Tim Dixon

Tim Dixon

Profile

  • 2015 - present: PhD at University of Leeds
  • 2013 - 2015: Graduate Environment Advisor at Costain; Programmes Assistant and Adventure Leader at British Exploring
  • 2009 - 2013: Integrated Masters (MGeol) in Environmental Geology at the University of Leeds including year abroad at University of California, Santa Barbara

Follow me on Twitter @Tim_J_Dixon

My Researchgate profile

Memberships:

  • Association of Polar Early Career Scientists
  • UK Polar Network
  • European Association of Geochemistry
  • Mineralogical Society

Research interests

NERC DTP Funded Project: Geogenic Nitrogen as a nutrient source in subglacial microbial ecosystems

Subglacial systems have recently been shown to harbour active microbial populations that mediate biogeochemical weathering reactions. However these are severely nutrient-limited ecosystems. One source of ammonium as a nutrient in these systems is released from phyllosilicates and feldspars as bedrock is comminuted into silt during glacial erosion.

This project will use experimental simulations to establish:

  1. i) the magnitude of this contribution from different bedrock lithologies;
  2. ii) N speciation and isotope effects during this process;

iii) N-isotopic signature of N species released during weathering of different lithologies.

The project will focus initially on various glacial catchments near Longyearbyen, Svalbard. Fieldwork involves collecting both rock and subglacial water to measure concentrations of N species as well as isotopes of nitrate. This project will thus constrain the release of geogenic N and its impact on this sub-glacial ecosystem.

This research will allow us to better understand controls on bio-limiting nutrient (N) and organic carbon fluxes (microbes) from the cryosphere, and how these influence global biogeochemical cycles and climate change on glacial-interglacial timescales.

Smith, M. W., D. J. Quincey, T. Dixon, R. G. Bingham, J. L. Carrivick, T. D. L. Irvine-Fynn, and D. M. Rippin (2016), Aerodynamic roughness of glacial ice surfaces derived from high-resolution topographic data, J. Geophys. Res. Earth Surf., 121, 748766, doi:10.1002/2015JF003759.

Qualifications

  • PhD, University of Leeds (currently studying)
  • MGeol, Environmental Geology, University of Leeds

Research groups and institutes

  • Earth Surface Science Institute
  • Cohen Geochemistry