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Present understanding of the global carbon cycle is limited by uncertainty over soil-carbon dynamics 1±6. The clearing of the world's forests, mainly for agricultural uses, releases large amounts of carbon to the atmosphere (up to 2 3 10 15 g yr 2 1), much of which arises from the cultivation driving an accelerated decomposition of soil organic matter 1±4.(More)
Elevated concentrations of atmospheric CO2 increase plant biomass, net primary production (NPP) and plant demand for nitrogen (N). The demand for N set by rapid plant growth under elevated CO2 could be met by increasing soil N availability or by greater efficiency of N uptake. Alternatively, plants could increase their nitrogen-use efficiency (NUE), thereby(More)
Boreal forests contain large amounts of stored soil carbon and are susceptible to periodic disturbance by wildfire. This study evaluates the relationship between post-fire changes in soil temperature, moisture, and CO 2 exchange in paired burned and control stands of three Alaskan forest systems: Picea mariana (Mill.) BSP, Picea glauca (Moench) Voss, and(More)
Understanding what governs patterns of soil delta15N and delta13C is limited by the absence of these data assembled throughout the development of individual ecosystems. These patterns are important because stable isotopes of soil organic N and C are integrative indicators of biogeochemical processing of soil organic matter. We examined delta15N of soil(More)
Although low solubility and slow cycling control P circulation in a wide range of ecosystems, most studies that evaluate bioavailability of soil P use only indices of short-term supply. The objective here is to quantify changes in P fractions in an Ultisol during the growth of an old-field pine forest from 1957 to 2005, specifically changes with organic P(More)
Prescribed fire, a practice applied annually to about 10(6) hectares of forests in the southeastern United States, had limited effects on soils, nutrient cycling, and hydrologic systems of a coastal plain pine forest. Hydrologic fluxes of nitrogen, phosphorus, sulfur, and basic cations, from burned pine litter to ground and stream waters, are not likely to(More)
Because the root system of a mature pine tree typically accounts for 20-30s of the total tree biomass, decomposition of large lateral roots and taproots foliowin, 0 forest harvest and re-establishment potentially impact nutrient supply and carbon sequestration in pine systems over several decades. If the relationship between stump diameter and decomposition(More)
Genetic screens in Drosophila melanogaster and other organisms have been pursued to filter the genome for genetic functions important for memory formation. Such screens have employed primarily chemical or transposon-mediated mutagenesis and have identified numerous mutants including classical memory mutants, dunce and rutabaga. Here, we report the results(More)