Antarctic Diving – First Impressions

C-17 A Globemaster ‘chills’ out on the ice runway near McMurdo.

By Pete Notman. Images by Pete Notman unless otherwise credited.

My first trip to Antarctica was in 2008. My chance had come when one of the National Institute of Water and Atmospheric Research (NIWA) ‘team K082’ divers going to Granite Harbour that year couldn’t make it. After months of preparing gear for shipping down to Antarctica, double checking my dry suit and equipment (about five times), the time came to fly down to Christchurch. We were fitted out with our issue of Antarctic clothing in the afternoon and then the next day we headed due south on a C-17 A Globemaster. No frills on that military aircraft. There are only four functioning windows and the whole five-hour flight is rather like an arcade ride: lots of noise, lots of rumbling and without a window you don’t really know whether you are taxiing, flying or have arrived until they turn the engines off.

Not much more than ice and bare rocks topside in Antarctica, but underwater it is teeming with spectacular life moving in slow -2°C fashion. By Chazz Marriott.

Not much more than ice and bare rocks topside in Antarctica, but underwater it is teeming with spectacular life moving in slow -2°C fashion. By Chazz Marriott.

So I found myself at Scott Base on the great white southern continent looking down the barrel of an overnight stay in the icy wilderness as part of my field training and inductions.

I had done a little ‘pre-Antarctic’ conditioning by standing around in a -20°C walk-in freezer, but it wasn’t that comfortable really and everything that stays in a -20°C freezer for any length of time … freezes. There was a bit of pressure on me to pass field training. The mission to Granite Harbour pretty much involved me sleeping in a tent on sea ice at -20°C and diving twice a day. If I couldn’t handle the field training … it could be a loooong and unhappy six weeks ahead.

A first stage well iced up after a dive.

A first stage well iced up after a dive.

Fortunately I not only survived my field training initiation but enjoyed the experience of ‘chilling out on the ice’. My comfort was helped by being a warm-blooded mammal. The series of ice ages have equipped humans to handle cold surprisingly well (with the right clothes).

Surprisingly, Antarctica is very arid, being practically a desert despite all the snow and glaciers as far as you can see topside. OK, how come there is so much snow and so many glaciers? Well, they have accumulated over the millennia, which makes them all that more impressive.

Another thing acting in my favour was that we arrived towards the end of October, soon after the Antarctic sun stays above the horizon for 24 hours of daylight. The novelty of getting up at 2am in the Antarctic to check that it is actually daylight never wears off for me.

My first dive under Antarctic ice held a little trepidation. My build up had included dives in Bluff Harbour in winter (+8°C), followed by a full dress rehearsal ice diving course at Lake Alta, The Remarkables (+4°C), but Antarctic waters were still going to be a lot colder at almost -2°C.

The first dive was a no-task-loaded familiarisation dive, which was just as well because I managed to simultaneously experience most of the ’what-not-to-do’s’ when diving in the Antarctic. At least that way, I got rid of a lot of newbie bad habits in one go.

Experimental Microcosm chambers where pH and temperature were slightly modified to observe potential impacts of global warming on under-ice algae in Antarctic waters. Dive and safety holes shine like ‘beacons’. By Chazz Marriott.

Experimental Microcosm chambers where pH and temperature were slightly modified to observe potential impacts of global warming on under-ice algae in Antarctic waters. Dive and safety holes shine like ‘beacons’. By Chazz Marriott.

The dive went something like this: pre-dive checks (check); get in the water, dry suit dry, dry gloves dry (check); submerge through a hole in the 2m thick ice (check). Moment of WOW! because topside there is nothing but snow, rock and the occasional skua bird flapping very mournfully past (snacks must be few and far between for those guys), the occasional lost penguin (that should really be in a colony somewhere) and if you are lucky, you might see a few hauled out Weddell seals. In contrast, the seabed below the ice is swarming (in very slow -2°C fashion) with life and colour. Sea spiders, soft corals, tube worms, star fish, one metre-long nemertean worms, scallops, starfish, brittle stars and the occasional Weddell seal swimming past. It was awesome!

My habit of dropping towards the bottom as fast as possible, ending with a long burst of air into my buoyancy compensator resulting in a <<<Mission Impossible>>>-like hover above the bottom works well in warm ‘sharky waters’. However, this strategy doesn’t work in Antarctica for a number of reasons. One is there are no sharks and two, prolonged bursts of air into your buoyancy systems often freezes the button, which over-inflates your system and heads you back up towards the surface. Unhooking the inflator hose and frantic dumping of vents prevented a runaway ascent and a valuable lesson was learnt.

A diver completing a safety stop at the end of a dive. By Chazz Marriott.

A diver completing a safety stop at the end of a dive. By Chazz Marriott.

My next lesson was that you want to take things easy, keep your movements efficient and your breathing very controlled. I should have taken my cue from the Weddell seals that were swimming past. They are the epitome of breath-holding efficiency, but on that first dive, I was too excited to pay attention and breathed too hard on my reg, which started a ‘free flow’.

Fortunately, a free flow in -2°C is not necessarily a dramatic and life-threatening thing because it starts slowly with a little hiss of air dribbling out of the mouth piece. If you catch a free flow in the early stages, you can relax and slow your breathing right down and that little hissing stops. Otherwise, the hiss gets stronger and you have to shut down the reg, swap over to your back up and terminate the dive. With our diving times limited to a maximum of 40 minutes (or less if there are depth-related obligations), tasks have to be completed in a timely, but orderly fashion. So slowly and gently does it.

A crinoid and sponge at New Harbour 2009.

A crinoid and sponge at New Harbour 2009.

Antarctic underwater visibility is stunning and is really only limited by the amount of light that can get through 2m of solid sea ice (that is often covered with a layer of snow). Any break in the sea ice (dive holes for example) really stand out like beacons of light. Because we are tethered by a safety/communication line there was never any problem finding our way back to the dive hole.

Gear is pretty ‘techy’ with twin tanks, twin first stages, back up buoyancy options, and is run to a strict time schedule with time checks communicated at 15 minutes, 30 minutes and 35 minutes (time to come up). Good buoyancy control is vital to not disturb the animals and habitat in the areas where we work.

Safety is paramount and diving is very conservative. Although there is a well-equipped hospital and a chamber at McMurdo, evacuation to New Zealand as a result of any injury cannot be guaranteed because of weather and logistics.

Since that first trip I have been lucky enough to get down to Antarctica on four diving expeditions with team K082 and clocked up 78 spectacular, enjoyable and incident free dives.

Acknowledgments

Antarctic New Zealand’s logistics and Scott Base staff for getting us and a mountain of gear from New Zealand to Scott Base and then 150 nautical miles out into the wilderness. Acknowledgements also to NIWA, Royal Society of New Zealand Marsden Fund and the Ministry for Primary Industries.

The sea state for New Harbour was “Solid for as far as the eye could see”.

The sea state for New Harbour was “Solid for as far as the eye could see”.

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