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.

13 Aug 2025

Examination of Activated Carbon Losses During Open Water Placement of Amended Dredged Material for Bioaccumulation Control

Purpose: The purpose of this study was to evaluate the potential losses of both powdered and granular activated carbon (AC) resulting from open water placement of AC-amended dredged material to reduce contaminant bioaccumulation. The study examined the results of model predictions, a laboratory dump test, and a field demonstration project performed at the Ashtabula Lake Erie placement site.

12 Aug 2025

Applying the Working with Nature Philosophy to Navigation Infrastructure Projects

Abstract: In 2008, the World Association for Waterborne Transport Infrastructure published a position paper describing a Working with Nature philosophy aimed to change how the sector approaches navigation and port infrastructure projects. In 2018, Pianc published guidance on implementing WwN. Pianc’s guidance presents a six-step process that encourages consideration of site-specific ecosystem characteristics and WwN opportunities at early stages of project development, early stakeholder engagement and integration of WwN into the development of project objectives before design begins. By incorporating WwN applications during conception, the WwN approach provides the most promising opportunities to affect positive outcomes for the environment. This holistic understanding of ecosystem processes and socioeconomic interactions realises environmental impacts can be minimised while concomitantly seeking opportunities to enhance ecosystem functions at various spatial and temporal scales. Project delivery thus goes beyond avoiding or compensating for negative project impacts and seeks multi-sector ecosystem and socioeconomic benefits. Applied in practice, WwN can increase habitat functionality, reduce energy associated with construction or maintenance, and enhance the short- and long-term delivery of ecosystem services. Projects consistent with the WwN philosophy achieve their underlying engineering objectives, alongside various co-benefits, consistent with the environmental, societal and economic sustainability pillars.

7 Aug 2025

Financing Natural Infrastructure: Lightning Point, Alabama

Purpose: This technical note explores the restoration of Lightning Point, an award-winning natural infrastructure project led by The Nature Conservancy (TNC) in coastal Alabama. The story of Lightning Point provides an exemplar case study of successful coordination of cross-sector partnerships and the use of ecosystem services valuation to attract project funding.

7 Aug 2025

Continued Development of Methods for the Determination of Legacy and Insensitive Munitions from Environmental Matrices: Addition of Four Degradation Products and One Internal Standard to Previously Developed 29-Analyte Method

Abstract: To continue improving separation methods of explosive analytes and their degradation products, chromatographic methods from Environmental Protection Agency (EPA) 8330B, Strategic Environmental Research and Development Program (SERDP) 2722, and Environmental Sensors for Explosives were modified to include the separation of four additional analytes and one internal standard so that a total of 36 analytes could be resolved on a single column. Four degradation compounds, 3-amino-1,2,4-triazol-5-one (ATO); 1 methyl-3-nitroguandine (MeNQ); 2 methoxy-5-nitroaniline (MENA); and 4 methoxy-3-nitroaniline (iMENA) were added to the analytical method. The internal standard, 3,5-dinitrotoluene, was also added to the method to extend its application. Additionally, an analytical method on gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS) were explored for the analytes of interest.

7 Aug 2025

Thermodynamic Exposure Reductions of PCBs Available to Lumbriculus variegatus in Lake Erie Region Sediments Amended with Activated Carbon

Abstract: A chemical activity-based assessment of PCB bioaccumulation from Lake Erie region sediments was studied using polydimethylsiloxane coated fibers and Dow Corning silicone coated jars. Polymers equilibrated with the sediments were compared to bioaccumulation in blackworms, exposed to the sediments for 28 days. Sediments were from Cleveland Harbor, Ashtabula Harbor, and Buffalo River. Sediment from Ashtabula was amended with activated carbon. Using lipid-polymer partition coefficients, the polymers were able to estimate actual bioaccumulation in worms, with close to a 1:1 relationship and r2 = 0.94. If lipid normalized worm bioaccumulation was compared to equilibrated PDMS concentrations, there was a 20:1 ‘off-set,’ but the relation was still strong. Different doses of AC were mixed into Ashtabula sediment in the laboratory, corresponding to 1 %, 10 %, and 100 % of the native total organic carbon. Based on PCB concentrations in DC silicone, a target AC dose equal to 10 % of the TOC would substantially reduce bioaccumulation of the more hydrophobic PCBs from Ashtabula Harbor dredged material. Widespread AC amendment to surficial sediment of the eastern basin of Lake Erie may reduce the thermodynamic pressure of PCBs from that sediment source and allow for a continued decline in fish tissue concentrations.

4 Aug 2025

Acoustic and Seismic Wave Transmission Throughout the Multidomain Environment: Experimental Design, Methods, and Construction of a Prototypical Littoral Zone

Abstract: The future operational environment is projected to be a multidomain, transparent battlefield in which the Army must be able to act as both a supported and supporting force. An accurate detection and interpretation of acoustic and seismic signals propagating across land-air-water (LAW) interfaces are required to meet future requirements of a fully “transparent” domain. The LAW domains converge at the significant contested littoral zones. Historically, interpreting signals crossing media boundaries has been studied by stovepiping each distinct medium. These fragmented perspectives led to discrepancies in boundary and adjacent media descriptions and media-specific governing physics. No comprehensive physics framework exists to accurately predict how disorderly waveforms freely traverse LAW media boundaries. To understand these complex phenomena, a highly controlled physical experiment was designed and implemented. Repeatable controls were conducted. Epistemic uncertainty was decreased, and high waveform fidelity was maintained in the experimental setup by not interfering with wave transmission or sensor accuracy between controls. This report summarizes the experimental design, implementation, challenges, and repeatability.

29 Jul 2025

Engineering Practice Guide for Floodplain Benching: A Natural Infrastructure Approach for Riverine Systems

Abstract: Floodplain benches are a potential solution for inland river systems where out-of-bank flooding generates unacceptable flood risk and access to riverine floodplains has become restricted over time. Benches are a naturally forming geomorphic feature between the riverbed and a higher floodplain or terrace. In addition to reducing flood risk, benches reduce erosion risk, improve aquatic ecosystems, enhance plant and wildlife diversity, expand recreational opportunities, and may be places of cultural and tribal value. This document informs engineering activities related to site investigation and design of floodplain benches. It is intended to be used by engineers and ecologists to inform the design of floodplain benches in a manner that is consistent with and augments other planning, design, and engineering guidance. A well-designed floodplain bench can improve ecological and biological functions while also reducing flood risk by creating a channel in geomorphic equilibrium with current conditions and resilience to anticipated changes in hydrology and sediment supply rates. This publication is among a series of planned technical reports providing guidance on how to identify, conceptualize, and design natural infrastructure solutions for riverine and coastal systems. It has been produced by the US Army Corps of Engineers (USACE) Engineering With Nature® Program.