Report 11: Time out (or in)

The underside of the Aurora in dry dock showing the echosounder transducers
The underside of the Aurora in dry dock showing the echosounder transducers
Minicosm tank before krill added - water is cloudyClear water four hours after krill addition

Steve Nicol, Voyage Leader

Excitement is rising on the Aurora as we head down Transect 7 towards Mawson. Station visits are a much welcome break for most aboard on these long science trips, but for some they are the period when the most intensive work is carried out. One of the main reasons we are visiting Mawson is to calibrate the ship's echosounders; they work rather capriciously in cold water and the instrument readings tend to drift, so we need to moor up in a location where the ship can be held firm in deepish water and run them through a series of tests. The acoustics team then suspend small metal balls beneath the ship (I'm not making this up) at different points in the echosounder beam and relate the signal they detect to the known depth and position. Even less believably, this precision operation is facilitated by the use of servo-operated fishing rods, which move the balls around at Toby's whim and, failing any major upsets, this operation takes around 36 hours during which sleep-deprived acousticians become progressively less calibrated as the instruments become more so.

Unfortunately, upsets can include ship movement – and the katabatic winds at Mawson are notorious for their strength and ship-moving ability so the work has to be factored in around the weather. Meanwhile the majority of those aboard will be welcoming the first opportunity to put their feet on dry land in nearly six weeks and the prospect of seeing old friends and new faces. There is also the attraction of the first open bar since we left Fremantle some 4,500 nautical miles ago. There are 84 people aboard the Aurora, which is about three times the number of people at Mawson so it promises to be a rather overwhelming experience for the station-dwellers. The station personnel are also mostly men so it will be a great relief for most of the blokes on board to have a chance to sit down with other blokes and have good blokey conversations after having to put up with the company of so many women on the ship – and we feel sure that the chaps at the station will feel the same way.

Scientifically, things have progressed well with little drama to report and the data continuing to pour in, much to Bec's delight. The oceanographers got a bit excited the other day when they thought they had found something they didn't expect but then Nathan assured them that they had in fact expected it and he made them do another CTD as a punishment for imagining that the ocean was not entirely predictable from models. The krill remain enigmatic and are refusing to toe the party line on where they should be found, and what they are allowed to do on the odd occasion when they are found. In fact, both shifts have been having difficulty finding sufficient krill to populate the Hilton as the nets bring up organisms that the acoustics claim do not exist, rather than the krill that we all need, want and love. All is not lost on the krill front, as So and Toshi appear to have demonstrated that female krill, like females of so many other species, relish each other's company and reproduce far better in a maternity wing than in the normal hotel suites where they can be pestered by males.

Up on the swaying superstructure the whale observers continue to amaze by being able to identify black spots using a highly definitive classification scheme which includes terms such as: "like minke", "possible humpbacks", "not dissimilar from fin whale" or "I'm buggered if I know but let's call it a blue whale". The seabird observers are a great deal more scientific in their approach and counted no less than 720 wandering albatrosses on Tuesday after a lone wanderer lapped the ship once a minute all day – Adrian and Andrew were so dizzy afterwards that they had to lie down and be shown obscure rock videos for an hour or two before they could resume their vigil. Meanwhile the phytoplankton squad are gleeful having discovered a new way to purify in the water their minicosm tanks – just add krill and stir – the unfortunate by-product is, however, an Augean stable of krill poo to remove at the end of each Herculean experiment.