacular with brilliant reds and oranges giving
swirls in the clouds a scorched look. At mid-day, the skies cleared out
completely and the sun rose to
CTD Group report (Eileen
Hofmann, Baris Salihoglu,
Bob Beardsley, Chris MacKay,
Francisco (
After leaving the Gould on 11 August, the Palmer moved a short distance away to
make a hole in the ice for a CTD cast.
This cast was done in the vicinity of survey station 75. It provided a baseline for the first process
site as well as being the first survey station.
The CTD cast was to the bottom
(about 410 m) and 10 Niskin bottles were closed at
about 190 m to obtain water for Kendra Daly's group. The remainder of the Niskin bottles was distributed throughout the water column
to obtain vertical profiles of various properties.
The vertical temperature
distribution showed a homogeneous layer with a value of -1.8ºC that extended
from the surface to about 130 m. Salinity showed the same structure with a
value of 33.8. This is the thickest layer
of Winter Water encountered so far during NBP02-04 and suggests that there has
been extensive cooling at this location during the winter months.
Below the Winter Water layer, temperature and salinity increased to about 1.3ºC and 34.6, respectively, at the bottom. These values are characteristic of modified Circumpolar Deep Water. The bottom temperature at this location is 0.2 to 0.3ºC warmer than that observed during NBP02-02. Continued sampling along this transect and the one 40 km further south will allow us to determine the extent of the change in bottom water properties that has occurred in the past 8 weeks and perhaps how the change may have occurred.
Sea Birds (Chris Ribic and Erik Chapman)
Surveys were conducted for a
little over an hour on 11 August as the ship traveled from station 75 toward
station 76. Just a few small holes of
open water were present in the otherwise continuous ice-coverage. Three Minke Whales were observed off the port
side of the ship and Chico Viddi, the whale observer
on the ship, reported seeing at least 10 Minke Whales in this area. Birds were virtually absent from the transit
with just a single Antarctic Petrel recorded in the hour of observations. Seals also appeared to be in low density
today, as just 2 Crabeater Seals were observed.
Locations of the Adélie Penguins
fixed with satellite tags in
A summary of the birds and marine
mammals observed on 11 August (YD 223) during 1 hour 13 minutes of survey time
as the ship traveled south-east between stations 75 and 76 is the following:
|
Species (common
name) |
Species (scientific
name) |
Number observed |
|
Antarctic Petrel |
Thalassoica |
1 |
|
Crabeater Seal
|
Lobodon carcinophagus |
2 |
Marine Mammal report (
August 11 was the best day for
active marine mammal counting to date. This
day should be called "Minke Day" in honor of these wonderful creatures
(Balaenoptera acutorostrata)
that came out of the water and let themselves to be seen practically the whole
day. It was a wonderful day, starting with a marvelous sunrise followed by a
partially cloudy morning which turned to blue sky during the afternoon and
early evening. Air temperature was around -15ºC during the afternoon. Ice coverage
was 10/10 primarily first year ice of 70 and 90 cm thick. Weather conditions
were excellent, visibility could not have been better and the sun shining
brightly assisted us in sighting the whale blows. More than 10 different minke
whales were observed in 5 sightings. The first was made at 0901, 9º to port and
850 meters from the vessel (-68º 43.52′S; -76º 06.36′W). Two minke whales were observed spyhopping in a small crack in the ice. Five minutes later,
two minke whales were seen spyhoping in an ice crack
of about 6 m2, less than 50 meters from the starboard bow. Ten
minutes later another three minke whales were sighted at less than 300 meters
and 90º to starboard from the bow (-68º 44.14′S; -76º 05.54′W).
This sighting was particularly impressive since the three whales
spyhopped almost together in the same small 15 m2
opening in the ice pack. These three sightings may correspond to different whales, therefore the total count was 7 animals. Between the
second and third minke whale sightings, a great observation was made of an orca
(Orcinus orca) spyhopping
very close to the minke whales (Dickey Allison). Almost three hours later, at
1211, one minke whale was observed spyhoping three
times, again in a very small ice crack (-68º 41.6′S; 76º 10.36′W).
This sighting was made after the Gould
and Palmer had turned around and were steaming back to a location where the Gould would establish their one week
station. After this last sighting, only incidental observations were made
because the Palmer stopped to assist the
Gould with their set up. From 1300 to
1623, whales were observed spyhopping and surfacing
between 200 m and 2.7 nm from the vessel (-68º 40.35′S; 76º 11.04′W).
About 7 whales were counted in different groups. Blows were seen in a vast area
until the observation period was finished. An important event observed during
the second sighting was a whale with its mouth full of water, something that
happens when they are eating. This observation is correlated with the fact that
a dense patch of “something” (probably krill) was present in the water column
early this morning as detected by the ADCP (by Ryan Dorland). These dense concentrations
of potential food could explain in part the presence of whales and their high
activity in the area. Finally, it is important to mention that the ice coverage
and thickness observed today were not a constraint for the whales' activity.
The “perfect day” ended with a spectacular red and pink sunset and a new moon
on the clear sky.
Current Position and
Conditions
The survey of the southern sector
of the SO GLOBEC grid is underway and Palmer
is now steaming for station 80. Our current position at 0038 on 13 August is -68º
53.667′S; -75º 31.993′W. The ice pack is mostly 10/10 coverage and
we often have to back and ram to make forward progress. The air temperature is
-9.6ºC and the sea temperature is -1.863ºC.
The barometric pressure (996.1 mb) is holding
steady. Winds are out of the southwest
(217) at about 10-12 kt. The skies are overcast.
Cheers, Peter