Ohio Sea Grant College Program

Phosphorus (P) is generally considered to be the main limiting nutrient to freshwater phytoplankton productivity. However, recent research is drawing attention to the importance of nitrogen (N) in freshwater eutrophication and N often constrains growth of cyanobacteria in small lakes. In this study we determined phytoplankton nutrient limitation in a large lake, Lake Erie during two growing seasons. During 2010 and 2011, nutrient enrichment bioassays (+P, +N and, +P and N) were conducted monthly from June through September with water collected in Maumee Bay (site MB18) and in the center of the western basin (site WBC). Nutrient concentrations were monitored every other week. At MB18, total P concentration was often >3 mmol/L and nitrate concentration decreased from >250 mmol/L in early summer to mmol/L in late summer. Nitrogen and P levels were about five-fold less at WBC. Bioassays indicated that phytoplankton nutrient limitation varied in summer, spatially, and even among phytoplankton groups. For site MB18, +P increased chlorophyll concentration in one of the eight bioassays, indicating that P did not typically limit production. For site WBC, +P increased chlorophyll concentration in six of the eight bioassays. As a result of very low ambient nitrate concentration (mmol/L) in late summer, +N (without P) increased chlorophyll concentration, suggesting symptoms of N-limitation. The N-fixing cyanobacterium Anabaena became dominant following N-limitation. This study highlights the need to reduce P loading to restore water quality. Furthermore, due to low nitrate concentration, the severity of the cyanobacterial blooms could be worse if not for N-limitation in western Lake Erie.

In response to degraded water quality, federal policy makers in the US and Canada called for a 40% reduction in phosphorus (P) loads to Lake Erie, and state and provincial policy makers in the Great Lakes region set a load‐reduction target for the year 2025. Here, we configured five separate SWAT ( US Department of Agriculture's Soil and Water Assessment Tool) models to assess load reduction strategies for the agriculturally dominated Maumee River watershed, the largest P source contributing to toxic algal blooms in Lake Erie. Although several potential pathways may achieve the target loads, our results show that any successful pathway will require large‐scale implementation of multiple practices. For example, one successful pathway involved targeting 50% of row cropland that has the highest P loss in the watershed with a combination of three practices: subsurface application of P fertilizers, planting cereal rye as a winter cover crop, and installing buffer strips. Achieving these levels of implementation will require local, state/provincial, and federal agencies to collaborate with the private sector to set shared implementation goals and to demand innovation and honest assessments of water quality‐related programs, policies, and partnerships.

To understand the role of cytokines during rotavirus infection, we assessed the kinetics of tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) (proinflammatory), IL-12 (Th1 inducer), gamma interferon (IFN-gamma) (Th1), IL-4 and IL-10 (Th2), and transforming growth factor beta (Th3) cytokine responses by enzyme-linked immunosorbent assay in serum and intestinal contents of neonatal gnotobiotic pigs and IL-12, IFN-gamma, IL-4, and IL-10 cytokine-secreting cell (CSC) responses of mononuclear cells from ileum, spleen, and blood by ELISPOT. Pigs received the virulent Wa P1A[8]G1 strain of human rotavirus (HRV) (VirHRV), attenuated Wa HRV (AttHRV), or mock (controls). The TNF-alpha levels peaked earlier and remained elevated in serum of the VirHRV group but peaked later in the AttHRV group. In serum, IL-6 was significantly elevated at postinoculation day (PID) 1 in the VirHRV group and at PID 3 in both HRV groups. The IL-12 was detected in serum of all pigs including controls with significantly elevated peaks in both HRV-infected groups, indicating a role for IL-12 in the induction of immune responses to rotavirus infection. Only low and transient IFN-gamma responses occurred in serum and intestinal contents of the AttHRV-infected pigs, compared to significantly higher and prolonged IFN-gamma responses in the VirHRV-infected pigs. This observation coincides with the diarrhea and viremia induced by VirHRV. The number of IFN-gamma-secreting cells was significantly higher in the ileum of the VirHRV group than in that of the controls. The number of IL-4 CSCs was significantly higher in ileum of both HRV groups than in that of the controls. Significantly higher levels of IL-10 in the serum occurred early in the VirHRV group, compared to lower levels in the AttHRV group. However, the number of IL-10 CSCs was significantly higher later in ileum and spleen of the AttHRV than in the VirHRV group, suggesting a delayed initiation of a Th2 response induced by AttHRV. A significantly higher percentage of pigs had IFN-gamma and IL-10 responses in serum after VirHRV infection than after AttHRV infection or in controls. These data indicate a balanced Th1/Th2 response during rotavirus infection, with higher cytokine levels early after infection with VirHRV compared to that with AttHRV. Mapping the kinetics and patterns of cytokine responses after rotavirus infection has important implications for induction of protective immunity by HRV vaccines. Higher protection rates may be associated with more balanced Th1- and Th2-type responses, but induction of higher earlier IFN-gamma (Th1) and proinflammatory cytokines triggered by VirHRV may also play an important role in the higher intestinal immunoglobulin A responses and protection rates induced by VirHRV.

