Images & Animations
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Credit
Mark Abbott, Ricardo Letelier, and Jasmine Bartlett, Oregon State University
Chlorophyll-a (Chl)
This image from March 1, 2000, shows chlorophyll concentrations as measured by MODIS in the Indian Ocean. Chlorophyll, the green pigment in plants and phytoplankton, absorbs sunlight for use in photosynthesis. Note the high concentrations (warmer colors) in the Arabian Sea and relatively low concentrations (cooler colors) in the Bay of Bengal. The black color in the image represents land areas and gaps between successive satellite orbits and the gray color indicates where clouds or sun glint prevented accurate measurements.
Fluorescence Line Height (FLH)
MODIS can also measure chlorophyll fluorescence. Phytoplankton re-emit some of the light that is captured by chlorophyll as fluorescence in the red portion of the spectrum. The amount of fluorescence is roughly proportional to the amount of chlorophyll, so we see high fluorescence in the Arabian Sea.
FLH/Chl Ratio
There is much variability in the amount of fluorescence per unit of chlorophyll. This variability is largely a function of the health of the phytoplankton. This image shows the ratio of fluorescence to chlorophyll from MODIS. A high ratio implies lower growth rates. That is, light is being captured by phytoplankton but they are re-emitting it as fluorescence rather than using it for photosynthesis. The cooler colors represent higher growth rates. Phytoplankton in the Arabian Sea are probably growing more rapidly than elsewhere, perhaps in response to dust inputs (which are rich in iron) from the Arabian Peninsula.
(MODIS Data Type: MODIS-PFM & SeaWiFS)
Metadata
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Sensor
Terra/MODIS -
Visualization Date
2000-05-09
