An Cosantóir the official magazine of the Irish Defence Forces and Reserve Defence Forces.
Issue link: https://digital.jmpublishing.ie/i/57282
30 | BY COMDT MARK BROWNEN Dive in Antarctica Part 2 C ontinuing on from last month's feature on Antarc- tica. While diving under ice there is quite a lot of noise, with floes moving against each other, ice cracking, and bergs moving in the currents, and you have to pay attention to these noises. The last dive of the trip was perhaps the most spectacular from this aspect. While dealing with an equipment failure, and ascending to the surface alongside an iceberg I became aware of very loud cracking noises. The base of the berg below starting to move up towards me: the iceberg had begun to topple over. The IA drill is to swim as fast as possible away from the rotation direction lest you get scooped up by the berg's rotation and caught in it. I swam away rather quickly as did the two German divers I was paired with and following the fastest exit we ever made from the water we were able to observe the rotation and col- lapse of the iceberg, caused by a second berg crashing into it, from the safety of the Zodiac. All nine other div- ers had also heard the noises and safely exited the wa- An Cosantóir March 2012 www.dfmagazine.ie ter or swam to a safe area. The iceberg was almost 40m deep, with approximately 20m above the water, and was initially thought to be beached in the inlet, which is why we chose it. However, we hadn't accounted for the speed that the current was moving and surrounding the bergs at, and it was one of these that collided with the berg we were diving on. Each dive (we completed 14) highlighted unique aspects of the environment and the wildlife of Antarc- tica. When diving in the Arctic north of Svalbard polar bears in the water were the threat but in the Antarctic the main threat comes from the leopard seal, the apex predator here. About 5m in length and weighing over 350lbs the leopard seal is a formidable sight to behold, particularly when encountered under water. It is aggres- sive, inquisitive and prone to investigating other crea- tures in its area, as one English scientist found out to her cost when attacked and killed by a leopard seal while carrying out underwater work at her research station.