This picture from an electron microscope shows a type of plankton. These plankton give off chemicals that have sulfur in them. The chemicals make tiny particles in the air. Those particles can change Earth's climate!
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Image courtesy of NASA/JPL, photograph by Stefan Gartner.

Sulfate Aerosols from Plankton

Aerosols are tiny particles that float around in the air. Some are tiny drops of liquid. Others are solid. They are all very, very small. Some aerosols come from the ocean. Small particles of sea salt are thrown into the air by the spray from waves. Some microbes that live in the ocean give off chemicals that make aerosols, too.

Some types of plankton give off chemicals that have sulfur in them. These chemicals rise up into the air. They can turn into droplets of sulfuric acid! Chemical reactions in the atmosphere change this acid into various kinds of aerosol particles.

These tiny aerosols actually affect Earth's climate! Some particles reflect and scatter sunlight. Less sunlight makes it to the ground. That makes Earth just a little bit cooler. The aerosols also cause changes in clouds. They make it harder for the clouds to rain. Clouds that "hang onto" their water tend to last longer. Bright, white clouds also reflect sunlight away. That cools down Earth, too.

How can tiny microbes change the climate of a whole, huge planet? Remember that more than two thirds of Earth is covered by oceans. That means there are trillions and trillions of microscopic plankton floating around. Plankton are by far the biggest natural source of aerosols which contain sulfur.

Last modified October 27, 2008 by Jennifer Bergman.

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