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Images: Uncovering the Ocean's Biological Pump

To measure particles at sea, marine geochemist Dan Ohnemus and colleagues literally vacuum them out of the water. They wrestle 150-pound, bellybutton-high, battery-operated pumps onto a wire and lower them down to various depths in the ocean. (© Chris Linder / www.chrislinder.com. For more information about the Ross Sea project visit: http://coseenow.net/ross-sea)

Dan Ohnemus unloads pumps that have sucked in seawater samples containing particles floating in the ocean. He analyzes those particles to reveal the movement of chemicals in the ocean. (© Chris Linder / www.chrislinder.com. For more information about the Ross Sea project visit: http://coseenow.net/ross-sea)

Filtering seawater, marine geochemists obtain samples of particles floating in the ocean. The particles transport chemicals through the ocean, even to great depths. (© Chris Linder / www.chrislinder.com. For more information about the Ross Sea project visit: http://coseenow.net/ross-sea)

To prevent contamination of their samples, WHOI scientists Phoebe Lam and Dan Ohnemus work inside a plastic bubble lab set up inside their ship. Filters pump clean air into the plastic bubble and keep the space at positive pressure. So if there is a leak in the bubble, clean air will leak out, rather than contaminated air leaking in. (© Chris Linder / www.chrislinder.com. For more information about the Ross Sea project visit: http://coseenow.net/ross-sea)

Dan Ohnemus, who earned his Ph.D. at WHOI in 2014, is now a postdoctoral scientist at Bigelow Laboratory for Ocean Sciences in Boothbay, Maine (which isn't quite as snowy and cold as Antarctica, where this photo was taken). (Courtesy of Phoebe Lam, Woods Hole Oceanographic Institution)