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High plankton densities reduce mercury biomagnification
1Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA. celia.chen@dartmouth.edu
Environmental Science & Technology
|January 26, 2005
Summary
Higher plankton density in lakes is linked to lower mercury (Hg) accumulation in aquatic life. This finding suggests plankton density can predict mercury biomagnification in fish.
Area of Science:
- Environmental Chemistry
- Ecology
- Aquatic Toxicology
Background:
- Mercury (Hg) contamination in aquatic ecosystems is a significant environmental concern.
- Understanding factors influencing mercury bioaccumulation and biomagnification is crucial for risk assessment.
Purpose of the Study:
- To test the hypothesis that plankton densities influence mercury accumulation in biota.
- To identify plankton density as a potential predictor of mercury biomagnification in lakes.
Main Methods:
- Field sampling of phytoplankton, zooplankton, and fish across 20 lakes in the northeastern United States.
- Measurement of total mercury (Hg) concentrations and plankton densities.
- Statistical analysis of Hg burdens and plankton densities in 38 additional lakes.
Main Results:
- Phytoplankton density showed a negative correlation with Hg concentrations in phytoplankton and small zooplankton.
- Zooplankton density was negatively correlated with Hg in zooplankton, herbivorous fish, and predatory fish.
- Zooplankton density alone explained over 40% of the variation in predatory fish Hg levels.
Conclusions:
- Plankton density is a significant factor influencing mercury levels in aquatic organisms.
- Lower plankton densities are associated with higher mercury concentrations at lower trophic levels.
- Plankton density can serve as a cost-effective predictor for mercury biomagnification potential in lakes.