|Plankton Bloom, Capricorn Channel, Australia:
This image captures a plankton bloom in the Capricorn Channel off the Queensland coast of Australia. The whispy pattern of the bloom suggests that the plankton are Trichodesmium—a photosynthetic cyanobacteria, also called “sea saw dust” that is common in the world’s oceans. Trichodesmium species are particularly important because of their role as primary producers: by sheer abundance, they fix a large amount of CO2 and N2
Astronauts frequently photograph large plankton blooms during their missions because a significant portion of the ISS orbits cross long stretches of ocean. In the process, astronauts become acute observers of subtle changes in sea surface dynamics. Astronauts are trained and encouraged to document phytoplankton blooms, and to make repeated observations to better understand the longevity and temporal variations of the blooms.
Why is this image unique?: These images provide more resolution of blooms than is available in other satellites monitoring ocean primary productivity. Each pixel in this image represents a square area of ocean with sides of 6-8 m. Scientists use images like this one to try and understand the interaction between ocean dynamics and plankton blooms. One ongoing study in the Gulf of Maine is coordinating detailed ISS observations with field transects and using both as information to validate data from the SeaWiFS sensor.
ISS005-E-21572, 27 November 2002, 800 mm lens
The Gateway to Astronaut Photography of Earth, http://eol.jsc.nasa.gov
Yoder JA, Ackleson SG, Barber RT, Flament P, Balch WM. A line in the sea. Nature 1994; 371:689-92.