Interactions between arsenic species and marine algae
The arsenic concentration and speciation of marine algae varies widely, from 0.4 to 23 ng.mg/sup -1/, with significant differences in both total arsenic content and arsenic speciation occurring between algal classes. The Phaeophyceae contain more arsenic than other algal classes, and a greater proportion of the arsenic is organic. The concentration of inorganic arsenic is fairly constant in macro-algae, and may indicate a maximum level, with the excess being reduced and methylated. Phytoplankton take up As(V) readily, and incorporate a small percentage of it into the cell. The majority of the As(V) is reduced, methylated, and released to the surrounding media. The arsenic speciation in phytoplankton and Valonia also changes when As(V) is added to cultures. Arsenate and phosphate compete for uptake by algal cells. Arsenate inhibits primary production at concentrations as low as 5 ..mu..g.1/sup -1/ when the phosphate concentration is low. The inhibition is competitive. A phosphate enrichment of > 0.3 ..mu..M alleviates this inhibition; however, the As(V) stress causes an increase in the cell's phosphorus requirement. Arsenite is also toxic to phytoplankton at similar concentrations. Methylated arsenic species did not affect cell productivity, even at concentrations of 25 ..mu..g.1/sup -1/. Thus, the methylation of As(V) by the cell produces a stable, non-reactive compound which is nontoxic. The uptake and subsequent reduction and methylation of As(V) is a significant factor in determining the arsenic biogeochemistry of productive systems, and also the effect that the arsenic may have on algal productivity. Therefore, the role of marine algae in determining the arsenic speciation of marine systems cannot be ignored. (ERB)
- Research Organization:
- North Carolina Univ., Chapel Hill (USA)
- DOE Contract Number:
- EY-76-S-09-0890
- OSTI ID:
- 5875271
- Report Number(s):
- SRO-0890-T1
- Resource Relation:
- Other Information: Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
59 BASIC BIOLOGICAL SCIENCES
ALGAE
PRODUCTIVITY
ARSENIC
BIOGEOCHEMISTRY
METABOLISM
TOXICITY
PHYTOPLANKTON
WATER POLLUTION
AQUATIC ECOSYSTEMS
BIOLOGICAL ACCUMULATION
EXPERIMENTAL DATA
ISOLATED VALUES
METHYLATION
REDUCTION
SEAWATER
AQUATIC ORGANISMS
CHEMICAL REACTIONS
CHEMISTRY
DATA
DATA FORMS
ECOSYSTEMS
ELEMENTS
GEOCHEMISTRY
HYDROGEN COMPOUNDS
INFORMATION
NUMERICAL DATA
OXYGEN COMPOUNDS
PLANKTON
PLANTS
POLLUTION
SEMIMETALS
WATER
560302* - Chemicals Metabolism & Toxicology- Microorganisms- (-1987)
520200 - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)
550700 - Microbiology
550200 - Biochemistry