LARISSA - LARsen Ice Shelf System, Antarctica, a NSF-funded project.

LARISSA - LARsen Ice Shelf System, Antarctica, a NSF-funded project.
We are conducting an integrated, multi-disciplinary field program to address the rapid and fundamental changes occurring in the Antarctic Peninsula region as a consequence of the abrupt collapse of the Larsen B Ice Shelf in the fall of 2002. A profound transformation in ecosystem structure and function is occurring in coastal waters of the western Weddell Sea. This transformation appears to be yielding a redistribution of energy flow between chemoautotrophic and photosynthetic production, and to be causing the rapid demise of the extraordinary seep ecosystem discovered beneath the ice shelf, providing an ideal opportunity to test fundamental paradigms in ecosystem evolution.

Wednesday, March 21, 2012

Thursday, Mar 15th Finally in Antarctica! Our first station is in the Antarctic Sound, a strait at the tip of the Antarctic Peninsula. The working day for the science started early this morning; the first rosette with Niskin bottles and the CTD (conductivity, temperature and depth profiler) was in the water before sunrise to collect water samples to investigate the properties of the water column, such as nutrients, and to look at the pelagic microbes.

Laura and Jackie taking water samples from the Niskin bottles

Unfortunately, we were unable to recover the whale-bone lander yet due to some issues with the gear and poor weather. The thick fog that is engulfing the ship offers very little visibility to spot the lander once it rises from the seafloor to the ocean surface, so the principal investigators chose to postpone this operation until later in the cruise. The extreme climate of Antarctica produces fascinating ecosystems, but also often makes our oceanography sampling very challenging.

As we headed further south, the fog dissipated in the afternoon and we spotted the first iceberg of the cruise, and then many more! We are now sailing through the real polar ocean, with ice floes and icebergs everywhere! We watched Adelie penguins running over the ice floes and sliding on their bellies to run away from us; Minke whales inspecting the waters around the icebergs and skillfully navigating in between them; crabeater seals and the fur seals resting on the ice! What an experience on our first day in the Antarctic!

Adelie penguins on an ice floe

Crabeater seal

Jackie enjoying the view of the icebergs

Our second planned station is the Vega Drift, a rapidly accumulating drift of sediment on the eastern side of the Antarctic Peninsula, near Vega Island. The Vega “drift” is formed by current focusing, and is rich with organic matter (yummy to sediment microbes) and and layered sediments (good for reconstructing geological history). We will use a Kasten core to take a sample of sediment up to 6 m long and to give us insights into past processes and environmental conditions in the Antartic Peninsula area over the last 3000 - 5000 y.

Scientists getting ready to take samples of the sediments from the 6-meters long Kasten core (Photo A. Lancaster)

Map of the cruise track starting in Punta Arenas, Chile (at the upper part of the image) and ending on the eastern side of the Antarctic Peninsula (at the lower part of the image) where we are now.

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