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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

At least 1,333 records · Page 74Linked to original sources

USGS2026

Evaluating the use of uncrewed surface vessels to enhance Lake Erie acoustic prey-fish surveys

Incorporation of autonomous uncrewed surface vessels (USVs) into large-scale acoustic surveys may enhance spatiotemporal extent and quality of fish density estimates. Lake Erie is currently surveyed by three motorized research vessels (RVs), which annually collect acoustic data and estimate prey-fish abundances. To evaluate the feasibility of incorporating a USV into the existing survey to increase spatial coverage, we compared paired acoustic measurements of target strength (TS), area backscattering coefficient (ABC), and areal fish density from four motorized RVs (three currently and one historically used) and one USV (Saildrone Explorer). Acoustic data were collected along 2-km transects during five sampling events distributed throughout Lake Erie. Despite observing event-specific differences that were likely impacted by sampling conditions, survey-level estimates of areal density between RVs and the USV were comparable (i.e., RV 6% lower than USV). RVs and the USV appear to react differently (speed and stability) to variable environmental conditions (wind and waves), which impacted data quality and must be mitigated in future applications. However, similar to previous comparisons in marine and freshwater environments, incorporating a USV into an acoustic survey could enhance annual fish density estimates by increasing effort, spatial coverage, logistical flexibility, and biological data collection opportunities from RVs.

Michigan, New York, Ohio, Pennsylvania↗

USGS2026

Quantifying post-fire live tree presence and spatial variation using Sentinel-2 time series

Accurate mapping of post-fire surviving trees is important for tracking forest recovery and prioritizing land management decisions. Satellite-based remote sensing is an effective method to assess post-fire forest conditions. Traditionally, differenced satellite-derived burn severity indices are computed by differencing one year pre- and post-fire spectral reflectance values. Differenced burn severity indices are useful for quantifying and mapping the magnitude of ecological change, but their application to detecting and mapping post-fire live trees may not be as appropriate, particularly for delayed tree mortality. Delayed tree mortality (“delayed mortality”) is a phenomenon where trees that initially survive fire then die over an extended period (between one and five years), and it can be challenging to measure and predict. In this study, we demonstrate the potential of mapping delayed mortality using readily available remotely sensed imagery alone. We used random forest models to detect post-fire live trees using 10-m resolution Sentinel-2 data at one-, three-, and five-years post-fire for four fires in the southern Sierra Nevada, California, USA. Using imagery from the National Agriculture Imagery Program (NAIP; 60-cm resolution), we manually classified live tree presence in 6000 Sentinel-2 pixels (500 pixels for each fire-year combination) to calibrate and validate models. Sentinel-2 based model accuracies ranged from 65 % to 86 % with F-scores ranging from 0.52 to 0.86, and their predictions of live pixel area were on average 44 % lower than inferred from more traditional indices such as relative differenced normalized burn ratio (RdNBR). This work represents a promising first step in using freely available post-fire spectral reflectance imagery to detect live trees over an extended period to support post-fire management.

California↗

USGS2026

Evaluating evidence of changing regional occupancy of four bat species in response to forest management practices

