2010 Expedition to Antarctica

Week 4

Monday-Tuesday, January 18-19, 2010

Amidst the slight rain and low cloud cover, we have spent the last two days in a majestic fjord called Andvord Bay, which is fed by at least a half dozen glaciers. A glance at the coast shows how the glaciers are flowing off the crumbling mountainside and into the water, but what we can't see with the naked eye is how the glaciers are releasing fresh water and reworked sediment into the water. Understanding these processes is one aspect of the purpose of our Andvord Bay survey. We have cast numerous CTDs to show us what is happening in the water column as well as deployed the yo-yo camera to learn about the biological activity in the bay. Switching out the yo-yo camera for our own point and click cameras, we got an opportunity to see biological activity right at the water surface on Monday night around midnight. With the sun still hanging in the sky as if it were mid afternoon rather than the twilight hour, a party of over eight hump back whales breached the surface to say hello. The waters in the bay are quite protected and productive, bringing the whales in to feed on krill that in turn feed on phytoplankton, which can grow rapidly with sunlight due to the current absence of sea ice. Yesterday, a party of four scientists, documented by the National Geographic team and aided by two Raytheon marine technicians, went out on the zodiacs to sample the phytoplankton. We tied three nets, each with a different pore size, to the back of the zodiacs and drove several transects to collect a suite of phytoplankton. Each of the scientists, including Duke University graduate student David Honig, Scripps graduate student Mattias Cape and his mentor Maria Vernet, and myself, will take splits of the catch and collaborate on the analyses that each of us will run at our home laboratories. The advantage of participating in the Larissa project is the opportunity to work with scientists within and outside our own disciplines to understand a particular system. At this point in the cruise, our attention is turned to understanding the oceanographic, biological, and geological workings of Andvord Bay. Another way at achieving our goal is by use of the ROV. Over the past few days, Katrien Heirman, Dries Boone, and Lieven Naudts have been readying "Suzee" for a swim, and last night we lowered the ROV into the water for a dive that lasted through the early morning hours. The team has set-up "Suzee TV" for us to see what she is seeing on TVs throughout the ship, and we all watched along as Suzee came across a benthic community that varies from what we saw in Flandres Bay, according to David Honig's first glance of the footage. Over the 5-hour dive, highlights include an octopus sighting and the collection of a handful of tube worms, a starfish, and krill. All were excited for a successful deployment and for the opportunity to use Suzee again.

Wednesday - Thursday, January 20 - 21, 2010

Yesterday evening and into the early morning hours of today, we halted our geological and biological survey of Andvord Bay. During the day, the weather was clear, allowing a short helicopter flight to Duthier's Point, where Dr. Eugene Domack and Dr. Amy Leventer identified glacial as well as marine sediments, and Dr. Greg Balco and graduate student Debra Tillinger scrambled on the rocky cliffs to collect rocks for exposure dating. The trip proved successful in both scientific objectives and penguin sightings. Later in the evening around 11 pm, we deployed our first mega core, which is a device that collects 12 separate sediment cores. We outfitted the already impressive coring apparatus with an underwater camera that allows us to decide where to release the core. With the efforts of the Captain and his crew, we can position our equipment quite well, but in reality, deploying a device from the ship to the seafloor is a bit like dangling a 1000 lb piece of equipment from a skyscraper. The camera gives us extra flexibility in choosing our coring sites and is extremely important when we are targeting specific benthic habitats. For example, in the Larsen System, we will be targeting the methane cold seep for both geological and biological analyses, and we would like to collect cores from the cold seep. Last night, we were excited with the success of the camera and the mega core itself, recovering eight of the 12 sediment cores. Several scientists claimed the cores for a suite of different analyses. Hamilton College professor Mike McCormick selected two cores for microbial analyses, and Dr. Craig Smith, post doctoral fellow Laura Grange, and graduate student David Honig used several cores to document macrofauna living in the sediment, and Dr. Scott Ishamn examine one core for foraminfera. Everyone out on deck got a sneak peak of one the macrofauna species as the cores came out of the water. Because the plastic tubes that hold the sediment cores are clear, we could all see a few unfortunate krill that got caught in the water above the sediment.

Just after the mega core made it out of the water, we prepared to collect another jumbo Kasten core from Paradise Harbor. The core came out of the water during the twilight hours at a length of 113 cm. After deploying countless CTD casts and yo-yo cameras and two telling sediment cores, we have decided to transit south to Barilari Bay, where we can commence a biological and geological survey of this fjord and send off the glaciologists to perform their work on the eastern side of the peninsula via helicopter.

Friday - Sunday, January 22 - 24, 2010

Friday morning brought us into Barilari Bay. A quick look outside at the surrounding waters was enough to show some differences between this fjord and the last, Andvord Bay. More bergy bits and ice bergs are floating alongside the ship in this area, and the waters are less productive and less salty. The system receives a high sediment load from the surrounding glacial system, which includes at least six main glaciers. To put data behind our preliminary observations, we deployed yo-yo cameras, CTDs, and the ROV as well as collected a 1.3 m Kasten core, which contained mainly terrigenous sandy-clay sediments. We also performed an extensive survey of the seafloor topography, what we call bathymetry, which is the first time this has been done for Barilari Bay. While we are all eager to learn about the geology, oceanography, and biology of an unchartered fjord system, we were all relieved when Saturday morning brought blindingly sunny weather. The window of clear conditions was ideal for flying a team of four glaciologists (Terry Haran, Ted Scambos, Ronald Ross, and Erin Pettit) to Site Beta, the Larissa ice camp, where a team led by Ellen Mosley-Thompson is drilling a 400-meter ice core. See pictures of the ice camp, taken by Raytheon Marine Projects Coordinator Adam Jenkins.

The glaciology group aims to install in-situ devices referred to as AMIGOS (Automated Meteorology-Ice-Geophysics Observation Stations), which include ice GPS units, thermistor strings (temperature recording device), and digital cameras for time-elapsed footage to monitor glaciers that feed the Larsen System. The glaciology team also aims to conduct seismic surveys of the ice. Their work will complement the geologic, biologic, and oceanographic work that we hope to conduct in the Larsen System, when we return to the eastern side of the Peninsula in February.

— Commentary and photos provided by Kimberly Roe '08