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If you’re looking to grow  your STEM skills this year, head to Brilliant.org/SciShow and check  out their Scientific Thinking course.   [♪ INTRO] You might have heard of Alaska. It's known for the Klondike Gold Rush, polar bears, and an unreasonably elaborate  dessert: the baked Alaska.

It’s also geographically distinct  from the rest of the United States, being very far north, with its northern  slope peeking into the Arctic circle. And maybe science isn’t the first  thing that pops into your head when you think about this mostly-frozen region. But Alaska has a lot to offer when  it comes to learning about the world, from cold corals to our own behavior.

So let’s take a look at research  we’ve done by looking at Alaska. Like, for one, how to grow  some truly giant vegetables. Some of the US’s most impressive veggies  come not from sunny California or Florida, nor the breadbasket that is the Great Plains.

Rather, they’re grown in the Matanuska-Susitna  Valley area outside of Anchorage. And we are talking some real whoppers. Celery bunches the size of a child,  pumpkins that weigh as much as a cow.

The reason seems to be Alaska’s growing season, the time of the year in which temperature  and rainfall allow plants to grow. As you might expect, Alaska has a short one. But in that short time, plant  growth can be explosive.

During the short, warm summer months, the plants up there literally  make hay while the sun is shining. And it shines a lot. Like, almost the entire day, a lot.

The reason for this has to do  with the tilt of the Earth. Because the Earth’s rotational axis is a bit  tilted, the northern and southern hemispheres take turns getting the lion’s share of  sunlight as we travel around the Sun. Near the equator, this doesn’t matter  so much because the sun’s hitting you pretty much straight on throughout the year.

But the closer you get to the poles,  the more the axial tilt matters. The result is very dark  winters with very short days. But the flipside of that is during  the summer, days can get pretty long.

On the summer solstice, Anchorage can  get more than 19 hours of sunlight in a single 24-hour day. And it turns out plants love that. These super-sunny days give the plants more  time to turn the sun’s energy into sugars and starches through photosynthesis.

This helps fuel their growth,  letting them pack on the pounds. The extra sugars may also  contribute to Alaska’s reputation for having noticeably sweeter produce. But this leads us to point number two.

As we mentioned, the bright summer  days are kind of balanced out by long, very dark winter months,  with the sun only barely shining. On the winter solstice, the Alaskan city of  Anchorage only gets about 5 daylight hours. And, if you’re north of the Arctic  circle, the sun doesn’t come up at all.

But this also presents us with a natural  opportunity to study what happens to the people and animals that live through those dark months. One particular area of interest is  seasonal affective disorder, or SAD. Seasonal affective disorder  is a type of depression that seems to be tied to  the changing of the seasons.

If you have the most common type of it, you might notice that you start to feel moody and  tired in the fall and throughout the winter. As for why it happens, researchers think  it’s tied to the changing light levels affecting circadian rhythms,  hormones, and neurotransmitters. People who live in areas with more extreme shifts  in the amount of light throughout the seasons, like close to the poles, are  at a higher risk of SAD.

This variation gives us an opportunity  to understand more about how SAD works, in order to hopefully develop more effective  treatment for the people affected by it. For instance, looking at the prevalence  of residents in Alaska with SAD has given us evidence that SAD happens  more often in women than in men, and happens less often in  people over the age of 40. We can even zoom in further.

A 2021 study  looked at SAD in Alaskan gym-goers and found, perhaps counter-intuitively, that the more social  athletes were more likely to experience SAD. Those who hit the gym and just kind of focused  on doing their own thing were less likely. The authors suggest that it might be  because the more independent workout-goers are following more rigorous exercise regimens.

It’s just one study, but considering that physical  exercise is often thought of as being helpful for depression generally, this  could help shape recommendations for what kinds of exercise might  be beneficial for people with SAD. Now, Alaska’s proximity to the North Pole also  makes it fairly chilly, as you might expect. The poles don’t get as much direct, warm  sunlight like areas around the equator do, so it doesn’t get as warm.

In fact, much of the ground in  Alaska remains frozen long-term, what scientists call permafrost. In 2021, 85% of Alaska’s land  area had permafrost under it. However, thanks to the climate  crisis warming up the Arctic, much of that permafrost is now melting.

And by looking at what’s happening in Alaska, we can learn more about what will happen in  other Arctic areas, like Russia and Canada. Like, in Alaska, many homes and buildings  are built on permafrost and their foundations are now turning slushy and unstable. We can expect to see similar effects elsewhere.

Also, it turns out that melting  permafrost is releasing carbon dioxide. That’s because as the ground thaws, the frozen  organic matter like plant leaves and roots thaws as well, and becomes food for  soil bacteria and other microbes. As this organic matter decays, the  bacteria and other microbes release gases like methane and carbon dioxide.

