Our Strange World

Why is the Deepest, Darkest Place on Earth so Noisy?

Scientists from NOAA have recently released audio recordings taken from the Mariana Trench, the very deepest part of the ocean. Strangely enough, sounds from humans, animals, and the earth itself can be heard echoing in its dark depths. link

Researchers sunk a hydrophone 36,000 feet into the Challenge Deep in the Mariana Trench in an effort to establish some baseline for oceanic noise. They were, logically, expecting to capture nothing more than silence - given the remoteness of the trench and its depths.

Much to their surprise, over the course of several weeks, they were able to capture whale calls, ship propellers, earthquakes, and the sound of a category four typhoon passing above.

How is this possible?

Well, sound waves travel around 5x faster through water than through air. In addition to the speed, they also have to deal with fewer disturbances and obstacles, which helps them travel further distances.

One of the main reasons NOAA conducted this 23 day study was due to the prevalence of noise pollution. Human generated noise pollution, like ship propellers, have been often linked to disruptions in marine life behavior. At close to the bottom of the Mariana Trench, researchers thought they would be too far away from these disturbances to hear a thing.

There is a return investigation planned for 2017 to see if noise levels have increased.

 

This picture was taken by AvocadoGirlfriend and is licensed under Creative Commons.

Would you still eat if you had to rip open your mouth every time?

Having to completely rip your once sealed mouth every time you want to enjoy a taco seems like a lot of work. But, that's exactly how the hydra consumes most of its meals. The hydra is a small freshwater creature that has to tear its mouth, a sealed (and re-sealing) piece of skin, each time it wants to eat. link

The hydra lack bones, measure less than half an inch, and live underwater. They typically exist attached to an underwater plant stem. Their tubular bodies, which end in tentacles and stingers, are the perfect bio-weapon for spearing microscopic crustaceans and corepods. Eva-Maria Collins, a cell biologist and physicist that led the study comments, "We were really struck by the fact that it can open its mouth wider than its body...nobody actually knows how it achieves this feat".

Through some serious microscope sleuthing, the team realized that the cells are not actually moving relative to each other when it opens its mouth. Instead, each cell keeps its neighbor and both stretch together. The stretching is allowed by the muscle-like cells in the mouth's outer later. The process, they say, is similar to how muscles in the iris of a human eye contract to widen the pupil. Additionally when the researchers decided to add a muscle relaxant to the hydras, they couldn't open their mouths at all!

Biophysicists have jus recently filmed these hydras and their eating process as a hope to finding more clues about tissue regeneration.

This photo is licensed under Wikimedia Commons and Public Domain.

The Ways of the Waterbear

Link At Astonishing Legends, we’re a little more than obsessed with Tardigrades (also known as waterbears). If you’ve ever been to our front page, you’ve probably noticed it. But, now, there’s big news about these little creatures.

For those not yet indoctrinated in the ways of the waterbear, here’s a quick catch-up. They are microscopic animals first discovered in 1773. They have eight legs and are, roughly, 1mm long. Their phylum name “Tardigrada” means “slow stepper”. They populate all the craziest places on earth, from mountaintops to the deepest depths on the ocean.

Now researchers have successfully revived these micro-animals that were kept frozen for over thirty years.

The researchers are Scientists from Japan’s National Institute of Polar Research. They originally gathered the creatures from a moss sample in 1983. The tardigrades have been stored at -4 Fahrenheit ever since. A previous study conducted brought them out of freezing conditions after only 8 years, and it was believed the upper length of survival would be about 10 years.

Two waterbears were resuscitated and, though one died after twenty days, the other reproduced with a third specimen hatched from a frozen egg. It then laid 19 eggs, with 14 successful hatches. So, not only have they revived animals that were frozen for 30+ years…they actually got them to reproduce with relative success.

So, how did they survive? Well, they enter a state called “cryptobiosis” in which their metabolic processes systematically shut down and they show no visible signs of life.

The National Institute of Polar Research is now pursuing this research on the creatures’ genes and its spectacular recovery ability to gain a better understanding of its enviable long-term survival mechanism.

 

This picture was taken by Bob Goldstein and Vicky Madden, UNC Chapel Hill. it is licensed under Creative Commons. You can find more of their work and pictures of tardigrades here.