Ecosystem implications of Gulf Stream modes in the South Atlantic Bight

Poleward oceanic transport by the Gulf Stream is a prominent feature of outer shelf advection in the South Atlantic Bight. In the Carolina Capes region north of the Charleston Bump, the Gulf Stream alternates between two well-documented modes: a deflected seaward state with upper-slope recirculation (i.e., equatorward flows) and a shelf-slope attached state that produces smaller-scale frontal eddy activity. Although both states can impact shelf ecosystems, the distinct mechanisms of water mass mixing and export and the frequency of occurrence are not well-understood. As a precursor to an upcoming field program, we present a framework to decipher how alternating states can affect regional coastal ecosystems. This study also uses long-term satellite sea-surface temperature and Chlorophyll-a observations to empirically distinguish an ecosystem response and offer hypotheses related to circulation features within the two modes of variability. The frequency of occurrence, seasonal trends and frontal activity for the Gulf Stream modes are quantified. Their variation is then connected to measured phytoplankton blooms, the inferred flux of nutrients and seaward biomass export from the Carolina Capes continental shelf.

Presentation Preference: Either

Primary Presenter: Sutara Suanda, University of North Carolina Wilmington (suandas@uncw.edu)

Authors:

Sutara Suanda, University of North Carolina Wilmington  (suandas@uncw.edu)