Scientists believe that climate change is causing the oceans to change color

Over the past two decades, more than half of the world's oceans have experienced a change in color, shifting from blue to green in some areas. This phenomenon highlights the impact of climate change on marine life worldwide, according to researchers in a study published in the journal "Nature" on Wednesday.

The study indicates that the change in ocean color is attributed to variations in ecosystem dynamics, particularly in the phytoplankton, which are key components of the marine food system. They play a crucial role in the global carbon cycle and the production of oxygen that humans breathe.

Speaking to AFP, the lead author of the study, Dr. Beeb Kuylen, from the National Oceanography Centre in the UK, stated, "We are interested in the changing color of the oceans because color reflects the state of the ecosystem."

The color of the seas, visible from above, can provide an idea of what is happening in the upper layers of the water. Dark blue indicates limited activity, while a shift towards green suggests increased activity, particularly in plant-like phytoplankton, which have a green pigment associated with chlorophyll.

The proliferation and presence of phytoplankton in large quantities in certain areas, at the expense of disappearing from other areas, can radically alter the entire marine food chain.

Scientists are therefore keen to adopt methods to monitor these changes in ecosystems in order to track climate variations and establish protected areas.

The study expanded the range of colors examined, examining seven ocean colors observed by the "MODIS-Aqua" satellite between 2002 and 2022. These colors are so subtle that humans cannot distinguish between them, perceiving them as simply blue.

The researchers compared monitoring data with climate change modeling and found that the changes in color closely align with what the models predicted.

One of the study's co-authors, Stephanie Dutkiewicz, said, "I have been doing simulations for years that showed that changes in the color of the oceans would occur." She added, "Seeing that actually recorded is not surprising, but it is alarming."

Although further research is needed to determine the precise effects of changes in ocean color, the study's authors point to climate change as a possible cause.

Dutkiewicz emphasized that "these changes are consistent with what is known about the changes caused by human-induced climate activities."

 

AFP