White Sands National Monument Research Articles

The remarkable endemism of moths at White Sands National Monument in New Mexico, USA, with special emphasis on Gelechioidea (Lepidoptera)

The white sands formation, a snow-white gypsum dunes system, is the world's largest gypsum dune field. White Sands National Monument protects about 40% of the dunes; the dunes formation as it is known today was formed ca. 8,000 years BP. Prior to 8,000 years BP, the area covered by the dunes was a wet cool forest of the last glacial maximum in North America. The dunes were formed as a result of the hypsithermal, a warming and drying period which followed the most recent glacial maximum. The white sands formation is located in south central New Mexico in the Tularosa Basin of southwestern United States. A 10-year study of moths at the dunes was commissioned by the U. S. National Park Service in 2006. Almost immediately species new to science were detected. In the period of 6 years, 30 new species were discovered in the dunes. Several of the new species are white or very pale in color, and are endemic to the dunes. The focus of the 10 year project was modified to emphasize naming the undescribed species which helps the National Park Service catalog and manage the habitats. The data should encourage other researchers to explore the interactions of the animals with the plants and the harsh desert environment, to study DNA and evolution, and to study the rapid adaptation which seems to be occurring.

Numerical study of turbulent flow over complex aeolian dune fields: The White Sands National Monument

The structure and dynamics of fully developed turbulent flows responding to aeolian dune fields are studied using large-eddy simulation with an immersed boundary method. An aspect of particular importance in these flows is the downwind migration of coherent motions associated with Kelvin-Helmholtz instabilities that originate at the dune crests. These instabilities are responsible for enhanced downward transport of high-momentum fluid via the so-called turbulent sweep mechanism. However, the presence of such structures and their role in determining the bulk characteristics of fully developed dune field sublayer aerodynamics have received relatively limited attention. Moreover, many existing studies address mostly symmetric or mildly asymmetric dune forms. The White Sands National Monument is a field of aeolian gypsum sand dunes located in the Tularosa Basin in southern New Mexico. Aeolian processes at the site result in a complex, anisotropic dune field. In the dune field sublayer, the flow statistics resemble a mixing layer: At approximately the dune crest height, vertical profiles of streamwise velocity exhibit an inflection and turbulent Reynolds stresses are maximum; below this, the streamwise and vertical velocity fluctuations are positively and negatively skewed, respectively. We evaluate the spatial structure of Kelvin-Helmholtz instabilities present in the dune field sublayer (shear length L(s) and vortex spacing Λ(x)) and show that Λ(x)=m(dune)L(s), where m(dune)≈7.2 in the different sections considered (for turbulent mixing layers, 7<m<10 [M. M. Rogers and R. D. Moser, Phys. Fluids A 6, 903 (1994)]).

GOES-R Advanced Baseline Imager: spectral response functions and radiometric biases with the NPP Visible Infrared Imaging Radiometer Suite evaluated for desert calibration sites

The Advanced Baseline Imager (ABI), which will be launched in late 2015 on the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite R-series satellite, will be evaluated in terms of its data quality postlaunch through comparisons with other satellite sensors such as the recently launched Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership satellite. The ABI has completed much of its prelaunch characterization and its developers have generated and released its channel spectral response functions (response versus wavelength). Using these responses and constraining a radiative transfer model with ground reflectance, aerosol, and water vapor measurements, we simulate observed top of atmosphere (TOA) reflectances for analogous visible and near infrared channels of the VIIRS and ABI sensors at the Sonoran Desert and White Sands National Monument sites and calculate the radiometric biases and their uncertainties. We also calculate sensor TOA reflectances using aircraft hyperspectral data from the Airborne Visible/Infrared Imaging Spectrometer to validate the uncertainties in several of the ABI and VIIRS channels and discuss the potential for validating the others. Once on-orbit, calibration scientists can use these biases to ensure ABI data quality and consistency to support the numerical weather prediction community and other data users. They can also use the results for ABI or VIIRS anomaly detection and resolution.

