Volcanic Ash Fuels Phytoplankton Bloom
Contributed by Roberta C. Hamme | Saturday, Nov 13, 2010

In August 2008, ash from the explosive eruption of Kasatochi Volcano in the Aleutian Islands (marked by the white triangle) not only snarled air travel in the region, it also fueled phytoplankton growth on an unprecedented scale. A storm system moving across the North Pacific swept up the airborne ash and deposited it over a large area of the ocean, as shown in the bottom left image. The ash from the volcano provided iron to the ocean, which stimulated phytoplankton growth. Phytoplankton are microscopic oceanic plants that account for roughly half of all photosynthesis on Earth. In about one-fifth of the world's oceans, including the northern North Pacific, phytoplankton have less iron then they need to effectively grow. The iron provided by the Kasatochi ash led to a vast "bloom" of phytoplankton over an area about one-quarter the size of the continental United States, the largest ever seen in this part of the ocean. Comparing the images at the top from August 2007 (a normal year) and 2008 shows the area of unusually high chlorophyll, marking the bloom, which corresponds well to the area covered by the volcanic ash. Data from many types of oceanographic measurements were used to record and understand this unusual event.

Caption by Open-Ocean Staff and Roberta C. Hamme
This material is based upon work supported by the Natural Sciences and Engineering Research Council of Canada This material is based upon work supported by the Natural Sciences and Engineering Research Council of Canada under Grant No. DG 34816-57300 | Disclaimer Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Natural Sciences and Engineering Research Council of Canada | Hide
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