Marine phytoplankton toxic effects

Harmful algal blooms Proliferation of phytoplankton that have toxic effects on other marine organisms and humans. The harmful effects include, but are not limited to, poisoning from biotoxins and mechanical abrasion. 

Interactions of trace elements with algae in the marine environment are being extensively studied (1-3, 5-12). Copper and zinc, both essential micronutrients required by phytoplankton, may be toxic at elevated concentrations (11-13). The biological effects of copper and zinc are strongly dependent on their speciation the activity of the free metal ion has been shown to be a key parameter (13). Toxic effects of Cu on marine algae have been observed in the range of pCu 10-12 (11-13). 

B Sundstrom, L Edler, E Graneli. The global distribution of harmful effects of phytoplankton. In E Graneli, B Sundstrom, L Edler and DM Anderson, eds. Toxic Marine Phytoplankton. Amsterdam Elsevier, 1990, pp. 537-541. 

Alexander, V. (1977). Preliminary results of studies on toxicity and effects of petroleum hydrocarbons and marine phytoplankton In Wolf, D. (ed). Symposium of fate and effects of petroleum hydrocarbons in marine ecosystem and organisms, pergamon Press. New York. 646p. 

From the human perspective, HABs are problematic because they cause (1) risks to human health, (2) loss of natural or cultured seafood resources, (3) impairment of tourism and recreational activities, and (4) damage to noncommercial marine resources and wildlife. Exposure pathways include (1) consumption of toxic shellfish that have accumulated phytoplankton toxins filtered from the water, (2) consumption of tropical fish that have accumulated phytoplankton toxins (ciguatera), (3) inhalation of aerosolized toxins ejected from the sea surface, and (4) skin contact resulting in irritations due to allergy-like reactions. Harmful health effects from acute exposures have been relatively well studied. Less well known are the health effects resulting from chronic exposures to low toxin levels. This is of particular concern with regards to marine mammals and seabirds. 

In Japan, more than half of agricultural land is paddy fields. The rice herbicides are easy to run off especially because those are applied directly to the surface water of the paddy field. Thus, some rice herbicides are detected frequently in river water of Japan at die low ppb levels for some mondis after the rice-planting period (2-6). Alterations of a phytoplankton community as a result of toxic stress may affect the structure and ftmctioning of the whole ecosystem (7). However, there have been few reports on the influence of the rice herbicides to phytoplankton (8-11). Therefore it is inqiortant to assess the effects of these herbicides on primary production in riverine, lake and marine ecosystems. 

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