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What are Phytoplankton?

Phytoplankton are tiny, free-floating marine plants. Phytoplankton produce their own energy by taking in sunlight and converting it into chemical energy. Phytoplankton carry out photosynthesis like land plants, taking in carbon dioxide and releasing oxygen as a byproduct.

Phytoplankton are the foundation of the marine food web.

Phytoplankton absorb carbon dioxide from the atmosphere on a scale equivalent to plants and trees on land, making them a worldwide carbon pump. Any change in phytoplankton growth affects the amount of carbon dioxide in the atmosphere. Studies suggest that there has been a decrease in phytoplankton productivity, which can have a huge impact on biodiversity, food supply and global warming.

 

Global Phytoplankton Decline Over the Past Century

Without phytoplankton, most, perhaps all, of the animals in the food web would die off, and ultimately, our supply of breathable air would be cut in half. A 2010 study in the journal Nature found that populations of phytoplankton have decreased by 40% since 1950. Since 1899, the average global mass of phytoplankton has shrunk by 1%each year.

 

Mathematical Modeling of Phytoplankton—Oxygen Dynamics Under Climate Change

Global warming could affect phytoplankton and the amount of oxygen available in our atmosphere.  If the world’s oceans warmed just 6 degrees, phytoplankton would halt oxygen production. By 2100, the oxygen levels at sea level could be the same as those at the top of Mount Everest.

 

A Reduction in Marine Primary Productivity Driven by Rapid Warming Over the Tropical Indian Ocean

In the past 6 decades, the Indian ocean has seen a reduction of up to 20% of marine phytoplankton. The observations indicate that phytoplankton have decreased up to 30% during the past 16 years. The reduction in marine productivity is attributed to the rapid warming of the Indian Ocean. Changes in plankton production can have immense impact on marine species as well as humans.

Additional Reading: 

What’s happening to the oceans’ phytoplankton?

Failing phytoplankton, failing oxygen: Global warming disaster could suffocate life on planet Earth

Warming Ocean Slows Phytoplankton Growth

Global Warming is Putting the Ocean's Phytoplankton in Danger