Ohio River Research Articles

Paddlefish movement and dam passage in the Ohio and Kanawha Rivers, West Virginia

The Paddlefish (Polyodon spathula), a large-bodied and highly migratory species of large river systems, has experienced population declines or extirpation in parts of its native range. As an effort to reestablish a Paddlefish population in the Ohio River of West Virginia, the West Virginia Division of Natural Resources has stocked fingerling Paddlefish in the previous two decades. Post-stocking studies could assess the status of the reintroduced population, which includes collecting information on their seasonal movements and dam passage frequency through navigation dams of the Ohio and Kanawha Rivers. Using acoustic telemetry techniques, we monitored seasonal movements and assessed dam passage of five Paddlefish in the Robert C. Byrd Pool of the Ohio and Kanawha rivers. Paddlefish were highly mobile with two individuals using the entire R.C. Byrd Pool during the 11-month study period. Most movements occurred during the expected spawning period of April and May, where all individuals frequented the upper section of the pool in the Kanawha River. Downstream passage was documented for one individual at the R.C. Byrd lock during July 2023, but no evidence of upstream passage was documented for the locks at Racine (Ohio River) or Winfield (Kanawha River). Tagging of additional Paddlefish would be beneficial to increase sample size for future assessments and continue efforts toward the long-term conservation and management of Ohio River Paddlefish.

Population genetics of the freshwater red alga Batrachospermum gelatinosum (Rhodophyta) II: Phylogeographic analyses reveal spatial genetic structure among and within five major drainage basins in eastern North America.

The freshwater red alga Batrachospermum gelatinosum has a well-documented distribution spanning historically glaciated and unglaciated eastern North America. This alga has no known desiccation-resistant propagule; thus, long-distance dispersal events are likely rare. We predicted strong genetic structure among drainage basins and admixture among sites within basins. We predicted greater genetic diversity at lower latitude sites because they likely serve as refugia and the origin of northward, post-Pleistocene range expansion. We used 10 microsatellite loci to investigate genetic diversity from 311 gametophytes from 18 sites in five major drainage basins: South Atlantic Gulf, Mid-Atlantic, Ohio River, Great Lakes, and Northeast. Our data showed strong genetic partitioning among drainage basins and among sites within basins, yet no isolation by distance was detected. Genetic diversity varied widely among sites and was not strictly related to latitude as predicted. The results from B. gelatinosum provide strong support that each stream site contributes to the unique genetic variation within the species, potentially due to limited dispersal and the prevailing reproductive mode of intragametophytic selfing. Simulations of migration suggested post-Pleistocene dispersal from the Mid-Atlantic. Batrachospermum gelatinosum potentially persisted in refugia that were just south of the ice margins rather than in the southernmost part of its range. Research of other taxa with similar ranges could determine whether these results are generally applicable for freshwater red algae. Nevertheless, these results from B. gelatinosum add to the growing literature focused on the patterns and genetic consequences of post-Pleistocene range expansion by eastern North American biota.

Socioeconomic Factors Affect Access to Kidney Transplant in the Ohio River Valley

Socioeconomic Factors Affect Access to Kidney Transplant in the Ohio River Valley

Sensitivity analysis of a hydrodynamic and harmful algal model in a riverine system

Simulating algae blooms using a hydrodynamic-water quality model is challenging because it requires a thorough understanding of physical and biological processes and involves numerous parameters. This study conducted a sensitivity analysis of the EFDC+ hydrodynamic and water quality model for simulating cyanobacteria growth, an important Harmful Algal Bloom (HAB) species in the Ohio River, USA. The sensitivity analysis assessed 23 model input parameters, divided into nine functional groups according to their characteristics. This assessment analyzes the impact of changing these input parameters on four water quality model outputs including algae (i.e., cyanobacteria), dissolved oxygen, total nitrogen, and total phosphorus. Light extinction parameters, maximum algal growth rate, and algal base metabolism were identified as the most sensitive parameters for simulating algal growth. Solar radiation required for algal growth was moderately sensitive. Currently, there are only a few studies that simulate HAB dynamics in riverine systems. This study deepens our understanding of HAB development in rivers with lock and dam structures that create a series of pools along the river. Future work will involve focusing on the sensitive parameters in model calibration.

