27 Aug 2025

Evaluating Transport of Stockpiled Mississippi River System Sand for Beach Nourishment and Other Uses

The US Army Corps of Engineers (USACE), Rock Island and St. Paul Districts, maintain 876 miles of shallow-draft navigation channels, dredging approximately 2 million cubic yards of clean, fine- to medium-grained sands from these waterways annually. Due to system constraints and certain state regulatory policies, most of this dredged material (DM) is placed in upland and island facilities. As these dredge placement areas fill with sediment, the districts need to remove sediment to create additional storage or seek new land acquisition. While a significant amount of this DM is being locally used beneficially, the current uses are opportunity driven and dictated by proximity. As such, the districts continue to seek alternative beneficial use practices. One major limiting factor to increased beneficial use is the cost of material transport. Per the Federal Standard, USACE will use the least costly DM placement alternatives that are consistent with sound engineering practices and meet federal environmental requirements. Transport beyond traditional placement sites typically costs much more. The analysis described in this report reviews nontraditional transportation modes and routes to match distant needs with river sediment.

27 Aug 2025

Methods for 3D Printing Dredge Sediments to Sequester Contaminants

Purpose: This technical note describes methods for preparing dredged sediment and commercially available clay for 3D printing, focusing on achieving optimal consistency and properties for successful extrusion. These methods establish best practices for using dredged sediments in 3D printing applications.

27 Aug 2025

Demonstration of a Remotely Operated Vehicle for Inspecting the Chicago Electrical Fish Dispersal Barrier

Purpose: This report describes the US Army Engineer Research and Development Center (ERDC) application of a remotely operated vehicle to inspect an electrical fish dispersal barrier at the bottom of the Chicago Sanitary Ship Canal (CSSC) for the US Army Corps of Engineers–Chicago District.

22 Aug 2025

Cracking the Code: Linking Good Modeling and Coding Practices for New Ecological Modelers

Abstract: Good modeling practices are essential for producing reliable and reproducible ecological models. Inherent to good modeling practices are fundamental coding and documentation skills, which not only implement the desired modeling capabilities but also clearly outline the goals, methods, and components of a model necessary to reproduce desired results. Coding represents a significant barrier for entry into ecological modeling, since most ecologists have not had formal training in computer science or software development. While software packages do exist that facilitate model development, we have observed that newer modelers still struggle with developing good coding practice throughout the modeling process. During a series of agent-based modeling short-courses and full semester graduate courses, both taught in NetLogo, we identified some common challenges encountered by graduate students and environmental professionals as they learn to code an ecological model, many for the first time. We were able to categorize and provide examples of the main challenges and obstacles, which fell into three main groups that follow the steps of good modeling practice: problem scoping and conceptualization, formulation, and evaluation. We then provide guidance on how to overcome these obstacles while developing good coding and modeling practices that will result in more scientifically defensible models.

20 Aug 2025

Trade-offs Between Field and Remote Geomorphic Monitoring of Coastal Marsh Restoration Sites

Abstract: Coastal marsh restoration presents geomorphic monitoring challenges because these sites are often remote or inaccessible, and time and financial resources for field data may be limited. Yet, elevation and shoreline characteristics contribute to the overall health and longevity of coastal marshes. The expansion of Uncrewed Aircraft System (UAS) technology and new satellite platforms offer opportunities to complement ground-based geomorphic monitoring and overcome the challenges of traditional field methods. Here, we compare field-based and remote-sensing approaches to monitor two restored coastal wetlands in Louisiana. At Spanish Pass, methods for measuring site elevation, shoreline position, and shoreline geomorphic types were compared. Ground surveys strongly correlated with UAS-lidar digital elevation model (DEM) elevations (R2 = 0.97. UAS and satellite imagery were accurate to within 3 meters of field-shoreline positions, and UAS-lidar-derived shorelines had the lowest error. At LaBranche, UAS-lidar DEM data were paired with airborne lidar and legacy ground surveys to track temporal changes in elevation, indicating minimal elevation change. The study demonstrates the accuracy and utility of satellite and UAS remote sensing for monitoring shoreline positions and elevations but notes that shoreline classifications could be improved with additional quantification. These findings help practitioners assess the trade-offs and benefits of various monitoring methods.

19 Aug 2025

Bioaccumulation in Fish (Cyprinodon variegatus) During Rejuvenations of a Thin Active Cap over Field-Aged PCB Contaminated Sediment: The Effect of Clean Versus Contaminated Ongoing Influx

Abstract: Repeated addition of activated carbon (AC) via the water column was applied to rejuvenate sorption capacity of thin AC-amended sand caps placed over polychlorinated biphenyl- (PCB) contaminated marine bed sediment receiving ongoing input of sediment (contaminated or clean) in mesocosms. Bioaccumulation of PCBs in sheepshead minnows (Cyprinodon variegatus) from bed sediment was reduced by repeated application of reju-venating AC when the ongoing input was contaminated. However, when the input sediment was clean, the novel AC addition increased fish uptake of bedded PCBs in the first 60-days of the 90-day experiments. The 79 % increase of bedded PCB bioaccumulation in fish, for clean versus contaminated inputs, was statistically signifi-cant (p < 0.05) in experiments where the rejuvenating AC was applied. Equilibrium concentrations in low- density polyethylene (LDPE) passive samplers did not fully explain bioaccumulation. Field implications of this research include setting appropriate temporal expectations of this novel remediation strategy regarding the primary desired effect (i.e., PCB bioavailability reductions).

