Our Bacterial Ancestors

Primordial seas did not part and disgorge a sea-creature destined to shed its fins and gain limbs, instead learning to breathe the ambient oxygen and swing from trees. There were antecedents, needless to say, although few of us can claim to have any real insider knowledge about the process through direct observation.

It would appear that 2.7-billion years ago volcanic lava in our cooling planet invested our already mineral-rich seas with nickel. So, nickel, so what? Inanimate minerals have nothing in common with animate life. But it seems there was a connection, new research from a geomicrobiologist at the University of Alberta has revealed.

Kurt Konhauser and his colleagues have hypothesized that the nickel conveyed into the seas contained in lava from volcanic eruptions indeed had an impact on the life-forms that eventually crawled out of the primordial muck that inevitably gave rise to land creatures.

Rocks, up to 3.8 billion years in age, collected from Canada and Australia divulged information that these scientists analyzed, reaching the conclusion on the evidence that nickel levels in sea waters eventually diminished as the earth cooled, resulting in microbes infesting those ancient seas flourishing on the nickel and producing methane, gave over to other microbes that produced oxygen, leading to multi-cellular life.

The microbes producing methane, named methanogens, consumed nickel; without it they could not survive. How's that for early adaptation? Isn't nature incredible? This was obviously a stop-gap creation of hers. Just practising for the real event, yet to come. With the demise of the methanogens due to a growing paucity of nickel, the oxygen-producing microbes began to thrive, as the dominant species.

They worked like the devil to pump oxygen into the oceans and into the air. "You affect one part of the Earth's system and it has ramifications on another", according to Mr. Konhauser. These findings are enthusing other scientists; marine scientist Mak Saito of the Woods Hole Oceanographic Institution says the findings suggest "a single geological change can starve a major oceanic microbial community and thereby change the trajectory of life on Earth".

Yep, yep. But guess what also happened as the core of the planet cooled and volcanoes ceased their incessant eruptions, and nickel no longer spilled so lavishly into the oceans? Glaciation, that began about 2.3 billion years ago, resulting in 'Snowball Earth'. A large drop in atmospheric levels of methane gas might have cooled the atmosphere to the extent that massive glaciation occurred.

Global warming anyone?