The analytical pyrolysis of particulate residues of decomposing Myriophyllum heterophyllum

Abstract

Mature tissue and particulate organic decomposition products of the submersed aquatic plant Myriophyllum heterophyllum Michx were analysed by Curie-point pyrolysis low voltage ionisation mass spectrometry. Decomposition was performed under controlled aerobic and anaerobic conditions at 10°C and 25°C for 180 days. Particulate components were analysed at 0, 2, 4, 10, 24, 48, 90 and 180-day intervals. The composition of the native plant material changed markedly during the decomposition period, as was demonstrated qualitatively and quantitatively by factor analysis of the pyrolysis mass spectrometric data. The particulate residues were characterized by increasing amounts of proteins and N-acetyl aminosugars, especially at the longer decomposition intervals. Decreasing weight loss correlated with an increasing presence of these polymers in or on the decomposing plant structural matter. This process took place faster at the higher decomposition temperatures. The anaerobic processes were more sensitive to temperature than the aerobic processes.