Assessment of toxicity potential of freely dissolved PAHs using passive sampler in Kentucky Lake and Ohio River

Polycyclic aromatic hydrocarbons (PAHs) are characterized with high KOW values, which lead to their recalcitrant nature, bioaccumulation, and biotoxicity, adversely affects the environment. Passive samplers (PS) have proven effective in measuring bioavailable PAH concentrations for toxicity assessments. In this study, we used low-density polyethylene (LDPE) to measure freely dissolved PAH concentrations (Cfree) in Kentucky Lake (KL) and Ohio River (OH), USA. PAHs toxicity potential in sediment was assessed using equilibrium partitioning sediment benchmarks toxic units (ESBTUs) and the interstitial water toxic units (IWTUs) that were derived from OC-normalized concentration (COC) and Cfree, respectively. The Cfree in April and June were 127 and 97 times higher in OH than in KL, respectively. Moreover, ESBTUs were higher in both the KL and OH compared to the IWTUs, suggesting that ESBTUs overestimate the toxicity potential to organisms. These results indicate that PS provides a reliable method for assessing the toxicity potential in sediments.

A snowfall climatology of the Ohio River Valley, USA

Snowfall in the Ohio River Valley, USA, presents a relatively unique challenge due to the large gradient of event frequency and magnitude, and subsequent levels of preparation within local communities. Even relatively small magnitude events can cause widespread impacts due to available infrastructure. Here we present a climatology of snowfall conditions and events over a 74-year period using a network of daily observational stations across the region. Snowfall totals and event frequencies both exhibit a southwest to northeast gradient of increasing snowfall, where the majority of snowfall (> 80%) occurs during the core winter months of December through February. There is a clear influence of Lake Erie on snowfall conditions in the northeast corner of the domain, where snowfall frequency, totals, and trends are substantially higher within the lake belt relative to areas further inland. Over time, snowfall significantly increased downwind of Lake Erie by as much as 42%, while significant decreases of over 55% occurred in central Tennessee and eastern Ohio. Intra-seasonally, snowfall totals trended significantly less during November and March for much of the domain, suggesting a compression of the snowfall season to more core winter months. Trends in snowfall frequency were apparent for many sub-regions, however evidence here suggests the trends in snowfall totals were primarily driven by trends in snowfall magnitude per event.

