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USGS2028

Migration ecology and stopover population size of Red Knots Calidris canutus rufa at Mingan Archipelago after exiting the breeding grounds

Populations of migratory birds present unique conservation challenges given the often vast distances separating critical resources throughout the annual cycle. Migration areas close to the breeding grounds represent a link between two key stages of the annual cycle, and understanding migration ecology as birds exit the breeding grounds may be particularly informative for successful conservation. We studied migration phenology and stopover ecology of an endangered subspecies of the Red Knot Calidris canutus rufa at a migration area relatively close to its breeding range. Using mark-recapture/resight data and a Jolly-Seber model for open populations, we described the arrival and departure schedules, stopover duration, and passage population size at the Mingan Archipelago, Quebec, Canada. Red Knots arrived at the study area in two distinct waves of birds separated by approximately 22 days. Nearly 30% of the passage population arrived in the first wave of arrivals during 15–18 July, and approximately 22% arrived in a second wave during 8–11 August. The sex-ratio in the stopover population at the time of the first wave was slightly skewed toward females, whereas the second wave was heavily skewed toward males. Because males remain on the breeding grounds to care for young, this may reflect successful breeding in the year of our study. The estimated stopover duration (population mean) was 11 days (95% credible interval: 10.3–11.7 days), but stopover persistence was variable throughout the season. We estimated a passage population size of 9,450 birds (8,355–10,710), a minimum estimate for reasons related to the duration of our sampling. Mingan Archipelago is thus an important migration area for this endangered subspecies and could be a priority in conservation planning. Our results also emphasize the advantages of mark-recapture/resight approaches for estimating migration phenology and stopover persistence.

Quebec↗
USGS2027

Ground failure resulting from earthquake ground motions

The ground failure resulting from an earthquake, at all scales, is ultimately controlled by the details of near-surface earthquake ground motions, the spatially distributed mechanical characteristics of surface materials and how the two interact. This chapter introduces the aspects of ground-motion seismology that are most relevant to the triggering of different types of ground failure, such as landslides and liquefaction. In particular, the chapter focuses on different sources of local modification (e.g. amplification) of earthquake ground motions in the shallow subsurface, known as site effects. The chapter ends with an overview of the controls on, general spatial patterns of, and approaches to regional modelling of the manifestation of ground failure that may be triggered by an earthquake.

Book chapter↗
USGS2026

Analysis of groundwater geochemistry in the Lansing, Michigan, area

Groundwater resources in the Lansing, Michigan, area are protected by a wellhead protection plan, but previous studies have indicated that groundwater in this area may be susceptible to surface contamination. The U.S. Geological Survey, in cooperation with the Lansing Board of Water & Light, analyzed geochemical and aquifer characteristics to assess the potential for contamination of groundwater resources. Recharge age categories were determined from tritium concentrations for some wells, and by using ternary diagrams and principal component analysis for other wells. These age classifications, combined with hydrogeologic and geochemical data, were analyzed by using statistical methods to identify trends that may indicate areas of increased groundwater susceptibility. Wells with modern recharge tended to have higher sodium, chloride, and chloride:bromide ratios than did wells with mixed recharge, suggesting greater surface connectivity and potential influence from anthropogenic sources such as road salt. In contrast, wells in the mixed age category exhibited more stable geochemistry and lower constituent concentrations. Classification and regression tree models identified aquifer geometry—particularly the thickness of the uppermost bedrock unit and presence of confining layers—as key predictors of recharge age and geochemical indicators. The trends identified from these analyses could help to reveal locations in the Lansing area that are among the most susceptible to contamination.

