We finally arrived at Rothera Research Station last week. Another stage of my journey over, and another begins. Actually before we docked was the last serious science for me on the trip. I have had some equipment sitting on the seabed off Rothera for the last two years measuring the temperature, salinity and ocean currents as part of my climate research. One of the really special things about this bit of kit is, we also had a couple of sediment traps down there as well. Now a sediment trap is just like a huge yellow funnel about 90 cm across that catches the debris that falls through the ocean down to the sea floor (we call this marine snow). This snow is always falling in the sea, but in this part of the world it is a bit more interesting because lots of algae grows both in and on the bottom of the sea ice. So when that stuff melts and the algae falls out you get a kind of blizzard falling to the sea floor. What makes the sediment traps really good is on the bottom of the big yellow funnel is a computer controlled sample unit that swaps a sample bottle at the bottom of the funnel every couple of weeks – and that means you get a time series of how much of this snow falls through the year. And of course we put this together with the ocean current data and can try to understand the regional link between climate and biological activity here.

I said the kit has been on the sea floor for a couple of years – but that is not strictly true because every year we have visited and recovered it from the sea floor to download the data, then redeployed it again. But the fact that you have got it back before doesnt mean it is any easier to get this time....

The whole point of this sort of science is you can leave the stuff and it works through the whole winter when you are not around. But out of sight is definately not out of mind. I have woken up loads of times over the last year dreaming of icebergs running the kit over and destroying it.

So it's now about 14 months after the last time I deployed this bit of kit and I am close to where we dropped the kit off.

We stop and lower our hydrophone (a big waterproof microphone) and shout "hello" (an acoustic signal at a special frequency that tells the kit to answer us).

Silence.

"HELLO".

Silence.

My heart starts to sink and I have a mental picture of the iceberg that must have destroyed the kit. It's one of those moments you plan for but hope won't come. But it has. OK, option A doesn't work, try option B, then onto option C, D and so on.

By 15 minutes I was up to option F and still no answer. Then I heard a tremendous WHOOOSH. A couple of Minke whales were on the surface next to the ship and breathing. I guess they had probably heard our hydrophones and come to investigate. I didn't have time to look but they did distract the people not involved in the science from watching me struggle.

I was pretty tense by option K when finally we got an answer. It was still there and on the sea floor! But was it OK? It took another 20 minutes of struggling before I thought we had finally persauded it to come to the surface.

I turned to the bosun to tell him, and was just in time to see him point, smile and say "there it is Mark".

My large orange float was about 100m from the ship.

In the open ocean with kit floating on the surface it can sometimes be a bit tough getting it on board, but with this ship, this crew and in calm waters I knew the job is done.

It's hard to describe the relief. But it was soon followed by the most amazing tiredness. I have had a couple of months of nightwatches now and I guess every day you are a little more burned out.

As soon as the kit was on board that was me in bed. It was the end of my last night shift of this trip.

When I woke six hours later we were alongside at Rothera.

Although I haven't talked about anyone else on the ship, of course I am not alone! One of the ironies of working in Antarctica is that most people imagine you are going to be lonely. The reality is that most people work either on bases or research ships, and the real problem is that you are in close proximity to people all the time. Consequently to get on in this environment you need to be really relaxed and calm. Now forty or so people with relaxed attitudes doesn't make for good Big Brother type television. We don't argue, shout at each other or anything like that, we just get the job done. And of course if you have gone to the trouble of being away from home and leaving your family and friends, then you may as well try and enjoy yourself to make it easier.

Now personally I can't remember how many times I have been south but its probably about 20 times in total (so far!), and that means I have a certain view of the things I am seeing and experiencing. I thought it would be in interesting for you to read how people can feel on their first visit to work in Antarctica. Luckily there are three other scientists keeping blogs on this trip and all of them are well worth a visit (if only because they are all better photographers than me!).

