Fun Anatomy: A Supplemental Website for the Upper Extremity

In accordance with the Accreditation Council for Occupational Therapy Education (ACOTE) standards, the occupational therapy program at the University of Puget Sound requires the completion of an anatomy course as part of the master’s degree curriculum. Currently, the program’s functional anatomy course does not provide any online resources to support students’ mastery of course content. Due to advances in technology, an increasing number of professional degree programs are either web-based or are adding online elements (Donovan, 2008; Friedman, Watts, Croston, & Durkin, 2002; Fallon, 2011). Course-specific online resources have been shown to enhance student learning and performance (Thompson, Ford, & Webster, 2011). A customized supplemental website was created to accompany the functional anatomy course as a learning enhancement. The website includes diagrams, flash cards, quiz questions, case studies, and additional resources. The various elements of the website were developed to address different learning styles and to cycle students through the stages of Kolb’s model of experiential learning (Kolb, 1984; Friedman, Watts, Croston, & Durkin, 2002). The goal of the website is for the user to achieve a 90% standard on the quizzes and case study questions, which is higher than the university graduate school’s 83% (3.0 GPA) requirement to maintain good standing. Use of the website in a pilot study by a sample group of the program’s students resulted in 100% positive recommendation for its use as a resource in the functional anatomy course

Soil O2 controls denitrification rates and N2O yield in a riparian wetland

[1] Wetland soil oxygen (O2) is rarely measured, which limits our understanding of a key regulator of nitrogen loss through denitrification. We asked: (1) How does soil [O2] vary in riparian wetlands? (2) How does this [O2] variation affect denitrification rates and end products? and (3) How does [O2] variation and previous exposure to O2affect trace gas fluxes? We collected a continuous seven-month record of [O2] dynamics in a “wet” and “dry” riparian zone. In April 2009, soil [O2] ranged from 0 to 13% and consistently increased with increasing distance from the stream. [O2] gradually declined in all sensors until all sensors went anoxic in early September 2009. In mid-fall, a dropping water table increased soil [O2] to 15–20% within a 2–3 day period. We measured denitrification using the Nitrogen-Free Air Recirculation Method (N-FARM), a direct measurement of N2 production against a helium background. Denitrification rates were significantly higher in the wetter areas, which correlated to lower O2 conditions. Denitrification rates in the drier areas correlated with [O2] in the early spring and summer, but significantly decreased in late summer despite decreasing O2 concentrations. Increasing [O2] significantly increased core N2O production, and therefore may be an important control on nitrous oxide yield. Field N2O fluxes, however, were highly variable, ranging from 0 to 800 ug N m−2 hr−1 with no differences between the wet and dry sites. Future research should focus on understanding the biotic and abiotic controls on O2 dynamics, and O2 dynamics should be included in models of soil N cycling and trace gas fluxes

Effects of Calcium Treatment on Forest Floor Organic Matter Composition Along an Elevation Gradient

Calcium amendment is a restorative option for nutrient-depleted, acidic soils in the forests of the northeastern United States. We studied the effects of watershed-scale wollastonite (CaSiO3) application on the structural composition of soil organic matter (SOM) and hot-water extractable organic matter (HWEOM) at the Hubbard Brook Experiment Forest in New Hampshire 7-9 years after treatment, along an elevation gradient. Soils in the high-elevation spruce/fir/birch (SFB) zone contained significantly greater amounts of HWEOM compared to lower elevation hardwood soils, likely due to differences in litter quality and slower decomposition rates in colder soils at higher elevation. The only significant difference in hot-water extractable organic carbon (HWEOC) concentration between reference and calcium-treated watersheds was in Oie horizons of the SFB zone, which also exhibited the greatest degree of soil chemical change after treatment. The 13C nuclear magnetic resonance (NMR) spectra showed no significant patterns in O-alkyl C abundance for either soil or HWEOM along the elevation gradient, suggesting that there were no elevation-related patterns in carbohydrate concentration. The general absence of long-term effects in this study suggests that effects of Ca amendment at this dosage on the composition of soil organic matter were small or short-lived

The Eco-Techno Spectrum: Exploring Knowledge Systems\u27 Challenges in Green Infrastructure Management