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.

The author investigated the cognitive development of counseling students at 3 points in their training. A cross‐sectional analysis of 205 counseling master's students at 13 colleges and universities showed a linear trend between the students' progression through the program and their cognitive development. Initial results of a longitudinal study of students in 2 counseling programs corresponded with the results of the cross‐sectional data. The results of the cross‐sectional and initial longitudinal studies lend initial support to the idea that it may be possible to capture the broad development of counselor education students with a generalized model.

Cyanobacterial Harmful Algal Blooms (CyanoHABs) commonly increase water column pH to alkaline levels ≥9.2, and to as high as 11. This elevated pH has been suggested to confer a competitive advantage to cyanobacteria such as Microcystis aeruginosa . Yet, there is limited information regarding the restrictive effects bloom-induced pH levels may impose on this cyanobacterium’s competitors. Due to the pH-dependency of biosilicification processes, diatoms (which seasonally both precede and proceed Microcystis blooms in many fresh waters) may be unable to synthesize frustules at these pH levels. We assessed the effects of pH on the ecologically relevant diatom Fragilaria crotonensis in vitro , and on a Lake Erie diatom community in situ . In vitro assays revealed F. crotonensis monocultures exhibited lower growth rates and abundances when cultivated at a starting pH of 9.2 in comparison to pH 7.7. The suppressed growth trends in F. crotonensis were exacerbated when co-cultured with M. aeruginosa at pH conditions and cell densities that simulated a cyanobacteria bloom. Estimates demonstrated a significant decrease in silica (Si) deposition at alkaline pH in both in vitro F. crotonensis cultures and in situ Lake Erie diatom assemblages, after as little as 48 h of alkaline pH-exposure. These observations indicate elevated pH negatively affected growth rate and diatom silica deposition; in total providing a competitive disadvantage for diatoms. Our observations demonstrate pH likely plays a significant role in bloom succession, creating a potential to prolong summer Microcystis blooms and constrain diatom fall resurgence.

Abstract Hypoxia, defined as dissolved oxygen (DO) < 2 mg/L, in the central basin of Lake Erie has been studied since the mid‐1900s. Even so, spatial patterns of hypoxia, and episodic hypoxia in nearshore areas where drinking water plant intakes are located, are not well characterized owing to limited observations and short‐term dynamics. We evaluated a physically based, DO model with respect to patterns of hypoxia observed in Lake Erie. The DO model used assigned rates of sediment and water column oxygen demand that were temperature dependent but otherwise spatially and temporally uniform. The DO model was linked to National Oceanic and Atmospheric Administration's (NOAA) Lake Erie Operational Forecasting System hydrodynamic model, an application of the Finite Volume Community Ocean Model (FVCOM). Model temperature and DO were compared with observations from ship‐based studies, real‐time sensor networks and an array of moored sensors that we deployed in 2017. In years with dominant southwesterly winds, persistent downwelling occurred along the south shore, which resulted in a thinner thermocline and earlier initiation of hypoxia along the south shore than the north. Occasional northeast winds temporarily reversed this pattern, causing upwelling along the south shore that brought hypoxic water to nearshore locations and water intakes. The DO model reproduced observed spatial and temporal patterns of hypoxia and revealed locations subject to episodes of hypoxia, including nearshore Ohio, north of Pelee Island, and near the Bass Islands. Model skill was limited in some respects, highlighting the importance of accurate simulation of the thermal structure and spatial patterns of oxygen demand rates.

ABSTRACT The effects of added caseinate (CAS), casein hydrolyzate (CASHY) and whey protein hydrolyzate (WPHY) on acid, flavor and volatile compound production in a high protein and fiber soymilk yogurt‐like product were studied. High protein and fiber soymilk, produced by blending soaked, boiled and dehulled soybeans with Swiss cheese whey ultrafiltration permeate, was fermented with a mixed S. thermophilus and L. bulgaricus yogurt culture. The concentrations of lactic acid, key volatile compounds, i.e., acetaldehyde, acetone, and diacetyl, and the flavor and texture of the resulting soymilk based yogurt formulated with added CAS or CASHY were comparable to those in a milk yogurt control.

