Nature Geoscience had a special February 1st, 2012 issue summarized by Scientific American on the same day. Mark Fischetti, writing the summary for Scientific American, noted that the interest of exoplanets that may be similar to earth has led to a surprising theory: we will probably never find a planet similar to earth because of the effect plants have had on this planet’s surface.
We know that oceans and land masses formed, mountains arose and rain washed over the surface of our planet. Rivers weathered rock to make soil and plants took root.
But new research shows that the last part about rocks eroding and plants growing is wrong. Vascular plants (which have xylem and phloem structures which conduct water) created the rivers and muds that built the soils leading to forests and farmland.
The vascular plants began around 450 million years ago to soak up carbon dioxide, more than the oceans were able to. Temperatures dropped, creating widespread glaciation and melting that ground the earth’s surface.
Plants formed the modern rivers we see today, say Martin Gibling of Dalousie University in Nova Scotia and Neil Davies of the University of Ghent in Belgium in another Nature Geoscience article. Water used to run over land in broad sheets with no defined courses. Vegetation to break down rock and hold that mud in place was needed to form river banks. The channeled water led to periodic flooding which deposited sediment over broad areas, building up rich soil that allowed trees to take root. This caused more channels and more flooding, leading ultimately to forests and fertile plains.
Scientific American summarized this process:
"Sedimentary rocks, before plants, contained almost no mud," explains Gibling, a professor of Earth science at Dalhousie. "But after plants developed, the mud content increased dramatically. Muddy landscapes expanded greatly. A new kind of eco-space was created that wasn't there before."
from:
http://www.scientificamerican.com/article.cfm?id=plants-created-earth-landscapel&WT.mc_id=SA_syn_CNET
We know that oceans and land masses formed, mountains arose and rain washed over the surface of our planet. Rivers weathered rock to make soil and plants took root.
But new research shows that the last part about rocks eroding and plants growing is wrong. Vascular plants (which have xylem and phloem structures which conduct water) created the rivers and muds that built the soils leading to forests and farmland.
The vascular plants began around 450 million years ago to soak up carbon dioxide, more than the oceans were able to. Temperatures dropped, creating widespread glaciation and melting that ground the earth’s surface.
Plants formed the modern rivers we see today, say Martin Gibling of Dalousie University in Nova Scotia and Neil Davies of the University of Ghent in Belgium in another Nature Geoscience article. Water used to run over land in broad sheets with no defined courses. Vegetation to break down rock and hold that mud in place was needed to form river banks. The channeled water led to periodic flooding which deposited sediment over broad areas, building up rich soil that allowed trees to take root. This caused more channels and more flooding, leading ultimately to forests and fertile plains.
Scientific American summarized this process:
from:
http://www.scientificamerican.com/article.cfm?id=plants-created-earth-landscapel&WT.mc_id=SA_syn_CNET
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