Following my recent introduction to boating, earlier this month I was able to join the dive team for one of their regular trips.
Marine biology and oceanography make up a major slice of the science conducted at Rothera, with the dive store backing onto the Bonner Lab. The Bonner provides decent bench space for three dry labs, one wet lab, and also houses a cold water aquarium for specimens - looking at the newly collected “beasties” is a popular attraction for folk on base.
In addition to having one of the longest running CTD datasets in the world, extending back several decades, other research highlights for the dive team include a heated-plates experiment – observing species migration as plates laid on the seafloor are heated 1ºC above ambient temperatures – and ongoing assessment of the scouring effect of icebergs on the seabed.
Dan, the incoming diving officer for this season was due to take his first Antarctic dive with Pete, his outgoing equivalent. The dive team and doctors enjoy a close working relationship, as the doctor is often recruited for seal-watch1 and with a hyperbaric chamber onsite, both medics and divers train regularly together.
Supporting the divers is a topside crew: Ash, the summer boatman and marine biologist, was behind the helm for this trip, with Mairi, another marine biologist, assisting the divers.
After winching the boat into the water, some 10m below Biscoe Wharf and clambering down a rope ladder into the boat, we shoved off and motored gently round to the south of Rothera point. After having their final pre-dive checks with Mairi, Pete and Dan rolled backwards into the water and made their way back to the wharf underwater.
With the water being a frosty -1.5ºC, the divers wear thick drysuits, mitts and hoods with full face-masks, complete with an underwater comms system, which helps the divers communicate with each other and also the topside crew on the boat. Bottom time is as much limited by the cold as it is by air supply or no decompression limits, with dives rarely exceeding an hour in duration. BAS maintains a conservative safety margins with all diving: no mixed gases, no decompression and divers are attached to a safety line.
Despite these sensible limits, Antarctic diving seems to be a breath-taking experience (if you’ll forgive the expression), as evidenced by the footage from the divers’ GoPro cameras - hopefully the subject of a future post.