Climate change is making our oceans change colour, new research finds
CTV
The colour of the ocean has changed significantly over the last 20 years and human-caused climate change is likely responsible, according to a new study.
The colour of the ocean has changed significantly over the last 20 years and human-caused climate change is likely responsible, according to a new study.
More than 56% of the world’s oceans have changed colour to an extent that cannot be explained by natural variability, said a team of researchers, led by scientists from the National Oceanography Centre in the U.K. and the Massachusetts Institute of Technology in the U.S., in a statement.
Tropical oceans close to the equator in particular have become greener in the past two decades, reflecting changes in their ecosystems, according to the study published Wednesday in the journal Nature.
The colour of the ocean is derived from the materials found in its upper layers. For example, a deep blue sea will have very little life in it, whereas a green colour means there are ecosystems there, based on phytoplankton, plant-like microbes which contain chlorophyll. The phytoplankton form the basis of a food web which supports larger organisms such as krill, fish, seabirds and marine mammals.
It’s not clear exactly how these ecosystems are changing, said study co-author Stephanie Dutkiewicz, senior research scientist in MIT’s Department of Earth, Atmospheric and Planetary Sciences and the Center for Global Change Science. While some areas are likely to have less phytoplankton, others will have more – and it’s likely all parts of the ocean will see changes in the types of phytoplankton present.
Ocean ecosystems are finely balanced and any change in the phytoplankton will send ripples across the food chain. “All changes are causing an imbalance in the natural organization of ecosystems. Such imbalance will only get worse over time if our oceans keep heating,” she told CNN.
It will also affect the ocean’s ability to act as a store of carbon, Dutkiewicz said, as different plankton absorb different amounts of carbon.
