Valley Of Mexico Research Articles

Burial and thermal history modeling of basins in convergent oblique-slip mobile zones: A case study of the Ardmore Basin, southern Oklahoma

The burial and thermal history of sedimentary basins within oblique-slip mobile zones are unique and multifaceted, with irregular periods of subsidence that are closely related to compressional and shear stress. Modern basin modeling techniques can constrain the timing of tectonic events and thermal history as well as determine rates and magnitudes of basin subsidence, which in turn, helps guide exploration for hydrocarbons. The work presented here is the first modern basin modeling effort in the Ardmore Basin in southern Oklahoma. The study uses 12 one-dimensional burial history models to evaluate the thermal maturity of the Late Devonian (Famennian)–Early Mississippian (Tournaisian) Woodford Shale and the Early–Late Mississippian (Tournaisian–Serpukhovian) Caney Shale hydrocarbon source rocks. All models display a similar tectonic evolution with subsidence during and following Cambrian Iapetan rifting, tectonic stability during a Silurian–Late Mississippian passive margin phase, Pennsylvanian synorogenic subsidence, Permian post-orogenic subsidence, Late Permian–Early Cretaceous regional uplift and unroofing, and Early Cretaceous–Paleogene subsidence of the Gulf of Mexico Basin. Episodic Pennsylvanian subsidence appears to have been synchronous with sequential uplift of the Wichita Uplift and the Arbuckle Uplift in response to major left-lateral transpression. Rapid and high magnitude Late Mississippian–Permian subsidence (>250 m/m.y.; 820 ft/m.y. in basin synclines) suggests the Ardmore Basin functioned episodically as an elevator basin, which is typical of sedimentary basins in oblique-slip mobile zones. The Devonian–Mississippian shale section has a broad range of thermal maturity (vitrinite reflectance, 0.40–2.00% Ro), which is strongly dependent on structural position. Isoreflectance lines are subhorizontal and cross-cut structure, indicating post-kinematic thermal maturation in which strata are thermally immature in uplifts and thermally overmature in the deepest synclines. The post-kinematic pattern is a product of a rapid, early phase of synkinematic thermal maturation that has been obscured by a prolonged period of post-kinematic thermal maturation. Variations in basal heat flow, structural history, and general variability of hydrocarbon source rock organic composition, particularly at low thermal maturity levels, have resulted in a modest degree of scatter in the vitrinite reflectance-depth data.

Virulence and Antimicrobial Resistance Profiles of Shiga Toxin-Producing Escherichia coli from River Water and Farm Animal Feces near an Agricultural Region in Northwestern Mexico

Shiga toxin-producing Escherichia coli (STEC) are zoonotic enteric pathogens linked to human gastroenteritis worldwide. To aid the development of pathogen control efforts, the present study characterized the genotypic diversity and pathogenic potential of STEC recovered from sources near agricultural fields in Northwest Mexico. Samples were collected from irrigation river water and domestic animal feces in farms proximal to agricultural fields and were subjected to enrichment followed by immunomagnetic separation and plating on selective media for the recovery of the STEC isolates. Comparative genomic analyses indicated that the recovered STEC with the clinically relevant serotypes O157:H7, O8:H19, and O113:H21 had virulence genes repertoires associated with host cell adherence, iron uptake and effector protein secretion. Subsequent phenotypic characterization revealed multidrug resistance against aminoglycoside, carbapenem, cephalosporin, fluoroquinolone, penicillin, phenicol, and tetracycline, highlighting the need for improved surveillance on the use of antimicrobials. The present study indicated for the first time that river water in the agricultural Culiacan Valley in Mexico is a relevant key route of transmission for STEC O157 and non-O157 with a virulence potential. In addition, feces from domestic farm animals near surface waterways can act as potential point sources of contamination and transport of diverse STEC with clinically relevant genotypes.

