A day in the field: Under the ice with Rod Budd

Diving under two metres of Antarctic ice in water that’s –2 °C: this is Rod Budd’s idea of fun. Getting to do it for work is just the icing on the cake (so to speak). For the past seven years, Rod has helped out with IceCUBE, NIWA’s benthic marine biodiversity programme in the Ross Sea (see Update from IceCUBE). Back at his desk in Hamilton, Rod hits the highlights of this exotic field work.

What’s your window for fieldwork out on the ice?

October–November is the summer field season, with November being right at the edge of reasonable conditions. Any warmer and the ice begins to break up – it's much easier to work through solid sea ice than work from boats and have to deal with floating ice and icebergs.

My role as Antarctic Dive Supervisor begins back in Hamilton. I assemble all the dive gear and ship it to arrive in Antarctica about a month before the field team. The challenge is to get all the essentials – including any spare parts – into a space constrained by the effort and expense of shipping to the Antarctic.

Do you have to use specialist gear?

We use the same gear as for diving regular waters, only more so. The drysuits include gloves and the hood has to seal to the mask. And the insulation under the drysuit is thicker than usual. For safety’s sake, we wear two tanks and two regulators. The commonest problem is for a regulator valve to freeze open; if that happens the diver must switch immediately to the second regulator and then return to the surface.

We enter the water through a 1200-mm hole in the ice, which is about the only source of light, especially if there’s snow on the ice. For safety, another hole is made within 50 m, just in case a Weddell seal takes a fancy to the hole you’re using!

Sounds like safety is an over-riding concern.

That's right. Another precaution is using six people to cover a two-person dive. That’s one supervisor, one standby diver in full gear, ready to enter the water, two divers in the water, and two line-tenders (the divers are tethered to the surface at all times, both for safety and for communication with topside). These roles get shared around, and no individual ever dives more than twice in a day.

What are your living conditions in the field?

Our campsite has two large insulated and heated ‘Polar Haven’ tents, one dedicated to dive gear and the other for the lab, instruments, and mess. For sleeping, we each have our own tent, uninsulated but windproof. These are small enough so that your body heat quickly raises the temperature inside to a comfy minus 15 degrees. By November, you’re in 24-hour daylight. Air temperatures this past season were mild, ranging from minus 5 to minus 15 in the ‘daytime’, but dropping to about minus 30 when the sun was lower in the sky and the field site was shadowed by a glacier.

So what would you do in a typical day in the field?

0730 - Get up, moving kind of slow because you’re still knackered from the day before. Cook breakfast – as a group effort – on a two-burner Coleman stove.

0900 - Prepare for the day’s dives: reassemble your personal dive kit from the day before; organise sample and core containers. Three divers suit up (this takes longer than usual because of the extra thick suits and heavy tanks). Check tank pressure and update dive log sheet.

1200 - First diver goes into the water, pausing for a while in the hole until the diver and the supervisor are sure there are no leaks in the drysuit and regulators, then down through two metres of ice and out of the way for the second diver, who also pauses for a check. For each new hole, I’m the first diver in so I can be sure everything’s okay for the rest of the team.

On the first dive at a site, we lay out two 25-metre transects by pegging large white measuring tapes to the seabed, and then we shoot a video along each transect. The divers begin collecting samples of animals from the seabed, putting them in large plastic tubes for safe transit to the surface.

Typically, we’ll find starfish, urchins, a bivalve similar to a geoduck, and pastel-coloured worms two metres long. We see smallish fish, about 30 centimetres long, but we don’t collect them for this project. Weddell seals feed in these waters and sometimes come around just to see what the divers are up to. Up on the ice, there are occasional visits from Adélie penguins: they seem to think they’ve discovered a camp of other penguins.

1300 - Both divers are out of the water and out of their gear, and everyone tucks into lunch. When you’re diving in these conditions, it’s almost impossible to over-eat, and we eat huge helpings of chocolate, cheese and crackers, rice or pasta, and usually some sort of one-pot meal made with frozen meat.

1500 - After lunch, the biologists begin working up the samples, and the divers prepare for the second dive of the day. This time they take cores from the seabed to record the sediment structure and to sample the smaller animals that live in the upper layers of the sediment. In the third dive at a site, the divers complete any coring, retrieve the transect lines, and fill any remaining time underwater with video and still photography.

1700 - Out of the water for the day and time to tend to the gear, top up tanks for the next day, and do general camp maintenance, including collecting more ice to melt for drinking water and cooking.

2100 - Dinner at last, a similar meal to lunch, heavy on the kilojoules, with perhaps some dessert and wine.

0000 - Bedtime. With the full daylight, we tend to stay up late, preparing gear for the next day, attending to personal interests. Going to sleep may require some sort of sleep mask or a cap pulled over your eyes.

Your enthusiasm for the task shines through.

Diving is what it’s all about – wherever I go in the world, I always want to see what’s under the water, and in the Antarctic the contrast is so amazing. Up above, out on the ice where we’re working, there’s hardly anything – no plants and just the odd Adélie. But under the ice there’s heaps of life and all sorts of things going on. And diving in the Antarctic – in such an extreme environment – presents an interesting logistical challenge: you have to be prepared with back-up gear and redundant systems or else you risk ruining an extremely expensive research effort … or worse.