This essay argues that science education can gain from close engagement with the history of science both in the training of prospective vocational scientists and in educating the broader public about the nature of science. First it shows how historicizing science in the classroom can improve the pedagogical experience of science students and might even help them turn into more effective professional practitioners of science. Then it examines how historians of science can support the scientific education of the general public at a time when debates over "intelligent design" are raising major questions over the kind of science that ought to be available to children in their school curricula. It concludes by considering further work that might be undertaken to show how history of science could be of more general educational interest and utility, well beyond the closed academic domains in which historians of science typically operate.

Cyanobacteria are responsible for producing microcystins (MCs), a class of potent and structurally diverse toxins, in freshwater systems around the world. While microcystins have been studied for over 50 years, the diversity of their chemical forms and how this variation is encoded at the genetic level remain poorly understood, especially within natural populations of cyanobacterial harmful algal blooms (cyanoHABs).

Abstract. Recent global water quality crises point to an urgent need for greater understanding of cyanobacterial harmful algal blooms (cHABs) and their drivers. Nearshore areas of Lake Erie such as Sandusky Bay may become seasonally limited by nitrogen (N) and are characterized by distinct cHAB compositions (i.e., Planktothrix over Microcystis). This study investigated phytoplankton N uptake pathways, determined drivers of N depletion, and characterized the N budget in Sandusky Bay. Nitrate (NO3-) and ammonium (NH4+) uptake, N fixation, and N removal processes were quantified by stable isotopic approaches. Dissimilatory N reduction was a relatively modest N sink, with denitrification, anammox, and N2O production accounting for 84, 14, and 2 % of sediment N removal, respectively. Phytoplankton assimilation was the dominant N uptake mechanism, and NO3- uptake rates were higher than NH4+ uptake rates. Riverine N loading was sometimes insufficient to meet assimilatory and dissimilatory demands, but N fixation alleviated this deficit. N fixation made up 23.7–85.4 % of total phytoplankton N acquisition and indirectly supports Planktothrix blooms. However, N fixation rates were surprisingly uncorrelated with NO3- or NH4+ concentrations. Owing to temporal separation in sources and sinks of N to Lake Erie, Sandusky Bay oscillates between a conduit and a filter of downstream N loading to Lake Erie, delivering extensively recycled forms of N during periods of low export. Drowned river mouths such as Sandusky Bay are mediators of downstream N loading, but climate-change-induced increases in precipitation and N loading will likely intensify N export from these systems.

Cyanobacteria harmful algal blooms produce many toxic secondary metabolites called cyanotoxins. The most studied group of cyanotoxins are microcystins (MC), with over 300 congeners reported. MC-LR is the most studied congener because of its abundance and toxicity. Recent toxicology studies suggest that more hydrophobic MC congeners such as MC-LA, MC-LF, and MC-LW may be less abundant but up to seven times more toxic than MC-LR, whereas, MC-RR's toxicity is only one-fifth that of MC-LR. Hence, understanding the environmental stressors that change the MC congener profile is critical to assessing the negative impact on environmental and human health. A two-year field and experimental study investigated seasonal and spatial changes of MC congener profiles in the western basin of Lake Erie. Both studies showed that nitrogen enrichment favored the production of nitrogen-rich MC-RR (C49H75N13O12). The field study showed that nitrogen depletion favored the low-nitrogen MC-LA (C46H67N7O12). MC-LR (a medium N level, C49H75N10O12) accounted for ∼30% to 50% of the total MC concentration and was stable across nitrogen concentrations. Using the relative toxicity and concentrations of each MC congener, both LC-MS/MS and ELISA overestimated the toxicity early bloom (July) and underestimated it late bloom (September). On 24 July 2019, highly toxic MC-LW and MC-LF were detected at nearshore stations with relative toxicity exceeding drinking water standards. This study demonstrated that the less toxic, high nitrogen MC-RR dominated under nitrogen-replete conditions in the early season, whereas the more toxic, less nitrogen MC-LA dominated under nitrogen-limited conditions later in the season.

