Tag Archives: CODAR

A Glider Joins Forces With the Krill Team

The gliders have been out on their own for more than a week. In that time they’ve traveled far out to sea, but today the team decided to turn one of them around and bring it almost all the way back home. Being close to shore is actually more dangerous for a glider than being in deep water, but they thought it would be worth the risk to meet up with the krill team’s echosounder and combine the two instruments’ strengths.

Click through the slideshow to learn about the glider’s travels—then check below for a quick look at what the two instruments found together:

The Traveler Returns Converging on a PlanHazard in the Boating ZoneA Glider in Your Rearview MirrorDoubling UpTransponder BluesWhip in the Wind

glider transect data with krill results
This graph helps show how two instruments combine to create a better picture of what’s going on under the water’s surface. To read it, imagine that the glider is flying from left to right on the graph. As it moves slowly along this 1.5-mile track, it dives from the top of the graph to the bottom and measures chlorophyll levels. That gives an estimate of the amount of phytoplankton in the water, and phytoplankton are the main food of krill.

Now imagine the krill team driving their zodiac along the same route. The boat moves along the top of the graph (the surface of the water), and the echosounder detects patches of krill below it. Interestingly, the glider found a fairly high concentration of chlorophyll high in the water on the left side of the graph. The krill team found a patch of krill in deeper water beneath it, but not anywhere else.

“That’s pretty neat to find,” Dr. Kohut said, “that the only place on the whole transect there was krill was underneath the patch of chlorophyll.” The krill may have been resting during the day before swimming up to eat phytoplankton later in the day, Dr. Oliver said, or they may have been feeding on organic material as it drifted downward from the phytoplankton patch.

What’s really interesting about this find is that it couldn’t have happened without putting the two instruments—glider and echosounder—together. If the glider had been on its own, it would have noticed the phytoplankton, but we couldn’t have known whether krill were around to feed on it. On the other hand, if we’d had only the findings from the echosounder we’d have known there were krill around but we wouldn’t know why.

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Antarctic Radar Station, Some Assembly Required

Our main research mission—and our daily blog—will kick off just after Christmas. But the science team has already put in a ton of effort (actually it was about 8 tons of effort, as you’ll see in the slideshow). Scientists and technicians from the University of Alaska, Fairbanks, spent several weeks in November setting up radar locations on two small, snowbound islands near Palmer Station. These solar- and wind-powered stations will scan the horizon and generate detailed maps of the ocean’s surface currents for us. That’s crucial information that will help the rest of the science team piece together why the penguins forage where they do, and where their food is.

So how do you build a radar station on an uninhabited island with no power? Find out in this photo gallery:

ArrivalMoving DaySnowed InDigging PartyThe Station Takes ShapeMeeting the LocalsEasy Does ItOne Radar Station, Ready for Duty

After two weeks of solid work, the team had the two radar stations (plus one at Palmer Station itself) up and running by November 15. They spent the next couple of days calibrating their system. By November 16, Dr. Josh Kohut was logging into the radar systems all the way from his office at Rutgers University in New Jersey, in between donuts. He analyzed the data and produced these colorful maps of surface currents in the vicinity of Palmer Station. (The small red dots mark the locations of the radar stations.)

The brighter colors indicate faster-moving water. The scientists (and many of the students who follow along on this blog) will use these maps to figure out where and when krill might accumulate, creating possible feeding grounds for penguins. And that’s what the rest of the group will be studying when they arrive in January.

Hank Statscewich, Dr. Peter Winsor, and the rest of the installation team boarded the Gould and returned to Punta Arenas, Chile, soon after; they’re now back home in Alaska. Meanwhile, Dr. Kim Bernard, Shenandoah Raycroft, and Megan Cimino have arrived at Palmer Station, and we’ll check in with them soon.

(Thanks to Hank Statscewich for his descriptions of the work, and to Peter Winsor for the photographs.)


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