Tuesday, May 5, 2015

Sampling

Over and over, we sample.  The equatorial transect was the most intense - 4 - 5 stations a day, sometimes with only an hour of CTD time out of the water.  We have been exhaling a bit as our stations get further and further apart.  One of the crew began comparing us to zombies who crave sea water.  "Must sample.....need seawater.... "

The repetition goes something like this.  The crew navigates us into position, the CTD is deployed, it goes down to the bottom and back up firing bottles and taking measurements along the way.  The CTD is recovered, and the bottles are sampled (see videos below).  We sample in a certain order to assure the best data possible. Gases sample first because once the bottle is open, a head space opens up in the bottle, and the water in the bottle can exchange with that air.  Then come the carbon measurements that are sensitive to gas exchange, and finally those that aren't gas-sensitive, like organics, nutrients, and salts, go last.  All the while, the sampling zombies are calling out their numbers and the sample cop ( in this video, that's me) is keeping order.  The stations where we sample during the sunrise are my personal favorite.

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You might notice everyone has their own tube to sample from the niskin's spigot.  The end that goes on the spigot usually has some type of zip tie arranged on it to identify that end. Folks get a little creative with it and each tube has it own character.  Of course, so does each sampler!

Then, when the sampling is finished... we have to get ready to do it all again.  Empty the bottles, and then prepare them to go in the water.  You can see Jim, our survey technician on the Ron Brown, doing just that in this video. Go Jim go!

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