Comments: Pore Space Leasing: Insights From a Bakken Surface Owner’s Perspective

During a trip to western North Dakota last month to visit my family, I met with a long-time friend, Dick, who holds subsurface mineral rights and surface rights in the Bakken area. Over coffee, German sausage, and kuchen, our conversation naturally turned to the leasing of pore space. Dick has lately been approached by landmen with what they describe as “great deals” for purchasing the underlying pore space associated with his surface rights. They hesitate to provide specific offers. Instead, he described the initial interactions as “like making a deal for a new car or tractor.” The landmen reply, “I’ll need to go back to the client [my boss or manager] with your questions.” Sound familiar? Like most US states, pore space ownership correlates with surface ownership in North Dakota. In August 2022, the North Dakota Supreme Court clarified the rights of surface owners and the need for compensation for pore space use. It also created uncertainty for oil and gas operators who previously had more latitude in using pore space without compensation. Dick knows his way around the dealmaking involved in oil and gas rights leasing, having been involved in many landmen inquiries in the days of the Bakken boom and subsequent wheeling and dealing. However, pore space leasing is relatively nascent and faces similar unknowns like the early days of Bakken pitches. During his research, he came up against the same walls I have over the years while writing about pore space leasing for carbon sequestration. Becoming more apparent as deals gain momentum is the lack of specifics for comparable deals. As when purchasing a home, identifying “comps” for similar properties is a necessary part of the process. But the amounts paid for pore space are closely held, generally not publicly available. It’s impossible to determine if a deal is good or bad. Is the compensation fair? And individual surface owners and landowners rights associations (and/or their attorneys) are aware of the 45Q tax credit of $85/tonne of CO2 captured and stored available to the project developer/operator under the 2022 US Inflation Reduction Act. How should this be factored into the determination of fair compensation? For example, the Ohio River Valley Institute (ORVI), a think tank focused on the Appalachian region, in March described a proposal by Tenaska Inc. to lease underground pore space across seven counties (approximately 80,000 acres) in Ohio, Pennsylvania, and West Virginia for the sequestering of 150 million tons of CO2. In a document proposing terms for the acquisition of nearly 1,400 acres of pore space in county parklands in Washington County, Pennsylvania, Tenaska offered about $4 million for the county’s 2.6-million-metric-ton share of the CO2 between 2027 and 2056, or about $1.50 per metric ton. The ORVI called the deal “ridiculous and borderline insulting.” It supports this declaration by highlighting a comp available from August 2023. Mountaineer GigaSystem LLC offered the state of West Virginia a royalty of $3.35 per metric ton to sequester CO2 on public land in Mason County—more than two times what Tenaska is offering Washington County. It also made the point that the ultimate cost of capturing and sequestering the CO2 will not be borne by Tenaska or its customers. The 45Q tax credit will provide Tenaska $423 million annually for sequestering 5 million tons of CO2 annually. The region’s lease revenue will be $7.5 million. To align with the available comp, ORVI said Tenaska’s offer should at least match Mountaineer’s $3.35 instead of the proposed $1.50 per metric ton. In the western US, ExxonMobil is seeking to pay the US Bureau of Land Management (BLM) to inject 150 million tons of CO2 over the course of 20 years into 100,000 subsurface acres of pore space on federal lands. The proposed Snowy River CO2 project in Carter County, Montana, is still in the environmental assessment and public comment phase, and the BLM’s compensation for the use of the land is not yet publicly disclosed or finalized. Our takeaway after finishing the sausage and kuchen? As pore space leasing evolves, landowners like Dick face a complex landscape of uncertain deals and opaque compensation. With legal clarifications and potential tax credits in play, navigating these new frontiers requires keen insight and vigilance to ensure fair and beneficial agreements for all involved.

Ohio River basin snow ablation and the role of rain‐on‐snow

AbstractSnow cover ablation within the Ohio River Basin (ORB) plays an important role in regional hydroclimatology, while also representing a potential hazard during large and rapid events. Rain‐on‐snow ablation is a particular challenge, where runoff rates are typically enhanced due to the dual inputs of snowmelt and liquid precipitation. Here, we present a 40‐year climatology of snow ablation events frequency, intensity, and timing for the ORB using a 4‐km gridded snow‐water‐equivalent dataset, focusing on the relative proportion of events caused by rain‐on‐snow and changes over time. Spatial patterns of snow ablation frequency and intensity mirror that of seasonal snowfall totals, with higher (lower) values in the northern and eastern (southern) portions of the basin. Rain‐on‐snow events represent approximately 40% of all ablation events within the basin and result in approximately 24%–25% more snow‐water‐equivalent loss than non‐rain‐on‐snow events, plus an additional 3–12 mm of liquid precipitation per event on average. Peak frequency of ablation and rain‐on‐snow events occurs in late winter and early spring, similar to that of the surrounding region. Over time, the frequency of ablation and rain‐on‐snow events has decreased in the northern and eastern portions of the basin, in some cases by as much as 30%. Trends in event magnitudes were more isolated but decreased across portions of central IN, northern KY, eastern OH and northern WV. Additionally, the magnitude of precipitation during rain‐on‐snow events has increased across the region, extending from northern KY into western PA by over 100% in many cases. Broadly, we find tendencies towards fewer events with less snow loss but more liquid precipitation that suggest complicated impacts to the hydroclimatology warranting further investigation.

First report of freshwater sponges (Porifera: Demospongiae: Spongillida: Spongillidae) in western Pennsylvania (Ohio River Watershed)

First report of freshwater sponges (Porifera: Demospongiae: Spongillida: Spongillidae) in western Pennsylvania (Ohio River Watershed)

Distribution of invasive scud, Apocorophium lacustre (Vanhoffen, 1911) in the Illinois Waterway, USA: Do habitat and water quality variables influence spatial distribution and relative abundance?

