Monday, September 21, 1998 Published at 13:35 GMT 14:35 UK
Oceans seen from space
The oceans seen on a global scale
Nasa has released dramatic images showing the Earth's changing oceans, as observed from space for one year. Our science editor Dr David Whitehouse reports
The images were obtained by the SeaWiFS satellite which was launched on August 1st 1997.
Its main task is to monitor the oceans. It carries a range of sensors to analyse the oceans colour - an indicator to the type and quantity of life it contains.
Among the highlights of its first continuous year of observation have been new insights into the impact of the El Niño effect on ocean life.
El Nino is the periodic change in circulation in the Pacific Ocean. Warm currents from the western Pacific disrupt weather patterns causing global changes.
It was also able to monitor a variety of natural disasters,including fires in Florida: floods in China; dust storms in the Sahara and Gobi Deserts; and the progress of hurricanes, such as Bonnie and Danielle.
SeaWiFS has also enabled scientists to witness the transition from El Niño to La Niña conditions in the Equatorial Pacific.
What has surprised scientists is the speed at which the ocean returned to its pre-El Niño state.
La Nina, sometimes called El Nino's angry sister resulted in unprecedented phytoplankton growth in the oceans.
Phytoplankton are microscopic marine plants that remove carbon dioxide from the atmosphere.
Scientists are keen to understand this exchange of carbon dioxide and the role it plays in the global climate.