Seasonal and interannual variability in the flux of planktic foraminifera in the Humboldt Current System off central Chile (30°S)

Marchant,M.; Coloma C.; Hebbeln D.; Giglio S; González H.E.

Keywords: system, patterns, abundance, sediment, nino, regions, ocean, pacific, acquisition, seawater, variation, flux, sediments, world, data, trap, traps, foraminifera, oceanography, foraminifers, current, seasonal, El, Humboldt, oceanic, planktonic, Planktic, Globigerina, bulloides, Globigerinella, calida, Neogloboquadrina, dutertrei, pachyderma

Abstract

Seasonal and interannual changes in the flux of planktic foraminifers were studied in the Humboldt Current System off Coquimbo, Chile (30°S; 73°15?W), using material collected by time series sediment traps located at 2300 m water depth and 100 nautical miles from the coast. The almost continuous record spans 6 years (1993-1998) with a temporal resolution of 6-13 days. The seasonal flux pattern of planktic foraminifers was marked by high fluxes during austral late winter-early summer (August-January) and low fluxes during the fall-early winter period (March-July). Five species contributed ?90% of the total flux of planktic foraminifers: Globigerina bulloides, Neogloboquadrina incompta, N. pachyderma, N. dutertrei, and Globigerinella calida. Stable oxygen isotope variability in foraminifer shells appears to be driven by seasonal changes in surface seawater temperature; isotope data of G. bulloides and N. incompta (>212 and 150-212 ?m size classes) suggest that water-column stratification dominates during the low-flux period and mixing during the high-flux period. The strong 1997-1998 El Niño event had only a limited impact on the planktic foraminifer flux. The most significant El Niño-related signal was a remarkable increase in the flux and abundance of species that, under normal conditions, only accounted for <10% of the total planktic foraminiferal assemblage. © 2004 Elsevier Ltd. All rights reserved.

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Título de la Revista: DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
Volumen: 51
Número: 20-21
Editorial: PERGAMON-ELSEVIER SCIENCE LTD
Fecha de publicación: 2004
Página de inicio: 2441
Página final: 2455
URL: http://www.scopus.com/inward/record.url?eid=2-s2.0-9644290944&partnerID=q2rCbXpz