Reporting on their findings in the open access journal Nature Communications, the researchers said satellites should detect these fluctuations in hue, providing early warning of wide-scale changes to marine ecosystems. The researchers said they have developed a global model that simulates the growth and interaction of different species of phytoplankton, or algae, and how the mix of species in various locations will change as temperatures rise around the world. They also simulated the way phytoplankton absorb and reflect light, and how the color of the ocean varies as global warming affects the makeup of phytoplankton communities.
They predict that by 2100 more than 50 percent of the world’s oceans will shift in color, due to climate change.
Their research suggests that blue regions, such as the subtropics, will become even more blue, reflecting even less phytoplankton and life in general in those waters, compared with the current status. Some regions that are now greener, such as those near the poles, may turn even deeper green, as warmer temperatures brew up large blooms of more diverse phytoplankton.
Lead author Stephanie Dutkiewicz said their model suggests that changes won’t appear huge to the naked eye, and the ocean will still look like it has blue regions in the subtropics and greener regions near the equator and poles, “but it’ll be enough different that it will affect the rest of the food web that phytoplankton supports,” she said. “It could be potentially quite serious,” she added. “Different types of phytoplankton absorb light differently, and if climate change shifts one community of phytoplankton to another, that will also change the types of food webs they can support.”
The study was also reported at EurakAlert, the online journal of the American Association for the Advancement of Science.