Producing half of the oxygen in the atmosphere, phytoplankton are one of Earth’s 2 lungs. Land plants are the other planetary lung.
Plankton live near the ocean’s surface. They are sensitive to environmental changes and are seriously stressed throughout much of the world.
Plankton cannot swim, but they can somewhat position themselves in response to turbulence cues. When conditions become unfavorable, plankton have 3 options: adapt, hitch a ride on ocean currents to a more hospitable place, or die out. All 3 processes are in overdrive.
Smaller plankton have been able to withstand their environment becoming more inhospitable. But larger species – major players in oxygen generation and as fish food – cannot cope. Unable to take the warmth and greater acidity, many critical phytoplankton in the North Atlantic have been declining for decades.
Meanwhile, billions of plankton are on the move: surfing the waves for a better habitat. They are heading poleward, to cooler waters. Several key species have been traveling at 99 kilometers per decade, aiming for a better life for their offspring.
Other plankton are simply dying out, including ones that fisheries crucially depend upon. From 1950 to 2010, the planet’s phytoplankton population dropped 40%. The outcome has been over a 2% drop in oceanic oxygen levels; a trend that shows no sign of reversing.
As the base of the oceans’ food web, plankton decline has also irredeemably reduced the seas’ baseline fecundity; an effect partly masked by overfishing.
Phytoplankton is the fuel on which marine ecosystems run. A decline of phytoplankton affects everything up the food chain, including humans. ~ Canadian marine biologist Daniel Boyce