Coordinated, regional strategies to guide effective management and conservation of forests can be used to balance conservation with management for other objectives such as timber, scenic viewsheds, and fire. A key part of these regional strategies is incorporating knowledge of how management actions may affect certain species, especially those that are sensitive or are of concern. However, knowledge of how management actions may affect species is inferred from studies conducted across small areas where the species’ behavior and forest conditions are easily assessed. Here, we examine how occupancy of four bat species responds to forest management across the eastern United States at regional scales. We used range-wide capture and stationary acoustic surveys from the North American Bat Monitoring Program from 2010 to 2020 to estimate yearly summer occupancy for four bat species of conservation concern identified in the U.S. Department of Agriculture Forest Service (USFS) Southern and Eastern Regions Bat Conservation Strategy: little brown bat ( Myotis lucifugus ), northern long-eared bat ( Myotis septentrionalis ), Indiana bat ( Myotis sodalis ), and tricolored bat ( Perimyotis subflavus ), and assessed the degree to which occupancy of each species changed after different vegetation management actions were implemented on USFS lands. We identified 78 different management actions that were hypothesized to influence summer bat occupancy at two spatial scales (5-km and 10-km) across the eastern United States from the Forest Service Activity Tracking System and grouped these management actions into four vegetation management types: clear-cutting, fire, thinning, and ground vegetation management. To evaluate potential effects of these vegetation management types on bat occupancy, we created a yearly management metric representing the average number of years that had passed since any one of the included management actions in each management type had been implemented in each 5-km or 10-km grid cell, weighted by the proportion of the grid cell covered by the management treatment history. We chose these metrics to ask if more management or management done recently had a larger effect on bat occupancy than less management or management done long-ago. We then fit Bayesian hierarchical multi-scale occupancy models for each species to assess how occupancy changed in response to the amount and time since implementation of each vegetation management type. Using the estimated relationships between the yearly metrics of management and bat occupancy, we created predictions for how bat occupancy responded at 1- and 5- years after implementation. We found substantial differences in the response of the four species to the four vegetation management types. Ground vegetation management provided the greatest increase in expected occupancy at 1 year after implementation for little brown bat, long-eared bat, and tricolored bat, while fire provided the greatest increase in expected occupancy for Indiana bat. Thinning provided increases for all species at 1 year after implementation, but even greater increases at 5 years after implementation. Clear-cutting, on the other hand, tended to result in decreased occupancy at both 1- and 5-years after implementation for each species and had the greatest effect on tricolored bat at 1 year after implementation. Clear evidence for how management types like these may be affecting bat populations can be used at regional scales to help private and public forest managers achieve their strategic goals.

eastern United States↗

USGS2026

Fostering landscape resilience and species conservation in frequent fire landscapes

Restoration of dry forest landscapes of the Pacific Northwest often involves the removal of some closed-canopy forest that has expanded due to fire exclusion, but this can conflict with species conservation when species require closed-canopy forest as part of their habitat. Fire refugia—areas within fire perimeters that burn less severely or frequently—might provide a solution to this conflict. We used a species-specific approach to understanding fire refugia for northern spotted owls to model the post-fire persistence of nesting and roosting (NR) forest in the frequent fire landscapes of the eastern Washington Cascades and the Klamath province and parts of the southern Cascades. Persistent NR forest occurred in topographically sheltered locations and lower slope positions whereas less persistent NR forest occurred in topographically exposed locations. These patterns of persistence reflect historical vegetation patterns when complex interactions among topography, vegetation and weather maintained resilient landscapes. These vegetation patterns may also resemble higher quality heterogenous habitat for spotted owls. Our models can help managers achieve the dual objectives of maintaining viable populations of native species, including those that rely on closed-canopy forests, while also restoring resilient landscapes. In an era of rapid ecological change, we suggest that northern spotted owl conservation and fire-adapted landscape restoration are not opposing goals. By identifying the biophysical settings that promote persistent NR forest and acknowledging the role of heterogeneous landscapes for maintaining resilient ecosystems and high quality spotted owl habitat, the dual objectives of supporting long-term resilience for native species and ecosystems can be achieved.

California, Oregon, Washington↗

USGS2026

Root biomass and productivity in coastal swamp forests of Louisiana (USA)

Coastal swamp forests (CSF) occupy approximately 225,000 ha in Southeastern Louisiana (USA), and across a large percentage of this area, CSF are subjected to sediment starvation, salinity intrusion, and chronic submergence. We assessed root biomass and productivity in nine CSF in Louisiana, and found that root biomass ranged from 420.8 g m −2 to 1712.2 g m −2 to a soil depth of 30 cm. Root biomass generally increased with salinity up to a mean and maximum of 1.8 and 4.3 psu, respectively, deviating from how aboveground biomass typically patterns. Submergence is a likely explanation for this deviation given that fresher sites had long hydroperiods with deeper water than salinized sites. In contrast, root productivity over a single year ranged from 112.1 g m −2 y −1 to 844.1 g m −2 y −1 , but did not relate strongly to salinity. On average, 16–87% of live roots were replaced each year among sites, leading to root longevities of 1.5–6.3 years. Also, root turnover was generally lower at more saline sites and higher from freshwater sites under greater submergence. Periodic water drawdown as a result of management intervention to reduce long-hydroperiod, chronic flooding by re-connecting river or tide to degraded CSF might stimulate root productivity and biomass accrual. Sediment amendment, strategic breaching of levees and gapping, and river water re-introductions are possible management actions.

Louisiana↗

USGS2026

Valuing socio-economic and ecological attributes of forested watershed restoration to reduce wildfire risk in the southwestern U.S.

