While there has been a great deal of guessing over the cause of the toxic algae bloom , there is no evidence that it is being caused by pollution or that there has been an increase in the length or frequency of red tide outbreaks . While there has been a great deal of conjecture over the cause of the toxic algae bloom , there is no evidence that it is being caused by pollution or that there has been an increase in the duration or frequency of red tide outbreaks .