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EarthSky // Today's Image Release Date: Sep 03, 2013

Plankton bloom on Lake Ontario

All the Great Lakes have suffered these harmful algal blooms. Drought, invasive species, runoff and sewage, and warmer-than-average temps all contribute.

View larger. | This photograph taken by an astronaut on the International Space Station highlights a late summer plankton bloom across much of Lake Ontario, one of North America’s Great Lakes. Microscopic cyanobacteria, or blue-green algae, can reach such large concentrations and color the water to such an extent that the change is visible from orbit.

View larger. | Late summer plankton bloom across Lake Ontario on August 24, 2013.

An astronaut on the International Space Station captured this image of a late summer plankton bloom across much of Lake Ontario, on the U.S. Great Lakes, on August 24, 2013. The greenish color is due to microscopic cyanobacteria, or blue-green algae, which can become so dense in the water, and color it so vividly, that the change is visible from orbit. NASA said:

Harmful algal blooms, or HABs, have been observed in all of the Great Lakes — particularly Lake Erie — and are caused by a variety of factors, including: changes in precipitation; drought; invasive species (quagga, zebra mussels, Asian carp); nutrient loading from runoff and sewage (nitrogen and phosphorus); and warmer-than-average temperatures …

Astronaut photograph ISS036-E-35635 was acquired on August 24, 2013, with a Nikon D3S digital camera using a 50 millimeter lens, and is provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Center. The image was taken by the Expedition 36 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed.

Read more from NASA’s Earth Observatory.

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