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When you imagine an ecosystem, you might picture an old-growth forest, or maybe a coral reef. But an ecosystem can be any place where living things interact with each other and their environment.

It can be very small, like a single tide pool, or very large, like an entire grassland. It can also be very odd. Around the world, living things have managed to build truly extraordinary ecosystems in some of the last places you would think to look.

Here are five unusual ecosystems that just go to show how innovative and adaptable life really is! Along the West Coast of the U. S., trees called coast redwoods grow taller than any other tree in the world; sometimes reaching up to 37 stories high.

People have admired these trees for a long time, but we've only recently started to pay attention to what's actually happening way up at the tops of them. In fact, it took til the late 1990s before people began exploring these redwood canopies because, well, scooting up a tree that's nearly as tall as a skyscraper isn't your typical field work. But when people finally got up there, they found way more than they expected.

In fact, redwood trees were so large, and extended so far from the ground, that their canopies had become ecosystems of their own. Scientists essentially found a forest growing on top of a forest, completely hidden from sight on the ground. Up in the canopy, single trees split into multiple trunks.

In one study, researchers counted 137 trunks growing out of a single tree. These aren't, like, little scrawny things, either. The trunks of these trees can be a meter wide, so you probably couldn't tell them apart from trees on the forest floor, except that they're 50 meters or more up in the air.

These weren't just redwoods, either. Trees of all different species, like Sitka spruce and Douglas fir, grew off of the redwoods' branches. Researchers even found a California bay laurel tree with its roots some 98 meters above ground!

And these trees can grow here because there is actually soil to grow in! Canopy branches grow really wide, sometimes two meters across, and they can get covered in ferns. Over time, these so-called fern mats trap dead branches, and broken trunks, and other debris, building up a layer of soil and organic material, a lot like what's on the forest floor.

And, like the forest floor, that soil is full of critters, like snails, and earthworms, and even moisture-loving salamanders. What are you doing all the way up there, little buddies?! So, these treetops are a happenin' place.

And now that scientists actually know what's going on up there, they can work on protecting these systems and all of the diversity that they support. For instance, they now know that it's not enough to protect young redwood forests, since they don't have these complex canopies that these old-growth forests have. But dwindling numbers of redwoods have isolated some of these canopy ecosystems, so scientists have begun looking at ways to speed up canopy growth in younger trees to help keep this incredible ecosystem alive.

There are lots of incredible ocean ecosystems, but the ocean floor is home to one especially unique one: whale carcasses. You might think of whales washing up to the shore when they die, but most of the time, dead whales actually sink, dropping all the way to the bottom of the ocean floor. These are called whale falls, and these dead bodies become incredible hotspots for underwater life.

We've actually found very few of these in nature because the ocean is so massive and so deep that it's pretty hard to look for things on the bottom. Like, in 2013, scientists discovered a whale fall more than 4000 meters deep in the Atlantic ocean. And that was only the seventh natural whale fall they'd ever studied in detail.

So other times, scientists have intentionally dropped carcasses into the ocean in order to better understand the ecosystems that develop around them. And what's amazing about whale falls is that they create an ecosystem in a place where, otherwise, not much can survive. There aren't many nutrients at the bottom of the ocean floor, but when a whale dies, literal tons of food arrive all at once.

And that attracts a huge diversity of creatures! Scientists have spotted animals like deep-sea octopuses, crabs, snails, limpets, and even bone-eating worms. They've even seen animals that they have never recorded anywhere else.

On one whale carcass, the majority of the 41 species researchers identified were totally new to scientists. These are exciting places to study marine life because we actually don't know a lot about what goes on undersea. I mean, only about ten percent of the ocean has even been mapped so far.

So whale falls are kind of like a microcosm of life in the deep sea, and they give scientists a rare chance to discover and learn about the species that thrive there. Apart from whale carcasses, there's also another place in the deep sea that hosts a totally different kind of ecosystem; one of the most chemically and physically extreme ecosystems on Earth. These are fissures in the ocean crust called hydrothermal vents, where blistering-hot water full of minerals bubbles out of Earth's crust.

And as unfriendly a place as it seems, lots of life has evolved to survive here. Since there's no sunlight that deep in the ocean, photosynthesis is a no-go. Luckily, these vents release a slurry of chemical compounds including sulfide, hydrogen, and methane, which these organisms can use in a process called chemosynthesis.

Basically, instead of using energy from the sun to convert carbon from the environment into organic compounds, organisms at these vents create organic compounds using energy from chemical reactions. Which is pretty incredible! But it's not just extreme microbial life living it up at these vents; their energy gets transferred up the food chain.

