12 Aug 2026

Toxicity of Per- and Polyfluoroalkyl Substances in Elutriates Prepared with Estuarine and Freshwater Sediments

Abstract: PFAS has a ubiquitous environmental occurrence, posing challenges to sediment management. To address data gaps concerning release of PFAS from sediment to the water column during dredged material aquatic placement or other sediment resuspension activity, we generated elutriates from PFAS-contaminated sediments. Sediments were obtained from both freshwater and estuarine environments, with a field-collected sediment representative of contaminated areas and a spiked sediment with concentrations exceeding levels frequently measured at contaminated sites. We then conducted acute toxicity tests of the elutriates with species standardly used in dredging evaluations: the sheepshead minnow (Cyprinodon variegatus), the fathead minnow (Pimephales promelas), the water flea (Ceriodaphnia dubia), and the Mysid shrimp (Americamysis bahia). PFAS partitioning to sediment and organic matter was observed to increase with carbon chain length. PFAS-induced mortality was not observed in any of the four test species, as measured concentrations of PFAS were below levels known to cause negative effects in these organisms. Though PFAS concentrations in the spiked sediment elutriates exceeded concentrations known to cause effects in the most sensitive aquatic species, PFAS levels in the more environmentally relevant field-collected sediment elutriates did not. Consequently, PFAS released from the sediment to the water column is not expected to cause toxicity to pelagic biota during aquatic placement of dredged material.

12 Aug 2026

Introduction of Three Cryptic Lineages of Invasive Crested Floating Heart (Nymphoides cristata) in the Southeastern United States

Abstract: Crested floating heart [Nymphoides cristata (Roxb.) Kuntze] is an invasive aquatic plant in the southeastern United States. For clonal plants like N. cristata, clonal diversity may influence response to control tactics and/or evolutionary potential. However, little is known about the diversity of introduced N. cristata. In this study, we used genotyping by sequencing to quantify N. cristata diversity in the southeastern United States and determine how that diversity is distributed across the invaded range. Our results show that at least three distinct genetic lineages of N. cristata are present in the southeastern United States. Geographic distribution of the lineages varied, with one widespread lineage identified across several states and others only found in a single water body. There is also evidence of extensive asexual reproduction, with invaded water bodies often host to a single genetic lineage. The genetic diversity reported in this study likely results from multiple introductions of N. cristata to the southeastern United States and should be considered by managers when assessing control tactics, such as screening for biocontrol agents or herbicide testing. The extent and distribution of genetic diversity should also be considered by researchers studying the potential for invasive spread of N. cristata within the United States or hybridization with native Nymphoides species.

11 Aug 2026

Eight Recommendations to Enhance Biodiversity Outcomes of Nature-Based Solutions at Multiple Scales

Abstract: Ambitions to mainstream Nature-based Solutions (NbS) and achieve global implementation are hampered by the lack of transdisciplinary integration across disciplines and practice. Ecological knowledge, including an under-standing of how biodiversity can support, and be supported by, NbS design and implementation remains an under-studied component of the NbS concept despite its critical importance. Starting with a brief primer on the major roles that biodiversity plays in NbS performance, we present eight recommendations for enhancing biodiversity in NbS planning and implementation. This narrative expert synthesis draws from an interdisciplinary literature search and decades of experience across landscape ecology, environmental engineering, urban planning, wildlife management, ecological restoration, and conservation science. Recommendations emphasize the importance of considering the ecological mechanisms that support biodiversity (i.e., viable populations of coexisting species) and understanding the role of organismal life history, species interactions, habitat preferences, and metapopulation dynamics in determining NbS features’ ecological resilience and contributions to biodiversity enhancement (i.e., IUCN Global Standard Criterion 3). We also emphasize the importance of assessing biodiversity across spatial scales and dimensions (e.g., functional, phylogenetic) and monitoring and ecological management for anticipating and adapting to unexpected outcomes, invasive species, and ecosystem dis-services. This review is intended to increase connections between ecological science, conservation biology, and NbS implementation to support more biodiverse projects with more robust, resilient, and multifunctional performance and greater contributions to global conservation.

