Centro de Investigación y Control de la Calidad (CICC) · Centro Nacional de Alimentación (CNA); Laboratorio Nacional de Referencia de Biotoxinas Marinas. Actividades del Laboratorio Comunitario de Referencia de Biotoxinas Marinas. In : Avances y Tendencias en Fitoplancton Tóxino y Biotoxinas (ISBN. XIII Reunión Ibérica de Algas Tóxicas y biotoxinas marinas Vigo (Spain), th June CLIMATE CHANGE DRIVERS IMPACTS.
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Some algal species already produce toxins at low abundances of some hundreds of cells per litre, while other algal species must occur in some millions of cells per litre in order to cause any harm.
On the other hand, some species can bloom so densely, under exceptional conditions in sheltered bays, that they indiscriminately kill fish and invertebrates due to oxygen depletion. The symptoms included abdominal cramps, vomiting, disorientation and memory loss amnesia.
These PSP toxins are accumulated by shellfish grazing on algae producing these toxins. These toxins are secondary metabolites with no explicit role buotoxinas the internal economy of the organisms that produce them and with very specific activities in mammals.
In this way the survival of mxrinas dinoflagellates from one season to the other season is assured Mons et al.
Fast-growing algae quickly strip away nutrients in the upper layer, leaving nitrogen and phosphorus only below the interface of the layers, called the pycnocline. It is not clear why some micro-algal species produce toxins. Some species produce basically harmless water discolorations.
This diatom was consumed by anchovies that in turn were eaten by the birds. DSP incidences, or at least the presence of DSP toxins, appear to be increasing and DSP toxins producing algae and toxic bivalves are frequently reported from new areas.
The most affected areas seem to be Europe and Japan. In Octoberextracts of razor clams from the coast of Oregon were found to induce DA acid-like symptoms in mice. They are probably used by their producers as a way to compete for space, fight predation or as a defence against the overgrowth of other organisms Botana et al. Mid-water exchange in regional seas may reduce the risk from polluted European harbour waters but may result in the transportation of potentially harmful phytoplankton species from the regional seas Macdonald and Davidson, There are no reasons to assume that shellfish intoxication can be predicted by the properties of the regional area.
Incomplete elimination of harmful organisms is caused by the incomplete discharge of water and sediments in the ballast tank during reballasting Zhang and Dickman, The causative toxin the excitatory amino acid domoic acid or DA was produced by the diatom species Pseudo-nitzschiapungens f. The causative toxins, the ciguatoxins, accumulate through the food chain, from small herbivorous fish grazing on the coral reefs into organs of bigger carnivorous fish that feed on them Angibaud and Rambaud, ; Lehane, The toxin was found widely from California to Washington, and was also found unexpectedly in crabs, the first time this toxin was demonstrated in a crustacean.
In Septemberthe unexplained deaths of pelicans and cormorants in Monterey Bay, California were attributed to an outbreak of DA poisoning produced by a related diatom Pseudo-nitzschia australis. DSP toxin production may vary considerably among dinoflagellate species and among regional and seasonal morphotypes in one species. The PSP toxins are produced mainly by dinoflagellates belonging to the genus Alexandrium, which may occur both in the tropical and moderate climate zones.
Maeinas Novemberat least eight people in the Netherlands became biotoxinad after eating mussels Mytilus edulis cultivated at Killary Harbour, Ireland. Diarrhoeic Shellfish Poisoning DSP in humans is caused by the ingestion of contaminated bivalves such as mussels, scallops, oysters or clams. During the past two decades, the frequency, intensity and geographic distribution of harmful algal blooms has increased, along with the number of toxic compounds found in the marine food chain.
In earlymore than human shellfish poisonings were reported from New Zealand caused by an organism similar to G. Changed patterns of land use, such as deforestation, can also cause shifts marjnas phytoplankton species composition by increasing the concentrations of humic substances in land runoff.
DSP toxins can be divided into different groups depending on chemical structure.
These cysts sink to the bottom of the sea and accumulate at biiotoxinas borderline of water and sediment where they over-winter. At this time, ASP caused ,arinas deaths and cases of acute human poisoning following the consumption of blue mussels.
The explosive growths sometimes appear during changes in weather conditions but important contributing causes may be variations in upwellings, temperature, transparency, turbulence or salinity of the water, the concentration of dissolved nutrients, wind or surface illumination Bower et al.
At present, ciguatera is the most common type of marine food poisoning worldwide and, with an estimated 10 to 50 people worldwide suffering from the disease annually, it constitutes a global health problem De Fouw et al. Until now, five groups of shellfish toxins have been biotosinas, namely:. In addition, a slowly progressing paralysis was observed in the mouse assay using the mussel extracts.