How Our Oceans Are Changing Colour!

We should all know by now the effects that climate change is having on our earth; temperatures rising, sea level rising, extreme weather events becoming more frequent. These are the issues most closely associated with climate change, but each of these consequences creates multiple other issues for our Earth.

A recent paper published in Nature Communications found that with a business as usual model, our oceans will change colour by 2100. It’s not what you’re thinking, we won’t suddenly be swimming in a purple or grey ocean, it’s just that the colour will become more vibrant. The beautiful blues you see around the equator, and greens you see around the polar regions will become more vibrant in their colours, however, not to the naked eye.

With warming temperatures, there will be increased stratification of water layers, and less mixing between hot and cold regions. The meridian circulation will also slow due to this decrease in mixing, causing less nutrients to be supplied from deeper, colder waters.

This alone won’t cause colour change, however, what it will affect is the populations and abundance of phytoplankton. Some species will adapt to this change by moving with the temperature, but others might not be able to. This is important because phytoplankton absorb the sunlight for nutrients, and they are the basis of the food chain. In nutrient poor blue parts of the ocean, there are less phytoplankton present, and therefore less Chlorophyll being absorbed, resulting in the blue colour due to the greater amount of blue light being absorbed. The opposite occurs in the greener, polar parts of the ocean. Therefore, if temperatures rise, some phytoplankton might not be able to cope, becoming extinct or moving further south, creating greener waters at the pole, and bluer waters near the equator!

But obviously, as phytoplankton are the basis of the food chain, if their numbers decrease, we will lose those animals who cannot adapt. As pretty as the waters might look, I’d rather an abundant ocean than instagrammable pictures!

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