Monthly to Decadal Variability of Mesoscale Stirring in the California Current System: Links to Upwelling, Climate Forcing, and Chlorophyll Transport

Abstract

Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems in the world (Pauly & Christensen, 1995). This high production is enabled by the wind-driven upwelling of nutrient-rich water from depth into the euphotic zone, which stimulates new primary production. This in turn supports dynamic food webs and economically important fisheries. The upwelled water is acted upon by physical forces-advected away from the point of upwelling, subducted away from the euphotic zone, or mixed into other water masses. In EBUS, horizontal stirring-the kinematic mixing of water masses and tracers driven by the flows associated with fronts, filaments, and eddies, and their interactions-moves upwelled water away from its coastal origin, increasing the input of nutrient-rich and high chlorophyll water to oligotrophic waters offshore, while reducing the availability of this nutrient-rich water inshore (Gruber et al., 2011;Rossi et al., 2009). Because of its impact on the spatial

Phytoplankton Patches at Oceanic Fronts Are Linked to Coastal Upwelling Pulses: Observations and Implications in the California Current System

“…Wind‐driven coastal upwelling occurs within a narrow band along the coast (Jacox & Edwards, 2012; Rykaczewski & Checkley, 2008), though regions of wind‐stress curl upwelling can extend up to 200–300 km offshore (Pickett & Paduan, 2003). Upwelling is temporally and spatially dynamic in this region (Chelton, 1982; Giddings et al., 2022; Rykaczewski & Checkley, 2008). Mesoscale stirring, driven by a patchwork of filaments and eddies, contributes to the lateral transport of biological productivity away from the upwelling zone (Amos et al., 2019; Chabert et al., 2021; Nagai et al., 2015; Zaba et al., 2021).…”

Petrale sole transboundary connectivity and settlement success: a biophysical approach

“…Petrale sole are an excellent candidate for mechanistic investigations into oceanographic drivers of recruitment strength because 1) the petrale sole data available for the U.S. waters of the CCS are information-rich, due to the large amount of age and length data that spans multiple generations, 2) petrale sole spawn at well known, localized locations during winter, 3) the U.S. stock assessment model, and thus recruitment estimates, is highly stable, and 4) both previous fisheries and oceanographic research suggests clear, untested, mechanisms for oceanographic drivers of petrale sole early life history transport and recruitment (Haltuch et al, 2013). In eastern boundary current systems, such as the CCS, the impacts of large-scale processes on biological dynamics of marine resources can be evaluated through the analysis of the spatial and interannual variability of mesoscale and submesoscale structures (Keister and Strub, 2008;Giddings et al, 2022), such as meanders, filaments and eddies, where for the former is already implemented automatic procedures for its identification and tracking (Halo et al, 2014). Thus, this study tests two hypotheses regarding oceanographic transport during petrale sole early life history stages.…”