Climate Change and Earth-Ocean-Atmosphere Systems
Past climate changes, paleoceanography and biomineralization.
My general research interests cover a broad spectrum of the Earth Sciences with particular emphasis on past climate changes, paleoceanography and biomineralization.
Developing a proxy for reconstructing past ocean seasonality using foraminiferal geochemistry. The amplitude of seasonal and inter-annual changes in seawater temperature and salinity is one of the major characteristics of the coupled ocean-climate system. Reconstructing these crucial oceanographic parameters is of high priority but remains mostly unachieved.
My colleagues and I study the natural variability in geochemical signals of modern and fossil planktonic foraminiferal populations using various microanalytical techniques such as secondary ion mass spectrometry (SIMS) and laser ablation mass spectrometry. We aim to accurately quantify the biological component within Mg/Ca variability using top quality sediment trap samples (fossil population) with bi-weekly resolution and also core-top samples (modern population) collected directly below the sediment trap.
Paleoceanography of the Tropical Pacific its relationship with ENSO system. In the modern climate system, the El Niño Southern Oscillation (ENSO) is the second largest source of climate variability after the solar cycle. Its 2-7 year oscillations from positive (El Niño) to negative (La Niña) phases leads to a large redistribution of heat and moisture fluxes across the planet resulting in severe social and economic impacts. Understanding its response to increased concentrations of greenhouse gases is crucial for predicting future climate and its social and economic impacts. Effective modelling or testing of predictions in this area using current global circulation climate models is hampered by the absence of a long time observational record from the Tropical Pacific. My colleagues and I investigate the link between Tropical Pacific paleoceanography and past climate changes during the last 25kyr. We use the geochemistry of planktonic foraminifera to reconstruct the mean state of the Tropical Pacific (the long term average distribution of oceanographic and atmosphere parameters across the Equatorial Pacific) and ENSO variability. Results of this work provide a unique insight into the evolution of the ENSO system during the last 25 kyr and its significant influence on global climate changes.
Mg/Ca variability across a single shell of Orbulina universa (map created using NanoSIMs microanalysis)