07 January 2001 - Science Around South Georgia
RRS James Clark Ross Diary
Noon Position : 53 degrees 41 ' South. 36 degrees 19 ' West.
Distance travelled since Grimsby: 16,163 nautical miles
Air temperature @ noon: 3.7 degrees Celsius
Sea temperature @ noon: 3.6 degrees Celsius
BACK AND FORTH TO SOUTH GEORGIA
After the excesses of Christmas and New Year the last week has been
pretty quiet, apart from, of course, the continuation of the science programme.
We have continued the transects that take us back and forth towards South
Georgia, so we see land daily, but we just can't get to it! To the left is the view
we get most days of the spectacular mountain scenery.
We have had the good fortune of some truly balmy weather for a couple
of days, during which you could almost forget where you were, although
the nippy wind tends to brings you back to reality pretty quickly, not to
mention the odd iceberg drifting by. Apart from the views of South Georgia
we've had a constant supply of seals and penguins swimming alongside the
ship - the whales have remained ellusive as usual, although apparently
there have been sightings.
As this cruise comes to a close it is also time for the crew change over and so everyone is busy with the necessary jobs for a smooth handover to the next team, who are expected in Stanley in just under two weeks time. Next week's webpage will therefore be the last one from RRS James Clark Ross with Captain Burgan's crew,and also probably my last attempt as editor as I hand over the mantle to the two experienced professionals - Dave and Simon. More on this next week.
SOME SCIENCE...........................
You may not actually know where we are doing all this science so here is a map to
show you where South Georgia is.
The map below left shows you where we planned to go, and the one on the right shows you the track we actually went along. It's not bad really, although there are a few deviations for bad weather and ice.
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Planned cruise track. |
Actual cruise track. |
Right, so, onto a bit more detail, following on from last week.(We honestly tried not to make this too dull, but we are beakers* so we tend to get carried away,so our apologies. Just look at the pictures instead if it's too boring).
(*see glossary - ed.)
First a bit of ecology..................
Krill are at the hub of the food web in the Southern Ocean. They eat
phytoplankton and are themselves eaten by whales, seals and many different
sorts of seabirds including penguins (but not Polar Bears). Krill
are also hunted by fishermen. Because they are so important to the ecosystem,
we need to know how much krill there is, especially at South Georgia where there
are huge breeding colonies of seals and penguins (but not Polar Bears).
When there are low numbers of krill those animals dependent on them for
food can fail to rear their young and the species on which the krill feed
go into overdrive.
Krill TV
We count krill using
an echosounder mounted in the hull of the ship. It transmits short bursts
of sound into the water every 2.5 seconds and measures the volume of the
echo. The "louder" it is the more krill there are beneath the ship.
By adding up all the echoes along our 80 km survey transects we can work
out the number of krill along each transect. The picture on the left is
from the echosounder monitor.
This year to the west of South Georgia we have detected about 480,000
tonnes of krill, about 84 times the weight of RRS James Clark Ross without personnel and
cargo. This is quite a high value (sometimes it may be as little
as 60,000 tonnes) and the penguins and seals breeding on the island seem
to be doing okay. If the krill population persists at this
level the polar bears may get wind of the easy pickings and migrate down
here!!??!!
A crucial part of understanding
how and why the animals in the oceans do what they do is knowing about
the place they live in. As you already know from last week's page,
there is aboard a dedicated team of water babies, sampling, measuring and testing
the environment favoured by the beasties, every time the ship stops
moving, i.e. at a station, which it does on a regular basis. Counting the krill is done as the ship is moving and so we need
some way of measuring conditions without stopping the ship. To do this
we use a thing called the Undulating Oceanographic Recorder, aka
"beauty", "baby", "darlin", "beast", "brick", "damn thing" etc etc depending
on how well (or not) it is behaving. It’s an oceanographer with
a bunch of recording instruments in their pocket, attached to a bit of
string, that we throw over the back of the ship (still attached of course)
and pull along behind us while Andy and company use their echosounder. The UOR
uses a propeller and fin to move up and down in the water in a zig zag
so we can create a picture of what is in the water to compare with the
picture that the krill people get.
