On Tuesday, it was the diving pool at the Maria Lenk Aquatics Centre that turned green. Olympic organisers and FINA, the international organisation for swimmers, had competing explanations as to the reason behind the emerald green water that eventually turned a murky dark green as the day progressed.
At first, it was thought the green water was a harmless prank, then it was decided that the chemical balance of the water was incorrect. But the opinion that seems to have won out is that it’s an algae bloom. While the diving competition went on as scheduled, pictures of the pool with comparison photos were all over social media by Tuesday evening.
Wednesday dawned with the once crystal clear waters of the water polo venue tinted a light green, much to everyone’s astonishment. WTVR.com reports that CNN says that in case you don’t know, swimming venues are supposed to be a ” tranquil shade of azure.”
Rio officials are insistent that the water in both pools has passed all tests and is no danger to the athletes. “Yesterday, in mid-afternoon there was a sudden decrease in the alkalinity of the diving pool first,” Rio 2016 spokesperson Mario Andrada said.
The water polo pool seemed to get progressively worse as the day went on, and by the time of the Australia-Japan match, it was almost murky. Competitors were told that both pools should be back to normal by the end of the day Wednesday, although many athletes are wondering about that.
According to the New Scientist, they think the green water is a combination of factors, including sun, heat and still water. Both pools are outdoors and are heated by the sun’s rays in the already warm weather. There is no wind blowing across the waters to stir them up, either.
The rays of the sun break down the chlorine in the water, and this not only makes the water less safe but allows algae to bloom. Nathaniel Storey, a microbiologist from the University of Reading, explained: “If the pools are not adequately treated then an algal bloom can form.”
“The bright green colour itself is caused by the chlorophyll that algae use to convert sunlight into energy – the same substance that causes plants to be green,” he added.
Storey also suggests that the pools have not been properly maintained, saying, “The best way to stop algae is to prevent it in the first place by maintaining a good pool sanitising regime.”
