Nutrient contamination from non-point sources: Dissolved nitrate and ammonium in surface and subsurface waters at EKU Meadowbrook Farm, Madison County, Kentucky

Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University’s Meadowbrook Farm, contributes dissolved nitrogen into the Muddy Creek watershed. To assess the concentrations of dissolved nitrogen compounds, we sampled waters draining from the Farm as springs, runoff, and subsurface pipe drainage as well as Muddy Creek on six days from May to August 2016 under a variety of weather conditions. We measured dissolved nitrate (NO­3-) and ammonium (NH4+) using standard colorimetric methods and spectrophotometry with an accuracy of ~0.1 mg/L. Nitrate was the dominant nutrient contaminant, whereas ammonium was often absent in water samples. Nitrate levels were usually \u3c2 mg/L in surface waters. Springs and some tributaries exhibited the largest nitrate values generally ranging from 7.0 to 14.3 mg/L. Ammonium displayed sporadic concentration spikes between 2.0 and 4.3 mg/L. Dissolved nitrogen concentrations responded to rainfall. We saw a general decrease of nitrogen concentration during dry periods, especially in Muddy Creek and an increase in nitrogen concentration under wetter conditions. Springs maintained high nitrogen concentrations regardless of different rainfall conditions. We compared our nitrogen measurements from Meadowbrook Farm to national values. For surface waters, the median nitrate concentration was 2.7 mg/L, lower than the national median (3.8 mg/L), whereas ammonium values were 0.2 mg/L, higher than the national median (0.1 mg/L). In groundwater, we found the median nitrate concentration was 3.9 mg/L, higher than the national median (3.4 mg/L), whereas the median ammonium concentration was 0.05 mg/L, higher than the national median (0.02 mg/L)

Using The-Math-You-Need modules in a general education, oceanography course

The Math You Need (TMYN) is a series of on-line tutorials designed for students to increase their mathematical abilities while taking geology and other science courses. The aim of the program is to increase the quantitative abilities of students while demonstrating mathematical applications in an effort to make students more comfortable with and aware of the utility of mathematics. Over two semesters, we implemented targeted-TMYN modules into a general-education oceanography course that is typically populated by non-science majors with a wide variety of mathematical skills before calculus. Students participate voluntarily in TMYN modules with extra credit given for their successful completion. Every class day in the course involves exercises and/or a laboratory that applies oceanographic concepts into which we frequently weave elementary mathematics; also, quantitative questions appear on course exams. For example, understanding rates is particularly fundamental, so exercises frequently concentrate on rate calculations and re-arrangement of simple rate equations and this in-class instruction is complemented by appropriate TMYN modules. To reinforce the importance and utility of mathematics, the instructor continually makes connections between course material and TMYN tutorials. Pedagogical results are mostly positive. Because participation in TMYN modules is voluntary, two-thirds of students participate partially or wholly in the modules; the complementary fraction do not access a single module. We use pre- and post-tests to recognize gains in student mathematical competence. About one third of students either have lower or no change in performance whereas the balance exhibit varying gains. Some students’ scores saltate markedly by doubling, whereas other students achieve more modest gains. Not surprisingly, larger gains tend to be seen by students that have completed more modules with better scores, but this tendency is not absolute. TMYN modules are looked upon favorably by students. The preponderance of students think that TMYN modules improved their mathematical abilities and helped with the class. We plan continued use of TMYN modules with the goal of augmenting student participation, in anticipation of associated improvement in quantitative skills

Geochemical Characteristics and Storm Dynamics of Surface Waters and Groundwater at Eastern Kentucky University’s Meadowbrook Farm, Madison County, Kentucky

Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University’s Meadowbrook Farm raises crops and livestock, contributing dissolved nutrients to the neighboring Muddy Creek watershed. Consequently, the Farm is developing methods to sequester and limit nutrient contamination. Before phosphorous sequestration methods can be tested, the geochemistry of surface water and groundwater on the Farm need to be better understood to determine hydrological pathways. We use naturally-occurring, dissolved cations as tracers to identify the contribution of different water sources and interpret storm events. Water samples taken from springs (groundwater), surface water, and storm water on the Farm were analyzed for dissolved cations via ICP-OES for sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+). A V-notch weir was used to quantify volumetric flow for a rain event during tropical storm Cindy. Ca2+ and Mg2+ concentrations (55.5-80.0 mg/L and 21.7-32.5 mg/L, respectively) and lower Na+ and K+ concentrations (9.6-14.8 mg/L and 1.7-18.3 mg/L, respectively) seem to predominantly characterize source groundwater. During Cindy, Ca2+, Mg2+, and Na+ decreased with increasing volumetric flow rate, likely indicating dilution of groundwater. However, K+ exhibited elevated concentrations that spike concurrently with initial discharge peaks and then progressively decrease over the duration of the storm event. We hypothesize that initial K+ increases represent significant overland flow followed by dilution with groundwater and/or continued runoff. If nutrient runoff behavior is similar to potassium, those nutrients should exhibit peak export with initial runoff

Characterization of groundwater and surface water geochemistry in an agricultural setting at EKU Meadowbrook Farm, Madison County, Kentucky

Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University (EKU) Meadowbrook Farm raises crops and livestock, which contribute dissolved nutrients to the neighboring Muddy Creek watershed. Consequently, the Farm is developing methods to sequester phosphorous and limit nutrient contamination. Before phosphorous sequestration methods can be tested, Farm surface water and groundwater geochemistry must be better understood to determine hydrological pathways for nutrients. We use naturally-occurring dissolved cations, pH, oxidation-reduction potential (ORP), specific conductivity (SC), dissolved oxygen (DO%), total hardness, and alkalinity as chemical tracers to parse the contribution of dissolved ions from different water sources, to recognize different water source chemistries, and to interpret storm events. To measure discharge from a proximal, intermittent stream that drains a representative and critical portion of the Farm, we used an instrumented, V-notch weir to examine storm-water flow during Tropical Storm Cindy (June 22-25, 2017). Water samples taken from springs (groundwater), surface water, and storm water on the Farm were analyzed for various dissolved constituents. Dissolved cations were measured via ICP-OES (ACT Labs) for sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+). pH, ORP, SC, and DO% were determined with YSI and Vernier probes. Alkalinity and total hardness were measured via the bromocresol green - methyl red and the EDTA digital titration methods, respectively. Dissolved ammonium (NH4+), nitrate (NO3-), and phosphate (PO43-) concentrations were determined by colorimetry with a UV-VIS spectrophotometer via the sodium hypochlorite, cadmium reduction, and ascorbic acid methods, respectively. Both groundwater and surface water sources exhibit similar ranges of pH (neutral to basic), ORP (oxidizing), alkalinity, total hardness, DO%, and SC. Source waters generally have high Ca2+ and Mg2+, and low K+, Na+, PO43-, and NH4+ concentrations. This strongly suggests that background chemistries of source groundwater and surface water are controlled by local limestone bedrock dissolution. Groundwater is further characterized by relatively high NO3- concentrations and low temperatures; in contrast, surface waters exhibit higher temperatures and lower NO3- concentrations. During the Cindy event, concentration of Ca2+, Mg2+, and Na+ within baseline source waters decreased with increasing discharge through the weir (Fig. 1), along with SPC, pH, and alkalinity. This behavior represents dilution of Farm groundwater by storm precipitation and subsequent overland flow. However, K+ increased from baseline concentrations, spiking concurrently with increased discharge through the weir, and then progressively decreased in magnitude over the duration of the storm (Fig. 2). These data suggest that K+ was flushed from soil by rain waters. Nutrient concentrations increase with increased discharge indicating transport by surface runoff. For example, PO43- concentrations closely track and are proportional to discharge, which suggests PO43- transport from the surficial soil substrate via flushing by precipitation (Fig. 3). NO3- exhibited nearly identical transport behavior as K+; concentration spikes occur simultaneously with K+ and discharge. However, NO3- levels reached a higher baseline concentration than pre-storm levels. The Cindy event suggests infiltration and retention of NO3- within soil and groundwater during fair weather, initial flushing during the rain event, and then prolonged NO3- release from Farm soil and groundwater. Background concentration of NH4+ is generally 0.0 to 0.2 mg/L. Immediately prior to water flow over the weir during the Cindy event, concentrations were unusually high (~1.7 mg/L). During the first storm pulse, these high concentrations decreased significantly to \u3c0.4 mg/L. Later in the main storm event, NH4+ tracked discharge from the weir and afterward returned to typical background concentrations. This behavior suggests rapid release of NH4+ from soil followed by accumulation within the weir pool and then subsequent flushing during the precipitation event

