Honors College


Nathan Shunk

Document Type

Honors Thesis


Marine Science


Andrew Thomas

Committee Members

Damian Brady, Williiam Ellis, Mark Haggerty, Mark Wells

Graduation Year

May 2021

Publication Date

Spring 5-2021


Nitrate, temperature, and salinity conditions in the coastal upwelling regions of the California Current System vary on decadal timescales due to El Nino Southern Oscillation (ENSO) cycles. This study examines the quarterly variations in these conditions over the period 1979 to 2018 for CalCOFI cross-shelf transect 80, located at Point Conception. The CalCOFI dataset was indexed by NOAA’s Multivariate ENSO Index version two, climatologies were formed over El Nino, La Nina, and neutral quarters and then anomalies were calculated from these climatologies. Variations are most predominantly visible in the upper 200m of the water column and can be seen both coastally and offshore. Nitrate and temperature varied the greatest in the second quarter, during the period of greatest upwelling. La Nina (El Nino) periods saw greater (lower) concentrations of nitrate in the surface coastal water column. The nitrate-density relationships were similar between El Nino, La Nina and neutral periods and a difference could not be determined.

Included in

Oceanography Commons