Phytoplankton Population Drops 40 Percent Since 1950

https://www.scientificamerican.com/article/phytoplankton-population/

By Lauren Morello, ClimateWire on July 29, 2010

The microscopic plants that form the foundation of the ocean's food web are declining, reports a study published July 29 in Nature.

The tiny organisms, known as phytoplankton, also gobble up carbon dioxide to produce half the world's oxygen output—equaling that of trees and plants on land.

But their numbers have dwindled since the dawn of the 20th century, with unknown consequences for ocean ecosystems and the planet's carbon cycle.

Researchers at Canada's Dalhousie University say the global population of phytoplankton has fallen about 40 percent since 1950.

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The scientists believe that rising sea surface temperatures are to blame.

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http://earthsky.org/earth/how-much-do-oceans-add-to-worlds-oxygen


By EarthSky in Earth | Science Wire | June 8, 2015

Scientists agree that there’s oxygen from ocean plants in every breath we take. Most of this oxygen comes from tiny ocean plants – called phytoplankton – that live near the water’s surface and drift with the currents. Like all plants, they photosynthesize – that is, they use sunlight and carbon dioxide to make food. A byproduct of photosynthesis is oxygen.

Scientists believe that phytoplankton contribute between 50 to 85 percent of the oxygen in Earth’s atmosphere. They aren’t sure because it’s a tough thing to calculate.

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