Tag Archives: icebergs
True to its name, Project CONVERGE brought together people from all over the world to study the food web at Palmer Station. But now our month on the ice is over, and it’s time for us to go back home; in other words, it’s time for CONVERGE to diverge.
As we said our goodbyes to our friends at Palmer and to the incredible scenery surrounding it, we couldn’t help but notice some signs of the passing time. Icebergs were smaller; the thick cap of winter snow on the glacier had melted away to bare ice; and it was actually starting to get dark at night. Click through the slideshow to see more signs of the changing season:
Most of the Project CONVERGE team is now back home. Down in Punta Arenas, Chile, the Laurence M. Gould is already loading up a new set of scientists and preparing to head back across the Drake Passage to Palmer Station again. We’ve had an unforgettable time on our Antarctic expedition, and we hope you’ve been able to share with us an idea of what it’s like to live and work among the penguins, seals, whales, and icebergs.
Thank you for reading this blog and being a part of this project. The questions you sent in, the ones you asked during the video calls, and the ones that you’re investigating on your own, have made you an important part of Project CONVERGE, too. We’re looking forward to meeting as many of you as possible during our science symposium in April. Until then, stay warm and don’t let the penguins bite!
The scientists spent Sunday doing maintenance on a glider, checking giant-petrel and skua nests, looking for whales, and counting krill for as long as the choppy water and the sharp south winds allowed. Dr. Josh Kohut and Dr. Matt Oliver looked nervously at the changing iceberg landscape outside our front door. Winds and currents keep reshuffling the bergs, and the team really doesn’t want to hit one with their glider.
Photographer Chris Linder has a lot less anxiety when he looks at ice. He’s photographed ice of all sizes, at all times of day, and from pretty much every angle. We thought this quiet Sunday was a fine time to show you some of what he’s seen. Click through the slideshow to explore:
In yesterday’s post, the glider team took a calculated risk and brought glider RU05 into the shallow waters near shore. We made a big deal about how dangerous this was—how the waters near shore are full of obstacles like rocks, islands, icebergs, and squirrelly currents. But we also said that everything went fine and the glider team was already planning more. If it sounded like maybe shallow water wasn’t so dangerous to gliders after all, then today’s post is for you.
Late yesterday evening, glider RU05 dove to the bottom of the sea as usual, but it never came up. When Dr. Josh Kohut woke up this morning, he had a text from the glider pilots in New Jersey: RU05 has not checked in for more than 8 hours. Something was keeping it underwater.
We spent the rest of the day figuring out what had gone wrong. Click through the slideshow to see what happened to the glider and how the team fixed it:
This evening, glider pilot Dave Aragon looked at the glider’s data files and made this schematic showing what he thinks happened. The glider was doing its normal job, repeatedly diving to the bottom and rising to the surface, and measuring the water along the way. The zigzag black line shows the glider’s actual path. Aragon thinks the glider did fine but may have flown into a patch of kelp (a type of very large seaweed). The thick kelp stems got tangled in the glider and didn’t let it go until 12 hours later, when it dropped its emergency weight.
This is one of the hard parts of working with gliders. They may be sophisticated machines, but they can’t see in front of them, they have limited battery life and limited maneuverability, and once they go below the surface they can’t contact the glider pilots for help. If it gets caught underwater, there’s a very real chance the scientists will never see it again. Today, we were lucky.
“Off New Jersey the shallows don’t really present a danger to the gliders,” Dr. Kohut said. “Here with all the kelp and the rock it’s much more hazardous. But I’m still happy we sent the glider in close to shore because we got all that very nice data to go along with Kim [Bernard]’s transect.” From now on they will be a little more careful around shallow water, though. “Before this, we knew we needed to avoid islands,” he said. “Now we’ve expanded our definition of an island to include water up to 20 meters deep.”
At about 1:00 p.m. today, Dr. Josh Kohut was in an inflatable boat over an underwater canyon called the Palmer Deep. The wind was light, there was a little rain, and groups of gentoo penguins were swimming by the boat to see what we were up to. We were there to deploy four gliders—or, as Dr. Kohut put it with mild amazement, “Here we are in Antarctica, sitting in a zodiac and getting ready to throw some robots in the water.”
The team’s gliders are indeed torpedo-shaped robots that will “fly” through the water measuring basic aspects such as salinity, currents, and photosynthetic activity. They’ll stay out for weeks at a time, and they’ll check in every few hours to report what they’ve found and listen for further instructions. The CONVERGE team is using them to gather data about what’s going on under the surface, much as they’re using radar to study the surface water and find convergence zones.
“We think convergence zones are concentrating the food web [phytoplankton and krill],” said Dr. Matt Oliver of the University of Delaware. “So these gliders are going to go fly through those zones and find out if that’s true.” In scientific terms, the effect of convergence zones is one of the team’s hypotheses, and the gliders provide them with a way to do what scientists do: test their hypotheses.
Gliders are delicate, heavy, complicated machines—see what it takes to safely launch a glider in the slideshow below:
All the time we were driving the zodiacs back to Palmer, the gliders were heading out along their programmed routes. By late evening, RU05 had split away from the others to follow its own route. The Alaska glider (AK03) and the University of Delaware’s Blue Hen were neck and neck, but Filipa Carvalho’s RU24 was out in front, owing to a slight difference in the way it was configured during testing.
The gliders will keep sending back data every few hours, and the CONVERGE team will get together each day to look at the results and decide on their next course of action. This almost instantaneous collection of data over such a wide area is something that has only become possible in the last 10 or 15 years. Check back over the next days and weeks to see how the team puts this potential to use.