23 Apr 2026

Development of an Agnostic Reservoir Model to Explore Wildfire Impact on Water Quality

Abstract: Despite the growing global concern surrounding the havoc caused by wildfires, there are still prominent gaps in knowledge regarding fire effects on nearby waterways. An agnostic CE-QUAL-W2 model was developed to look at the impact of wildfires on reservoir water quality, with a focus on harmful algal blooms. The model was informed using ten years of meteorological data from sites in the Pacific Northwest, United States. Wildfire scenarios were generated (one each for May, June, July, August, and September) using changes in temperature, total suspended solids, nutrients, dissolved oxygen, organic matter, and solar radiation typical of wildfires, informed via literature review. Harmful algal blooms showed the most sensitivity to fires that occurred prior to the growing season, likely due to the influx of phosphate accumulating in the system prior to growth. However, accumulation of nutrients for fires after the growing season showed impacts on blooms the following year. Increases in total dissolved solids during the fire could potentially lead to delays in initial bloom timing due to temporary light limitation. Results from the model runs indicate that wildfires can impact reservoir water quality and bloom dynamics not only immediately, but for months to years following a wildfire.

22 Apr 2026

An Interdisciplinary Overview of Levee Setback Benefits: Supporting Spatial Planning and Implementation of Riverine Nature-Based Solutions

Abstract: Nature-based solutions are increasingly recognized as multi-benefit strategies for addressing the critical sustainability challenges of the Anthropocene, including the climate emergency and biodiversity crisis. Mainstreaming NbS in professional practice requires strategic, landscape-level planning integrating multiple sources of benefits and their synergies and trade-offs. Levee setbacks (LS) are among the best-studied riverine NbS with recognized benefits for flood risk management, drought resilience, water quality management, recreational opportunities, and ecological restoration for biodiversity. Although awareness of the multifarious benefits of LS as forms of Natural Capital is growing, implementation remains ad-hoc and opportunistic. To address this critical implementation gap for one major example of NbS, we review and synthesize literature across diverse disciplines to provide an overview of the primary social, economic, and ecological mechanisms that affect the co-benefit delivery of LS projects. Next, to make this information relevant to NbS practitioners, we link these mechanisms to spatial metrics that can be used to approximate the relative magnitude of project benefits and costs across these mechanisms. Finally, we highlight examples of key synergies and trade-offs among benefits that should be considered for LS planning. This synthetic approach is intended to familiarize readers with the diverse potential benefits of LS, and provide an understanding of how to select and prioritize potential sites for further study and implementation. Synergies and trade-offs among important benefit drivers abound, and social equity concerns will be paramount in ensuring the successful implementation of LS and other NbS in the future.

22 Apr 2026

Juvenile Atlantic Sturgeon Survival and Movement in Proximity to an Active Cutterhead Suction Dredge

Abstract: The Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus has suffered population declines throughout its range. Many knowledge gaps exist regarding how to mitigate threats and better inform recovery efforts. This study examined survival of juveniles during their movements through river reaches undergoing channel maintenance dredging operations. During 2019 and 2020, 268 (30-71cm fork length) juvenile Atlantic Sturgeon were captured and released in proximity to an active cutterhead suction dredge at three sites within the James River, Virginia. Juveniles were captured, some presumed feeding, around 95-145m from the dredge in areas that could easily be avoided if the dredge created a stressful environment. No significant trends in catch-per-unit-effort were found when trawl catch was compared to a reference location or when monitoring gill net catch 100m down current of a dredge over a month-long period at one of the sites. Twenty-nine of the 229 gill net captures were implanted with acoustic tags and telemetry was used to track their movements throughout the river. Four telemetered juveniles tagged prior to this project were also detected moving within dredge operations. Cumulatively, tagged juveniles made at least 125 passes of the dredging operations with no evidence of mortality. All tagged juveniles still within the river were detected following the cessation of dredging. The results of this study support that age 1-2yr Atlantic Sturgeon show no avoidance behavior of areas 100m of an active cutterhead suction dredge and move past dredge operations with low-risk of mortality.