Revised Point of Departure Design Options for Nuclear Thermal Propulsion

In an effort to further refine potential point of departure nuclear thermal rocket engine designs, four proposed engine designs representing two thrust classes and utilizing two different fuel matrix types are designed and analyzed from both a neutronics and thermodynamic cycle perspective. Two of these nuclear rocket engine designs employ a tungsten and uranium dioxide cermet (ceramic-metal) fuel with a prismatic geometry based on the ANL-200 and the GE-710, while the other two designs utilize uranium-zirconium-carbide in a graphite composite fuel and a prismatic fuel element geometry developed during the Rover/NERVA Programs. Two engines are analyzed for each fuel type, a small criticality limited design and a 111 kN (25 klbf) thrust class engine design, which has been the focus of numerous manned mission studies, including NASA's Design Reference Architecture 5.0. slightly higher T/W ratios, but they required substantially more 235U

Localisation of the human hSuv3p helicase in the mitochondrial matrix and its preferential unwinding of dsDNA

We characterised the human hSuv3p protein belonging to the family of NTPases/helicases. In yeast mitochondria the hSUV3 orthologue is a component of the degradosome complex and participates in mtRNA turnover and processing, while in Caenorhabditis elegans the hSUV3 orthologue is necessary for viability of early embryos. Using immunofluorescence analysis, an in vitro mitochondrial uptake assay and sub‐fractionation of human mitochondria we show hSuv3p to be a soluble protein localised in the mitochondrial matrix. We expressed and purified recombinant hSuv3p protein from a bacterial expression system. The purified enzyme was capable of hydrolysing ATP with a Km of 41.9 µM and the activity was only modestly stimulated by polynucleotides. hSuv3p unwound partly hybridised dsRNA and dsDNA structures with a very strong preference for the latter. The presented analysis of the hSuv3p NTPase/helicase suggests that new functions of the protein have been acquired in the course of evolution

Nutrient contamination from non-point sources: Dissolved nitrate and ammonium in surface and subsurface waters at EKU Meadowbrook Farm, Madison County, Kentucky

Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. We assayed dissolved nutrient levels in surface and subsurface waters of Eastern Kentucky University’s Meadowbrook Farm in order to assess levels of dissolved nutrients leaving its farmland and draining into the Muddy Creek watershed. The Farm raises both crops and livestock so that nutrient sources include fertilizer and manure. We sampled springs, runoff, and subsurface pipe drainage as well as Muddy Creek on six days from May to August 2016 under a variety of weather conditions. Using established, standard colorimetric methods, we measured nitrate (NO3-; cadmium reduction method) and ammonium (NH4+; sodium hypochlorate method) via spectrophotometry with a precision and accuracy of ~0.1 mg/L. Nitrate was the dominant dissolved nitrogen species whereas ammonium was often absent in water samples. Nitrate levels were typically \u3c2 mg/L N- N- NO3 with the largest values between 7.0 and 14.3 mg/L. Springs and some runoff samples had higher nitrate values. Ammonium generally ranged between 0.0 and 0.5 mg/L N- NH4 with concentration spikes between 2.0 and 4.3 mg/L, but from no consistent source. Dissolved nitrogen concentration values responded to rainfall. Generally, nitrate concentrations increased more than ammonium concentrations during wetter periods. Spring samples maintained higher nitrogen concentrations regardless of different rainfall conditions. Lastly, nitrate contamination was significantly lower than composite national values from streams draining agricultural lands, whereas ammonium was about equal to the median national average. Median nitrate concentration was ~1.8 mg/L N- NO3 compared to the national value of ~2.8 mg/L, whereas the value for pristine streams is 0.24 mg/L N- NO3 (Dubrovsky et al., 2010). Median ammonium values from both data sets are ~0.1 mg/L N- NH4; the national value from pristine streams is ~0.025 mg/L N

Life in the Dark: Phylogenetic and Physiological Diversity of Chemosynthetic Symbioses

