Stratigraphic Distribution of Amino Acids in Peats from Cedar Creek Bog, Minnesota, and Dismal Swamp, Virginia1

Abstract

The concentration of several alpha‐amino acids obtained by acid hydrolysis at various levels in Cedar Creek Bog and Dismal Swamp has been determined. Seven amino acids are consistently present in the natural accumulations: glycine, aspartic acid, glutamic acid, threonine, alanine, valine, and leucine. Alanine occurs in the highest concentrations, attaining about 22 µmol/g in the samples investigated. Free amino acids were absent or very rare in both the bog waters and waters squeezed from the peats. Attempts to detect proteins in these substances by means of paper electrophoresis were unsuccessful. Fibrous proteins may be present, however.In both peat deposits there is a greater concentration of amino acids at depths of a few feet than in the uppermost peat layers. Hydrolysis of a humic acid preparation from Minnesota peat yielded the same suite of amino acids given above. It is therefore suggested that the amino acids in our peat hydrolyzates mainly occurred adsorbed by, or linked to, the humic acid micelles rather than as proteinaceous compounds.The distribution of amino acids in Cedar Creek Bog peat suggests two periods of trophication, one beginning approximately 12,000 years ago in Mankato time and ending with the so‐called thermal maximum perhaps as late as 6,000 years ago, the other beginning after the thermal maximum and continuing to the present. Evidence of more than one cycle of peat development in the Lake Drummond area of Dismal Swamp is lacking.