Does the entire surface of the earth contain organisms?

Question

Does the entire surface of the earth contain organisms? My teacher mentioned that in some parts of the earth, there aren't any organism. Is this true?

Thanks in advance.

Answer 1

Barring the very obvious surfaces (the pits of active volcanoes), the only place I'm aware of that might not contain life is the Atacama Desert near the Andes Mountains in Chile and Brazil.

Whereas other places that seem inhospitable - Antarctic, Hot Springs, regular deserts, extremely high altitudes, etc. - the basic necessities for life still exist (carbon, water, nitrogen). In the Atacama, though:

The average rainfall in the Chilean region of Antofagasta is just 1 millimetre (0.04 in) per year. Some weather stations in the Atacama have never received rain. Evidence suggests that the Atacama may not have had any significant rainfall from 1570 to 1971... Studies by a group of British scientists have suggested that some river beds have been dry for 120,000 years.

It's the driest place on the planet. It's drier than every other desert by a long shot, and is so dry that NASA occasionally uses it to simulate Mars.

In 2003, a team of researchers published a report in the journal Science titled "Mars-like Soils in the Atacama Desert, Chile, and the Dry Limit of Microbial Life" in which they duplicated the tests used by the Viking 1 and Viking 2 Mars landers to detect life, and were unable to detect any signs in Atacama Desert soil. The region may be unique on Earth in this regard and is being used by NASA to test instruments for future Mars missions. The team duplicated the Viking tests in Mars-like Earth environments and found that they missed present signs of life in soil samples from Antarctic dry valleys, the Atacama Desert of Chile and Peru, and other locales.

So while life might exist in the Atacama (signs of life do not always point towards currently-existing life), it's hiding extremely well. Probably beneath the topsoil, where no multicellular organisms have ever been spotted and unicellular organisms may not exist at all.

Ultimately your teacher is correct, although whether they meant the Atacama or erroneously considered other places on the planet you'll have to ask them.

Answer 2

That will depend on many things. How do you define surface? Is one meter underground still "surface"? How about a kilometer?

Also, how large an area are we talking about? You could probably find a square millimeter in, for example, Antarctica that has no organisms. I don't think you would find a square kilometer with no organisms though.

There are organisms (called extremophiles) that thrive in the most hostile environments we know, they can survive extreme heat, cold, acidity, salinity etc. I found this very nice list:

• Cold – The McMurdo Dry Valleys in Antarctica are some of the coldest, driest deserts on Earth, with average annual temperatures of -20oC (-4oF) and less than 10 centimeters (4 inches) of precipitation a year. Scientists have found bacteria in liquid water pockets embedded about twelve feet deep in “solid” lake ice. Some of these bacteria use chemical nutrients from particles of dirt in the ice and use energy from sunlight for photosynthesis.

• Hot – Large concentrations of microbes thrive in Yellowstone National Park’s Grand Prismatic Springs, a hot spring with water temperatures up to 90oC (188oF). Other hot springs in Yellowstone are extremely acidic, yet are home to many different kinds of bacteria and microbes. Many of these microbes use chemical nutrients in the waters and energy from sunlight for photosynthesis. Deep underground – Scientists have discovered bacteria living in ground- water 5 kilometers below the surface in deep gold mines of the Witwatersrand Basin in South Africa. These microbes thrive in cavities and cracks in rocks. Scientists are also are investigating life within and below permafrost in north- ern Canada.

• Bottom of the sea – Scientists have found abundant life clustered around hydro- thermal vents on the ocean floor, including bacteria, mussels, clams, shrimp, and giant tubeworms that can reach ten feet in length. Water pouring out of the vents in the complete darkness thousands of feet under the surface of the sea can reach temperatures of 113-120oC (235-248oF). The high pressures keep the water from boiling. Bacteria use chemicals in the vent’s water, primarily hydrogen sulfide, as their energy source instead of sunlight. Other creatures survive by eating the bacte- ria or each other.

• High Acidity – The water in the Rio Tinto in southwestern Spain is very acidic, a result of chemical reactions between the water, and iron and sulfur minerals in the ground. The river has a deep red color, like wine, because of iron dissolved in the water. Microbes living in the water use chemical reac- tions with iron and sulfur minerals to generate the energy they need. Products from these metabolic reactions contribute to the low pH in the environment. Many algae and fungi also live in the acidic waters.

As far as I know, there is no evidence of life in molten lava. Apart from that though, just about every habitat you can find on the earth has been colonized by life. Ask your teacher what parts of the earth she is talking about, and report back here.

UPDATE:

MCM's very interesting answer prompted me to do some more research. It seems that life has now been found even in the Atacama (taken from Azua-Bustos et al):

For a long time it was thought that regions of the Atacama could not uphold any type of life forms. However, recent culture-independent methods (metagenomics, transcriptomics, in situ hybridization, etc.) have improved the sensitivity for life detection. Thus, microorganisms have been found even in the driest areas of this desert, which makes scientists wonder about the true limit of water availability needed to sustain life as we know it. In this review, we summarize the efforts devoted to the characterization of microbial life in the Atacama Desert.

So, it seems that life can exist even in the Atacama. That leaves only molten lava...

Reference

Azua-Bustos et al, Life at the dry edge: microorganisms of the Atacama Desert, FEBS Lett. 2012 Aug 31;586(18):2939-45

Answer 3

Sterile! Lake Vostok’s microbes elusive in first measurements of surface water

A first analysis of the ice that froze onto the drillbit used in last February’s landmark drilling to a pristine Antarctic lake shows no native microbes came up with the lake water, according to Sergey Bulat of Petersburg Nuclear Physics Institute (Russia). The very uppermost layer of Lake Vostok appears to be “lifeless” so far, says Bulat, but that doesn’t mean the rest of it is. Bulat reported what he calls his team’s “very preliminary results” on Tuesday, at the 12th European Workshop on Astrobiology (ENEA 2012), in Stockholm, Sweden, at the AlbaNova University Center. Bulat and his colleagues counted the microbes present in the ice sample and checked their genetic makeup to figure out the phylotypes. They counted fewer than 10 microbes/ml — about the same magnitude they would expect to find in the background in their clean room. And three of the four phylotypes they identified matched contaminants from the drilling oil, with the fourth unknown but also most likely from the lubricant. Bulat hopes to get clean samples from the ice frozen in the borehole below where the drill bit stopped. That won’t be until next May (2013), if all goes well after the next Russian drilling expedition in December-January. Even if the top of the lake ends up being empty, Bulat suspects microbes will come from lower water depths, or from sediment samples at the bottom of the lake. Lake Vostok is a stand-in for icy bodies that might harbor life, like Jupiter’s moon Europa. Gerda Horneck of the German Aerospace Center (DLR) said that any result from Lake Vostok is important for astrobiology, and the search for extremophiles that could give hints of what life could be like elsewhere. “Let’s see what comes out next round,” she told me at the end of the meeting on Wednesday.

http://www.scoop.it/t/amazing-science/p/3031509753/sterile-lake-vostok-s-microbes-elusive-in-first-measurements-of-surface-water

More info on Lake Vostok:

http://earthsci.org/education/Lake_Vostok/vostok.html