As the Olympic Summer Games 2016 continue, we’ve seen some exciting finishes and more gold medals for aquatic phenom Michael Phelps and the rest of the amazing US swimming team. We’ve also seen a strange, but natural occurrence: an Olympic diving pool turned green! The green color was caused by a proliferation of tiny but harmless algae. But that green hue got us thinking: What else is there besides your basic blue for a pool?
Leonardo DaVinci said “Water is the driving force in nature.” Because our bodies are mostly water, it’s in our nature to live near bodies of water. Most of the Earth’s population lives within a few kilometers of a lake, river or sea. According to the US National Oceanic and Atmospheric Administration, 39% (123.3 million people) of Americans lived in counties that contained one of the country’s shorelines, which is 6x more people than live in the corresponding counties more inland. The US National Institutes of Health noted in a 2011 study that only 10% of humans live more than 10km away from a freshwater source.