Evidencia de variación morfológica en una población de refugio aislada del cachorrito de Sonoyta (Cyprinodon eremus) (Teleostei: Cyprinodontidae)

The Sonoyta pupfish (Cyprinodon eremus) is an endangered species endemic to the Sonoyta River basin in northwestern Mexico and southwestern United States. To assist the conservation efforts for this species in Mexico, a refuge population was established in an artificial pond in 1988 at Centro Ecológico de Sonora in Hermosillo, Sonora by translocating individuals from the Sonoyta River population. We used multivariate morphometric methods to delineate body shape variations in the refuge population after 29 years of isolation in comparison with wild individuals collected from the same sample. Significant variations were observed in the body shape between the refuge and wild populations. These variations are potentially attributable to different environmental conditions that influenced the refuge and wild populations.

Evaluation of Machine Learning Models for Ozone Concentration Forecasting in the Metropolitan Valley of Mexico

In large and densely populated cities, the concentration of pollutants such as ozone and its dispersion is related to effects on people’s health; therefore, its forecast is of great importance to the government and the population. Given the increased computing capacity that allows for processing massive amounts of data, the use of machine learning (ML) as a tool for air quality analysis and forecasting has gotten a significant boost. This research focuses on evaluating different models, such as Random Forest (RF), Support Vector Regression (SVR), and Gradient Boosting (GB), to forecast ozone (O3) concentration 24 h in advance, using data from the Mexico City Atmospheric Monitoring System using meteorological variables that influence the phenomenon of ozone dispersion and formation.

Evidence of SARS-CoV-2 infection in companion animals from owners who tested positive for COVID-19 in the Valley of Mexico

BackgroundLittle is known about the companion animals which tested positive in Mexico for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. Due to this, it is that we have documented the infection of companion animals, via an exploratory approach in two localities of the Valley of Mexico, in which the companion animal owners tested positive for COVID-19.MethodsOropharyngeal and nasopharyngeal swabs were collected from 21 companion animals. Also, a Reverse-Transcription Quantitative Polymerase Chain Reaction was used to test five probes in three SARS-CoV-2 genes. More than one-third (5/14) of these samples were positive for SARS CoV-2 corresponding to dogs.ResultsThis research translates into the first available report on companion animals with SARS-CoV-2 infection in the most populated area of Mexico. Samples were added chronologically to previous reports prepared in other areas of the country, from February through November 2022.ConclusionAlthough SARS-CoV-2 infection in dogs is not as common as in other animals, our results suggest that it can be transmitted to dogs by their owners to a greater extent than previously reported.

Christian allegory on the northern frontier of New Spain: González de Eslava’s Coloquio quinto

ABSTRACT Fernán González de Eslava’s fifth Coloquio espiritual y sacramental is a Christian allegorical drama from New Spain of the 1570s. It concerns Spanish attempts to ‘pacify’ the Gran Chichimeca, a contested desert frontier to the north of the Valley of Mexico. The antagonist of this play is a Chichimeca warrior, who challenges military and missionary attempts to conquer and convert. González de Eslava’s allegory vilifies this nomadic native warrior, casting him as the very figure of sin. This piece portrays a fierce Indigenous alterity in order to justify Spanish incursions into native lands and promote a Christianizing agenda. Remarkably, the playwright portrays Chichimeca territory with reference to a major foundational narrative of central Mexican peoples. He invokes the storied trajectory of ancestral migrants who departed from legendary sites of origin in the north, and journeyed southward into the Mexican Basin, where they settled. However, the allegorical drama reconfigures this southward path, and in the place of a central Mexican foundational narrative, González de Eslava asserts a Christian narrative and symbolic system.

Surface deposits and intracellular concentration of atmospheric particles in foliage of urban forests in the Valley of Mexico

Foliage of urban vegetation can be used as a bioindicator of air pollution, including heavy metals. We measured surface and intracellular concentration of copper, zinc, lead, nickel, chromium, cobalt and cadmium in Fraxinus uhdei leaves from three urban forests of the Metropolitan Area of the Valley of Mexico (ZMVM) during the four seasons of the year and assessed its correlation with distance to nearest roads; we also compared obtained concentrations with the local atmospheric monitoring network. We performed a two-factor experimental design: factor forest with three levels (Naucalli Park, Forests and Tlalpan) and factor season with four levels, to analyze spatio-temporal differences in heavy metal concentration. Fifteen Fraxinus uhdei trees were selected per site and a foliage sample was taken. A t-test was applied for comparisons between deposits, while an analysis of variance and Tukey's test was used to compare between seasons and forest. Relationship between surface concentrations and distance to the streets surrounding the forests was obtained using the Stepwise method. The obtained results indicate that there are higher concentrations superficially than intracellular in all metals analyzed, except for nickel. Copper was highest in Parque Naucalli, lead, nickel, chromium and cadmium in Bosques Chapultepec and zinc in Bosques Tlalpan. Highest concentrations occurred in summer for copper, zinc, nickel and chromium and in winter for lead and cadmium. We found that the surface concentration of copper, zinc, lead and cadmium in the foliage is higher when trees are closer to avenues. Our research indicates that trees can be valuable bioindicators for air pollution, as they not only mirror the diverse pollution sources but also provide insights into pollutant exposure based on proximity to those sources.

