Does allochthonous disscolved organic matter increase during summer algal bloom conditions in an agricultural reservoir?

Cyanobacterial harmful algal blooms (cyanoHABs) are increasing in frequency worldwide. CyanoHABs can produce toxins (e.g., microcystin), which can be a contaminant in recreational and drinking water reservoirs. Reservoirs have been increasing worldwide, highlighting the importance of understanding their biogeochemical processes. Dissolved organic matter (DOM) is a reactive and readily available source of nitrogen (N) and carbon (C) for microbes in aquatic systems, however, the relationships between DOM and cyanoHABs remain relatively unexplored in agricultural reservoirs. Our primary objective is to determine if an increase in allochthonous DOM leads to an increase in autochthonous DOM during a summer cyanobacterial bloom event in a warm monomictic agricultural reservoir. Water samples were collected two to three times per week from June 21st until October 5th, 2018 and analyzed for algal biomass and community composition, DOM quality and quantity. A variety of spectral parameters were used to determine DOM quality. One cyanobacterial bloom event was detected on July 16th. Maximum microcystin concentration for the sampling period was 0.68 [mu]gL-1 which is well under the EPA recommended recreational limit (8 [mu]gL-1). Dissolved organic carbon (DOC) concentrations were positively correlated with high amounts of terrestrial DOM. DOC concentrations and a350 also correlated positively with microcystin concentrations. Specific UV absorbance at 254nm (SUVA254) correlated positively with Chl-a (r=0.37, p=0.033). Our findings indicate that high DOM quantity has a significant relationship to microcystin concentration, which has negative implications for recreation and drinking water quality.Kyra M. Flora, Ruchi Bhattacharya, and Rebecca L. North (School of Natural Resources, University of Missouri, Columbia

ADHD and College Students: Experiencing an Illness Career

This study examines one particular example of an illness career in a sociologically important yet understudied population: university students who have been diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) and certified as eligible for support services by a university clinic. Most adults in America have visited a physician at least once in their lifetime. In our culture this is a regular, taken-for-granted activity for those who feel sick. But how does someone arrive at the decision to seek expert medical help? Sociological researchers have demonstrated that this process is actually quite complex, involving a series of decision-making steps that together can be analyzed as stages in an "illness career." Using qualitative interviews, I examined the experiences and processes that ADHD students pass through. I use the ideas of the sick role, illness career and gatekeeper to inform my results. Through my analysis, I have created a model for the illness career that contrasts with the traditional linear stages by viewing the different aspects of the career as intertwined. Regarding ADHD, I discovered that this disorder shifts from being other-diagnosed to self-diagnosed as a student progresses through the educational system. I also add insight to structural responses, and to the living experience of the ADHD diagnosed individual

Stagnate summers : climate induced changes in physical mixing parameters in Missouri reservoirs

Lakes and reservoirs are important environmental sentinels for climate change. As air temperatures rise so do the temperatures of these water bodies affecting their physical, chemical, and biological properties. Being used for drinking water supplies, fisheries, and human recreation, these long term potential changes can be an important factor for their use. Climate change has been associated with altering physical reservoir parameters, such as mixing depth, water temperatures, and water chemistry. Using a historical dataset to find both break points and monotonic trends that may indicate climate having influenced our reservoirs we found little in terms of monotonic trends. However, we did witness changes in all systems in regards to break points for almost every parameter. Our systems cannot directly correlate to having had climate change based effects, as we can neither support or refute its evidence in our reservoirs as changes relating to climate do not only impact physical parameters but also animal and plant communities, and social factors such as use (influenced by cyanobacteria blooms). It is even plausible that increased in reservoir production and turbidity could lead to shifts in physical trends that would otherwise be different in non-affected reservoirs. Over all more information is needed to create a better picture of exactly how climate change is impacting the physical mixing parameters in Missouri reservoirs as they are complex and varied systems.Cody Kimbell, John R. Jones, Daniel Obrecht, and Rebecca North (University of Missouri, Columbia

Sex differences in the development of spatial behavior in montane voles : experiential and hormonal influences

In animals with polygamous mating systems, in which males' territories overlap the territories of two or more females, males perform spatial tasks with fewer errors than do females. While it has been suggested that these differences persist due to natural selection, this does not explain how they develop. In this study, I investigated the development of sex differences in spatial abilities of montane voles (Microtus montanus), a polygamous species, as influenced by environmental and hormonal factors. Litters were culled to three same-sex pups and raised in clear plastic cages, either small (21x20x23cm = Restricted) or large with objects for exploration (21x38x48cm = Expanded) . The pups were weaned at 21 days of age and remained in their natal environment

Chemical mass transport between fluid fine tailings and the overlying water cover of an oil sands end pit lake

