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,
与之类似 土壤里还充斥着蜗牛 蚯蚓一类的生物
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.
蟹 蜗牛 帽贝 甚至是食骨蠕虫等动物
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.
巨型管状蠕虫 贻贝 蛤 蟹和虾一类的生物
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.
其他各种生物 如鱼类 磷虾 水母和海鸟
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
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
因此 总的来说 禁区内的
within the Exclusion Zone have declined,
including bees, grasshoppers, birds, spiders, and mammals.
包括蜜蜂 蚱蜢 鸟类 蜘蛛和哺乳动物
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.
这表明了 只要有机会 生活可以在任何地方找到活路
If you wanna watch that episode, you can right after this.