Kuba Tatarkiewicz, Shohei Watanabe, Rick Reynolds, and Dariusz Stramski on Ice Liberty outside of USCGC HEALY. (Photo: Haley Smith Kingsland)
Kevin Arrigo is a Professor in the Department of Environmental Earth System Science at Stanford University. He is the Chief Scientist for NASA’s ICESCAPE (Impact of Climate change on the Eco-Systems and Chemistry of the Arctic Pacific Environment) mission this summer onboard US Coast Guard Cutter HEALY.
Light. During our waking hours, it surrounds us constantly, yet we give it very little thought. However, ICESCAPE takes light very seriously. That’s because light not only allows us to perceive this spectacular Arctic environment, it also tells us a great deal about that environment.
ICESCAPE has three research groups dedicated to studying light in the ocean – a science called ocean optics. One of them, led by Rick Reynolds and Dariusz Stramski (Scripps Institution of Oceanography), is focusing on how light interacts with the myriad shapes and sizes of particles that float beneath the ocean surface. They are especially interested in the tiniest particles that are rarely studied but are the most abundant.
Rick and Dariusz use a couple of techniques to study how light interacts with particles. In one, they take water samples and put them into some state-of-the-art particle counters. However, these instruments don’t just count the particles — they determine their size, and if possible, what they are made of. In the other technique, they drop a suite of instruments into the water and measure how much light is absorbed and scattered at different depths. By comparing these two sets of measurements, they can better understand how particles affect the water’s color.
Why do this? Because once we understand what gives the ocean its color, we can measure that color and learn a great deal about what is in the ocean. A blue ocean? Probably lots of little particles — but not much else. Kind of a desert. A green ocean? A veritable oasis of phytoplankton. A brown ocean? Either lots of colored dissolved matter (like the stuff that makes your tea brown) or floating particles of dirt and mud. With enough information, we may even be able to tell different phytoplankton groups apart just by measuring ocean color from space using satellites.
Fortunately, ICESCAPE’s slice of the Arctic Ocean contains many different colors of water for the duo to sample. As Rick puts it, “One of the interesting things for me so far on this cruise has been how things change so dramatically in such a short distance.”
This poses many more challenges than you might encounter in areas of the ocean that are much more uniform. Yet our intrepid oceanographers remain undaunted about sampling Arctic waters. “It’s an exciting place to work because it’s challenging,” Rick notes.
I couldn’t agree more!
Check out the rest of the Armed with Science ICESCAPE series! You can also visit NASA’s Arctic Voyage 2010 blog and get updates from Ensign Emily Kehrt, HEALY’s Public Affairs Officer.
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