Four things we (still) don’t know about the ocean

Humpback whale
Humpback whale| Image: SZakharov/Shutterstock

Whilst the Kraken may not exist, there are still plenty that’s unknown to us about the deepest reaches of the ocean and the creatures that make it their domain…

Why aren’t blue whales singing like they used to?

The fact that whales communicate via song-like vocalisations has been understood for decades. Even if we don’t know what they’re saying, they are communicating.

But a mystery has emerged, blue whales are now changing the way they communicate. Specifically, their vocalisations have become notably lower in pitch—but researchers don’t have a definitive answer as to why.

One of the possible reasons is that human activity in the ocean has created an unnatural level of noise pollution. Global warming also means that as oceans warm they hold on to less oxygen. More carbon dioxide in the water means that normal whale sound is travelling less far, so the whales are resorting to lower wavelengths to get there.

Greenland shark
Greenland shark | Image: Planetfelicity

What’s the deal with Greenland sharks?

Perhaps the most intriguing thing about Greenland sharks is their incredible lifespan. These creatures can live as long as 400 years, maybe longer.

Scientists were able to determine this several years ago by dating proteins from the sharks’ eyes but what they don’t know for sure is how they’re able to live as long as they do. It’s possible that it’s down to their hearts, which beat much more slowly than a human heart. It might also have to do with their unique, ancient immune system.

You’d think that, based on their name, Greenland sharks would be solely found in frigid, arctic waters. It’s very possible that Greenland sharks live just about anywhere on the planet, but because humans rarely dive deep enough to run into them it’s extremely difficult to confirm beyond the occasional rare sighting.

A mysterious purple orb found at the bottom of the Pacific Ocean by NOAA scientists
A mysterious purple orb found at the bottom of the Pacific Ocean by NOAA scientists onboard the Nautilus research vessel | Image: © NOAA

What’s that blob..?

It’s not unusual for new ocean-life to be discovered. In fact, it’s, paradoxically, fairly common. But few discoveries are as immediately striking as the purple orb that was discovered in an underwater canyon off the coast of Catalina Island by the team aboard the Exploration Vessel Nautilus.

In the discovery footage, light from the camera gives it an incredible, purple glow that makes the sphere look less like a sea creature and more like a video game powering up.

‘The blob’ was initially thought that it was some type of mollusc or sea slug but, after research was conducted on the specimen by the Harvard University Museum of Comparative Zoology, it appears likely that the sphere is a type of snail.

Light streaming into an ocean cave
Image: HIN-db/Shutterstock

What does 81% of the ocean floor look like?

Though we’ve been able to fully map the surface of the moon, a complete topographical image of what the planet’s ocean floor looks like is still something of an unknown.

Though researchers have recently made progress in this area, as recently as 2017 only 6% of the ocean floor had been mapped. But, thanks to the Nippon Foundation-GEBCO Seabed 2030 Project, we can now say that 19% of the ocean floor has been surveyed.

Map of the world illustrating where where we still need modern measurements at a reasonable resolution.
The black is where we still need modern measurements at a reasonable resolution.

That just leaves researchers to survey an area that project director Jamie McMichael-Phillips described to BBC News as “twice the size of Mars.” This knowledge isn’t just a matter of ticking off a box, as understanding what the ocean floor looks like and how it affects the atmosphere is an element of combating climate change.


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