January 28, 2021

Much of the surface of the ocean will change color by the end of the 21st century

Much of the surface of the ocean will change color by the end of the 21st century

There is a place in Lanzarote where the water takes on an olive green color. He is intense and contracts a lot with the black sand that surrounds him. It is the Laguna de los Clicos and is embedded in the middle of two mountains, which further intensifies the tone of its waters. This is due to the high concentrations of sulfur that exist in the ground. Something similar to what happens in Las Coloradas, a small port in Yucatán. There, the concentration of salt and microorganisms make their waters are dyed a peculiar pink. The cambio climatic is causing important changes in phytoplankton and that, in the coming decades, will make the color of the oceans become as characteristic as in these first two places.

They will be bluer and greener. They will shine brightly and the alerts will jump. According to the study by the Massachusetts Institute of Technology (MIT), these organisms will mix with many others as the global temperature increases throughout the world. To prove this, researchers have developed a model that simulates the growth and interaction of different species of phytoplankton and algae, as well as reproducing the way in which light is absorbed and reflected. The main conclusion is that the color of the water changes as global warming affects these communities and that, therefore, by 2010, more than 50% of the world's oceans will transform tonality as a consequence of climate change.

The analysis, published in the journal Nature Communications, suggests that blue regions, such as subtropics, will become even brighter; like that of the poles, in which the green will become more intense. "The changes will not seem so extreme to the naked eye," says lead author and head of the Department of Earth Sciences at MIT, Stephanie Dutkiewicz. "Even so, it will be different enough to affect the food web of phytoplankton." The final color will depend on how the sunlight interacts with all the elements that are in the water. If there are organisms in it, they can absorb and reflect different wavelengths.

Since the end of the 90s, satellites have determined these variations thanks to the amount of pigments, such as chlorophyll, present in the sea. Although Dutkiewicz assures that this data does not necessarily reflect the effects of climate change: any of its alterations could also be due to "natural variations". Therefore, instead of looking for evidence from chlorophyll, they chose to control the variations of light through the satellites. "It is a complicated process to understand how light is reflected in the ocean to give it its color." When the group compared the results with the measurements made by the satellites in the past, they found that they matched and served to predict the evolution of the color of the oceans.

In response to its prediction, climate change is changing the composition of phytoplankton and, by extension, the color of the oceans. At the end of the century, our blue planet could be especially altered. "There will be a noticeable difference in the color of half of the oceans by the end of the 21st century," concludes the researcher. "That could be potentially serious. Phytoplankton always absorbs light differently, so if climate change alters its composition, it could also change the way you feed. " Even, the way it reflects light.


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