Isolation of Colloidal Fibrils from Lake Water by Physical Separation Techniques

Abstract

A colloid fraction, highly enriched for organic fibrils, can be isolated routinely by physical means. The physical isolation scheme used here provides gram quantities of un-denatured samples in a short time from the epilimnion of a small mesotrophic lake. The total scheme is described in detail and is accompanied by an assessment of yield and contamination at each individual step using a transmission electron microscope as a monitor. The potential importance of organic fibrils is emphasized by a 1980 summer measure showing a fibril fraction to contain three times more carbon than the conventional particulate organic carbon fraction (POC) and 33% of the total dissolved organic carbon (DOC).Key words: colloids, hollow-fiber ultrafiltration, dissolved organic carbon