Rapid reorganization in ocean biogeochemistry off Peru towards the end of the Little Ice Age

2009

Article référencé dans le Web of Science WOS:000266556300008

Gutierrez D., Sifeddine Abdelfettah, Field D. B., Ortlieb Luc, Vargas G., Chavez F. P., Velazco F., Ferreira V., Tapia P., Salvatteci R., Boucher Hugues, Morales M. C., Valdes J., Reyss J. L., Campusano A., Boussafir M., Mandeng Yogo Magloire, Garcia Marta, Baumgartner T.

Biogeosciences, 2009, 6 (5), p. 835-848 ISSN 1726-4170

Climate and ocean ecosystem variability has been well recognized during the twentieth century but it is unclear if modern ocean biogeochemistry is susceptible to the large, abrupt shifts that characterized the Late Quaternary. Time series from marine sediments off Peru show an abrupt centennial-scale biogeochemical regime shift in the early nineteenth century, of much greater magnitude and duration than present day multi-decadal variability. A rapid expansion of the subsurface nutrient-rich, oxygen-depleted waters resulted in the present-day higher biological productivity, including pelagic fish. The shift was likely driven by a northward migration of the Intertropical Convergence Zone and the South Pacific Subtropical High to their present day locations, coupled with a strengthening of Walker circulation, towards the end of the Little Ice Age. These findings reveal the potential for large reorganizations in tropical Pacific climate with immediate effects on ocean biogeochemical cycling and ecosystem structure.

Sciences du milieu [021] ; Géologie et formations superficielles [064]

Fonds IRD [F B010046139]

fdi:010046139