Abstract

JUAREZ, Miryam; SANCHEZ, Alberto  and  GONZALEZ-YAJIMOVICH, Oscar. Variability of marine biological productivity in the northeastern Pacific over the past millennium. Cienc. mar [online]. 2014, vol.40, n.4, pp.211-220. ISSN 0185-3880.  https://doi.org/10.7773/cm.v40i4.2477.

In this study we present new data of biogenic opal (BO), organic carbon (OC), and calcium carbonate (CaCO₃) in a high-resolution record from the western coast of Baja California Sur, Mexico. The variability of marine biological productivity in this area is dominated by El Niño and La Niña events on different time scales. The BO and OC contents showed a decrease between AD 1100 and 1400. From AD 1400 to the present, BO and OC showed a significant increase, indicating permanent upwelling conditions. The CaCO₃ content showed an inverse correlation with OC, which suggests that the exported OC fluxes are a significant factor controlling CaCO₃ dissolution in the sediment. The increase in BO and OC was synchronic with a decline in the number of El Niño events (6 ± 4 every 100 years) over the last 600 years of the millennium.

Keywords : biogenic opal; organic carbon; El Niño; La Niña; upwelling.

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