Dr Robyn Tuerena BSc PhD

My current research aims to reconcile the apparent mismatch in nutrient supply and export production within the subtropical North Atlantic. Here at the University of Liverpool we are investigating whether the mid Atlantic Ridge topography may cause enough turbulence to mix nutrients upward through the water column. This may supply nutrients to lighter isopycnals within the water column to sustain nutrients within the upper thermocline and support primary production downstream.

We are investigating this with observational work over and adjacent to the ridge, using high resolution measurements of nutrients and turbulence on an oceanographic cruise (May-July 2016), these data will be combined with long term mooring data of internal tide characteristics and upper ocean oxygen and nitrate cycling.

As part of my PhD I studied the functioning of the modern marine nitrogen cycle.

To do so I used geochemical approaches to investigate the biogeochemical cycling of nitrogen and carbon within the Atlantic Ocean. Nitrogen is the principle limiting nutrient to algae within most of the world’s oceans, which highlights the importance in understanding the sources and sinks of N and the implications on marine productivity.

My main focus was to collect and measure samples across a transect in the South Atlantic Ocean at 40 degrees S, as part of the UK GEOTRACES programme. I measured the isotopic ratios in nitrate within deep water masses to investigate the role of both preformed and remineralized nutrients within the Atlantic ocean.

Within my PhD I worked on the development of the Denitrifier Method (Sigman et al., 2001, Casciotti et al., 2002) at the Scottish Universities Environmental Research Centre and at the University of Edinburgh.

This work was funded through the UKGEOTRACES programme.

www.ukgeotraces.com