3 January

The drama around blue-green algae and recreational dam use. What’s less known is that it’s the greatest killer in the history of planet Earth. It’s not really an algae, it’s a bacteria, cyanobacteria. And it’s the origin of the atmosphere as we know it today, it produced then (and still does now) most of the oxygen in the atmosphere. About 2.5 billion years go it started what’s called the Great Oxygenation Event. That’s when the vast amounts of oxygen it produced bubbled out of the oceans and formed the atmosphere we know today. In the process of doing that, it killed 90% of all life on Earth. The earliest life on Earth was mostly anaerobic, and oxygen killed it. Still the greatest mass murder in history, and some scientists even question whether it was a key player in the other 5 mass extinction events in history. So it’s a real tricky beast, because without it we couldn’t breathe. But it can kill most things that swallow it, including us. And oxygen is vital for our life, but also a poison for living things in other ways. Oxidation is a toxic process. It’s also been linked to motor neurone disease. Let’s just say - you don’t want to be swimming in it.