5 research outputs found
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Lichens and mosses on shrub-steppe soils in southeastern Washington
The purpose of this study was to identify the lichens and mosses found on soils of the shrub-steppe at the Hanford Site in southeastern Washington. Twelve sites between 133 and 447 m and one at 807 m elevation were intensively sampled. Twenty-nine lichens and six moss species were identified. Three lichens were considered undescribed species. Based on comparison with other studies and herbarium records, we conclude the soil lichen flora of the Hanford Site is substantially different than that of the Great Basin or of the shrub-steppe in Idah
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Population Characteristics and Seasonal Movement Patterns of the Rattlesnake Hills Elk Herd - Status Report 2000
Wildlife biologists documented an isolated elk population in 1972 on the U.S. Department of Energy's (DOE) Hanford Site. Since then the herd has grown, exceeding 800 animals in 1999. Limited harvests on adjacent private lands have occurred since 1986. The large herd size coupled with limited annual harvest have increased concerns about private land crop damages, vehicle collisions, degradation of the native environment, and the herd's use of radiologically controlled areas on the Hanford Site. As a result, in 1999, a decision was made by the Washington Department of Fish and Wildlife (WDFW) (animal management), the U.S. Fish and Wildlife Service (USFWS) (land management), and DOE (landowner) to conduct a large-scale animal roundup to remove elk from the DOE-owned lands and relocate them to distant areas within Washington State. The interagency roundup and relocation occurred in spring 2000. This report presents the current status of the herd size and composition, annual removal estimates, and some limited seasonal area-use patterns by several radio-collared elk subsequent to the large-scale elk roundup. The elk herd maintained an approximate 25% annual increase until 2000. A large harvest offsite in 1999 coupled with the large-scale roundup in spring 2000 reduced herd size to the current estimate of 660 animals. As of August 2000, the herd consisted of 287 (43%) males, 282 (42%) females, and 91 (13%) calves. There has been a notable cycling of calf recruitment rates throughout the 1990s and in 2000. Elk home-range estimates revealed a substantial decrease in summer home ranges in 2000, presumably, in part, as a result of the summer 2000 Hanford Site wildfire. Movement analysis also determined that, as population size increased, so has the frequency and extent of the animals' offsite movements, particularly on private lands adjacent to the Hanford Site in both spring and summer seasons. The frequency and duration of movements by male elk onto the central portions of the Hanford Site has increased substantially as the population increased
Conditional deletion of ferritin h in mice reduces B and T lymphocyte populations.
The immune system and iron availability are intimately linked as appropriate iron supply is needed for cell proliferation, while excess iron, as observed in hemochromatosis, may reduce subsets of lymphocytes. We have tested the effects of a ferritin H gene deletion on lymphocytes. Mx-Cre mediated conditional deletion of ferritin H in bone marrow reduced the number of mature B cells and peripheral T cells in all lymphoid organs. FACS analysis showed an increase in the labile iron pool, enhanced reactive oxygen species formation and mitochondrial depolarization. The findings were confirmed by a B-cell specific deletion using Fth(lox/lox) ; CD19-Cre mice. Mature B cells were strongly under-represented in bone marrow and spleen of the deleted mice, whereas pre-B and immature B cells were not affected. Bone marrow B cells showed increased proliferation as judged by the number of cells in S and G2/M phase as well as BrdU incorporation. Upon in vitro culture with B-cell activating factor of the tumor necrosis factor family (BAFF), ferritin H-deleted spleen B cells showed lower survival rates than wild type cells. This was partially reversed with iron-chelator deferiprone. The loss of T cells was also confirmed by a T cell-specific deletion in Fth(lox/lox) ;CD4-Cre mice. Our data show that ferritin H is required for B and T cell survival by actively reducing the labile iron pool. They further suggest that natural B and T cell maturation is influenced by intracellular iron levels and possibly deregulated in iron excess or deprivation
Climate dependence of feldspar weathering in shale soils along a latitudinal gradient
Although regolith, the mantle of physically, chemically, and biologically altered material overlying bedrock, covers much of Earthâs continents, the rates and mechanisms of regolith formation are not well quantified. Without this knowledge, predictions of the availability of soil to sustain Earthâs growing population are problematic. To quantify the influence of climate on regolith formation, a transect of study sites has been established on the same lithology â Silurian shale â along a climatic gradient in the northern hemisphere as part of the Susquehanna Shale Hills Critical Zone Observatory, Pennsylvania, USA. The climate gradient is bounded by a cold/wet end member in Wales and a warm/wet end member in Puerto Rico; in between, mean annual temperature (MAT) and mean annual precipitation (MAP) increase to the south through New York, Pennsylvania, Virginia, Tennessee and Alabama. The site in Puerto Rico does not lie on the same shale formation as the Appalachian sites but is similar in composition. Soils and rocks were sampled at geomorphologically similar ridgetop sites to compare and model shale weathering along the transect. Focusing on the low-concentration, non-nutrient element Na, we observe that the extent and depth of Na depletion is greater where mean annual temperature (MAT) and precipitation (MAP) are higher. Na depletion, a proxy for feldspar weathering, is the deepest reaction documented in the augerable soil profiles. This may therefore be the reaction that initiates the transformation of high bulk-density bedrock to regolith of low bulk density. Based on the shale chemistry along the transect, the time-integrated Na release rate (QNa) increases exponentially as a function of MAT and linearly with MAP. NY, the only site with shale-till parent material, is characterized by a QNa that is 18 times faster than PA, an observation which is attributed to the increased surface area of minerals due to grinding of the glacier and kinetically limited weathering in the north. A calculated apparent Arrhenius-type temperature dependence across the transect (excluding NY) for the dissolution of feldspar (Na depletion) is 99 ± 15 kJ molâ1, a value similar to field-measured values of the activation energy (14â109 kJ molâ1) or laboratory-measured values of the enthalpy of the albite reaction (79.8 kJ molâ1). Observations from this transect document that weathering losses of Na from Silurian shale can be understood with models of regolith formation based on chemical and physical factors such that weathering progresses from kinetically limited sites (Wales to AL) to the transport-limited site in Puerto Rico. Significant advances in our ability to predict regolith formation will be made as we apply more quantitative models to such transect studies on shales and other rocks types