The composition of the world’s plankton has changed significantly since before the Industrial Revolution, with zooplankton communities shifting poleward by an average 374 miles as a result of warming ocean temperatures. The findings, published in the journal Nature, show the widespread impact climate change is having on marine ecosystems.
“Marine ecosystems have entered the Anthropocene,” the study’s lead author, Lukas Jonkers, a marine scientist at the University of Bremen in Germany, told Carbon Brief. “The changes that we are seeing are now big enough that we can say that these communities are different than before human influence.”
The scientists used foraminifera — a group of 40 hard-shelled zooplankton species whose distribution is largely controlled by temperature — to study changes in plankton composition before and after the Industrial Revolution. This involved looking at historical records in more than 3,500 ocean sediment cores from across the globe, as well as data from sediment traps from 1978 to 2013.
“Planktonic foraminifera communities have changed considerably since the pre-industrial period, and they have done so in proportion to the magnitude of local temperature change,” Jonkers and his colleagues write in Nature.
Zooplankton is a critical component of the marine food web, and scientists warned that while some species will be able to follow their food source to new waters, many others will not. “Even at 1 degree [Celsius of warming], we already see large changes in planktonic foraminifera, and probably also in other marine biota,” Jonkers told Smithsonian. “That means that all these species have to adapt, and at the moment, we don’t know if they can, or if they can do so fast enough.”