Jan 12 - Krill and Table Tennis
Noon Position : lat 52 23.0 S, long 37 53.5 W
Air temperature @ noon today : 4.4 degrees C
Sea temperature @ noon today : 4.4 degrees C
Wind: Direction SW, Force 6-7
The week so far....
Well, I guess one word would sum up this week, and that word would be fog. Not that I have anything against fog.....actually yes I do! It spoils the view and makes the whole of the Southern ocean look the same, cold and dank. Despite the fog, the work on the Biosciences cruise has been going well and we have completed the majority of the transects. I am sure that those on night watch will be happy when we come to the end of this part of the cruise and move on to this year's second Western Core Box and our visit to Bird Island. In the meantime I shall keep an eye out of the window for a bit of sunshine.
Science bit in the middle - Krill olympics
Scientists know lots about the behaviour and ecology of birds and terrestrial mammals because they are generally easy to observe and identify; all you need is a pair of binoculars and some transport. Observing planktonic organisms in their natural environment is much more difficult, especially in the challenging realm of the Southern Ocean. Some observations can be made from deep-sea submersibles or using ROVs (remotely operated vehicles) but the disturbance they cause will inevitably affect the behaviour of the animals being examined.
Over the years scientists have learned a lot about distributions, mass movements and diets of planktonic organisms using a combination of sonar equipment and nets such as the RMT (Rectangular Mid-Water trawl). Over time these broad-brush approaches give a general picture of what is happening beneath the waves but can sometimes be misleading. A famous deep sea biologist once said that inferring anything about the ecology and biology of deep sea from trawls is akin to dangling an anchor from a hot-air balloon as it passes over a city and trying to understand the inhabitants from what gets caught on it. If the anchor caught an umbrella, a hamster cage and a pancake would you then assume that the city was inhabited by rodents that lived on pancakes and that it rained a lot?
In order to understand the incredibly complex biological web of interactions in the open ocean it is necessary to learn something about the individual organisms that inhabit it. Unfortunately when you take many of them out of their habitat and place them in aquaria they either die or are completely disorientated by surfaces and limitations on movement that they do not encounter in nature.
Geraint Tarling (BAS) and Magnus Johnson (University of Hull) have been working together on the James Clark Ross to try and understand some aspects of the behaviour of individual krill. By attaching krill to pendulums linked to a computer they have been able to record the swimming activity of individual krill and relate it to various aspects of their biology. As the krill swims it moves the pendulum and by knowing the weight of the krill and the pendulum it is possible using simple trigonometry to work out how much force the animal is generating. The traces recorded also allow examination of the activity patterns of krill and their response to changes in their habitat. On land this is all pretty straight forward......on a ship that moves with the waves things are a little more complicated. In order to work out how much the krill are moving a control (consisting of an average sized dead krill) is used to work out what the effect of the ships movement is. The method will be checked by comparing measurements of krill swimming on days when the ship is moving a lot and on days when it is at anchor in sheltered bays around South Georgia (and when might that be, then?!).
It is hoped that a better understanding of krill at the level of the individual will help those that are interested in the dynamics of the Southern Ocean at a broader level.
Krill biology by Magnus, thankyou.
Fun and Games
During the last week we have utilised the space in the cargo hold by getting out the table-tennis. A tournament has been organised and the first round is due to be finished in the next 24 hours. As a result there has been a flurry of ping-pong practise and challenges. It doesn't matter if you can only just hit the ball or you played at county level, everyone has been invited to join in. The initial matches should reveal those dark horses who look like they don't know one end of the 'paddle' (table-tennis bat) from the other, but are actually demon players. The reigning champion, Andy Hirst is on this cruise and we wait with bated breath to see if he can retain his title. Popular opinion is that the main challengers to his crown are Lee Jones and Nick Greenwood, JCR stewards. The betting (with chocolate money only!) has opened. Watch this space.
At the time of closing this edition of the diary we are in much the same situation as last week. Still sitting in the Scotia Sea in the fog. However, we have moved further north and there are breaks in the weather. On friday, 7th we had a stunning day with beautiful sunshine. The day was ideal for bird-watching and whale-watching. Those on the bridge and the monkey island reported many sitings, Southern Right Whale, Fin whale and Sperm whale, the latter showing his fluke before a dive only a few metres astern of the vessel as we were fishing. The birds have been numerous, the now familiar Black-Browed Albatross and Pintado Petrels predominate. There are also Wandering Albatross, Silver-Mantled Sooty Albatross, Grey-head Albatross and Prions as well as many others I can't even begin to identify. Andy Clarke and Mark Brandon are needed to help with the birding! It was a great relief to see the sunshine and the horizon, the day ended with a spectacular sunset and that is how I shall end this web-page. Until next week, good-bye!
All photos this week were taken by me, L Handcock