Reconstructing the Zama (Mexico) discovery source to sink palaeogeography, Part II: Sediment routing from the Late Miocene shelf‐margin to deepwater basin

AbstractThe Late Miocene source terrane tectonic history in the southern Gulf of Mexico Basin, as informed by detrital zircon geothermochronology data, supports a detailed regional palaeogeographic reconstruction from palaeoshoreline to the deepwater Zama minibasin of the Sureste salt basin. Seismic mapping points to a trio of pathways that converge upon two entry points into the Zama minibasin, illuminating how sediment gravity flows transit a complex seascape defined by shallow salt bodies. Consideration of empirical scaling relationships within and between segments of this sediment dispersal system allows for testable predictions of Upper Miocene submarine fan‐runout lengths over basin exploration areas. Distances from the reconstructed shelf‐margin to the Zama wells vary around 100 km, an increase of 20% over a straight‐line distance as flows likely navigated around extant salt stocks, walls and sheets. This 100‐km fan length is about 40% of the reconstructed minimum palaeo‐river length, within predicted ranges for smaller source‐to‐sink systems in tectonically active areas (25 to 50%). The estimated fan‐runout distance can be extended even further basinwards, considering the contemporaneous passage of the mobile Chortis block along the Tonala shear zone, expanding the Palaeo‐Rio Grijalva drainage network during the Tortonian. These Late Miocene deepwater systems linked to the Palaeo‐Rio Grijalva differ substantially from onshore Mexico‐sourced turbidity flows feeding into the axis of the north‐trending Veracruz Trough. Textural data from wells here suggests these systems were less effective at larger grain transport and sorting. Local (intrabasinal) variations are also evident within the Zama minibasin, as well data (image logs and cores) indicate that axially oriented sediment gravity flows involved fewer high‐density turbidities, depositing lower net‐to‐gross sandstones and thicker shales than those flowing transverse to the basin axis from a southeastern basin entry point. These interpretations will guide both local exploitation of these economic resources and could also support future exploration for analogous salt‐influenced deepwater reservoir systems in the Sureste basin and globally.

Orange Ware production and exchange in formative central Mexico as an index of regionalization of pottery styles

Ceramics present archaeologists with a medium to explore the range and intensity of interactions across space and over time. Style associations between regions indicate, at a minimum, communication, trade, or possibly migration coupled with an open disposition with respect to social identity formation. Conversely, style boundaries may develop for a variety of reasons, including but not limited to geographically restricted levels of interaction and more insular attitudes towards outgroups. Gordon Willey (1991) drew these alternatives into a cyclical model, shifting between broad style horizons and regionalized traditions. Early Mesoamerican style horizons as expressed through ceramics developed along broad networks of open cultural exchanges during the Early and Middle Formative periods. By the Late Formative, however, Mesoamerica fragmented into distinctive regionalized ceramic traditions. We provide a small-scale view of this process at the end of the Middle Formative using compositional sourcing to identify a divergence in the ceramic traditions of two neighboring regions: the Basin of Mexico and Morelos. During this timeframe, groups across lowland Mesoamerica developed an Orange Ware tradition that extended into Morelos. As revealed through neutron activation analysis (NAA) and petrography, the majority of orange/yellow Lacquer Ware found in the Basin of Mexico was imported from Morelos during the late Middle Formative, but Basin potters never adopted Orange Wares into their own style repertoires. The Morelos Orange Ware tradition is the first ceramic style in a long history of interaction between the two regions that was not matched by parallel developments in both regions, thus serving as a reference to an inflection point in the cycling between horizontal integration and regional differentiation that Willey hypothesized. This process continued into the Late Formative when Basin groups realigned with groups to the northwest through the adoption of Chupícuaro ceramic traits.