Krill swim to the surface at night because they can feed with less danger of being eaten by predators that rely on their eyesight - and hence daylight - to find them. However, because the echosounder is below the surface it can’t detect the krill and so we do all the transects during the day. We do two back to back, starting at 5 am and finishing at 2 pm (local time). Each one is 80 km long and the UOR and echosounder collect information from depths between 6 m and 250 m. Once this is over and it has become dark we head off to the station and the "netting bods" get into their gear to try and catch some of the things the echosounder saw.
Right science over.............
We’ve only got thirty days, 21 scientists and 29 officers and crew to do
all this, so as you can imagine there’s a pretty hectic schedule to keep
to and so there are people working 24 hours a day, both to do science and
to keep the ship running. We’ve included a few snapshots of the people
you might find lurking around during the night who keep the show on the
road as it were. Science never sleeps!
Glossary.. to be taken with a pinch of salt!
- 1: "Beaker"
- Slang term for scientist. Mildly derogatory, and therefore often employed by the crew (humph). Derives from geeky character in the Muppet Show.
- 2: "Transect"
- Essentially a straight line drawn on a chart
along which you wish to carry out your continuous experiment. There are
however a few finer points to consider when at sea. Firstly you have to
choose your transect so that it is perpendicular to the direction of the
prevailing waves which are BIG in the Antarctic. This will cause the ship
to roll like a pig and prevent you from sleeping for more than two minutes
in a go. It also serves to make sure that normally horizontal surfaces
are kept as close to vertical for as long as possible. Thus helping to
keep desks free of unnecessary clutter like books, pens, computers, coffee
cups, hairbrushes and beer cans.
If your experiment involves towing something behind you then you must also make sure that you carry out your transect over the least well charted area of sea bed. Preferably maximising the number of places where the chart says inadequate surveys or "Here be dragons". Your transect must also be located to encounter the most icebergs possible so as to reduce the total length of time actually spent sailing on the transect to a minimum, and prevent the actual cruise track from looking anything like your straight line or in fact being where you'd planned it to be in the first place. - 3: "Station"
- A specific geographic location in the sea where you wish to carry out your experiment or take your sample. The first principle here is to define your position accurately. 16 decimal places is the usual precision but more is always a bonus and infact some random number generators can produce infinite accuracy, so by all means convey this figure to the navigating officer. Don't worry about the format of this number s/he will always require something different. Because of the precision required for station work it is customary for the scientist in charge to check the global positioning system (GPS) regulary when manouvering onto station. Should the values drift by more than the 16th decimal place, it will be necessary to inform the navigating officer to make sure he puts the ship on exactly the spot you require. Under no circumstances must the ship be allowed to move vertically or horizontally whilst sampling. But if it does don't worry, if you record only the positon at the start then that means you didn't move, so that's okay. On the subject of icebergs it is important to note that your station position will almost always be within a mile of one and generally downstream of it. You will therefore almost never sample the point that you originally planned to stop at.
The funny bit (apparently)..........
Some findings so far:
The Southern Ocean is very, very cold.
Sigma Plot can draw some very pretty but very confusing maps.
Initial findings indicate that penguins do not in fact, live in plastic wrappers, dress in them for special occasions or have a prediliction for primary colours. After this positive start to our initial research, we feel that we might be able to crack the elusive penguin plain/milk chocolate dichotomy.
Elephant seals stink, burp and fart for a living (good work if you can get it).
All the polar bears have gone north for a bit of a boozy skiing holiday.
Petrels don’t run on petrol.
Fur seals need to book themselves in for an aggression management course.
You can’t rush research Mate!
And finally............ The Krill Witch Project
Just a quick hello
from all of us here, to Geoff Cripps, a long standing member of the biosciences
division who unfortunately can't be with us this year.
No I really mean finally...........
Can anyone tell our
data manager what the little triangles are on the wing of the Tri-star?
As the editor can't stand another flight with him asking.
Okay this is really it...............
A few words for those of you left behind this Christmas and New Year by crew and scientists. Thank you for your patience, we’ll be back soon Tri-star and the RAF willing.
Palindrome of the week.
Go hang a salami, I'm a lasagna hog
"and your family."
P.S. Happy Birthday to the third Mate Neil Macleod - 25 and loving it.
