Antarctic Expedition 2009
March 6 - April 15, 2009
Northwestern Weddell Sea
The RVIB Nathaniel B. Palmer arrived in Punta Arenas late last night and docked behind the ARSV Laurence M. Gould, the other ship in the United States Antarctic Program.
This map shows the ship's track during the 40-day expedition in
the Weddell Sea.
We came within our first sight of land late this afternoon as the ship approached Isla de los Estados at the southeastern edge of Argentina.
We are now nearly one-third of the way across the Drake Passage, the notoriously rough waterway that connects the southeastern Pacific Ocean to the southwestern Atlantic Ocean.
As the Palmer began heading north this morning on its journey back to Punta Arenas, the science teams began the time-consuming process of packing up samples, instruments, and lab supplies.
What does an iceberg look like underwater? ROV IceCUBE has recorded
several hours of video footage underneath the icebergs being studied in
this expedition, and has uncovered surfaces with pockmarks, linear
crevices, caves, and jutting spires.
The last water collections and science activities finished in “Iceberg
Alley” this afternoon.
In anticipation of favorable weather, the UAV team prepared a plane with a new housing for the GPS drop tag.
We travelled northeast through the night to return to the site where a Lagrangian sediment trap (LST) was deployed three days ago.
Today we had a memorable encounter with a small pod of whales. Three humpbacks cavorted near the ship just after lunchtime.
Onlookers gathered on the bow to watch as a Zodiac boat was lowered into the water.
The search was on for an iceberg that could be
studied with ROV IceCUBE.
Bottles and bottles of seawater samples were processed in the research
labs today.
Today was the final day at iceberg C-18A and researchers pushed to collect their last samples before leaving. ROV IceCUBE completed two biology dives for the Robison lab, one in the morning and one in the afternoon.
In a light swirling snow, the MOCNESS nets were brought back onto the ship before sunrise this morning. The catch was noticeably different than the night before in both species diversity and overall abundance.
Science activities filled the day and every group busied themselves with sample collection and processing. After an early morning deployment of the shallow towfish, ROV IceCUBE was readied to conduct a biology dive...
High winds and waves made the seas too rough for most science equipment to be deployed last night. The science schedule was adjusted and the time was used to complete another surface mapping survey.
Stormy seas with winds gusting more than 45 knots curtailed science operations this morning. As the ship rocked and rolled, the zooplankton team sorted net samples from the late-night tow of the MOCNESS system.
The chemistry group—Tim Shaw, Cole Hexel, and Scott Kindelberger—has
been quietly taking samples and providing behind-the-scenes support for
many of the research groups involved in this study.
The icebergs and growlers that we passed today have been many shapes,
sizes, and color variations. White, blue, green, and streaks of brown
make each one unique.
Yesterday evening, the principal investigators analyzed measurements
around iceberg B-15L to determine if it could be the next study site.
Late last night they decided to move on to another iceberg
Today we arrived at iceberg B-15L, a long, tabular iceberg similar to C-18A in appearance and size (28km long by 12km wide). We began by circumnavigating around the iceberg to assess its shape and the direction of its drift.
Through the night, the ship completed a final surface mapping of iceberg C-18A, returning to the same area where measurements first took place at the beginning of the study.
Today ended up being our last day near iceberg C-18A. Though the weather improved considerably from the night before, satellites show a large storm system moving toward us within the next 24 hours.
To better characterize the influence of the iceberg on surrounding waters, sampling has been divided into near and far stations. Surface mapping early in the study of iceberg C-18A established a background of typical open ocean parameters, such as temperature and salinity, to help the science team determine these sampling stations.
After a day of searching, researchers found and recovered the Lagrangian sediment sampler that collected samples from under Iceberg C18a.
The wind increased considerably today but in the lee of the iceberg, the
seas were still relatively calm, allowing sampling activities to
continue throughout the day.
For a brief few hours today the weather looked favorable for flying the UAV aircraft to drop GPS tags on the iceberg. The seas were smooth and winds had lessened to only a few knots in the lee of the berg, but it was the sun—or lack of it—that interfered.
A bleary-eyed MOCNESS team recovered nets again at o’dark-thirty this morning and spent the day sorting through krill, salps, and other denizens of the midwater.
Well before the sun came up this morning, Ron Kaufmann’s team assembled on the back deck to recover the MOCNESS 10m2 net system that had been towed behind the ship for the past six hours.
Early this morning, the engineering team (Alana Sherman, Paul McGill & Ken Smith) sent a Lagrangian sediment trap (LST) under a smaller iceberg that was about 16 km away from C-18A.
The surface mapping project continued through the night and into the early evening today as the ship followed a grid pattern around the iceberg. This pattern is referred to as “mowing the lawn”
We continued our course to iceberg C18a today. At the daily science
meeting, the principal investigators planned their equipment deployment
and sampling for the first days around the iceberg.
The ship stayed near the Frei field station last night but moved out of
the harbor at Maxwell Bay on our way back to Iceberg C18a.
Today our science sampling went on hold as we made a medical detour for one
of the ship’s personnel. The Antarctic region is extremely remote and the
ship is prepared with trained medical technicians, supplies, and a link to
doctors on shore that can be consulted when issues arise.
This morning began sunny and bright at a location
several miles away from C18a, where the CTD was used to collect
seawater samples. Ben Twining’s group also deployed gear in
this area, testing special trace metal clean water bottles. 
Iceberg! Around 10 pm last night, we gathered on the bridge in excitement as the ship approached iceberg C18a. The iceberg was a bright red line on the ship’s radar but the wispy fog obscured the powerful spotlights sweeping into the night.
Just after noon we reached Clarence Island and moved to the east side in what we hoped would be the lee from the westerly wind. Dark jagged peaks covered in ice were hidden in a froth of white clouds.
Since we can’t simply just drive around the ocean to find an iceberg to
study, how do we figure out where to go?
The ship passed around Cape Horn today and began the crossing of the Drake
Passage. The temperature has been dropping as we head south. The water near
Tierra del Fuego this morning was 9°C and air temperature 21°C (70°F). After the last lines were thrown off the dock, the RVIB Nathaniel B. Palmer left the
Punta Arenas port and began its transit across the Straits of Magellan to
the Argentine coast and into the South Atlantic Ocean. |
