This time on Jonathan Bird’s Blue World, Jonathan investigates what might be the clearest
water in the world!
Hi I’m Jonathan Bird and welcome to my world!
Scuba divers crave clear water.
Good visibility makes diving more like flying, being able to see your surroundings from above.
Humans are visually oriented.
We like being able to see what’s going on around us, and clear water allows us to keep
a safe distance from something like feeding sharks, but still see the action.
Temperate water is rarely very clear.
We consider ourselves lucky to get 30 feet of visibility in New England.
Sometimes it’s not even that good—more like 10 feet.
You can barely see anything until you are right on top of it.
Plankton makes this water extremely fertile, but you can’t see through it very well.
In the tropics, water has less plankton and it’s often quite a bit clearer.
It’s not unusual to have 100 feet, sometimes even 150 feet of visibility in the tropics.
At the massive Neutral Buoyancy Lab in Houston—a huge indoor swimming pool where astronauts
are trained—I have experienced visibility of at least 400 feet.
The water is so clear, it’s like it’s not there at all.
But this is a pool.
The water is filtered and chlorinated.
Is there anyplace in the world with naturally-occurring clarity like this?
To find out, I have come to Iceland.
To a place called Silfra.
Iceland is right smack-dab in the middle of the mid-Atlantic ridge, where two large tectonic
plates meet.
Lava coming out from between these plates at a hot spot created Iceland about 20 million
years ago.
But since those tectonic plates are still moving, Iceland has cracks down the middle
and occasional earthquakes as a result.
This is one of the few places in the world where you can actually see the crack between
two tectonic plates!
Silfra is one of those cracks.
It has filled with spring water that percolates up through the ground from distant glaciers.
So it’s cold and it’s clear.
Iceland itself is a beautiful and sparsely populated country full of natural wonders.
It has huge glaciers.
And those glaciers give birth to icebergs which float away into the North Atlantic ocean.
But even though it’s called Iceland, it’s not all ice by any means.
At least in the summer.
There aren’t many trees, but the landscape features rolling green grassy hills.
There are grazing sheep.
And lots of farms.
Summer meltwater feeds scores of rivers and streams.
Some are crystal clear, others are filled with minerals making them milky white.
And there are waterfalls.
I mean a lot of awesome waterfalls!
This is Gulfoss, one of Iceland’s largest.
Until recently, the only divers who came here were animals.
But Silfra has changed all that.
Divers now come from around the world to experience the amazing visibility in this tiny dive site
just a few meters wide and a few hundred meters long.
They say this is the clearest water in the world.
Let’s go find out!
My adventure begins in downtown Reykjavic, Iceland’s capital city.
I head on over to Dive Iceland to sign up for one of their all-inclusive Silfra dives.
The next morning at the crack of dawn, I head over to the dive site.
We’re meeting early so we can have the whole place to ourselves.
Christine, Cameraman Todd and I meet up with our divemaster, Jose Soroa, who gives us a
basic introduction to the area and how we will conduct the dive.
We take a walk all the way around the site.
Diving here is not without difficulty.
I’ll need a dry suit to stay warm in the water which is barely above freezing.
Since most people don’t go to Iceland specifically to dive, they often don’t bring any gear.
Dive Iceland supplies everything you need, even the dry suit.
Our team has decided to try their gear, for the full experience.
So we’re all getting into drysuits we’ve never worn before.
After we have our suits on, I have to carry my camera all the way from the parking area
to the entry point.
They could have put the parking area a little closer!
It takes us a few more minutes to get the rest of the gear on, and then we hoof it over
to the entry.
Fortunately, the entry is easy.
There’s a nice staircase right down to the water.
Jose hands me my camera and I sink down into clear, cold water.
While I get my gear adjusted, Christine and Todd climb carefully down the steps to join
me.
Under the surface, there is nothing to see but bare rock—and crystal clear water.
My first view under the surface blows my mind—I can see all the way down to the end of the
crack where it takes a turn!
I have no idea how far that is.
Once everyone is ready, we submerge.
Then Jose leads the way downstream.
There’s a gentle current in Silfra from the spring opening all the way down to a lake.
The incredible visibility is no exaggeration!
This is the clearest water I have ever seen in sunlight.
The straight sections of Silfra aren’t even long enough to test the full visibility, but
it’s easily many hundreds of feet.
We swim for a few minutes through a narrow crack, which is at least 50 feet deep.
There’s nothing to see down there, so we stay pretty shallow where the marginal morning
light is a little better.
Then we have to cross a shallow area to keep going.
In places it’s only two feet deep!
I could get up and walk!
I have no idea where we are heading but I follow Jose because he has done this dive
several hundred times.
In this shallow water, strands of green algae thrive on the ample summer sunlight.
After passing through the shallow section, we head into another deep crack.
Now that the initial excitement has worn off, I’m noticing the water temperature, which
is only 36° Fahrenheit, barely above freezing.
My face is completely numb.
This water is nearly as cold as the water in Antarctica!
It might look tropical because of that blue color seen in very clear water, but I’m
definitely not in the Bahamas.
I’m not going to let the cold keep me from having some fun though!
There might not be much to see, but I can always use some nice clear water to practice
blowing bubble rings.
But it’s not easy with a tight hood and numb lips!
Everyone is getting pretty cold, so we continue on.
If we want to get out of this water, we need to make it to the exit point, so we have some
more swimming to do.
At the end of the second section of deep water, there is a wonderful sandy slope leading back
to the shallows.
We swim up it, expecting the water to get warmer as we swim towards the sun, but alas
there’s no thermocline.
It’s just as cold at the top!
We emerge up into what looks like a small pond.
The pond is actually an inlet from a huge lake.
Once the water goes out into the lake, it loses its clarity.
But here in this pond-like section, we get our chance to see a long way underwater in
a straight line.
Finally we can see the steps for the exit, and we swim over, with our fingers and toes
totally numb.
I have one last look at the amazing visibility and climb out.
Woo!
That was great!
But man is it cold!
I can’t feel my thumbs!
So I traveled all the way to Iceland to dive in a crack in the ground to see some rocks
and algae.
This much is true.
But I had to see for myself the spectacle of such clear water.
The water at Silfra comes out of the ground as the purest glacial meltwater--with no plankton
to reduce its clarity.
For a few hundred meters it travels down the crack between tectonic plates towards a lake,
where it will mix with lakewater.
For that short distance, divers have the chance to experience something like flying, in water
so clear, it’s like air.