Feb 10 - A Little Bit Of Science
Noon Position - Lat: 54° 00.1' S Long: 038° 06.0' W
Location - Off South Georgia
Total Distance Travelled: 17971Nm from Immingham, UK
Air Temp: 4.3°C
Sea Temp: 3.9°C
Clicking on most photographs will enlarge them.
A Little Bit Of Science.
Just where has the last month gone apart from a blur of scientific research? You find us today off the coast of South Georgia starting some of the logistic tasks we need to complete before heading back to Stanley in the Falkland Islands. We were scheduled to pickup the Bird Island team next Wednesday, but the weather forecast doesn't look good and so we've brought them out a couple of days early as we'd hate to leave them behind. Our calls into South Georgia also mark the end to the majority of the JR177 science programmes. They will windup now and start the long process of packing and storing all those closely guarded samples for return to the UK. The scientists will then spend the coming months ahead working on and analysing the data that they produce.
It has been a long cruise with the ship having steamed nearly six thousand miles by the time we see Stanley again. The drawing below gives you a feel of the voyage taken with the yellow line representing the cruise tract up until yesterday.
The cruise has been looking at the ecosystem of this particular area of the world with everyone having their own areas of special interest. With twenty six onboard this allows the whole spectrum of interests to be covered from the chemistry and neutriants found in the seawater itself, which in turn feeds the simplest forms of life. These in turn provide food for other animals and so up it goes through the food chain to the largest predictors i.e. the penguins, seals, whales and other sea birds found in this area of the world. The central item in this picture is the humble Krill and Sophie Fielding explains below how this very useful animal is to be found, tracked and caught to allow their life cycle to be more full understood.
Target Fishing For Krill
The hunt is on! We are searching for one of the most abundant animals in the Southern Ocean - Antarctic krill. Krill are small crustaceans – a bit like prawns you would buy at the fishmongers. They live for up to 6 years and are around 4-5 cm in length when adult. They feed on phytoplankton (algae that are equivalent to ‘grass of the sea’) and are themselves a key food item to many Southern Ocean higher predators such as fish, penguins, seals and whales.
Surprisingly, given that these animals are so abundant (approximately 500 million tonnes in biomass – roughly equivalent to the biomass of the entire human race), we are presently struggling to find them!
We use a scientific echosounder to search for krill and other pelagic animals. The echosounder works by sending out sound waves from transducers mounted on the bottom of the ship and then listening for echoes (backscatter). How long these echoes take to come back and how strong they are indicates what is down there and where it is. There could be krill, fish or smaller creatures such as copepods and amphipods (other types of small crustaceans). Krill are particularly noticeable because they form swarms, which appear as areas of intense backscatter. Once found, we turn the ship round and deploy a net (a Rectangular Midwater Trawl or RMT) to the depth at which the swarm was seen. The RMT can open and close on command, and we only fish it briefly so that we collect just a small number of animals in good condition.
If the hunt is successful, orange krill monsters (alias Angus and Ted, krill ecologists wearing warm padded boiler suits) emerge from the cold room at a run. They scoop up the krill in a bucket and return to their lair to study krill behaviour and feeding habits. All that they leave behind are orange blurs and, in Angus’ case, a pair of blue gloves.
Krill are hitting the headlines as their vulnerability to rapid climate changes in this part of the world are becoming ever more apparent. A collapse in the krill stocks will devastate populations of penguins, seals and whales. Our research will work out how these animals respond to present day environmental variability. In turn, this will help us understand how they will cope with any future rapid changes.
Thanks to Jon Watkins, Sophie Fielding and Jose Xavier for the photgraphs this week.
The End Is Nigh...
Soon Stanley will be just over the horizon and as well as the end of the cruise it will also mark the end of Captain Champman and his crews period onboard. Immingham at the end of September does seem a long time ago, so we're off to put our feet up if we're lucky. Though if the rest of the team are anything like me there will be a few jobs to do first repairing all those things that have broken at home over the last five months. Captain Burgan and his team will be entertaining you for the rest of this Antarctic season. Then before you know it the end of May will be upon us and we'll be back in harness for the refit and a bit of science way up north. Until then I'll take my leave and say goodbye from all onboard. For our final image of the trip I''ll leave you as we began, but this time with a sunset from down here.