El Niño–Southern Oscillation Diversity: Effect on Upwelling Center Intensity and Its Biological Response

• Published in: Journal of marine science and engineering 2024-07, Vol.12 (7), p.1061
• Main Authors: Gutiérrez-Cárdenas, Gabriel Santiago, Morales-Acuña, Enrique, Tenorio-Fernández, Leonardo, Gómez-Gutiérrez, Jaime, Cervantes-Duarte, Rafael, Aguíñiga-García, Sergio
• Format: Article
• Language: English
• Subjects: Anomalies; Biodiversity; Biogeochemistry; Biological effects; Biomass; California Current System; central Pacific El Niño; coastal upwelling; Coasts; Coherence; Ecological effects; Ekman transport; El Nino; El Nino phenomena; equatorial Pacific El Niño; Hypotheses; Mexico; northern Pacific meridional mode; Ocean circulation; Plankton; Productivity; Regional development; Regions; Sea surface; Southern Oscillation; Surface water; Upwelling; Wind
• ISSN: 2077-1312; 2077-1312
• DOI: 10.3390/jmse12071061

The influence of El Niño–Southern Oscillation (ENSO) on productivity at upwelling systems has been extensively studied. However, in recent decades, ENSO diversity has been documented; there are more frequent events with anomalies in the central Pacific (CP) causing ecological impacts that are different from the canonical events centered in the eastern Pacific (EP). We hypothesize that ENSO effects on upwelling intensity and its biological response are highly dependent on ENSO diversity. Wavelet coherence was computed for monthly standardized anomalies of Ekman transport and sea surface Chlorophyll-a (Chl-a) concentration from eight upwelling centers located along the west coast of the Baja California peninsula (1993–2022). Ekman transport (ET) showed a non-linear association with ENSO at interannual periodicities between 1.2 and 7 years, as well as semiannual scale variability. Coherence between ENSO and ET showed a reduction in upwelling intensity during CP ENSO events and an increased upwelling intensity after EP El Niño events with regional differences. Our results reveal an influence of northern Pacific circulation that subsequently influences ENSO events during its development and its peak. We detected an influence of SST and wind anomalies on the ENSO–Ekman transport connection associated with the northern Pacific Meridional Mode pattern. The CP shows an important role in sea surface Chl-a concentration anomalies (1998–2022). We highlight the conceptual relevance of distinguishing ENSO diversity, with influential ecological effects associated with CP ENSO events.