Scioto River Research Articles

Effects of agriculture and urbanization on the geochemistry of the Scioto River, Ohio

Despite efforts to reduce nonpoint source contamination of water resources, agriculture and urbanization remain primary sources that impair surface water quality. The Scioto River in Ohio, USA has headwaters in land dominated by primarily row-crop agriculture, then flows through metropolitan Columbus, the 14th largest city in the U.S. The river serves as a major drinking water source for the city and is dammed to form two reservoirs. The Scioto River was sampled for major ions, nutrients, and select trace elements weekly to monthly at five locations along changing agricultural and urban land use. Dissolved concentrations of many analytes were highest at the most upstream agricultural location, decreased to downtown Columbus, and increased at the location furthest downstream in agricultural land. The same trend was observed in discharge-weighted yields. Because much of the study area is underlain by carbonate bedrock, correlations with Ca2+ were likely to indicate a primarily geogenic source of the solute. Elements with moderate to strong positive correlations with Ca2+ included SO42−, Ni2+, Rb+, Mo6+, and Ba2+. Inorganic N species, emanating primarily from an agricultural source, had negative relationships with Ca2+. Concentration-discharge relationships revealed chemostatic to weak dilution of analytes positively correlated with Ca2+, suggesting a geogenic source of these elements that was weakly diluted with increasing discharge. Cu2+ showed a positive concentration-discharge slope, suggesting an anthropogenic input, but a defined source was not identified. Dams on the Scioto River that form drinking water reservoirs dampened chemical correlations and concentration-discharge relationships. Both agricultural and urban sources influence the river's chemistry based on hydroclimatic conditions and land use. Higher frequency sampling of the Scioto River during high flows allowed for a more nuanced understanding of sources of solutes to the river compared to previous work. Continued water quality monitoring is imperative to maintain and protect water quality resources, especially as urban populations are predicted to grow significantly in the next century.

The δ18O and δ2H fingerprint of the Scioto River: A detailed look into seasonal and spatial variations in the context of Ohio rivers

The global expansion and increased intensity of the human footprint causes modification of natural freshwater systems, particularly in densely populated areas. This poses a challenge for society where the water systems that humans rely on for domestic, industrial, and agricultural water are also the most physically and chemically disturbed. There is an urgent need to study hydrologic processes in surface water systems that flow through human-altered landscapes to better manage freshwater resources. Stable water isotopes (δ18O and δ2H) can be used as natural tracers to study the hydrologic patterns of rivers as they flow through these agricultural and urban landscapes. In this work, we investigate the seasonal and spatial hydrologic patterns of the Scioto River in Ohio, USA by analyzing stable water isotopes. Samples were collected over the course of one year (2021) from five locations that transition from intense agriculture to the metropolitan area of Columbus, Ohio. Results show that the Scioto River isotopic composition reflects a dampened seasonal precipitation pattern, where δ18O and δ2H are enriched in summer and depleted in winter. Scioto River transect patterns show that there was greater variability in stable isotopic composition in the upstream, agricultural reaches of the river. As the river flowed through the metropolitan Columbus area two “river-like” reservoirs generated isotopic homogenization along the Scioto without inducing isotopic enrichment, which is commonly observed from evaporation in river-reservoir systems. The Scioto River was put in context with other major Ohio river systems, to show the variability across the state. Isotopic composition differences among and within river systems across the state were induced by a combination of different environmental factors, like precipitation and river baseflow contribution. They were further affected by humans through land use modification and the constructions of dams and reservoirs. Overall, this study underlines the influence that urbanization and intensive agriculture have on rivers. In the context of the current hydrologic changes induced by climate change, this work emphasizes the importance of studying urban river hydrology in the context of joint climatic and human influences.

Fish as sentinels of antimicrobial resistant bacteria, epidemic carbapenemase genes, and antibiotics in surface water.