19 Aug 2025

Cooperative Molecular Interaction-Based Highly Efficient Capturing of Ultrashort- and Short-Chain Emerging Per- and Polyfluoroalkyl Substances Using Multifunctional Nanoadsorbents

Abstract: The short-chain and ultrashort-chain per- and polyfluoroalkyl substances are bioaccumulative, carcinogenic to humans, and harder to remove using current technologies. Herein, we report the development of nonafluorobutane-sulfonyl and polyethylene-imine -conjugated Fe3O4 magnetic nanoparticle-based magnetic nanoadsorbents and demonstrated the novel adsorbent has the capability for highly efficient removal of six different short- and ultrashort-chain PFAS from drinking and environmental water samples. Reported experimental data indicates by capitalizing the cooperative hydrophobic, fluorophilic, and electrostatic interaction processes, NFBS-PEI-conjugated magnetic nanoadsorbents can remove ~100% short-chain perfluorobutanesulfonic acid within 30 min from the water sample with a maximum absorption capacity qm of ~234 mg g−1. Furthermore, to show how cooperative interactions are necessary for effective capturing of ultrashort and short PFAS, a comparative study has been performed using PEI-attached magnetic nanoadsorbents without NFBS and acid-functionalized magnetic nanoadsorbents without PEI and NFBS. Reported data show the ultrashort-chain perfluoropropanesulfonic acid capture efficiency is the highest for the NFBS-PEI-attached nanoadsorbent. Moreover, reported data demonstrate that nanoadsorbents can be used for effective removal of short-chain PFAS and ultrashort-chain PFAS simultaneously from reservoir, lake, tape, and river water samples within 30 min, which shows the potential of nanoadsorbents for real-life PFAS remediation.

18 Aug 2025

Archaeogenomic Analysis of Chesapeake Atlantic Sturgeon Illustrates Shaping of Its Populations in Recovery from Severe Overexploitation

Abstract: Atlantic sturgeon (Acipenser oxyrinchus ssp. oxyrinchus) has been a food resource in North America for millennia. However, industrial-scale fishing activities following the establishment of European colonies led to multiple collapses of sturgeon stocks, driving populations such as those in the Chesapeake area close to extinction. While recent conservation efforts have been successful in restoring census numbers, little is known regarding genomic consequences of the population bottleneck. Here, we characterize its effect on present-day population structuring and genomic diversity in James River populations. To establish a pre-collapse baseline, we collected genomic data from archaeological remains from Middle Woodland Maycock’s Point (c. 200–900 CE), as well as Jamestown and Williamsburg colonial sites. Demographic analysis of recovered mitogenomes reveals a historical collapse in effective population size, also reflected in diminished present-day mitogenomic diversity and structure. We infer that James River fall- and spring-spawning populations likely took shape in recent years of population recovery, where genetic drift enhanced the degree of population structure. The mismatch of mitogenomic lineages to geographical–seasonal groupings implies that despite their homing instinct and differential adaptation manifested as season-specific behaviour, colonization of new rivers has been a key ecological strategy for Atlantic sturgeon over evolutionary timescales.

18 Aug 2025

Coastal Environments: LiDAR Mapping of Copper Tailings Impacts, Particle Retention of Copper, Leaching, and Toxicity

Abstract: Tailings generated by mining account for the largest world-wide waste from industrial activities. Copper is relatively uncommon, with low concentrations in sediments and waters, yet is very elevated around mining operations. On the Keweenaw Peninsula, 140 mines extracted native copper from the Portage Lake Volcanic Series, part of an intercontinental rift system. Between 1901 and 1932, two mills at Gay sluiced 22.7 million metric tonnes of copper-rich tailings into Grand Traverse Bay. About 10 MMT formed a beach which migrated 7 km to the Traverse River Seawall. Another 11 MMT are moving underwater along the coastal shelf, threatening Buffalo Reef. Remote sensing techniques documented geospatial environmental impacts and initial phases of remediation. Aerial photos, ALS LiDAR/MSS surveys, and recent UAS overflights aid comprehensive mapping efforts. Because natural beach quartz and basalt stamp sands are silicates of similar size and density, percentage stamp sand determinations utilise microscopic procedures. Copper leaching is elevated by exposure to high DOC and low pH waters, characteristic of riparian environments. Lab and field toxicity experiments, plus benthic sampling, all confirm serious impacts of tailings on aquatic organisms. Mining companies should end coastal discharges and also adopt the UNEP “Global Tailings Management Standard for the Mining Industry”.

18 Aug 2025

Cell-Penetrating Peptide-Mediated Delivery of Gene-Silencing Nucleic Acids to the Invasive Common Reed Phragmites australis via Foliar Application

Abstract: RNA interference-based gene silencing has been increasingly explored for potential applications to control invasive species. At least two major hurdles exist when applying this approach to invasive plants: (1) the design and screening of species- and gene-specific biomacromolecules made of DNA, RNA, or peptides that can suppress the expression of target genes efficiently, and (2) the delivery vehicle needed to penetrate plant cell walls and other physical barriers. In this study, we investigated the cell-penetrating peptide-mediated delivery of multiple types of GSAs to knock down a putative phytoene desaturase gene in the invasive common reed. Both microscopic and quantitative gene expression evidence demonstrated the CPP-mediated internalization of GSA cargos and transient suppression of PDS expression in both treated and systemic leaves up to 7 days post foliar application. Although various GSA combinations and application rates and frequencies were tested, we observed limitations, including low gene-silencing efficiency and a lack of physiological trait alteration, likely owing to low CPP payload capacity and the incomplete characterization of the PDS-coding genes in P. australis. Our work lays a foundation to support further research toward the development of convenient, cost-effective, field-deployable, and environmentally benign gene-silencing technologies for invasive P. australis management.