Scientific Investigations Report↗
USGS2026

Abundance estimates for a remnant population of extirpated Lake Erie cisco Coregonus artedi (albus) in Crystal Lake, Pennsylvania

The discovery of a remnant Lake Erie cisco ( Coregonus artedi “ albus ”) population in Crystal Lake, Pennsylvania provides a unique opportunity to evaluate the status of a fish that was extirpated, with the possibility that the unique Lake Erie form was extinct. Historically, Lake Erie cisco supported the largest freshwater fishery in the world, with annual harvests exceeding 22 million kilograms — nearly equivalent to the contemporary commercial harvest of all fish species in all of the Great Lakes, combined. The loss of the ecologically and economically important albus cisco has been a major impediment to restoring native coregonine diversity and food-web function in Lake Erie. To assess this remnant population, we integrated nighttime split-beam hydroacoustic surveys with daytime remotely operated vehicle (ROV) videography during stratification to estimate abundance and characterize habitat use by cisco. Hydroacoustic detections were restricted to an oxythermal habitat band suitable for cold-water fishes and filtered to include target strengths consistent with age-2 + cisco and lake trout, while ROV footage provided species-level confirmation and informed apportionment of acoustic targets. Cold-water fishes were confined to the metalimnion and occurred at low but measurable densities. Based on combined acoustic and visual information, mean age-2 + cisco abundance was estimated at N = 815. Biomass estimates were similar to estimates from other self-sustaining inland lake populations. The presence of multiple year classes and older fish indicated high survival and ongoing recruitment. These results provided the first quantitative estimates of the only known population of Lake Erie “albus” cisco and suggests that Crystal Lake supports a viable source population for restoration efforts.

Pennsylvania↗
USGS2026

Volcanic ash in the airways: Compositional controls on inflammation, immune modulation, and infection risk

Introduction More than one billion people live within 100 km of an active volcano, yet the respiratory hazard of ash resists generalization. Bulk composition modulates eruption parameters, therefore respirability, and determines the availability of crystalline silica and labile metals in basaltic ash. Areas covered We review the health-pertinent properties of volcanic ash, consistently reported symptoms of acute exposure, and the thin, confounded evidence for chronic disease, where co-exposure to volcanic gases and aerosols impairs attribution. We develop an underexplored possibility: volcanic environments increase the risk of environmentally acquired lung infection via ash fomites carrying viable bacteria, innate defense impairment, including iron-dependent nutritional immunity, and selection for pathogen metal-resistance systems in metal-rich volcanic environments. Nontuberculous mycobacterial lung disease in Hawai‘i and an exploratory country-level comparison of epidemiology metrics with volcanism test whether the disease axis is visible in existing data. Expert opinion Volcanic ash hazards are eruption-specific and crystalline silica and labile metals are joined by a scarcely tested third. That is, environmentally acquired bacterial lung infections are higher in ‘volcanic’ countries and account for a greater share of respiratory infections; both outcomes are ecological and hypothesis-generating. The infectious disease pathway and health effects of chronic exposure remain the least constrained assessment element.

Expert Review of Respiratory Medicine↗
USGS2026

Laboratory-based assessment of quantitative PCR to describe Arctic fish assemblages in surface water affected by acid rock drainage

Permafrost thaw has been identified as a cause of metal mobilization from acid rock drainage and transport to Arctic rivers. Elevated metal concentrations and precipitation of Fe(III) minerals (i.e., rusting) in surface waters deteriorates water quality and raises questions about ecosystem effects, especially to the health of fish species. Environmental DNA (eDNA) analyses could be used for assessing impacts of acid rock drainage to fish assemblages but may be prone to biases like polymerase chain reaction (PCR) inhibition. This study tested whether water from Arctic rivers affected by acid rock drainage influenced the efficacy of quantitative PCR (qPCR) for detecting fish. Water samples from rivers influenced by acid rock drainage were collected, characterized, and sterilized. Fish tissue was then added and mixed, and aliquots were analyzed using qPCR to assess species-specific detection sensitivity, specificity, and inhibition. In experiments, qPCR exhibited perfect species-specific assay sensitivity. There was little evidence for qPCR inhibition, whereas amplification efficiency was higher in approximately half of the samples. In mixed species assemblages, the proportion of species-specific target genes detected was significantly correlated to the proportion of tissue present for most targets. Results indicate that qPCR-based approaches, such as those often used in eDNA analyses, may help describe Arctic fish species assemblages within surface waters affected by acid rock drainage. Evaluation of qPCR methods described in this laboratory-based study using field-collected samples could help determine the effectiveness of these approaches in natural systems.

Alaska↗
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