HR: 11:00h
AN: U32A-03    [Abstracts]
TI: The Incredible Shrinking Iguana: Impact of Galapagos
AU: * Murtugudde, R
EM: ragu@essic.umd.edu
AF: ESSIC-University of Maryland, 2207 CSS Bldg ESSIC University of Maryland, College Park, MD 20742, United States
AU: Karnauskas, K
EM: kris@essic.umd.edu
AF: ESSIC-University of Maryland, 2207 CSS Bldg ESSIC University of Maryland, College Park, MD 20742, United States
AB: Galapagos Islands are well known for Darwin's epiphany about evolution after his 'discovery' of the islands. The incredible transformation that the key species on this island undergo on ENSO time-scales is recorded extensively. The impact of Galapagos on SSTs and ocean primary production has been conjectured but some recent work demonstrates that their influence extdends thousands of kilometers via stronger TIWs and modulations of the termination of EUC and related air-sea interactions. Tropical Pacific is not only the theater of action for ENSO dynamics but the ecosystem is the most studied iron limited region due to its HNLC characteristics. This study addresses the physical and biogeochemical impacts of the Galapagos islands with a OGCM-biogeochemical model coupled to a simple wind-anomaliy model. The impact of Galapagos is to warm the cold-tongue by upto 1C with a major impact on the termination of the EUC that results in large-scale circulation changes that extend to the South American coast as far south as 20S. If the islands are not included, then the equatorial Kelvin waves extend their impact on thermocline variability all the way to the eastern boundary and lead to a quasi-biennial ENSO whereas the impact of Galapagos islands shifts the frequency to a quasi- quadrennial time-scale. The impacts on the ecosystem are commensurate with the seasonal and interannual variability changes with the addition of dissolved iron supply related to EUC changes. Bio-physical feedbacks in the deep tropical Pacific also tend to warm SSTs and the impact of Galapagos is thus to flatten the east-west SST gradient resulting in less-frequent and weaker ENSO events. The relevance of these results to longer time-scale variability and any potential analogs to global warming and sea level change are discussed in detail.
DE: 1610 Atmosphere (0315, 0325)
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 3610 Geochemical modeling (1009, 8410)
DE: 4231 Equatorial oceanography
DE: 4806 Carbon cycling (0428)
SC: Union [U]
MN: 2007 Joint Assembly