11 Aug 2026

Continental-scale mapping of forest tree density in North America using remote sensing and deep learning with uncertainty quantification

Abstract: Accurate, spatially consistent estimates of tree density remain elusive at continental scales, limiting our ability to assess forest structure, carbon stocks, and biodiversity. Existing global assessments have relied on simplified statistical models and sparse, heterogeneous ground data that are insufficient to capture nonlinear ecological interactions and spatial variability. To address these limitations, we integrated more than 600,000 harmonized ground-based forest inventory plots with satellite-derived vegetation indices, climate surfaces, soil properties, and topographic covariates to develop a deep learning framework for high-resolution mapping of tree density across North America. We evaluated four modeling approaches—generalized linear models, ridge regression, random forest, and a feedforward neural network. Among all models tested, the FFNN achieved the highest predictive accuracy, and was used to produce a wall-to-wall tree density map at 3 km resolution for the continent. We estimated that the total number of forest trees with diameter at breast height ≥ 10 cm across North America ranges from 339 to 514 billion, substantially lower than the widely cited estimate of 603 billion trees reported by Crowther et al. (2015). When smaller stems were included, totals more than doubled, reaching 738 billion to 1.12 trillion trees. We quantified uncertainty using Monte Carlo Dropout, generating pixel-level error estimates and confidence intervals. Spatial patterns reveal high tree densities in boreal and temperate forests, intermediate densities in mixed broadleaf regions, and relatively low densities in deserts, Mediterranean systems, and tundra. Compared to the global GLM-based benchmark by Crowther et al. (2015), our deep learning framework achieves markedly higher predictive accuracy, aligns more closely with national forest inventory statistics, and provides explicit uncertainty quantification, supporting applications in carbon accounting, biodiversity modeling, and ecosystem monitoring at scales through region specific calibration and validation.

11 Aug 2026

Establishing Native Submersed Aquatic Vegetation at Times Beach, Buffalo, New York

Purpose: Establishing native submersed aquatic vegetation (SAV) in reservoirs, lakes, and ponds involves several considerations, including sources and types of transplant propagules, fluctuating water levels, and herbivory (Smart et al. 1998). Over the past 20 years, US Army Engineer Research and Development Center (ERDC) Environmental Lab researchers have developed methods for establishing native SAV that address these issues. While consistently and successfully applied in the southern United States (Dick et al. 2005), their applicability to northern waterbodies remains untested. This two-part demonstration study evaluated several SAV establishment techniques in a constructed wetland adjacent to Lake Erie, Buffalo, New York.

21 Jul 2026

Demonstration Validation of Air Supercritical Water Oxidation (AirSCWO 6) PFAS Destruction: Aqueous Film-Forming Foam Treatment by 374Water AirSCWO Technology

Abstract: The Department of Defense (DoD) faces significant environmental challenges regarding the disposal of legacy aqueous film-forming foam (AFFF) containing persistent PFAS. This project, led by the US Army Engineer Re-search and Development Center (ERDC), evaluates the performance of the 374Water AirSCWO™ 6 system in destroying PFAS within AFFF. During the demonstration, 100 gal. of AFFF were treated, successfully meeting US EPA maximum contaminant levels (MCLs) for PFAS in the liquid effluent. The system achieved a destruction removal efficiency of 99.9993% for total PFAS as analyzed via the total oxidizable precursor (TOP) Assay (42 PFAS). Stack emissions remained below 500 g/h for vola-tile fluorinated compounds as measured by Other Test Method (OTM)–50. While the demister condensate exceeded US EPA PFAS MCLs, the total volume was negligible at less than 0.5 L. Energy efficiency analysis showed a consumption of 1.15 MWh per cubic meter of AFFF per order of magnitude of 42 PFAS destroyed and 12.9 kWh per gram of PFAS destroyed. Treatment costs varied and may range from $47 to $238 per gallon of AFFF. These results demonstrate the effectiveness of super-critical water oxidation technology for a safer disposal of legacy AFFF concentrates.

