Filters: Tags: Particulate organic matter (X)2 results (6ms)
Carbon and nitrogen isotopic compositions of particulate organic matter in four large river systems across the United States
Riverine particulate organic matter (POM) samples were collected bi-weekly to monthly from 40 sites in the Mississippi, Colorado, Rio Grande, and Columbia River Basins (USA) in 1996â€“97 and analysed for carbon and nitrogen stable isotopic compositions. These isotopic compositions and C : N ratios were used to identify four endmember sources of POM: plankton, fresh terrestrial plant material, aquatic plants, and soil organic material. This large-scale study also incorporated ancillary chemical and hydrologic data to refine and extend the interpretations of POM sources beyond the source characterizations that could be done solely with isotopic and elemental ratios. The ancillary data were especially useful for differentiating...
Soil moisture surpasses elevated CO2 and temperature as a control on soil carbon dynamics in a multi-factor climate change experiment
Some single-factor experiments suggest that elevated CO2 concentrations can increase soil carbon, but few experiments have examined the effects of interacting environmental factors on soil carbon dynamics. We undertook studies of soil carbon and nitrogen in a multi-factor (CO2 Ã— temperature Ã— soil moisture) climate change experiment on a constructed old-field ecosystem. After four growing seasons, elevated CO2 had no measurable effect on carbon and nitrogen concentrations in whole soil, particulate organic matter (POM), and mineral-associated organic matter (MOM). Analysis of stable carbon isotopes, under elevated CO2, indicated between 14 and 19% new soil carbon under two different watering treatments with as...