Biological and Chemical Response of the Equatorial Pacific Ocean to the 1997-98 El Niño

• Published in: Science (American Association for the Advancement of Science) 1999-12, Vol.286 (5447), p.2126-2131
• Main Authors: Chavez, F. P., Strutton, P. G., Friederich, G. E., Feely, R. A., Feldman, G. C., Foley, D. G., McPhaden, M. J.
• Format: Article
• Language: English
• Subjects: Applied geophysics; Carbon dioxide; Chlorophylls; Earth sciences; Earth, ocean, space; El Nino; El Niño; Equatorial regions; Exact sciences and technology; External geophysics; Field Studies; Geochemistry; Internal geophysics; Marine; Marine biology; Mineralogy; Moorings; Nitrates; Ocean currents; Oceans; Physical and chemical properties of sea water; Physical Environment; Physics of the oceans; Silicates; Surface water; Thermoclines; Upwelling (Oceanography); Upwelling water; Water; Water geochemistry; Water levels
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.286.5447.2126

During the 1997-98 El Niño, the equatorial Pacific Ocean retained 0.7 × 10$^{15}$ grams of carbon that normally would have been lost to the atmosphere as carbon dioxide. The surface ocean became impoverished in plant nutrients, and chlorophyll concentrations were the lowest on record. A dramatic recovery occurred in mid-1998, the system became highly productive, analogous to coastal environments, and carbon dioxide flux out of the ocean was again high. The spatial extent of the phytoplankton bloom that followed recovery from El Niño was the largest ever observed for the equatorial Pacific. These chemical and ecological perturbations were linked to changes in the upwelling of nutrient-enriched waters. The description and explanation of these dynamic changes would not have been possible without an observing system that combines biological, chemical, and physical sensors on moorings with remote sensing of chlorophyll.