Sediment-water fluxes were measured on transects across the northern Alaskan continental margin. Dissolved oxygen fluxes approximated total carbon dioxide fluxes when fluxes were low, but oxygen underestimated the higher total carbon dioxide fluxes. This follows a diagenetic model in which aerobic sediments occur below 86 μmol total carbon dioxide m -2 h -1 and anaerobic conditions intensify wi...

Soil organic carbon (C) dynamics have been used to assess sustainable land managements in forest ecosystems. Impact, defined as intensive forms of land use that affect the soil function, can change C quantity and quality in soils, leading to a progressive degradation of the ecosystems. Soil CO2 effluxes were studied in five transects located at the Fort Benning military reservation in west-cent...

Soil carbon (C) losses and soil translocation from tillage operations have been identified as causes of soil degradation and soil erosion. The objective of this work was to quantify the variability in tillage-induced carbon dioxide (CO2) loss by moldboard (MP) and chisel (CP) plowing across an eroded landscape and relate the C loss to soil properties. The study site was a 4 ha wheat (Triticum a...

Aerodynamic roughness length 0 ) and displacement height 0 ) are important surface parameters for estimating surface fluxes in numerical models. These parameters are generally determined from wind flow characteristics using logarithmic wind profiles measured at a meteorological tower or by balloon release. It would be an advantage to use measurements of land surface characteristics instead of w...

We examined the influence of both the proximity and extent of human developments and paved roads on the presence of the predatory, non-indigenous, red imported fire ant (Solenopsis invicta). This species was inadvertently introduced into the United States at the port of Mobile, Alabama, around 1930 and rapidly spread to many southeastern states, including Florida. More recently, S. invicta colo...

hyrcanian forests in northern slope of alborz support high bird richness and abundance same as central of europe. in this study, efficiency of different methods including fixed-width transect, variable-width transect, fixed-radius point count and variable circular plot samplings were compared in order to present the most reliable methods for surveying and monitoring of diurnal forest birds in f...

this study investigates the relationship between litter quality and aerial parts of plant on c, n, k, p and c/n ratio of soil in four rangeland species including agropyron intermedium, bromus tomentellus, eurotia ceratoides and kochia prostrata. after recognizing the sites of these species in hamand absard located in 65 km of northern tehran, at the end of growing season, samples of litter, aer...