This is a good point that I had never thought about, even though I've worked with fire.
Apparently there was a big algae bloom in 1997 that killed coral and fish for a 400 km stretch in Indonesia. It was later attributed to nutrient fallout from Sumatran forest fires. Of course, in Southern California, the erosion will be a lot greater after fires, also causing large nutrient inputs.
So you're right that the S. California fires are likely to influence marine food webs if wind patterns are sending smoke out to sea, and also from increased nutrients in runoff.Thanks for asking, this is something I'll mention to my students in the future.