Of the freshwater habitats, stream side pools within rainforest and epiphytic communities in a calcareous lake were the richest in taxa. The surfaces of sand, submerged angiosperm leaves and macro algae were the richest marine habitats.
Although diatoms have been collected in the Philippines previously, only one collection was made prior to 1984, and nothing had been published on Palawan diatoms. In addition, studies anywhere of diatom floras flowing over magic and magic-plutonic (heavy-metal rich) rocks were limited to a study by Manguin in 1962. These collections and results thus have additional importance.
33 samples were taken from 18 localities:
A total of 348 species, varieties and forms in 74 genera were found, the majority of which were new Philippine records. Navicula was represented by 51 taxa, Mastagloia by 39, Amphora by 22 and Nitschia by 22.
