We will swim in numbers

by srosengard

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Sideways image of Oceanus harbored in Resurrection Bay, Seward, Alaska.

The R/V Oceanus is my new home for nearly the rest of August. It is ~170 feet in length, roughly 2/3 that of a Woods Hole commuter ferry or (because I now live in Vancouver) half the length of a Vancouver Island ferry. And, as we steam out of the fjord that is Seward Alaska, where every direction is a Chugach mountain, it is easy to feel dwarfed by the world on Oceanus’s main deck.

Nonetheless, from now until August 27th, a remarkable quantity of science per square foot will happen on this ship. Most of thirteen scientists on board are interested in a chemical compound in seawater called dimethylsulfide (DMS is the acronym). So, for the first time, I travel among company that cares primarily about the movement of DMS in the ocean – not the carbon cycle (though the two cycles are related)! Like carbon, DMS transforms into other chemical forms in seawater. Sometimes, life in the ocean – mainly small things like algae and bacteria – drive these changes. Other times, abiotic factors, like UV radiation from the sun, can add an oxygen atom to the DMS molecule. These transformations are complex, and it makes sense that you’d need at least ten people per ship to study them; more details will come later as I get to know my all of my scientist roommates.

What I mostly know so far is this: the DMS molecule is responsible for the ocean’s smell. Which some of us love! As a gas, it easily escapes the sea into the atmosphere. Scientists have long posited that if DMS travels high enough in the atmosphere, it can trigger clouds to form, playing an important role in our planet’s climate. Thus, if something shifts the production of DMS in the ocean, it can ultimately affect the climate we experience on land, as well.

Coming from Philippe Tortell’s diverse team at University of British Columbia, I can still measure those constituents of seawater that tell us about the marine carbon cycle. Between here and Newport Oregon, I will continuously monitor how light at just 5 meters (~16 feet) below the ocean surface gets absorbed or scattered in seawater. These optical properties can tell us about the solid particles of organic carbon in the water, and more specifically, the different types of algae that produce these carbon particles. More later on that too.

And for a relatively small research vessel, the volume of numbers that we will get in just sixteen days is massive. My team alone, a group of five, specializes in the development and deployment of equipment that analyzes seawater incessantly by taking seawater that the ship pumps from 5 meters below surface to the main deck. One instrument I will use can provide me several seawater absorption numbers per second. Recall that this is quite different from graduate school, where I would spend weeks acquiring the equivalent of thirty data points on a graph. After two weeks, that is tens of thousands of numbers and 4-5 orders of magnitude more coverage of what is going on in the ocean’s surface.

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