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Updated: Jul 27, 2026
09:21
Sediment Core Sectioning and Extraction of Pore Waters under Anoxic Conditions
Published on: March 7, 2016
Freezing of sediments inappropriate for pore water selenium analysis
1Centre for Advanced Analytical Chemistry, CSIRO and Energy Technology, Private Mailbag 7, Bangor, NSW 2234, Australia.
Marine Pollution Bulletin
|September 3, 2004
Summary
Freezing sediment cores for selenium analysis is not recommended. Frozen samples showed up to 80x higher selenium concentrations due to cell rupture in selenium-accumulating bacteria.
Area of Science:
- Environmental Science
- Geochemistry
- Microbiology
Background:
- Sediment core analysis is crucial for understanding environmental processes.
- Accurate chemical analysis of pore water is essential for geochemical studies.
- Selenium is a key element in aquatic ecosystems, and its speciation is important.
Purpose of the Study:
- To evaluate the impact of freezing on selenium concentrations in sediment core pore water.
- To determine the suitability of freezing as a preservation method for selenium analysis in estuarine sediments.
Main Methods:
- Comparison of pore water selenium concentrations from frozen and chilled estuarine sediment cores.
- Experimental investigation into the cause of elevated selenium levels in frozen samples.
Main Results:
- Frozen sediment cores exhibited significantly higher pore water selenium concentrations compared to chilled cores (up to 80-fold increase).
- The observed increase in selenium is attributed to the lysis of selenium-accumulating bacteria upon freezing, releasing intracellular selenium.
Conclusions:
- Freezing sediment cores is an inappropriate method for preserving samples intended for selenium analysis.
- The integrity of microbial cells in sediment samples is critical for accurate selenium measurements, necessitating careful sample handling and preservation techniques.
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