|
Author:
|
Gutiérrez, D.; Sifeddine, A.; Field, D. B.; Ortlieb, Luc; Vargas Easton, Gabriel; Chávez, F. P.; Velazco, F.; Ferreira, V.; Tapia, P.; Salvatteci, R.; Boucher, H.; Morales, M. C.; Valdés, J.; Reyss, J.-L.; Campusano, A.; Boussafir, M.; Mandeng Yogo, M.; García, M.; Baumgartner, T.
|
|
Abstract:
|
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 ofWalker 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. |