Why oceans are changing colour in to green I Indepth I Drishti IAS?

Oceans are turning green because something new is mixing into their water, like when you add food coloring to a glass of water.

Imagine the ocean as a big, clear bowl of water. Now, think about the land around it, forests, rivers, and soil. When it rains heavily or there's a lot of wind, parts of the land get washed into the ocean, just like when you spill juice on the floor and mop it up.

This wash-in is called runoff, and sometimes this runoff carries algae, tiny green plants that float in water. These algae can multiply quickly, especially if the water gets warm or has lots of nutrients from the land. When there are too many algae, they cover parts of the ocean like a green blanket, changing its color.

If it’s sunny and calm, the green from the algae becomes very clear, like when you look at a green juice through a clear glass. But if it's cloudy or rainy, the water looks more blue again, just like how a muddy puddle can look darker on a rainy day.

So next time you see the ocean turn green, imagine it’s like the sea is drinking a big glass of green juice!