Molecular filters, composed of cellulose acetate and nitrate membranes, may be used for the quantitative estimation of microplankton populations, for the determination of suspended organic and inorganic matter in natural waters, and in studies of photosynthetic productivity by phytoplankton cells in collected samples....
Goldberg, Edward D., Marjorie Baker, and Denis L. Fox. 1952. "Microfiltration in oceanographic research I. Marine sampling with the molecular filter." Journal of Marine Research 11, (2). https://elischolar.library.yale.edu/journal_of_marine_research/770