Miracle-dz/UniFAR-FTUs huggingface dataset:
Influence of Increasing Prosopis glandulosa on Herbaceous Diversity and Composition on Two Soils in Southern Mixed-Grass Prairie

We evaluate how increasing cover levels of the tree Prosopis glandulosa Torr. influence herbaceous species richness and composition in two soil-landscape positions in the mixed-grass prairie of the southern Great Plains, U.S.A. Herbaceous species biomass and composition and P. glandulosa cover were monitored on silt-loam bottomlands and clay-loam uplands, in spring, summer, and fall from 1995 to 2001 in 8 paddocks varying in size from 1,283 to 2,130 ha. P. glandulosa trees were closely associated with herbaceous plant composition and richness in different ways on each of the soils. Herbaceous species richness was greater on silt-loam bottoms than clay-loam uplands and decreased little except at the highest P. glandulosa cover levels on both soils. Herbaceous vegetation differed between soil sites and between low (<15%), mid (between 20 and 55%), and high (>60%) P. glandulosa cover levels. The greatest species richness on both soils occurred in areas dominated by herbaceous plants and the least at the highest levels of P. glandulosa cover. On both soils increasing P. glandulosa cover from 0 to 100% was associated with significant declines in herbaceous biomass with C4 tall grasses, C4 mid-grasses, and forbs, small declines with C4 short grasses, and significant increases with C3 annual grasses. Both cool and warm season forb herbaceous functional groups declined with increasing P. glandulosa cover. These results indicate that P. glandulosa reduction on the bottomland sites would yield the greatest benefits in species richness and herbage productivity.
Comparison of Aquifer Sustainability Under Groundwater Administrations in Oklahoma and Texas 1

Mittelstet, Aaron R. , Michael D. Smolen, Garey A. Fox, and Damian C. Adams, 2011. Comparison of Aquifer Sustainability Under Groundwater Administrations in Oklahoma and Texas. Journal of the American Water Resources Association (JAWRA) 1‐8. DOI: 10.1111/j.1752‐1688.2011. 00524.x
Variation of ice crystal size, shape, and asymmetry parameter in tops of tropical deep convective clouds

The variation of ice crystal properties in the tops of deep convective clouds off the north coast of Australia is analyzed. Cloud optical thickness, ice effective radius, aspect ratio of ice crystal components, crystal distortion parameter and asymmetry parameter are simultaneously retrieved from combined measurements of the Moderate Resolution Imaging Spectroradiometer (MODIS) and Polarization and Directionality of the Earth's Reflectances (POLDER) satellite instruments. The data are divided into periods with alternating weak and strong convection. Mostly plate‐like particle components with aspect ratios closer to unity and lower asymmetry parameters characterize strongly convective periods, while weakly convective periods generally show lower aspect ratios, relatively more column‐like shapes and somewhat greater asymmetry parameters. Results for strongly convective periods show that, with increasing cloud top temperature, the distortion parameter generally decreases, while the asymmetry parameter and effective radius increase. For one of the strongly convective periods, the rate at which effective radii increase with cloud top temperature is more than double that of the other periods, while the temperature dependence of the other microphysical quantities for this period is substantially weaker. Atmospheric state analysis indicates that these differences are concurrent with differences in middle‐to‐upper tropospheric zonal wind shear. The observed variation of microphysical properties may have significant effects on the shortwave radiative fluxes and cloud absorption associated with deep convection. Additionally, MODIS collection 5 effective radii are estimated to be biased small with an artificially narrow range. Collection 6 products are expected to have less severe biases that depend on cloud top temperature and atmospheric conditions.
Macrofauna and nutrient cycling in the Swan River Estuary, Western Australia: experimental results

This study investigated the effect of benthic macrofauna on nutrient fluxes. The influence of the macrofauna on nutrients released from the sediments was investigated experimentally in the laboratory using sediment cores from the Swan–Canning Estuary. Excretion rates of common benthic species were also measured to quantify the role of the macrofauna in estuarine nutrient cycling.
Jurassic Tectonic Revolution in China and New Interpretation of the “Yanshan Movement”

