Antarctica : A Journey Over and Under the Sea Ice

Join us in Antarctica as we drive across a frozen sea between huge icebergs to set up a diving camp

Why we had "stashed our cargo sleds"

Weather has the final say on how we do things down in Antarctica. We were planning to set off on the trip a couple of days earlier, but there was some particularly bad weather on it's way. We decided to get a start, and rather than enduring the storm in our tents we left the D6 bulldozer with the sleds and headed back to Scott Base in the much faster Hagglund. The image below has not been photoshopped and is representative of the "inside of a ping-pong ball" conditions we had on that day.

What I REALLY actually do in Antarctica

I work for Antarctica New Zealand as a field training instructor. This job does occasionally involve hard physical work such as moving large quantities of snow (as shown in the video), but it is generally characterized by providing training for scientists and providing safety support for their projects in the field. On this trip to Granite Harbour I was sharing the responsibility of assuring safe travel which involved choosing a route across the ice and identifying and measuring the cracks. I DO get to do some (relatively tame) kite skiing and snowmobiling, although the kiting/snowmobiling clips are not of me or even filmed in Antarctica.

Travelling across Antarctic sea ice

The ocean freezes over in McMurdo Sound Antarctica during winter and often breaks out by late summer. We did this trip in early summer (October) when the sea ice was still firm, cold and almost 2 meters thick (thick enough to safely land a Boeing 757 passenger jet). The map below is the shows the route from Scott Base to our destination at Granite Harbour. For some more aerial footage of the surrounding area, check out our page on the McMurdo Dry Valleys.

Cracks in the ice

One of the biggest hazards of driving over sea ice in Antarctica is large cracks caused by ice movement due to weather and ocean activity. The most dangerous of these are spreading cracks that widen and refreeze over time producing a crack with a profile shown in the diagram, that can then be hidden by snow. For the hagglund we can cross an effective crack width (W) of 75cm wide where the ice thickness is less than 70cm (T). The D6 bulldozer can cross a crack of up to 1.2m wide but we need a ice thickness of at least 1m on either side. These values are very conservative to enable a large margin of safety for operating in such an extreme and remote environment.

Camping in Antarctica

To ensure a successful 3 week antarctic diving expedition, life needs to be as comfortable as is reasonable. Divers need to be kept warm, hydrated, fed and well rested. Each team member has their own Scott polar tent complete with double Thermorest, sheepskin mat and -40 degree double sleeping bag system. The living/kitchen tent has a gas powered stove/oven, fireplace, and even AC/DC electricity supplied by the generator. Dive tents have electricity to run the science equipment, and gas heating to help the divers with the cold and also to keep the dive holes from refreezing.

How to pitch a tent on hard ice

During the sped up "setting up the dive camp" video scene I show a clip of drilling and tying a V-thread. This is an incredibly strong anchor that also has many mountaineering and ice climbing applications. It is made by drilling to intersecting holes in the ice to make a V shape that is then threaded with rope.

Making a dive hole

The most difficult aspect of making a dive hole in Antarctica is the fact that the ice is so thick (up to 2m). The first layers of ice can be cut through with a chainsaw, but eventually you need to puncture through to the water below and then have to somehow remove the ice at the bottom of the hole which is now completely submerged. To melt this ice into blocks we use a pump to suck sea water out of the hole, heat it up and then direct it back into the hole using metal tubing. In the time-lapse clip on the video you will see the tubing is first a square shape and then just a single bar. This arrangement melts the ice into blocks that float to the surface and can be removed.

SCUBA diving in Antarctica

SCUBA diving in such an extreme environment obviously has it's challenges. Firstly the water is a chilly -1.8 degrees C (28.8 F) which takes it's toll on the body and requires adequate systems and equipment to prevent hypothermia. Secondly the only place you can exit the water is the 2m square hole in the ice where you entered. This means that tethering divers with ropes, using good communication and having self sufficient rescue plans are vital to a safe and successful diving operation. All of the diving footage on the video is used with permission from Peter Marriot and NIWA. To see more of this footage and explanations of the science check out NIWA's videos Thin Ice and Ice Divers.

Antarctic science and global warming

Antarctica is the last region on earth to be discovered by humans. While being the coldest, driest and windiest continent it is also home to 61% of all the worlds fresh water locked up in it's ice cap. If it were to all melt this would represent a 58m rise in global sea levels. At least 30 different countries operate research stations on the continent and do so under guidance of the Antarctic Treaty. They study many things, but some of the most important studies relate to how global warming will affect both the ecosystem there, and the rate of ice loss and melting which will affect the entire planet. I support scientists by helping them directly in the field, but I also support them by sharing my images and experiences with you so that it may help you to appreciate what people are doing down in Antarctica and it's importance on a global scale.