Why do the oceans change color and what does it mean for the future of the planet

he The color of the ocean has changed dramatically in the past 20 years Scientists believe such a change can be attributed to climate change caused by human activity, according to a study published Wednesday in the Scientific Journal. nature.

Research by the Massachusetts Institute of Technology (MIT) and the National Oceanography Center in the United Kingdom states that “more than 56% of the world’s oceans have changed color to a point that cannot be explained by natural variability.

According to the study, tropical oceans near the equator in particular have become greener in the past two decades, reflect changes in their ecosystems.

The researchers explain that the color of the ocean is a visual product of whatever is in its upper layers, and point out that the deep blue waters reflect very little life, while the greener waters indicate the presence of ecosystems, primarily phytoplankton. Plant-like microbes are abundant in the pelagic ocean that contain the green pigment chlorophyll.

said study co-author Stephanie Dutkiewicz, senior investigator in MIT’s Division of Planetary, Atmospheric, and Earth Sciences and the Center for Global Change Science.

Dutkiewicz said she wasn’t surprised by the change in ocean color, but terrified, as it indicated A disruption in the fragile food chain that will only get worse as climate change accelerates.

Another cause for concern is the ability of marine waters to capture and store carbon dioxide because phytoplankton are also a powerful tool in this task and “different types of plankton have different abilities to do this,” Dutkiewicz explains.

Researchers are still working to find out exactly what these changes mean, but what they have no doubt about is that the changes are being driven by human-caused climate change.

The researchers have been monitoring changes in ocean color from space, by measuring the amount of green or blue light reflected off the sea surface.

They used data from the Modis-Aqua satellite, launched by NASA in 2002, which is able to detect differences invisible to the human eye.

The color variations that occurred between 2002 and 2022 were fed into the climate change model to try to simulate changes that would occur in the oceans in two scenarios: with or without additional pollution further warming the planet.

The results in the higher pollution scenario were almost entirely in line with the model and Dutkiewicz’s predictions, as well as with the changes that occurred. While Dutkiewicz said about 50% of our oceans will change color, Reality shows a change of about 56%.

The next step for the scientific community is to try to better understand what these color changes in different regions of the ocean represent and what could be causing them.