The findings are from a NASA-funded analysis of data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument on the OrbView-2 spacecraft, launched in 1997. The uninterrupted nine-year record shows in great detail the ups and downs of marine biological activity or productivity from month to month and year to year. Captured at the start of this data record was a major, rapid rebound in ocean biological activity after a major El Nio event. El Nio and La Nia are major warming or cooling events, respectively, that occur approximately every three to seven years in the eastern Pacific Ocean and are known to change weather patterns around the world.
Scientists made their discovery by comparing the SeaWiFS record of the rise and fall of global ocean plant life to different measures of recent global climate change. The climate records included several factors that directly affect ocean conditions, such as changes in sea surface temperature and surface winds. The results support computer model predictions of what could happen to the world's oceans as the result of prolonged future climate warming.
"When we compared changes in phytoplankton activity with simultaneous changes in climate conditions, the agreement between the two records was simply astonishing," Behrenfeld said.
Ocean plant growth increased from 1997 to 1999 as the climate cooled during one of the strongest El Nio to La Nia transitions on record. Since 1999, the climate has been in a period of warming that has seen the health of ocean plants diminish.
The new study also explains why a change in climate produces this effect on ocean plant life. When the climate warms, the temperature of the upper ocean also increases, making it "lighter" than the denser co
Contact: Gail Gallessich
University of California - Santa Barbara