Organic Isotope Geochemistry

Organic Isotope Geochemistry

Group of Dr. Alfredo Martínez-Gracía

The Organic Isotope Geochemistry group studies the evolution of the Earth system including its physical, chemical and biological components. We combine the study of modern processes with the analysis of past climatic and environmental archives such as marine and lake sediment sequences, deep and shallow water scleractinian corals, speleothems, tooth enamel and ice cores using a variety of geochemical techniques, including organic biomarkers, and stable isotopes of Hydrogen, Carbon, Nitrogen and Oxygen.

Organic matter preserved through the geological record represents a vast repository of information about past changes in Earth’s biogeochemical cycles and climate. We investigate the distribution and isotopic composition of key organic molecules synthetized by aquatic and terrestrial organisms (biomarkers) that can provide insights on the variability of a wide variety of environmental processes in the past (e.g. ocean and lake temperatures, phytoplankton productivity, regional rainfall, ecosystem structure, or atmospheric CO2 levels).

In addition, over the past years we have pioneered (together with Daniel Sigman’s lab at Princeton University) the application of a new analytical technique that allows high precision measurements of the nitrogen isotopic composition of the trace amounts of organic matter protected from alteration within the mineral structure of different fossil types (e.g. foraminifera, corals, diatoms or tooth enamel). This approach has offered a new window to study changes in key components of the marine N cycle across a wide range of timescales including: seasonal changes during the Anthropocene, millennial-scale changes across the glacial/interglacial cycles of the Plio-Pleistocene, and also long-term changes through the Cenozoic era.

Go to Editor View