Urban Political Ecology in Mexico: Metabolism, conflicts, and the need for transformational pathways in the Valley of Mexico, Guadalajara, and Monterrey

This article analyzes urban socio-ecological conflicts in the Mexican metropolitan areas of the Valley of Mexico, Guadalajara and Monterrey from an Urban Political Ecology (UPE) approach. We identify the main triggers of such urban socio-ecological conflicts and the causal links between actors, resources and spaces which make up the uneven production of urban space. This focus includes unequal access to resources, uneven distribution of environmental impacts, and the rise of contestation. We outline UPE theoretically and conceptually, and delineate what is meant by urban socio-ecological conflict. UPE is then contextualized within Mexico's contemporary urbanization process as a prelude for characterizing case studies (including their metabolic profiles) and the analysis of prevailing socio-ecological conflicts. For the latter, we identify the main urban conflicts in the years 2012 and 2022, highlighting some of the main characteristics, similarities, and discontinuities across three metropolitan areas. In the face of an increasing metabolism of contemporary urbanization, we conclude with a brief consideration of the potential role of socio-ecological conflicts for enabling alternative forms of urban space production, particularly through the agency of social movements, including their capacity to propose and build "urban spaces of hope."

Identification of recharge processes and mixing patterns by using CFC's and isotopic multi-tracing (δ18O, δ2H) of groundwater in a stratified volcanoclastic aquifer of the semiarid Amazcala Basin in Central Mexico

Understanding groundwater flow is essential for quantifying recharge and identifying relevant processes in an aquifer. Hydrogeochemical models have proven to be successful in identifying origin and processes during water recharge. We integrated the hydrogeochemistry, environmental isotopes and CFC technique to develop a conceptual and a groundwater mixing model of the Amazcala aquifer in Central Mexico. Results demonstrate that groundwater recharge consists of local meteoric recharge and a regional geothermal input. The local resident groundwater component represents the primary source of groundwater contributing with an average of 56% (σ = 0.07). The second crucial component of groundwater is the contribution of the local meteoric component contribution with averages to 23% (σ = 0.05). The third component is the regional geothermal component, which on average contributes to 21% (σ = 0.03). Regional geothermal influence has been reported in several aquifers in volcanic regions. This geothermal input influences volcanic aquifers located in the Trans-Mexican Volcanic Belt and should be considered in the water balance budget. Excessive groundwater extraction raises the vulnerability of the aquifer to natural and/or anthropogenic pollution, affecting the quality of water. Understanding the hydrogeological system offers a useful framework for developing and executing Managed Aquifer Recharge strategies (MAR).

Organic richness and source rock potential of the La Peña Formation in the Sabinas and Piedras Negras basins, NE of Mexico

This paper investigates the petroleum generation potential of the Lower Cretaceous organic-rich rocks of the La Peña Formation in the Sabinas and Piedras Negras Basin (SB-PNB) of northeastern Mexico. In order to provide insights into the source rock potential of this unit, a total of 25 cutting samples collected from 15 wells at different stratigraphic intervals along the study area were analysed using Rock-Eval Pyrolysis technique. The analytical results revealed that all the analysed samples can be described as hydrogen-poor organic matter with HI <200 mg HC/g TOC. The organic richness indicates a poor to excellent Total Organic Carbon content suggesting that existed different conditions during the deposition and burial of this unit, causing variable organic matter production and preservation. Also, the results revealed a variation in the kerogen types that may be attributed to the relative stratigraphic positions of the selected samples in the wells.
 With respect to the organic matter thermal maturity, given by the geographical distribution of the Tmax values, the mature and overmature zone (435–508 °C) correspond to the Sabinas basin (SB).
 Overall, these results show a variability in the organic richness, thermal maturity and petroleum potential of the La Peña Formation, differentiating the values of the TOC content, petroleum potential and HI content for the samples from the Sabinas Basin and Piedras Negras Basin, respectively.

