9 Apr 2026

Identifying Overwintering Habitat of Silver and Bighead Carp in the Lower Mississippi River: Implications for Harvesting and Population Reduction

Purpose: A total of 41 sites along a 58 mi reach of the Lower Mississippi River (LMR) were surveyed during winter 2022 for invasive carp aggregation. Sites consisting of scallops closest to the dike-vegetated bank interface with deeper, slow-moving water and consistent access back to the main channel were preferred. Carp avoided strong currents, and there was no trend in depth selection other than avoiding shallow (less than 20 ft) water. In January 2023, recreation-grade sonar (e.g., side-scan and down-imaging) surveys were conducted in the same reach of the LMR to demonstrate the technology and evaluate carp population size at sites with high abundances based on previous surveys. Fish density was estimated to be 32 fish/10,000 yd3 (95% confidence interval [CI; 31–34]) using down-imaging software, which is the first estimate of assumed bigheaded carp density in the LMR. Additional fish collections are needed to confirm species composition and size abundance provided by sonar technology. Resurveying sites with high carp abundance over a range of river stages would be necessary to fully characterize habitat conditions, evaluate influence of river stage on occupancy duration, and continue to evaluate species composition and mass removal techniques as a management option in the Lower Mississippi River.

9 Apr 2026

Photocatalytic Degradation of Microcystins from a Field-Collected Cyanobacterial Assemblage by 3D Printed TiO2 Structures Using Artificial Versus Solar Irradiation

Abstract: Microcystins from freshwater cyanobacteria cause adverse effects to humans and ecological receptors through multiple exposure routes requiring adaptable and diverse treatment technologies. Photocatalysis of MCs using TiO2 is a promising technology; however, TiO2 photocatalysts as unbound nanoparticles in suspension are impractical to deploy. 3D Printing provides a means to immobilize TiO2, producing deployable photo-catalyst structures with extensive geometric freedom. The objective of this proof-of-concept experiment was to incrementally increase the environmental complexity while comparing photocatalysis rates of MCs by 3DP TiO2 structures using polylactic acid as the binder. Degradation half-lives of MCs were shorter in TiO2 embedded in 3DP PLA relative to PLA-only controls with differences in half-lives ranging from 3.6 to 10h. The one exception was the outdoor solar and an algal assemblage, where significant differences could not be discerned due to the already rapid photolysis rates. Ultimately, photocatalysis rates were comparable to those previously published for TiO2 3DP structures in a laboratory environment and TiO2 fixed- films demonstrating feasibility of 3DP to immobilize TiO2 photocatalysts under a range of conditions. This is the first time that MC concentrations from a field-collected HAB were photocatalytically degraded in both solar simulated light and sunlight using a custom-made advanced photocatalytic nano- composite with enhanced performance through high surface area design enabled by 3D printing. These data inform future development of scalable, retrievable, and operationally flexible structures with immobilized TiO2.

9 Apr 2026

Round Robin Experiment to Detect, Size, and Characterize Flaws in the Welds of Existing Hydraulic Steel Structures Using Phased Array Ultrasonic Testing

Abstract: Limited information exists on the ability of nondestructive testing techniques to detect, size, and characterize flaws in existing hydraulic steel structures (HSS). Round robin experiments were conducted using phased array ultrasonics to inspect welded steel specimens representing joints in existing HSS. Technicians detected 83% of the flaws scanned, but detection rates varied widely by flaw and technician. Uncertainty in flaw size estimates, represented by 90% confidence bounds on the ratio of estimated to actual length or height, ranged from 0.52 to 2.10 for length and 0.32 to 3.59 for height. Planar, volumetric and laminar flaws were accurately characterized 80% of the time.

