21 January 2002 - Stromness.....oh yes!!
Position at 1200: 53° 53.2'S, 34° 30.1'W - About 65NM East Northeast of King Edward Point
Distance Travelled since Grimsby: 27251 Nautical Miles
Air temperature: 4.8°C; Sea temperature: 3.7°C
Oceanweather.com allows you to see all the weather reporting ships and their position. The position
is marked by the vessels call sign so to see where RRS James Clark Ross
is you are looking for ZDLP on the map. If you want to see our Sister-ship
RRS Ernest Shackleton you are looking for ZDLS1.
Click on the South Atlantic area of the map, and choose "Marine Observations"
The weather blew up over the last week to the extent that we were forced to ‘heave to’ (stop the ship and point into the wind) for a while until it calmed down a bit. The main reason for this is because we were doing acoustic survey transects towing the UOR and using the EK500 echo sounder. When the ship is rolling around a lot these do not work very well and so you do not get any data. Also the ship has to slow down. Apart from the fact that the large swell makes it quite uncomfortable at times, the ice becomes very hard to spot. After sitting this out overnight in amongst a lot of icebergs it was decided to bring forward the visit to Stromness to calibrate the echo sounders and other acoustic equipment, this had originally been scheduled for next week but as ever we have to be a bit flexible. The image here shows the bow burying itself into the large swell. Click on the image for a better view.
This is also a good opportunity for people to go ashore and stretch their legs after being on board for a while, and for the crew to get in some boat training. Most people on board took the chance to go and so this week we have some good wildlife photos courtesy of Sarah the Doctor, to break the monotony of the science and ship ones, which is always welcome!
Above: King Penguin (top left), Gentoo Penguin (top right), a Penguin Rookery (bottom left) and a South Georgia Reindeer (bottom right). Click on any image to enlarge it.
While the people were ashore, we on the ship took the chance to launch both of our life boats as well as our rescue boat and a RIB. The fairly un-subtle remarks from some of the scientific staff as we were taking them ashore about ‘boys and their toys’ didn’t go unnoticed we can tell you!
A short history lesson about why we study the sea around South Georgia, By Pete Ward – Principal Scientist
BAS oceanographic research around South Georgia has been ongoing for almost 25 years and has its antecedents in the pioneering work carried out during the Discovery expeditions of the late 1920’s and early 1930’s and again in the early 1950s’. These expeditions had their roots in the concern that the rapid development of the whaling industry in the Falklands Dependencies would prove short-lived and it was considered necessary to attempt to understand the underlying biology of the whales, and the waters into which they migrated to during the Antarctic summer. Thus it was economic motivation that underpinned subsequent work on whales and their principal food, the Antarctic krill. The cost of these investigations was borne by revenues raised from the whaling industry.
Work published by the Discovery committee in an extensive series of reports forms the basis of much of what we know about the basic ecology of the Southern Ocean and although timely, it wasn’t in itself sufficient to prevent the ultimate collapse of the whaling industry.
A resurgence of interest in the Southern Ocean began in the 1970s with the recognition that as traditional fisheries resources were dwindling, attention was turning to alternatives such as the Antarctic krill. International scientific committees recommended that more effort be put into oceanographic research on krill and other resource species and for its part, BAS instigated an oceanographic research programme known as the Offshore Biological Programme (OBP), whose main field of operation was to become South Georgia. This productive part of the Southern Ocean, with its vast concentrations of krill eating predators such as seals and penguins is likely to be particularly sensitive to any changes in krill abundance brought about either by fisheries operations or by fundamental changes in ocean currents mediated by global change.
For the past twenty or so years, as well as engaging in international research programmes, we have been running a series of cruises around South Georgia, which have been aimed at gaining a wider understanding of how the local ecosystem functions and how it links out into the wider Southern Ocean. Because krill do not reproduce around the island but are brought in on the ocean currents from further south and west, it is important for us to link variability in krill abundance around the island to changes happening elsewhere in the Southern Ocean. In a way this brings us right up to date because this is very much the focus of our current cruise (JR70) in which we are working to establish the pathways and flux of krill and other zooplankton into and within the region. Our approach is certainly technologically different from the Discovery days. We now have a sophisticated modern research ship instead of a refitted sailing ship perhaps better known for being the one used by Scott on his first expedition south.