Even though temperatures can reach more than 350 degrees Celsius, yes, that's more than 3 times the boiling point of water, because the pressure is so great that is doesn't boil, the structures that form at these vents host creatures like giant tubeworms, mussels, clams, crabs, and shrimp. And now scientists are realizing that ecosystems at hydrothermal vents may actually have a really wide influence on the rest of the planet. These organisms consume the vast majority of the methane from these vents, preventing this powerful greenhouse gas from being released into the atmosphere, which would have an enormous effect on the Earth's climate.

These vents also release iron, which helps fuel the growth of phytoplankton, small organisms that play a big role in capturing carbon in the ocean. Aside from that, these hydrothermal vents might also help us understand some of our planet's earliest life, since they've existed ever since liquid water first accumulated on Earth. In fact, scientists have found traces of organisms from almost 4.3 billion years ago that lived at hydrothermal vents in the ancient seafloor.

So by studying the inhabitants of modern vents, we might gain insight into the Earth's earliest microbial communities. Now, you might not think of a giant hunk of ice floating through frigid waters as a great place to live, but for many creatures, an iceberg is a floating oasis. As icebergs float through water, even really icy water, they are always melting, at least a little bit, creating a pool of freshwater that surrounds the iceberg.

And as they melt, they release the dust and minerals that were frozen up in the iceberg, which are a good source of iron. The iron in that meltwater helps fuel photosynthesis, which stimulates the growth of phytoplankton around the icebergs, including some species of phytoplankton that normally live in freshwater. And even though icebergs are relatively small, they can have a pretty wide-reaching effect on the region around them.

That's because it can take over a year for a big iceberg to completely melt, so it can cover a lot of ground in that time and spread its minerals far and wide. In a study of giant icebergs between 2003 and 2013, researchers found a significant boost in chlorophyll production in the 500 kilometers surrounding the iceberg, and sometimes as much as a thousand kilometers away. These phytoplankton communities attract all sorts of other organisms to the area around the iceberg, including fish, krill, jellyfish, and seabirds.

Not only do they form the basis of this floating ecosystem, but phytoplankton also absorb carbon in the ocean. So understanding how icebergs are connected with these organisms can help us understand and predict the ways that climate change will affect our oceans, as more icebergs break off and enter the open sea. Although there are many extreme environments in nature, not all ecosystems have natural origins.

And one of the most unusual ecosystems on Earth is the result of a human-caused catastrophe back in 1986. That year, an explosion at the Chernobyl nuclear power plant released huge amounts of radioactive material across 200 thousand square kilometers in Europe. It was one of the worst environmental disasters in human history, and humans have been evacuated from the 4,000 square kilometers around the power plant for more than 30 years.

This is called the Chernobyl Exclusion Zone, and it is still unsafe for humans to live there. Still, as deadly as the region is, some species actually seem to be thriving inside it. Things haven't gone exactly back to normal.

Even this long after the disaster, mutation rates in animals and plants are really high. Research has also shown that radiation exposure has shrunken the brains of some birds and caused a rise in tumors, fertility issues, and other abnormalities. Parasites may also be using these weaknesses to find new ways to attack their hosts.

So in general, all the major animal groups studied within the Exclusion Zone have declined, including bees, grasshoppers, birds, spiders, and mammals. But in spite of all that, some animals are doing better than you'd think. Some species of birds seem to have responded to high radiation levels by producing higher levels of antioxidants, which help reduce the damage to their DNA.

Weirdly enough, the birds' ability to adapt seems to be tied to their pigmentation; flashier-looking birds seem less able to produce enough antioxidants to protect themselves from the radiation. But it's not just dull birds and parasites that are able to survive under these conditions. Some mammal species are actually more abundant inside the exclusion zone than they are outside.

Scavengers, like wolves and Eurasian otters, seem to be diverse and thriving. And as bizarre as that might sound, the explanation is likely pretty simple:. For some organisms, a radioactive ecosystem is better for survival than one that has humans in it, thanks to the added stress that our presence tends to put on environments.

Even though these radioactive or far-flung ecosystems might not seem especially homey to us, they go to show that life can make a home out of just about anything. Understanding these ecosystems can help us protect or repair them, and it can also help us appreciate how incredibly resilient and creative living things can be. Thank you for watching this episode of SciShow!

And if you liked this video, you might enjoy our episode about the tiny ecosystems hiding inside glaciers. Which just goes to show that life will find a way anywhere if you give it a chance. If you wanna watch that episode, you can right after this. [♪ OUTRO].