Apocorophium lacustre – a species of benthic amphipod native to American and European estuaries along the North Atlantic Ocean – has rapidly expanded outside of its native range and is now established in the Illinois, Upper Mississippi, and Ohio river systems, USA. A. lacustre is considered high risk for colonization and disruption of the Laurentian Great Lakes’ benthic communities. To further our understanding of factors influencing A. lacustre distribution and its threat to the Great Lakes, zoobenthic and habitat data were collected from colonization samplers (i.e., rock bags) deployed at 370 sites along the Illinois Waterway. A. lacustre was found in the lower six pools of the Illinois Waterway and was the most abundant amphipod collected in those pools. Our results parallel other studies in that A. lacustre was not observed upstream of Dresden Island Pool, but A. lacustre was found ~11 km farther upstream of any previous records. Generalized linear mixed effects modeling indicated that parameters pertaining to food availability, water quality, and impoundment influenced A. lacustre abundance. Model averaging identified five statistically significant variables: A. lacustre abundance was negatively associated with turbidity, fluorescent dissolved organic matter, and vegetation density and positively associated with temperature and downstream distance (i.e., closer to the next downstream dam). Our findings of what factors influence A. lacustre abundance should be of broad interest to risk assessment and invasion forecasting in other regions where A. lacustre have been or may be introduced.

A Stochastic Statistical Model for U.S. Outbreak-Level Tornado Occurrence Based on the Large-Scale Environment

Abstract Tornado outbreaks—when multiple tornadoes occur within a short period of time—are rare yet impactful events. Here we developed a two-part stochastic tornado outbreak index for the contiguous United States (CONUS). The first component produces a probability map for outbreak tornado occurrence based on spatially resolved values of convective precipitation, storm relative helicity (SRH), and convective available potential energy. The second part of the index provides a probability distribution for the total number of tornadoes given the outbreak tornado probability map. Together these two components allow stochastic simulation of location and number of tornadoes that is consistent with environmental conditions. Storm report data from the Storm Prediction Center for the 1979–2021 period are used to train the model and evaluate its performance. In the first component, the probability of an outbreak-level tornado is most sensitive to SRH changes. In the second component, the total number of CONUS tornadoes depends on the sum and gridpoint maximum of the probability map. Overall, the tornado outbreak index represents the climatology, seasonal cycle, and interannual variability of tornado outbreak activity well, particularly over regions and seasons when tornado outbreaks occur most often. We found that El Niño–Southern Oscillation (ENSO) modulates the tornado outbreak index such that La Niña is associated with enhanced U.S. tornado outbreak activity over the Ohio River Valley and Tennessee River Valley regions during January–March, similar to the behavior seen in storm report data. We also found an upward trend in U.S. tornado outbreak activity during winter and spring for the 1979–2021 period using both observations and the index. Significance Statement Tornado outbreaks are when multiple tornadoes happen in a short time span. Because of the rare, sporadic nature of tornadoes, it can be challenging to use observational tornado reports directly to assess how climate affects tornado and tornado outbreak activity. Here, we developed a statistical model that produces a U.S. map of the likelihood that an outbreak-level tornado would occur based on environmental conditions. In addition, using that likelihood map, the model predicts a range of how many tornadoes could occur in these events. We found that “storm relative helicity” (a proxy for potential rotation in a storm’s updraft) is especially important for predicting outbreak tornado likelihood, and the sum and maximum value of the likelihood map is important for predicting total numbers for an event. Overall, this model can represent the typical behavior and fluctuations in tornado outbreak activity well. Both the tornado outbreak model and observations agree that the state of sea surface temperature in the tropical Pacific (El Niño–Southern Oscillation) is linked to tornado outbreak activity over the Ohio River Valley and Tennessee River Valley in winter through early spring and that there are upward trends in tornado outbreak activity.

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.

Assessment of Movement and Dam Passage of Paddlefish in the Ohio River, West Virginia.

Paddlefish (Polydon spathula), a large-bodied and highly migratory species of large river systems, has experienced population declines or extirpation in parts of its range. As an effort to reestablish Paddlefish populations in the Ohio River of West Virginia, the West Virginia Division of Natural Resources has periodically stocked Paddlefish, but post-stocking studies are needed to assess the status of the reintroduced population, including information on movements of Paddlefish or on their passage through navigation dams of the Ohio River. Using telemetry techniques, we monitored seasonal movements and assessed dam passage of five Paddlefish in the Robert C. Byrd pool of the Ohio and Kanawha rivers. Paddlefish were highly mobile with two individuals using the entire R.C. Byrd pool during the 11-month study period. The highest movement rates occurring during the expected spawning period of April and May, where all individuals frequented the upper section of the pool in Kanawha River. Downstream passage was documented for one individual at the R.C. Byrd lock during July 2023, but no evidence of passage was documented for the locks at Racine or Winfield. Tagging of additional Paddlefish is planned, which will increase sample size for future assessments and continue efforts toward the long-term conservation and management of Ohio River Paddlefish.