Cyanobacterial harmful algal bloom (CyanoHAB) proliferation is a global problem impacting ecosystem and human health. Western Lake Erie (WLE) typically endures two highly toxic CyanoHABs during summer: a Microcystis spp. bloom in Maumee Bay that extends throughout the western basin, and a Planktothrix spp. bloom in Sandusky Bay. Recently, the USA and Canada agreed to a 40% phosphorus (P) load reduction to lessen the severity of the WLE blooms. To investigate phosphorus and nitrogen (N) limitation of biomass and toxin production in WLE CyanoHABs, we conducted in situ nutrient addition and 40% dilution microcosm bioassays in June and August 2019. During the June Sandusky Bay bloom, biomass production as well as hepatotoxic microcystin and neurotoxic anatoxin production were N and P co-limited with microcystin production becoming nutrient deplete under 40% dilution. During August, the Maumee Bay bloom produced microcystin under nutrient repletion with slight induced P limitation under 40% dilution, and the Sandusky Bay bloom produced anatoxin under N limitation in both dilution treatments. The results demonstrate the importance of nutrient limitation effects on microcystin and anatoxin production. To properly combat cyanotoxin and cyanobacterial biomass production in WLE, both N and P reduction efforts should be implemented in its watershed.

Many attempts have been made to describe the activity of the internal trunk-loading components (muscles and intra-abdominal pressure) in response to external forces acting on the trunk, as is often the case in the workplace. Most models that describe the activity of these internal components are static and do not consider the time series of events that occurs during performance of a task under dynamic conditions. This research has investigated the time sequence activity of ten trunk muscles and intra-abdominal pressure in ten males as they produced sagittally symmetric maximum trunk extension motions (lifting motions) at different velocities. These exertions include an isometric exertion and isokinetic exertions equal to 25, 50, 75 and 100% of a subject's maximum extension velocity. Several event times were noted for each internal trunk-loading component, and hypothesis tests were performed to determine which of these event times were statistically different from each other under the various motion conditions. This information was used to construct networks of internal trunk-loading activities under the various motion conditions. Time-series events that occur under all conditions, as well as those that changed as a function of velocity, have been identified. This information will be useful for the construction of dynamic internal trunk models, and will facilitate the assessment of dynamic loading of the lumbar spine in the workplace.

The US Midwest is expected to experience higher intensity rainfall events along with an increased chance of drought during the mid- and late 21st century under projected future climate scenarios. Development of strategies to mitigate the impact of these projected changes on agricultural production and environmental quality is important for ensuring agricultural resiliency to future climate. This study used the DRAINMOD hydrologic model to simulate subsurface drainage discharge at a field site in the headwaters of the Western Lake Erie Basin using future climate patterns projected by 20 general circulation models. Despite projected increases in rainfall, by the late twenty-first century, subsurface discharge was projected to decrease 7% and 11% under representative concentration pathway (RCP) 4.5 and RCP 8.5, respectively. Reductions in subsurface discharge were attributed to increased temperature and evapotranspiration. The performance of controlled drainage was not projected to change on an annual basis throughout the next century. The benefits of controlled drainage systems as an agricultural best management practice were still evident under the projected climate change of the next century. The role of controlled drainage as a means to potentially retain more crop available water in the soil profile could become critically important under future climate conditions.

Many attempts have been made to describe the activity of the internal trunk-loading components (muscles and intra-abdominal pressure) in response to external forces acting on the trunk, as is often the case in the workplace. Most models that describe the activity of these internal components are static and do not consider the time series of events that occurs during performance of a task under dynamic conditions. This research has investigated the time sequence activity of ten trunk muscles and intra-abdominal pressure in ten males as they produced sagittally symmetric maximum trunk extension motions (lifting motions) at different velocities. These exertions include an isometric exertion and isokinetic exertions equal to 25, 50, 75 and 100% of a subject's maximum extension velocity. Several event times were noted for each internal trunk-loading component, and hypothesis tests were performed to determine which of these event times were statistically different from each other under the various motion conditions. This information was used to construct networks of internal trunk-loading activities under the various motion conditions. Time-series events that occur under all conditions, as well as those that changed as a function of velocity, have been identified. This information will be useful for the construction of dynamic internal trunk models, and will facilitate the assessment of dynamic loading of the lumbar spine in the workplace.

