Feeling the pressure...

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I've been trying to write this last entry for a few days now, but we've been having real fun trying to get the internet! Something to do with the satellite being on the equator, and us being in the Arctic...

So we're over a week in to the cruise now, and everyone has settled in to somewhat of a routine. However, once in a while, something comes up that throws us all for a loop. A couple of days ago was my turn.

Part of my position here is to deploy sediment traps, and another is to run the experiment for primary productivity. This second one involves me getting up before sunrise and "spiking" samples with a radioactive carbon isotope. The samples then sit in an incubator for 24 hours
photosynthesising, and I get to filter them after that.

Arctic blog 2a.jpgPutting the samples in the deckboard incubator.

The idea is that we can use the C14 isotope to see how much carbon the phytoplankton are creating each day. Normally I get to do this experiment every other day - set it up one day, take it down the next. BUT! If we have to deploy our sediment traps, we MUST do a production experiment. That means that occasionally I double up, and a couple of days ago I had to do exactly that.


Arctic blog 2b.jpgRecovering the sediment trap array

Two productivity experiments and a sediment trap deployment and recovery meant that I only got 2 hours of sleep over a 42 hour block. Sleep deprived, I finally managed to take a break when we reached the first deep site of the cruise. This station, one of two that are greater than 2,500m took over 4 hours for us to profile with the CTD. It also meant that we could cover the CTD with styrofoam cups.

It's somewhat of a tradition that oceanographers have. One deep station per cruise is unofficially designated as a cup cast, where all the scientists on board decorate cups and tie them to the CTD. Now, styrofoam is mainly air, and as the pressure increases with depth, the air gets forced out of the foam and the cup reduces in size. This particular cast was to a depth 2,700m (8,900 feet, or about 1.8 miles). You can see from the picture below how much the cups shrink - they were both the same size before the cast! Just to give you an idea of the pressures involves, at the bottom of the cast, there is the equivalent pressure of 270
atmospheres, or over 4,000 pounds on each square inch!

Arctic blog 2c.jpgStyrofoam cups, before and after a trip to 2,700m

We've deployed traps again today, and they are due out tomorrow. Looks like I've got
another block of no sleep, so the bunk is looking very tempting right now. G'night

1 Comment

I think Beaker is afraid he's going to be sent down with the styrofoam cups.

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This page contains a single entry by jwhitefield published on June 29, 2010 3:38 PM.

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