Changes in the quality of chromophoric dissolved organic matter leached from senescent leaf litter during the early decomposition.

Chromophoric dissolved organic matter (CDOM) leached from leaf litter is a major source of humus in mineral soil of forest ecosystems. While their functions and refractoriness depend on the physicochemical structure, there is little information on the quality of CDOM, especially for that leached in the very early stages of litter decomposition when a large amount of dissolved organic matter (DOM) is leached. This study aimed to better understand the variations/changes in the composition of CDOM leached from senescent leaf litter from two tree species during the early stage of decomposition.

Influence of irrigated paddy fields on the fluorescence properties of fluvial dissolved organic matter.

This study investigated seasonal and geographical variation in the fluorescence properties of dissolved organic matter (DOM) in a river system that includes rice paddy fields in its watershed. The river system covers a northern area of the main island of Japan, and between 6 and 45% the watershed area of the tributaries is paddy fields. Water samples were collected monthly from eight tributaries for 1 yr, and the fluorescence properties of DOM were monitored by combined excitation-emission matrix (EEM) and parallel factor analysis.