Surface waters, especially those receiving wastewater flows, can disseminate antimicrobial resistant bacteria (ARB), antimicrobial resistance genes (ARG), and antibiotics. In the Scioto River of central Ohio, United States, we evaluated fishes as potential sentinels of ARB and antimicrobial contamination and investigated the influence of antimicrobial exposure on the fish intestinal resistome. Seventy-seven fish were collected from river reaches receiving inputs from two wastewater treatment plants that serve the greater Columbus Metropolitan Area. Fish were screened for the presence of cephalosporin-resistant (CeRO) and carbapenem-resistant (CRO) organisms, epidemic carbapenemase genes, and antibiotic drugs and metabolites using culture methods, droplet digital PCR, and ultra-high performance liquid chromatography tandem mass spectroscopy (UHPLC-MS/MS). Nearly 21% of fish harbored a CeRO in their resistome, with 19.4% exhibiting bacteria expressing an AmpC genotype encoded by blaCMY, and 7.7% with bacteria expressing an extended-spectrum β-lactamase phenotype encoded by blaCTX-M. blaKPC and blaNDM were present in 87.7% (57/65) and 80.4% (37/46) of the intestinal samples at an average abundance of 104 copies. Three antibiotics–lincomycin (19.5%), azithromycin (31.2%) and sulfamethoxazole (3.9%)–were found in hepatic samples at average concentrations between 25–31 ng/g. Fish harboring blaCTX-M and those exposed to azithromycin were at greater odds of being downstream of a wastewater treatment plant. Fish that bioconcentrated antibiotics in their liver were not at greater odds of harboring CeRO, CRO, or epidemic carbapenemase gene copies in their resistome. Our findings confirm that fishes can be effective bioindicators of surface waters contaminated with ARB, ARG, and antibiotics. Moreover, our findings highlight the varying importance of different mechanisms that facilitate establishment of ARB in aquatic ecosystems.

Comparison of environmental microbiomes in an antibiotic resistance-polluted urban river highlights periphyton and fish gut communities as reservoirs of concern

Natural waterways near urban areas are heavily impacted by anthropogenic activities, including their microbial communities. A contaminant of growing public health concern in rivers is antibiotic resistant genes (ARGs), which can spread between neighboring bacteria and increase the potential for transmission of AR bacteria to animals and humans. To identify the matrices of most concern for AR, we compared ARG burdens and microbial community structures between sample types from the Scioto River Watershed, Ohio, the United States, from 2017 to 2018. Five environmental matrices (water, sediment, periphyton, detritus, and fish gut) were collected from 26 river sites. Due to our focus on clinically relevant ARGs, three carbapenem resistance genes (blaKPC, blaNDM, and blaOXA-48) were quantified via DropletDigital™ PCR. At a subset of nine urbanized sites, we conducted16S rRNA gene sequencing and functional gene predictions. Carbapenem resistance genes were quantified from all matrices, with blaKPC being the most detected (88 % of samples), followed by blaNDM (64 %) and blaOXA-48 (23 %). Fish gut samples showed higher concentrations of blaKPC and blaNDM than any other matrix, indicating potential ARG bioaccumulation, and risk of broader dissemination through aquatic and nearshore food webs. Periphyton had higher concentrations of blaNDM than water, sediment, or detritus. Microbial community analysis identified differences by sample type in community diversity and structure. Sediment samples had the most diverse microbial communities, and detritus, the least. Spearman correlations did not reveal significant relationships between the concentrations of the monitored ARGs and microbial community diversity. However, several differentially abundant taxa and microbial functions were identified by sample type that is definitive of these matrices' roles in the river ecosystem and habitat type. In summary, the fish gut and periphyton are a concern as AR reservoirs due to their relatively high concentration of carbapenem resistance genes, diverse microbial communities, and natural functions that promote AR.

Using solid-phase microextraction during ultrasound reveals higher aqueous PAHs release from contaminated sediment