Microbial Nitrogen and Sulfur Cycles at the Gypsum Dunes of White Sands National Monument, New Mexico

The White Sands National Monument from New Mexico (U.S.A) contains one of the largest known gypsum dune fields with unique, rapidly migrating, arid, evaporitic habitats. Deposits from dune sides and interdune areas were collected in order to determine the characteristics of microbial habitat and communities through mineral assemblages, microbial pigments along with investigations of nitrogen and sulfur cycles. The most abundant pigments, scytonemin and carotenoids, were common UV protective pigments. Predominance of nitrite and nitrate over ammonium nitrogen (2.16: 1) implies that nitrification processes might be important in this ecosystem. Ammonium oxidizers from groups of β-, γ-proteobacteria and archaea were detected in all deposits, thereby indicating microbial involvement in nitrification. Additionally, denitrifying organisms with nirS and nirK genes were also present in most of the analyzed samples. The presence of trace carbonate mineral phases in association with biofilm implies possible microbial sulfate reduction. Microbes with metabolic abilities for sulfur cycling (i.e., dissimilatory sulfite reducers, purple sulfur bacteria, green sulfur and non-sulfur bacteria, and organisms with the APS enzyme) were identified in all samples. These particular organisms have the ability to reduce sulfate and to re-oxidize reduced sulfur compounds back to sulfate.

The Lepidoptera of White Sands National Monument 5: Two new species of Cochylini (Lepidoptera, Tortricidae, Tortricinae)

In 2006, 10-year studies of the moths in two park units of the U.S. National Park Service in southern New Mexico were initiated: White Sands National Monument in Otero County, New Mexico, USA; and Carlsbad Caverns National Park, in Eddy County, New Mexico, USA. Two new species of Cochylini, Eugnosta brownana Metzler &amp; Forbes and Cochylis yinyangana Metzler, are described. Adults and male and female genitalia of both species are illustrated.

Plant tolerance of a high calcium environment via foliar partitioning and sequestration

Our purpose in this study was to assess whether a range of plant species tolerate a very high-calcium (Ca) environment by chemically sequestering excess Ca in a physiologically unavailable form, thus maintaining labile foliar Ca at appropriately low levels. Calcium concentration within the cytoplasm of cells must be maintained at low levels to avoid toxicity, and to allow for Ca-based cellular signaling in response to numerous environmental cues. We assessed Ca partitioning and sequestration in foliage from six plant species growing at White Sands National Monument, a site with primarily gypsum (calcium sulfate) substrate, which supplies very high plant-available Ca in the soils. Chemical components of foliar Ca were separated by sequential acidic extractions and assessed using a colorimetric Ca analysis. We found substantial variability among species in their uptake and retention of Ca, especially in their ability to sequester the Ca they absorb. Of the six species we evaluated, four sequester large portions (40-90 percent) of their foliar Ca in a chemically-unavailable form, and one of these appears to substantially limit Ca uptake. The other two species maintain over 90 percent of their foliar Ca in labile forms, which may enable exudation of excess Ca via salt glands. This work provides new insights into the physiology of foliar Ca tolerance in plants growing in high-Ca conditions, as well as the physiological and ecological processes that occur in the unique ecosystems found at White Sands National Monument.

Contrasting effects of microbiotic crusts on runoff in desert surfaces

Microbiotic crusts (MCs) play an important role in surface hydrology by altering runoff yield. In order to study the crust's role on water redistribution, rainfall and runoff were measured during 1998–2000 at three sites within the northern Chihuahuan Desert, New Mexico, USA: the Sevilleta National Wildlife Refuge (SEV), the White Sands National Monument (WS), and the Jornada Experimental Range (JER). Whereas quartz and gypsum sand characterize the SEV and WS sites, respectively, both of which have high infiltration rates, silty alluvial deposits characterize the JER site. Runoff was measured in four pairs of 1.8–6.4 m 2 plots having MCs, one of which was scalped in each pair. No runoff was generated at WS, whether on the crusted or the scalped plots. Runoff was however generated at SEV and JER, being higher on the crusted plots at SEV and lower on the JER plots. The results were explained by the combined effect of (a) parent material and (b) the crust properties, such as species composition, microrelief (surface roughness) and exopolysaccharide (EPS) content (reflected in the ratio of carbohydrates to chlorophyll). Whereas the effective rainfall, the fines and the EPS content were found to explain runoff initiation, the effective rainfall and the crust microrelief were found to explain the amount of runoff at SEV and JER where runoff generation took place. The findings attest to the fundamental role of the parent material and the crust's species composition and properties on runoff and hence to the complex interactions and the variable effects that MCs have on dryland hydrology.

The Lepidoptera of White Sands National Monument, Otero County, New Mexico, USA 3. A new species of Aleptina Dyar, 1902 (Lepidoptera, Noctuidae, Amphipyrinae, Psaphidini)

In 2006 the US National Park Service initiated a long-term study of the Lepidoptera at White Sands National Monument, Otero County, New Mexico. Aleptina arenaria sp. n., described here, was discovered in 2008, the second year of the study. The adult moths and male and female genitalia are illustrated.

