of Terra NovaBay - the site of Mario Zucchelli Station
The Twin Otter being loaded on the ice at Mario Zucchelli Station
The flight was a microcosm of the International flavor of Antarctica: passengers on the flight included a French Geophysicist/Station Manager (his name was Jean-Francois) en route to the joint Italian/French Station (Concordia Station) at Dome C, and three members of the Italian Station, as well as the Pilot and co-pilot, and another Polish-Canadian pilot that was getting a ride back to Mario Zucchelli, plus myself, Joanna, and Graziano (the teacher from Italy). After the initial rush we waited for an hour while some bags were transferred from the C-17 that had just arrived from Christchurch.
Mario Zuchelli Station (formerly called Terra Nova Station) is the Italian station at the southern extent of Northern Victoria Land. We flew over the Ross Sea with views of the Transantarctic Mountains to the west (left) in the distance. But the view that captivated or mesmerized me was the view straight down. I had not realized both how complex and how distinctive the different types of sea ice are, and what a complex pattern they make - it was like looking at pieces of a jigsaw puzzle. At first much of the sea-ice was covered by relatively recent snow that was draped over the ice – one could make out subtle patterns in the ice below, such as the pattern left by the channel that was broken by the icebreaker when the ship came in last February/March. As we flow north we started to get a sense of the area representing a jigsaw of ice plates that been broken up, refrozen, then broken up again.
The Incredible World of Sea Ice
Here are some of the distinctive forms and features that I could see (go to the NSIDC or World Meteorological Organization or NOAA for descriptions and definitions of the different types of sea ice).
Ceramic Tile (my 'Trivet #1') showing winter and summer extent of sea ice around Antarctica - based on data and maps from NOAA)
We flew over the Drygalski Ice Tongue – which was the centre of an iceberg-related drama in 2005. The Drygalski Ice Tongue is the floating portion of the Davis Glacier. It is 20 km wide, 50-200 m thick, and at least 4000 years old (based on radiocarbon dates from penguin guano). The area of open water (polynya) on its northern margin provides access to good fishing for the penguin colonies in the vicinity.
View of edge of Drygalski Ice Tongue and adjacent sea ice (mostly Nilas Ice)
The Drygalski Ice Tongue is moving at a rate of between 50 and 900 meters per year. The iceberg-related drama that I mentioned is the collision of portions of the large iceberg (B-15) that broke off from the front of the Ross Ice Shelf in 2000 with the Drygalski Ice Tongue in April 2005. The chunk of Ice broken off the Ice Tongue measured about 7.5 miles across.
There are several areas of open water in the Ross Sea; these are called polynyas. The map below shows the approximate location of two of the larger polynyas we flew over.
The polynya near the Drygalski Ice Tongue is the result of strong catabatic winds that produce waves and prevent sea ice from forming. Within some of the polynyas that we flew over I could see incredible diatom blooms that look brownish grey in color; the distribution of the diatoms is a consequence in part of wind and wave action; diatoms are algae that make their microscopic shells out of silica - we have a team of diatomists working with Andrill that are using ancient diatoms to help us determine the age of the sediments in the core.
Aerial view of the Terra Nova Polynya with diatom blooms (brownish areas in the water). This picture is taken looking westward towards the Transantarctic Mountains.
Diatom Bloom at the edge of the Ice. Sometimes the thinner and younger Dark Nilas seems to incorporate diatoms from these blooms - it takes on a murky brownish color. There must be enough sunlight here to allow the diatoms to photosynthesize.
At Mario Zuchelli they had been very concerned as to whether the fragments of B-15 would collide with the Campbell Glacier Tongue, which is just north of the station, and essentially protects the water in Gerlache Inlet (the northern part of Terra Nova Bay) from early melt out.
This is important because at Mario Zucchelli they depend in part on a sea-ice runway as long as possible. It turned out that the Campbell Ice Tongue was unaffected by B-15, but Giuseppe and Roberto did describe the calving of a large portion of the Campbell Ice Tongue “we looked out the window at breakfast one morning and suddenly realized that the front of the ice stream had broken off and a large iceberg was floating away.” They are still waiting to see exactly how this will affect development and melting of the sea ice in Gerlache Inlet.
What amused me about my arrival at Mario Zuchelli was that even here in Antarctica, there was something about the color and light that made it seem Mediterranean (the wonderful pasta and good coffee also helped). It is situated on honey-colored granitic rocks in a small cove.
Mario Zucchelli Station with Mt. Browning & the Deep Freeze Range in the Background. You can see the sea ice runway (...on the sea ice ...)
The sun was low on the horizon, and the rocks had a warm glow to them, emphasizing their beautiful weathered shapes, illuminating the mostly blue and red station. It seemed like a picturesque fishing village in comparison to the enormous station at McMurdo.