A content analysis of audiotapes from 42 counseling supervisory dyads examined the effects of supervisor and supervisee gender on the influence strategies used in the session. Gender of the supervisor was not related to influence strategy. Supervisors of both genders were significantly more likely to accept or build upon the ideas generated by female supervisees and asked for more opinions from male supervisees. Male supervisees gave significantly more suggestions than did female supervisees, and female supervisees praised their supervisors more often than did male supervisees. Also, age differences between supervisor and supervisee interacted with gender to affect influence strategies used in the supervisory dyad.

Abstract Cyanobacterial biomass forecasts currently cannot predict the concentrations of microcystin, one of the most ubiquitous cyanotoxins that threaten human and wildlife health globally. Mechanistic insights into how microcystin production and biodegradation by heterotrophic bacteria change spatially and throughout the bloom season can aid in toxin concentration forecasts. We quantified microcystin production and biodegradation during two growth seasons in two western Lake Erie sites with different physicochemical properties commonly plagued by summer Microcystis blooms. Microcystin production rates were greater with elevated nutrients than under ambient conditions and were highest nearshore during the initial phases of the bloom, and production rates were lower in later bloom phases. We examined biodegradation rates of the most common and toxic microcystin by adding extracellular stable isotope‐labeled microcystin‐LR (1 μ g L −1 ), which remained stable in the abiotic treatment (without bacteria) with minimal adsorption onto sediment, but strongly decreased in all unaltered biotic treatments, suggesting biodegradation. Greatest biodegradation rates (highest of −8.76 d −1 , equivalent to the removal of 99.98% in 18 h) were observed during peak bloom conditions, while lower rates were observed with lower cyanobacteria biomass. Cell‐specific nitrogen incorporation from microcystin‐LR by nanoscale imaging mass spectrometry showed that a small percentage of the heterotrophic bacterial community actively degraded microcystin‐LR. Microcystin production and biodegradation rates, combined with the microcystin incorporation by single cells, suggest that microcystin predictive models could be improved by incorporating toxin production and biodegradation rates, which are influenced by cyanobacterial bloom stage (early vs. late bloom), nutrient availability, and bacterial community composition.

Abstract This article presents new data on the characteristics and business operations of Ohio's Lake Erie charter fishing industry. To monitor changes in the industry, I surveyed a random sample of 315 licensed Ohio charter captains by mail in October and November 1994. The number of Ohio charter captains, reacting to changing Lake Erie environmental and business conditions, grew rapidly in the 1980s, peaking at 1,211 captains in 1990. Concerns of charter captains have changed throughout the years. In 1994, charter market demand and business cost factors were the top concerns. Ohio captains remaining in the industry in 1994 have improved their cash flow and economic viability. Increases in operating costs have been offset by increased revenues and reduced capital costs, the latter caused partially because captains have kept their boats longer. In 1994, only those captains making 41 or more trips had economically viable enterprises that more than offset the costs of owning a pleasure boat. This is an impr...

Richards, R. Peter, Ibrahim Alameddine, J. David Allan, David B. Baker, Nathan S. Bosch, Remegio Confesor, Joseph V. DePinto, David M. Dolan, Jeffrey M. Reutter, and Donald Scavia, 2012. Discussion –“Nutrient Inputs to the Laurentian Great Lakes by Source and Watershed Estimated Using SPARROW Watershed Models” by Dale M. Robertson and David A. Saad. Journal of the American Water Resources Association (JAWRA) 1‐10. DOI: 10.1111/jawr.12006 Abstract: Results from the Upper Midwest Major River Basin (MRB3) SPARROW model and underlying Fluxmaster load estimates were compared with detailed data available in the Lake Erie and Ohio River watersheds. Fluxmaster and SPARROW estimates of tributary loads tend to be biased low for total phosphorus and high for total nitrogen. These and other limitations of the application led to an overestimation of the relative contribution of point sources vs. nonpoint sources of phosphorus to eutrophication conditions in Lake Erie, when compared with direct estimates for data‐rich Ohio tributaries. These limitations include the use of a decade‐old reference point (2002), lack of modeling of dissolved phosphorus, lack of inclusion of inputs from the Canadian Lake Erie watersheds and from Lake Huron, and the choice to summarize results for the entire United States Lake Erie watershed, as opposed to the key Western and Central Basin watersheds that drive Lake Erie’s eutrophication processes. Although the MRB3 SPARROW model helps to meet a critical need by modeling unmonitored watersheds and ranking rivers by their estimated relative contributions, we recommend caution in use of the MRB3 SPARRROW model for Lake Erie management, and argue that the management of agricultural nonpoint sources should continue to be the primary focus for the Western and Central Basins of Lake Erie.