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Quantitative centrifugation to extract benthic protozoa from freshwater sediments
M Starink1, M J Bär-Gilissen, R P Bak
1Centre for Limnology, Netherlands Institute of Ecology, 3631 AC Nieuwersluis, The Netherlands.
Applied and Environmental Microbiology
|January 1, 1994
Summary
Two centrifugation methods efficiently extract freshwater protists from sediments. Isopycnic centrifugation yields high recovery from sandy and gyttja-like soils, while rate zonal centrifugation is suitable for organic-rich litter sediments.
Area of Science:
- Aquatic Ecology
- Microbiology
- Protistology
Background:
- Freshwater sediments harbor diverse protist communities.
- Efficient extraction methods are crucial for studying protist ecology.
Purpose of the Study:
- To describe and compare two novel centrifugation techniques for protist extraction from various freshwater sediments.
- To evaluate the recovery rates of protists using these methods.
Main Methods:
- Adapted isopycnic centrifugation for sandy and gyttja-like sediments.
- Rate zonal centrifugation for organic-rich, litter-like sediments.
- Comparison of recovery efficiency using different densities and centrifugation parameters.
Main Results:
- Isopycnic centrifugation showed 100% recovery in sandy sediments and up to 94% in gyttja-like sediments.
- No significant protist loss observed with sodium diatrizoate and Percoll.
- Recovery from litter-like sediments is dependent on centrifugation force, time, and cell dimensions.
Conclusions:
- Both described centrifugation methods are effective for freshwater protist extraction.
- A predictive model for recovery from litter-like sediments was developed based on cell and centrifugation characteristics.