Sunlit surface waters teem with billions and billions of tiny algae called phytoplankton. These photosynthesizers capture energy from sunlight and carbon dioxide from the atmosphere and sea water, and support most marine food webs. (On land, the major photosynthesizers are grasses and trees.)
Food Web Illustration (coming soon)
Photosynthetic algae thrive in the bright light and nutrients of the ocean's upper layer. Consequently, other animals, including the fish we eat, congregate there to graze or hunt. By checking satellite images for changes in sea-surface color produced by large colonies of algae, fishermen can often find large concentrations of fish.
Food webs on land generally have few links: an insect eats grass, a mouse eats the insect, a snake or hawk eats the mouse. In the ocean, some food webs become long and complex.
Diatoms, photosynthetic
algae of many sizes and shapes but mostly microscopic,
with shells of silica, are among the oceans' primary producers--the
first and most vital link in food webs §.
photo
© Oxford Scientific Films/Animals Animals
Copepods are the most numerous of grazers in the oceans--they may even be the most
numerous multicellular animals on earth §. Most of them are filter feeders that scoop up
diatoms and other phytoplankton.
photo © Peter Parks, Norbert Wu
Surface dwellers: goose barnacles, Spirula shell, Portuguese man-of-war. Many larval
forms of bottom-dwellers spend early stages of their lives near the surface. A variety of
environmental cues tell them when it's time to settle down.
photo © Peter Parks/Animals Animals
Ocean Planet Exhibition Floorplan
gene carl feldman (gene@seawifs.gsfc.nasa.gov) (301) 286-9428 Judith Gradwohl, Smithsonian Institution (Curator/Ocean Planet)