Lichens are colonies of tiny plants, and they live on rocks. I heard that conservators have to remove them from Mount Rushmore, but what do they do to the monument?
2006-07-28 20:47:06 · 5 answers · asked by ttogreh 2 in Science & Mathematics ➔ Earth Sciences & Geology
They hasten the erosion of the granite from which the monument is carved. Gravity by itself, along with wind, rain, ice melt and thaw, pressure release on the surface of the rock, etc. all contribute to minute pieces of the carvings to fall.
As such, there is no way to stop the erosion/decay completely, so the conservators do every little thing within their powers to slow it. Keeping lichens from growing on the surface is just one of those things.
In addition to the "decay" of the rock caused by the action and growth of the lichen itself, it serves as a place for water to collect which creates one more place for freezing and thawing cycle to speed the breakup of the rock.
Since it can retain moisture, it can also serve as a "home" for other small creatures which in turn leads to further erosion. For example, a seed may land there (wind blown, dropped by a bird or passing animal) and begin to grow. Even if it never grows more than an inch or so, by putting out roots it helps break the rock even more. That's just one example. I am sure you could think of similar processes.
2006-07-29 03:33:32 · answer #1 · answered by idiot detector 6 · 3⤊ 1⤋
Lichens aren't quite colonies of tiny plants. They are a symbiotic relationship between an alga and a fungus. Where else in the world do two species combine to form another? Anyway, they are early colonisers of bare rock, soil and wood (as well as glass and some metals). They don't have a root system as such, as they get food and water from the air, through their body. They do however create acids that will crack and crumble some rock surfaces. In nature, this is great as it adds rock granules to the soil, and other plant seeds can establish and grow on the mats of lichen. On Mt Rushmore, they might not be so popular.
2006-07-29 06:34:02 · answer #2 · answered by Beck 1 · 0⤊ 0⤋
Lichens are actually a symbiotic relationship between two organisms - either green algae or cyanobacteria and filamentous fungi. Tere are countless different types, but essentially to answer your question - some of them eat rock. However the do so very slowly. A patch of lichen the size of your hand may have take centuries to grow.
2006-07-29 06:37:33 · answer #3 · answered by Kobie 2 · 0⤊ 0⤋
They can decay rock, thus mt rushmore's different faces might start collapsing.
2006-07-29 06:08:06 · answer #4 · answered by Philbert 3 · 0⤊ 0⤋
No clue... are they picnicking? Maybe they forgot to pick up the trash....
2006-07-29 03:55:52 · answer #5 · answered by skypiercer 4 · 0⤊ 0⤋