by neufer » Fri May 30, 2008 1:37 pm
Dr. Skeptic wrote:Javachip wrote:If we're looking for ice, then why did we decide to land on red dirt again?
Why didn't we aim for the bright, white, crusty stuff that we can see from Earth on the Martian poles?
New white ice has a far less chance of having organic molecules trapped inside than the dirty ice they landed on.
There should less than a centimeter of "Red Dirt" atop dirty ice, "frozen mud" (or permafrost).
Organic molecules are the goal of the mission not the H2O.
- http://library.thinkquest.org/26442/htm ... plant.html
<<The extreme conditions make Antarctica a habitat in which only the hardiest can
survive. Very few species have been recorded on the 2% of the continent that is
ice-free. They include about 150 lichens, 30 mosses, some fungi and one liverwort.
Only two native vascular plants, the Antarctic hair grass Deschampsia antarctica and
a cushion-forming pearlwort, Colobanthus quitensis, survive south of 56°S. They occur
in small clumps near the shore of the west coast of Antarctic Peninsula. This is in
marked contrast to the Arctic regions where nearly 100 flowering plants are found
at 84°N. Both plants can tolerate very cold and dry conditions. They continue to
function at freezing point, when the rate at which they convert sunlight into
chemical energy drops to about 30 to 40 per cent of that reached
during the most favourable conditions.
Lichens
Of all the plants, lichens are best adapted to survive in the harsh polar climate.
Some lichens have even been found only about 400 km from the South Pole. Lichens
have proliferated in Antarctica mainly because there is little competition from
mosses or flowering plants and because of their high tolerance of drought and cold.
The peculiarity of lichens is that they are not one homogeneous organism but a
symbiosis of two different partners, a fungus and an alga. The fungus part supplies
the plant with water and nutritious salt, meanwhile the alga part organic substance,
like carbohydrate produce. With this ideal "job-sharing", lichens can survive the
hardest conditions. Far from the border of highly developed plants, lichens are the
pioneers of the vegetation. Lichens aren’t only frugal and robust, they jug out
because of their very low sensibility against frost. Some lichens, in an experiment,
survived a bath in liquid nitrogen at minus 195 degrees. On icy rock, lichens have
the same strategy as plants have developed in the sand of the Sahara: they form an
"oasis". Like in the desert they miss water. They have only a chance to survive, if
they settle in an area with a convenient, damp microclimate. Since what stops lichens
to spread over the whole of Antarctica is not so much the big cold as the lack of
water. For this reason they don’t settle in a place with the most sunshine, but in
recesses and cracks between rocks. They like scanty soils, created by weathered
rocks. They often quicken this process with secretion of acid.
Snowflake are captured in the cracked rock and smelt on the dark lichens, they can
absorb the vitally liquid. Especially unfavourable conditions are in the "dry valley"
of East Antarctica, where big coldness and low snowfall meet. But even there
scientists have found a dark cover on the north side of some rocks, which prove to
be lichens. Under the microscope it was shown that the lichens penetrate the upper
coat of the rock. With the dark colour the lichens absorb more light. This strategy
enables the lichens to scrape a humble living in those quite high southern latitude.
An often seen lichen is Usnea sphacelata, which looks like a small forest of bonsai.
They even grow on a height of some centimetres. They can only grow on about 120 day
per year, so they only grow between 0.01 and 1 millimetre per year. But they live
very long: an age of 200 years is not unusual, the record is about 4500 years.
Mosses
Only a small number of moss species are found in Antarctica. Extensive fields occur
in a few places on this continent and these are rarely more than 100 mm deep, even in
the most favourable areas where there is shelter and plenty of water. Short moss turf
and cushion moss is found most frequently in sandy and gravelly soils. No extensive
peat formations are to be found. Mosses, like lichens, gather in colonies which make
them possible to collect and retain more water. They also lose less by evaporation
and show a marked ability to use water rapidly whenever it becomes available. Mosses
have also become well adapted to the almost continuous light during the long days
of a polar summer. One Antarctic moss, Bryum argenteum, produces more energy by
photosynthesis in low light at 5°C than it does at 15°C, or higher. Photosynthesis
can start within a few hours of thawing after a prolonged period of freezing,
and almost immediately following short periods.
Algae
More than 300 species of non-marine algae have been found in Antarctica. These very
simple plants take many diverse forms and a few have become adapted to living in
difficult polar environments. Blue-green and other algae are found growing in damp
sand and gravel around lakes and tarns, along meltwater streams or in low-lying
areas, where snowdrifts or seepage may collect. Some such as Prasiola crispa can
tolerate high levels of nutrients and are found near bird colonies. Others – the
snow algae - may form extensive and spectacular red, yellow or green patches in
areas of permanent snow. Recent studies have shown that some blue-green algae
live inside rocks in dry valleys. Commonly they are found under stones,
particularly light-coloured quartz stones, where the microclimate is more
favourable than in the surrounding sand or soil. Together with lichens,
they are the only living things in a barren landscape.
Fungi
Fungi have been studied little. Several mushrooms have been found on the west coast
of the Antarctic Peninsula, and on the South Shetland Islands. A few of the fungi
found in Antarctica are unique to the continent. The majority, however, are also
found in most temperate areas>>
[quote="Dr. Skeptic"][quote="Javachip"]If we're looking for ice, then why did we decide to land on red dirt again?
