A Float Between Islands

The ship's bosun and his mates stand ready to lower Pixel off the stern of the ship.

Yesterday we deployed another float, our second of the six planned for this cruise. Adopted by Stanford Online High School in California, the float is named Pixel, after the school's mascot.

Pixel was deployed at 06:00 local time, which right now is the same as GMT (Greenwich Mean Time, also referred to as Zulu time). We crossed the zero (also called prime) meridian a few days ago and are now in the West longitudes instead of East. It was still dark out, so not quite as photogenic of an operation as the one from last week, but it went smoothly and that's the important part.

We deployed Pixel during our transit between the islands of Tristan de Cunha and Gough, and it should provide some interesting data. The South Atlantic Subtropical Front crosses through this passage, separating two very different water masses from each other. Oceanographers are able to tell the origin of water throughout the world's ocean using many of the properties collected by these floats, including salinity, pH, nitrate, and dissolved oxygen.

The hope is that Pixel will drift back and forth across the boundary a few times, profiling the water column on each side. It would be great to see plots from this float providing a direct comparison of the tropical-influenced water mass on the north side and the polar-influenced waters on the south.

As I mentioned in a previous post, the scientist studying rockhopper penguins can see the difference in the population that lives on either side of this front as the different water masses support different prey species. She got off on Nightingale Island yesterday, and I will make sure to ask her more questions when the ship picks her up again in a few weeks.

Thankfully Pixel is a simple mascot, so didn't ask too much of my limited artistic skills. 

Pixel is just the latest float to be deployed for the SOCCOM project. Also underway right now is the GO-SHIP P6 cruise, crossing the Southern Pacific Ocean from Sydney, Australia to Valparaiso, Chile. They are also conducting CTD casts and deploying floats, with names like Floaty McFloatface and Magic School Bus. You can follow their blog here.