Modified Rapid Phytolith Methods
Kali R Wade
Abstract
Processing procedures here are modified from those outlined in Katz et al 2010. Samples can be processed in this way and, following completion, rinsed with deionized water and dried to a stable state for storage and to make extra slides for morphological IDs.
Before start
Follow the "fail-safe" practices outlined here, in addition to any other health and safety paperwork or contamination recommendations from your organization.
Steps
Fail-Safe Practices
Wiping down all equipment, surfaces, and tools used with soap and water followed by acetone (beginning and end of every day of the project).
Checking and adjusting the density of sodium polytungstate (SPT) to conform to the protocol being used (normally between 2.3 and 2.5 g/ml).
Plating one slide of each hydrocloric acid (HCl) SPT, and the mounting agent (likely Cargille Immersion Oil, Type B) and viewing them under microscopy to ensure no contamination.
Calibrating analytical balances.
Sample Preparation
If necessary, place samples in desiccator overnight, set to 30°C.
Label 1.5 ml centrifuge tubes (2 per sample being processed) with sample ID.
Sieve samples through 0.5 mm mesh, rinsing mesh between each sample with soap and water, acetone, then deionized water.
Weigh 30-80 mg of sediment into 1.5 ml centrifuge tube. Ensure balance is tared following the weight of the tube, prior to weighing sediment, with balances' scale and lab doors closed.
Organic and Carbonate Removal
Add 50μl of 6N HCl, waiting for bubbling to cease (give the samples a few minutes). Shake tube to ensure chemical gets through all of the sample
Add 450μl of 2.5 g/ml SPT
Breaking up Soil Aggregates & Creating Pellet
Vortex for 3 sec, sonicate for 10 min, vortex 3 sec
Centrifuge for 10 min at 6rpm
Plating Slides
Remove supernatant to clean 1.5ml test tube. Be mindful of proper labels.
Vortex supernatant for 3sec
Pipette 50μl of supernatant onto a labelled microscope slide and cover with a coverslip. Seal with nail polish. Slides last between 6-12 hours before crystallization
Inventory samples.