The Lepidoptera of White Sands National Monument, Otero County, New Mexico, USA 4. A new species of Schinia Hübner, 1818 (Lepidoptera, Noctuidae, Heliothinae)

In 2006 the U.S. National Park Service initiated a long term study of the Lepidoptera at White Sands National Monument, Otero County, New Mexico. Schinia poguei sp. n., described here, was discovered in 2007, the second year of the study. The male and female adult moths and genitalia are illustrated.

The Lepidoptera of White Sands National Monument, Otero County, New Mexico, USA 2. Rediscovery and description of Sparkia immacula (Grote, 1883) (Noctuidae, Noctuinae, Hadenini)

In 2006 the U.S. National Park Service initiated a long term study of the Lepidoptera at White Sands National Monument, Otero County, New Mexico. Sparkia immacula (Grote, 1883), previously known only from historical specimens collected in Arizona and New Mexico, was discovered in the Monument in 2007 during the second year of the study. The adult moths and male and female genitalia are illustrated for the first time.

Sorting out abrasion in a gypsum dune field

Grain size distributions in eolian settings are the result of both sorting and abrasion of grains by saltation. The two are tightly coupled because mobility of particles determines abrasion rate, while abrasion affects the mobility of particles by changing their mass and shape; few field studies have examined this quantitatively. We measured grain size and shape over a 9 km transect downwind of a line sediment source at White Sands National Monument, a gypsum dune field. The sediment source is composed of rodlike (elongate), coarse particles whose shapes appear to reflect the crystalline structure of gypsum. Dispersion in grain size decreases rapidly from the source. Coarse particles gradually become less elongate, while an enrichment of smaller, more elongate grains is observed along the transect. Transport calculations confirm that White Sands is a threshold sand sea in which (1) the predominant particle diameter reflects grains transported in saltation under the dune‐forming wind velocity and (2) smaller, elongate grains move in suspension under this dominant wind. Size‐selective transport explains first‐order trends in grain size; however, abrasion changes the shape of saltating grains and produces elongate, smaller grains that are spallation and breaking products of larger particles. Both shape and size changes saturate 5–6 km downwind of the source. As large particles become more equant, abrasion rates slow down because protruding regions have been removed. Such asymptotic behavior of shape and abrasion rate has been observed in theory and experiment and is likely a generic result of the abrasion process in any environment.

Analysis of ASTER Emissivity Product Over an Arid Area in Southern New Mexico, USA

The accuracy of thermal infrared emissivities derived from Advanced Spaceborne Thermal Emission and Reflectance radiometer (ASTER) was assessed in an arid area in southern New Mexico, which includes the White Sands National Monument (WSNM) during 2006-2008. ASTER emissivities retrieved by the temperature and emissivity separation (TES) algorithm were directly compared with laboratory measurements of samples from WSNM. Good agreement was found for the high spectral contrast of gypsum and for the low spectral contrast of water bodies. Furthermore, the day/night consistency of ASTER emissivities was checked, and day/night emissivity differences lower than ±0.013 were observed. However, unexpected emissivity values larger than unity were retrieved by ASTER/TES at 8-9 μm , mainly concentrated over lava flow surfaces. The thermal infrared radiance image data with 90-m spatial resolution was resized to 180 m for the analysis in this paper to avoid misregistration problems due to terrain topography. Emissivity temporal variations were analyzed and attributed, in some cases, to the soil moisture variations. This was particularly noted after periods of high precipitation which occurred in August 2006. The results presented here show the high emissivity accuracy achievable with ASTER data in ideal atmospheric conditions and discuss some problems which should be considered in the future, as the retrieval of overestimated emissivity values.

Spiders of the Chihuahuan Desert of Southern New Mexico and Western Texas

Abstract Little information is available on spiders in the Chihuahuan Desert. In the Jornada del Muerto of southern New Mexico, we collected ca. 120 species of spiders in the past 30 years. We report four state records and five potential undescribed species. A comparison of our list of species with those from three other areas in the Chihuahuan Desert (White Sands National Monument and vicinity and Valley of Fires near Carrizozo and vicinity, both in New Mexico, and an area near Big Bend, Texas) revealed low overlap, indicating that the regional spider fauna is still not fully known. Baseline knowledge of the spider fauna from several sites could serve as a criterion for assessing climatic change.

