Iron (Oxyhydr)Oxides Serve as Phosphate Traps in Tundra and Boreal Peat Soils
Abstract not provided
Herndon, Elizabeth M.↗
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CONFIRMATION OF CIRCUMSTELLAR PHOSPHINE
Phosphine (PH{sub 3}) was tentatively identified a few years ago in the carbon star envelopes IRC +10216 and CRL 2688 from observations of an emission line at 266.9 GHz attributable to the J = 1-0 rotational transition. We report the detection of the J = 2-1 rotational transition of PH{sub 3} in IRC +10216 using the HIFI instrument on board Herschel, which definitively confirms the identification of PH{sub 3}. Radiative transfer calculations indicate that infrared pumping in excited vibrational states plays an important role in the excitation of PH{sub 3} in the envelope of IRC +10216, and that the observed lines are consistent with phosphine being formed anywhere between the star and 100 R {sub *} from the star, with an abundance of 10{sup –8} relative to H{sub 2}. The detection of PH{sub 3} challenges chemical models, none of which offer a satisfactory formation scenario. Although PH{sub 3} holds just 2% of the total available phosphorus in IRC +10216, it is, together with HCP, one of the major gas phase carriers of phosphorus in the inner circumstellar layers, suggesting that it could also be an important phosphorus species in other astronomical environments. This is the first unambiguous detection of PH{sub 3} outside the solar system, and is a further step toward a better understanding of the chemistry of phosphorus in space.
79 ASTRONOMY AND ASTROPHYSICS↗
Soil properties and root characteristics across four lowland Panamanian forests from 0 - 1 m soil depths
Objectives:Fine roots significantly influence ecosystem-scale cycling of nutrients, carbon (C), and water, yet there is limited understanding of how fine root traits vary across and within tropical forests, some of Earth's most C-rich ecosystems. The biomass of fine roots can impact soil carbon storage, as root mortality is a primary source of new carbon to soils. A positive relationship has been observed between fine root biomass and soil carbon stocks in Panama (Cusack et al 2018). Beyond biomass, root characteristics like specific root length (SRL) could also influence soil carbon, as roots with higher SRL are less dense and thinner, potentially decomposing more easily or promoting soil aggregation. Understanding the effects of root morphology and tissue quality on soil carbon storage and with soil properties in general can improve predictions of landscape-scale carbon patterns. We aggregated new data of root biomass, morphology and nutrient content at 0-10 cm, 10-20 cm, 20-50 cm and 50-100 cm depth increments across four distinct lowland Panamanian forests and paired with already published datasets (Cusack et al 2018; Cusack and Turner 2020) of soil chemistry from the same sites and soil depths to explore relationship between soil carbon stocks and root characteristics.Datasets included:The datasets provided include .csv and .xlsx files for fine root characteristics and soil chemistry from four different forests across 0-10 cm, 10-20 cm, 20-50 cm, and 50-100 cm depth increments. Root characteristics include live fine root biomass, dead fine root biomass, coarse root biomass, specific root length, root diameter, root tissue density, specific root area, root %N, root %C, and root C/N ratio. Soil chemistry data includes total carbon (TC), dissolved organic carbon (DOC), bulk density, total phosphorus (TP), available phosphorus (AEM Pi), and various Mehlich-extractable elements such as aluminum, calcium, iron, potassium, manganese, phosphorus, and zinc. Nitrogen content measures include ammonium, nitrate, total dissolved nitrogen (TDN), dissolved inorganic nitrogen (DIN), and dissolved organic nitrogen (DON). The dataset also includes total exchangeable bases (TEB) and effective cation exchange capacity (ECEC) in both centimoles of charge per kilogram and micromoles of charge per gram. The soil chemistry data was obtained from Cusack et al (2018) and Cusack and Turner (2020) and paired with root characteristics data for the same depth increments and sites. Additionally, a .kml file is provided with coordinates for all 32 plots included in the study across four forests (n = 8 plots per site). Root data was averaged across these 8 plots per site and soil data was collected in one pit in each site. This dataset serves as baseline data before a throughfall exclusion experiment, Panama Rainforest Changes with Experimental Drying (PARCHED), was implemented. No special software is needed to open these files.
54 ENVIRONMENTAL SCIENCES↗
NIST: Soil Respiration, Moisture, Temperature, Chemistry; and Fine Root Measurements from a Transect Through a Forest Edge, Gaithersburg, Maryland, 2017-2021
This dataset contains soil respiration, moisture, temperature, and chemistry, as well as fine root measurements from the National Institute of Standards and Technology (NIST) Forested Optical Reference for Evaluating Sensor Technology (FOREST) research facility at Gaithersburg, Maryland. Measurements were taken at an existing transect array that begins in a grassy meadow, crosses a sharp forest edge, then a small stream, and finally extends upwards in the interior of the forest at the top of a ridge. There are 6 different landscape positions replicated across three transects in the array. Soil respiration was measured during growing seasons in 2017-2019 (2017-06-02 to 2020-02-27). Pedons (1 m3) were isolated from surrounding tree roots using trenching and a fabric to inhibit root ingrowth. Flux measurements inside the pedons were thus assumed to represent heterotrophic only respiration in 2019, and these fluxes were paired with nearby fluxes assumed to represent total respiration. Deep vertical probes measured volumetric moisture content and temperature at the same points in the array every 10 cm in depth to either 90 cm or 120 cm total depth, at 15 minute intervals, from 2019-2021 (2019-07-09 to 2021-09-10). Soil core samples were collected from each of the array points for three different months in early- to mid-2019 (2019-03-19 to 2019-07-10), at three depths each. Soils were analyzed for gravimetric moisture content; pH; total carbon, nitrogen, and phosphorus; texture; microbial biomass carbon, nitrogen, and phosphorus; extractable dissolved organic carbon, nitrogen, and phosphorus; extractable nitrate and ammonia; and extracellular hydrolytic enzyme activities. The fine roots were separated from the cores and segregated by plant functional type (grass or tree species) and if they were dead or alive. Fine roots were then measured for length, surface area, diameter, and dry mass. This dataset contains four data files in comma separated (*.csv) format. These data serve to deepen our understanding of root and soil processes at forest edges and in transitional zones.
54 ENVIRONMENTAL SCIENCES↗
The Fertilizing Role of African Dust in the Amazon Rainforest. A First Multiyear Assessment Based on Data from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations
The productivity of the Amazon rainforest is constrained by the availability of nutrients, in particular phosphorus (P). Deposition of long-range transported African dust is recognized as a potentially important but poorly quantified source of phosphorus. This study provides a first multiyear satellite-based estimate of dust deposition into the Amazon Basin using three dimensional (3D) aerosol measurements over 2007-2013 from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). The 7-year average of dust deposition into the Amazon Basin is estimated to be 28 (8~48) Tg a -1 or 29 (8~50) kg ha -1 a -1 . The dust deposition shows significant interannual variation that is negatively correlated with the prior-year rainfall in the Sahel. The CALIOP-based multi-year mean estimate of dust deposition matches better with estimates from in-situ measurements and model simulations than a previous satellite-based estimate does. The closer agreement benefits from a more realistic geographic definition of the Amazon Basin and inclusion of meridional dust transport calculation in addition to the 3D nature of CALIOP aerosol measurements. The imported dust could provide about 0.022 (0.006~0.037) Tg P of phosphorus per year, equivalent to 23 (7~39) g P ha -1 a -1 to fertilize the Amazon rainforest. This out-of-Basin P input is comparable to the hydrological loss of P from the Basin, suggesting an important role of African dust in preventing phosphorus depletion on time scales of decades to centuries.
54 ENVIRONMENTAL SCIENCES↗
Functionalization of Carbon Monoxide and tert ‐Butyl Nitrile by Intramolecular Proton Transfer in a Bis(Phosphido) Thorium Complex
Abstract We report intramolecular proton transfer reactions to functionalize carbon monoxide and tert ‐butyl nitrile from a bis(phosphido) thorium complex. The reaction of (C 5 Me 5 ) 2 Th[PH(Mes)] 2 , Mes=2,4,6‐Me 3 C 6 H 2 , with 1 atm of CO yields (C 5 Me 5 ) 2 Th( κ 2 ‐(O,O)‐OCH 2 PMes‐C(O)PMes), in which one CO molecule is inserted into each thorium–phosphorus bond. Concomitant transfer of two protons, formerly coordinated to phosphorus, are now bound to one of the carbon atoms from one of the inserted CO molecules. DFT calculations were employed to determine the lowest energy pathway. With tert ‐butyl nitrile, t BuCN, only one nitrile inserts into a thorium–phosphorus bond, but the proton is transferred to nitrogen with one phosphido remaining unperturbed affording (C 5 Me 5 ) 2 Th[PH(Mes)][ κ 2 ‐(P,N)‐N(H)C(CMe 3 )P(Mes)]. Surprisingly, reaction of this compound with KN(SiMe 3 ) 2 removes the proton bound to nitrogen, not phosphorus.
Vilanova, Sean P.↗
Environmental and cost benefits of multi‐purpose buffers in an agricultural watershed for biomass production
Abstract The cost‐benefit of riparian buffers to landowners has not been fully understood despite its ecosystem benefits. This study investigates the environmental and economic value of multi‐purpose buffers for biomass production under alternative land‐management scenarios at the watershed scale. The work incorporates the Soil and Water Assessment Tool with a field‐scale tool, the Agriculture Conservation Practice Framework, and cost‐benefit analysis. Our work took place in the agriculturally dominant Raccoon River watershed (RRW) in Iowa. The cost analysis includes implementing and harvesting the switchgrass buffers, the value of nitrogen and phosphorus fertilizer, and the forgone income of cropland to determine the net return under 12 alternative feedstock scenarios. We estimated that 14 603 Mg of nitrogen and 2563 Mg of phosphorus runoffs can be intercepted by riparian buffers in the RRW, representing a nutrient loss reduction of 11% of nitrogen and 26% of phosphorus. These nutrients are valued at $1.31 million (M) for phosphorus and $1.24 M for nitrogen as fertilizers. The trapped nutrients account for 12% of the riparian buffers’ total cost. We found that net economic returns increase with biomass market price, increase with maintenance fertilizer application, and decrease with the cropland areas that are converted to buffers. Under current land management, a biomass market price at $60 per dry ton of biomass would be economically viable at the sub‐basin level when maintenance fertilizers are applied. At $80 per dry ton, all 108 sub‐basins in the RRW would be profitable up to $517 a year. The results highlight the trade‐offs between water quality and profitability. Published 2021. This article is a U.S. Government work and is inthe public domain in the USA. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.
09 BIOMASS FUELS↗
Improving the SWAT forest module for enhancing water resource projections: A case study in the St. Croix River basin
Abstract Insufficiently calibrated forest parameters of the Soil & Water Assessment Tool (SWAT) may introduce uncertainties to water resource projections in forested watersheds. In this study, we improved SWAT forest parameterization and phosphorus cycling representations to better simulate forest ecosystems in the St. Croix River basin, and we further examined how those improvements affected model projections of streamflow, sediment, and nitrogen export under future climate conditions. Simulations with improved forest parameters substantially reduced model estimates of water, sediment, and nitrogen fluxes relative to those based on default parameters. Differences between improved and default projections can be attributed to the enhanced representation of forest water consumption, nutrient uptake, and protection of soil from erosion. Better representation of forest ecosystems in SWAT contributes to constraining uncertainties in water resource projections. Results of this study highlight the importance of improving SWAT forest ecosystem representations in projecting delivery of water, sediment, and nutrients from land to rivers in response to climate change, particularly for watersheds with large areas of forests. Improved forest parameters and the phosphorus weathering algorithms developed in this study are expected to help enhance future applications of SWAT to investigate hydrological and biogeochemical consequences of climate change.
Yang, Qichun↗
Quantity and quality of water percolating below the root zone of three biofuel feedstock crop systems
Biofuel demand is on the rise, yet there is limited information available about the likely implications of increased planting of cellulosic biofuel crops on water and nutrient fluxes. To help address this gap, this study quantifies subsurface water, nitrate, and dissolved phosphorus fluxes below feedstock crops managed for biofuel production on naturally well drained soils in southern Wisconsin. Automated equilibrium tension lysimeters were used to measure subsurface (below root zone) fluxes of water and nutrients below continuous corn (CC), monoculture switchgrass (SG), and hybrid poplar (HP) cropping systems for three years. Average water fluxes below SG were nearly double those below CC and HP. Most of this difference can be linked to seasonal events, particularly during late winter and early spring when subsurface water fluxes and increased soil moisture were observed below SG plots, likely due to enhanced macropore flow. Nitrate fluxes were approximately 14 times higher below CC than the 37.4 kg NO 3 -N/ha three year annual average observed for SG; the nitrate fluxes were negligible below HP despite similar nitrogen application rates. The high flux in one of the two CC plots is likely due to excessive manure applications prior to the study period; however, the nitrate loss potential from CC is much higher than the perennial crops. Dissolved reactive phosphorus (DRP) concentrations were very low below all three cropping systems (average of 0.076, 0.083, 0.034 mg/L in SG, CC, and HP respectively). For the cropping systems evaluated, nitrate fluxes were driven by concentration differences in leachate and not influenced by nominal differences in N fertilizer inputs, whereas DRP fluxes were mainly driven by water fluxes and therefore independent of phosphorus inputs and soil test phosphorus. The data in this paper provide a foundation to better understand differences in fluxes below different biofuel cropping systems.
54 ENVIRONMENTAL SCIENCES↗
Morphotype-resolved characterization of microalgal communities in a nutrient recovery process with ARTiMiS flow imaging microscopy
Microalgae-driven nutrient recovery represents a promising technology for phosphorus removal from wastewater while simultaneously generating biomass that can be valorized to offset treatment costs. As full-scale processes come online, system parameters including biomass composition must be carefully monitored to optimize performance and prevent culture crashes. In this study, flow imaging microscopy (FIM) was leveraged to characterize microalgal community composition in near real-time at a full-scale municipal wastewater treatment plant (WWTP) in Wisconsin, USA, and population and morphotype dynamics were examined to identify relationships between water chemistry, biomass composition, and system performance. Two FIM technologies, FlowCam and ARTiMiS, were evaluated as monitoring tools. ARTiMiS provided a more accurate estimate of total system biomass, and estimates derived from particle area as a proxy for biovolume yielded better approximations than particle counts. Deep learning classification models trained on annotated image libraries demonstrated equivalent performance between FlowCam and ARTiMiS, and convolutional neural network (CNN) classifiers proved significantly more accurate when compared to feature table-based dense neural network (DNN) models. Across a two-year study period, Scenedesmus spp. appeared most important for phosphorus removal, and were negatively impacted by elevated temperatures and increase in nitrite/nitrate concentrations. Chlorella and Monoraphidium also played an important role in phosphorus removal. For both Scenedesmus and Chlorella, smaller morphological types were more often associated with better system performance, whereas larger morphotypes likely associated with stress response(s) correlated with poor phosphorus recovery rates. Furthermore, these results demonstrate the potential of FIM as a critical technology for high-resolution characterization of industrial microalgal processes.
59 BASIC BIOLOGICAL SCIENCES↗
Abrogation of Fam20c altered cell behaviors and BMP signaling of immortalized dental mesenchymal cells
Highlights: • Fam20c deficiency decreases the proliferation, mobility and mineralization of mouse immortalized dental mesenchymal cells. • Fam20c deficiency decreases the tooth mineralization, as well as the gene expression on dental mesenchymal differentiation. • Canonical and non-canonical BMP signaling pathways are declined in the mouse Fam20c-deficient dental mesenchyaml cell line. FAM20C mutations compromise the mineralization of skeleton and tooth in both human and mouse. Putatively, the mineralization disorder is attributed to the elevated fibroblast growth factor 23 (FGF23), which reduced the serum phosphorus by suppressing the reabsorption of phosphorus in kidney. Besides the regulation on systemic phosphorus homeostasis, FAM20C was also implicated to regulate cell behaviors and gene expression through a cell-autonomous manner. To identify the primary effects of Fam20c on dental mesenchymal cells, mouse Fam20c-deficient dental mesenchymal cells were generated by removing the floxed alleles from the immortalized mouse Fam20c{sup f/f} dental mesenchymal cells with Cre-expressing lentivirus. The removal of Fam20c exerted no impact on cell morphology, but suppressed the proliferation and mobility of the dental mesenchymal cells. Fam20c deficiency also significantly reduced the expression of Osterix, Runx2, type I Collagen a 1 (Col1a1), Alkaline phosphatase (Alpl) and the members of the small integrin-binding ligand, N-linked glycoprotein (SIBLING) family, but increased Fgf23 expression. Consistently, the in vitro mineralization of Fam20c-deficient dental mesenchymal cells was severely disabled. However, supplements of the non-collagenous proteins from wild type rat dentin failed to rescue the compromised mineralization, suggesting that the roles of FAM20C in tooth mineralization are more than phosphorylating local matrices and regulating systemic phosphorus metabolism. Moreover, the down-regulated BMP signaling pathways in the Fam20c deficient dental mesenchymal cells revealed that the kinase activity of FAM20C might be required to maintain BMP signaling. In summary, our study discloses that Fam20c indeed regulates cell behaviors and cell signaling pathway in a cell-autonomous manner.
60 APPLIED LIFE SCIENCES↗
TbasCO: trait-based comparative ‘omics identifies ecosystem-level and niche-differentiating adaptations of an engineered microbiome
A grand challenge in microbial ecology is disentangling the traits of individual populations within complex communities. Various cultivation-independent approaches have been used to infer traits based on the presence of marker genes. However, marker genes are not linked to traits with complete fidelity, nor do they capture important attributes, such as the timing of gene expression or coordination among traits. To address this, we present an approach for assessing the trait landscape of microbial communities by statistically defining a trait attribute as a shared transcriptional pattern across multiple organisms. Leveraging the KEGG pathway database as a trait library and the Enhanced Biological Phosphorus Removal (EBPR) model microbial ecosystem, we demonstrate that a majority (65%) of traits present in 10 or more genomes have niche-differentiating expression attributes. For example, while many genomes containing high-affinity phosphorus transporter pstABCS display a canonical attribute (e.g. up-regulation under phosphorus starvation), we identified another attribute shared by many genomes where transcription was highest under high phosphorus conditions. Taken together, we provide a novel framework for unravelling the functional dynamics of uncultivated microorganisms by assigning trait-attributes through genome-resolved time-series metatranscriptomics.
59 BASIC BIOLOGICAL SCIENCES↗
Exceptional gettering response of epitaxially grown kerfless silicon
The bulk minority-carrier lifetime in p- and n-type kerfless epitaxial (epi) crystalline silicon wafers is shown to increase >500× during phosphorus gettering. We employ kinetic defect simulations and microstructural characterization techniques to elucidate the root cause of this exceptional gettering response. Simulations and deep-level transient spectroscopy (DLTS) indicate that a high concentration of point defects (likely Pt) is “locked in” during fast (60 °C/min) cooling during epi wafer growth. The fine dispersion of moderately fast-diffusing recombination-active point defects limits as-grown lifetime, but can also be removed during gettering, confirmed by DLTS measurements. Synchrotron-based X-ray fluorescence microscopy indicates metal agglomerates at structural defects, yet the structural defect density is sufficiently low to enable high lifetimes. Consequently, after phosphorus diffusion gettering, epi silicon exhibits a higher lifetime than materials with similar bulk impurity contents but higher densities of structural defects, including multicrystalline ingot and ribbon silicon materials. Device simulations suggest a solar-cell efficiency potential of this material >23%.
DLTS↗
Communication: Effect of accidental mode degeneracy on Raman intensity in 2D materials: Hybrid functional study of bilayer phosphorene
Bulk black phosphorus has two optical phonon modes labeled as A{sub g}{sup 2} and B{sub 2u}, respectively, that are nearly degenerate in frequency. However, density functional theory calculations using local or semi-local functionals cannot reproduce this degeneracy. Here, we propose a hybrid functional approach aided by van der Waals (vdW) force fields, which can accurately describe the lattice dynamic and electronic properties of both bulk and few-layer black phosphorus (phosphorene). Using this approach we show that in bilayer phosphorene, the two Raman modes derived from the B{sub 2u} and A{sub g}{sup 2} modes could exhibit strong resonance as a result of the accidental degeneracy so that both modes could be observed in Raman experiment. Without the mode degeneracy, however, the Raman intensity of the B{sub 2u}-derived mode would be too weak to be observed. We further show that the accidental degeneracy is correlated to the applied strain, which enables Raman spectroscopy to be a powerful tool for characterizing built-in strains in 2D materials, e.g., due to the interaction with substrates, which has emerged as an important issue in vdW epitaxy.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Quantifying Growth of Three Common Bacterium on Phytic Acid: Investigating Effects of Media Composition
Microbes can produce a plethora of metabolites and enzymes that allow mobilization of various elements and nutrients in the soil, including phosphorus. Phosphorus is essential to plant growth; however, only a limited amount of it is in a bio-accessible inorganic form that can be utilized by most plants. Microbes can produce enzymes called phosphatase, which break down phytic acid (organic phosphorus) into bioavailable inorganic phosphate. My work aimed to understand how inorganic phosphate, phytic acid, and calcium in media affect the growth of Bacillus subtilis168 (B. subtilis), Escherichia coli K12 BW25113 (E. coli), Pseudomonas putida KT2440 (P. putida), and a strain of Pseudomonas putida AG5577_MS238 engineered to produce a phytase. Eight media were made to test how these components affect growth, and an additional two to understand the effects of multiple carbon sources versus one. It was observed that P. putida’s growth increased in the presence of phytic acid and was strongly driven by nitrate availability. Furthermore, it was able to initiate faster growth when multiple carbon sources were available rather than just one. E. coli’s growth seemed to be limited when inorganic phosphate was unavailable and little to no growth occurred when phytic acid, calcium, and inorganic phosphate were absent. B. subtilis was unable to substantially grow within 28 hrs in any of the mediums tested. The results of this research aid in understanding the growth responses of P. putida, E. coli, and B. subtilis on less accessible and bioavailable forms of phosphorus.
Black, Grace S.↗