Reconstruction of fluvio‐lacustrine landscapes and settlement history in the Texcoco region, Mexico, using a modern geomorphic analog

AbstractLocated in the Basin of Mexico, the eastern shore of former Lake Texcoco sustained a variety of human occupations throughout the Holocene, including preceramic hunter‐gatherers, incipient agriculturalists, and a variety of settlements in the ceramic periods. Nonetheless, the environmental dynamics of occupations on the lakeshore have not been fully addressed. The Archaic preagricultural Texcoco Man site (>5000 B.C.E.) and the Late Formative TX‐LF‐14 site (c. 550‐200 B.C.E.), among others, occupy this fluvio‐lacustrine transitional environment. Few stratigraphic works in and around the sites have been performed. Consequently, it is difficult to understand the dynamics of the sedimentary system in space and time. This work highlights and describes the fluvio‐lacustrine sedimentary dynamics and the resulting landscape that past societies inhabited on the eastern shore of Texcoco Lake. Because the study area has been altered by historic and modern draining, our work employs Lake Santiaguillo and its main tributary, the Tejamen River in the Durango state, as a modern analog to study their sedimentary dynamics. The analyses of surface geomorphology in the Texcoco study area were employed to corroborate the modern analog interpretation. To achieve these goals, we conducted a GIS‐based morphometric analysis and LANDSAT‐8 imagery to study the variations in landforms through wet and dry events. The results indicate an increase in the lake volume, low bifurcation in the active fluvial channels, few inundated surfaces, and the presence of bird‐foot deltaic channels during high precipitation events. In contrast, low precipitation events are characterized by reduced lake volume, increased fluvial channel bifurcation, and expanded floodplains. This heterogeneous landscape thus provided a rich source of diverse natural resources of saline and freshwater aquatic habitats. Simultaneously, constant or recurring flooding events generated a challenging landscape for prehistoric settlers who implemented diverse technologies, such as the construction of tlateles, on the levees of deltaic channels to reduce the risk and impact of flooding events.

Assessment of Elongation of the Mesocotyl-Coleoptile and Biomass in Parents and Crosses of Corn Seedlings of the High Valleys of Mexico

The elongation of the mesocotyl and the coleoptile and other seedling traits were analyzed from 16 hybrids of two seed sizes, five varieties and a control. Sowing was conducted in sand beds during the S-F 2020 cycle, where nine genotypes were identified that differed in the elongation of the mesocotyl: long (H-48, HS-2 and Promesa); medium (H-44-H-52 and H-70); and short (H-49 AE, H-40 and H-32). A total of 36 possible crosses were obtained between these nine parents, which were established in the S-S 2021 cycle, and on sand beds. Results show that seed size affected (p< 0.05) the speed and percentage of emergence, the elongation of mesocotyl–coleoptile, the biomass and the heterosis in parents and their crosses. The H-48 hybrid presented greater speed and percentage of emergence and elongation of the mesocotyl and the coleoptile with both seed sizes. The highest dry weight of mesocotyl, coleoptile, roots, and leaves was found in the hybrids Promesa and H-48. The crosses between parents with contrasting mesocotyl presented superior elongation and dry weight (p ≤ 0.05) compared to their parents, with the long × long (1 × 2, 1 × 3 and 2 × 3) crosses standing out for all the traits measured. A strong positive association was obtained (p ≤ 0.01) between the elongation of the mesocotyl–coleoptile, the percentage of emergence, and the production of total dry matter in parents and their crosses.

First record of Melanaphis donacis (Passerini, 1861) (Hemiptera: Aphididae) in México

The aphid Melanaphis donacis (Passerini, 1861) (Hemiptera: Aphididae) is recorded in Mexico in seven locations in the Valley of Mexico Basin on the Poaceae Arundo donax, one of the most common host plants. Both the aphid and the host plant are species considered exotic to Mexico; especially A. donax is referred to as one of the hundred most important invasive alien species in the world and is also officially cited in Mexico. Observations and collections of both the aphid colonies and the host plant began in October 2022 to February 2023. The work includes the taxonomic determination of both the aphid and the host plant. Also reviewed of websites (www.naturalista.mx) where in two sites it was referred to in a preliminary way, without taxonomic certainty by a specialist. In addition to the worldwide distribution of the aphid species and its host plants. Parthenogenetic wingless and winged forms are presented and described in vivo, as well as in mounts of microscope slides. In all the cases observed in the field, a symbiotic association with ants of the species Linepithema humile Mayr, 1868 (Hymenoptera: Formicidae) is documented. Some natural enemies were obtained, such as Harmonia axididis (Palas, 1773) (Coleoptera: Coccinellidae); Scymninae, Chamaemyiidae and Syrphidae larvae, yet to be determined. It is suggested to increase the search both in other localities and in hosts potentially present in Mexico.

