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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  1. Ms. Heckel January 14, 2015 at 11:24 am #

    Hi Hugh and Chris! My students in Verona, NJ love following your posts! We get excited every time a new one goes up! We were just reading today’s post in period 1 and were wondering if the krill and whale teams found that their data matched up and if equipment was properly calibrated. We were also wondering, how many hours the krill team spends out on the zodiac every day. The students were also wondering if it’s possible to attach an echosounder to a glider. They think it looks like you guys are having a blast! They would like to know on a scale of 1-10 (10 being the most fun), how much fun are you having? Lastly, they’re dying to know who’s the best at ping pong.

    • Hugh Powell January 17, 2015 at 5:25 pm #

      Hi to Ms. Heckel and your students from all of us here at Palmer Station! I asked Dr. Kim Bernard your question about calibrating the krill and whale team’s echosounder measurements. She said that those calibrations will be done at the end of the season. It’s most important for comparing the two team’s measurements together—for instance if the whale team wants to compare the krill team’s daily measurements with their daily observations of whales. For your other questions: the krill team spends about 7 hours a day out on the water. Your idea to put an echosounder on a glider is a good one—the main problem is that echosounders take a lot of battery power, and gliders are pretty limited in the number of batteries they can carry. Dr. Bernard says on a scale of 1-10 she is having fun at the ’10’ level. I’m not sure who’s the best at ping-pong, but Dr. Bernard says it’s not her. Thanks for reading along and for asking these great questions. – Hugh

  2. Omer January 14, 2015 at 3:47 pm #

    How large is your largest glider that you send out.

    • Hugh Powell January 15, 2015 at 9:29 am #

      Hi Omer – All the gliders on this project are about the same size. They’re about 5 feet long and weigh about 100 pounds. Thanks for asking – Hugh

  3. Murium W. January 15, 2015 at 8:37 pm #

    I’m one of Mrs. Hester-Fearon’s eighth grade students and I was just wondering a few things. It was mentioned that the krill team’s echosounder and the glider worked together to find that data. Is it possible that there could be a new piece of equipment that combines the purposes of both the echosounder and the glider? So, instead of having to use both separate pieces of equipment (even if it was an accident), there could just be one tool that can still collect all that data?
    Also, how many gliders are being used in Project Converge? Do you have back-ups in case you (and the team) wouldn’t be able to retrieve/rescue a broken or missing glider?
    You guys are doing an amazing job and I hope you’ll be safe out there.

    • Hugh Powell January 16, 2015 at 11:47 am #

      Hi Murium, It’s a great idea to combine the equipment so that one instrument could collect all the data we need. The biggest problem with putting an echosounder on a glider is battery life. The glider has to be very economical on power because it stays out for so long, and an echosounder requires a lot of energy to run. We are using 3 gliders as part of Project CONVERGE, and there are another two gliders down here that are part of related research projects. We don’t have backups so if we were to lose or break one, Dr. Kohut and his team would have to get creative about how to use their remaining gliders to gather as much data as they can. Thanks for these good questions – Hugh

  4. Gregory D January 22, 2015 at 10:57 pm #

    Hello I am one of Mrs. Hester-Fearons’s eight grade students. I have been wondering why the gliders are so large? Is there a way to make the gliders smaller? Also, as you stated in one of the previous answers is there a way to make the gliders even more power efficient than they are already? I think that the smaller the gliders are that the farther they can go and that maybe the gliders will be able to fit into smaller spaces. Thank you for all your hard work over there in Antarctica and i wish your team a safe time there.

    • Hugh Powell January 26, 2015 at 9:29 pm #

      Hi Gregory – Great questions. I asked Dr. Matt Oliver and Dr. Josh Kohut, and they said that gliders are a balance of size and performance. If you make them smaller, then you can’t fit as many sensors in them, and you can’t fit as many batteries in them so they can’t stay out as long. If you make them bigger, they’re harder to launch from a zodiac and they take more energy to fly. The size they’re using right now seems to work well for the conditions they encounter—although there are other designs being tested. Thanks for asking – Hugh

  5. Maximilian January 23, 2015 at 2:23 pm #

    HI I am one of Mrs Hester Fearon’s student. I’m very curious on how you get the gliders deeper into the water. I have some great ideas on how to get a better design. I also want to know what you are doing to get the gliders down there with the weight it has. Once again I hope you and your team stay safe and have amazing trips. If anything contact Mrs Hester Fearon and she will give me the latest info.

    • Hugh Powell January 24, 2015 at 10:45 am #

      Hi Maximilian – That’s great that you are coming up with ideas about making better gliders—maybe you can be an oceanographer, glider pilot, or glider engineer someday. The gliders go down into the water by adjusting their buoyancy. They fill part of their body with water; this makes them heavier relative to the water around them, and they sink. When they need to come back up, a pump pushes water back out of their body and replaces it with air. This causes the glider to become lighter than the water around it, and the glider rises back to the surface. It’s tricky to get gliders adjusted perfectly so that they rise and sink the way we need them to – but the bigger of the two problems is making sure they come back up! Thanks for your question, – Hugh

  6. Jennifer Chen January 26, 2015 at 12:42 pm #

    Do the gliders sample the living organasms? If so how?

    • Hugh Powell January 26, 2015 at 8:21 pm #

      Hi Jennifer – The gliders have some sensors that can measure some aspects of small living organisms. They use two sensors (fluorescence and backscatter) to estimate how much microscopic phytoplankton is there. They also use a different kind of backscatter sensor to get an estimate of larger organisms like krill (which are still fairly small, relatively speaking). The gliders don’t sample larger organisms like penguins or whales. Thanks for asking – Hugh

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