Many mixotrophic and some heterotrophic dinoflagellates are known to cause red tides or harmful blooms that result in large-scale mortality of fish and shellfish.
Studies on red tides have been conducted to determine the mechanism of outbreak and the persistence of red tides caused by mixotrophic dinoflagellates such as Karenia brevis, Prorocentrum donghaiense and Prorocentrum minimum in low nutrient concentration waters.
In the case of serial red tides, one mixotrophic dinoflagellate species is dominated by another mixotrophic species in rapid succession over a short span of days.
A possible explanation for the occurrence of different dominant mixotrophic dinoflagellates during serial red tides is the ability of mixotrophic dinoflagellates to feed on both heterotrophic bacteria and cyanobacteria (such as Synecchococcus) spp.,
which provide limiting nutrients such as phosphorus, and nitrogen simultaneously.
It is proposed that during serial red tides, feeding by larger mixotrophic dinoflagellates on smaller species may be a driving force for the succession of dominant species.
Nitrogen and phosphorus is taken up by direct transfer of the materials and energy between the mixotrophic dinoflagellates; therefore, nutrient supply does not rely on the release of nitrogen and phosphorus by other organisms.
Hence, mixotrophy can cause uncoupling between nutrient concentrations and the abundance of mixotrophic dinoflagellates in natural environments.

Red tides are a type of harmful algal bloom (HABs); both are the result of massive proliferation of algae that result in very high concentrations of cells that visibly colour the water.
The very high levels of biomass in Red Tides or HABs can have direct toxic effects through the release of toxic compounds or indirect effects through oxygen depletion on mammals, fish, shellfish, and humans.
PSP (Paralytic Shellfish Poisoning) is one example of a toxin that is produced by dinoflagellates that can have lethal consequences if contaminated shellfish are ingested; the toxin is a neuro-inhibitor that is concentrated in the flesh of bivalves and molluscs that have fed on toxic algae The toxin concentrations can cause harmful and even deadly effects on humans and marine mammal populations that feed on contaminated shellfish.
Many mixotrophic and some heterotrophic dinoflagellates are known to cause red tides or harmful blooms that result in large-scale mortality of fish and shellfish. Studies on red tides have been conducted to determine the mechanism of outbreak and the persistence of red tides caused by mixotrophic dinoflagellates such as Karenia brevis, Prorocentrum donghaiense and Prorocentrum minimum in low nutrient concentration waters. In the case of serial red tides, one mixotrophic dinoflagellate species is dominated by another mixotrophic species in rapid succession over a short span of days. A possible explanation for the occurrence of different dominant mixotrophic dinoflagellates during serial red tides is the ability of mixotrophic dinoflagellates to feed on both heterotrophic bacteria and cyanobacteria (such as Synecchococcus) spp., which provide limiting nutrients such as phosphorus, and nitrogen simultaneously. It is proposed that during serial red tides, feeding by larger mixotrophic dinoflagellates on smaller species may be a driving force for the succession of dominant species. Nitrogen and phosphorus is taken up by direct transfer of the materials and energy between the mixotrophic dinoflagellates; therefore, nutrient supply does not rely on the release of nitrogen and phosphorus by other organisms. Hence, mixotrophy can cause uncoupling between nutrient concentrations and the abundance of mixotrophic dinoflagellates in natural environments.
Red tides are a type of harmful algal bloom (HABs); both are the result of massive proliferation of algae that result in very high concentrations of cells that visibly colour the water. The very high levels of biomass in Red Tides or HABs can have direct toxic effects through the release of toxic compounds or indirect effects through oxygen depletion on mammals, fish, shellfish, and humans. PSP (Paralytic Shellfish Poisoning) is one example of a toxin that is produced by dinoflagellates that can have lethal consequences if contaminated shellfish are ingested; the toxin is a neuro-inhibitor that is concentrated in the flesh of bivalves and molluscs that have fed on toxic algae The toxin concentrations can cause harmful and even deadly effects on humans and marine mammal populations that feed on contaminated shellfish.
Mixotrophic dinoflagellate