Plant lipids as proxies to trace the origin and dynamics of soil organic carbon

Lipids from the wax layers of plant leaves and plant roots as preserved in soils and sediments have been used for decades as proxies for environmental reconstructions. In particular the n-alkanes of higher chain-lengths (ca. C₂₅-C₃₇) are used to this end. The past decade has seen an increased research attention for the use of plant lipids as molecular proxies. This includes an emerging interest in applications aimed at unravelling the dynamics of soil organic matter (SOM) rather than answering purely palaeo-ecological questions^[1] as well as in reconstructing multiple environmental factors at once. Here I highlight these developments via two examples of recent work by our group. In the first example we applied analysis of n-alkanes and n-alcohols preserved in plaggic Anthrosols to reconstruct the origin of the plant material that was used as the stable fillings that were applied to fertilize the soils in this unique agricultural system. In the second example we examined plant derived n-alkanes preserved in soils along an altitudinal transect in the Ecuadorian Andes as part of a coupled reconstruction of palaeo-vegetation and palaeo-climate. I discuss both the exciting new insights gained as well as the challenges that still remain.

References

[1] J.M. van Mourik, T.V., Wagner, J.G. de Boer, B. Jansen, (2016). The added value of biomarker analysis to the genesis of plaggic Anthrosols; the identification of stable fillings used for the production of plaggic manure. SOIL, 2, 299-310

[2] B. Jansen, H. Hooghiemstra, S.P.C. de Goede, J.M. van Mourik, (2019). Chapter 5 - Biomarker analysis of soil archives, Eds. J.M. van Mourik, J.J.M. Van der Meer, Developments in Quaternary Sciences, 18: 163-222

[3] M.L. Teunissen van Manen, B. Jansen, F. Cuesta, S. León-Yánez, S., W.D. Gosling, (2020). From leaf to soil: n-alkane signal preservation, despite degradation along an environmental gradient in the tropical Andes. Biogeosciences, 17, 5465-5487