Though these aquamarine clouds in the waters off the coast of northern Namibia
may look like algae blooms, they are in fact clouds of sulfur produced by
anaerobic bacteria on the ocean’s floor. This image of the sulfur-filled water
was taken on April 24, 2002, by the Sea-viewing Wide Field-of-View Sensor
(SeaWiFS), flying aboard the Orbview-2 satellite.
The anaerobic bacteria (bacteria that can live without oxygen) feed upon
algae carcasses that exist in abundance on the ocean’s floor off of Namibia. As
the bacteria ingest the algae husks, they produce hydrogen sulfide, which slowly
builds up in the sea-floor sediments. Eventually, the hydrogen sulfide reaches
the point where the sediment can no longer contain it, and it bubbles forth.
When this poisonous chemical reaches the surface, it combines with the oxygen in
the upper layers of the ocean to create clouds of pure sulfur. The sulfur
causes the Namibian coast to smell like rotten eggs, and the hydrogen sulfide
will often kill fish and drive lobsters away.
For more information, read: A Bloom By Any Other Name
A high-resolution (250 meters per pixel) image earlier on the 24th taken from
the Moderate-Resolution Imaging Spectroradiometer (MODIS) shows additional detail
in the plumes.
Image courtesy the SeaWiFS Project,
NASA/Goddard Space Flight Center, and ORBIMAGE. MODIS image courtesy
Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC