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Inductive Measurement Of Optically Hyperpolarized Phosphorous Donor Nuclei In An Isotopically Enriched Silicon-28 Crystal, P. Gumann, O. Patange, C. Ramanathan, H. Haas

Dartmouth Scholarship

We experimentally demonstrate the first inductive readout of optically hyperpolarized phosphorus-31 donor nuclear spins in an isotopically enriched silicon-28 crystal. The concentration of phosphorus donors in the crystal was 1.5×1015  cm−3, 3 orders of magnitude lower than has previously been detected via direct inductive detection. The signal-to-noise ratio measured in a single free induction decay from a 1  cm3 sample (≈1015 spins) was 113. By transferring the sample to an X-band ESR spectrometer, we were able to obtain a lower bound for the nuclear spin polarization at 1.7 K of ∼64%. The 31P-T2 measured with a Hahn echo sequence was …

Single- And Dual-Porosity Calibration And Long-Term Modeling Of Highly Conductive Floodplain Soils In The Ozark Ecoregion, Ryan P. Freiberger

Department of Biological Systems Engineering: Dissertations and Theses

Phosphorus (P) is a critical nutrient for agriculture, but is also responsible for surface water enrichment that leads to algal growth. While P loading to surface waters has traditionally been thought to occur from surface runoff, contributions from subsurface transport can also be significant. Subsurface transport through gravelly soils in the Ozark ecoregion can have a significant, yet poorly-documented effect on P movement to groundwater.

Long-term P modeling was performed in HYDRUS-1D and 2D using data collected from short-term plot experiments featuring gravelly soils. Seven model levels were developed to illustrate a wide variety of laboratory and field conditions. Calibration …

Redox Chemistry In The Phosphorus Biogeochemical Cycle, Matthew A. Pasek, Jacqueline M. Sampson, Zachary Atlas

School of Geosciences Faculty and Staff Publications

The element phosphorus (P) controls growth in many ecosystems as the limiting nutrient, where it is broadly considered to reside as pentavalent P in phosphate minerals and organic esters. Exceptions to pentavalent P include phosphine—PH₃—a trace atmospheric gas, and phosphite and hypophosphite, P anions that have been detected recently in lightning strikes, eutrophic lakes, geothermal springs, and termite hindguts. Reduced oxidation state P compounds include the phosphonates, characterized by C−P bonds, which bear up to 25% of total organic dissolved phosphorus. Reduced P compounds have been considered to be rare; however, the microbial ability to use reduced P …

Jackson Lake Limnology, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

The limnology of Jackson Lake has been studied very little, despite the fact that it is the uppermost large lake on the headwaters of the Snake River, one of the larger rivers in the country (Hayden 1969). It is also an important fishery, largely for introduced lake trout. In 2014 we took our incoming graduate students to the Jackson Hole and one part of this introductory course focused on the limnology of the lake. Prior to the arrival of the students, a nutrient addition bioassay was initiated to demonstrate an experimental approach to understanding what nutrients might control production processes …

Effects Of Calcium Silicate Treatment On The Composition Of Forest Floor Organic Matter In A Northern Hardwood Forest Stand, Ankit Balaria, Chris E. Johnson, Peter M. Groffman, Melany C. Fisk

Civil and Environmental Engineering

Calcium amendment can help improve forest sustainability in stands that have been impacted by chronic acid deposition. An important component of this improvement is the stimulation of the microbial activity that supports ecosystem nutrient cycling processes. To test the hypothesis that Ca treatment alters the structure and solubility of organic matter substrates, an important driver of microbial activity, we investigated the effect of wollastonite (CaSiO₃) treatment on soil organic matter (SOM) and hot-water-extractable organic matter (HWEOM). We found a decrease in the HWEOM content of forest floor soils within two years of treatment with a high dosage of …

Approaches For Studying Fish Production: Do River And Lake Researchers Have Different Perspectives? – Extended Abstract, Wayne A. Wurtsbaugh, Nicholas A. Heredia, Brian G. Laub, Christy S. Meredith, Harrison E. Mohn, Sarah E. Null, David A. Pluth, Brett B. Roper, W. Carl Saunders, David King Stevens, Richard H. Walker, Kit Wheeler

Watershed Sciences Faculty Publications

Biased perspectives of fisheries researchers may hinder scientific progress and effective management if limiting factors controlling productivity go unrecognized. We investigated whether river and lake researchers used different approaches when studying salmonid production and whether any differences were ecologically supported. We assessed 564 peer‐reviewed papers published between 1966 and 2012 that studied salmonid production or surrogate variables (e.g., abundance, growth, biomass, population) and classified them into five major predictor variable categories: physical habitat, fertility (i.e., nutrients, bottom‐up), biotic, temperature, and pollution. The review demonstrated that river researchers primarily analyzed physical habitat (65% of studies) and lake researchers primarily analyzed fertility …

Height And Clonality Traits Determine Plant Community Responses To Fertilization, Timothy L. Dickson, Gary G. Mittelbach, Heather L. Reynolds, Katherine L. Gross

Biology Faculty Publications

Fertilization via agricultural inputs and nutrient deposition is one of the major threats to global terrestrial plant richness, yet we still do not fully understand the mechanisms by which fertilization decreases plant richness. Tall clonal species have recently been proposed to cause declines in plant species richness by increasing in abundance in response to fertilization and competing strongly with other species. We tested this hypothesis in a fertilization experiment in a low productivity grassland by using a novel experimental manipulation of the presence vs. absence of clonal species and by examining the role of height within these treatments. We found …

Phosphorous Acid Route Synthesis Of Iron Tavorite Phases, Lifepo₄(Oh)ₓf₁₋ₓ [0 ≤ X ≤ 1] And Comparative Study Of Their Electrochemical Activities, Hooman Yaghoobnejad Asl, Amitava Choudhury

Chemistry Faculty Research & Creative Works

New synthesis routes were employed for the synthesis of three derivatives of iron hydroxo-, fluoro-, and mixed hydroxo-fluoro phosphates LiFePO ₄(OH)_xF_1-x where 0 ? x ? 1 with the tavorite structure type, and their detail electrochemical activities have been presented. The hydrothermal synthesis of the pure hydroxo-derivative, LiFePO₄OH, using phosphorous acid as a source of phosphate yielded good quality crystals from which the crystal structure was solved for the first time using SC-XRD (single crystal X-ray diffraction). The fluoro derivative, LiFePO₄F, was prepared as a very fine powder at low temperature in …

Finite Element Modeling Of Long-Term Phosphorus Leaching Through Macropores In The Ozark Ecoregion, Ryan P. Freiberger, Derek M. Heeren, Garey A. Fox, Chad J. Penn, Dean E. Eisenhauer

Department of Biological Systems Engineering: Papers and Publications

Phosphorus (P) is a critical nutrient for plant growth in agriculture, but is also responsible for surface water enrichment that leads to toxic algal growth. While P loading to surface waters has traditionally been thought to occur from surface runoff, contributions from subsurface transport can also be significant. While P transport through many soil types is well-documented, the presence of highly conductive gravel outcrops and macropore networks can have a significant, yet poorly-documented effect on P movement to the aquifer. Floodplain soils in the Ozark ecoregion generally contain coarse chert gravel layers that exhibit macropore behavior. Previous research has evaluated …

Simulating Everglades National Park Hydrology And Phosphorus Transport Under Existing And Future Scenarios Using Numerical Modeling, Stephanie Long

FIU Electronic Theses and Dissertations

The Florida Everglades has a long history of anthropogenic changes which have impacted the quantity and quality of water entering the system. Since the construction of Tamiami Trail in the 1920's, overland flow to the Florida Everglades has decreased significantly, impacting ecosystems from the wetlands to the estuary. The MIKE Marsh Model of Everglades National Park (M3ENP) is a numerical model, which simulates Everglades National Park (ENP) hydrology using MIKE SHE/MIKE 11software. This model has been developed to determine the parameters that effect Everglades hydrology and understand the impact of specific flow changes on the hydrology of the system.

As …

Dissolved And Particulate Nutrient Transport Dynamics Of A Small Irish Catchment: The River Owenabue, S. T. Harrington, Joseph R. Harrington

Publications

The objective of this research was to investigate the relationship between water and sediment discharge on the transport of nutrients: nitrogen and phosphorus. Water discharge, suspended sediment concentration and dissolved and particulate forms of nitrogen and phosphorus were monitored on the 105 km2 River Owenabue catchment in Ireland. Water discharge was found to have an influence on both particulate and dissolved nutrient transport, but more so for particulate nutrients. The particulate portion of N and P in collected samples was found to be 24 and 39 %, respectively. Increased particulate nitrogen concentrations were found at the onset of high discharge …

P‐Nexfs Analysis Of Aerosol Phosphorus Delivered To The Mediterranean Sea, Amelia F. Longo, Ellery D. Ingall, Julia M. Diaz, Michelle Oakes, Laura E. King, Athanasios Nenes, Nikolaos Mihalopoulos, Kaliopi Violaki, Anna Avila, Claudia R. Benitez-Nelson, Jay Brandes, Ian Mcnulty, David J. Vine

Faculty Publications

Biological productivity in many ocean regions is controlled by the availability of the nutrient phosphorus. In the Mediterranean Sea, aerosol deposition is a key source of phosphorus and understanding its composition is critical for determining its potential bioavailability. Aerosol phosphorus was investigated in European and North African air masses using phosphorus near‐edge X‐ray fluorescence spectroscopy (P‐NEXFS). These air masses are the main source of aerosol deposition to the Mediterranean Sea. We show that European aerosols are a significant source of soluble phosphorus to the Mediterranean Sea. European aerosols deliver on average 3.5 times more soluble phosphorus than North African aerosols …

Effect Of Water Management On Interannual Variation In Bulk Soil Properties From The Eastern Coastal Everglades, R. M. Chambers, R. L. Hatch, T. M. Russell

FCE LTER Journal Articles

We examined interannual variation in soil properties from wetlands occurring in adjacent drainage basins from the southeastern Everglades. Triplicate 10-cm soil cores were collected, homogenized, and analyzed during the wet season 2006–2010 from five freshwater sawgrass wetland marshes and three estuarine mangrove forests. Soil bulk density from the Taylor Slough basin ranged from 0.15 gm-cm⁻³ to 0.5 gm-cm⁻³, was higher than from the Panhandle basin every year, and generally increased throughout the study period. Organic matter as a percent loss on ignition ranged from 7 % to 12 % from freshwater marshes and from 13 % to …

Relating Freshwater Flow With Estuarine Water Quality In The Southern Everglades Mangrove Ecotone, Henry O. Briceño, Gabriel Miller, Stephen E. Davis Iii

FCE LTER Journal Articles

Florida Bay is more saline than it was historically, and reduced freshwater flows may lead to more phosphorus inputs to the mangrove ecotone from the marine end-member. This is important given plans to restore freshwater flow into eastern Florida Bay. We investigated the relationships between salinity, nutrients, and hydrologic variables in the mangrove ecotone of Taylor Slough. We expected that total phosphorus (TP) would increase with salinity, reflecting a downstream marine source, while total nitrogen (TN) would increase with flow in the mangrove ecotone. Despite expectations of increased flows improving the ecological health of lower Taylor Slough and Florida Bay, …

Dust Mediated Transfer Of Phosphorus To Alpine Lake Ecosystems Of The Wind River Range, Wyoming, Usa, Janice Brahney, Ashley P. Ballantyne, P. Kociolek, Sarah A. Spaulding, Megan Otu, T. Porwoll, Jason C. Neff

Watershed Sciences Faculty Publications

Alpine lakes receive a large fraction of their nutrients from atmospheric sources and are consequently sensitive to variations in both the amount and chemistry of atmospheric deposition. In this study we explored the spatial changes in lake water chemistry and biology along a gradient of dust deposition in the Wind River Range, Wyoming. Regional differences were explored using the variation in bulk deposition, lake water, sediment, and bedrock geochemistry and catchment characteristics. Dust deposition rates in the Southwestern region averaged 3.34 g m−2 year−1, approximately three times higher than deposition rates in the Northwestern region (average 1.06 g m−2 year−1). …

Assessing Nutrient Limitation In Complex Forested Ecosystems : Alternatives To Large-Scale Fertilization Experiments, Benjamin W. Sullivan, Silvia Alvarez-Clare, Sarah C. Castle, Stephen Porder, Sasha C. Reed, Laura Schreeg, Cory C. Cleveland, Alan R. Townsend

Ecosystem and Conservation Sciences Faculty Publications

Quantifying nutrient limitation of primary productivity is a fundamental task of terrestrial ecosystem ecology, but in a high carbon dioxide environment it is even more critical that we understand potential nutrient constraints on plant growth. Ecologists often manipulate nutrients with fertilizer to assess nutrient limitation, yet for a variety of reasons, nutrient fertilization experiments are either impractical or incapable of resolving ecosystem responses to some global changes. The challenges of conducting large, in situ fertilization experiments are magnified in forests, especially the high-diversity forests common throughout the lowland tropics. A number of methods, including fertilization experiments, could be seen as …

Sevilleta Lter Vegetation Sample Catalog- Ground Samples For Chemical Analysis (2000-Present), Douglas I. Moore, Stephanie Baker

Sevilleta LTER Program Data

Several long-term studies at the Sevilleta LTER measure net primary production (NPP) across ecosystems and treatments. Net primary production is a fundamental ecological variable that quantifies rates of carbon consumption and fixation. Estimates of NPP are important in understanding energy flow at a community level as well as spatial and temporal responses to a range of ecological processes. The NPP weight data (SEV 157) is obtained by harvesting a series of covers for species observed during plot sampling. These species are always harvested from habitat comparable to the plots in which they were recorded. This data is then used to …

Is There Light After Depth? Distribution Of Periphyton Chlorophyll And Productivity In Lake Littoral Zones, Yvonne Vadeboncoeur, Shawn P. Devlin, Peter B. Mcintyre, M. J. Vander Zanden

Biological Sciences Faculty Publications

Periphyton and phytoplankton contribute to the base of lake food webs, and both groups of microalgae are influenced by resources and physical forcing. Spatial variation in light availability interacts with the physical dynamics of the water column to create predictable depth gradients in resources and disturbance that may differentially affect periphyton vs phytoplankton. We characterized the depth distribution of chlorophyll and productivity of periphyton on sediments (epipelon) and phytoplankton in the euphotic zones of 13 oligomesotrophic lakes that span a large size gradient (0.017–32,600 km²). Epipelic chlorophyll usually increased with depth in the epilimnion. Light was the primary …

Phosphorus Requirements Of Some Selected Soil Types In The Fiji Sugarcane Belt, M S. Goundar, R John Morrison, C Togamana

Faculty of Science, Medicine and Health - Papers: part A

The availability of phosphorus (P) in soil is perceived to be one of the limiting factors to sustainable sugarcane production in Fiji. The main objective of this research was to ascertain the amount of bioavailable phosphorus in some Fiji sugarcane growing area soils; this will be valuable in improving the determination of the required amount of inorganic fertilizer to be applied to the soil. In this study, twelve different soils were selected from the sugarcane belt of Fiji and phosphorus buffer index (PBI) and phosphorus isotherm experiments were performed. Soil physical and chemical parameters were also measured and Pearson's correlation …

Phosphorus Speciation And Changes With Depth In The Sediment Of Lake Illawarra, New South Wales, Australia, Changyou Wang, R John Morrison

Faculty of Science, Medicine and Health - Papers: part A

In order to better understand phosphorus (P) cycling and origins in the sediment of the Lake Illawarra, two sediment cores were extracted in November, 2010 and a modified sequential extraction scheme (SEDEX) was used to profile the exchangeable P (Pex), reactive Fe/Al-bound P (Preac), reductive Fe/Al-bound P (Predu), authigenic apatite P (Pauth), detrital P (Pdet), organic P (Porg) and residual P (Presi). The total sedimentary P (TP) ranged from 93 to 437 μg g−1, and was dominated by inorganic P. The average percentage of each fraction of P in the sediment followed the sequence: Preac (28.6 %) > Presi (23.5 %) …

Toward Resource Recovery From Wastewater: Phosphorus Extraction From Digested Sludge Using Hybrid Forward Osmosis - Membrane Distillation Process, Ming Xie, Long D. Nghiem, William E. Price, Menachem Elimelech

Faculty of Engineering and Information Sciences - Papers: Part A

We demonstrate the simultaneous extraction of phosphorus and clean water from digested sludge centrate using a forward osmosis (FO)−membrane distillation (MD) hybrid process. In this FO−MD hybrid process, FO concentrates orthophosphate and ammonium for subsequent phosphorus recovery in the form of struvite (MgNH4PO4·6H2O), while MD is used to recover the draw solution and extract clean water from the digested sludge centrate. A decline in water flux was observed during the FO process, but fouling was largely reversible after a brief, simple membrane flushing using deionized water. The FO process also provides an effective pretreatment capacity to the subsequent MD process, …

Nutrient Concentrations Of Runoff As Affected By The Diameter Of Unconsolidated Material From Feedlot Surfaces, John E. Gilley, Gregory Boone, David B. Marx

Department of Biological Systems Engineering: Papers and Publications

Beef cattle feedlots contain unconsolidated material that accumulates on the feedlot surface during a feeding cycle. This study was conducted to measure the effects of varying diameters of unconsolidated surface material and varying flow rates on nutrient concentrations in runoff. Unconsolidated surface material with an average diameter of 4.76, 9.53, 19.1, or 47.5 mm and a composite sample with a 15.2 mm mean diameter were placed within 0.75 m wide × 4.0 m long plot areas. Flow was then introduced at the top of the plots in successive increments, and runoff samples for water quality analyses were obtained. Particle diameter …