G02_P06

Long Term Time Series of Surface Water Dissolved Inorganic Carbon Isotopes from the Southern California Bight

Hauksson N¹,  Griffin S¹, Xu X¹, Martinez H¹, Pedron S¹, Druffel E¹

¹University Of California, Irvine, Irvine, United States

The Southern California Bight is an oceanographically complex region in a Mediterranean climate, strong upwelling, and limited rainfall. The health of kelp forests and marine protected areas in these waters depend on the balance of waters from wind-driven upwelling, the California current, and the California counter-current. Water mass tracers, such as carbon isotopes, inform the movement of water masses in this region. We report dissolved inorganic carbon (DIC) ∆¹⁴C and 𝛅¹³C values in seawater collected from the Newport Beach Pier in Orange County, California from 2011 to 2022. The ∆¹⁴C values decrease over this period, consistent with depletion of the ¹⁴C generated by thermonuclear weapons testing and dilution of ¹⁴C-free CO₂ from fossil fuel combustion. We analyze the relationship of these isotopes with the environmental conditions during this time series.