Forest restoration in a watershed can provide numerous ecological improvements and social benefits, including reducing the risk of extreme wildfire. Understanding the values of the accrued benefits can be used to evaluate the use of funds to support restoration. The Rio Grande watershed is a vast watershed covering approximately 335,000 mile 2 (867,646 km 2 ). The Rio Grande watershed provides a host of ecosystem services and recreation opportunities and supports municipal water supplies. We estimate the non-market values of forest restoration in the Rio Grande watershed using a choice experiment (CE) approach. While the ecological benefits are established in literature, we focus on the social characteristics, capturing the human-forest system in a comprehensive manner. Our results indicate a significant willingness to pay (WTP) for improving air quality, reducing private property damage, and creating local jobs, with the highest WTP for job creation. Split-sample analysis indicates respondents residing within the watershed highly value the socio-economic attributes of the restoration, while ecological attributes are preferred more outside of the watershed. Our results provide insights into the benefits of multi-dimensional services from forest restoration activities in a watershed.

New Mexico↗

USGS2026

Organic and isotopic indicators for sorting of sedimentary organic matter along a marginal submarine canyon

Submarine canyons are incised features of many continental margins that can have significant influence on the hydrodynamic distribution of sediments and organic matter eroded and deposited from the continents. Baltimore Canyon, on the mid-Atlantic margin of the United States, contains a complex set of sedimentary processes that simultaneously create unique benthic habitats and control the deposition of organic matter. Along the canyon axis, loci of net erosion, net deposition, and intense winnowing each host diverse faunal assemblages and varying mixtures of sedimentary organic matter derived both from production in the overlying water column and from mobilized sediments. Bioavailable components of this deposited organic matter sustain benthic communities, while recalcitrant components can contribute to long-term carbon burial in the deep sea. However, commonly employed bulk geochemical analyses provide little information about the relative bioavailability or depositional history of sedimentary organic matter. Here we employ a range of organic and isotopic analyses to explore in more detail how canyon-specific sediment dynamics determine the sorting of organic matter from shelf to open ocean. In combination with bulk geochemical characteristics, we subjected surface sediments from water depths of ∼200–1200 m in Baltimore Canyon to a sequential extraction procedure, isolating nonpolar and polar lipid classes, an acid-soluble fraction, and an acid-insoluble fraction. Each class was analyzed for carbon and nitrogen quantities and stable isotope ratios, and radiocarbon content where possible, along with compound-specific carbon and nitrogen isotope analysis of individual amino acids in the acid-hydrolysed fraction. We find different organic matter sources and depositional history recorded in the properties of younger, bioavailable organic matter components (polar lipids, amino acids) in comparison to the older, more recalcitrant components (nonpolar lipids, acid-insoluble fraction). These differences in source and bioavailability of organic matter vary along the canyon, correlating with grain size and erosion/deposition dynamics, and may help shape the benthic faunal assemblages. Additionally, our results suggest that determining the relative concentrations of acid-soluble and acid-insoluble organic matter may provide an easily accessible method to improve our understanding of the nutritional quality of sediments for benthic fauna than more commonly used bulk carbon or nitrogen concentrations.

Delaware, New Jersey↗

USGS2026

Status assessment of peregrine falcons in North America using integrated population models

Species status assessments require an understanding of underlying population dynamics and important drivers of species demography. Large-scale assessments can be difficult due to challenges collating data obtained through different methods and different sources at multiple scales. Integrated population models (IPMs) provide a unified framework to combine multiple data sources and jointly estimate population parameters over a large spatiotemporal scale. We developed separate IPMs to estimate abundance and demographic rates for a northern (NMP) and southern (SMP) management population of peregrine falcons ( Falco peregrinus ) in North America from 2008 through 2019 (SMP) and 2020 (NMP). An outbreak of highly pathogenic avian influenza (HPAI) starting in 2021 led us to extend our modeling effort to assess its impact on these management populations by updating both IPMs using index data of population size through 2024 in a predictive framework. Survival probabilities differed drastically between first-year and after-first-year individuals in both management populations. After-first-year survival was nearly identical between the NMP and SMP, but first-year survival was lower in the SMP. Mean productivity was significantly lower in the NMP compared to the SMP, whereas the probability of breeding was similar in both management populations. Estimated total abundance for the NMP was substantially larger than the SMP, representing most of the North American peregrine population. Population growth was positive for both management populations, albeit at a slower rate for the NMP. The NMP declined from 2017 to 2018 coinciding with a drop in 2018 estimated productivity. When we extended the IPMs with updated count data through 2024, the NMP slightly declined but estimated abundance remained above levels at the start of the time series analyzed. The SMP grew at a similar rate to that predicted during the period informed by demographic data. We did not detect a continental-scale change in population size or trajectory in either management population associated with the arrival of HPAI in 2021. Further monitoring can support determination of whether the declines in the NMP were temporary, can enhance understanding of the underlying mechanisms, and can be used to guide the conservation and management of the peregrine falcon population in North America.