A data-driven global flood forecasting system for medium to large rivers.

Losses from catastrophic floods are driving intense efforts to increase preparedness and improve response to disastrous flood events by providing early warnings. Yet accurate flood forecasting remains a challenge due to uncertainty in modeling, calibrating, and validating a useful early warning system. This paper presents the Requisitely Simple (ReqSim) flood forecasting system that includes key variables and processes of basin hydrology and atmospheric forcing in a data-driven modeling framework. The simplicity of the modeling structure and data requirements of the system allows for customization and implementation in any medium to large rain-fed river basin globally, provided there are water level or discharge measurements at the forecast locations. The proposed system's efficacy is demonstrated in this paper through providing useful forecasts for various river basins around the world. This include 3-10-day forecasts for the Ganges and Brahmaputra rivers in South Asia, 2-3-day forecast for the Amur and Yangtze rivers in East Asia, 5-10-day forecasts for the Niger, Congo and Zambezi rivers in West and Central Africa, 6-8-day forecasts for the Danube River in Europe, 2-5-day forecasts for the Parana River in South America, and 2-7-day forecasts for the Mississippi, Missouri, Ohio, and Arkansas rivers in the USA. The study also quantifies the effect of basin size, topography, hydrometeorology, and river flow controls on forecast accuracy and lead times. Results indicate that ReqSim's forecasts perform better in river systems with moderate slopes, high flow persistence, and less flow controls. The simple structure, minimal data requirements, ease of operation, and useful operational accuracy make ReqSim an attractive option for effective real-time flood forecasting in medium and large river basins worldwide.

Characterizing variation in late precontact diets using dental microwear texture analysis: a Caborn-Welborn example

ABSTRACT The Caborn-Welborn phase identifies late precontact and early postcontact (ca. AD 1400–1700) peoples of the lower Ohio River valley in Indiana, Kentucky, and Illinois who coalesced following the collapse of the Angel chiefdom. Our current understanding of Caborn-Welborn foodways is that they, like their contemporaries in other parts of eastern North America, subsisted largely on maize and wild game, supplemented by a wide range of other wild and cultivated foods. While technically accurate, this generic picture of late precontact diets does not do justice to the many microclimatological and cultural nuances that characterized local native southeastern and midwestern diets. Dental microwear texture analysis (DMTA) is a method to understand diet by analyzing the microscopic scratches and pits left on teeth during mastication. Combining DMTA with other lines of evidence, we confirm previous studies that indicate that at least some Caborn-Welborn peoples consumed less maize than their ancestors living at the Angel site. Rather than understanding Caborn-Welborn peoples as practicing a generic late precontact subsistence strategy, our study highlights how Caborn-Welborn peoples chose to eat less maize and consume more hard wild foods such as nuts compared with their contemporaries.

The Falls of the Ohio River: America's First Fossil Bed

Abstract The Falls of the Ohio is a world-renowned geoheritage site of palaeontological and geological importance that also played key roles in the cultural and historical development of America. Studied by geologists for over two centuries, over 600 species of fossils are known from the site, hundreds of which were first described here. Beyond geology, the Falls of the Ohio can also be considered the origin and ending of the Lewis and Clark expedition, as well as an important location for naturalists and educators. A treasure of natural and human history and a National Natural Landmark, this spectacular 220 acre (89 ha) expanse of fossiliferous bedrock is worthy of ongoing study and protection.