Ultrasound (US) releases polycyclic aromatic hydrocarbons (PAHs) from contaminated creosote sediments and degrades PAHs in aqueous solution. However, it is unclear how much PAHs release occurs during active US compared to after US is stopped. In this study, solid-phase microextraction (SPME) was used to determine aqueous PAH concentrations desorbed from Little Scioto River creosote contaminated sediment during exposure to 20 kHz ultrasound (US) at a power of 430 W L−1. First, SPME fiber-water partition coefficients,KSPME, were experimentally determined and shown to be comparable with previous studies. Next, PAH concentrations released into aqueous solution were determined by sequentially exposing fresh, conditioned SPME fibers in a reactor containing the contaminated sediment and DI for 10 min periods. Three consecutive 10 min periods each were measured during US and after US. Compared to mixing only, PAHs desorbed during ultrasound was significantly higher. In addition, for phenanthrene, anthracene, and fluoranthene, US showed significantly higher aqueous concentrations during US compared with after US. For these less soluble PAHs, desorption into the aqueous phase reaches and surpasses expected equilibrium aqueous concentrations. However, when US is ceased, PAHs appear to resorb onto sediment resulting in the lower concentrations measured in these PAH compounds after US that are similar to expected equilibrium aqueous concentrations. Typical analytical extraction methods for determining the effects of US require stopping treatment and may underestimate the potential US has for release of contaminants from sediment during US. Using SPME during US treatment reveals that the concentration of PAHs during US may surpass the expected equilibrium aqueous concentration of some PAHs congeners. To our knowledge, this higher concentration observed during US compared to after US has not been shown previously.

Multiphase Rapid Filling Conditions of Tunnel System in Columbus, Ohio

The City of Columbus, Ohio is implementing a tunnel system to reduce the number of episodes of combined sewer overflows into the Scioto River. The tunnel systems provide relief to the existing Olentangy Scioto Interceptor Sewer. Two new tunnels being implemented are the OSIS Augmentation and Relief Sewer (OARS), in service since July 2017, and the Lower Olentangy Tunnel (LOT) that is planned to be in service in 2025. The performance of these tunnels in respect to high inflow conditions was investigated with the use of the HAST mixed flow model and the OpenFOAM CFD model to determine the magnitude of surges, the possibility of air pocket entrapment, air–water surging, and the consequences of uncontrolled air pocket releases through shafts. Inflows into the systems were obtained from a calibrated collection system SWMM model. Modeling results quantified surging in the tunnel dropshafts and their mitigation from built-in surge control chambers. HAST simulations also pointed to locations where air pockets could form. These results were used in OpenFOAM to determine the effects of uncontrolled air release through the shaft that links the two tunnels. It was shown that proper ventilation at the shaft will mitigate the growth of air phase pressure to damaging levels.

Variation in the Diet of Ducks During Spring Migration

ABSTRACTBecause management practices that promote the production of plant foods may differ from management practices that promote the production of aquatic invertebrates, a thorough understanding of the diet is needed to develop management strategies for various stages of the annual cycle for dabbling and diving ducks. Diet of dabbling (tribe Anatini) and diving (tribe Aythyini) ducks during breeding, autumn migration, and winter has been documented. Our goal was to estimate and compare the diet of blue‐winged teal (Spatula discors), gadwall (Mareca strepera), mallard (Anas platyrhyncos), lesser scaup (Aythya affinis), and ring‐necked duck (Aythya collaris) during spring migration in the Mississippi Flyway in the United States and evaluate variation among species. We collected 919 ducks for diet analysis from multiple wetlands at 6 sites across 4 states during the spring migration of 2006 and 2007. We collected ≥10 individuals of each species at each of the 6 study sites except we collected only 1 gadwall at the Scioto River site and 2 lesser scaup at the Cache River site. We detected that the proportion of plant and animal material in foods of each spring migrating duck species was in general intermediate of that found in wintering and breeding birds. Furthermore, the proportion of plant and animal material in the diet of species varied even among closely related species, indicating species are partitioning food sources along a protein‐carbohydrate gradient during spring migration. We recommend that resources for ducks be managed to provide diverse wetlands to support the varied diets of even closely related species. © 2021 The Wildlife Society.

First Records of Freckled Madtom (Noturus nocturnus) in Ohio, USA

Two new Ohio localities for the Freckled Madtom (Noturus nocturnus Jordan and Gilbert, 1886) were recently discovered. These are the first, and currently only, Freckled Madtom collected in Ohio waters. A single individual was collected in the Scioto River in Scioto County by the Midwest Biodiversity Institute (MBI) and a previously misidentified specimen was collected in the Ohio River at the Hannibal Locks and Dam by the Ohio River Valley Water Sanitation Commission (ORSANCO). The closest historical records are from the Little Sandy River and Big Sandy River drainages in eastern Kentucky. Other Ohio River collections have been made near the border of Kentucky and Indiana. The origins of the recent Ohio specimens are unknown; whether they emanate from other known populations or have been overlooked altogether is unclear.

