In the 1970s and 80s, amphibian researchers started noticing the frogs and salamanders in their studies were mysteriously dying.

They suspected that the culprit was some sort of sickness but the deaths couldn't be explained by any disease they knew about at the time. In fact, the researchers remained stumped for decades but by the late 1990s they figured out where to put the blame, on a disease called chytridiomycosis.

Scientists now know that this disease is one of the worst destroyers of biodiversity ever and in their fight against it, they're taking to the skies, literally. Two types of fungus cause chytridiomycosis, they're both in the batrachochytrium genus and different amphibian species have a huge range of responses to them. A few have defenses on their skin that can resist the fungal infection and others seem to be able to withstand an infection without showing symptoms.

But then, there are the unlucky species. For these, exposure to as few as a hundred fungal spores is pretty much always fatal. The fungi work by targeting the animal skin and making it thicker.

And while that might not sound like that big of a deal, this affects the animal's ability to do all sorts of things essential to life: breathing, staying hydrated, regulating body temperature, obtaining nutrients, and releasing toxins. These fungi can also quickly spread between amphibians. So, maybe it's no surprise that we've talked about this disease before but since then our understanding of its impact has only become clearer.

For instance, a 2019 study found that chytridiomycosis could have caused the decline of 501 amphibian species including 90 we believe have gone extinct. When it comes to biodiversity loss, it could be the most destructive pathogen we know of. Now, there is some disagreement among scientists regarding how much of this is entirely the fault of chytridiomycosis.

Studying its impact is tough since most of the deaths happened in the 1980s before scientists discovered the fungus. So, to help them understand what's going on, some scientists have reached for a couple untraditional tools in the study of amphibians, satelites, and airplanes. For example, in the early 2000s, researchers wanted to figure out if factors like UV light could also be a part of this problem, maybe by helping the fungi spread or contributing to these deaths.

In mammals, we know that UV exposure can negatively impact the immune system. So, the researchers hypothesized that UV radiation on a frog's skin could limit its ability to detect and respond to a fungal infection. In a 2001 study, researchers used a NASA satellite to measure these variables in areas where they'd seen a lot of amphibians dying.

But, while they did find correlations between UV radiation and frog deaths at some spots, they didn't think the environmental factors could completely explain the extreme number of deaths. This doesn't mean that chytridiomycosis is definitely the only thing killing these amphibians but it did give researchers a clearer picture of what other variables might be involved. And, one way or another, scientists weren't done watching frogs from above.

From 1999 to 2000, another NASA project mapped frog habitat in Yellowstone National Park from airplanes because, to monitor frog populations, you kind of need to know where frogs are. Here, researchers used a hyperspectral sensor which can see the world in more kinds of light than our eyes. That meant that it could collect more data and could find the unique signatures of different types of ground cover that don't appear in visible light.

In this case, the team was looking for the signatures of algal ponds and wetlands to create a map of where frogs live in Yellowstone. And the results showed much more frog habitat in remote regions of the park than researchers thought existed. After this, the scientists went on to use the same methods in Idaho between 2002 and 2006 and were able to identify 72% of known frog egg locations from airplanes!

In studies like this, we might not be able to see the fungus itself from the air but figuring out where amphibians live is a major first step in tracking the disease and its impact. Overall, using airplanes and satellites has huge advantages. Scientists can quickly map large areas including those that humans don't frequent.

These methods also disrupt frog populations less which is critical since even going to study a group of frogs could spread the fungus to them. In fact, human trade and movement seem to be one of the biggest factors responsible for this disease spreading. Climate change and habitat loss also put more stress on amphibian populations.

For instance, warmer temperatures can encourage growth of the fungus. Despite all this though, there are signs of hope and not just when it comes to monitoring amphibians from the skies. As of 2019, 60 species were showing signs of recovery.

And on the Spanish island of Mallorca, researchers were even able to use fungicide to remove these dangerous fungi entirely in 2012. It was the first time eradication like that had ever been accomplished in the wild. Of course, there can be side effects and risks to using fungicide but it's a possible strategy if used carefully.

And whichever approach is used to treat the disease, the first step could be a survey from the air to locate the frogs in the first place. Really, all this is a reminder that while we have a long way to go, we as humans have the power to counteract some of the devastating ecological changes we create. With the fungus growing more in warmer temperatures, it's as if they are using some kind of solar thermal power and that's one of the concepts you can learn about with Brilliant.

Brilliant is a website that has guided exercises in math and science, including their solar energy course that examines the main methods used today to harvest energy from sunlight. By completing the course, you'll learn all about concentrated solar power and photovoltaic cells starting from their fundamental physics principles. And when you learn using Brilliant, you know you're getting high quality quizzes and exercises from people who know their stuff.

The solar energy course was written in collaboration with Dr. Lee Weinstein who got his PhD in mechanical engineering at MIT where he investigated how to generate solar thermal energy. But, you don't have to have a PhD from MIT to understand solar energy.

Brilliant's courses are accessible for people of all levels. To get started for free, click the link in the description down below or visit Brilliant.org/SciShow. You'll get 20% off the annual premium subscription.

Thanks to Brilliant for supporting this video and thank you for watching.