Red tides in warm coastal water develop due to the abundance of ___.

Step-by-step solution

Dinoflagellates are unicellular plankton and they belong to the kingdom Protista. 90% of dinoflagellates live in the ocean and they are autotrophs which means they can prepare their own food through photosynthesis. Dinoflagellates have two flagella and when disturbed they glow causing the ocean to light up. In dinoflagellates, red tides are caused by Gonyaulax, Gymnodinium, Alexandrium, etc.