Antarctic mixotrophic protist abundances by microscopy and molecular methods
Rebecca J Gast1, Zaid M McKie-Krisberg, Scott A Fay
1Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
FEMS Microbiology Ecology
|April 3, 2014
Summary
Researchers developed a new qPCR method to study mixotrophic protists in Antarctic waters. This method helps understand their distribution and impact on marine food webs, revealing seasonal influences and key environmental factors.
Area of Science:
- Marine microbial ecology
- Protistology
- Antarctic oceanography
Background:
- Mixotrophic protists, combining photosynthesis and heterotrophy, significantly impact marine microbial food webs.
- Traditional methods for estimating mixotroph abundance lack species-level resolution.
- Understanding mixotroph distribution is crucial for marine ecosystem dynamics.
Purpose of the Study:
- To develop and apply SYBR-based quantitative PCR (qPCR) strategies for identifying and quantifying mixotrophic Antarctic algal species.
- To determine the total abundance of mixotrophs and specific species in Antarctic water samples.
- To identify environmental variables influencing the distribution and abundance of these mixotrophic species.
Main Methods:
- Development of SYBR-based qPCR assays for three Antarctic mixotrophic algal species.
- Application of qPCR alongside traditional ingestion experiments for abundance estimation.
- Statistical analysis to correlate mixotroph abundance with environmental variables (temperature, oxygen, season, etc.).
Main Results:
- Mixotroph distribution in Antarctic waters was strongly influenced by season.
- Temperature, oxygen, date, fluorescence, conductivity, and latitude were key environmental factors affecting species abundance.
- Phosphate became significant when nutrient data was included, and one species, Pyramimonas, dominated grazing in a specific sample.
Conclusions:
- The developed qPCR method provides a robust tool for quantifying mixotrophic protists in environmental samples.
- Seasonal dynamics and specific environmental factors significantly shape the distribution and abundance of Antarctic mixotrophs.
- Mixotrophic protists, particularly certain species like Pyramimonas, can exert substantial control over bacterial populations in Antarctic marine ecosystems.
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