Climate Change: The Shocking Truth Behind the Ocean Colour Change of 30%
Human-induced climate change is causing a shift in the balance of phytoplankton populations in the sea, which is altering the oceans in profound ways.
The ocean’s colour is a result of what lies within its upper layers, and typically, the phytoplankton ecosystem determines the water’s colour.
Waters that are deep blue contain less life, while greener waters signal the presence of more phytoplankton.
In 2023, research showed huge concentrations of chlorophyll in warming waters around Europe, causing greener waters due to blooms of microscopic plant life rich in chlorophyll.
By studying the wavelengths of sunlight reflected off the ocean’s surface, scientists can estimate how much chlorophyll is present.
Modis, an instrument on Nasa’s Aqua satellite, takes measurements in seven visible wavelengths, which is a fuller colour spectrum than was captured in previous studies based on computer models.
Dr. Cael, a scientist from the University of California, created a model to run simulations using the data from Modis.
This experiment discovered that the colours in 56% of the world’s oceans had changed, with tropical ocean regions near the Equator becoming steadily greener over time, because of the added chlorophyll from increasing phytoplankton.
“We’re seeing changes in all the major ocean basins – it’s not confined to just the Pacific or Atlantic or Indian oceans. These are really global scale changes that we’re seeing,” says Dr. Cael.
This confirms a theory in an earlier paper from Stephanie Dutkiewicz, an oceans scientist in MIT and the Center for Global Change Science.
The greener waters are caused by blooms of microscopic plant life rich in chlorophyll. Different phytoplankton have different combinations of pigments used to photosynthesise, and these pigments absorb light at different wavelengths.
Phytoplankton scatter light because they are particles in the water. By scattering light, they alter the colour of the ocean’s waters.
The study used data from Modis, which takes measurements in seven visible wavelengths, providing a fuller colour spectrum than was captured in previous studies.
Dr. Cael created a model to run simulations using this data, which showed that the colours in 56% of the world’s oceans had changed.
Tropical ocean regions near the Equator have become steadily greener over time, because of the added chlorophyll from increasing phytoplankton.
The study confirms that these changes are not confined to just one ocean basin but are global scale changes.
The greener waters are caused by blooms of microscopic plant life rich in chlorophyll, and different phytoplankton have different combinations of pigments used to photosynthesise, which absorb light at different wavelengths. By scattering light, they alter the colour of the ocean’s waters.
The research highlights the profound ways in which human-induced climate change is altering the oceans.
The study’s findings are significant because they provide evidence that the oceans are changing in ways that were not previously understood.
Understanding how the oceans are changing is crucial for predicting the effects of climate change on marine ecosystems and the global environment.