On the monumentality of ditches

Archaeologists have increasingly broadened considerations of what is “monumental” and what relations with art, architecture, and landscapes constitute monumentality. This article documents the monumentality of ditches through an examination of 11 Scioto Hopewell ditches. Well known for their ornate crafts of exotic raw materials and massive geometric earthworks – constructed of ditches and embankments, usually in tandem – Scioto Hopewell was comprised of small-scale societies of the Middle Woodland period (1950–1550 BP) of the Scioto River Valley of southern Ohio. Though garnering archaeological attention for over two centuries, most research directed at understanding earthwork construction in this region has been relatively recent and primarily focused on embankment wall construction. This article represents the first exploration of Scioto Hopewell ditch construction and demonstrates that these ditches are monumental architecture that carry various meanings and whose construction was ritualized. Establishing a basis for the monumentality of Scioto Hopewell ditches has broad implications, as there is a global record of ditches that were multivalent and multi-functional landscape features that remain understudied beyond their possible functional or pragmatic purposes. This article demonstrates the value of the systematic archaeological examination of these features and the informational potential they hold.

Suspect screening of pharmaceuticals in fish livers based on QuEChERS extraction coupled with high resolution mass spectrometry

The presence of pharmaceuticals and personal care products (PPCPs) in aquatic environments is of increasing concern due to the presence of residues in fish and aquatic organisms, and emerging antibiotic resistance. Wastewater release is an important contributor to the presence of these compounds in aquatic ecosystems, where they may accumulate in food webs. The traditional environmental surveillance approach relies on the targeted analysis of specific compounds, but more suspect screening methods have been developed recently to allow for the identification of a variety of contaminants. In this study, a method based on QuEChERS extraction – using acetonitrile/water mixture as solvent and PSA/C18 for sample clean-up – was applied to identify pharmaceuticals and their metabolites in fish livers. Both target and suspect screening workflows were used and fish were sampled upstream and downstream of wastewater treatment plants from the Scioto River, Ohio (USA). The method performed well in terms of extraction of some target PPCPs, with recoveries generally above 90%, good repeatability (<20%), and linearity. Based on target analysis, lincomycin and sulfamethoxazole were two antibiotics identified in fish livers at average concentrations of 30.3 and 25.6 ng g−1 fresh weight, respectively. Using suspect screening, another antibiotic, azithromycin and an antidepressant metabolite, erythrohydrobupropion were identified (average concentrations: 27.8 and 13.8 ng g−1, respectively). The latter, reported, to the best of our knowledge, for the first time in fish livers, was also found at higher concentrations in fish livers sampled downstream vs. upstream. The higher frequency of detection for azithromycin in benthic feeding fish species (63%) as well as clusters identified between different foraging groups suggest that foraging behavior may be an important mechanism in the bioaccumulation of PPCPs. This study shows how suspect screening is effective in identifying new contaminants in fish livers, notably using differential analysis among different spatially distributed samples.