Possibly the last discovery of a previously unknown major ecosystem on Earth was made just over half a century ago, when researchers found teaming communities of animals flourishing two and a half kilometers below the ocean surface at hydrothermal vents. We now know that these highly productive ecosystems are based on nutritional symbioses between chemosynthetic bacteria and eukaryotes and that these chemosymbioses are ubiquitous in both deep-sea and shallow-water environments. The symbionts are primary producers that gain energy from the oxidation of reduced compounds, such as sulfide and methane, to fix carbon dioxide or methane into biomass to feed their hosts. This review outlines how the symbiotic partners have adapted to living together. We first focus on the phylogenetic and metabolic diversity of these symbioses and then highlight selected research directions that could advance our understanding of the processes that shaped the evolutionary and ecological success of these associations

Slavic Dialectology: A Survey of Research since 1989

The last 25 years in Slavic dialectology mark the period not only of JSL’s founding but also of major and multiple political, social, and economic reorganizations in predominantly Slavic-speaking states. During this period research institutions and their priorities and projects have both continued and changed; technological innovation has meant moving towards electronic dissemination, “digital humanities,” and innovative modes of presenting research data and findings. In some cases major works (e.g., dialect atlases) have advanced during this period. Moreover, a new generation of scholars has had greater opportunities for mobility and therefore exposure to a variety of linguistic frameworks and approaches, which has fostered cross-border collaboration in the field. The present essay gives an overview of progress made on dialect projects both created institutionally and individually and including both traditional (book, article) and new digital means of dissemination

Nutrient contamination from an agricultural non-point source and its mitigation: A case study of EKU Meadowbrook Farm, Madison County, Kentucky

Non-point sources are now responsible for most nutrient contamination in surface water and groundwater, leading to eutrophication and decreased water quality. Because of fertilizer use and animal husbandry, agricultural areas are prime sources for nutrient contamination. Consequently, it is advisable to mitigate entry of nutrients into watersheds from agricultural runoff and groundwater flow. Eastern Kentucky University (EKU) Meadowbrook Farm (Madison County, Kentucky) seeks to decrease its export of nutrients to Muddy Creek, which is tributary of the Kentucky River. To demonstrate the efficacy of any sequestration strategies, nutrient export must be measured both before and after sequestration efforts are implemented. Over the past two field seasons, we have investigated the sources and behavior of dissolved nutrients (phosphate, PO43-; ammonium, NH4+; nitrate, NO3-) and other dissolved ions, and their transport via hydrologic pathways at the Farm. Here, we present our findings in three parts: (1) background nutrient concentration in surface water and groundwater during fair-weather times and identification of likely nutrient sources (Borowski et al.); (2) details of cation and nutrient drainage from the Farm during rain events (Buskirk et al.); and (3) quantification of nutrient export from a representative sub-watershed on the Farm during a major rainfall event (Winter et al.). Meadowbrook Farm is a working farm raising crops (mainly corn and soybeans), and rearing dairy and beef cattle and other livestock. Livestock produce manure that is eventually applied to pasture and croplands; supplemental fertilizer is also used. These are the primary sources for excess nutrients that leave the Farm via overland and groundwater flow. We sampled water from several different water sources and measured their nutrient content. Water types include that from drainage tiles, springs (groundwater), and surface water within intermittent streams on the Farm, other adjacent streams, and Muddy Creek. Water samples were passed through a 0.4 mm syringe filter and then preserved at a pH of 2 with sulfuric acid (H2SO4). Nutrient concentration, expressed in terms of phosphorus (P) and nitrogen (N) content, was measured colorimetrically using an UV-VIS spectrophotometer and the ascorbic acid (orthophosphate; P-PO43-), sodium hypochlorite (ammonium, N-NH4+), and cadmium reduction (nitrate, N-NO3-) methods. Nitrate is the nutrient contaminant with highest median concentration (~1.1 mg/L N-NO3) in surface waters; median concentration for ammonium and phosphate are ~0.3 mg/L N-NH4+ and ~0.03 mg/L P-PO43-, respectively. Relative to national data, Farm groundwater is enriched in all nutrients with median concentrations of ~0.04 mg/L N-NH4+, ~7.3 mg/L N-NO3, and ~0.04 mg/L P-PO43-. Enrichment in ammonium is more significant compared to that of nitrate and phosphate. These data provide fair-weather, background estimates for comparison to nutrient export that occur during rain events