Tracing histoplasmosis genomic epidemiology and species occurrence across the USA

ABSTRACT Histoplasmosis is an endemic mycosis in North America frequently reported along the Ohio and Mississippi River Valleys, although autochthonous cases occur in non-endemic areas. In the United States, the disease is provoked by two genetically distinct clades of Histoplasma capsulatum sensu lato, Histoplasma mississippiense (Nam1) and H. ohiense (Nam2). To bridge the molecular epidemiological gap, we genotyped 93 Histoplasma isolates (62 novel genomes) including clinical, environmental, and veterinarian samples from a broader geographical range by whole-genome sequencing, followed by evolutionary and species niche modelling analyses. We show that histoplasmosis is caused by two major lineages, H. ohiense and H. mississippiense; with sporadic cases caused by H. suramericanum in California and Texas. While H. ohiense is prevalent in eastern states, H. mississipiense was found to be prevalent in the central and western portions of the United States, but also geographically overlapping in some areas suggesting that these species might co-occur. Species Niche Modelling revealed that H. ohiense thrives in places with warmer and drier conditions, while H. mississippiense is endemic to areas with cooler temperatures and more precipitation. In addition, we predicted multiple areas of secondary contact zones where the two species co-occur, potentially facilitating gene exchange and hybridization. This study provides the most comprehensive understanding of the genomic epidemiology of histoplasmosis in the USA and lays a blueprint for the study of invasive fungal diseases.

Concentrations of 45 Per- and Polyfluoroalkyl Substances in North American River Otters (Lontra canadensis) from West Virginia, USA.

North American river otters (Lontra canadensis) are top predators in riverine ecosystems and are vulnerable to per- and polyfluoroalkyl substance (PFAS) exposure. Little is known about the magnitude of exposure and tissue distribution of PFAS in river otters. We measured 45 PFAS in various tissues of 42 river otters collected from several watersheds in the state of West Virginia, USA. The median concentrations of ∑All (sum concentration of 45 PFAS) varied among tissues in the following decreasing order: liver (931 ng/g wet weight) > bile > pancreas > lung > kidney > blood > brain > muscle. Perfluoroalkylsulfonates (PFSAs) were the predominant compounds accounting for 58-75% of the total concentrations, followed by perfluoroalkyl carboxylates (PFCAs; 21-35%). 8:2 fluorotelomer sulfonate (8:2 FTS), 10:2 FTS, and 6:2 chlorinated polyfluoroalkyl ether sulfonate were frequently found in the liver (50-90%) and bile (96-100%), whereas hexafluoropropylene oxide dimer acid (HFPO-DA) was rarely found. The hepatic concentrations of ∑All in river otters collected downstream of a fluoropolymer production facility located along the Ohio River were 2-fold higher than those in other watersheds. The median whole body burden of ∑All was calculated to be 1580 μg. PFOS and perfluorooctanoic acid (PFOA) concentrations in whole blood of some river otters exceeded the human toxicity reference values, which warrant further studies.

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.

The Hopewell Cosmic Airburst Event: A review of the empirical evidence

Abundance peaks in microscopic materials, including meltglass, microspherules, Ni, Ir, and Pt have been found in Native American Hopewell-age cultural strata. This discovery includes micrometeorites (possibly pallasites) recovered from heavily burned strata in two Hopewell villages. This evidence suggests that a prehistoric cosmic airburst/impact event occurred in the Ohio River valley. The peaks in these exotic materials only occur within a dark, charcoal-rich burn layer containing a wide range of Hopewell artifacts, and they are not found above or below the layer. Transgenerational oral histories and possibly two unique airburst-shaped Hopewell earthworks at or near the epicenter suggest that Native Americans living in the Ohio River valley may have been eyewitnesses to the impact event. AMS radiocarbon ages (n = 15) obtained directly from cultural and geological contexts indicate that the airburst/impact event occurred within a 70-year window from 1640-1570 cal BP. The Hopewell culture existed from ~2100-1500 cal BP and suffered a severe decline beginning ~1650 cal BP, suggesting that the proposed impact event occurred near the end of that span. After the proposed event, the hallmarks of the Hopewell culture, such as monumental landscape architecture, the largest geometric earthen enclosures in the world, intricate hilltop water management systems, massive burial mounds, and extensive ceremonial centers, were no longer constructed in the area impacted by the airburst. We propose that this cosmic airburst/impact event catalyzed the economic and sociopolitical decline and reorganization of the Hopewell cultural complex in the Ohio River valley for villages directly affected by the proposed airburst.