Ancient Worms May Have Saved Life On Earth 54
sciencehabit writes You can credit your existence to tiny wormlike creatures that lived 500 million years ago, a new study suggests. By tunneling through the sea floor, scientists say, these creatures kept oxygen concentrations at just the right level to allow animals and other complex life to evolve. The finding may help answer an enduring mystery of Earth's past. The idea is that as they dug and wiggled, these early multicellular creatures—some were likely worms as long as 40 cm—exposed new layers of seafloor sediment to the ocean's water. Each new batch of sediment that settles onto the sea floor contains bacteria; as those bacteria were exposed to the oxygen in the water, they began storing a chemical called phosphate in their cells. So as the creatures churned up more sediment layers, more phosphate built up in ocean sediments and less was found in seawater. Because algae and other photosynthetic ocean life require phosphate to grow, removing phosphate from seawater reduced their growth. Less photosynthesis, in turn, meant less oxygen released into the ocean. In this way, the system formed a negative feedback loop that automatically slowed the rise in oxygen levels as the levels increased.
Re:Saved the earth (Score:4, Interesting)
The worm theory is not new, this appears to be more evidence to support it. A similar process helps regulate CO2 today in the southern ocean, algae grows on or near the surface and sucks up CO2 and release O2, the algae attract large schools of krill that feed on it. The algae give off a particular smell when they are attacked, the smell attracts seabirds (and marine predators) who eat the krill by the ton.
Here's the beautiful part (to a "systems programer"), the birds and whales shit in the water when feeding on krill, the bird shit in particular is rich in phosphorus and iron (from the krill) which fertilises a new generation of algae.