EGU2020-10897, updated on 21 Jun 2023
https://doi.org/10.5194/egusphere-egu2020-10897
EGU General Assembly 2020
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A 500-year record of paleoclimate and paleoenvironment from the Lacandon Forest, southern Mexico

Karla Zurisadai Rubio Sandoval1, Alexander Correa-Metrio2, Juan Felipe Franco-Gaviria3, Antje Schwalb4, Philipp Hoelzmann5, Mark Brenner6, Maarten Blaauw7, William Kenney6, Jason Curtis6, and Liseth Pérez4
Karla Zurisadai Rubio Sandoval et al.
  • 1Bremen University, MARUM, Geosciences , Germany (krubiosandoval@marum.de)
  • 2Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad de México, México.
  • 3Department of Geography, University of Exeter, Exeter, United Kingdom.
  • 4Institut für Geosysteme und Bioindikation, Technische Universität Braunschweig, Braunschweig, Germany.
  • 5Institut für Geographische Wissenschaften, Physische Geographie, Freie Universität Berlin, Berlin, Germany.
  • 6Department of Geological Sciences and Land Use and Environmental Change Institute (LUECI), University of Florida, USA.
  • 7School of Natural and Built Environment, Queen's University Belfast, United Kingdom.

Tropical karst Lakes Metzabok (550 masl, surface area = ~77 ha, zmax = 25 m) and Nahá (832 masl, surface area = ~57 ha, zmax = 36 m) are located in the Lacandon Forest, in the state of Chiapas, southern Mexico. The region is characterized by high aquatic and terrestrial biodiversity. We generated high-resolution paleoclimate and paleoenvironmental records that span the last ~500 years, using invertebrate remains (ostracodes and gastropods) and geochemical variables (elemental and mineralogical contents) in sediment cores from the two water bodies. We collected a short sediment core from each lake (Metzabok = 46 cm, Nahá = 60 cm) and analyses were carried out at 1-cm intervals. Uppermost sediments in the cores were dated using 210Pb and 137Cs, and deeper deposits were dated by 14C. Ostracodes and snails were identified to species level and their abundances were quantified. Concentrations of Ti and Fe were determined by portable XRF. The geochemical record reveals information about past climate variability, human-mediated erosion and transport of terrigenous elements. Changes in ostracode and gastropod assemblages mainly reflect past lake level fluctuations and changes in water conductivity. The dominant ostracode species was Cytheridella ilosvayi and the most common gastropod is Aroapyrgus sp., indicative of water depths ≤40 m and low water conductivity, respectively. Analysis of the ecological distances between samples suggests that Lake Metzabok is unstable, with frequent ecological changes equal to or greater than 50% of the community. These changes may have resulted from dramatic environmental differences associated with hydrological dynamics during dry and rainy seasons. The Nahá record presents two environmental conditions, i.e. periods of high stability and periods of change, when the system was in transition from a dry period to a wetter one, or vice versa. Despite differences between the two lakes with respect to elevation, size, depth, and seasonal dynamics, both records contain evidence of droughts ca. 300 and 200 yr BP, during the Little Ice Age. Whereas both records show a long-term tendency towards higher moisture conditions, the high-resolution of our study enabled us to detect fluctuations between dry and wet periods over the last 500 years that previous studies failed to recognize.

How to cite: Rubio Sandoval, K. Z., Correa-Metrio, A., Franco-Gaviria, J. F., Schwalb, A., Hoelzmann, P., Brenner, M., Blaauw, M., Kenney, W., Curtis, J., and Pérez, L.: A 500-year record of paleoclimate and paleoenvironment from the Lacandon Forest, southern Mexico , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10897, https://doi.org/10.5194/egusphere-egu2020-10897, 2020.

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