Robert McEwan

Role
PhD Research Student  -  Interdisciplinary study of hydrodynamic and biogeochemical processes of a large-scale river plume 

Supervisors

           Dr. Vasyl Vlasenko
           Dr. Maeve Lohan
           Dr. Nataliya Stashchuk

A recent modelling study has shown the dynamics and mixing processes developing at the leading edge of the Columbia River plume are highly sensitive to the model input parameters and non-hydrostatic wave effects which have been ignored in most studies to date. These mixing processes are complex and understanding the processes that control the interaction of two water bodies is highly important as it controls all biogeochemical cycling in coastal areas.

The aim of this project is to study the mechanism of the Columbia River plume formation with emphasis on unstudied non-hydrostatic effects and to determine what processes enhance the cross margin transport of essential macro- and micronutrients resulting in a highly productive ecosystem.  The numerical work will be based on the state-of-the-art fully nonlinear non-hydrostatic three-dimensional Massachusetts Institute of Technology general circulation model (MITgcm). MITgcm will be used to reproduce numerically the plume dynamics in order to describe all important mechanisms developing during interaction of two water bodies and to provide a theoretical background for interpretation of the observational data on macronutrient and trace metal distribution.  After collation of macronutrient and trace metal data collected during 6 research cruises, the data will be divided into prevailing physical conditions during sampling such as upwelling, downwelling, spring tides and neap tides.  Then how the Columbia River plume affects the cross-margin transport of macro- and micronutrients will be determined. This will then be modelled using MITgcm to determine the extent to which the regional productivity differences are a result of the presence of the river plume - e.g., its turbidity, stratification, species composition and nutrient load, as well as its effect on mixing and advection.



Member of the Marine Physics Research Group

Member of the Biogeochemistry and Environmental Analytical Chemistry Resarch Group 

Qualifications & background
2008: MSc Applied Physical Oceanography, Bangor University

2005: BSc Marine Biology and Oceanography (2:1) , University of Wales, Bangor 

Professional membership
Member of the Challenger Society for Marine Science