17 Jul 2026

Improved Beneficial Use of Dredged Material (BUDM) Laboratory Methods for Low-Stress Consolidation

Abstract: The purpose of this Dredging Operations and Environmental Research (DOER) Program technical note (TN) is to present the improved laboratory methods for low-stress consolidation to support the beneficial use of dredged material (BUDM). Despite the growing practice of BUDM to support coastal environments, significant knowledge gaps persist in the behavior (e.g., consolidation and erodibility) of hydraulically placed cohesive sediments. The consolidation of deposited sediment dictates the resultant surface elevation, a key design component controlling the hydroperiod and shear strength of wetland ecosystems, which are key indicators of the long-term health and stability of the wetland. The existing US Army Corps of Engineers (USACE) consolidation testing of ultrasoft materials utilizes settling columns that rely on highly time-consuming, experimental laboratory methods that are prone to human-induced errors. Therefore, an updated laboratory methodology that incorporates scientific advancements to manage consolidation and erodibility measurements is essential to providing practical testing with a higher degree of certainty for BUDM designers and ultimately helping to support USACE’s goal of reaching 70% BUDM.

17 Jul 2026

Application of GPS/GSM (Global System for Mobile Communications) Tag Technology to Investigate Seasonal Habitat Use by a Coastal Bird: A Pilot Study Using the Royal Tern (Thalasseus maximus)

Purpose: This technical note was developed by personnel from the US Army Engineer Research and Development Center–Environmental Laboratory (ERDC-EL) to describe the application of GPS/GSM (Global System for Mobile Communications) technology to wildlife studies to assess the effects of coastal engineering operations. GPS/GSM tags utilize cell tower transmissions to accurately locate animal positions in the landscape. While some satellite-based wildlife tags use Doppler technology, the GPS/GSM tags rely on GPS-based technology, which improves level position accuracy (e.g., ±30 m GPS/GSM tags versus ±300 m Doppler tags) in the landscape.* Doppler satellite tags break down distance accuracy into six location categories that range from ≤150 m to over 1,000 m, with a general average location accuracy of ≥300 m. The level of position accuracy with GPS/GSM tag technology permits researchers to determine if tagged birds are utilizing recently engineered coastal habitats (e.g., renourished beaches, dredged material islands, and restored wetlands), natural habitats, or minimally engineered coastal habitats. GPS/GSM tags could also be used to assess the frequency and seasonal changes of habitat use. Many coastal birds are known to breed on coastal dredged-material islands, often in response to coastal habitat loss wrought by dredging operations and other engineering actions (Soots and Landin 1978). In these same coastal areas, habitat degradation can occur through increased erosion and increased storm frequency and severity. The resulting habitat loss contributes to observed declines in coastal bird populations (Iglecia and Winn 2021; Newton 2004). These long-term population declines are not solely affecting coastal breeding species (Rosenberg et al. 2016). Habitat loss and population declines are also affecting many long-distance migrants that are seasonally transient and, thus, found along coastal habitats of the conterminous United States (Winn et al. 2013). The federally threatened Red Knot (Calidris canutus) is an example of a coastal transient species. Numerous other coastal birds currently experiencing population declines are potential candidates for future federal listing (Winn et al. 2013; Iglecia and Winn 2021). Interestingly, survey data suggested the Snowy Plover (Charadrius nivosus) avoids beaches that have been subjected to renourishment (Lott 2009; Lott and Fischer 2011), indicating that there may be variable, species-specific seasonal responses to coastal engineered habitats that remain poorly understood for many coastal birds. Therefore, there is a growing interest in determining the seasonal habitat needs of resident and migrant coastal birds and in approaches to beneficial uses of dredged material (BUDM) that could be used to design and construct year-round habitats (Guilfoyle et al. 2019, 2024).* However, much more research is required to determine the basic ecology, seasonal distribution, and seasonal habitat requirements of North American coastal birds to facilitate improved coastal habitat restoration and conservation. This technical note describes a pilot study in which 10 GPS/GSM tags were affixed to breeding Royal Terns (Thalasseus maximus; Figure 1) captured on South Island of the Hampton Roads Bridge-Tunnel in coastal Virginia. This study was part of a larger project to compile best management practices (Guilfoyle et al. 2019) and suggested management strategies† and was funded through the Ecosystem Management and Restoration Research Program (EMRRP). The Royal Tern was selected for this effort due to its relatively large size, which was suitable for a GPS/GSM tag, its known dependence on dredged-material islands for breeding, and its use of open beach habitats in the Southeastern United States and along the Gulf Coast during the wintering season.