NSERC Grant No. CRDPJ 476388; NSERC Grant No. IRCPJ 428588–11Peer ReviewedFluid fine tailings (FFT) are a principal by-product of the bitumen extraction process at oil sands mines. Base Mine Lake (BML)—the first full-scale demonstration oil sands end pit lake (EPL)—contains approximately 1.9 3 108 m^3 of FFT stored under a water cover within a decommissioned mine pit. Chemical mass transfer from the FFT to the water cover can occur via two key processes: (1) advection-dispersion driven by tailings settlement; and (2) FFT disturbance due to fluid movement in the water cover. Dissolved chloride (Cl) was used to evaluate the water cover mass balance and to track mass transport within the underlying FFT based on field sampling and numerical modeling. Results indicated that FFT was the dominant Cl source to the water cover and that the FFT is exhibiting a transient advection-dispersion mass transport regime with intermittent disturbance near the FFT-water interface. The advective pore water flux was estimated by the mass balance to be 0.002 m^3 m^-2 d^-1, which represents 0.73 m of FFT settlement per year. However, the FFT pore water Cl concentrations and corresponding mass transport simulations indicated that advection rates and disturbance depths vary between sample locations. The disturbance depth was estimated to vary with location between 0.75 and 0.95 m. This investigation provides valuable insight for assessing the geochemical evolution of the water cover and performance of EPLs as an oil sands reclamation strategy

Untersuchungen von Beugesehnennähten mittels Bildsequenzanalyse im Experiment

Im Rahmen dieser Arbeit werden die Ergebnisse aus Zugversuchen an Schweinesehnen, die mit verschiedenen Nahtmaterialien und den gängigen Nahttechniken für Beugesehnen der Hand genäht wurden, vorgestellt. Schwerpunkt der Untersuchungen ist die Ermittlung und Dokumentation der Reißfestigkeit der Naht und die Spaltbildung an der Kontaktstelle der genähten Sehnenstümpfe mittels biomechanischer Versuche. Das Eintreten der Spaltbildung und des Nahtrisses wird durch videotechnische Aufzeichnungen, die den eigentlichen Messvorgang an der Universalprüfmaschine begleiten, exakt dokumentiert (Bildsequenzanalyse). Die Bildsequenzanalyse stellt gegenüber den in der Literatur dokumentierten Methoden eine wesentliche Fort- bzw. Neuentwicklung zur Ermittlung der Spaltstabilität und der Reißfestigkeit von genähten Sehnen dar. Die Auswertung der Versuche mittels Bildsequenzanalyse wurde für 12 verschiedene Nahttechnik/Nahtmaterial-Kombinationen durchgeführt. Nach Entwicklung und Anfertigung einer neuen Einspannvorrichtung für die Sehnen, die eine optimale Festhaltung der Sehnenstümpfe gewährleistete, erfolgte die systematische Durchführung von Bildsequenzanalysen für gängige Sehnennaht-Techniken mit verschiedenen Fäden. Auf Grundlage der biomechanischen Versuche und der Weiterentwicklung bisheriger Kenntnisse zur Beugesehnennaht konnte im Rahmen dieser Arbeit eine optimierte bzw. eine neue Nahttechnik entwickelt werden (Marburger Sehnennaht I und II), die eine frühe postoperative Mobilisierung durch entsprechende Nahtfestigkeiten ermöglicht, eine gute Gleitfunktion aufweist sowie durch Erhaltung der Gefäßversorgung der Sehne einen sicheren Heilungsprozess gewährleistet. Die Ergebnisse der biomechanischen Versuche mit der Marburger Sehnennaht I und II sind in dieser Arbeit detailliert dokumentiert. Der Vergleich mit den gängigen Sehnennaht-Techniken zeigt, dass die Marburger Sehnennaht eine hohe Reißfestigkeit und die beste Spaltstabilität besitzt

Year-round patterns in bacterial production and biomass in Lake Simcoe, Ontario, Canada: are heterotrophic bacteria a significant contributor to low hypolimnetic oxygen?

Bacteria serve an important function in aquatic environments and are associated with nutrient regeneration, carbon (C) metabolism, and secondary production. This is the first study to measure heterotrophic bacterial production, abundance, biomass, and biovolume in Lake Simcoe, Ontario. Excessive phosphorus loading resulting in low hypolimnetic oxygen concentrations has impacted the cold-water fishery in Lake Simcoe. We tested the hypothesis that bacteria contributed to dissolved oxygen declines in Lake Simcoe and examined the environmental factors impacting bacterial activity. Spatial and temporal variations in the microbial community were measured from June 2010 to July 2011. A dual-isotope method (3H-TdR and 14C-leu) was used, resulting in mean (± standard deviation) annual epilimnetic bacterial production estimates of 0.130 ± 0.173 and 0.268 ± 0.304 µg C L−1 h−1, respectively. The mean annual bacterial abundance was 1.49 ± 1.53 cells × 109 L−1, with a mean biomass of 1.21 ± 1.34 µg C L−1 and a mean biovolume of 0.0043 ± 0.0030 µm3 cell−1. These estimates had distinct seasonal patterns, with consistently lower bacterial activity in the winter relative to the spring, summer, and fall. Differences between epilimnetic and hypolimnetic bacterial activity were inconsistent for the 4 bacterial parameters measured. Lake temperature, chlorophyll a, and dissolved organic C concentrations were the most significant factors influencing the annual epilimnetic patterns in the examined bacterial parameters. Annual bacterial production was low in Lake Simcoe and does not seem to be a major contributor to the low hypolimnetic oxygen concentrations in the lake

