Natural organic matter differently modulates growth of two closely related coccal green algal species.

Background And Aim: Humic substances (HS) comprise the majority of dead and living organic carbon, including organisms. In the environment, they are considered to be chemically inert or at least refractory. Recent papers, however, show that HS (including natural organic matter-NOM, isolated by reverse osmosis) are natural chemicals which interact with aquatic organisms.