Search

The Susquehanna River basin is one of the largest and most diverse watersheds in the northeastern United States, however, its historically renowned Micropterus dolomieu (smallmouth bass–SMB) fishery has been in decline since the mid-2000s. Agricultural herbicide runoff has been identified as a major risk for Susquehanna basin SMB populations given their effects as endocrine disrupting compounds (EDCs). During the summers of 2016 and 2017, we assessed potential threats to SMB populations in 11 tributaries to the Juniata River, the second largest tributary to the Susquehanna River. Passive water samplers were installed for 38–39 days in ecologically important tributaries to quantify six common herbicides, and SMB were collected from nine sites in 2016 and 2017 to assess their health and morphology. Our passive water samplers showed markedly higher EDC concentrations than has previously been documented in the Juniata basin, with atrazine occurring at all sites and in the highest concentrations (11.09–91.02 ng/L). SMB blood samples revealed complete prevalence (100%) of vitellogenin, an egg protein precursor, in male fishes further confirming previous rates male vitellogenisis. Additionally, SMB hepatosomatic index (HSI) was statistically higher in female SMB than in male SMB (P

Horizontal drilling and hydraulic fracturing extraction procedures have become increasingly present in Pennsylvania where the Marcellus Shale play is largely located. The potential for long-term environmental impacts to nearby headwater stream ecosystems and aquatic bacterial assemblages is still incompletely understood. Here, we perform high-throughput sequencing of the 16 S rRNA gene to characterize the bacterial community structure of water, sediment, and other environmental samples (n = 189) from 31 headwater stream sites exhibiting different histories of fracking activity in northwestern Pennsylvania over five years (2012–2016). Stream pH was identified as a main driver of bacterial changes within the streams and fracking activity acted as an environmental selector for certain members at lower taxonomic levels within stream sediment. Methanotrophic and methanogenic bacteria (i.e. Methylocystaceae, Beijerinckiaceae, and Methanobacterium) were significantly enriched in sites exhibiting Marcellus shale activity (MSA+) compared to MSA− streams. This study highlighted potential sentinel taxa associated with nascent Marcellus shale activity and some of these taxa remained as stable biomarkers across this five-year study. Identifying the presence and functionality of specific microbial consortia within fracking-impacted streams will provide a clearer understanding of the natural microbial community’s response to fracking and inform in situ remediation strategies.

Northern Map Turtles, Graptemys geographica, are a long-lived riverine species of conservation concern. We examined carapace morphology of Northern Map Turtles at Mount Union, a major turtle nesting area and former industrial site along the Juniata River in central Pennsylvania, USA. Among 535 reproductive adult female G. geographica, 29% exhibited abnormal shell shape, often in the form of an indentation in one or both sides of the carapace. Older females had a higher incidence of abnormalities than younger females. We quantified variation in shell shape, compared morphology among life history stages, and assessed thermal incubation environments of embryos to determine the magnitude and potential source of shell shape abnormalities. Geometric morphometric analysis showed significant differences among several carapace shape categories of adult turtles. No shell shape abnormalities were observed among 703 hatchlings collected from nests, and no shell shape abnormalities were observed among seven o...

Informed conservation of stream fishes requires detailed understanding of the effects of both natural processes and anthropogenic activities on genetic diversity. Brook Trout Salvelinus fontinalis, a salmonid native to eastern North America, typically resides in cold, high-quality stream ecosystems. The species has not only faced historical anthropogenic pressures, but also confronts current and future pressures. In a genetic analysis we used a reduced representation sequencing method (ddRADseq) to characterize 63 individuals from 23 streams where Brook Trout are native in the Appalachian region of Pennsylvania. A total of 2,590 loci passed filtering criteria, and 53% displayed significant association with a major stream drainage basin (Susquehanna or Allegheny; mean FST = 0.085). Mapping of the sequencing reads to the Atlantic Salmon Salmo salar genome revealed no clustering of high interdrainage FST values to specific genome regions. Evidence for genetic heterogeneity within each drainage basin ...

The environmental impacts of hydraulic fracturing, particularly those of surface spills in aquatic ecosystems, are not fully understood. The goals of this study were to (1) understand the effect of previous exposure to hydraulic fracturing fluids on aquatic microbial community structure and (2) examine the impacts exposure has on biodegradation potential of the biocide glutaraldehyde. Microcosms were constructed from hydraulic fracturing-impacted and nonhydraulic fracturing-impacted streamwater within the Marcellus shale region in Pennsylvania. Microcosms were amended with glutaraldehyde and incubated aerobically for 56 days. Microbial community adaptation to glutaraldehyde was monitored using 16S rRNA gene amplicon sequencing and quantification by qPCR. Abiotic and biotic glutaraldehyde degradation was measured using ultra-performance liquid chromatography--high resolution mass spectrometry and total organic carbon. It was found that nonhydraulic fracturing-impacted microcosms biodegraded glutaraldehyde faster than the hydraulic fracturing-impacted microcosms, showing a decrease in degradation potential after exposure to hydraulic fracturing activity. Hydraulic fracturing-impacted microcosms showed higher richness after glutaraldehyde exposure compared to unimpacted streams, indicating an increased tolerance to glutaraldehyde in hydraulic fracturing impacted streams. Beta diversity and differential abundance analysis of sequence count data showed different bacterial enrichment for hydraulic fracturing-impacted and nonhydraulic fracturing-impacted microcosms after glutaraldehyde addition. These findings demonstrated a lasting effect on microbial community structure and glutaraldehyde degradation potential in streams impacted by hydraulic fracturing operations.