North America↗

USGS2026

Carcass size and ground substrate drive detection rates of avian carcasses by human surveyors and a dog team

Accurate avian mortality estimates are essential for understanding anthropogenic impacts to bird populations and informing conservation strategies. Carcass surveys are commonly conducted by human surveyors or by detection dogs, but the factors influencing surveyor detection abilities have not been fully explored. In this study, we conducted two years of detection trials in the semi-arid high desert of southern New Mexico, USA, testing 27 human surveyors and one conservation detection dog across 1096 trials with 238 carcasses representing 50 avian species. We directly compared detection abilities between surveyor types (human and dog) and identified key factors influencing detection probabilities. The conservation detection dog exhibited a significantly higher detection probability (mean = 0.87) than human surveyors (mean = 0.49, individuals ranged 0.25–0.71), consistent with previous studies. Detection probabilities for both surveyor types were influenced by carcass size and ground substrate; detection probability was higher for larger carcasses and areas with lower vegetative complexity. We discuss our results in the context of common tradeoffs faced by managers in designing carcass surveys and how guidance may vary under different scenarios. Broadly, our study provides valuable insight that can enhance wildlife mortality monitoring, ensuring more accurate mortality estimates to inform management and conservation efforts.

New Mexico↗

USGS2026

Leopard occupancy and habitat use in the multi-use Chitwan-Annapurna Landscape, Nepal

We estimated leopard ( Panthera pardus fusca ) occupancy in a multi-use region within Nepal’s Chitwan-Annapurna Landscape to evaluate leopard habitat use and inform conservation planning in areas where most of the species’ habitat occurs outside protected areas. In 2021, sign surveys were conducted along 1277 km of transects distributed among 145 grid cells of 7×7 km within a 7105 km² study area, where 226 leopard signs (pugmarks and scats) were documented. We used an occupancy modeling framework to evaluate the influence of environmental and anthropogenic factors on leopard habitat use. We found that leopard occupancy (ψ = 0.73 ± 0.17 CI) was strongly and positively associated with areas used by wild prey such as red muntjac ( Muntiacus muntjak ), rhesus macaques ( Macaca mulatta ), chital ( Axis axis ), and wild boars ( Sus scrofa ). Our results provide evidence that large carnivores like leopards can persist in human-dominated landscapes when native prey remains abundant, underscoring the need for community-based conservation that sustains both prey and predator populations beyond protected areas. By estimating leopard occupancy outside of protected areas, the research establishes a baseline for developing management strategies to ensure the continued existence of leopards in Nepal's multi-use landscapes.

Chitwan-Annapurna Landscape↗

USGS2026

Revisiting the geochronology of late Quaternary marine terraces and uplift rates in coastal Santa Barbara County, California, USA

In several early studies, central California marine terraces between Santa Barbara and Point Conception were interpreted to record sea-level high stands of the last interglacial complex, ∼80 ka to ∼120 ka (marine isotope stage [MIS] 5). These ages and their elevations (∼20 m to ∼45 m) indicate modest rates of tectonic uplift, similar to those from other localities in southern and central California. A recent study, using a combination of luminescence and radiocarbon dating, has challenged the older age interpretations, implying much younger terrace ages, between ∼40 ka and ∼55 ka (MIS 3). From these new ages and a considerably lower sea level during MIS 3, much higher rates of tectonic uplift are inferred. In the present study, new uranium-series ages of terrace corals and amino acid age estimates of terrace mollusks were determined to test these competing interpretations. With the exception of a low-elevation terrace in Isla Vista (near Santa Barbara) that dates to MIS 3, terraces farther west are interpreted to date to MIS 5 and imply tectonic uplift rates of 0.20–0.34 m/kyr. A compilation of data for the region yields a decreasing rate of late Quaternary uplift from east, near Ventura, to west, near Point Conception. This trend is interpreted to reflect a decreasing influence of the processes of compression and crustal shortening south of the Big Bend in the San Andreas fault.

