Adsorption and release of amino acids from epilithic biofilms in streams

SUMMARY. I. Stream sediment with a natural biofilm generally adsorbed more glycine, aspartic acid, and lysine than sterile sediment. Lysine was adsorbed to a greater extent than the other two amino acids. 2. In the presence of Ca2+, adsorption of aspartic acid increased and adsorption of lysine decreased. Glycine was not affected. 3. Stream sediment preferentially removed amino acids with a positive charge or a polar R group from maple leaf leachate. 4. It is estimated that stream invertebrates may have access to a maximum of 7.3% of the amino acids present in epilithic biofilms. More amino acids were available from biofilms exposed to leaf leachate.