Amargosa Desert, Nevada
High Nitrate in the Desert? What’s Going On?
USGS scientists and their colleagues have unexpectedly found large concentrations of nitrate in desert subsoils. This previously overlooked accumulation of nitrogen is surprising because desert ecosystems are known to have become adapted to a lack of nitrogen. However, the nitrate recently found is within a few meters of land surface and below the biologically active root zone. Contrary to conventional wisdom, small amounts of naturally occurring nitrate appear to have been leaching from soil layers and accumulating for thousands of years in the unsaturated zones of arid regions. Scientists are concerned about this high level (thousands of kilograms per hectare) of nitrate because
Irrigating desert soils, a change to a wetter climate, disposal of liquid wastes, or construction of dams could release large quantities of nitrate to ground water, which in turn could potentially threaten drinking-water supplies (high concentrations of nitrate can cause human health problems).
These accumulations will cause scientists to rethink the long-term movement of nitrate and how nitrate is used (or not used) by plants in desert environments.
Critiques | Translate
Zanni (6108) 2004-10-29 4:18
Sei un pozzo di scienza, Paolo. Certo che hai girato tutto il mondo. Bellissima immagine con tre strisce di differenti colori che ne fanno quasi una composizione astratta.
desman (2220) 2004-10-29 4:33
C'est superbe ! Quel contraste !
gioy (425) 2004-10-29 6:53
A guardarla fa uno strano effetto: mi gira la testa! Non lo so perchè...è come se il mio cervello percepisse al contrario la terra e il cielo. Non so se mi sono spiegata...comunque è proprio bella!
nilolabrador (1469) 2004-10-29 10:46
Questa è un capolavoro. Se non ci fossero i contrail la definirei marziana. Gran colpo!
antymarasek (327) 2005-07-25 4:21
Marlis (2298) 2005-09-07 16:55
very informative notes, thank you.
the sharp colorful foreground and the softer muted tones of the mountains in the background make an interesting contrast to the fuzzy lines of the contrails.
Alfoja (672) 2011-05-07 15:39
A stunning image
unfortunately ruined by those awful chemtrails.