California↗

USGS2026

Sustainability trade-offs at the nexus of solar energy, agriculture, and biodiversity

A rapid transition to renewable energy is necessary for achieving global decarbonization targets, but siting conflicts, particularly beyond the built environment, remain a key barrier to sustainable development. At the same time, climate-induced pressures on biodiversity intensify the socio-ecological trade-offs within the energy-agriculture-biodiversity nexus. Using New York State as a case study, we assess the geographic implications of utility-scale solar energy development under competing land-use priorities. We apply a mixed-integer linear programming (MILP) optimization model to evaluate solar buildout across three distinct scenarios: minimizing cost, prioritizing agricultural preservation, and conserving biodiversity, employing a lexicographic hierarchy to enforce a strict ordering of stakeholder priorities. Results indicate that New York can meet its mid-century decarbonization goals by deploying 46,216 MW dc of solar energy, however, achieving this goal involves considerable land-use trade-offs. A cost-minimizing scenario disproportionately targets pasture and hay lands (>40,000 ha), nearly half of which overlap with grassland bird habitat and broader biodiversity areas. Prioritizing agriculture spares ∼80 % of farmland but creates potential for deforestation of over 41,000 ha. Biodiversity-conscious siting avoids ecologically sensitive areas and increases the annualized total costs by 0.17 %, indicating economic feasibility. Our findings highlight the need for spatially informed, integrative land-use strategies that reconcile climate goals with ecological and agricultural values. By linking geospatial optimization with socio-ecological criteria, this work contributes a transferable framework to inform just and ecologically responsible energy transitions in multifunctional landscapes, offering new insights into how geography can advance sustainable development.

New York↗

USGS2026

Top-down targeted network analysis of critical mineral commodities applied to international geochemistry database

The global demand for critical mineral commodities is rapidly increasing, making domestic production an important factor in supporting the economy and national security. Large scale, publicly available geochemical databases allow for the application of data informatics methods to interrogate critical mineral commodities data for correlations in deposit formation and distribution, particularly for identifying enrichment of multiple critical mineral commodities at the same deposit. In this study, we applied network analysis to the Critical Minerals Mapping Initiative (CMMI) ore geochemistry (Critical Minerals in Ores, CMiO) database to identify the high concentration (defined as 10× bulk crustal abundance) co-occurrence of different critical mineral commodities across a mineral system hierarchy from deposit environments to individual deposits. Identifying patterns or unique outliers in enrichment in network communities will allow for the location of secondary critical mineral commodity resources from under-utilized deposits. We find trends in the enrichment of critical mineral commodities in network-communities between the elements praseodymium (Pr), neodymium (Nd), terbium (Tb), and dysprosium (Dy) across multiple CMiO database deposit environments and groups down to specific deposit types and sites. A separate trend in network community deposition is observed as well between iridium (Ir) and platinum (Pt) in deposit environments, groups, types, and sites. Network analysis focused on critical minerals in magmatic-hydrothermal deposits identified multiple deposit sites from different deposit types within the CMiO database with concentrations of Dy, Nd, Tb, Pr, Ir, and Pt that are at least ten times greater than the crustal average. This approach can be applied to any target element(s) or deposit(s) of interest, allowing broad investigation of co-enriched critical mineral commodities.

Journal of Geochemical Exploration↗

USGS2026

Early Pliocene (Zanclean) sea surface temperature for PlioMIP3

Paleoclimate researchers have been comparing Pliocene environmental data to paleoclimate model results since the 1980s. The Pliocene Model Intercomparison Project (PlioMIP) began in 2008 with a focus on the Late Pliocene. Here we assess the availability and utility of sea surface temperature (SST) data for verification of Pliocene Model Intercomparison Project (PlioMIP3) Early Pliocene (Zanclean) experiments. We analyze published data in terms of quantity and spatial distribution. Only SST estimates derived using alkenone paleo thermometry are reported, and all estimates are based upon the same temperature calibration. Sea surface temperature data are selected from within three distinct time intervals: The early Zanclean 5.3 Ma – 4.2 Ma time slab, and two time slices within the early Zanclean, chosen by PlioMIP3 at 4.870 Ma and 4.474 Ma. Results show the early Zanclean time slab contains 2055 individual estimates. Approximately ∼ 80% of these estimates come from Sites 609, 642, 846, 847, 882, 907, and 1146. There are 17 sites with a total of 42 estimates within the 4.474 Ma ±10 kyr time slice, and 15 sites with a total of 47 data points within the 4.870 Ma ±10 kyr interval. The sparse spatial and temporal distribution of Zanclean data, relative to the data available for the mid Piacenzian, makes point-by-point data model comparison suspect. We suggest interpreting model output against lower resolution long term trends in proxy data, and comparison of models through temperature gradients, may be the most useful application of currently available data. Integrating Zanclean age coastal plain sequences within data model comparison schemes, for increased understanding of regional climate impacts, also holds great potential.