Freezing plants : exploring the effects of freeze thaw cycles on macrophyte phosphorus release

Every year following the cold winter freeze comes the spring thaw, and with it comes an influx of nutrients that can cause eutrophication problems; even in high nutrient systems. We identified a potential source of nutrients released during the winter freeze; aquatic macrophytes and aimed to determine the quantity of total phosphorus (TP) they release. Specifically, cattails and reeds (Typha and Juncus, respectively). Stalks were harvested from 3 different sites; a pond with an agriculturally dominated watershed, the beginning of a wetland used to treat effluent waste water, and a site further along in the wetland treatment process. Samples from each site were split into four different sample types: wet freeze, dry freeze, wet control, and dry control. Control and freeze samples were placed in at 1.6[degree]C and -1[degree]C respectively, and left for equal amounts of time averaging 31.375 hours (SD 10.25). After treatment, residual water samples were analyzed for total phosphorus concentrations. Results showed that freeze thaw cycles (FTCs) did not induce TP release from macrophytes tested in the lab. These results suggest that the use of macrophytes as a sink for nutrients is a beneficial practice that managers should continue to employ.Matthew Sauer, Osama Ahmed, Jeremy Leathers, Katy Nugent, Tyler Prentice, Helen Baulch, Nora Casson, Jason Venkiteswarab, Colin Whitfield and Rebecca North (University of Missouri, University of Saskatchewan, Wilfred Laurier University, University of Winnipeg

Diabetic Retinopathy in Newly Diagnosed Subjects With Type 2 Diabetes Mellitus: Contribution of β-Cell Function

Purpose: The association of hyperglycemia and diabetic retinopathy (DR) in established type 2 diabetes mellitus (T2DM) subjects is well accepted. However, the association between β-cell responsiveness and insulin sensitivity leading to fasting and postprandial hyperglycemia with DR in newly diagnosed treatment-naïve T2DM subjects remain unreported. Methods: A total of 544 newly diagnosed treatment-naïve T2DM subjects were screened for DR (digital photography) and underwent a standardized meal tolerance test. Serial plasma glucose and insulin levels were measured, and fasting (M0) and postprandial β-cell responsiveness calculated Calculating Pancreatic Response Program along with homeostasis model assessment-β cell function (HOMA-B) and HOMA-Insulin Sensitivity. A subgroup of 201 subjects also underwent a frequently sampled IV glucose tolerance test and the acute insulin response to glucose, insulin sensitivity, and glucose effectiveness (SG) estimated (MINMOD model). Results: A total of 16.5% (90) subjects had DR at diagnosis. Subjects with DR had significantly reduced M0, HOMA-B and SG leading to higher fasting and postprandial (2 hour) glucose and significantly lower fasting and postprandial (2 hour) insulin. Factors independently associated with DR in multivariate logistic regression analysis were M0, HOMA-B, and SG with fasting and postprandial (2 hour) glucose and insulin. There was no statistical difference in glycated hemoglobin, systolic blood pressure, acute insulin response to glucose, and insulin sensitivity between those with or without DR. Principal Conclusions: In this cohort of newly diagnosed T2DM subjects, DR is associated with reduced β-cell responsiveness, resulting from β-cell failure rather than insulin resistance, leading to fasting and postprandial hyperglycemia and hypoinsulinemi

Burping wetlands : quantifying greenhouse gas ebullition rates across a range of sediment types and characteristics, water quality variables, and land use

Aquatic ecosystems are a source of greenhouse gases (GHG) to the atmosphere. One pathway of this GHG release is ebullition, or bubbling, from aquatic sediments. The contribution of ebullition is often underestimated in global GHG budgets, as it is rarely included in GHG emission measurements. The ebullition pathway can account for up to 67 percent of methane emissions from water bodies. We aim to determine the factors that influence ebullition of methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O), including sediment characteristics, water quality characteristics, and land use. Our study ponds are in urban, agricultural, and woodland areas. We found that N2O flux rates are significantly lower than CH4 and CO2 flux rates across all study ponds. We also found that urban areas have higher GHG flux rates, which is correlated with low organic matter content. Understanding the factors influencing GHG ebullition from aquatic ecosystems will give us a broader understanding of the significance of their contribution to global GHG budgets in a changing climate.Jannice Newson, Jaylen Bragg, Hamza Amjad, Lauren Dyck, Selena Komarevich, Colin Whitfield, Helen Baulch, Jason Venkiteswaran, Nora Casson, Richard Helmle, and Rebecca L. North (University of Missouri, University of Winnipeg, University of Saskatchewan, Wilfred Laurier University