It’s cold, it’s stressful, it’s loud, it’s dark, and only three humans have ever
been there…
where am I thinking of?
Ew.
Get your mind out of the gutter.
Hey there deep divers, Trace here for DNews.
3.5 billion passengers flew on airplanes in 2015, according to the International Civil
Aviation Organization.
Many of those passengers flew at or higher than 36,000 feet or 11 kilometers above sea
level.
Yep, equivalent to half the world’s population went plus 11 last year… how many went minus
11?
How many people EVER have gone 11 kilometers under the ocean?
Three.
Ever.
Jacques Piccard and Don Walsh in 1960, and James Cameron in 2012.
3.5 billion up, three down.
That’s pretty uneven.
We know quite a lot about the world from 11 kilometers (and above), in fact, we know there
are oceans on other planets, but what do we know much about the Mariana Trench -- the
deepest known place on Earth?
The Mariana Trench was discovered by a British Royal Naval vessel, the HMS Challenger during
what is widely considered the first oceanographic expedition in history.
The ship covered about 110,000 kilometers over the 1,000 day voyage from 1872 to ‘76,
and they published their findings in a 29-thousand-five-hundred-page, 50-volume report -- ahem -- 23 years later...
It took a while to put it all together.
Anyway, they took depth measurements (called soundings) throughout their trip around the
globe, discovering the mid-Atlantic ridge (a mountain range in the middle of the Atlantic)
as well as the deepest sounding recorded to that date, southeast of Japan…
Their measurement read 8,184 meters (26,850 ft)!
Over 8 kilometers (5mi)!
If you plopped it down, Everest’s tip would peek above the waves, but they were waaay
off.
Measurements taken in the decades since that first expedition kept pushing the Mariana
lower -- until in 2010 the United States Center for Coastal & Ocean Mapping measured Mariana’s
deepest point -- called Challenger deep -- at about 10,994 meters (36,070 ft)!
This would leave Everest more than 1.6 kilometers (1mi) below the surface of the Pacific.
This 2550-kilometer-long trench, named for the nearby Mariana Islands, was formed by
subduction, meaning one of the tectonic plates that hold the continents of our planet is
dipping beneath the neighboring plate.
This chasm sits under so much water, the pressure is 1,000 times greater than at sea level with
temperatures near freezing.
Plus, light only penetrates a few hundred meters into seawater.
Everything below 1,000 is in the aphotic zone -- no photons.
So, at nearly 11 kilometers it’s darker and colder than you can imagine.
And yet, life abounds…
Down there we’ve found amphipods -- which are related to crustaceans, ranging in size
from thumb-sized to 30 centimeters (1ft)... sea cucumbers -- echinoderms (like starfish
or sea urchins), and microorganisms like foraminifera -- sort of like giant amoebas… they’re
shelled, protists (a Kingdom of life we rarely talk about on DNews).
In fact, a Japanese robotic expedition in 2005 found over 400 species of protists.
According to a super-great SciAm article on Challenger Deep, these xenophyophores use
sand found on the seafloor to construct shells and protect themselves.
In shallower seas they use calcium, but at that depth, the pressure is just too great.
Of course, if bacteria can survive on Mars, then it stands to reason they’re on the
bottom of the ocean too.
Researchers found Proteobacteria, Actinobacteria, Geobacillus, and others.
Each distinct from their surface-dwelling cousins, in that they’d evolved to survive
under the incredible pressure at the bottom of the ocean.
According to a 2013 paper in Nature Geoscience, there may be 10 million microbes per cubic
centimeter in this seafloor sediment!
Not dissimilar to population densities of regular topsoil on the surface.
It’s weird though, I mean, without light or heat, life at this depth is so… alien!
For example, what do these life-forms eat (other than each other)?
We need to visit more…
not just for our curiosity.
In 2012, film director and explorer James Cameron descended at the “amazingly fast”
150m per minute, and became the first human in decades to lay eyes on Challenger deep.
He took samples and recorded the whole thing on video.
On the surface, scientists of all flavors were drooling in jealousy and excitement for
what would be recovered.
Understanding how life can survive in such extreme environments doesn’t just help us
understand the ocean, but LIFE in general!
If we want to look for life on other planets and moons like under the ice sheets of Europa
or Enceladus… we’ll need to understand what we’re looking for.
Science begets science begets curiosity begets exploration.
I love it.
What do you think?
Should we explore the ocean?
Or space?
Want to know more about the oceans orbiting Saturn and Jupiter?
Watch this video, here.
Let us know down in the comments your thoughts and make sure you subscribe for more DNews.