Global and Planetary Change↗

USGS2026

Revisiting chlorophyll a thresholds for San Francisco Bay: Insights from observations of phytoplankton molecular abundance

Harmful Algal Blooms (HABs) are a hazard for coastal environments worldwide; identifying screening thresholds of chlorophyll- a (chl- a) associated with increased risk of HABs is a management priority. Molecular surveillance of coastal phytoplankton and bivalve biotoxins could be used to link chl- a with HAB risk, but requires an understanding of whether the HAB risks increase uniformly as chl-a rises, or whether some taxa are disproportionately favored, and if these relationships vary by season. In this study, we present a novel use of molecular abundance data to investigate the scientific bases for estuarine chl- a thresholds protective against HABs. In San Francisco Bay (SFB), California, the relationship between molecular relative abundance (as measured by 18S metabarcoding) of nine different HAB taxa, absolute quantitative polymerase chain reaction (qPCR) abundance, and mussel toxin concentrations of a subset of the taxa were investigated for thresholds as a function of increasing chl- a . Our results show most HAB taxa did not increase in absolute or relative abundance during SFB’s spring bloom interval, when chl- a levels were highest (>10 µg/L) but the assemblage was dominated by non-harmful diatoms. However, several flagellated, mixotrophic taxa did increase above their molecular baseline in fall, and the combined probability of any HAB occurring above baseline was elevated when chl- a reached ∼4.6 µg/L in the fall. This work demonstrates the promise of molecular approaches in disentangling the seasonally complex interplay between stressors and phytoplankton/HAB community responses and has the potential to provide clearer, more cost-effective monitoring and mitigation strategies for managers.

California↗

USGS2026

Downstream persistence of cyanobacteria in New Jersey's Raritan River basin

Few studies have examined cyanobacteria persistence starting from lacustrine cyanobacteria harmful algal blooms (HABs) downstream. Multiple lakes and reservoirs within New Jersey's Raritan Basin Water Supply Complex (RBWSC) feature recurrent HABs and discharge water into the Raritan River. As the RBWSC provides drinking water to 1.5 million people, these HABs create drinking water treatment and human health concerns. This study quantitatively reviews the persistence of cyanobacteria communities across the RBWSC from cyanobacteria-dominated lacustrine sources to downstream drinking water and qualitatively assess what, if any, water chemistry parameters influenced the persistence, growth, or decline of cyanobacteria during downstream transport. Statistical tests showed there was a lack of continuity between cyanobacteria communities along the Raritan River, except for periods of higher streamflow and higher releases from the Spruce Run Reservoir. Results along the Millstone River suggested the potential for in-river cyanobacteria growth, which overlapped with periods of low streamflow and high nutrient concentrations in the summer and fall. A permutational analysis of variance (PERMANVOA) test found significantly dissimilar ( p < 0.01) cyanobacteria communities between lake and reservoir outlet sites and downstream sites in the Raritan, but not the Millstone River ( p = 0.928). A similarity percentage (SIMPER) analysis found cyanobacteria communities changed from high densities of bloom forming cyanobacteria ( Aphanocapsa, Aphanizomenon, Microcystis) at the lake outlet sites to low densities of non-bloom forming cyanobacteria ( Synechcoccus, Chroococcus) along the Raritan mainstem, with Aphanocapsa the most notable bloom forming genera overlapping between sites. Investigating cyanobacteria on a watershed-specific basis could enhance understanding of the site-specific transport mechanisms and water chemistry parameters that facilitate community persistence.

