Subject: Do you know why dinoflagellates produce toxins?

I am asking this question because all the research that I have come up with has 
mentioned nothing about why they produce the toxin, it mentions what the toxin 
does, but not why it was produced. I'm trying to become a biology teacher in a 
highschool, and I taught a lesson on Red tides. A student, of course, came up 
with the one question that I did not know, "why are they produced?" And I CANT 
find it anywhere. Do they produce it because of a predator-prey relationship 
or? Thanks for your time. Please let me know, so I can go back and tell the 
class that I am working with the answer!
Mary

Re: Do you know why dinoflagellates produce toxins?