Open AccessOxygen isotope record of the 1997–1998 El Niño in Peruvian sea catfish ( Galeichthys peruvianus ) otoliths
Author(s) -
Andrus C. Fred T.,
Crowe Douglas E.,
Romanek Christopher S.
Publication year - 2002
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1029/2001pa000652
Subject(s) - otolith , isotopes of oxygen , oceanography , aragonite , geology , δ18o , seawater , sea surface temperature , stable isotope ratio , mineralogy , calcite , fishery , geochemistry , biology , fish <actinopterygii> , physics , quantum mechanics
Sagittal otoliths of the Peruvian sea catfish Galeichthys peruvianus were collected from the north coast of Peru during and after the 1997–1998 El Niño. The otoliths were analyzed via laser microprobe and micromilling techniques for oxygen isotope composition through ontogeny to document their use as an El Niño‐Southern Oscillation (ENSO) proxy. Results were compared to theoretical calculations for the δ 18 O of otolith aragonite using measured sea surface temperatures (SST) and δ 18 O values for local seawater assuming equilibrium oxygen isotope fractionation was achieved. All otoliths recorded the 1997–1998 El Niño event as well as seasonal temperature variations. These ENSO events were recorded in otolith aragonite as significant negative excursions in δ 18 O that reflected the increased temperature of local marine waters. The combined otolith data were used to create a 10‐year SST record, including ENSO events and local seasonal temperature variation, validating the use of otolith δ 18 O as a temperature proxy.