New Jersey↗

USGS2026

Mars as one system: Insights from the 8th international conference on Mars polar science and exploration

The 8th International Conference on Mars Polar Science and Exploration (ICMPSE) provided new insights into the complex interplay between Martian ice, climate, and atmospheric dynamics. The conference emphasized a holistic view of Mars as a system, where surface processes, subsurface ice, atmospheric dynamics, and historical climate shifts are interconnected. Research updates spanned cutting-edge remote sensing techniques and observations, terrestrial analog studies, and theoretical modeling, providing a multidimensional view of Mars' dynamic history and present-day activity. Numerous presentations highlighted the importance of understanding Mars as an integrated and dynamic system where surface and atmospheric processes interact over various timescales. This paper synthesizes unresolved questions and the major themes discussed, including mid-latitude glaciation, the evolution of the polar layered deposits (PLDs), terrestrial analog studies, climate modeling, and future mission planning. The findings contributed to refining models of Martian climate history, assessing the potential for extant life, and planning future human exploration. We also discuss the historical perspective of Mars Polar Science and new findings since the 7th conference in this series and anticipate the next four to 20 years of science on Mars related to ice, climate, and the atmosphere.

Icarus↗

USGS2026

Lunar analog study using portable gamma-ray neutron detector: Radiochemical mapping of silicic-to-basaltic volcanic terrains in the San Francisco Volcanic Field, Arizona

Studying lunar silicic volcanism provides key insights into the Moon’s crustal evolution, magmatic processes, and volcanic history. The Lunar-VISE (Lunar Vulkan Imaging and Spectroscopy Explorer) mission will investigate the Gruithuisen domes, a unique lunar region hypothesized to have formed through silicic volcanism. Using instruments on a Firefly Aerospace lander and a Honeybee Robotics rover, Lunar-VISE will analyze mineralogy, geochemistry, and surface properties to determine the origin and evolution of the domes, with a gamma-ray and neutron spectrometer (LV-GRNS) among its payload instruments. In preparation for this mission, we conducted preliminary fieldwork using a handheld gamma-ray neutron detector with NaI(Tl) and Cs LiYCl :Ce (CLYC) scintillators. This study focuses on various rhyolitic and basaltic volcanic centers in the San Francisco Volcanic Field (SFVF) near Flagstaff, Arizona—specifically Sugarloaf Peak, Bonito Lava Flow, and Robinson Mountain, a region containing several well-characterized lunar analog sites. The SFVF was selected for this study due to its broad compositional diversity spanning basaltic to rhyolitic compositions, its well-preserved volcanic morphologies, and its extensive use in previous NASA field campaigns and astronaut training exercises, making it an ideal terrestrial laboratory for testing planetary exploration techniques. We measured natural radioactivity, specifically from potassium (K), thorium (Th), and uranium (U) and other elements in their decay chains, which serve as diagnostic tracers of magmatic differentiation and crustal evolution processes, to assess geochemical variability across compositionally diverse terrains. The detector’s sensitivity was assessed across varying concentration levels. Regionally averaged concentrations of radioisotopes were determined by gamma-ray spectroscopy at selected sites. Our measurements reveal significant compositional variations between sites, with Sugarloaf Peak (rhyolitic, silicic dome) exhibiting the highest average radioisotope concentrations (K: 3.29 ± 0.24 wt%, U: 14.35 ± 1.81 ppm, Th: 27.14 ± 2.43 ppm), while Bonito Lava Flow (K: 1.13 ± 0.08 wt%, U: 3.86 ± 0.52 ppm, Th: 7.52 ± 1.02 ppm), and Robinson Mountain (K: 1.46 ± 0.16 wt%, U: 5.59 ± 1.06 ppm, Th: 11.75 ± 1.98 ppm) show lower concentrations aligned with basaltic compositions. Gamma-ray fluxes were elevated by a factor of approximately three to four at Sugarloaf Peak relative to nearby basaltic terrains, consistent with expected geochemical differentiation patterns. Furthermore, at meter scales, proximity to geological features significantly affects measurements. Th concentrations adjacent to a cliff face at Sugarloaf’s base were 28% higher than values measured 3-5 meters away from the same feature, demonstrating localized compositional heterogeneity. Analysis of station-by-station measurements reveals that K, U, and Th concentrations show an elevation trend at Robinson Mountain and generally higher concentrations near Sugarloaf Peak’s summit, suggesting progressive magmatic differentiation and/or the presence of more evolved lithologies at higher elevations. By mapping these elements on Earth using GRNS, we aim to optimize measurement techniques for Lunar-VISE and similar rover-borne missions by demonstrating the applicability of portable GRNS instruments for planetary surface exploration in an analog environment.

Arizona↗