9 Apr 2026

Effects of Exopolysaccharides from Rhizobium tropici on Transformation and Aggregate Sizes of Iron Oxides

Abstract: Iron oxide transformations in soil significantly impact nutrient availability and plant health. This study investigated the interaction between exopolysaccharides (EPS), produced by Rhizobium tropici, and iron oxide (Fe3O4), focusing on their impact on the transformation, particle size, and zeta potential of iron oxides. The characterization of the EPS-iron oxide composites was carried out using X-ray Powder Diffraction (XRD), Fourier Trans-form Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Analysis (EDX). The EPS adsorption kinetics revealed chemisorption and diffusion as controlling processes for EPS adsorption on Fe3O4, while isotherm data with releasing proton indicated possible ion exchange and heterogeneous layered adsorption. Desorption studies suggested the high stability of EPS-iron complexes. Notably, EPS significantly increased the aggregate size of EPS-iron complexes at low EPS/iron oxide molar ratios but shrank the aggregate size at higher ratios. Additionally, EPS complexation resulted in a shift in the zeta potential towards more negative surface functionality. Functional groups within EPS, specifically –COOH, –OH and –NH played a crucial role in the interaction of EPS with iron oxides. The study concluded that EPS coating prevented the transformation of Fe3O4 into other iron oxide forms like β-FeOOH, α-Fe2O3, and γ-Fe2O3, elucidating the significant role of EPS in soil mineral processes.

9 Apr 2026

Vertebrates in Trade that Pose High Invasion Risk to the United States

Abstract: The United States imports thousands of live vertebrate species annually as part of legal trade. Escapes and releases from captivity are major pathways of invasion, however, the risk posed by the thousands of imported vertebrate species has not been systematically assessed. We conducted a horizon scan that used a data-driven climate match to filter a list of nearly 15,000 taxa drawn from across the globe of imported fish, amphibians, reptiles, birds, and mammals for rapid assessment by taxonomic experts. Experts evaluated 840 species and identified 32 as having the highest risk for establishment, spread, and negative impacts. Of those high-risk species, the majority have the capacity to disrupt ecosystem processes via their role as top predators or the unique ecological niches that they occupy, while several of the snake species pose a threat to human health. High-risk species were often scored with high confidence while in contrast, low scores were attributed to a combination of ecological redundancy, low propagule pressure, or low climate match while low confidence arose from a lack of information in the literature. Our study therefore highlights legally imported species likely to cause the greatest harm with the recognition that many other species could also become invasive in the United States. The ranked list of vertebrate threats can be used to prioritize watchlists and inform the development of targeted regulations for importation can be applied to regions to provide a rapid, preliminary screening for large pools of potential invaders.

8 Apr 2026

Phase-pure Formamidinium Lead Iodide Perovskite Films Deposited via Flow-Limited Field-Injection Electrostatic Spraying

Abstract: Phase-pure perovskite formamidinium lead iodide (FPI) films were deposited using flow-limited field-injection electrostatic spraying at a deposition temperature of 120 ○C without employing stabilizing additives while retaining large-area scalability. The structures of the films were analyzed using the Rietveld refinement of x-ray diffraction measurements, enabling achievement of phase purity under optimized charging voltage and deposition temperature. The effect of precursor molar ratio on the phase of FPI was investigated by Fourier transform infrared spectroscopy, revealing the crucial role of the FAPbI3 ⋅ DMSO adduct formed in solution for achieving phase purity. Optical properties and photoactivity were assessed by absorption spectroscopy and time-resolved photoluminescence, demonstrating viability for application to solar cells.

8 Apr 2026

Powering the Monitorization of Uninterruptible Power Supplies

Purpose: The danger of invasive species and the ecological impact on natural environments can be seen throughout the world. In the United States, the invasive species problem is being addressed in the Mississippi River and the tributaries that feed it where invasive carp were introduced and invaded, threatening native species and ecosystems. To battle invasive species’ movement into naïve watersheds, the underwater Acoustic Deterrent System (uADS) was developed by the US Army Corps of Engineers (USACE) to stem the migration of the invasive carp through navigation locks. This project serves as a vital effort to preserve the natural balance of aquatic life in the Mississippi River and those waterways that are connected to it. The project highlights the crucial need for systems that monitor the health of the hardware that keeps the project alive in the event of power failure or other disasters. The ability for researchers to quickly check the health of various systems, receive notification of failure, and see visualizations of hardware data is indispensable when a failure with a poor response time could allow these species to move through points where the system is in place. This paper will discuss the process of using containerization to address the monitorization needs of such systems and how containerization may allow for systems to be created quickly while still allowing for easy access to the needed data.