Infrastructure crises are not only technical problems for engineers to solve—they also present social, ecological, financial, and political challenges. Addressing infrastructure problems thus requires a robust planning process that includes examination of the social and ecological systems supporting infrastructure, alongside technical systems. An integrative Social, Ecological, and Technological Systems (SETS) analysis of infrastructure solutions can complement the planning process by revealing potential trade-offs that are often overlooked in standard procedures. We explore the interconnected SETS of the infrastructure problem in the US through comparative case studies of green infrastructure (GI) development in Portland and Baltimore. Currently a popular infrastructure solution to a wide variety of urban ills, GI is the use and mimicry of ecological components (e.g., plants) to perform municipal services (e.g., stormwater management). We develop the ecological-technological spectrum—or ‘eco-techno spectrum’—as a framing tool to bridge all three SETS dimensions. The eco-techno spectrum becomes a platform to explore the institutional knowledge system dynamics of GI development where social dimensions are organized across ecological and technological aspects of GI, exposing how governance differs across specific forms of ecological and technological hybridity. In this study, we highlight the knowledge system challenges of urban planning institutions as a key consideration in the realization of innovative infrastructure crisis ‘fixes.’ Disconnected definition and measurement of GI emerge as two distinct challenges across the knowledge systems examined. By revealing and discussing these challenges, we can begin to recognize—and better plan for—gaps in municipal planning knowledge systems, promoting decisions that address the roots of infrastructure crises rather than treating only their symptoms

Symptoms of Nitrogen Saturation in a Riparian Wetland

Riparian forests are in a unique position in the landscape since they form a transition between uplands and aquatic systems. These ecosystems may be highly susceptible to nitrogen (N) saturation since they may be subject to high inputs of N from upland areas. We measured potential net N mineralization and nitrification, soil inorganic N levels, microbial biomass carbon (C) and N content, and the N content of litter as indicators of N saturation in two riparian zones on the eastern and western sides of a stream. The sites had similar soils, vegetation, and hydrology, but differing upland land use. The eastern or enriched site was downgradient of a dense residential housing development (built in the 1950s) that produced high groundwater nitrate (NO3—) concentrations. The western or control site had an undeveloped upland. Our objectives were (1) to evaluate if groundwater NO3— loading had induced changes in surface soil N—cycle processes that are symptoms of N saturation in the enriched site and (2) to evaluate these changes in relation to inputs and outputs of N to the site. Soil inorganic—N levels, litter N content, and potential net N mineralization and nitrification were significantly higher on the enriched site relative to the control site, suggesting that the enriched site and N saturated. However, input—output analysis indicated that the enriched site was still a sink for upland derived NO3—. High rates of denitrification and storage of N in soil organic matter appear to moderate N saturation on the enriched site

Denitrification and nitrous oxide emissions from riparian forests soils exposed to prolonged nitrogen runoff

Compared to upland forests, riparian forest soils have greater potential to remove nitrate (NO3) from agricultural run-off through denitrification. It is unclear, however, whether prolonged exposure of riparian soils to nitrogen (N) loading will affect the rate of denitrification and its end products. This research assesses the rate of denitrification and nitrous oxide (N2O) emissions from riparian forest soils exposed to prolonged nutrient run-off from plant nurseries and compares these to similar forest soils not exposed to nutrient run-off. Nursery run-off also contains high levels of phosphate (PO4). Since there are conflicting reports on the impact of PO4 on the activity of denitrifying microbes, the impact of PO4 on such activity was also investigated. Bulk and intact soil cores were collected from N-exposed and non-exposed forests to determine denitrification and N2O emission rates, whereas denitrification potential was determined using soil slurries. Compared to the non-amended treatment, denitrification rate increased 2.7- and 3.4-fold when soil cores collected from both N-exposed and non-exposed sites were amended with 30 and 60 μg NO3-N g-1 soil, respectively. Net N2O emissions were 1.5 and 1.7 times higher from the N-exposed sites compared to the non-exposed sites at 30 and 60 μg NO3-N g-1 soil amendment rates, respectively. Similarly, denitrification potential increased 17 times in response to addition of 15 μg NO3-N g-1 in soil slurries. The addition of PO4 (5 μg PO4–P g-1) to soil slurries and intact cores did not affect denitrification rates. These observations suggest that prolonged N loading did not affect the denitrification potential of the riparian forest soils; however, it did result in higher N2O emissions compared to emission rates from non-exposed forests