20 Apr 2026

Effects of Environmental Chemical Pollutants on Microbiome Diversity: Insights from Shotgun Metagenomics

Abstract: Chemical exposure in the environment can adversely affect the biodiversity of living organisms, particularly when persistent chemicals accumulate over time and disrupt the balance of microbial populations. In this study, we examined how chemical contaminants influence microorganisms in sediment and overlaying water samples collected from the Kinnickinnic, Milwaukee, and Menomonee Rivers near Milwaukee, Wisconsin, USA. We characterized these samples using shotgun metagenomic sequencing to assess micro-biome diversity and employed chemical analyses to quantify more than 200 compounds spanning 16 broad classes, including pesticides, industrial products, personal care products, and pharmaceuticals. Integrative and differential comparative analyses of the combined datasets revealed that microbial density, approximated by adjusted total sequence reads, declined with increasing total chemical concentrations. Protozoan, metazoan, and fun-gal populations were negatively correlated with higher chemical concentrations, whereas certain bacterial and archaeal populations showed positive correlations. As expected, sediment samples exhibited higher concentrations and a wider dynamic range of chemicals compared to water samples. Varying levels of chemical contamination appeared to shape the distribution of microbial taxa, with some bacterial, metazoan, and protozoan populations present only at certain sites or in specific sample types. These findings suggest that microbial diversity may be linked to both the type and concentration of chemicals present. Additionally, this study demonstrates the potential roles of multiple microbial kingdoms in degrading environmental pollutants, emphasizing the metabolic versatility of bacteria and archaea in processing complex contaminants such as polyaromatic hydrocarbons and bisphenols. Through functional and resistance gene profiling, we observed that multi-kingdom microbial consortia—including bacteria, fungi, and protozoa—can contribute to bioremediation strategies and help restore ecological balance in contaminated ecosystems. This approach may also serve as a valuable proxy for assessing the types and levels of chemical pollutants, as well as their effects on biodiversity.

14 Apr 2026

A Synthesis of Freshwater Forested Wetland Soil Organic Carbon Storage

Abstract: Freshwater forested wetlands account for ~76% of the total global wetland extent. However, freshwater forested wetlands are difficult to distinguish from upland forest due to canopy coverage, the abundance of wetland-nonwetland mosaics, seasonal hydropatterns, and fewer readily observable connections to large surface water bodies relative to marshes and other emergent habitats. Therefore, freshwater forested wetland ecosystems are often misclassified as upland forests in carbon accounting models, underestimating soil organic carbon storage. This study highlights freshwater forested wetland SOC accounting challenges and presents SOC densities/stocks from a global literature synthesis across different freshwater forested wetland types. We reviewed 374 forested wetland articles, compiling and calculating carbon densities by depth from 90 freshwater forested wetland studies to construct a database of 334 study sites including nine countries. The median SOC stock was 91.2 ± 46.4 Mg C ha−1 and 235.3 ± 125.6 Mg C ha−1 in the top 30 cm and 100 cm of soil, respectively. The tidal freshwater forested wetland had highest SOC stock in the upper 100 cm soil profile followed by rainforest, non-tidal swamps, and floodplain forested wetlands. Within the conterminous United States forest type groups, the Tsuga/Picea group had the highest median SOC stocks in the top 100 cm of soil followed by Quercus/Pinus and Quercus/Liquidambar/Taxodium groups, likely driven by variability in litter degradability, wetland hydroperiod, geomorphic positions, and regional climatic factors. This literature synthesis highlights SOC accounting in freshwater forested wetland carbon pools when estimating carbon stocks and fluxes. Results can be used to improve carbon modeling outcomes, as well as inform regional, national, and global management of wetland carbon resources.

13 Apr 2026

Review of Emerging and Nonconventional Analytical Techniques for Per- and Polyfluoroalkyl Substances (PFAS): Application for Risk Assessment

Abstract: Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that pose significant risks to ecosystems and human health. Increasing regulatory demands for PFAS management have increased the need for rapid and deployable analytical technologies for both abiotic and biotic matrices. Traditional detection methods, such as standardized chromatography, often require weeks to months for analysis due to a limited number of appropriately accredited laboratories, delaying critical decision-making. This literature review is intended to identify promising emerging PFAS analytical techniques or technologies to facilitate more rapid (near real-time) analysis and explore their relevancy in supporting human and ecological risk assessments. Recently developed optical and electrochemical sensing approaches are enabling the detection of PFASs within minutes to hours, with detection limits typically aligning within reported ambient concentrations in water, soil, and sediment. These emerging technologies could (1) support planning and prioritization of sampling efforts during the problem formulation phase of risk assessment, (2) complement traditional chromatography methods to lower time and resource demands to improve sampling frequency over space and time, and (3) aid in risk-informed characterization of PFAS exposures based on identified chemical classes or groups. This review highlights those approaches and technologies that could potentially enhance the comprehensiveness and efficiency of PFAS risk assessment across diverse environmental settings in the future.

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.