He didn't mention local bedrock geology, but one experience I had with a student several years ago might prove helpful. She, too, had brought back beautiful, rich organics from a marsh in Bermuda that, despite our best efforts, seemed to be all but devoid of pollen. On a hunch, I checked the pH of the sediments - and came up with an 8.0. Despite the richness of the organics, the alkaline conditions produced by the local limestone was probably responsible for near-complete pollen degradation. Samples collected more recently, from sites farther removed from the bog margins, showed good pollen concentrations and are producing valuable data.
Good science consists mostly of play disguised as work.
I often process sediments that have pH values higher than 8.0 and get good pollen records. Often the sediments are not particularly organic. In my experience, the pH needs to be much higher to result in the obliteration of pollen from the sample. I had not responded to the discussion on removing organics because I have never used such harsh measures. I have varied the times for acetolysis.