نتایج جستجو برای: playa
تعداد نتایج: 939 فیلتر نتایج به سال:
the Siahkuh playa is one of the greatest deserts in Yu.d province and is located in the north-north eastern of Ardakan city. In playa regions, different sub-environments with different mineral potentials can be recognized. In Siahkuh playa, various evaporite minerals such as gypsum in different form (sugery, nodular and euhedral crystals), halite (fibrous, cylindrical, hopper-shaped crysta...
Expansive playa-lake systems situated in high-altitude piggyback basins are important and conspicuous components of both modern and ancient cordilleran orogenic systems. Extant playa lakes provide vital habitat for numerous endemic species, whereas sediments from these deposystems may record signals of climate change or develop natural resources over geological time. Laguna de los Pozuelos (Nor...
Although amphibians are the dominant vertebrate inhabiting playa wetlands during spring and summer in the Southern Great Plains, little is known about their diet and role in playa trophic structure. Because new metamorphs are more numerous than other terrestrial life stages of amphibians, we describe the diets of recently (,2 weeks) metamorphosed Great Plains toad (Bufo cognatus), barred tiger ...
Sedimentation (primarily from human land use) is a major threat to runoff-fed wetlands of the Great Plains of North America (playas), but it is unknown how many playas are turbid, how prevalence of turbidity has changed over time, and how turbidity is related to surrounding land use. We used remotely sensed imagery to assess sedimentation in the waters of over 7700 playa basins in Texas on four...
Ground based in-situ measurements of carbon dioxide (CO2) and methane (CH4) at the dry lakebed at Railroad Valley (RRV) playa, Nevada, USA (38°30.234′ N, 115°41.604′ W, elevation 1437 m) were conducted over a five day period from 20–25 June 2010. The playa is a flat, desert site with virtually no vegetation, an overall size of 15 km × 15 km and is approximately 110 km south-west of the nearest ...
The resource island hypothesis predicts that soil resources such as nitrogen, phosphorus, and water will be distributed evenly in grasslands but have a patchy distribution focused around plants in shrublands. This hypothesis predicts that microorganism numbers will follow resources and be (i) evenly distributed in grasslands, (ii) concentrated around individual plants in shrublands, and (iii) h...
There are 25,000–30,000 playa wetlands in the intensively cultivated Southern Great Plains of the United States. Knowledge of area and watershed influences on wetland flora are needed to guide their conservation. We surveyed plant-community composition in 224 playas over 360,000 km 2 and examined the relationships of species richness and diversity (Shannon’s) to playa area and watershed disturb...
Bioerosion of branched corals was assessed in a fringing reef (Playa Blanca) and a patch reef (Gorgonilla) of Gorgona Island in the tropical eastern Pacific. Cylinder-shaped experimental units (EUs), made from branches of Pocillopora spp., were set 50 cm above the sea bottom for 6, 12 and 18 mo in Playa Blanca (4 zones: Back Reef, Reef-Flat Crest, Reef Front and Reef Slope) and the Gorgonilla p...
Saline playas in north-western Nevada, U.S.A., remnants of pluvial periods of the Pleistocene, represent a tremendous source of unconsolidated sediments available for aeolian transport. This study investigated the transport of aqueous-soluble solutes in dust from July 1994 through June 1996 along a transect from a barren salt-encrusted playa surface (elevation"1224 m), to a former pluvial lake ...
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