elemental analyzer (EA) Isotope Ratio Mass Spectrometry was used to measure ∂13C values on soil organic matter from reservoirs and depressions at the ancient Maya urban centers of Tikal, Guatemala and Yaxnohcah, Mexico. Variation in δ13C values on soil organic matter were > −2.0‰, which suggests enrichment from C4 plants including maize, other tropical grasses (Poaceae), and tropical sedges (Cyperaceae), CAM plants (Clusia sp.), and cyanobacteria (blue-green algae). Cyanobacteria were likely a major contributor to the 13C enrichment of soil organic matter in Maya reservoirs and depressions, which has obfuscated our understanding of ancient Maya maize production. It is possible that the Maya used cyanobacteria as a fertilizer, which enriched agricultural field soil organic matter.
Bibliographical noteFunding Information:
The U.S. National Science Foundation (BCS-0810118 [D.L.L., N.P.D], BCS-1632392 [N.P.D.,D.L.L.]; and BCS-1642547 [D.L.L., N.P.D., T.L.H.]), the Wenner-Gren Foundation (7799 [D.L.L., N.P.D.]), the Alphawood Foundation (V.L.S.) the University of Cincinnati Intellectual Property Fund (A.A.W.), the Charles Phelps Taft Foundation (K.B.T.), the Social Sciences and Humanities Research Council of Canada, Grants 430-2017-00190 and 892-2019-3070, with ongoing financial support from the University of Calgary, the Universidad Autónoma de Campeche, and the University of Cincinnati. We also thank Jerry Murdock and Venture Capital Partners for their significant contributions to the lidar reconnaissance. We also thank Dr Annette Rowe for advice and access to her lab equipment. The Tikal project was conducted in accordance with all laws and regulations of Guatemala with permits granted to project co-directors David Lentz and Liwy Grazioso by the Ministerio de Cultura y Deportes, the Dirección General del Patrimonio Cultural y Natural, the Instituto de Antropología e Historia and the Departamento de Monumentos Prehispanicos y Coloniales (Convenio Numero 6-2009). Plant specimens and soil samples were transported into the United States under the auspices of permits awarded by the US Department of Agriculture to David Lentz (#PDEP-09-00052) and Nicholas Dunning (#S-69494), respectively. We are especially grateful to the editor and anonymous reviewers who greatly improved the manuscript. All regulations proscribed in the CITES treaty and other international agreements were complied with in full. Site reports and other basic data from the Tikal and Yaxnohcah projects are available online through the following links: ( http://www.mesoweb.com/es/informes/PSMAT-Lentz_et_al_2011.pdf ); and https://www.mesoweb.com/resources/informes/Yaxnohcah2016.html .
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the University of Cincinnati Intellectual Property Fund, Charles Phelps Taft Foundation, The U.S. National Science Foundation, Alphawood Foundation, Social Sciences and Humanities Research Council of Canada, (grant numbers BCS-0810118, BCS-1632392, and BCS-1642547, 430-2017-00190 and 892-2019-3070).
© The Author(s) 2022.
- Zea mays (maize)
- δ13C enrichment