Update: November 7, 2007

ICE FREE ARCTIC, PLANTS & BUGS

By Pam Eastlick for THE DEEP on line

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.

NOT NEARLY CHILLING ENOUGH!
Our first story is another chiller from the poles.  And the bad news is that they aren’t nearly as chilly as they used to be.  Scientists have announced that Arctic sea levels have fallen 50% since the 1950’s.
The size of the north polar ice cap in September of this year was 1.65 million square miles, the lowest September on record, shattering the previous record for the month by 23 percent, which was set in 2005.  At the end of the melt season, September 2007 sea ice was 39 percent below the long-term average from 1979 to 2000.

If ship and aircraft records from before the satellite era are taken into account, sea ice may have fallen by as much as 50 percent from the 1950s.  The September rate of sea ice decline since 1979 is now more than 10 percent per decade.

Arctic sea ice receded so much that the fabled Northwest Passage completely opened for the first time in human memory.  Explorers and other seafarers have long recognized that this passage, through the straits of the Canadian Arctic Archipelago, represents a potential shortcut from the Pacific to the Atlantic.

Roald Amundsen began the first successful navigation of the route starting in 1903.  He and his men took two-and-a-half years to leapfrog through narrow passages of open water, with their ship locked in the frozen ice through two cold, dark winters.  More recently, icebreakers and ice-strengthened ships have on occasion traversed the normally ice-choked route.

However, by the end of the 2007 melt season, a standard ocean-going vessel could have sailed smoothly through.  On the other hand, the Northern Sea Route, a shortcut along the Eurasian coast that is often at least partially open, was completely blocked by a band of ice this year.

Changes in sea ice extent, timing, ice thickness and seasonal fluctuations are already having an impact on the people, plants, and animals that live in the Arctic.  Researchers fear that the sea ice cover is in a downward spiral and may have passed the point of no return.  As the years go by, Mother Earth is losing more and more ice in summer, and growing back less and less ice in winter.

They also say we may see an ice-free Arctic Ocean in summer within our lifetimes.  Now that’s a chilling statement!

And now let’s leave the land of ice and snow and go to visit the plants.  It turns out they aren’t nearly as boring as you thought they were!

DO YOU TALK TO YOUR PLANTS?  GUESS WHAT?
Research conducted recently in the Netherlands has shown that plants have their own communications systems they use to warn each other about predators.  This certainly flies in the face of conventional wisdom that plants are boring and passive organisms.  Many plants form internal communications networks and can exchange information efficiently.

Many herbaceous plants like strawberries, clover, reeds and ground elder naturally form networks.  Individual plants remain connected with each other by means of runners or underground roots. These connections allow plants to share information with each other like computer networks. But what do plants have to chat about?

The Dutch researchers have demonstrated that clover plants warn each other via their linked runners if enemies are nearby.  If caterpillars attack one of the plants, it sends a chemical message to the other members of the network.  Once warned, the intact plants strengthen their chemical and mechanical resistance so that they are less attractive for advancing caterpillars.

I’ve always suspected that there’s more to plants than meets the eye!  And now for a story about a plant with a strange method of reproduction.

MOTHER OF THOUSANDS Plant lovers and scientists alike have long been fascinated by a species of the common houseplant Kalanchoe.  The common name for the plant is “Mother of Thousands” and the plant doesn’t flower nor does it set seed.  Instead Mother of Thousands makes many tiny plantlets that drop from the edges of its leaves. Many plants reproduce by throwing out long shoots or runners that can grow into new plants.  But Mother of Thousands goes further: the plantlets are complete miniature plants that become disconnected from the mother plant's circulatory system and drop off, allowing them to spread rapidly and effectively.  The houseplant has lost the ability to make viable seeds and only reproduces through plantlets.

The houseplant "mother of thousands" makes the tiny plantlets that drop from the edges of its leaves. (Credit: Neelima Sinha/UC Davis photo)

Researchers have identified a specific gene that most plants use to make seeds.  They discovered this same gene in the leaves of the Mother of Thousands plant.  Mother of Thousands appears to have lost the ability to reproduce sexually and make seeds, but transferred at least part of the embryo-making process to the leaves to make plantlets.  These findings could be useful in manipulating plant reproduction.

And how can you talk about plants without talking about the insects that eat them and fertilize them?

IF YOU CAN’T DECOMPOSE IT, EAT IT!
Farmers in Australia have been mystified for years about what’s been causing their drip irrigation pipes to leak.  These farmers were irrigating their hay crops with small thin-walled plastic pipes that were buried underground.  They had been experiencing water leaks caused by hundreds of tiny 1 to 2 millimeter holes.

There were many suspects.  Ants, African black beetles, crickets, mice and physical wearing of the plastic piping had all been blamed but laboratory experiments have confirmed the culprit is the larvae of the Whitefringed weevil.

Because the affected pipes are buried underground, growers have to take an educated guess about the location of the holes.  They seek out the areas where the plants are especially lush and dig down to make repairs. The problem is that they have to track down all the holes in the irrigation pipe to restore water pressure, and ensure the even distribution of water throughout the irrigation system.

So . . . . does this larva eat plastic or just chew holes in it?  If it actually eats the plastic, we may have found a solution to something else besides what’s causing the holes in the irrigation pipes!

TARTIGRADES IN SPACE
We all know that we’ve had many animals in space.  The first living creature in space was Laika the dog and since then there have been chimpanzees, spiders, earthworms and mice to name only a few.
However, all the animals (including the humans) that have visited outer space have actually been in an enclosed capsule that maintained their Earth environment.  Now, for the first time; we have animals being exposed to SPACE with both vacuum conditions and cosmic radiation.  We have sent in the tardigrades.

Tardigrades are seriously cool, almost microscopic animals.  Their common name is ‘water bears’ and anyone who’s spent anytime peering through a microscope or dissecting scope has probably seen one lumbering along.  If you want to know what one looks like, just imagine the map of Saipan.  Saipan’s outline looks very much like a tardigrade.

Tardigrades may also be the hardiest animals on the planet.  Although they average only 1 millimeter long, they can survive extreme environments that would kill almost any other animal, including extreme heat (up to 300F) and temperatures close to absolute zero.

Their resilience lies in their ability to enter a dry dormant state where they replace almost all the water in their bodies with a type of sugar.  They can stay like this for at least 10 years and return to normal with just a drop of water.  When they are desiccated, they can escape many things that would ordinarily kill them.  Environmental agents that rely on water or the respiratory system don't work.  You can put a dry tardigrade in pure alcohol and expose them to poisonous gases without killing them.

The space-faring tardigrades were loaded onto a satellite last month in the desiccated state.  All their sample containers had ventilation holes to allow the vacuum of space to penetrate inside, meaning they were exposed to solar radiation, galactic cosmic radiation, and weightlessness.

Since their return last week, they’ve been placed back in water to see if they recover and if they can reproduce as well as individuals that stayed on the ground.  The researchers will also be examining the water bears’ DNA for damage.  Extensive DNA damage can kill living cells, but even in their hydrated state, tardigrades can tolerate 300 times more radiation than humans can. Exposing organisms to the space environment provides us with knowledge of how living cells are impacted by the stress factors out there.  And the few groups of animals that have the potential to get through a space journey alive will constitute a key source of knowledge when the time comes to create ecosystems in space.

A dehydrated tardigrade