I joined Heriot-Watt University in 2017. Before this I worked as a postdoc at several institutions.

2011- 2016 (& maternity leave and working part-time) NERC Fellowship "Deep ocean oxygen concentrations and efficiency of the biological pump". Department of Earth Sciences, University of Oxford, collaborating with Prof Ros Rickaby. Development of new, and improvement of existing, proxy methods to reconstruct past oxygen contents in seawater, using the calcite tests of marine fossil unicellular organisms. 

2003 - 2009 (including maternity leave and working part-time) PDRA Quaternary Quest (PI Elderfield PI), PACLIVA & Isaak Newton Trust (PI McCave) Department of Earth Sciences, University of Cambridge. This included syntheses of marine (benthic foraminifera stable isotopes and sedimentary carbonate) and terrestrial (pollen) data, to contribute to understanding of regulation of atmospheric CO2 on glacial-interglacial timescales and its coupling to climate change (QQ). Furthermore, I developed of time series data on deep-water current strength in order to assess overflow variability and vigour of thermohaline circulation in the North Atlantic during the Holocene and Marine Isotope Stage 3 on decadal to millennium time scales.

Professor in Paleoceanography and Biogeochemistry

My expertise is in palaeoenvironmental and palaeoclimatic reconstruction of marine environments. This includes rapid  and long-term climate change and related environmental changes. For the past 15 years my research has focused on expanding our understanding of the sea-water oxygen and carbon cycles, through the development and advancement of novel proxy methods, and application of these methods to reconstruct oxygen levels and carbon cycling through time. This research is instrumental in understanding ocean and atmospheric carbon cycling. 

I currently have funding through a Future Leaders Fellowship, which focusses on the development and application of proxy methods to reconstruct oxygen concentrations of seawater during warm periods in the geological past.

Since the 1960s the oceans have lost ~2% of their oxygen, a trend expected to accelerate in relation with global warming. Future deoxygenation, along with overfishing, threatens the sustainability of economically important fisheries and marine ecosystems and will impact global biogeochemical cycles (carbon, nitrogen). However, predictions of the future are hampered by a poor understanding of the longer-term natural oxygen cycle. By reconstructing oxygen concentrations in the past, using novel methods, we are extending our knowledge of the longer term oxygen cycle, and help improve predictions of future oxygen level changes.

The material we use to develop proxy methods and past time-series involves deep sea sediments. Not only do we use the bulk sediments, we also study some fossils that are preserved within them: the shells of microorganisms called foraminifera. Some foraminifera species float near the ocean surface, called planktonic foraminifera, and can be used to assess the presence of subsurface oxygen minimum zones, seawater temperatures, etc. Species that live on or in sediments at the bottom of the ocean are termed benthic foraminifera and can be used to reconstruct bottom water oxygen concentrations and ventilation.

My group are working with sediments from the International Ocean Discovery Program to determine if there have been changes dissolved oxygen contents, currently focussing on the Pacific Ocean, which represents the most poorly oxygenated ocean basin. 

Research research highlights:

Nilsson-Kerr et al. (2025, EPSL): provides new data and a synthesis of existing data to assess the long-term oxygenation of the Pacific Ocean following the closure of the Central American Seaway, suggesting there was a multi-stage closure that affected the oxygenation of different water depths.

Khon et al. (2021, Geophysical Research Letters): provides model simulations (Kiel Climate Model and PISCIS) of open and closed Central American Seaway, and indicates that the Pacific Ocean was better oxygenated when the seaway was open.