Saturday, October 10, 2009

Close… but no cigars

Close, but no rum either! This was our clearest view, approx 12 nautical miles (22km) off the western-most coastline, of Cuba.

Happiness is a wet (and working!) CTD. We’ve carried out two 1000-meter test deployments on our transit South. Each of the numbered bottles goes down open with their spring loaded caps pulled back, top and bottom. At depth these springs are released, one bottle at a time, to collect seawater samples from whatever depths we want them.

Doug (left) and Sean drawing samples for dissolved methane analysis through the taps at the bottom of each CTD sampling bottle, following the first test deployment. A pair of spare syringes for taking methane samples can be seen, bottom left, resting on our all-important park bench.

Sean getting ready to do battle with his Gas Chromoatgraph. This is the instrument that we will use for all our shipboard methane measurements so getting practise in early is an important part of our preparations for when we get on station.

It’s big, its blue, and if it isn’t deeper than 3000m then it isn’t important. More than half our planet is covered by water of at least this depth – so how come so few people spend their lives studying it? There’s still so much more to be explored.
Position at 14h00 EST
Lat: 20° 16.3’N Long: 083° 39.1’W
Water depth: 4450m

Yesterday and today we have mostly been driving past Cuba. I think everybody on ship knows exactly what time we changed course and left the sheltered waters of the Florida Keys (2:30am Friday, thanks for asking) because that was the first time this trip when just staying in bed became something of a challenge! The higher you are in the ship, the more the swing, so the four of us in the upper cabins, along with the Captain and Chief Mate are the ones who notice this the most – and the absolute short straws go to James and Doug who are in the upper bunks in our cabins, above Andy & me, respectively.

Apart from pounding along through the waves, the other main “achievement” for the past two days has been to test out the CTD-rosette with all its new sensors to make sure everything is working properly. We had a first trial on Friday morning that went pretty well and then a second dip, also to 1000m water depth, right after lunch on Saturday. Not only has that given us the chance to “shake down” the electronics of the system completely, it has also given us the chance to flush through the water bottles with clean un-contaminated ocean water, far from land and collect first seawater samples for practicing our shipboard analyses with. As I’ve been writing this, Sean, Doug and Carla have been actively running analyses for dissolved methane – not only an important greenhouse gas but also a key diagnostic tracer of hydrothermal plumes in the deep ocean.

Yesterday was when we reached our point of closest approach, just a hair’s breadth over the 12 mile minimum necessary, rounding the Western end of Cuba (if you look closely you can just see mountains on the horizon). But today we are out in the wide blue yonder – and that’s a good place to be if you just spent two hours in your cabin working on your laptop and have made yourself queasy!

Too much information? Its an interesting point to remember – so don’t be surprised if you hear it more than once from me – that more than half our planet is covered by oceans more than 3000m deep (that’s about two miles down for those of you reading in old fashioned units). Perhaps that’s why there is still so much to explore.

Like I say, I’m sure I’ll return to this theme again in the weeks ahead but for now let’s end with a thought that turns Astrobiology on its head: if a civilization no more intelligent than ours were to send a probe from some other solar system to visit our planet, there’s at least a 50:50 chance that this is the kind of view they would first report back.

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