First there are two PhD students from the University of East Anglia - Geli, and Karel. Geli is German and has written her blog in two languages, and Karel is Mexican so you need Spanish to read the text - but can enjoy the brilliant photos. And finally there is Dr Paul, a research scientist at BAS. Enjoy!

Now we are back into the satellite footprint and able to read the news I find I have missed a terrible Channel 4 TV program that apparently didn't bear any resemblence to reality and was about global warming being a "swindle". It must have been truly terrible because apart from the usual suspects you would expect to criticize a program like that such as The Guardian, The Independent and the excellent www site realclimate.org - the British Antarctic Survey - a UK Government Research Lab has issued a statement saying in very polite language that Channel 4 should be ashamed.

With so many climate scientists on the ship we have talked a lot about ethics and honesty and what we are doing studying the climate. My take is that as a scientist you only really have your integrity and without honesty a scientist is nothing.

I find it dissapointing because my University has gone to great lengths with the BBC to make high quality award winning TV programmes about climate change and why we should act. Whilst I doubt the program makers care about what they have done - they really really should.

Last nights blizzard has got worse during the day and at the moment we are holding our position in a big sea and strong winds waiting to make more measurements. It's not so confortable with the ship rolling about 15 degrees either side of vertical and it doesnt make sleeping easy, but it should be over in a day or two.

First the Good news

Friday morning 0114 my time, 0515 UK time and we are in position to make a crucial set of measurements across the George VI Sound. Once we have completed this we should be able to work out how much the entire 25000 km² George VI ice shelf is melting. What makes this really neat is that other scientists have measured it in the past and worked out it's melting between 3 to 5 m a year. Now any previous measurement in Antarctica is a rarity I can tell you, so once we work the current melt rate, we can deduce whether the ice shelf is decaying more rapidly or slowing down. If the ice shelf melt is increasing then of course we could point the finger at human driven climate change, and ultimately, I guess, our results help our government decide on how to tax us by reducing our CO₂ emissions.

But I have just realised I haven’t said actually how we measure if the ice shelves are melting. The principle is easy – you measure the temperature and the amount of salt in the water that flows under the ice shelf, then measure the temperature and amount of salt in the water that flows out. They should be the same if the ice shelf isn’t melting – so any difference we see is caused by melt water from the ice. If you think of it another way, if you have a glass of gin of known alcohol strength, throw in some ice and let it melt, if you measure the alcohol content when you come back you can work out exactly how much ice diluted your alcohol. It's just on a bigger scale, and without the gin.....

Deploying a CTD.

[Image by Mark Brandon, © copyright Mark Brandon]

That’s the principle, but in practice you have to be super accurate which is not so easy in -20°C. To measure the temperature and salinity of the water flowing under the ice shelf our ship first has to break a hole in the ice for us, then we lower a piece of equipment called a CTD over the side of the ship all the way down to the sea floor. Its called a CTD because it measures Conductivity (that is the amount of salt), Temperature and its Depth. Now CTDs are pretty expensive – the one we are using costs about the same as a brand new Ferrari, and we lower it through the ice on a small cable about 1cm in diameter sometimes down to 3000 m, and get to within about 4 m of the sea floor. If it touches the sea floor – that’s very very bad – we could lose it. But at the same time we want to get as close to the bottom as possible so we measure all the water beneath the ship.

And all the time the ship is being bashed around by the sea ice. Its OK work when the Sun is out, and it’s the middle of the day, but as I type this it's dark again and we are in ice almost 4 m thick and being menaced by a couple of icebergs that can't decide which direction to drift in. I don’t sit here worrying about the cost of the kit – but I have to be pretty responsible about the risks I take.

By the time my 12 hours watch is up I am ready for a break.

More good news

The ship has a strange and unfamiliar smell…. Soap powder! Big thanks to the engineers - they have managed to make enough water to open the laundry again.

And the bad news...........

Say it quickly so it doesn’t hurt so much.

This part of Antarctica has run out of chocolate.

I am in shock.