7 Jul 2026

FIMOFs: Fiber-Integrated Metal–Organic Frameworks through Electrospinning

Abstract: Green synthesis plays a crucial role in advancing sustainability within materials science. This study explores the integration of metal–organic frameworks (MOFs), obtained through green synthesis, using an electrospinning post-processing technique to develop MOF-based composite materials. The resulting novel multifunctional composites demonstrate enhanced stability and functionality, compared to their control counterparts. The integration of four types of MOFs into an electrospun fiber network was investigated using a specific polymer solution. Characterization and preliminary adsorption studies were conducted to elucidate the chemistry, morphology, and adsorptive capabilities of the resulting MOF composites. Electrospinning MOFs into polymer fibers improved their stability and dye removal capabilities. More specifically, optimization of MOF-to-polymer ratios and processing conditions yielded composites that are thermally stable, with modified surface area and porosity. Post-processing MOFs resulted in a fiber diameter increase of 44 and 109%, enhancing the composites by providing more MOF active sites and improved mechanical strength. Zirconium-based post-processed MOFs demonstrated superior dye removal, different from the copper-based dyes. Electrospinning technology has demonstrated significant potential in the fabrication of high-performance multifunctional MOF composites. This has helped to create advanced sustainable composites with tailored properties, paving the way for more targeted and efficient applications. The applications of these composites show promise for military engineering where durable, light weight, and multifunctional materials are critical in contributing to improved performance, operational efficiency, and safety.

29 Jun 2026

Evaluation of Water Hyacinth (Eichhornia Crassipes) Response to Herbicides Using Unmanned Aerial System Imagery

Abstract: Water hyacinth is a highly invasive aquatic species in the southern United States that requires intensive management through frequent herbicide applications. Quantifying management success in large-scale operations is challenging with traditional survey methods that rely on boat-based teams and can be time-consuming and labor-intensive. In contrast, an unmanned aerial system (UAS) allows a single operator to survey a waterbody more efficiently and rapidly, enhancing both coverage and data collection. Therefore, the objective of this research was to develop remote sensing techniques to assess herbicide efficacy for water hyacinth control in an outdoor mesocosm study. Experiments were conducted in spring and summer 2023 to compare and correlate data from visual evaluations of herbicide efficacy against nine vegetation indices (VIs) derived from UAS-based red-green-blue imagery. Penoxsulam, carfentrazone, diquat, 2,4-D, florpyrauxifen-benzyl, and glyphosate were applied at two rates, and experimental units were evaluated for 6 wk. The carotenoid reflectance index (CRI) had the highest Spearman’s correlation coefficient with visually evaluated efficacy for 2,4-D, diquat, and florpyrauxifen benzyl (> −0.77). The visible atmospherically resistance index (VARI) had the highest correlation with carfentrazone and penoxsulam treatments (> −0.70), and the excess greenness minus redness index had the highest correlation for glyphosate treatments (> −0.83). CRI had the highest correlation coefficient with the most herbicide treatments, and it was the only VI tested that did not include the red band. These VIs were satisfactory predictors of mid-range visually evaluated herbicide efficacy values but were poorly correlated with extremely low and high values, corresponding to nontreated and necrotic plants. Future research should focus on applying findings to real-world (nonexperimental) field conditions and testing imagery with spectral bands beyond the visible range.