Freshwater diatoms in the Sajama, Quelccaya, and Coropuna glaciers of the South American Andes

Abstract

Diatoms in ice cores have been used to infer regional and global climatic events. These archives offer high-resolution records of past climate events, often providing annual resolution of environmental variability during the Late Holocene. Recently, the first low-latitude tropical diatoms were described from the Quelccaya Summit Dome. Here, we document diatoms observed in ice cores from Quelccaya, spanning AD 1300 to 1815, along with those from two additional glaciers (Coropuna, and Sajama glaciers) in the tropical Andes, spanning AD 1764 to 1814. Diatom assemblages recovered from these three sites were rare, but differ in abundance and species composition through time. Assemblages are characterized by cosmopolitan and aerophilic species, mostly pennate diatoms. There were 44 taxa in all, with Pinnularia cf. borealis Ehrenberg being the most common species encountered in the samples. Eleven taxa were found at all three sites. Both Coropuna and Sajama had taxa that were unique to these locations, whereas Quelccaya had no unique taxa. Due to the rarity of diatoms and the cosmopolitan nature of the dominant species, it is not possible to determine their origin, limiting their utility in paleoclimate reconstructions.

Keywords:

• ice cores
• tropical Andes
• aerophilic diatoms
• bacillariophyceae
• Pinnularia borealis Ehrenberg
• dust transport

Acknowledgements

We thank two anonymous reviewers for their comments which strengthened our manuscript. We also thank Dr LuAnn Wandsnider, Dr David Harwood, Dr David Watkins, and Ms Brandi Moore for providing feedback on early drafts of the manuscript.

Disclosure statement

The authors have received no financial interest or benefit from the direct applications of this research.

ORCID

D. Marie Weide http://orcid.org/0000-0001-9456-9457

Additional information

Funding

This work was funded in part by financial assistance from a National Science Foundation Integrative Graduate Education and Research Traineeship grant to SF and colleagues, as well as NSF grants EAR-1251678 and EAR-1338694 to SF.