Phytoplankton is barely visible to the naked eye. It also lies at the very bottom of the food pyramid. But now its rapid decline could shake the foundations of that very pyramid.
Plankton make up the foundation of the marine food web, while producing half the world's oxygen and sucking up harmful carbon dioxide. That makes them a crucial link for survival of all species. Now, there are signs of their massive decline.
According to a study published in the journal Nature, phytoplankton levels have gone down globally 40 percent since the 1950s. The usual suspect is global warming.
Dalhousie University biology professor Boris Worm who worked on the study says,
"It's concerning because phytoplankton is the basic currency for everything going on in the ocean. It's almost like a recession ... that has been going on for decades."
Historical data shows that plankton levels first started dropping off since 1950s. Except in the Indian Ocean, levels are going down across the world’s oceans with significant declines in the Arctic, southern and equatorial Atlantic and equatorial Pacific oceans. Researchers say that though the signs are "worrisome," it is too early to predict the obliteration of plankton.
But as Virginia Burkett, the chief climate change scientist for the U.S. Geological Survey, says,
"These tiny species are indicating that large-scale changes in the ocean are affecting the primary productivity of the planet.”
Micro-effects of plankton decline can be seen during changes wrought by El Nino climate cycles. Marine birds and marine mammals starve and die in huge numbers.
Lead author Daniel Boyce, from Dalhousie University in Halifax, Nova Scotia says, "Phytoplankton ultimately affects all of us in our daily lives. Much of the oxygen in our atmosphere today was produced by phytoplankton or phytoplankton precursors over the past 2 billion years."
The dangers are probably caused by global warming which is causing the surface temperature of the oceans to rise. Warm water at the top does not mix with the deeper cooler waters. Phytoplankton which thrives on the surface is deprived of nutrients because of this immiscibility of water.
Plankton is microscopic as well as a visible life form. But it is its impact and now lack of it that could determine the future.