Origin and evolution of polygonal cracks in hydrous sulphate sands, White Sands National Monument, New Mexico

AbstractThe nucleation and propagation of polygonal cracks in hydrous sulphate dunes at White Sands National Monument, New Mexico, are affected by water availability, transport through the sand and exchange with the atmosphere. These gypsum sands are cohesive enough to crack due to capillary forces and gypsum cements formed during evaporation. Surface cracks form five‐sided polygons with a variety of triple‐junction angles. Cracks extend down to variable depths and polygons increase in size with depth, showing a maturation similar to experimentally produced polygonal columns in drying corn starch. Results from two years of monitoring crack geometries, temperature and humidity demonstrate that cracks form when water is lost to the atmosphere through the transport of water vapour. Subsurface relative humidity below 5 to 10 cm is almost always maintained at 100% by the evaporation and condensation of water in thin films on grains. The amplitude of daily temperature and thus absolute humidity changes decreases with depth, consistent with lower evaporation and condensation rates with increasing depth. Changes in absolute humidity and the contrast between humidity in pore spaces versus the overlying atmosphere result in significant water loss from the dunes except during times of precipitation and frost/dew condensation. This water loss allows cracks to nucleate and propagate into the dunes. This study hypothesizes that crack tips propagate into sand to the depth at which thin films of water on grains are drying, and that this depth varies from the surface of the dune during precipitation events to depths greater than 45 cm when dunes are drier.

High albedo dune features suggest past dune migration and possible geochemical cementation of aeolian sediments on Mars

High albedo features are identified in association with barchan dunes in an equatorial inter-crater dune field on Mars using images from the MRO mission. This paper describes the morphometric properties of these features and their association with the present barchan dune field. We propose that these features are cemented aeolian deposits that form at the foot of the dune avalanche face. A possible terrestrial analog exists at White Sands National Monument, in south-central New Mexico, USA. The presence of these features suggests past episodes of dune migration in inter-crater dunefields and liquid water in the near sub-surface in sufficient quantity to cause the cementation of aeolian dune sediment.

Origin of coarsely crystalline gypsum domes in a saline playa environment at the White Sands National Monument, New Mexico

Dome‐like structures up to 3 m in height, composed predominantly of coarse crystals of selenite gypsum, occur on the surface of Alkali Flat, a saline playa lake in White Sands National Monument, New Mexico. The structures were investigated using field observations, aerial images, and geochemical methods. The domes are inferred to be remnants of lake sediments that have been preserved from Holocene eolian erosion due to higher cementation resulting from crystallization of large gypsum (selenite) crystals in the playa's clay‐rich sediments. Low δ2H values of the selenite, from −90 to −69 ‰, suggest precipitation from saturated solutions associated with groundwater seepage in the playa related to the upward flows of groundwater, primarily fed by meteoric water rather than the evaporation of the playa water. Values of δ34S for selenite range from 12.1 to 13.8 ‰ (median 13.0 ‰) and are notably higher than the dissolved sulfate in the modern groundwater system that has δ34S values from 10.2 to 11.8 ‰ (median 11.4 ‰). The two main regional sources of sulfate are Middle Permian evaporites with median δ34S values of 12.0 ‰ and Lower Permian evaporites with median δ34S values of 13.0 ‰. The δ34S values measured in domes suggest their formation during a period of time when groundwater seepage might have been dominated by deeply circulating water that interacted with Lower Permian evaporites buried in the basin center. The apparent alignments of domes suggest that past groundwater seepage was controlled by fractures beneath Alkali Flat which are associated with a regional fault system in the area.

The Lepidoptera of White Sands National Monument, Otero County, New Mexico, USA 1. Two new species of Noctuidae (Lepidoptera, Noctuinae, Agrotini)

The white gypsum dune ecosystem in the Tularosa Basin in south central New Mexico is the largest gypsum dune field on earth, covering 712.25 km2. White Sands National Monument in Otero County, New Mexico, protects approximately 40%, 297.85 km2, of this dune field. In 2006 the US National Park Service initiated a long term study of the Lepidoptera at White Sands National Monument, resulting in the discovery of two new species, Euxoa lafontainei Metzler &amp; Forbes, n. sp. and Protogygia whitesandsensis Metzler &amp; Forbes, n. sp. described herein. Adult moths and male and female genitalia are illustrated for Euxoa lafontainei, and adults and male genitalia are illustrated for Protogygia whitesandsensis and its relatives.

