The change in the coloration and presence of phytoplankton will cause the characteristic colors with which we see the ocean change from here to the end of the century because of the threat of global warming.
By the end of this century, the world’s oceans will be bluer and greener due to a warmer global climate, according to a study published yesterday. Although the change of tonality will be practically imperceptible to the human eye, it is one more indicator of the profound changes that are expected for the totality of marine life due to climate change.
At the heart of the phenomenon are tiny marine microorganisms known under the name of phytoplankton, essential to supply submarine feeding networks and complete the global carbon cycle. These are extremely sensitive to the temperature of ocean waters. Because of the way in which light is reflected in organisms, phytoplankton blooms are responsible for creating colorful patterns on the surface of the ocean, even though the water is transparent.
Climate change will fuel the flowering of some phytoplankton in some areas, while reducing it in other places, which will lead to subtle changes in the appearance of the ocean, whose color seems deep blue when there is little phytoplankton present and green when more phytoplankton is present in water. According to NASA, when sunlight hits the ocean, some of the light is reflected directly, but most of it penetrates the surface of the ocean and interacts with the water molecules it encounters. By looking closely at the colors of the ocean, scientists can better understand phytoplankton and analyze the impact on their changes.
“Color will be one of the first signs,” said Stephanie Dutkiewicz, a senior research scientist at MIT’s Center for Global Change Science and co-author of the study published in Nature Communications. The author emphasizes that thanks to analysis, although it is not visible to the naked eye, it has already been proven that the color of the sea has changed, since phytoplankton, fundamental for burying carbon in the deep sea, is vulnerable to the warming of the oceans.
According to NASA, global warming modifies the key properties of the ocean and can affect the growth of phytoplankton, which does not only need sunlight and carbon dioxide to thrive, but also a certain series of nutrients. “As the surface water heats up, the water column stratifies more and more; there is less vertical mixing to recycle nutrients from deep water to the surface. “
Dutkiewicz said that several scientific models suggest that there is likely to be a decrease in the total amount of phytoplankton in the oceans over time. The climatic model constructed by his team projects changes in the oceans throughout the present century, including its optical properties.
The world has already warmed more than 1.8 degrees Fahrenheit since the nineteenth century, and at the current rate, scientists predict that warming could accelerate in the coming decades if nations do not take serious measures to reduce carbon dioxide emissions. The panel of scientists supported by the United Nations said last year that it will require an “unprecedented” action in the next decade so that the world avoids the most catastrophic consequences of climate change, whose irreversible limit they have placed in 2030.
Meanwhile, a complex network of satellites that monitors the luminosity that comes from the Earth’s surface will provide early signals of how climate change is altering the oceans and their color. If certain types of phytoplankton, the base of the food chain and extremely diverse, disappear, the fish and organisms that can survive will change, completely altering ecosystems and the carbon cycle.