Microbes Evolved to Form Nitrogen Billions of Years Ago
19 February 2009
The nitrogen cycle that occurs on earth has many different facets. Nitrogen in the atmosphere (N2) is converted into nitrates (NO2 and NO3) by bacteria through a process of nitrification. These nitrates are then converted back into Nitrogen (N2) by bacteria through the process of denitrification. Researchers have discovered some trace of denitrification in a core sample. They take the logical leap to say this is proof that the nitrogen cycle was occurring at the time that layer was near the surface; however, they then take an illogical leap.
Good Science
"Scientists examined material from a half-mile-deep core drilled in the Pilbara region of northwest Australia. They looked specifically at a section of shale from 300 to 650 feet deep, deposited 2.5 billion years ago, and found telltale isotope signatures created in the process of denitrification, the removal of oxygen from nitrate."
Good Science = Good Conclusion
"If denitrification was occurring, then nitrification -- the addition of oxygen to ammonia to form nitrate -- also must have been taking place, Buick said. That makes the find the earliest solid evidence for the beginning of the aerobic nitrogen cycle."
Good Science = Bad Conclusion
"But the new research shows that about 2.5 billion years ago some microbes evolved that could carry the process a step further..."
Please select the answer that can scientifically be known from observing denitrification in a rock layer:
A. There was no nitrogen anywhere on earth until the day this layer formed.
B. At first there was nothing, then small incredibly complex creatures evolved to create nitrogen.
C. Denitrification was occurring in this layer.
D. Aliens came and put nitrogen there.
The correct answer? C
All you can empirically tell from marks on a layer of rock is that there are marks on a layer of rock. You then have to make the leap of faith that the incredibly complex bacteria that caused these marks evolved out of noting. At this point you leave the realm of empirical science and enter the liberal art of speculation.
http://uwnews.org/article.asp?articleID=47460
