Adam Francis

        Picture of Adam Francis

PhD student

I am a geochemist with expertise in riverine and oceanic environments and a particular interest in the nitrogen cycle. I utilise nitrogen isotopes to help understand the processes controlling nitrogen fixation and future changes to the marine nitrogen cycle in the North Atlantic and Mediterranean.

Contact details:

Controls on nitrogen fixation in the subtropical North Atlantic Ocean and the Mediterranean Sea

Over most of the global ocean, fixed nitrogen (N) is the primary limiting nutrient to phytoplankton. The marine N reservoir undergoes large natural fluctuations from N loss in suboxic regions (denitrification) and N addition by N2 fixing organisms. Our current understanding of how susceptible the marine N cycle may be to future increases in N through atmospheric deposition and N loss due to ocean deoxygenation/ denitrification is incomplete. Changes to these processes may potentially alter the marine N inventory with implications to global primary productivity in the future.

My project aims to explain the controls on N2 fixation in the low latitude ocean, specifically the Atlantic basin which has high N2 fixation rates due to being well-oxygenated with a high Fe supply from Saharan dust. However, sustained N2 fixation requires dissolved phosphorus (P). I am specifically investigating how tightly dissolved N/P nutrient ratios control N2 fixation by focusing on the subtropical North Atlantic Ocean and Mediterranean Sea. 

Research questions

How do dissolved N/P nutrient ratios impact N2 fixation in the North Atlantic ocean?

How important is N2 fixation in the Mediterranean?

How will climate change affect global N2 fixation rates and what are the implications to the marine N inventory?



Dr Robyn Tuerena, SAMS

Prof Raja Ganeshram - The University of Edinburgh






The University of Edinburgh

Teaching Experience

Two years of experience teaching undergraduate students in laboratory and fieldwork settings over a range of subjects including geochemistry, geology, ecology and oceanography. 


Fieldwork experience

I have extensive field work experience onboard scientific research vessels. Expeditions include Svalbard and the Greenland Sea with the Norwegian Polar Institute and along the coastline of Northern Russia with the Russian Academy of Sciences. I worked as part of a team of geochemists, collecting water and sediment samples for nutrient and isotopic analysis.


2021 - Research Assistant in Soil Biogeochemistry , University of Edinburgh

2019-2020 - Laboratory Technician, University of Edinburgh


Higher Education

2020 - MScR Riverine Geochemistry, University of Edinburgh

2018 - BSc (Hons) Environmental Geoscience, University of Edinburgh