Progress 10/01/20 to 09/30/21
Outputs
Target Audience:The target audience for this basic science project is primarily academic. The data collected during this project will help inform our understanding of phosphorus cycling and fluxes and particularly how phosphorus moves in the subsurface and is transported from the subsurface into other environmental compartments such as groundwater-fed lakes. However, forest biomass and, by extension, phosphorus demand is expected to increase in response to predicted future increases in atmospheric N deposition, CO2 levels and global temperatures. Phosphorus is a common limiting nutrient throughout the southeastern United States and improving our understanding of phosphorus budgets in forest ecosystems is critical for prediction of future ecosystem change, a topic of interest to stakeholders, regulators and the public. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided significant opportunity for training and professional development for my lab manager, 1 MS student and 1 undergraduate student. These individuals have had the opporutnity to gain valuable field and laboratory skills related to sample collection, processing and analyis. The MS student has also received training and experience with data interpretation, sophisticated data analysis software and data visualalization . This same MS student also had the opportunity to travel with me to SLAC in Palo Alto,CA to help conduct synchrotron-based analysis of our samples, gaining her first experience at a national laboratory and valuable exposure to cutting edge techniques in phosphorus analysis. How have the results been disseminated to communities of interest?During this project year, we have drafted and published one manuscript from this project in the Soil Science Society of America Journal. The citation for this work is provided below: Henshaw K, Bacon A, Cohen M, Vogel J, Judy JD. Subsurface phosphorus fluxes in a well-drained forest soil are small and dominated by particulates. Soil Sci Soc Am J. 2021;85:1299-1310. https://doi.org/10.1002/saj2.20258 What do you plan to do during the next reporting period to accomplish the goals?I plan to do the following during the next reporting period to address the project's specific five-year objectives: (1) Determine the proportion of soil P that is colloidal/colloid-associated as a function of vegetation type, soil characteristics and depth While we published these results, they have yet to be presented at a national meeting. We will be looking for an opportunity to present these results in this coming project year and are tentatively planning to do so at the Soil Science Society of America North America meeting. (2) Investigate vertical transport of colloidal/colloid-associated P using column studies and groundwater and surface water sampling While we published these results, they have yet to be presented at a national meeting. We will be looking for an opportunity to present these results in this coming project year and are tentatively planning to do so at the Soil Science Society of America North America meeting. (3) Analyze P speciation as a function of depth using X-ray diffraction, synchrotron-based X-ray fluorescence microprobe (μXRF) analysis and X-ray absorption analysis (XAS) ?We are in the process of preparing a second manuscript describing these results. We hope to have this manuscript submitted and published in the coming project year.
Impacts
What was accomplished under these goals?
The overall goal of this project is to investigate dissolved and colloidal P concentration, speciation and flux as a function of variables such as vegetative cover, soil properties, restoration approach and depth to water table. Our understanding of how nutrient storage and cycling is affected by the interaction between soil characteristics, vegetation properties (e.g., differences in root exudates and surface litter between tree species) and management practices in forest ecosystems is not well understood. The OSBS site offers the opportunity to systematically improve our understanding because it encompasses areas containing a variety of vegetation types (restored native long-leaf pine, pine plantations and successional hardwoods) on a variety of soil types. During this project year, we have drafted and published one manuscript from this project in the Soil Science Society of America Journal. The citation for this work is provided below: Henshaw K, Bacon A, Cohen M, Vogel J, Judy JD. Subsurface phosphorus fluxes in a well-drained forest soil are small and dominated by particulates. Soil Sci Soc Am J. 2021;85:1299-1310. https://doi.org/10.1002/saj2.20258 Specific five-year objectives and activities addressing them are listed below: (1) Determine the proportion of soil P that is colloidal/colloid-associated as a function of vegetation type, soil characteristics and depth We have collected and analyzed samples to address this objective. We found that the overwhelming majority of subsurface phosphorus flux was in the form of particulates >0.45 microns, that there was virtually zero dissolved phosphorus flux and that subsurface phosphorus flux in this system was low relative to inputs. During this project year, we have drafted and published one manuscript from this project in the Soil Science Society of America Journal describing results related to this objective. (2) Investigate vertical transport of colloidal/colloid-associated P using column studies and groundwater and surface water sampling We have collected and analyzed samples to address this objective. We found that the overwhelming majority of subsurface phosphorus flux was in the form of particulates >0.45 microns, that there was virtually zero dissolved phosphorus flux and that subsurface phosphorus flux in this system was low relative to inputs. During this project year, we have drafted and published one manuscript from this project in the Soil Science Society of America Journal describing results related to this objective. (3) Analyze P speciation as a function of depth using X-ray diffraction, synchrotron-based X-ray fluorescence microprobe (μXRF) analysis and X-ray absorption analysis (XAS) We have successfully conducted this analysis during, with our final analysis occurring during beamtime allocated at the Stanford Linear Accelerator facility in Palo Alto January 2020. Our analysis of these data revealed interesting trends with phosphorus speciation with depth at the study site. We are currently in the process of drafting a manuscript describing the results of our speciation analysis.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Henshaw K, Bacon A, Cohen M, Vogel J, Judy JD. Subsurface phosphorus fluxes in a well-drained forest soil are small and dominated by particulates. Soil Sci Soc Am J. 2021;85:12991310. https://doi.org/10.1002/saj2.20258
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Progress 10/01/19 to 09/30/20
Outputs