Comparison of Thermal Infrared Emissivities Retrieved With the Two-Lid Box and the TES Methods With Laboratory Spectra

Knowledge of surface emissivity in the thermal infrared (TIR) region is critical for determining the land surface temperature (LST) from remote-sensing measurements. If emissivity is not well determined, it can cause a significant systematic error in obtaining the LST. The main aim of this paper is to compare different methods for measuring accurate land surface emissivity in the field, namely, the box method and the temperature and emissivity separation (TES) algorithm. Field emissivities were compared with soil spectra from laboratory measurements. Emissivities were measured for the bands of a multispectral radiometer CE312-2 with effective wavelengths at 8.4, 8.7, 9.1, 10.6, and 11.3 mum, similar to the Advanced Spaceborne Thermal Emission and Reflection Radiometer TIR bands, and a wide channel 8-13 mum. The measurements were made at two sites in New Mexico: the White Sands National Monument and an open shrub land in the Jornada Experimental Range. The measurements show that for both sites the emissivities derived with the Box method agree with those derived with the TES algorithm for the 10.6 and 11.3 mum bands. However, the emissivities for the shorter wavelength bands are higher when derived with the Box method than those with the TES algorithm, with differences ranging from 2% to 7%. The field emissivities agree within 2% with the laboratory spectrum for the 8-13-, 11.3-, and 10.6-mum bands. However, the field and laboratory measurements in general differ from 2.4% to 9% for the shorter wavelength bands, with the larger value most likely caused by variations in soil moisture.

Groundwater salinity as a control on development of eolian landscape: An example from the White Sands of New Mexico

The White Sands of southern New Mexico form the largest field of gypsum dunes in the world. The juxtaposition of several different types of dunes within the field has long been recognized and has generally been attributed to changes in the rate of sand transport across the dune field. However, Steven Fryberger [Fryberger, S.G., 2003. Geology of White Sands National Monument, web page www2.nature.nps.gov/geology/parks/whsa/] recently hypothesized, however, that a primary control is groundwater salinity. The White Sands dune field is underlain by saline waters. Fryberger proposed that parabolic dunes could form in topographic highs that accumulated a lens of fresher water derived from precipitation. Water with lower salinity allowed vegetation to grow, and stabilized the sand except for the active noses of the parabolic dunes. This study is a test of that hypothesis. A study transect was established across the boundary between parabolic and barchan dunes. Groundwater and soil at six sites were sampled during December, 2004 and March, May, and June of 2005. Two sites were established in the parabolic field, two in the barchans, and two in the transition zone between them. Groundwater was found to be three times more saline in the barchan area. Conductivity and chloride decreased across the transition zone. A GPS topographic survey revealed two abrupt topographic steps, one at the boundary between the barchans and the transition zone and a second at the edge of the parabolic field. A second, larger topographic step was found outside the study area defining a higher parabolic dune field. These data indicate that Fryberger's (2003) hypothesis is correct and groundwater is controlling the dune field morphology. The dune field did not begin to form until the Mid-Holocene (6500 years ago). A compilation of dates shows that the parabolic dune field has probably been stable for the last 3500 years. In contrast, the barchan area has been recently deflated and exposed 2000 year old sediment near the surface.

Spatial grain size sorting in eolian ripples and estimation of wind conditions on planetary surfaces: Application to Meridiani Planum, Mars

The landscape seen by the Mars Exploration Rover (MER) Opportunity at Meridiani Planum is dominated by eolian (wind‐blown) ripples with concentrated surface lags of hematitic spherules and fragments. These ripples exhibit profound spatial grain size sorting, with well‐sorted coarse‐grained crests and poorly sorted, generally finer‐grained troughs. These ripples were the most common bed form encountered by Opportunity in its traverse from Eagle Crater to Endurance Crater. Field measurements from White Sands National Monument, New Mexico, show that such coarse‐grained ripples form by the different transport modes of coarse‐ and fine‐grain fractions. On the basis of our field study, and simple theoretical and experimental considerations, we show how surface deposits of coarse‐grained ripples can be used to place tight constraints on formative wind conditions on planetary surfaces. Activation of Meridiani Planum coarse‐grained ripples requires a wind velocity of 70 m/s (at a reference elevation of 1 m above the bed). From images by the Mars Orbiter Camera (MOC) of reversing dust streaks, we estimate that modern surface winds reach a velocity of at least 40 m/s and hence may occasionally activate these ripples. The presence of hematite at Meridiani Planum is ultimately related to formation of concretions during aqueous diagenesis in groundwater environments; however, the eolian concentration of these durable particles may have led to the recognition from orbit of this environmentally significant landing site.