Abstract: With acquisition and accumulation of new data of structural geological investigations and high‐resolution isotopic dating data, we have greatly improved our understanding of the tectonic events occurring in eastern China during the period from the Late Jurassic to Early Cretaceous and may give a new interpretation of the nature, timing and geodynamic settings of the “Yanshan Movement”. During the Mid‐Late Jurassic (165±5 Ma), great readjustment of plate amalgamation kinematics took place in East Asia and the tectonic regime underwent great transformation, thus initiating a new tectonic regime in which the North China Block was the center and different plates converged toward it from the north, east and southwest and forming the “East Asia convergent” tectonic system characterized by intracontinental subduction and orogeny. As a consequence, the crustal lithosphere of the East Asian continent thickened considerably during the Late Jurassic, followed immediately by Early Cretaceous substantial lithospheric thinning and craton destruction featured by drastic lithospheric extension and widespread volcano‐magmatic activities, resulting in a major biotic turnover from the Yanliao biota to Jehol Biota. Such a tremendous tectonic event that took place in the continent of China and East Asia is the basic connotation of the “Yanshan Movement”. In the paper, according to the deformation patterns, geodynamic settings and deep processes, the “Yanshan Movement” is redefined as the Late Jurassic East Asian multi‐directional plate convergent tectonic regime and its associated extensive intracontinental orogeny and great tectonic change that started at ˜165±5 Ma. The substantial lithospheric attenuation in East China is considered the post‐effect of the Yanshanian intracontinental orogeny and deformation.
Sublithospheric small‐scale convection and its implications for the residual topography at old ocean basins and the plate model

[1] The seafloor topography and heat flux differ significantly from the predictions of the half-space cooling (HSC) model at old ocean basins. Understanding the deviations has important implications for thermal evolution of oceanic lithosphere and large-scale mantle dynamics. A widely used model that explains significant fraction of the deviations is the plate model, but the dynamical feasibility of the plate model has never been demonstrated. In this study, we investigated the effects of sublithospheric small-scale convection (SSC) and of internal heating on seafloor heat flux and topography and mantle thermal structure, and we examined the dynamic feasibility of the plate model by formulating high- resolution two-dimensional numerical models of mantle convection with strongly temperature- and depth-dependent rheology. We found that mantle convection with tectonic plates often leads to formation of a broad thermal anomaly below old lithosphere where the mantle is not cooled by subducted slabs and heat transfer is less efficient because of thick lithosphere, especially when significant internal heating is present. This trapped heat may exist in the middle mantle when the SSC is absent, and it may also be redistributed by the SSC to shallow depths to reheat the lithosphere and to homogenize mantle temperature. When internal heating accounts for >∼60% of the total heat output, the trapped heat may provide sufficient heat supply to preferentially reheat old lithosphere via SSC while maintaining uniform mantle temperature. We suggest that the trapped heat and the SSC are responsible for the residual heat flux and topography at old ocean basins relative to the HSC model predictions. Our models also show that for the plate model to be dynamically viable, both the SSC and significant internal heating (>60%) are necessary. This is because only the SSC in a mantle with significant internal heating can erode and reheat the lithosphere while maintaining a nearly constant mantle temperature below lithosphere, which is the basic assumption of the plate model. With the viscosity structure and internal heating rate for the present-day mantle, we think that the plate model is dynamically viable.
Compositional and metamorphic controls on velocity and reflectivity in the continental crust: An example from the Grenville Province of eastern Québec

We present velocity and density data for a suite of gabbros and metagabbros over a range of metamorphic grades, from subgreenschist to the eclogite facies. Most of these rocks have a mesocratic protolith with overlapping bulk chemistry ranges providing an opportunity to investigate the systematics of mineralogy and physical properties across a wide range of metamorphic grades with minimal compositional variation. In addition, more mafic gabbros in the eclogite facies were also investigated in order to take into account variations in the extent of transformation of gabbro to eclogite controlled by bulk chemistry. The physical properties data are used as the basis for a first-order crustal model composed of granitic, anorthositic, and gabbroic components. The objective of constructing the crustal model is to evaluate the relative contribution of compositional variation and metamorphism to the velocity, density, and reflectivity structure of the continental crust. The model suggests that in the upper crust, if fracture porosity is neglected, composition dominates the velocity and density structure, while in the middle and lower crust, composition and metamorphism play equally important roles. Simulations designed to predict potential reflection coefficient size distributions for the various bulk chemistries and mineralogies in the crustal model indicate step increases in the potential for large reflection coefficients that are dominantly controlled by metamorphic grade. Step increases in reflectivity are predicted between the lower and upper amphibolite facies and between incompletely and completely eclogitized metagabbros in the eclogite facies. We also consider several alternative mixing models which account for the effects of one of the three lithologic components occurring as isolated bodies rather than perfectly mixed with the other two components. These models indicate a reduction of the potential for large reflection coefficients by as much as 50%, emphasizing the importance of the degree of mixing for crustal reflectivity.
Measurements of electric fields in thunderclouds

A series of measurements of electric fields inside active thunderclouds in central New Mexico with instrumented rockets shows that very intense fields (up to 4×105 V/m) do exist, although they are rare. In a tabulation of the peak values of the electric field along each trajectory, 4.3×104 V/m is the median value. Peak values greater than 105 V/m were encountered only 6 times out of a total of 61 cases. Two examples of very intense fields are presented as case studies.
Deep sea-floor evidence of past ice streams off the Antarctic Peninsula

