The Amazon River nurtures a bounty of life -- the creatures that inhabit its waters, and the world’s largest rain forest around it. It also nurtures life when it empties into the Atlantic Ocean -- a bounty of microscopic plants that may play a role in regulating Earth’s climate.
Symbiotic organisms glowing orange inside phytoplankton. Credit: Tracy VilllarealThe plants are known as phytoplankton, and they’re found in the top layers of all the world’s oceans. In recent years, scientists have been studying the role they play in regulating Earth’s climate.
Scientists know that phytoplankton incorporate carbon dioxide from the atmosphere into their own bodies. When they die, they sink deeper into the ocean, where they can lock up the carbon for a long time. Reducing the amount of carbon dioxide in the atmosphere helps reduce global warming.
But there are questions about how much carbon the phytoplankton can remove from the air -- and what happens to both the phytoplankton and the oceans as a result.
A recent study found that every year, there’s a massive “bloom” of phytoplankton well out in the Atlantic from the mouth of the Amazon. The bloom is fed in part by symbiotic organisms living inside the plankton. They use nitrogen in the air as a nutrient, allowing the phytoplankton to flourish. The phytoplankton can then soak up more than 20 million tons of carbon dioxide a year.
Many of the phytoplankton are of a variety that make shells. They’re fairly heavy, so when they die, they may sink deep into the Atlantic, locking away their carbon for many years.
