Harnessing the MOCNESS

Back deck of the Nancy Foster

We’re nearing the continental shelf edge off southwestern Florida. It’s a beautiful morning, still balmy; a light breeze keeps the air tolerably fresh before the tropical sun reaches a scorching zenith later in the day. But there is little time to relax and enjoy the surroundings. The Nancy Foster is a working ship, with heavy gear, and a ship and scientific crew who work 24 hours a day, every day. Time on research ships is preciously expensive, so everyone maximizes their opportunity at data collection.

At breakfast, the ship stops entirely, and the scientific team deploys sampling tows. One of these is the huge MOCNESS gear. MOCNESS stands for “Multiple Opening/Closing Net and Environmental Sampling System.” Towed from behind the vessel, it consists of five to twenty nets that are computer controlled to open and close at desired depths to catch plankton at various levels. An instrument package at the top of the MOCNESS collects and sends data about the water column (such as temperature, salinity, depth, and chlorophyll) to computers on board.

The MOCNESS

By late morning, when this station is completed and we are once again underway, the water turns a deep violet-blue, transparent color, with shafts of light piercing the depths visible from high on the ship’s bridge. We finally cross into water more than a mile deep, thereby increasing our chance to see the more pelagic species of marine life, including birds. Small clumps of Sargassum appear, a few flyingfish glide ahead of the bow, startled by the ship’s sudden appearance in their quiet ocean.

A buzz of excitement bounces around the entire ship today. We learn that the Incident Command Center for the Deepwater Horizon response has approved the Nancy Foster’s research plan to enter the center of the oil spill during the next few days. This unique team of NOAA researchers, affiliated with Miami’s Atlantic Oceanographic and Meteorological Laboratory, has

Underwater view of the MOCNESS, photo credit Gulf Maine Research Institute

specialized instrumentation that tests for oxygen levels in deep water. The tests are more reliable than those widely reported by the media, because the procedure is immune to the oil “fooling” less sophisticated equipment with false readings caused by clogged sensors.

I find myself unexpectedly reserved about going into the spill zone. So far, I’ve not seen any conspicuous evidence of oil in the waters that we are crossing. There is so much scrutiny that not even a floating styrofoam cup or milk carton passes us by without careful inspection. But as of today, the 85th day of the disaster, between 92 million and 182 million gallons of oil have spewed into the Gulf of Mexico. Where can that much oil be? It’s somewhere between us and our port destination. So, to be on the safe side, all of the scientific staff on the Nancy Foster are being fitted with respirators. My beard will have to go; a respirator must fit closely.

 It isn’t the startling new look of being clean-shaven that bothers me. Rather, I’m reluctant to part with the picture of the Gulf that I have right now. Calm and clear seas, blue skies, and off our starboard bow a sunset to end a productive day.