A very dangerous sea#shorts

If you ever notice the sea going black, don’t swim in it, no matter how tempting it might be. This unusual phenomenon happens when the concentration of specific microscopic algae is higher than normal. Thousands of species of algae in marine and fresh waters are mostly harmless to animals and humans, but some, like the algae that make the sea black, can be extremely dangerous for marine animals, like sea turtles, fish, and sea birds. Find out about some other alarming signs you should stay away from the water.