Black Sea is black?

The Black Sea is really not black. The satellite image of the US Aeronautics and Space Agency (NASA) shows bright colors intertwined between cyan, turquoise and blue. These swirling patterns on this surface are caused by planktonic planktons called coccolithophore.

Dead Sea taken from satellites

According to New Scientist, these single-celled microorganisms attract carbon from the air, combining them with calcium and oxygen to form small membranes of calcium carbonate called coccolith. When they die, they sink to the bottom of the ocean and are eventually eaten and excreted by other sea creatures.

In this way, the coccolithophore will act as the 'biological pump' of the ocean. This is also part of the carbon cycle that transfers carbon from the air to many depths of the ocean. Marine microorganisms such as coccolithophore can accelerate this process, reduce the amount of CO ₂ in the atmosphere when they are calcified and sink into the sediment.

However, the increased content of CO2 in the air can cause trouble for this 'pump'. When more CO ₂ enters the sea, it increases the acidity of the seawater. This changing water condition may affect coccolithophore's ability to grow and calcify.