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Lack of Molybdenum May Have Delayed Life on Earth
esocid writes "Scientists from around the world have reconstructed changes in Earth's ancient ocean chemistry during a broad sweep of geological time, from about 2.5 to 0.5 billion years ago. They have discovered that a deficiency of oxygen and the heavy metal molybdenum in the ancient deep ocean may have delayed the evolution of animal life on Earth for nearly 2 billion years. Bacteria cannot fix nitrogen efficiently when they are deprived of molybdenum. And if bacteria can't fix nitrogen fast enough, then eukaryotes — a kind of organism that includes plants, pachyderms and people — are in trouble because eukaryotes cannot fix nitrogen themselves at all. Ariel Anbar, a co-author of the research of Arizona State University, stated that "eukaryotes depend on bacteria having an easy enough time fixing nitrogen that there's enough to go around. So if bacteria were struggling to get enough molybdenum, there probably wouldn't have been enough fixed nitrogen for eukaryotes to flourish.""
This casts an interesting light on the idea of terraforming. There's often been the idea that we could just introduce plants into a CO2 rich environment and in pretty short order we'd have a breathable atmosphere. Apparently that may not be the case. Without an oxygen rich environment to free the molybdenum, there's no significant nitrogen fixation and thus those plants are going to be hurting pretty quickly.
Also, this makes me wonder what those eukaryotes were doing for the first 2 billion years. Were they undergoing all sorts of genetic mutations that primed them for takeover once the situation changed? IOW, I wonder what would have happened if this little molybdenum problem had resolved earlier. Would the eukaryotes continued to flounder (pun!) because of a lack of genetic diversity? Or would they have just as rapidly developed putting the current day well into the cockroaches-rule-the-earth epoch?
man, I feel like mold.
According to wikipedia.
Coincidence? I think not!
Bacteria cannot fix nitrogen efficiently when they are deprived of molybdenum So when God created the earth, all of his nitrogen was broken?
I'm an American. I love this country and the freedoms that we used to have.
That reminds me of a quote from Chuck Palahniuk:
.... Does this remind you of anything? Maybe the ol' Adam and Eve story? .... You ever wonder when God's coming back with a lot of barbecue sauce?"
"Centuries ago, sailors on long voyages used to leave a pair of pigs on every deserted island. Or they'd leave a pair of goats. Either way, on any future visit, the island would be a source of meat. These islands, they were pristine. These were home to breeds of birds with no natural predators. Breeds of birds that lived nowhere else on earth. The plants there, without enemies they evolved without thorns or poisons. Without predators and enemies, these islands, they were paradise. The sailors, the next time they visited these islands, the only things still there would be herds of goats or pigs.
Damn near killed 'um!!
*ducks*
Ed R.Zahurak
You know, oblivion keeps looking better every day.
It's so sad when bad things happen to good ideas. The fact that there may have been dearth of molybdenum in the early oceans isn't a crippling blow to the development of eukaryotes.
Nitrogenase, the enzyme that performs nitrogen fixation today, commonly uses, but doesn't require, molybdenum for its function. There are forms of the enzyme that use vanadium or iron as a cofactor to the ubiquitous iron-sulfur cluster that actually performs the chemistry.
I don't know if this event happened before or after the iron catastrophe, but the fact that the enzyme uses iron anyway makes me believe that there must have been enough iron around the oceans back then. Methinks the author's running off the old idea that the nitrogen reduction occurs on the molybdenum atom instead of one of the iron atoms in the iron-sulfur cluster.