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Coastal Observations: A Biological Perspective
Images
Images: Satellite Images
Ocean Color and Satellite Imagery
When we think of the ocean, we think blue. However, it isn't just blue. The "color" of the ocean depends on the color of light reflected by the object in the water. Phytoplankton are the most significant constituents in determining the ocean color. Because phytoplankton contain chlorophyll, they absorbs light at blue and red wavelengths and backscatters the green. Because green is reflected back and that is why the ocean looks green in color. Also, when we look at the satellite image of the ocean, different shades of blue make up the ocean. These different colors may represent the concentrations of phytoplankton, sediments, and dissolved organic chemicals. Because different types of phytoplankton have different concentrations of chlorophyll, they appear as different colors to sensitive satellite instruments.
The principal oceanographic motivation for observing ocean color from space is to permit better understanding of the role of the ocean in the global carbon cycle. Variability in the optical properties of the ocean influences the color of the ocean as seen from space. For most of the ocean, the optical properties are controlled by the concentration of biogenic particles and dissolved matter like phytoplankton, bacteria, and their degradation products. Variations in the optical properties modify the spectral and geometrical distribution of the underwater light field, and thereby alter the color of the sea. Biologically rich and productive waters are characterized by green water. Some of the research uses of the ocean color will help to quantitatively specify the ocean's role in the global carbon cycle and other major biogeochemical cycles, and help determine the magnitude and variability of annual primary production by marine phytoplankton on both local and global scales, and their role in modifying the chemical and physical processes of the ocean and the atmosphere.
Chlorophyll a Levels
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Ocean Color and Chlorophyll a levels during the Summer (June 1998-August 1998) in the Northern Hemisphere. Use the scale below to determine Chlorophyll a concentration levels:
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Click the image above to enlarge.
A large mass of black water has swept through Florida Bay and according to reports, has broken up into smaller pockets aggregated along the north side of the 126-mile long Florida Keys. First seen in late December/early January, scientists have sampled the water in hopes of identifying the source of this event. The SeaWiFS image (above) taken on February 4, 2002 at the height of the event, clearly shows different colors of water in Florida Bay. It is interesting to compare the true color image with the SeaWiFS-derived chlorophyll image from 4 February with the true color and chlorophyll images taken on 21 March. In addition to the scientific interest in this phenomenon, there appear to be some serious ecological consequences, including the apparent impact on the coral reefs as well. Recent evidence points to the black water being associated with a large algal bloom fed by increased nutrient input from a land-based source. For the most up to date information on the event click here The development, growth and decline of the event can be seen in the images from 9 January, 4 February and 28 March 2002.
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Phytoplanton Blooms
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Click an image above to enlarge.
SeaWiFS images of Coccolithophorid Blooms in the Bering Sea (left) and the Celtic Sea (right)
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Click the image above to play movie.
The SeaWiFS instrument looks at the world oceans and land to observe the plant life and phytoplankton. Zooming down to the Congo River one can see how it affects the Ocean. Click on the image to see animation. Make sure you have Quicktime or Windows Media Player installed.
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Click the image above to enlarge.
The image above is a remotely sensed image taken by the SeaWifs Instrument aboard the SeaStar satellite. Here we see the Mid-Western to the Eastern United States with a focus on the Chesapeake Bay region.
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Phytoplankton Pigment Concentration
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Phytoplankton pigment concentration surrounding the East Coast of the United States.
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Water Temperature.
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The above images are provided by the SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGE.