Predicting areal extent of groundwater contamination through geostatistical methods exploration in a data-limited rural basin

The areal extent of regulatory standard exceedance for groundwater arsenic, fluoride, and nitrate was estimated and compared for multiple methods to evaluate groundwater contamination in a rural basin of New Mexico, USA. First, three geostatistical kriging techniques – Ordinary Kriging (OK), Universal Kriging (UK), and Empirical Bayesian Kriging (EBK) – were explored. Next, the exploration was extended to multivariate analysis (Co-OK, Co-UK, and EBK-regression) using groundwater pH as the other variable, compared to interpolation only considering the contaminant as a primary variable. Finally, non-parametric Indicator Kriging (IK) was utilized for probability mapping and assessing the likelihood of surpassing critical thresholds for contaminant concentrations. The contamination area changes with different kriging methods deployed, and the performances of kriging variants vary for the three chemical components. The models that best fit the empirical data were determined. The study examined the influence of the explanatory variable on the multivariate kriging prediction accuracy. The multivariate kriging approaches enhanced surface prediction accuracy and tended to cover the data limitation of the primary variable interpolations. The multivariate kriging improved spatial prediction of arsenic and fluoride by increasing the Empirical Coverage Probability (ECP) up to 0.05–0.25 from case to case; however, no improvement was observed in ECP for nitrate contamination distribution, as the explanatory variable pH was only weakly correlated with nitrate, suggesting that a stronger correlation between the primary and secondary variables can increase the probability of obtaining prediction improvements through multivariate kriging. This study developed a methodology for characterizing and identifying locations where groundwater had elevated concentrations of contaminants, threatening human health through drinking water exposure. By improving the spatial characterization of groundwater contaminants within the data-limited rural basin, policymakers planning improvements will support mitigation strategies to manage contamination sources of groundwater resources.

Frictional and poromechanical properties of the Delaware Mountain Group: Insights into induced seismicity in the Delaware Basin

The Delaware Basin in West Texas and Southeast New Mexico has experienced a proliferation in seismic activity since 2016. The seismic activity is primarily due to subsurface injection of wastewater into shallow and deep reservoirs. However, the precise mechanisms connecting fluid injection to seismic activity are not well understood. To shed light on these processes, we measured rate-state friction and poromechanical properties of rocks sampled from the Delaware Mountain Group (DMG) at pressures and stresses representative of in-situ conditions. Experiments were conducted inside a pressure vessel and loaded at a true-triaxial stress state. The samples exhibit velocity-strengthening behavior and transition to velocity-neutral behavior with increasing slip. We also measure frictional healing and demonstrate that the healing rates are consistent with those measured from quartz-feldspathic-rich rocks. Experiments were conducted under a constant pore-pressure boundary condition where transient changes in pore-volume were compensated by modulating the fluid volume within the fault. Our data show that a step increase in sliding velocity leads to dilatancy and causes an influx of fluid into the fault. In contrast, a step decrease in sliding velocity causes the fault zone to compact and reduces fluid flow into the fault. Data show that changes in flow rate scale systematically with fault slip velocity. Broadly speaking, the frictional and poromechanical data indicate that shallow faults within the DMG should favor aseismic creep as opposed to unstable slip. Our data are consistent with elastic dislocation models of fault slip and InSAR data, indicating that faulting in the DMG is predominantly aseismic. The lack of velocity weakening behavior observed in our samples indicates that heterogenous frictional properties are needed to explain the co-existence of both aseismic and seismic slip in the DMG.