Why didn't we aim for the bright, white, crusty stuff that we can see from Earth on the Martian poles?[/quote]
New white ice has a far less chance of having organic molecules trapped inside than the dirty ice they landed on.
There should less than a centimeter of "Red Dirt" atop dirty ice, "frozen mud" (or permafrost).
Organic molecules are the goal of the mission not the H2O.[/quote]
[list]http://library.thinkquest.org/26442/html/life/plant.html
<<The extreme conditions make Antarctica a habitat in which only the hardiest can
survive. Very few species have been recorded on the 2% of the continent that is
ice-free. They include about 150 lichens, 30 mosses, some fungi and one liverwort.
Only two native vascular plants, the Antarctic hair grass Deschampsia antarctica and
a cushion-forming pearlwort, Colobanthus quitensis, survive south of 56°S. They occur
in small clumps near the shore of the west coast of Antarctic Peninsula. This is in
marked contrast to the Arctic regions where nearly 100 flowering plants are found
at 84°N. Both plants can tolerate very cold and dry conditions. They continue to
function at freezing point, when the rate at which they convert sunlight into
chemical energy drops to about 30 to 40 per cent of that reached
during the most favourable conditions.
Lichens
Of all the plants, lichens are best adapted to survive in the harsh polar climate.
Some lichens have even been found only about 400 km from the South Pole. Lichens
have proliferated in Antarctica mainly because there is little competition from
mosses or flowering plants and because of their high tolerance of drought and cold.
The peculiarity of lichens is that they are not one homogeneous organism but a
symbiosis of two different partners, a fungus and an alga. The fungus part supplies
the plant with water and nutritious salt, meanwhile the alga part organic substance,
like carbohydrate produce. With this ideal "job-sharing", lichens can survive the
hardest conditions. Far from the border of highly developed plants, lichens are the
pioneers of the vegetation. Lichens aren’t only frugal and robust, they jug out
because of their very low sensibility against frost. Some lichens, in an experiment,
survived a bath in liquid nitrogen at minus 195 degrees. On icy rock, lichens have
the same strategy as plants have developed in the sand of the Sahara: they form an
"oasis". Like in the desert they miss water. They have only a chance to survive, if
they settle in an area with a convenient, damp microclimate. Since what stops lichens
to spread over the whole of Antarctica is not so much the big cold as the lack of
water. For this reason they don’t settle in a place with the most sunshine, but in
recesses and cracks between rocks. They like scanty soils, created by weathered
rocks. They often quicken this process with secretion of acid.
Snowflake are captured in the cracked rock and smelt on the dark lichens, they can
absorb the vitally liquid. Especially unfavourable conditions are in the "dry valley"
of East Antarctica, where big coldness and low snowfall meet. But even there
scientists have found a dark cover on the north side of some rocks, which prove to
be lichens. Under the microscope it was shown that the lichens penetrate the upper
coat of the rock. With the dark colour the lichens absorb more light. This strategy
enables the lichens to scrape a humble living in those quite high southern latitude.
An often seen lichen is Usnea sphacelata, which looks like a small forest of bonsai.
They even grow on a height of some centimetres. They can only grow on about 120 day
per year, so they only grow between 0.01 and 1 millimetre per year. But they live
very long: an age of 200 years is not unusual, the record is about 4500 years.
Mosses
Only a small number of moss species are found in Antarctica. Extensive fields occur
in a few places on this continent and these are rarely more than 100 mm deep, even in
the most favourable areas where there is shelter and plenty of water. Short moss turf
and cushion moss is found most frequently in sandy and gravelly soils. No extensive
peat formations are to be found. Mosses, like lichens, gather in colonies which make
them possible to collect and retain more water. They also lose less by evaporation
and show a marked ability to use water rapidly whenever it becomes available. Mosses
have also become well adapted to the almost continuous light during the long days
of a polar summer. One Antarctic moss, Bryum argenteum, produces more energy by
photosynthesis in low light at 5°C than it does at 15°C, or higher. Photosynthesis
can start within a few hours of thawing after a prolonged period of freezing,
and almost immediately following short periods.
Algae
More than 300 species of non-marine algae have been found in Antarctica. These very
simple plants take many diverse forms and a few have become adapted to living in
difficult polar environments. Blue-green and other algae are found growing in damp
sand and gravel around lakes and tarns, along meltwater streams or in low-lying
areas, where snowdrifts or seepage may collect. Some such as Prasiola crispa can
tolerate high levels of nutrients and are found near bird colonies. Others – the
snow algae - may form extensive and spectacular red, yellow or green patches in
areas of permanent snow. Recent studies have shown that some blue-green algae
live inside rocks in dry valleys. Commonly they are found under stones,
particularly light-coloured quartz stones, where the microclimate is more
favourable than in the surrounding sand or soil. Together with lichens,
they are the only living things in a barren landscape.
Fungi
Fungi have been studied little. Several mushrooms have been found on the west coast
of the Antarctic Peninsula, and on the South Shetland Islands. A few of the fungi
found in Antarctica are unique to the continent. The majority, however, are also
found in most temperate areas>>[/list]