Leviathan in Chains: The Short-Lived Federalization of the Ohio Penitentiary

Leviathan in ChainsThe Short-Lived Federalization of the Ohio Penitentiary Sarah E. Paxton (bio) Erected along the Scioto River in the burgeoning Ohio capital, the Ohio Penitentiary was one of the earliest American prisons. Built to house predominantly men, the Ohio prison hosted thieves, bar brawlers, murderers, and—from July 1863 to March 1864—Confederate prisoners of war (POWs). Captain John Hunt Morgan and his infamous raiders spent the early months of 1863 wreaking havoc through southern Ohio, leaving ransacked businesses, upset railroads, smoldering canal boats, and a horde of livid Ohioans in their wake. Due in no small part to local outrage and Morgan’s infamy, upon their capture, Morgan and many of his raiders were locked away in the Ohio Penitentiary rather than the nearby Camp Chase POW camp. Four months later, in an embarrassing turn of events for both the state of Ohio and the Union Army, Morgan and his men broke out of the Ohio Penitentiary and escaped back to the Confederacy. A great deal of scholarship has been dedicated to John Hunt Morgan, contributing to his renown and status as a Southern folk hero. Yet historians have glossed over the four months he spent incarcerated. While Morgan’s escape may appear to have meant little in the grand scheme of the Civil War, it was a tumultuous time in the history of the Ohio Penitentiary and the evolving relationship between state and federal authorities. Housing POWs, particularly Confederate officers, was an uncommon occurrence with little to no precedent to guide the ill-defined relationship between the military and civilian guards. The presence of POWs in the civilian prison created financial, bureaucratic, and [End Page 67] political conflicts that neither the Ohio Penitentiary nor the Union Army were prepared to handle, leading to several crucial security measures falling through the cracks. Despite what the folk tales told of the rebel prisoners’ cunning, it was the buildup of tension between military and penitentiary staff and a lack of a clearly understood authority within the prison that allowed Morgan to escape. The trepidation with which the federal government approached commandeering the Ohio Penitentiary, and its failure to actuate their control, was demonstrative of the uncertainty surrounding the centralization of the American State. In July 1863, the Ohio Penitentiary took responsibility for the rebel prisoners begrudgingly. When Morgan and his men had been captured following the raids through Ohio and its neighbors, Union general Ambrose Burnside was concerned that the existing POW camps, like Camp Chase, would be unable to hold the raiders. Fearing they would escape, Burnside turned to the governor of Ohio and requested they keep the POWs in the penitentiary, where he was sure they would be more secure. Governor David Tod and Ohio Penitentiary warden Nathanial Merion acquiesced but initially restricted the number of POWs they would accept to 30. Despite this limit, the number housed at the Ohio Penitentiary quickly grew to 70.1 From the beginning, no one was happy with the arrangement. While the military provided some of the supplies for the care of the raiders, most of their needs were to be covered by state funds intended for the criminal convicts. The strain on the institution’s finances was exacerbated further by the fact that the penitentiary was not allowed to use the raiders as contract workers, a common practice with their criminal convicts.2 The federal POWs were therefore a drain on the already tight and heavily scrutinized finances of the state-run penitentiary. There was also the issue of space. The prison had an original maximum capacity of 500 inmates, though the institution was nearly always at or above capacity, perhaps a reason that Merion requested their charges be limited to 30. Prisoner comfort was evidently a nonissue for the prison administration, and, as a result, the penitentiary remained a diseased and brutal warehouse for years. The original wooden cells were perpetually damp and had tiny windows that allowed in little light or air.3 Physicians noted the consequences of [End Page 68] this environment on the physical health of the prisoners, first voicing concerns over the conditions in 1850. The warden agreed with their assessment in 1855...

Scioto Situations and the Steel Group Monument Assemblage

Abstract Scholars have offered various approaches to create a synthetic view of the Middle Woodland period that integrates geographically expansive and heterogenous material remains. Situation theory offers a synthetic analytical approach to the multiplicity of Middle Woodland ceremonialisms, allowing us to conceive of how people and communities across the midcontinent got caught up in shared conditions. Scioto situations—the Middle Woodland situations occurring within the central Scioto River valley of southern Ohio—have long been famous for their earthen monuments and ornate material symbols. This article analyzes Scioto situations through an examination of the monument assemblage of the Steel Group—an earthwork site with at least 13 earthen enclosures. In doing so, it offers an approach to monumentality that grounds interpretations of the aesthetic and physical nature of monuments within the complicated historical entanglements from which they emerged.

The Case of the Caldwell Mound: A Woodland Period Mound in the Central Scioto River Valley

This article presents a reconstruction and analysis of the Caldwell Mound located in the central Scioto River valley of southern Ohio. The mound contained a log tomb, at least four burials, and ass...

Analyses of organic residue from a conical pipe from the Niles-Wolford Mound (33Pi3), Pickaway County, Ohio

The Niles-Wolford Mound (33Pi3) was a conical Adena burial mound located along the Scioto River in Jackson Township, Pickaway County, Ohio. Excavations conducted in 1955 by the Ohio History Connection resulted in the discovery of a subfloor tomb with three burials. A tubular pipe found in association with one of the burials contained charred organic residue. Macrobotonical analysis of the material identified root or bark within the sample. Liquid chromatography-mass spectrometry (LC-MS) analyses detected the presence of various compounds, including an alkaloid. Radiocarbon dating places the mound to circa 2120 ± 30 BP. This research furthers our understanding of the timing, geographical extent, and ceremonial contexts of prehistoric plant tobacco use by the Adena culture and demonstrates the importance of museum collections for addressing such questions.

