Efficacy of sonication-assisted sieving on Quaternary pollen samples

ABSTRACT

Debris in archaeological pollen samples can obscure pollen grains during microscopic analysis. When attempting to remove debris smaller than 10 microns from a pollen sample, screen openings can be too small, requiring the sample to be agitated in order to facilitate its passing through the screen. We recently developed a new method that uses a Branson^© S450 sonicating disruptor horn to agitate the sample, keeping the screen free from debris. Using this method, we have been successful in ridding the pollen sample of debris smaller than 10 microns. This paper presents the results of an investigation of the potential effects of sonication on pollen preservation. We selected 12 fresh pollen types based on a unique range of morphological characteristics, and subjected this assemblage to sonication for different lengths of time and at variable output intensities. Our study demonstrated that when used for 3 minutes at low to medium output intensities, a sonicating disruptor horn can aid in the removal of unwanted debris without considerably damaging pollen grains. We also did not find evidence that pollen colliding with other debris in a sample increased levels of degradation. Analysis on the efficacy of sonication-assisted sieving demonstrated that more tiny debris was removed from the sample at higher frequencies and over increasing durations.

KEYWORDS:

• Sonication
• pollen preservation
• palynological methods

Acknowledgments

Thank you to the Palynology Research Laboratory and the Department of Anthropology at Texas A&M University for providing the facilities to complete the experiments. Thank you to David Carlson and Crystal Dozier for providing input on the organization and presentation of the data. We appreciate the input of Cortland Eble and an anonymous reviewer, whose comments improved this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Angelina G. Perrotti

ANGELINA G. PERROTTI is a PhD candidate in the Department of Anthropology at Texas A&M University. Current research interests include Terminal Pleistocene environments of North America, the use of coprophilous fungi as megaherbivore indicators and the peopling of the Americas.

Taylor Siskind

TAYLOR SISKIND is a senior anthropology major at Texas A&M University. To combine her journalism minor with her interest in the earth's environment, she is currently interning at the magazine Natural History.

Mary Katherine Bryant

MARY KATHERINE BRYANT is currently an undergraduate at Texas A&M University majoring in anthropology with a focus on archaeology. She is currently part of the GUMP mentoring program engaging research with an interest in the use of pollen in archaeology.

Vaughn M. Bryant

VAUGHN M. BRYANT received degrees from the University of Texas at Austin (BA in geography, MA in anthropology, PhD in botany) and currently teaches at Texas A&M University in College Station, Texas. He is a professor of anthropology and the Director of the Texas A&M University Palynology Laboratory. He is also an adjunct professor of forensic sciences at the University of Nebraska. He is a former editor of Palynology and former president of AASP. Currently he is a Trustee and the Secretary of the AASP Foundation.