From Rivers to Reservoirs: reconstructing downstream sediment transport to the Red River Delta, Vietnam
The Red River in Vietnam supports 20 million inhabitants, includes a major rice-growing region, the mega-city of Hanoi and a range of industries each of which have expanded in recent decades. The Red River Delta (RRD) delta area of the river is the agricultural heartland of the region and provides crucial ecosystem services, including the retention and removal of nutrients and pollutants for groundwater (drinking water) and marine resource protection, carbon processing and flood protection. The Hoa Binh and Thac Ba reservoirs are major impoundments upstream of the RRD, estimated to be responsible for trapping substantial amounts of sediment, with major consequences for the delta and downstream coastal zone. Mean discharge has reduced in tandem with reduced suspended sediment (SS) transport, which together with sea level rise has contributed to an increased risk of saline water intrusion in the RRD. This PhD project aims to reconstruct, how dam installation has altered macro-nutrient (phosphate[P], nitrate[N] and silicate[Si]) and SS load delivery to the RRD, as a means to better inform reservoir management under increased downstream water resource demand and climate change threats in the region. Via the collection and dating of Hoa Binh and Thac Ba reservoir sediment cores (210Pb, 137Cs), this project will quantify changes in sediment accumulation rate since dam construction. Particle size analyses, sediment elemental analyses (ICP-MS), algal pigment biomarkers, diatom flora, biogenic silica quantification (alkaline digestion) and stable isotope approaches (δ13C, δ15N and C/N) will also be applied to reconstruct alterations in nutrient biogeochemical cycling and N:P:Si stoichiometry. Together, these approaches will permit the reconstruction of sediment and nutrient retention in the reservoirs (since installation) and estimate downstream delivery impacts to the RRD over time. This project provides the opportunity to conduct fieldwork in Vietnam and via co-supervision at BGS, to learn key analytical principles here.
All applicants should hold a minimum of a UK Honours Degree at 2:1 level in a subject area including Geography (BSc), Environmental Science, Natural Science or Geosciences. A basic understanding of limnology and the field and laboratory methods suited to this study are expected (e.g. water chemistry). Applicants should have experience in the theory or application of stable isotope techniques and/or palaeolimnological methods (e.g. sediment dating, core lithology, diatom flora). Some knowledge in statistical analysis and interpretation of data, along with knowledge of multivariate practices is also welcomed.
For further enquiries please contact Dr. Virginia Panizzo at the School of Geography,
University of Nottingham via email: firstname.lastname@example.org.