Toxic dinoflagellates can directly harm other organisms during bloom periods by secreting their ...

A bloom of non-toxic dinoflagellates can cause a serious reduction in the nutrients available for other autotrophic organisms in the area of the bloom. Once these dinoflagellates deplete the nutrients in the water, they die and are decomposed by microbes. This decomposition can lead to the depletion of oxygen in the water column, which can harm other organisms. Finally, a bloom of non-toxic dinoflagellates can reduce the clarity of the water column, leading to the reduction in the amount of available light to benthic photosynthesizers.