Research
Research interests
I am interested in how variations in stable isotope ratios can be used as markers of environmental change and as tracers of energy and nutrient fluxes. I am currently involved in the following projects:
- Amino acid 13C fingerprints as a tool for characterizing marine and terrestrial derived carbon sources. Collaborators: Matthew McCarthy, Matthew Wooller, Diane O’Brien, Nils Andersen.
- Identifying changes in food web dynamics along a climate gradient in Northern Alaska. Collaborators: Marc Ventura, Diane O’Brien, Yiming Wang, Nils Andersen.
- Paleoenvironmental indicators: D/H isotope ratios in plant waxes extracted from ocean sediment cores. Yiming Wang, Nils Andersen, Ralph Schneider (PI).
Most of my current research is focused on a new amino acid fingerprinting method that I co-developed together with Diane O’Brien at Institute of Arctic Biology, Fairbanks. In a paper published in Ecology 2009 we show for the first time that different taxonomic lineages during biosynthesis generate unique carbon isotope patterns among the essential amino acids. Since these isotope fingerprints are based on natural occurring variations this new tool has the potential to track the food sources of animals that are otherwise intractable for studying foraging behavior.
Peer reviewed publications
- Larsen T, Taylor D, Leigh MB, O’Brien D (2009) Stable isotope fingerprinting: a novel method for identifying plant, fungal or bacterial origins of amino acids. Ecology 90: 3526-3535. [pdf][appendices]
Natural occurring isotope variations among seven essential amino acids are diagnostic of their biosynthetic origin
- Larsen T, Ventura M, Damgaard C, Hobbie E, Krogh PH (2009) Nutrient allocations and metabolism in two collembolans with contrasting reproduction and growth strategies. Functional Ecology 23: 745-755. [pdf][appendices]
Isotope turnover in adult Collembola
- Larsen T (2008) New record of the Keeled Skimmer (Orthetrum coerulescens) in Denmark. Entomologiske Meddelelser 76, 69-72. [pdf]
- O’Brien DM, Min K-J, Larsen T, Tatar M (2008) Use of stable isotopes to examine how dietary restriction extends Drosophila lifespan. Current Biology 18:R155-R156. [pdf][supplements]
- Larsen T, Luxhøi J, Magid J, Jensen LS, Krogh PH (2007) Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling. Biology and Fertility of Soils 44: 59-68. [pdf]
- Larsen T, Gorissen A, Krogh P H, Ventura M and Magid J (2007) Assimilation dynamics of soil carbon and nitrogen by wheat roots and Collembola. Plant and Soil 295:253-264. [pdf]
Source mixing triangle for Collembola with isotope additions
- Luxhøi J, Bruun S, Jensen L S, Magid J, Jensen A, Larsen T (2007) Modelling C and N mineralization during decomposition of anaerobically digested and composted municipal solid waste. Waste Management & Research 25: 170-176. [pdf]
- Demsar D, Dzeroski S, Larsen T, Struyf J, Axelsen JA, Bruus M, Krogh PH (2006) Using multi-objective classification to model communities of soil microarthropods. Ecological Modelling 191:131-143. [pdf]
- Larsen T, Axelsen J, Ravn HW (2004) Simplified and rapid method for extraction of ergosterol from natural samples and detection with quantitative and semi-quantitative methods using thin-layer chromatography. Journal of Chromatography A 1026:301-304. [pdf]
Quantification of ergosterol with TLC. Standards on the left and natural samples on the right.
- Larsen T, Schjønning P, Axelsen J (2004) The impact of soil compaction on euedaphic Collembola. Applied Soil Ecology 26:273-281. [pdf]
Collembola abundance and soil density
Sub Pages List
No Comments » Last modified on Feb 16th 2010
