Ph.D. Proposal Defense: David Marshall

The Ph.D. Proposal Defense of David Marshall will be presented at UNC IMS (Institute of Marine Science) seminar room 222 in Morehead City – NC, streamed to Murray Hall, room 3204 of the Marine Sciences Department, UNC at Chapel Hill. Held on Friday, December 9th, 2016 at 9:00 AM.

Title: Turbulent mixing, circulation and salt transport in a strongly stratified, microtidal, wind-driven estuary.

Abstract: In estuaries, tides are considered to be the dominant mechanism driving the mixing of freshwater from rivers with the saline waters from the adjoining ocean, hence determining the along-estuary salinity gradient and strength of estuarine circulation. However, there are a number of microtidal estuaries, in which it is the wind that is the dominant forcing mechanism. These estuaries are prone to human-induced water quality problems as the episodic nature of wind leads to less vertical mixing and strong stratification, which when combined with eutrophication results in bottom-water hypoxia. The proposed work aims to further our understanding of turbulent mixing, circulation and salt transport in these wind-driven estuaries, which are currently poorly understood. Through field measurements collected in the Neuse River Estuary in 2013 and 2016, I will investigate (1) the nature of turbulence generated by stably stratified shear flows, (2) the mechanisms for vertical mixing in the absence of tides, and (3) the effects of time-varying wind, unsteady winds on circulation and salt transport.