The most extreme life on Earth part three: the great deep sea farmers

In the abyss of the deep, vents provide energy for an oasis of incredible and bizarre life.

The bottom of our oceans are a black expanse of nothingness for hundreds of kilometers in each direction. Yet in the darkness of the deep sea desert, hydrothermal vents provide a spectacular oasis, as densely populated as most ecosystems on land, boasting an array of the strangest animals on the planet.

In the deep abyss, you have to deal with crushingly high pressures, low and high temperatures but most of all, an absence of energy. About a kilometre down there is no light and without photosynthesis, or basically anything else, finding an energy source is like finding a needle in a haystack.

The vents provide energy by constantly pumping superheated water (up to 400oC, as at high pressures the boiling point of water increases), which have previously gathered minerals in the rock below.

Large animals can’t use this chemical energy directly, but incredibly they literally farm microbes which can.

Tube worms (above and below) can grow to a massive 3 meters long, and they are gross. Perhaps the weirdest thing about them isn’t the fact that they look like a garden worm on steroids, but that they don’t have an anus. Instead, they gather their excrement in a sac, which slowly fills up and poisons them until they die. More remarkable still, their farming of microbes has gone so far that they have replaced their digestive tract with their livestock. Infact, half of the body weight of a tube worm is pure microbes, constantly using the hydrogen sulphide to provide the worm with energy.

The tube worm outside its shell showing the sac which slowly fills up with its own excrement.

Pompeii worms are equally as bizarre, but farm their microbes in a more traditional sense (kind of). They harbour the livestock on their back, let them grow and then let other worms feed on them. Vent shrimps do something similar, growing microbes on their body, but instead of letting others harvest them, they wait until they shed their skin, and then eat their old carcass.

A Pompeii worm

Considering these crazy creatures have been farming for millions of years, and we only started 12,000 years ago, maybe they’ve beaten us other things? If we look further maybe they’ve got little cars and record players, and are studying humans in tiny, deep sea laboratories.

The most extreme life on the planet part two: living for 250 million years.

Could a microbe (arrow) live inside a salt crystal for 250million years?

On the turn of the millennia, Russell Vreeland released an incredibly controversial paper, in which he claimed they had found a microbe that had been alive for 250 million years. That’s your life, 30000000 times. More remarkable still, the microbe had survived inside a salt crystal (above).

Originally, it was received with a great deal of caution in the scientific community, as no-one thought life could persist that long, even if in suspended animation, let alone active and growing. After all, how do you get energy to grow for a quarter of a billion years?

Since then, another scientist, Brian Schubert, devised a more robust experiment, suggesting that microbes can live off the glycerol produced by just one cell of green algae for 12.5 million years. The glycerol would provide energy for cell repair whilst preventing dehydration and protein damage.

It is not beyond the realms of possibility then, that life could persist for 250 million years, or even longer. Could Vreeland have been right all along? In a booming scientific field, the race is on to find out.

Extreme life part one: volcanoes:‎(opens in a new tab)

To understand how long 250 million years read: Feel old yet? Understanding just how ancient Earth is:‎(opens in a new tab)

How do we know how Dinosaurs Behaved?

All movie and picture book dinosaurs paint a clear picture of dinosaur behaviour in our heads. The T. rex a big mean eating machine and the diplodocus a painfully slow giant that laboriously grinds the leaves of tall trees.

Remarkably, 99.9% of the time all our information comes from a single bone. Making conclusions is like guessing the picture of a 1000 piece jigsaw after only completing the border.

So how do they do it? Paleontologist Michael Benton explains three ways…

The first is to look at modern animals and compare. Simply, living animals with sharp teeth are almost always predators, therefore a dinosaur fossil with sharp teeth is probably a predator.

Second, observe the closest living relatives to dinosaurs, crocodiles and birds. For example, it is safe to say the T. rex had eyes of some description, as both crocodiles and birds also have eyes.

Lastly, using biomechanical modelling. Michael found the muscle power needed for the T. rex to run 42MPH, as previously thought, would be like a 6 tonne, T. rex sized chicken with 5 tonne legs. 42MPH it seems, is a wild overestimate.

I’m not going to try and understand how Michael can tell so much from a couple of bones, but either way, a 6 tonne chicken is a pretty scary thought.

How Slobber is the Moose’s Secret Weapon.

Ever tried dribbling on your meal?
It may seem bizarre, but researchers have recently revealed that moose do exactly that to protect themselves from plant defences.

After reading about how moose drool on a half eaten twig can cause re-sprouting, David Tanentzap from the University of Cambridge began to wonder whether this slobber has any other uses.

David explains how grasses release toxins that make moose sick to deter them from grazing. By slobbering over their future snack, moose can turn off plant defences to ensure a safe meal.

After somehow convincing zookeepers to do all the dirty work and scoop up moose drool after medical procedures, the scientists dabbed the saliva onto grass and watched the results.

Astonishingly, the spit did prevent some grasses from releasing toxic substances. However, rather perplexingly, the effects were only seen after a long time, meaning that slobbering over grass is only useful if the moose return to the same patch of grass later.

David is excited for future research to shed light on whether the moose do in fact return to the same patches of grass to make use of this remarkable, if a bit gross, ability.