Hydraulic fracturing (fracking) poses significant threats to freshwater resources and stream ecosystems. Little research exists to quantify the ecological impact and in Pennsylvania alone over 10,000 wells have been permitted. This study aimed to determine if hydraulic fracturing is having any impacts on stream ecosystem health by measuring stream pH and temperature, macroinvertebrate index of biological integrity (IBI), and the gill morphology of individuals in the Hydropsychidae Diplectrona taxa. Six streams in northwestern Pennsylvania were selected as study sites (three with fracking occurring in their watershed and three without fracking). IBI scores were significantly higher at non-fracked sites and were also correlated with stream pH. Macroinvertebrate gill width did not vary between fracked and non-fracked sites but was correlated with percent hydric soils, suggesting that hydric soils may be a good long-term indicator of stream dissolved oxygen. While our results did not indicate differences in H...

Two populations of Chrosomus species were found in two central Pennsylvania streams during electrofishing surveys in July and August of 2011. Analysis of sequence data from the cytochrome b region of the mitochondrial DNA confirmed visual observations that these fish were most closely related to C. oreas; a minnow-fish commonly occurring in Virginia drainages, but never documented in Pennsylvania. Limited genetic analysis suggests that the origin of these fish is either the result of human relocation from genetically uncharacterized native groups of C. oreas, or persistent relict populations. The documentation of this new fish to Pennsylvania, and uncertainty regarding their origin, underscores the need to perform a thorough phylogeographic assessment of C. oreas.

The ability to manipulate dissolved oxygen (DO) in a laboratory setting has significant application to investigate a number of ecological and organismal behavior questions. The protocol described here provides a simple, reproducible, and controlled method to manipulate DO to study behavioral response in aquatic organisms resulting from hypoxic and anoxic conditions. While performing degasification of water with nitrogen is commonly used in laboratory settings, no explicit method for ecological (aquatic) application exists in the literature, and this protocol is the first to describe a protocol to degasify water to observe organismal response. This technique and protocol were developed for direct application for aquatic macroinvertebrates; however, small fish, amphibians, and other aquatic vertebrates could be easily substituted. It allows for easy manipulation of DO levels ranging from 2 mg/L to 11 mg/L with stability for up to a 5 min animal-observation period. Beyond a 5 min observation period water temperatures began to rise, and at 10 min DO levels became too unstable to maintain. The protocol is scalable to the study organism, reproducible, and reliable, allowing for rapid implementation into introductory teaching labs and high-level research applications. The expected results of this technique should relate dissolved oxygen changes to behavioral responses of organisms.

Geometric morphology can be influenced by several biotic and abiotic factors, including predator–prey interactions and habitat structure. We measured the external morphology of Micropterus salmoides (largemouth bass, LMB) from two states in north-eastern United States, to assess the potential divergence of body shape. LMB varied in overall body shape (canonical variate analysis, P

Mercury (Hg) is a persistent element in the environment that has the ability to bioaccumulate and biomagnify up the food chain with potentially harmful effects on ecosystems and human health. Twenty-four streams remotely located in forested watersheds in northwestern PA containing naturally reproducing Salvelinus fontinalis (brook trout), were targeted to gain a better understanding of how Marcellus shale natural gas exploration may be impacting water quality, aquatic biodiversity, and Hg bioaccumulation in aquatic ecosystems. During the summer of 2012, stream water, stream bed sediments, aquatic mosses, macroinvertebrates, crayfish, brook trout, and microbial samples were collected. All streams either had experienced hydraulic fracturing (fracked, n = 14) or not yet experienced hydraulic fracturing (non-fracked, n = 10) within their watersheds at the time of sampling. Analysis of watershed characteristics (GIS) for fracked vs non-fracked sites showed no significant differences (P0.05), justifying comparisons between groups. Results showed significantly higher dissolved total mercury (FTHg) in stream water (P = 0.007), lower pH (P = 0.033), and higher dissolved organic matter (P = 0.001) at fracked sites. Total mercury (THg) concentrations in crayfish (P = 0.01), macroinvertebrates (P = 0.089), and predatory macroinvertebrates (P = 0.039) were observed to be higher for fracked sites. A number of positive correlations between amount of well pads within a watershed and THg in crayfish (r = 0.76, P0.001), THg in predatory macroinvertebrates (r = 0.71, P0.001), and THg in brook trout (r = 0.52, P0.01) were observed. Stream-water microbial communities within the Deltaproteobacteria also shared a positive correlation with FTHg and to the number of well pads, while stream pH (r = -0.71, P0.001), fish biodiversity (r = -0.60, P = 0.02), and macroinvertebrate taxa richness (r = -0.60, P = 0.01) were negatively correlated with the number of well pads within a watershed. Further investigation is needed to better elucidate relationships and pathways of observed differences in stream water chemistry, biodiversity, and Hg bioaccumulation, however, initial findings suggest Marcellus shale natural gas exploration is having an effect on aquatic ecosystems.

Importance It is unknown whether coronary revascularization, when added to optimal medical therapy, improves prognosis in patients with stable ischemic heart disease (SIHD) at increased risk of cardiovascular events owing to moderate or severe ischemia. Objective To describe baseline characteristics of participants enrolled and randomized in the International Study of Comparative Health Effectiveness With Medical and Invasive Approaches (ISCHEMIA) trial and to evaluate whether qualification by stress imaging or nonimaging exercise tolerance test (ETT) influenced risk profiles. Design, Setting, and Participants The ISCHEMIA trial recruited patients with SIHD with moderate or severe ischemia on stress testing. Blinded coronary computed tomography angiography was performed in most participants and reviewed by a core laboratory to exclude left main stenosis of at least 50% or no obstructive coronary artery disease (CAD) (