The past existence of a giant ice stream off the northern end of the Antarctic Peninsula is suggested by a convex-upward, elongated sediment body now at a mean water depth of 1000 m. Because of its morphological characteristics, i.e., a set of parallel to subparallel ridges and grooves to 100 km long, with an overall width of 25 km, we call this depositional body a bundle structure. We hypothesize that bundle structures form by accumulation of basal deformation till under their parent ice streams. From its location, size, and overall characteristics the bundle structure described here constitutes the best preserved, largest, deepest, and relatively low latitude evidence of giant ice streams that flowed offshore Antarctica during glacial maxima. Bundle structures reveal the very dynamic behavior of ice caps in the northern Antarctic Peninsula during the last glacial maximum, with catchment areas draining rapidly under marine-based critical subglacial conditions. Bundle structures represent a new megascale streamlined glacial landform.
Environmental changes of the last three centuries indicated by siliceous microfossil records from the southwestern Baltic Sea

Four short sediment cores from the southwestern Baltic Sea were analysed with respect to their content of siliceous microfossils. The aim was to detect and date changes in the composition of the diatom flora and to link these changes to variations in the anthropogenic load of nutrients during the last century. The study shows that the most significant change in the diatom assemblages occurred 130-140 years ago. The change is recorded in the sediments as a shift from periphytic diatom taxa to a predominance of planktonic taxa. This indicates that the photic layer has decreased in depth, probably due to eutrophication of the Baltic Sea, which consequently began to affect the area investigated approximately AD 1850. To support the results of a changing ratio of periphytic to planktonic diatoms, diatom accumulation rates were calculated. In general, the diatom accumulation rate data show a decrease in the periphytic accumulation rates and an increase in the planktonic accumulation rates towards the sediment surface. Some indications of a colder climate are recorded in the sediments approximately 230 years ago. These results are in accordance with the record of maximum extent of sea ice in the same area and are suggested to represent a late stage in the ‘Little Ice Age’.
Equation of state and phase stability of mantle perovskite up to 140 GPa shock pressure and its geophysical implications

We performed shock wave experiments on a natural pyroxene with chemical composition close to (Mg0.92, Fe0.08)SiO3 and initial density of 3.06 g/cm3, between 48 and 140 GPa. The relationship of shock wave velocity us and particle velocity up can been described linearly by us = 3.76(±0.24) + 1.48(±0.07) up (km/s). The model Hugoniot for the assemblage of (Mg0.92, Fe0.08)O (Mw) + SiO2(St) is significantly different from the experimental data, excluding the possibility of chemical decomposition of perovskite to oxides during the shock compression. The Grüneisen parameter γ obtained by fitting the experimental data can be expressed by γ = γ0 (ρ0/ρ)q, where γ0 = 1.84(2) and q = 1.69(3). Using the third‐order Birch‐Murnaghan finite strain equation of state, the shock experimental data yield a zero‐pressure bulk modulus K0s = 260.1(9) GPa and its pressure derivative K′0s = 4.18(4), with ρ0 = 4.19 g/cm3. A comparison of the experimental Hugoniot densities of perovskite with the PREM density profile prefers a perovskite‐dominant lower mantle model.
Aspects of soil moisture variability in the Washita '92 study region

The Washita '92 experiment, which took place in the Little Washita River watershed in Oklahoma, generated maps describing the volumetric surface soil moisture field during an 8-day drying period. The Little Washita is part of the Red River basin, a major tributary of the Lower Mississippi. A semivariogram analysis revealed that the surface soil moisture field of this 18 km × 25 km study region as a whole was spatially nonstationary and exhibited certain fractal characteristics. However, for smaller subareas within the study region, it was determined that the moisture field could be considered stationary for distances smaller than 5 km, with ranges of approximately 1 km over which surface soil moisture was spatially correlated. A semivariogram analysis for each of the individual soil types over the entire Washita '92 region revealed that surface soil moisture was stationary within each soil type, again with a range of correlation of approximately 1 km. This indicates that soil moisture variability is strongly affected by soil type.
Chronologic modeling of faulted and fractured reservoirs using geomechanically based restoration: Technique and industry applications

