Around 500 million years ago life in the oceans rapidly diversified. In the blink of an eye -- at least in geological terms -- life transformed from simple, soft-bodied creatures to complex multicellular organisms with shells and skeletons. Now, research has shown that the diversification of life at this time also led to a drastic change in the chemistry of Earth's crust -- the uppermost layer we walk on and, crucially, the layer which provides many of the nutrients essential to life.