Aquatic systems mollusks

Significant concentrations of cyanotoxins have been found to accumulate in the tissues of macroinvertebrates such as mollusks and crustaceans, presenting an indirect route of exposure for invertebrates, fish, and aquatic mammals at higher trophic levels (Negri and Jones 1995). In natural systems, mortality among benthic invertebrate herbivores is probably low because most bloom-forming bacteria are planktonic and only periodically come into contact with the benthos. Nevertheless, Kotak et al. (1996) determined that enhanced mortality of snails at the end of a bloom cycle in Canadian lakes was due to consumption of Microcystis cells that had formed a scum on the surface of macrophytes. Oberemm et al. (1999) found that aqueous microcystins, saxitoxins, and anatoxin-a all resulted in developmental delays in fish and salamander embryos. Interestingly, more severe malformations and enhanced mortality were observed when larvae were exposed to crude cyanobacterial extracts than to pure toxins applied at natural concentrations (Oberemm et al. 1999). 

Acrolein at a concentration of <500 ppm is also used to protect liquid fuels against microorganisms. The dialkyl acetals of acrolein are also usefiil in this application. In addition, the growth of algae, aquatic weeds, and mollusks in recirculating process water systems is also controlled by acrolein. 

A land-based pond system can exist exclusively for the cultivation of macroalgae or can be combined with other aquatic species such as finfish or mollusks. The combined approach, referred as integrated multitrophic aquaculture (IMTA), offers the opportunity to capitalize on the fact that wastes from the fish can act as a supply of nutrients for the algae while the algae can act as a source of feed for the fish. In this way IMTA functions as a miniature and synergistic ecosystem consisting of a variety of species that all have commercial values. ... 

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