NARRATOR: At the top of the world, scientists are on a
hunt for a one-of-a-kind time capsule.
BRANWEN: I decided to study the ocean, because I fell in love with it.
NARRATOR: Branwen Williams is an environmental scientist.
She hopes to uncover what our oceans were like long ago.
BRANWEN: We don’t know a lot about the ocean, because in addition to it being really
wide, and covering our Earth from the Tropics all the way up to the Poles,
it’s also really deep, on average, about four kilometers deep.
So there’s a lot of parts of the ocean that we’ve never even seen before.
NARRATOR: Branwen’s mission took her on an adventure to the Arctic Circle.
But what she needed was under the ice.
BRANWEN: We would saw holes in the ice for the diver to go down.
We had a challenging time because water on his dive equipment would actually
freeze, and so then he would have to come back up and we would have to melt that before
he’d go down again.
You don’t actually get a lot of bottom time.
We have about 20 minutes in a dive, and they probably only do two dives a day.
NARRATOR: The time capsule they’re searching for isn’t manmade.
It’s built entirely of algae.
BRANWEN: We were a little concerned that we wouldn’t find the algae.
It was exploration and you don’t know what you’re going to find.
So we were thrilled when on the second day of diving, we were able to find our algae.
NARRATOR: But how do coral and algae reveal the secret history of the ocean?
For that, Branwen heads back to her lab in sunny California.
BRANWEN: We cut the specimen in half using a saw, and then we can get an idea of what the
growth pattern is and how old the specimen might be.
Just like trees on land, plants and animals in the oceans capture changes in the
environment in their skeletons.
We can actually measure the growth each year in the algae, and that can give us an idea of
how much sea ice there’s been in the Arctic, from year-to-year.
In years where it’s warmer, there’s less sea ice.
And so there’s more light being able to reach the algae on the seafloor.
And years when it’s cooler, there’s more sea ice, and so there’s less light reaching
the sea floor.
NARRATOR: The wider the rings, the warmer the planet was that year.
BRANWEN: We can learn a lot from the organisms,
from the plants and animals that live in the oceans.
Sea anemones there.
It’s really amazing, because these organisms, plants like the algae or animals like
corals, they are actually growing and documenting changes in the environment.
NARRATOR: Branwen’s hard work shows us how our climate has changed over hundreds of
years, and how people are causing that change.
BRANWEN: To me, a healthy ocean is an ocean that provides for everything that
depends on it, for all the plants and animals that live in the ocean and all the
things that live on the land that rely on the ocean.
The changes that we’re seeing in the climate, they’re largely caused by people’s activities.
And what that means, though, is if people are causing these changes in climate,
it means that we can do something about it.
