2023-07-12 17:02:30
Environment
Climate change might change the color of the oceans
According to a study published Wednesday in the journal “Nature”, more than half of the oceans have turned from blue to green in some parts of the globe. Plankton might be the cause.
PostedJuly 12, 2023, 7:02 PM
The color of the seas, seen from space, can indeed give an idea of what is happening in the upper layers of water.
ArthurHidden/Freepik
Over the past 20 years, more than half of the oceans have changed color, subtly turning from blue to green in some regions, highlighting the effect of climate change on life in the world’s seas, researchers have found.
According to a study published Wednesday in “Nature”, the change is due to a variation in ecosystems, and in particular plankton, which is the centerpiece of the marine food system and plays a crucial role in the global carbon cycle and in the production of the oxygen we breathe.
“The reason we are interested in color changes is that color reflects the state of the ecosystem,” says lead study author BB Cael of Britain’s National Oceanographic Centre.
Green water means more life
The color of the seas, seen from space, can indeed give an idea of what is happening in the upper layers of water: a deep blue means that there is little life, whereas if the water is greener, there is likely to be more activity, especially from phytoplankton which, like plants, contain a green pigment linked to chlorophyll.
Far from being trivial, the evolution of phytoplankton and its concentration in certain regions, to the detriment of others where it might disappear, might upset the entire marine food chain. Scientists therefore want to develop ways to monitor these changes in ecosystems in order to track climate change and establish protected areas.
Shades too subtle to be seen by the naked eye
The ‘Nature’ study broadened the color spectrum, examining seven ocean color hues monitored by the MODIS-Aqua satellite from 2002 to 2022. These hues are too subtle to be perceived by humans and appear largely blue to the naked eye. Its authors compared observational data to computer models of climate change. They came to the conclusion that the observed changes corresponded closely to what had been predicted by the models.
“I’ve been doing simulations for years that tell me these ocean color changes are going to happen. To see this actually happening is not surprising, but frightening,” said Stephanie Dutkiewicz, co-author of the study and a member of MIT’s Department of Earth, Atmospheric and Planetary Sciences.
While further work is needed to determine the exact implications of the color changes, the study authors believe it is very likely that climate change is the cause. “These modifications are consistent with what we know of the changes produced by human activities on the climate”, according to Stephanie Dutkiewicz.
(AFP)Show comments
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