Plant Trait Diversity Buffers Variability in Denitrification Potential over Changes in Season and Soil Conditions

BACKGROUND: Denitrification is an important ecosystem service that removes nitrogen (N) from N-polluted watersheds, buffering soil, stream, and river water quality from excess N by returning N to the atmosphere before it reaches lakes or oceans and leads to eutrophication. The denitrification enzyme activity (DEA) assay is widely used for measuring denitrification potential. Because DEA is a function of enzyme levels in soils, most ecologists studying denitrification have assumed that DEA is less sensitive to ambient levels of nitrate (NO(3)(-)) and soil carbon and thus, less variable over time than field measurements. In addition, plant diversity has been shown to have strong effects on microbial communities and belowground processes and could potentially alter the functional capacity of denitrifiers. Here, we examined three questions: (1) Does DEA vary through the growing season? (2) If so, can we predict DEA variability with environmental variables? (3) Does plant functional diversity affect DEA variability? METHODOLOGY/PRINCIPAL FINDINGS: The study site is a restored wetland in North Carolina, US with native wetland herbs planted in monocultures or mixes of four or eight species. We found that denitrification potentials for soils collected in July 2006 were significantly greater than for soils collected in May and late August 2006 (p<0.0001). Similarly, microbial biomass standardized DEA rates were significantly greater in July than May and August (p<0.0001). Of the soil variables measured--soil moisture, organic matter, total inorganic nitrogen, and microbial biomass--none consistently explained the pattern observed in DEA through time. There was no significant relationship between DEA and plant species richness or functional diversity. However, the seasonal variance in microbial biomass standardized DEA rates was significantly inversely related to plant species functional diversity (p<0.01). CONCLUSIONS/SIGNIFICANCE: These findings suggest that higher plant functional diversity may support a more constant level of DEA through time, buffering the ecosystem from changes in season and soil conditions

Long-Term Integrated Studies Show Complex and Surprising Effects of Climate Change in the Northern Hardwood Forest

Evaluations of the local effects of global change are often confounded by the interactions of natural and anthropogenic factors that overshadow the effects of climate changes on ecosystems. Long-term watershed and natural elevation gradient studies at the Hubbard Brook Experimental Forest and in the surrounding region show surprising results demonstrating the effects of climate change on hydrologic variables (e.g., evapotranspiration, streamflow, soil moisture); the importance of changes in phenology on water, carbon, and nitrogen fluxes during critical seasonal transition periods; winter climate change effects on plant and animal community composition and ecosystem services; and the effects of anthropogenic disturbances and land-use history on plant community composition. These studies highlight the value of long-term integrated research for assessments of the subtle effects of changing climate on complex ecosystems

Beaver Ponds: Resurgent Nitrogen Sinks for Rural Watersheds in the Northeastern United States

Beaver-created ponds and dams, on the rise in the northeastern United States, reshape headwater stream networks from extensive, free-flowing reaches to complexes of ponds, wetlands, and connecting streams. We examined seasonal and annual rates of nitrate transformations in three beaver ponds in Rhode Island under enriched nitrate-nitrogen (N) conditions through the use of 15N mass balance techniques on soil core mesocosm incubations. We recovered approximately 93% of the nitrate N from our mesocosm incubations. Of the added nitrate N, 22 to 39% was transformed during the course of the incubation. Denitrification had the highest rates of transformation (97–236 mg N m−2 d−1), followed by assimilation into the organic soil N pool (41–93 mg N m−2 d−1) and ammonium generation (11–14 mg N m−2 d−1). Our denitrification rates exceeded those in several studies of freshwater ponds and wetlands; however, rates in those ecosystems may have been limited by low concentrations of nitrate. Assuming a density of 0.7 beaver ponds km−2 of catchment area, we estimated that in nitrate-enriched watersheds, beaver pond denitrification can remove approximately 50 to 450 kg nitrate N km−2 catchment area. In rural watersheds of southern New England with high N loading (i.e., 1000 kg km−2), denitrification from beaver ponds may remove 5 to 45% of watershed nitrate N loading. Beaver ponds represent a relatively new and substantial sink for watershed N if current beaver populations persist