Olympic authorities were quick to deny that the green pool posed a risk to divers’ health, but that actually depends on why the water changed colour.
The possible culprits are: a sudden algae bloom; a change in pool alkalinity; or a chemical reaction in the water. How do these cause a change in the colour of the water?
Pretty, but also pretty nasty.
Willem van Aken/CSIRO/Wikimedia Commons
With El Niño ramping up, Australia is in for a long, hot, dry summer - perfect conditions for blue-green algae. And that innocuous-looking pond scum can pack a toxic punch if you're not careful.
The Swedish Byfjord: it may look healthy, but has a deep and stifling secret.
Low oxygen levels in the oceans can dramatically change the community of organisms that live there -- but new techniques to re-introduce oxygen have given a breath of life to a Swedish fjord.
Chemicals are all around us. They are crucial in all manner of industries, from agriculture to food to cosmetics. Most people give little thought to how these chemicals are made – and certainly very few…