We have developed a geomechanically based restoration method to model reservoir deformation. The approach, founded on the finite-element method, simulates the physical behavior of the rock mass and considers heterogeneous material properties, bedding slip, and the mechanical interaction of faults. To demonstrate the method's potential, we analyze the deformation and fault growth in the hanging wall of a synsedimentary listric normal fault from a sand-box model, which provides an analog for evaluating complex faulted reservoirs. The numerical model results are then analyzed to investigate the chronology of faulting. The numerical model corresponds well to the physical model and provides additional insights about reservoir evolution and deformation. The approach is also tested on a natural example of folding using outcrop data to study contractional deformation. These examples illustrate how undetected faults and fractures, reservoir compartmentalization, hydrocarbon-migration pathways, and hydrocarbon traps can be understood in the context of tectonic processes and how this understanding can be exploited in decision making and reducing risk. We conclude that the geomechanically based restoration of faulted and fractured reservoirs has significant potential for industry applications compared to common geometric restoration techniques, which lack a mechanical basis.
Contrast in crustal structure across the Clipperton transform fault from travel time tomography

A three-dimensional (3-D) seismic refraction study of the Clipperton transform fault, northern East Pacific Rise, reveals anomalously low compressional velocities from the seafloor to the Moho. We attribute this low-velocity anomaly to intensive brittle deformation, caused by transpression across this active strike-slip plate boundary. The seismic velocity structure south of the Clipperton transform appears unaffected by these tectonic forces, but to the north, seismic velocities are reduced over 10 km outside the zone of sheared seafloor. This contrast in seismic velocity structure corresponds well with the differences in mid-ocean ridge morphology across the Clipperton transform. We conclude that the amount of fracturing of the upper crust, which largely controls seismic velocity variations, is strongly dependent on the shallow temperature structure at the ridge axis. Intermittent supply of magma to the shallow crust north of the Clipperton transform allows seawater to penetrate deeper, and the cooler crust is brittle to a greater depth than south of the transform, where a steady state magma lens is known to exist. The crustal thickness averages 5.7 km, only slightly thinner than normal for oceanic crust, and variations in Moho depth in excess of ∼0.3 km are not required by our data. The absence of large crustal thickness variations and the general similarity in seismic structure imply that a steady state magma lens is not required to form normal East Pacific Rise type crust. Perhaps a significant portion of the lower crust is accreted in situ from a patchwork of short-lived gabbro sills or from ductile flow from a basal magma chamber as has been postulated in some recent ophiolite studies.
Time Domain Reflectometry Measurements of Nitrate Transport in Manure‐Amended Soil

To obtain more detailed information about N processes in agricultural soils, nondestructive measurement techniques with high spatial and temporal resolution are needed. The ability of time domain reflectometry (TDR) in combination with small polysulfone hollow fiber (PHF) solution samplers to follow NO 3 - production and transport in soil fertilized with cattle slurry and exposed to different rainfall events was investigated. The experiments were conducted in minilysimeters using a coarse sandy soil and two different slurry application methods: (i) surface application followed by harrowing (homogenous incorporation) or (ii) direct injection (incorporation as a manure string). Comparison between soil-water electrical conductivity (EC w ) obtained with TDR and the sum of NO 3 - and Cl concentrations in the soil water measured with solution samplers showed a good agreement both with respect to concentration levels and temporal and spatial development. Except for an initial leaching of the natural ion content in the soil water when water application was started, NO 3 - released from the manure was the dominating anion in the soil water and changes in NO 3 - corresponded well to changes in EC w . Both slurry and water application strategy had a large effect on the temporal development in nitrification and NO 3 - leaching. In the case of homogeneously incorporated slurry and constant water application for 3 wk, NO 3 - formation and leaching started after 4 to 5 d, while it started after 9 to 10 d in the case of directly injected slurry. If water was applied only in the last (third) week to the directly injected slurry system, a large amount of the NH 4 + in the slurry was oxidized to NO 3 - before water application and subsequently leached. The TDR measurements of EC w with high spatial and temporal resolution combined with a few measurements of ion concentrations by PHF solution samplers is a new, valuable method for analyzing turnover and transport of nonconservative ions in soil.
Discharge Characteristics and Changes over the Ob River Watershed in Siberia

Abstract This study analyzes long-term (1936–90) monthly streamflow records for the major subbasins within the Ob River watershed in order to examine discharge changes induced by human activities (particularly reservoirs and agricultural activities) and natural variations. Changes in streamflow pattern were found to be different between the upper and lower parts of the Ob watershed. Over the upper Ob basin, streamflow decreases in summer months and increases in the winter season. The decreases in summer are mainly due to water uses along the river valley for agricultural and industrial purposes and to reservoir regulation to reduce the summer peak floods. The increases in winter streamflow are caused by reservoir impacts to release water for power generation over winter months. In the lower Ob regions, however, streamflow increased during midsummer and winter months and weakly decreased in autumn. These increases in summer flow are associated with increases in summer precipitation and winter snow cover ov.