Computers, satellite imagery and much of the other equipment we routinely make use of were unknown in the 1930’s when notebooks and pencils, microscopes and steam driven winches were more the order of the day. Some things however would have struck a chord but for all that our research owes a great debt of gratitude to those early pioneers and we are in many ways still standing on the shoulders of giants.
(Ed's note.... Some photo's that go with this piece, also fit in nicely with next weeks page, so due to the amount of photos this week, they will be posted next week.)
And some of that research involves....Physics!
The Oceanography - Physics team consists of Mike Meredith, Sally Thorpe, Jon Watkins, Alex Tate and Nathan Cunningham. Mike has written a piece for us on what they are up to....
Frequent readers of this esteemed column will know already that one of the major aims of this year’s big biology cruise to South Georgia is to work out a budget for krill in a box to the northwest of the island. For historical reasons, this region tends to get called the Western Core Box. To calculate a budget for krill requires information on a number of factors, such as how much krill enter the box, growth of krill within the box, how much gets eaten, and how much leaves the box. To do this calculation properly requires information on the physics of the ocean. "Why so?" you ask.... well, its a generally-accepted fact that krill live in the sea, so the speed and direction they travel in depends not only on how fast they swim (which is often not very fast at all), but also how fast the water they live in decides to carry them. And that’s where we come in.
There are two fundamental methods for measuring ocean currents:
(1) put something unattached in the water and see where it goes
(2) put something attached in the water and see how fast the water moves past it.
This year, we’re doing both.....
Preliminary results from the first method are shown here - these are the tracks from drifters that were deployed at the start of the cruise. Basically they just follow the currents and report their positions at regular intervals, from which current speed and direction can be calculated. The drifters transmit their data to satellites, from where it is transferred to France, downloaded to BAS HQ in Cambridge, and emailed back to the ship for us, courtesy of Andy Wood and his souped-up computer programs.
These drifters are designed to last for a year or more, and so have only really just begun their lives, but already they are showing some interesting features. It's pretty clear that the water over the deep ocean to the north of South Georgia is going at a fair old lick to the west, while the water over the shallower ocean closer to the island is much more confused about what it wants to do. The small-scale loopiness of the tracks is due to inertial currents – basically the effects of variable winds and the Earth’s rotation. The drifters that have reached the farthest west seem to be turning around and getting ready to come back to the east. This is to be expected – the Southern Ocean has a general west-to-east flow, it is only strange places like the northern edge of South Georgia where this is reversed. Notice that one of the drifters deployed at the eastern edge of the box seems to have got this idea much quicker than the others, and is already hurtling off in an eastward direction – what does this one know that the others don’t?
The other method for measuring currents that we are using this year is one that we have used many times in the past. We stop the ship, and lower over the side an instrument that records the temperature and salinity of the water from the surface to just above the seabed. From this data (plus other measurements made on the ship itself), we can calculate the water flow past the instrument. The data for this have been collected, but need a great deal of processing and analysis before current speeds can be derived. However, you can see some of the data brought vividly to life in this stunning 3D visualisation, courtesy of Alex "SFX" Tate.
So, work continues apace, with more drifters soon to be released from captivity back into the wild, and more instruments being lowered over the side. All that will be left then is the months of calculations needed to come up with an answer....!
Rogues gallery....the physics team
The Birthday Boys of the week.....
This last week saw the birthdays of two of the people on board, Steve Mee our Radio Officer and Doug Bone, BAS resident net designer/builder/repairer.....etc etc. They were the lucky recipients of a visit from a beautiful lady.....'Matt...ilda' during Sunday's pub lunch.
First many thanks to all the contributors this week, Pete Ward for the history lesson, Mike Meredith and the physics team and Alex Tate and Sarah Hortop for photos, and last but not least, Matt for finally showing his true colours, he is already taking bookings for future events. What a star!!!
Coming up we look forward to finishing the current CTD transect and moving back along to the Western Core Box, with some target fishing on the way and next week.......bongo nets and little sea beasts!