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Quantification of Heavy Metals and Other Inorganic Contaminants on the Productivity of Microalgae
Published on: July 10, 2015
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Mercury Accumulation Pathways in a Model Marine Microalgae: Sorption, Uptake, and Partition Kinetics
Isabel Garcia-Arevalo1, Jean-Baptiste Bérard2, Johannes Bieser3
1IFREMER, CCEM Contamination Chimique des Écosystèmes Marins, F-44300 Nantes, France.
ACS ES&T Water
|July 18, 2024
Summary
Phytoplankton accumulate mercury (Hg) through sorption and internalization, with the phycosphere acting as a key intermediate step. A new model quantifies Hg transfer, aiding aquatic food web mercury uptake predictions.
Area of Science:
- Environmental Science
- Marine Biology
- Biogeochemistry
Background:
- Phytoplankton are primary producers in aquatic ecosystems.
- Mercury (Hg) bioaccumulation in phytoplankton is a critical step in aquatic food chain biomagnification.
- Cellular mechanisms of mercury uptake by phytoplankton are not fully understood.
Purpose of the Study:
- To investigate the interactions of marine phytoplankton with dissolved inorganic divalent mercury (iHg) and monomethyl mercury (MMHg).
- To develop and validate a model for mercury cellular accumulation in marine phytoplankton.
Main Methods:
- Examined mercury sorption and internalization in the marine haptophyte *Tisochrysis lutea* at picomolar concentrations.
- Quantified mercury partition coefficients, sorption, uptake, and release rates.
- Developed a time-dependent, three-compartment model (exposure medium, phycosphere, internalized mercury) using pseudo-first-order kinetics.
Main Results:
- Observed successive sorption and internalization of both iHg and MMHg by *Tisochrysis lutea*.
- Quantified transfer rates of mercury between the exposure medium, phycosphere, and internalized cellular compartments.
- The phycosphere was identified as an intermediate compartment facilitating mercury accumulation.
Conclusions:
- The developed three-compartment model accurately describes mercury cellular accumulation in phytoplankton.
- The model's successful application to literature data demonstrates its robustness for predicting mercury uptake in marine food webs.
- Provides crucial insights into the role of the phycosphere in mercury biogeochemical cycling.
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