The Marine Team

Studying a unique marine environment such as the one around the West Antarctic Peninsula is best achieved by getting wet and underwater. I had quite a 'throwback' to my first diving experiences in the tropical waters of Tanzania which were a breeze in comparison to the level of preparation required to dive in Antarctica. In the tropics, it was easy to rapidly assemble our gear outside, sling it over our shoulder and walk a few hundred metres to a sandy beach where we would pile onto a small wooden boat. Diving operations in the polar regions are quite the contrary and are indeed a fascinating process. 

My first dives in Tanzania

First, the water temperature. Antarctica is a relatively thermally stable region, experiencing temperatures ranging from -1.8 °C in winter (the temperature at which salt water freezes) to heights of +2°C in the summer. I am amazed to learn about the first divers in Antarctic regions who braved the cold in 10mm rubber wetsuits. These hardcore adventurers would probably scoff at the level of protection we are equipped with today! The base layer resembles a padded sleeping bag and we wear these under our drysuits which we slip into via a back zip and are sealed in around our neck and wrists. With enclosed feet, no water can enter the suit. This leaves our heads and hands: an additional 7 mm neoprene hood and thick mittens are worn in addition to our suit which make us adopt a crab-like behaviour- essentially three fingers are grouped together whilst our index finger and thumb act as pincers. This claw-like style is a result of a trade-off between dexterity and warmth. Whilst our body layers are not restricted by their thickness, hand protection can only be so thick before collecting species or taking photographs becomes impossible!

My favourite British Antarctic training so far has been the dive familiarisation week. With water temperatures of 16°C around Southampton, it was not quite representative of the conditions we are about the face. Nevertheless, we practised many useful skills with this year's Marine Team. First up were line signals. Before entering the water, a diver will always be tethered to the surface with a life line for a measure of safety and to guide the diver back to the ice hole in winter. Another level of precaution is having constant communication between the diver and 'topside' (the dive supervisor). This is achieved using a communication system in which, by talking into a small microphone that is fitted into our full face masks, we can report our progress whilst topside monitors our breathing. However, communication can sometimes fail if ice were to obstruct the signal or if the electronics were to take the day off. Therefore, having a reliable means of communication, by using a series of line signals, is an essential backup. For example, 4 pulls on the rope tells a diver to surface safely, 3 bells is to direct the diver right whilst 4 bells tells the diver to move left (relative to the orientation of their lifeline).

Another great endeavour was diving with a DSLR camera in underwater housing (Nikon D7300) affixed with two strobes. Simon Morley (an Ecophysiologist at BAS) accompanied us on the dives and guided us to some freshwater sponges and zebra mussels. These still subjects were great to practise angling the strobes and obtaining sharp images. With this nailed, we could progress to photographing some inquisitive pike. During the next dive, I practised photographing with the manual setting, adjusting the aperture and shutter speed according to the depth of field of my subject and light availability. 

 

To get used to doing fiddly activities underwater, and with gloves, we raced in pairs and were challenged with building a 3D rectangle from 8 bars of varying length and 24 nuts and bolts. Topside was regularly checking our progress and air supply so we had to be alert on all fronts and manage to not become too task focused. The final result was spectacular....

 

Moving from fresh water to salt water, the RIB (rigid inflatable boat) was deployed into the Hamble estuary on one of our training days. The aim of the exercise was to execute diving operations by kitting up on the confined space of the boat, entering the water (by spectacularly rolling back off the side of the boat) and de-kitting in the water. The sandy, muddy bottom of the estuary was a delight and home to many scurrying shore crabs darting between locks of fine red seaweeds. The bottom was littered with slipper limpets, anemones, sponges and sea squirts. We also took the opportunity to practise some rescue missions in the event of an unconscious diver. 

Our final challenge was to shackle and then mouse (securing the pin so that it does not rattle) chains together in a specific arrangement. This task was to be completed in nil visibility which was achieved by sticking a layer of grease-proof paper into our masks. The timer stopped once we had built the structure and sent it to the surface using a lift bag... it was however not so easy to distinguish between the opening and the top when blind.

A rest was well deserved at the end of the week!

  

As I write this, I am still yet to be deployed to Antarctica. Two weeks of quarantine is one the horizon before we set sail....