Dr. Thomas Larsen
I am interested in understanding how changes in resource availability and biogeochemical cycling disrupt ecosystem structure and the communities inhabiting it. My goal is creating benchmarks of resource availability by comparing past and current disturbance regimes, and to reference conditions prior and during the Anthropocene. These benchmarks are important for forecasting how ecosystems will equilibrate to anthropogenic changes, device strategies for sustainable use of natural resources and mitigate adverse effects of global change. The pervasiveness, magnitude, and variety of human impacts leave little doubt we have entered a distinct era from an environmental viewpoint. While geologists may be concerned about the detectability of the Anthropocene in future geological records, this consideration is in my opinion not relevant for (paleo)ecological research as humans have modified ecosystems ever since we accelerated megafauna extinctions during the Pleistocene. Hence, a key component of my research is characterizing nonstationary environments and relate these changes to how humans currently use and have used resources in the past.
To create benchmarks of past and current ecosystems, my research has a strong methodological component. Notably, I am one of the lead developer of a method termed stable isotope fingerprinting of amino acids that can overcome many of the challenges of reconstructing diets and nutrition with prevailing tracer methods. These carbon stable isotope patterns can trace the biosynthetic origins of proteinogenic amino acids to algae, bacteria, fungi and plants. The method is also showing great promise of categorizing taxa within these phylogenic groups and resolving dietary niches of consumers. They are particularly well suited for deep investigation of diets and primary producers across time and space because the fingerprints remain largely invariant across different environmental conditions. Recent research also shows that the amino acid isotope patterns can inform about the relative composition of dietary macronutrients. I also use nitrogen stable isotope ratios of amino acids to infer the trophic positions of consumers. As the research leader of the Biochemistry Group here at SHH, I take a keen interest in other biomolecular techniques to understand natural ecosystems and past lifeways such as reconstructing animal domestication, human demographics, dairying, and documenting how plants were used in the past for their scents and psychoactive properties. To that end, we identify and characterize dietary lipids, fecal steroids, and a suite of secondary metabolites from ancient sediments and artefacts.
I received my M.Sc. in Biology at Department of Zoology, Aarhus University and my Ph.D. in Ecology at Faculty of Life Sciences, University of Copenhagen. I have held research positions in various countries and institutions: University of Alaska Fairbanks, University of California Santa Cruz, University of Aarhus, CEAB-CSIC Spain and University of Kiel. I am currently the Research leader of the Biochemistry Group at Department of Archaeology, where I am leading the department's effort in applying biomolecular methods to archaeology.
I am mostly known for a dietary tracer method termed isotope fingerprinting of amino acids. Together with professor Diane O'Brien at UAF, I pioneered this method for identifying the biosynthetic origins of proteinogenic amino acids. The fingerprints remain invariant across different environmental conditions, and they can characterize food web linkages across various systems and in some instances identify geographical origins of aquatic resources. The isotope fingerprints have also shown great promise for food authentication and for reconstruction of past human diets from material records.
Please see my Research Gate profile.
- I am a co-lead investigator of a UK-German funded research project (2018-2020, EUR 750,000, NERC / BMBF) that examines the competitive interactions and foraging ecology between two closely related species of seabirds in the North Atlantic. We use a mix of location trackers and isotope biomarkers to investigate how northward shift in lipid-rich forage fish create ecosystem-wide cascade effects.
- Co-investigator of the project “Production of high quality fish feed from enchytraeid biomass” led by Martin Holmstrup (2018-2021, DKK 2,360,313, The Danish Council for Independent Research, Technology and Production Sciences).
- Co-investigator of the project “Carbon sequestration by Greenland’s marine forests in a warming Arctic (CARMA)” led by Dorte Krause-Jensen (2018-2021, DKK 2,300,704, The Danish Council for Independent Research, Technology and Production Sciences).