Reductions in fish-community contamination following lowhead dam removal linked more to shifts in food-web structure than sediment pollution

Recent increases in dam removals have prompted research on ecological and geomorphic river responses, yet contaminant dynamics following dam removals are poorly understood. We investigated changes in sediment concentrations and fish-community body burdens of mercury (Hg), selenium (Se), polychlorinated biphenyls (PCB), and chlorinated pesticides before and after two lowhead dam removals in the Scioto and Olentangy Rivers (Columbus, Ohio). These changes were then related to documented shifts in fish food-web structure. Seven study reaches were surveyed from 2011 to 2015, including controls, upstream and downstream of the previous dams, and upstream restored vs. unrestored. For most contaminants, fish-community body burdens declined following dam removal and converged across study reaches by the last year of the study in both rivers. Aldrin and dieldrin body burdens in the Olentangy River declined more rapidly in the upstream-restored vs. the upstream-unrestored reach, but were indistinguishable by year three post dam removal. No upstream-downstream differences were observed in body burdens in the Olentangy River, but aldrin and dieldrin body burdens were 138 and 148% higher, respectively, in downstream reaches than in upstream reaches of the Scioto River following dam removal. The strongest relationships between trophic position and body burdens were observed with PCBs and Se in the Scioto River, and with dieldrin in the Olentangy River. Food-chain length – a key measure of trophic structure – was only weakly related to aldrin body burdens, and unrelated to other contaminants. Overall, we demonstrate that lowhead dam removal may effectively reduce ecosystem contamination, largely via shifts in fish food-web dynamics versus sediment contaminant concentrations. This study presents some of the first findings documenting ecosystem contamination following dam removal and will be useful in informing future dam removals.

Associations between riverine landscape patches and internal and external environmental determinants are scale dependent: evidence from the Scioto River, USA

Associations between riverine landscape patches and internal and external environmental determinants are scale dependent: evidence from the Scioto River, USA

Quarrying History and Use of the Buena Vista Freestone, South-Central Ohio: Understanding the 19th Century Industrial Development of a Geological Resource

The Buena Vista Member of the Mississippian Cuyahoga Formation is an economically valuable freestone that is homogeneous with almost no sedimentary structures. The Buena Vista was one of the earliest clastic rocks quarried in Ohio. Early quarries dating at least back to 1814 were located in the hills on the north bank of the Ohio River near the village of Buena Vista, south-central Ohio. By the 1830s, quarries had also opened up along the route of the Ohio &amp; Erie Canal in the Portsmouth area to the east; followed by quarries that opened along a railway line that ran north up the Scioto River valley. Waterways transported the Buena Vista to many cities and towns, including Cincinnati, Ohio, Louisville, Kentucky, and Evansville, Indiana, on the Ohio River, New Orleans on the Mississippi River, and Dayton and Columbus on the Ohio canal system. Later railways transported this stone further afield to Illinois, Wisconsin, and Alberta. Census reports, industry magazines, and other historical accounts document the use of this stone across much of the eastern US and into Canada. Historically, it has been used for a variety of items, including entire buildings, canal structures, fence posts, and laundry tubs. Some 19th-century structures built with this stone remain in cities where it was once commonly used. Literature reviews, field observations, and lab analyses are here compiled as a useful reference to both the urban and field geologist in the identification of the Buena Vista Member, a historically important building stone, in buildings and outcrops, respectively.

