Oceanography and its effects on the Galápagos Islands By Morgan Ling

Galápagos Islands Archipelago of volcanic islands Located between 89°W and 92°W along the equator Known for its vast number of unique species studied by Darwin

Surrounding Current System Galápagos platform located ~3000 ft below sea level Average depth surrounding islands: ~9900 ft Tropical Mix of water temp & salinity, productivity Cooler Warm-temperate Higher salinity Higher chlorophyll content

Upwelling

How Does Upwelling Occur? I. Along coastlines Coriolis effect in South Hemisphere Humboldt Current II. Along the equator No Coriolis force Trade winds from north east and south east (Inter-Tropical Convergence Zone) Cromwell Current III. Around the Islands As seafloor becomes shallower – forces deeper ocean currents to surface

Upwelling Effects Cold water rich with nutrients Nitrate and phosphate Nutrients & sunlight important for phytoplankton and algae Primary producer of ecosystem Key to food production

El Niño-Southern Oscillation (ENSO) Warm current that moves in southward direction Occurs every 2-15 years around December Approx. every 7 years: Humboldt Current interrupted by El Niño Upwelling stopped Water temp inc. Cold water species forced to migrate

Effects of ENSO Winter of 1997/98 Increased rainfall & temperature Beneficial for some terrestrial plants Marine life negatively affected Sea Lions suffered b/c lack of sardines Marine Iguanas suffered b/c of a decrease of green algae Many fish specifies found in deeper waters

A Brief Overview About the Marine Life Galápagos marine ecosystem is considered intermediate-to-high in terms of species richness ~3000 species of marine plants & animals 21% found no where else on Earth Many scientific expeditions occurred focusing on fish and other marine life Different fish species exceeds 400 Wide range of habitats located in the Galápagos, including mangroves, rocky shores and sandy bottoms

Works Cited "Upwelling - Discovering Galapagos." Discovering Galapagos. Discoveringgalapagos, n.d. Web. 02 Dec. 2015. "El Niño - Discovering Galapagos." Discovering Galapagos. N.p., n.d. Web. 02 Dec. 2015. Fitz, John M. "Oceanography and Marine Life of the Galápagos Islands." Oceanography and Marine Life of the Galápagos Islands. University of Maryland, n.d. Web. 02 Dec. 2015. "Galápagos Islands -- World Heritage Site -- National Geographic." National Geographic. National Geographic, n.d. Web. 02 Dec. 2015. Knauss, J.A., 1997, Introduction to Physical Oceanography, Waveland Press, Inc., Illinois, 146-151pp.