8 Apr 2026

Incubation Temperature and Urea Addition Impact Bacterial Composition and Voltage Output by Electroactive Bacteria

Abstract: Soil based terrestrial microbial fuel cells, traditionally used as batteries, could also serve as biosensors whereby the addition of an anthropogenic compound changes their voltage output. The ability and rate of electron transmission at the anode surface shifts based on external stimuli. This study investigates microbial response to diurnal temperature cycles and whether the shifts obscure voltage changes induced by the addition of urea. Replicate tMFCs were constructed with either 70 mg/ml urea or water and incubated at either a 25 ◦C static or 10 ◦C to 25 ◦C cycling temperature regime. Voltage was measured for 30 days and the tMFC electrodes were destructively sampled to determine bacterial taxonomy. Though voltage of all tMFCs increased throughout the incubation period, those exposed to urea had an output of 692 mV compared to 1011 mV observed in the controls. In both control and urea tMFCs, maximum voltage output during peak performance was significantly greater in the static temperature incubation than in cyclic. Bacterial diversity was significantly higher in the control tMFCs and was significantly higher at the cathode surface under cyclic temperature conditions. A previously trained machine learning model was able to accurately discern control vs. urea tMFCs despite the diurnal temperature conditions with 99% accuracy. These data show that diurnal temperature fluctuations had minimal impact on the bacterial community, and the presence of a contaminant was a strong predictor of tMFC community composition.

7 Apr 2026

Vehicle and Unpiloted Aerial System Interferometric Synthetic Aperture Radar Data Collection and Processing

Abstract: Interferometric synthetic aperture radar (InSAR) systems have a wide breadth of cold regions science and engineering applications such as determining snow water storage, permafrost thaw induced subsidence and frost heave of the active layer, and ground slope and infrastructure stability in permafrost dominated regions. Here, we present project planning, data collection, and processing workflows from two L-band InSAR systems, L-band SAR (GS-L) and UAS-mounted (GLSAR). The GS-L platform is integrated on a mobile, ground-based platform while the GLSAR is integrated on an uncrewed aerial system (UAS). We describe the postprocessing steps to produce radar back-scattered power and interferograms for the analysis of subsurface and near-surface phenomena. These steps are common to all the sensors discussed in this report and include kinematic postprocessing of the sensor positions, focusing on the raw radar returns in range and azimuth to form the radar image, and calculating the interferometric phase between acquisitions. With examples from each platform, we demonstrate the utility of these InSAR sensors and discuss acquisition scenarios in which either ground-based or UAS-borne systems may deliver higher-quality information from one another.

2 Apr 2026

Analyzing Historical Snow Trends in Interior Alaska

Abstract: This study examines 40 years (water years 1982–2021) of snowpack characteristics to consider its hydrological implications in the 5350 km² Chena River basin. Using observations and a fine-scale physics model, we analyzed trends of snow water equivalent (SWE), snow onset and disappearance, and snow cover duration (SCD). New hydrological insights for the region: Results indicate a decline in SWE across the modeled domain, averaging a decrease of 3 mm per decade, with larger decreases (up to 10 mm per decade) at lower elevations. While domain-averaged SWE trends were not statistically significant, observed SCD showed statistically significant decreases: - 5.2, - 5.0, and - 4.4 days per decade at Teuchet Creek, Fairbanks F.O., and Little Chena Ridge, respectively. Notably, observations at SNOTEL stations and modeling revealed no statistically significant change in domain-averaged Rain-on-Snow (ROS) events over the 40-year period, contrasting some regional future estimates of increased ROS frequency. Peak streamflow did not consistently correlate with peak SWE levels, suggesting that other environmental factors such as ROS events and rapid temperature increases (e.g., a 10◦C spike observed in 1992) are key drivers of hydrological outcomes. These findings improve understanding of complex subarctic hydrological processes impacting permafrost and highlight the need for adaptive water resource management to mitigate multi-factor risks like flooding and wildfire, requiring proactive planning.