And given that both are greenhouse gases,   this could be the start of  a positive feedback loop as it fuels even more atmospheric warming. Warmer conditions melt more permafrost which cases more greenhouse gases to be released, and so on. And one other really interesting thing that  might come out of those root-munching bacteria in the permafrost is antibiotic resistance.

Now, having antibiotic resistance  genes in soil bacteria isn’t unusual, because it’s actually pretty common for soil  bacteria to need to resist antibiotic compounds. That’s because soil bacteria actually  use their own home-made antibiotics to try to kill or stymie each other. Just because you live in the same  place doesn’t mean you’re friends.

There’s only so many nutrients  to go around, after all. But scientists have looked at the levels of  antibiotic resistance in permafrost bacteria and found that, at least  in the area they examined,   as the permafrost melts and is disturbed, the levels of antibiotic resistance seem to go up. This seems to be because the community of  different species becomes unbalanced by what’s essentially a huge ecosystem shift as the soil  goes from frozen and icy to thawed and muddy.

This frees up more water, nutrients, and even  other microbes that’d been previously frozen. In this case, the bacteria with the antibiotic  resistance genes may have some greater competitive advantage in this new  environment compared to their peers, since they might be able to, say, reproduce  faster since they can shrug off attacks. And this could be a problem for us, as these  antibiotic resistance genes can spread out of the soil and end up out in the wider world, which  could make infections in humans more dangerous.

So, by looking at what’s  happening in Alaskan soils, we can better track how melting  permafrost is going to affect the world. Next up is kind of a weird, famous, accidental  experiment that Alaska played home to. St.

Matthew Island is an about 350 square  kilometer island off the Western coast of Alaska, kind of in the middle between Russia and Alaska. It’s never really been  inhabited by humans long-term, but it was home to a navigational  facility by the US military for a time. In 1944, the United States Coast Guard  introduced reindeer to the island as an emergency food supply  for troops stationed there.

Reindeer had never lived there before. There were just 29 of them at first, but  with plenty of space and lichen to eat, the reindeer population exploded. There were also no significant natural predators;  just small mammals and the odd polar bear.

By 1963, there were as many as  6,000 reindeer on the island. But death was just around the corner, and  the next year, their population crashed to less than 50 animals. By the 1980’s, all the  remaining reindeer were gone.

What happened? Well, the reindeer overshot what ecologists  call the carrying capacity of the island. They ate their food faster than it could  regrow, leading to the entire population running out of food and starving  during an especially harsh winter.

This wasn’t a planned experiment, but it has  often been pointed to as an object lesson in carrying capacity, overpopulation,  and what can happen to herbivores if there aren’t predators around  to keep their numbers in check. Finally, the last lesson Alaska  has in store for us today comes not from an island, but from underwater. For years, fishing boats that  trawled nets along the ocean floor had occasionally turned up not just  crabs and lobsters, but pieces of coral.

And in 2002, scientists discovered that the waters  off Alaska’s Aleutian islands were, in fact, home to not just isolated individuals, but rich  gardens full of what’s known as cold water corals. While tropical corals thrive in  warm waters, basking in the sunlight and using symbiotic microorganisms to  produce their own food from the light, cold water corals often grow in frigid  waters, far away from the light. Some are shallow enough to scuba-dive  to, but many grow far beyond that.

The deepest a recreational scuba diver  will usually go is about 40 meters, but these corals can grow hundreds of  meters below the surface if not deeper. They still grow from polyps, the small coral  animals whose colonies create coral reefs. But these varieties don’t need the sunlight.

Instead, they eat what they can  catch floating in on the current. Despite not needing the light,  they’re still a sight to behold, with oranges, reds, and purples,  shaped in fans and feather-like forms. Deepwater corals have been found in  a bunch of places around the world, such as near the United Kingdom,  Norway, and New Zealand.

But Alaska in particular may have the highest  abundance and diversity of cold water corals anywhere in the world, with 25  endemic species and subspecies. The source of the corals’ success is  strong underwater currents that wind around underwater mountains and passes  and bring nutrient-rich waters. That allows the corals to grow in large “groves”, which provide important habitat  for fish and other sea critters.

Figuring out why there’s such high diversity  and abundance of cold water corals here could help us understand how  corals grow, disperse, and evolve. It could also help answer questions about  what environmental factors are most important for coral growth, how important the corals  are for fish and other ocean critter species, and how at risk they are  from human fishing fleets. So that’s Alaska in a nutshell!

Its position so close to the pole has  influenced life up there in amazing ways, from ultra-sunny summers to dark  winters and frozen landscapes. It’s a land of natural  experiments and amazing surprises. If you’d like to learn more about  how we can derive scientific insight from just about anywhere and anything, you might  enjoy Brilliant’s course Scientific Thinking.

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If that sounds like fun to you, you  can head over to brilliant.org/scishow to get 20% off an annual premium subscription. [♪ OUTRO]