Photodegradation of UV filters oxybenzone and sulisobenzone in wastewater effluent and by dissolved organic matter

Organic UV-filters are key ingredients found in sunscreens, cosmetics and plastic goods. Concerns have been raised about potential ecological and human health effects of certain organic UV filters that are currently FDA approved for use in the United States. Here, we investigate the photochemical fate of two of these compounds, oxybenzone and sulisobenzone. Both oxybenzone and sulisobenzone have previously been detected in surface waters, seawater, and treated wastewater effluent. Direct photolysis is found to be unimportant for these compounds, however, enhanced photodegradation of oxybenzone and sulisobenzone was observed under simulated solar irradiation in solutions of International Humic Substance Society standards (Pony Lake fulvic acid and Suwannee River natural organic matter), filtered wastewater effluent (Southerly Wastewater Treatment Plant in Lockbourne, OH), and Scioto River water (Columbus, OH) at pH 7. Quenching experiments with isopropanol revealed that the main pathway for degradation appears to be reaction with the hydroxyl radical (OH). Observed degradation rates were 2–3 times slower than estimates calculated using literature reported second-order rate constants and measured hydroxyl radical steady-state concentrations for Suwannee River natural organic matter, Pony Lake fulvic acid and Scioto waters. The Southerly sample, however, exhibited nearly identical expected and observed rate constants, which we take to indicate the presence of unidentified reactive species that can react with oxybenzone and sulisobenzone. Values obtained in this work were used to calculate second-order rate constants for oxybenzone and sulisobenzone with the hydroxyl radical, as well as to estimate environmental half-lives for these compounds. Near surface 24-h averaged half-lives of 3.0 and 4.0 days were calculated for oxybenzone and sulisobenzone, respectively. When extrapolated to an environmentally representative water column, these same 24-h averaged half-lives increased to 2.4 and 3.5 years, respectively.

Anthropogenic and natural determinants of fish food-chain length in a midsize river system

AbstractFood-chain length (FCL) is a key factor underlying patterns of energy flow and trophic structure in food webs. Natural gradients in resource availability, ecosystem size, and disturbance are thought to govern FCL in rivers. However, anthropogenic influences on FCL, including landscape modification (e.g., land-cover change) and river regulation (e.g., dams), remain unresolved. From 2010 to 2013 we characterized fish food webs at 12 river reaches along an ∼185-km section of the 6th-order Scioto River system (Ohio, USA) to assess the effects of natural and anthropogenic factors and the potential influence of shifts in foodweb structure (e.g., diversity, top-predator body size, intermediate predator richness) on fish FCL. Stable isotope-derived estimates of FCL ranged from 3.66 to 4.35, which are comparable to global values of FCL in rivers. A model-selection approach returned a set of linear regression models that explained 38 to 74% of the variation in FCL. Local ecosystem size (i.e., channel width)...

The Distribution and Abundance of mussels (Bivalvia: Unionidae) in Lower Big Walnut Creek from Hoover Dam to its Mouth, in Franklin and Pickaway Counties, Ohio

Big Walnut Creek in central Ohio once supported a mussel fauna of 40 species, but no systematic study of the mussels of the creek has been done. The objective of the current study was to determine the distribution and abundance of mussels in Big Walnut Creek downstream of Hoover Dam (RM 36.7) to its mouth with the Scioto River. The extant (living and freshly dead shells) and total (extant plus weathered and subfossil shells) mussel communities were determined at 21 sites. Two techniques were used to determine the mussel community at each site: timed searches and transect/quadrat sampling. Shannon-Weiner (H’) values, Jaccard Coefficient of similarity values, and percent extant species were calculated for the mussel communities at each location. Student T-tests were used to determine where either a significant change in community structure occurred based on the metrics listed above. The mussel communities from Hoover Dam to Whitehall (RM 22.0) had maintained their diversity. The historic and extant communities in this reach were essentially the same (Jaccard Coefficient = 83% and percent extant species = 78%) with H’ values for this reach not significantly different when comparing the total and extant communities (t = 1.08, p &gt; 0.05). The communities from RM 22.0 to RM 15.0 (just downstream of Three Rivers MetroPark) had fewer extant species (Jaccard Coefficient and percent extant values of 62% and 36%, respectively), and significantly diminished species diversity (t = 2.35, p &lt; 0.05). Diminished species diversity continued to be expressed downstream (t = 2.48, p &lt; 0.05), with some recovery (Jaccard Coefficient = 67% and percent extant = 42%) as we approached the mouth of the creek. This improvement may be a result of movement of mussels (as larvae attached to fish hosts) from the Scioto River.