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Keith Holmes/Hakai Institute
Keith Holmes/Hakai Institute

Drone Captures Massive Swarm of Jellyfish Off British Columbia That Weighs More Than 70 Tons

Keith Holmes/Hakai Institute
Keith Holmes/Hakai Institute

Drones have served science in myriad ways, from planting trees to vacuuming marine debris to predicting tornadoes. Now, a team of researchers has used one to measure the size of a massive bloom of jellyfish off the coast of British Columbia, Canada. And it's a monster: According to a new paper in the journal Marine Ecology Progress Series, the huge swarm weighed more than 70 tons.

That's at least 150,000 individual jellies.

"The size of the bloom surprised me. What was exciting was going from not being able to see the bloom easily, if at all, to instantly being able to find them from the air," says co-author Brian Hunt, the Hakai Professor in Oceanography at the University of British Columbia in Vancouver, B.C. "It is remarkable how tightly they group together."

Jellyfish bloom in Pruth Bay, British Columbia
Keith Holmes, Hakai Institute

The bloom is comprised of five species in the Aurelia genus, also known as moon jellies. They're found worldwide (and in aquarium exhibits), often gathering in quiet harbors and bays to feed on plankton, fish larvae, crustaceans, and mollusks.

Hunt and colleague Jessica Schaub conducted their survey in Pruth Bay, a peaceful waterway edged with dense forests, near Calvert Island on the province's central coast, roughly 375 miles north of Seattle. The Hakai Institute, a scientific research institution that supported the survey, faces the bay. The area is within the First Nations territories of the Heiltsuk and Wuikinuxv Nations.

This is the first time a drone has been used to locate and study jellyfish blooms, Hunt tells Mental Floss. Previously, scientists viewed the groups at water level, which provided a limited perspective on their true size and density. The aerial view can help researchers estimate the biomass of jellyfish more accurately and reveal aggregations' behavior, such as their movements in currents or tides.

The team deployed the drone from a research vessel positioned within the mass of invertebrates. While the drone captured aerial images, the researchers also sampled the waters with nets. Then, they compared the drone data and sampling, and estimated that the bloom could weigh anywhere from 70 to as much as 128 tons.

Jellyfish bloom in Pruth Bay, British Columbia
Keith Holmes, Hakai Institute

There isn't much long-term data about the blooms, Hunt says, but those living in the area are familiar with the jellies' appearances in the waterways. "I wouldn’t call these events common, but they are definitely consistent in their timing. We see this happening every four or so years, particularly the local fisherman who catch them as bycatch in their nets," William Housty, chair of the Heiltsuk Integrated Resource Management Department's board of directors, tells Mental Floss.

In the future, drones might help scientists interpret the blooms based on where, when, and how often they occur—as well as how they affect the surrounding ecosystem. Housty says these jellyfish may be following the pattern of warmer waters along the coast.

"We did notice higher numbers during the 2015 marine heatwave and the 2016 El Niño [also a warm event]," Hunt says. "It is possible that changes in the seasonal timing of the jellyfish life cycle might be as or more important than increasing numbers. For example, if jellyfish are more advanced in their life cycle in the spring, they might have a bigger predation impact on herring larvae."

Soon, thanks to aerial imagery, we might know more about the jellies' secret lives.

This story was made possible in part through the Institute for Journalism and Natural Resources.

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Big Questions
What Causes Sinkholes?
Mark Ralston/AFP/Getty Images
Mark Ralston/AFP/Getty Images

This week, a sinkhole opened up on the White House lawn—likely the result of excess rainfall on the "legitimate swamp" surrounding the storied building, a geologist told The New York Times. While the event had some suggesting we call for Buffy's help, sinkholes are pretty common. In the past few days alone, cavernous maws in the earth have appeared in Maryland, North Carolina, Tennessee, and of course Florida, home to more sinkholes than any other state.

Sinkholes have gulped down suburban homes, cars, and entire fields in the past. How does the ground just open up like that?

Sinkholes are a simple matter of cause and effect. Urban sinkholes may be directly traced to underground water main breaks or collapsed sewer pipelines, into which city sidewalks crumple in the absence of any structural support. In more rural areas, such catastrophes might be attributed to abandoned mine shafts or salt caverns that can't take the weight anymore. These types of sinkholes are heavily influenced by human action, but most sinkholes are unpredictable, inevitable natural occurrences.

Florida is so prone to sinkholes because it has the misfortune of being built upon a foundation of limestone—solid rock, but the kind that is easily dissolved by acidic rain or groundwater. The karst process, in which the mildly acidic water wears away at fractures in the limestone, leaves empty space where there used to be stone, and even the residue is washed away. Any loose soil, grass, or—for example—luxury condominiums perched atop the hole in the ground aren't left with much support. Just as a house built on a weak foundation is more likely to collapse, the same is true of the ground itself. Gravity eventually takes its toll, aided by natural erosion, and so the hole begins to sink.

About 10 percent of the world's landscape is composed of karst regions. Despite being common, sinkholes' unforeseeable nature serves as proof that the ground beneath our feet may not be as solid as we think.

A version of this story originally ran in 2014.

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DNA Analysis of Loch Ness Could Reveal the Lake's Hidden Creatures
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iStock

Stakeouts, sonar studies, and a 24-hour video feed have all been set up in an effort to confirm the existence of the legendary Loch Ness Monster. Now, the Associated Press reports that an international team of scientists will use DNA analysis to learn what's really hiding in the depths of Scotland's most mysterious landmark.

The team, led by Neil Gemmell, who researches evolutionary genetics at the University of Otago in New Zealand, will collect 300 water samples from various locations and depths around the lake. The waters are filled with microscopic DNA fragments animals leave behind as they swim, mate, eat, poop, and die in the waters, and if Nessie is a resident, she's sure to leave bits of herself floating around as well.

After extracting the DNA from the organic material found in the water samples, the scientists plan to sequence it. The results will then be compared to the DNA profiles of known species. If there's evidence of an animal that's not normally found in the lake, or an entirely new species, the researchers will hopefully spot it.

Gemmell is a Nessie skeptic, and he says the point of the project isn't necessarily to discover new species. Rather, he wants to create a genetic profile of the lake while generating some buzz around the science behind it.

If the study goes according to plan, the database of Loch Ness's inhabitants should be complete by 2019. And though the results likely won't include a long-extinct plesiosaur, they may offer insights about other invasive species that now call the lake home.

[h/t AP]

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