A methodology to prioritize ecosystem restoration of in-situ well pads in the Permian Basin of western Texas and southeastern New Mexico, USA

Since the mid-2000s, drilling and production of oil and gas activities have grown exponentially in the southwestern United States. The clearing of pre-existing vegetation and topsoil to build well pads is known to have a broad range of ecological, biological, hydrological, and health impacts, therefore ecosystem restoration of the well pads is generally required. This process, however, is often complicated by limited funding, various governing bodies and ownership, and frequent extreme weather events. To ensure that well pad construction does not result in damaging, irreversible environmental change in the region, a prioritization strategy is needed to maximize the effectiveness of restoration efforts. The objective of this study is to develop a methodology to prioritize well pads where ecosystem restoration is urgently needed. In this methodology, a set of locational soil (e.g., soil fragility, wind and water erodibility) and land cover (e.g., land cover, proximity to streams) attributes were derived from publicly available datasets and a restoration priority score system along with a weighting factor were assigned to individual attributes. Accordingly, a total restoration priority score (TRPS) was calculated for individual well pads. This methodology was applied to a dataset of >10,000 well pads located in the Permian Basin and the surrounding area. This method effectively filtered out a large number of sites with low TRPS, and identified a small portion of high-score, clustered well pads. The identification of such well pads makes the logistical challenge of targeted restoration much easier for stakeholders tasked with maximizing the effectiveness of restoration efforts with limited funding. Despite some known limitations and inaccuracies, this method is low-cost and can be easily adaptable to humid and sub-humid systems, and even to restoration relevant to non-oil and gas exploration activities, such as solar and wind development, in the southwestern United States and many other areas worldwide.

Highland islands: assessing gene flow among populations of an aquatic highland endemic

Abstract A variety of hierarchical gene flow models have been proposed to explain the distribution of genetic variation in aquatic environments. These models, including the Stream Hierarchy (SH), Death Valley (DV), Headwater (HW), and Widespread Gene flow (WG) models, provide testable hypotheses that focus on the degree of within-basin or within-stream network connectivity and an organism’s dispersal abilities. We tested these models using Tlaloc hildebrandi (Profundulidae, Cyprinodontiformes), a freshwater fish endemic to the highlands of the Grijalva and Usumacinta River basins in southern Mexico. Data from ultraconserved elements (UCEs) showed that although T. hildebrandi was recovered as monophyletic, the sub-basins were not. We generated single nucleotide polymorphisms from the UCEs to analyse the data in a population genetic framework. These results differed between analyses such that two (STRUCTURE analysis) or three (DAPC analysis) genetic groupings were recovered. Overall, the results of this study provide support for the SH model. Some individuals from the Jataté sub-basin, however, conformed to the HW model, due to historical connections among headwater streams and rivers of the Jataté and Amarillo–Chenalhó clades/clusters. The greatest degree of gene flow has occurred from the Grijlava to the Usumacinta basins, two geographically proximate basins that have been hypothesized to have had previous connections.

US climate policy yields water quality cobenefits in the Mississippi Basin and Gulf of Mexico

We utilize a coupled economy-agroecology-hydrology modeling framework to capture the cascading impacts of climate change mitigation policy on agriculture and the resulting water quality cobenefits. We analyze a policy that assigns a range of United States government's social cost of carbon estimates ($51, $76, and $152/ton of CO2-equivalents) to fossil fuel-based CO2 emissions. This policy raises energy costs and, importantly for agriculture, boosts the price of nitrogen fertilizer production. At the highest carbon price, US carbon emissions are reduced by about 50%, and nitrogen fertilizer prices rise by about 90%, leading to an approximate 15% reduction in fertilizer applications for corn production across the Mississippi River Basin. Corn and soybean production declines by about 7%, increasing crop prices by 6%, while nitrate leaching declines by about 10%. Simulated nitrate export to the Gulf of Mexico decreases by 8%, ultimately shrinking the average midsummer area of the Gulf of Mexico hypoxic area by 3% and hypoxic volume by 4%. We also consider the additional benefits of restored wetlands to mitigate nitrogen loading to reduce hypoxia in the Gulf of Mexico and find a targeted wetland restoration scenario approximately doubles the effect of a low to moderate social cost of carbon. Wetland restoration alone exhibited spillover effects that increased nitrate leaching in other parts of the basin which were mitigated with the inclusion of the carbon policy. We conclude that a national climate policy aimed at reducing greenhouse gas emissions in the United States would have important water quality cobenefits.