NASA MODIS Image of the Day: November 27, 2011 – Phytoplankton bloom off Argentina
On November 14, 2011, a spectacular phytoplankton bloom off Argentina was in full glory, filling the ocean with brilliant green and blue swirls that stretched for hundreds of kilometers.
The Moderate Resolution Imaging Spectrometer (MODIS) aboard NASA’s Terra satellite captured this true-color image at 13:30 UTC on the same day.
The bloom, which started weeks ago, appeared as the MODIS Image of the Day on November 14 with an image captured on November 5. Large and beautiful at that time, it has extended in both length and width, and has now reached massive proportions. Phytoplankton requires sunlight and favorable water temperatures for growth. But they also require nutrients. The nutrients spurring the abundant growth in the ocean off of Argentina may have originated in part by volcanoes in the mountains of Chile. Three volcanoes – Cerro Hudson, Chaiten and Puyehue-Cordon Caulle – have been pouring volcanic ash into the air in the past several months. Puyehue-Cordon Caulle has been especially active, with ash extending over Argentina and far out to sea. Volcanic ash is rich in iron – and iron is one nutrient that spurs phytoplankton into luxuriant growth. When iron levels in the ocean are low, the lack of this nutrient limits growth and phytoplankton remain sparse. When iron levels rise – such as from a load of volcanic ash settling into the sea – phytoplankton begins growing at a rapid rate, and blooms can rapidly cover hundreds of kilometers.
