A Weddell seal doing its thing
Photo: Andrew Purdam/Flickr

Michelle LaRue has a problem: She only has one set of eyes.

That’s a big issue when you’re an ecologist who uses satellite imagery to understand what’s going on with Weddell Seals, the southernmost mammal on the planet. The seals can help us unlock secrets about how coastal ecosystems and fisheries function in Antarctica, as well as how ice clinging to the continent will react to climate change.

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LaRue, an ecologist at the University of Minnesota, had been trying to think of a way around the one pair of eyes-problem for years. Then a chance conversation with someone from the DigitalGlobe Foundation—the nonprofit arm of a commercial satellite company—changed everything. It offered LaRue a chance to get her project on Tomnod, a crowdsourcing site that asks users to scour satellite images.

Since 2016, hundreds of thousands of eyes scattered around the world have scanned more than 116,000 square miles of Antarctica’s coastal ice, looking for seals that look like black grains of rice. There’s never been a crowdsourced project quite like it in Antarctica, and the dataset it’s creating has the power to transform our understanding of the region.

“Quite literally, there’s no way this could’ve been done any other way, especially in that amount of time,” LaRue told Earther.

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Tomnod was initially conceived by scientists at the University of California, San Diego in 2010 as a way to harness the power of the masses to analyze the growing terabytes of satellite data. Its first project asked volunteers for help scouring the Mongolian steppe for Ghengis Khan’s tomb. The search was unsuccessful at finding the tomb, though Tomnod—the Mongolian word for “big eye”—stuck as the project name.

Tomnod has since invited various researchers and humanitarian groups to plug into its huge network of volunteers and wealth of satellite imagery. Project have included looking for signs of food insecurity in South Sudan, and more recently, looking at satellite imagery of Puerto Rico from before and after Hurricane Maria to find trash, blocked roads and bridges, and identify hard-hit areas.

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“In some ways, the Antarctica project is perfect fit for Tomnod,” Melissa Dozier, one of the people who runs the project, told Earther. “The goal is really to understand more about Weddell seal habitat and population numbers [which is] an impractical thing to do from ground.”

After providing some basic instructions, Tomnod serves up a satellite image taken between 2010 and 2011. Volunteers are tasked with looking at it and then checking a box for seals if they spot seals, or no seals if they don’t.

In practice, this means looking at a lot of white ice with no seals. I’ve gone through a couple dozen images and spotted nothing, though I did check the seals box once by mistake (sorry!). Dozier said the platform serves up the same images to multiple users and has an algorithm to help weed out false positives.

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Tomnod in action. No seals here.
GIF: Satellite image ©2018 DigitalGlobe

Despite the very low probability of seeing seals from space, people keep coming back to contribute. LaRue said there’s one user who has viewed more than 20,000 images, and there are about 15-20 other super users who have contributed a ton to the project.

“The fact that people have been engaged in this knowing they’re very unlikely to see seals, I’m continually amazed,” she said.

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In some ways, it’s soothing to look at the white ice and various shapes it takes. But the empty expanses are also valuable scientific discoveries in their own right, providing key data about seals’ habits and preferred habitat.

“It’s important to know where they’re not,” LaRue said. “In doing habitat suitability modeling, knowing presence only is a big limitation. That (knowledge of where they’re not) makes our science more robust.”


When they’re not diving 2,000 feet under the Southern Ocean, Weddell seals spend their time lounging on Antarctica’s ice. Scientists have studied them for decades at McMurdo Station—the U.S. research facility located in West Antarctica—and learned a lot about their behavior and diet.

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They know, for example, that seals hunt toothfish. So do humans. Finding out where the seals spend their time when they’re not hunting could be a major boon for fisheries management in the region.

Scientists also know that the seals love to hang out on fast ice, which steadfastly clings to the continent or in some cases, the ocean floor. According to the Australian Antarctic Division, the ice “acts like a belt around the Antarctic coast, regulating the flow of ice shelves and glaciers into the sea.” Its health is intimately tied to how fast seas will rise, but despite this, LaRue said modeling it has proved challenging.

Seals! The red arrows point to seals on the ice.
Image: Satellite image ©2018 DigitalGlobe

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That makes the seals a key climate indicator. Understanding how populations move around Antarctica could help researchers get a better handle on fast ice health now, and improve models that predict what the future holds.

The first round of it seal surveying is nearly completed, and LaRue said the next step is to go back to the satellite images with seals and ask Tomnod volunteers to actually count them. (While there’s no telling yet how many seals have been flagged in the satellite images, there are an estimated 800,000 across Antarctica, according to the Seal Conservation Society.) From there, users will look at imagery taken in more recent years to see how populations are changing. That data then goes back to LaRue, who said she can tease out what might be causing changes based on research done at McMurdo Station and elsewhere.

With the impacts of climate change likely to pick up pace, this project and other innovative uses of technology are only becoming more important. It may seem strange, but there’s a real chance that understanding these seals could help coastal communities prepare for future floods.

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“The value of the crowd is many hands making light labor,” Dozier said. “If you had one scientist doing this all, it would take the them rest of their life. We’re able to move at the pace that matters.”

This post has been updated to reflect that DigitalGlobe is commercial but not private. Its parent company is publicly traded.