2010 Expedition to Antarctica

Week 8

Monday - Wednesday, February 15 - 17

By Monday morning we made to Brialmont Cove in Hughes Bay on the western side of the Antarctic Peninsula. To start off science operations in the cove, we deployed a series of CTDs at the front of the Cayley Glacier, which is presently the largest tidewater system north of the Loubet Coast. The calving front (the section of the glacier that faces the water and discharges ice into the bay) is quite active. What makes the Cayley Glacial front unique is that it has maintained its calving position, whereas other tidewater systems have retreated along the northern Peninsula. CTDs along with a short term mooring will help us to evaluate what geological processes are occurring at the base of the glacial ice where the ice leaves the bedrock on which it rests and enters the water. This position of the glacier is referred to as the grounding line. Based on previous CTD casts in years past, we have determined that meltwater from the glacier is carrying sediment plumes into the water column, and additional CTD casts will allow us to study the diurnal (daily) or tidal controls on this process. We had hoped to examine similar processes at the front of the Crane and Hektoria Glaciers in the Larsen System.

Throughout Monday, we deployed a series of CTDs along a transect perpendicular to the Cayley Glacier calving front. The CTD results will be integrated with visual, time series photographs from the National Geographic time lapse camera that they installed on Alcock Island on Tuesday. While Debra Tillinger orchestrated the CTD casts from the Palmer on Monday, University of Houston undergraduate Yuribia Munoz and I performed a reconnaissance mission to two nearby islands and two exposed coastlines to scout out a suitable location for another GPS installation. Helicopter pilot Barry James transported us along with National Geographic photographer Sarah Park to Spring Point, Sprightly Island, Alcock Island, and Charles Point. The afternoon in the helicopter and on the surrounding pieces of exposed land was exhilarating. Munoz and I not only identified a potential location for a GPS installation on Charles Point, but we also observed a chipstrap penguin colony on Alcock Island and a scoua haven on Sprightly Island. Scouas are hearty, resilient birds of the Antarctic and are in the midst of hatching season. We ended the mission with a fly over the front of Cayley Glacier and made it back to the Palmer for dinner time.

We continued science operations into Monday night with a successful mega-core recovery from the inner basin Brialmont Cove. Tuesday, we also recovered of a 4-meter jumbo Kasten core from the middle basin. The core appears to have received a meter of sediment accumulation in the last 22 years, based on the last sediment core was retrieved from this area. The increase in sedimentation appears to be three-fold, although the frontal position of the glacier has not changed significantly during the same time period. We are interested in determining the source of such a sediment load and observing if the benthic communities have changes in response to the sediment load. During the night, we deployed another mega-core and yo-yo camera in the outer basin. Throughout the day on Wednesday, we deployed additional CTDs and recovered three mega-cores.

We hear from Ted Scambos and the glaciology team that they are now at SCAR inlet, where they installed their last AMIGOS. With their efforts combined with helicopter mission from the Palmer, we have installations at the following locations: 1. Robertson Island, bedrock cGPS , 2. Foyn Point, bedrock cGPS; 3. Leppard Glacier, p GPS, 4. SCAR inlet, p GPS, and 5. AMIGOS, Site Beta, Leppard, and Flask, SCAR inlet. During our time in Brialmont Cove, we are also assessing flying conditions for a mission to Cape Framnes on the eastern side of the Peninsula.

Wednesday - Friday, February 18 - 20

Wednesday was absolutely beautiful with the sun shinning high in the sky amidst a sky speckled with a few clouds. The pleasant weather afforded for a helicopter flight to Cape Framnes, where Dr. Eugene Domack and Dr. Amy Leventer installed our latest GPS station. Cape Framnes, where the two scientists were able to drop their equipment on Tuesday, is situated on Jason Peninsula in the Larsen B area. The installation of the GPS unit went well, and we are currently receiving signal from the unit.

While Dr. Domack and Dr. Leventer were working off Framnes Point, we deployed two zodiacs to accomplish four missions in cove waters surrounding the ship. One zodiac, carrying National Geographic photographers Maria Stenzel and Sarah Park among other passengers, motored to Alcock Island to retrieve a time lapse camera, where the National Geographic team had placed via helicopter two days prior. Two other zodiacs shuttled passengers to Spring Point to collected snow, glacial ice, and kelp samples. The last wave of the zodiacs took Lamont Doherty doctoral candidate Debra Tillinger, University of Houston undergraduate Yuribia Munoz, and other passengers in the surrounding waters to record the sound frequency of nearby ice bergs with hydrophones. The day off the ship was well received by all.

On Wednesday evening, the Belgian team completed a successful ROV dive of Brialmont Cove, identifying a collection of bivalves on the seafloor. On Thursday morning, we finished work in Brialmont Cove, after recovering a short term mooring under the supervision of Lamont Doherty oceanographer Bruce Huber. We also deployed an Otter trawl to sample the benthic organisms that dwell on the seafloor. The trawl brought up a range of interesting organisms, including more sea pigs, mollusks, three octopi, a variety of Antarctic fish, and crustaceans among other species. University of Hawaii post doctoral fellow Laura Grange worked into the evening preserving the specimens for future stable carbon isotope and genetic deconstruction work.

Thursday evening, we transited through the Gerlache Strait, deploying two CTDs en route, and as of Friday morning, we are now in Andvord Bay, where we will be conducting an extensive biological and oceanographic survey of the seafloor over the next forty-eight hours.

— Commentary and photos provided by Kimberly Roe '08