the-BA : Alien Ecosystem

A potential alien ecosystem? (illustrated by Julian Hume)

“Is there life on other planets?” is one of the most popular questions posted by the public on The Big Question Blog, part of National Science and Engineering Week.

To help answer the question ahead of a webcast from Jodrell Bank Observatory astronomers this Friday, a group of leading scientists from institutions around the UK have created a spectacular vision of a dark underwater alien world full of glowing jelly creatures including:

• a fibre optic coral reef
• giant jelly whales
• torpedo jelly predators
• ice spiders

Roland Jackson, Chief Executive of the BA (British Association for the Advancement of Science), which coordinates National Science and Engineering Week, said:

“Talking about space exploration and the search for extra-terrestrial life remains one of the most powerful ways to get people hooked on science.

“During National Science and Engineering Week we wanted to give scientists the opportunity to share a possible vision with the public that was based on science not science-fiction.”

Read on to find out about the scientists' vision of alien underwater life...

Where could these aliens exist?

The alien underwater world is based on a planet with conditions similar to Europa, the large moon of Jupiter.

Scientists think Europa could have a deep liquid ocean under a thick crust of frozen ice that appears to have giant cracks across the surface.

Although it is possible that there may be life on Europa itself, scientists have discovered many large gas-giant planets orbiting other stars leading to the possibility of many Europa-like worlds on which life may have evolved. Some of these will be closer to their parent star and conditions may therefore be more hospitable to life than on the Europa we know.

What is our alien environment like?

There are several possible sources of energy for our large, dark saltwater ocean - sunlight for photosynthesis (we have assumed there are areas of thin as well as thick ice where a little light can penetrate) and heating of the core and ocean from tidal flexing and radioactivity.

There are two building blocks for life - colonies of organisms that feed off the material from the radioactive crust and organisms living and growing on the underside of the ice.

These small organisms support a food chain including larger creatures in the same way that Krill support whales.

A Fibre Optic Coral-Like Reef

Where the ice is thin simple organisms in the ocean could use the light and try and maximise the light they could capture by boring up into the ice.

Closer to the surface, these simple organisms might be able to produce something like a light-pipe – they would secrete a silicate substance that would coat the inside of the microscopic ice tube so that it acts like a glassy light pipe feeding light down to the ocean.

Together these networks of light pipes would create a fibre optic coral like formation on the surface of the ice.

Subaquatic Termite Mounds

The scientists proposed that tiny multi-cellular creatures lived in this alien ecosystem and like all the other alien creatures in our underwater world they can use their alien body biochemistry to manipulate the salinity levels of the water and make microscopic bits of water freeze.

These aliens could also display all the characteristics of swarm intelligence (like termites or other social insects on earth).

So the collective behaviour of millions of these relatively simple creatures freezing microscopic bits of water would create ice-structures projecting down into the water from the underside of the planet's ice crust .

The reason that tiny specs of light are seen shining from the underside of the ice-mounds is that the ice-mound might contain ‘gardens’ in which the simpler fibre-optic coral-reef organisms become food producers for the ice-mound creatures.

Giant Jelly Whales

The creatures at the top of the food chain would be giant soft skinned creatures – something like a vast jelly fish combined with a baleen whale cruising the waters like a submarine hoovering up smaller organisms.

These jelly creatures would slowly cruise the deeps, and because their density is more or less the same as the water they have no problem at all moving between different depths.

They would have a ‘jet’ propulsion system a feature found on many creatures on earth.

A lot of jelly creatures are jet propelled but all the ones on earth are relatively inefficient because they suck water from the back and squirt it out the back. A more efficient method would be to take water in from the front and squirt it out the back.

In an underwater ecosystem where these giant jelly whales were dominant it’s not beyond the realms of possibility that they could also use their propulsion system as a way of feeding.

Torpedo Jelly Predators

The Torpedo Jelly Predators are a higher performance version of the Giant Jelly Whales. Any creature as big as our jelly whales would be a target for predators.

The Torpedo has a soft jelly-like body – with ice teeth so that it can bore into the whale. It would be an effective way of swimming through the whale and extracting their food en route. Ice teeth are possible because we assume the water is very cold and only just above the freezing temperature of fresh water – so the creature could develop localised freezing.

Of course the torpedo jelly predators couldn't kill the jelly whale easily; the density of the jelly whale is so low that the jelly torpedo would bore straight through, so the jelly whale would be scarred by many such bore holes.

The jelly whales would however have distributed nervous systems with multiple ganglia and sense organs (like earth's jelly fish), which would be higher density protein and hence especially tasty for the torpedo jelly predators. If enough jelly predators ate enough of these parts then the jelly whale could eventually be killed.

Ice Spiders

One of the things that organisms are very good at is controlling the salt in fluid. Because saltwater freezes at a lower temperature than pure water in the case of our Ice Spiders it would be relatively easy for the organism to make the water inside it’s jelly skin have low salt content and therefore slightly higher freezing temperature. So it could therefore have a skeleton made of ice.

The Ice Spiders could be frozen to the under surface of the ice by exuding pure water which would freeze on contact with the slightly cooler exterior. Because organisms generate heat by the bio-chemical processes in their cells – it would be possible for the Ice Spider to generate localized heat so it could freeze and unfreeze and move along the underside of the ice to feed.

National Science and Engineering Week event:

Is there life on other planets?

Find out how astronomy is involved in the search for life on other planets by tuning into a webcast from astronomers at Jodrell Bank on Friday 14 March.

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