Fine scale mapping of the structure and composition of the Elkhorn Slough (California, USA) tidal plume
Fischer, AM and Ryan, JP and Rienecker, EV, Fine scale mapping of the structure and composition of the Elkhorn Slough (California, USA) tidal plume, Estuarine, Coastal and Shelf Science, 184 pp. 10-20. ISSN 0272-7714 (2017) [Refereed Article]
Fine scale mapping of the structure and composition of a tidal ebb plume from a highly modified coastal
lagoon (Elkhorn Slough, California, USA) was conducted by combining in situ, observational data sets
from surface underway mapping, autonomous underwater vehicle (AUV) profiles, drifter tracking and
the analysis of plume structure indices. The results reveal a 6-m-deep, jet-like, sediment laden plume
extending one km offshore at low tide, which becomes entrained in the prevailing nearshore circulation.
The plume that exits the slough is significantly different from the water that enters the slough. The
rapidly evolving discharge plume is associated with elevated and highly correlated (r = 0.93) concentrations
of dissolved organic matter and nitrate. While dissolved constituents remain in the shallow
plume and are transported northward with the prevailing current, sediment may settle quickly through
the water column and can be transported southwestward with the littoral currents. This study illustrates
the applications of AUVs, when coupled with additional datasets, for generating higher resolution
observational snapshots of dynamic and ephemeral tidal plumes. The results provide unique perspective
on small-scale dynamics of an estuarine plume and its influence on coastal ecology.