Target Audience:The target audience for this basic science project is primarily academic. The data collected during this project will help inform our understanding of phosphorus cycling and fluxes and particularly how phosphorus moves in the subsurface and is transported from the subsurface into other environmental compartments such as groundwater-fed lakes. However, forest biomass and, by extension, phosphorus demand is expected to increase in response to predicted future increases in atmospheric N deposition, CO2 levels and global temperatures. Phosphorus is a common limiting nutrient throughout the southeastern United States and improving our understanding of phosphorus budgets in forest ecosystems is critical for prediction of future ecosystem change, a topic of interest to stakeholders, regulators and the public. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided training opporutnities to one MS student (who has now graduated), a technician and several undergraduate research assistants. How have the results been disseminated to communities of interest?Results have been disseminated to communities of interest in the form of peer-reviewed manuscripts and presentation of results at international scientific conferences. What do you plan to do during the next reporting period to accomplish the goals?I plan to do the following during the next reporting period to address the project's specific five-year objectives: (1) Determine the proportion of soil P that is colloidal/colloid-associated as a function of vegetation type, soil characteristics and depth In the upcoming reporting year, we will continue the process of data processing and manuscript preparation of our efforts to address this objective. We are nearing submission of a manuscript In the upcoming reporting year, we will continue the process of data processing and manuscript preparation of our efforts to address this objective. We are nearing submission of a manuscript describing these results to Science of the Total Environment and plan to submit an abstract to present our final results at the Society of Environmental Toxicology and Chemistry national meeting in Portland in November 2021. (2) Investigate vertical transport of colloidal/colloid-associated P using column studies and groundwater and surface water sampling In the upcoming reporting year, we will continue the process of data processing and manuscript preparation of our efforts to address this objective. We are nearing submission of a manuscript describing these results to Science of the Total Environment and plan to submit an abstract to present our final results at the Society of Environmental Toxicology and Chemistry national meeting in Portland in November 2021. (3) Analyze P speciation as a function of depth using X-ray diffraction, synchrotron-based X-ray fluorescence microprobe (μXRF) analysis and X-ray absorption analysis (XAS) We will continue the process of data processing and manuscript preparation of our efforts to address this objective. We are in the process of preparing a second manuscript describing these results.
Impacts
What was accomplished under these goals?
Our understanding of how nutrient storage and cycling is affected by the interaction between soil characteristics, vegetation properties (e.g., differences in root exudates and surface litter between tree species) and management practices in forest ecosystems is not well understood. The OSBS site offers the opportunity to systematically improve our understanding because it encompasses areas containing a variety of vegetation types (restored native long-leaf pine, pine plantations and successional hardwoods) on a variety of soil types. During this project year, we have completed sample collection and analysis for several aspects of this work. The graduate student currently working on this project defended a thesis describing our progress thus far and graduated August 2020. We are also in the process of preparing manuscripts from this work for publication in peer-reviewed journals. Specific five-year objectives and activities addressing them are listed below: (1) Determine the proportion of soil P that is colloidal/colloid-associated as a function of vegetation type, soil characteristics and depth We have collected and analyzed samples to address this objective. We found that the overwhelming majority of subsurface phosphorus flux was in the form of particulates >0.45 microns, that there was virtually zero dissolved phosphorus flux and that subsurface phosphorus flux in this system was low relative to inputs. (2) Investigate vertical transport of colloidal/colloid-associated P using column studies and groundwater and surface water sampling We have collected and analyzed samples to address this objective. We found that the overwhelming majority of subsurface phosphorus flux was in the form of particulates >0.45 microns, that there was virtually zero dissolved phosphorus flux and that subsurface phosphorus flux in this system was low relative to inputs. (3) Analyze P speciation as a function of depth using X-ray diffraction, synchrotron-based X-ray fluorescence microprobe (μXRF) analysis and X-ray absorption analysis (XAS) We have successfully conducted this analysis during, with our final analysis occurring during beamtime allocated at the Stanford Linear Accelerator facility in Palo Alto January 2020. Our analysis of these data revealed interesting trends with phosphorus speciation with depth at the study site.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2020
Citation:
Henshaw, K. B. Examining the nature of subusrface phosphorus flux in well-drained forest soils, M.S. Thesis. University of Florida. (Embargoed)
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Progress 10/01/18 to 09/30/19
Outputs
Target Audience:The target audience for this basic science project is primarily academic. Thedata collected during this projectwill help inform our understanding of phosphorus cycling and fluxes and particularly how phosphorus moves in the subsurface and is transported from the subsurface into other environmental compartments such as groundwater-fed lakes. However,forest biomass and, by extension, phosphorusdemand is expected to increase in response to predicted future increases in atmospheric N deposition, CO2 levels and global temperatures. Phosphorus is a common limiting nutrient throughout the southeastern United States and improving our understanding of phosphorus budgets in forest ecosystems is critical for prediction of future ecosystem change, a topic of interest to stakeholders, regulators and the public. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided significant opportunity for training and professional development for my lab manager, 1 MSstudent and 1 undergraduate student. These individuals have had the opporutnity to gain valuable field and laboratory skills related to sample collection, processing and analyis. The MS student has also received training and experience with data interpretation, sophisticated data analysis software and data visualalization . This same MS student also had the opportunity to travel with me to SLAC in Palo Alto,CA to help conduct synchrotron-based analysis of our samples, gaining her first experience at a national laboratory and valuable exposure to cutting edge techniques in phosphorus analysis. How have the results been disseminated to communities of interest?We have submitted an abstract to the Society for Environmental Toxicology North America 2019 meeting, which was accepted for a poster presentation. This poster will be presented in November 2019. What do you plan to do during the next reporting period to accomplish the goals?In the coming project year, the graduate student currently working on this project is expected to complete and defend her MS thesis. Therefore, we anticipate that sample processing, analysis, data interpretation and data presentation will proceed significantly over the course of the upcoming reporting year. We also expect to end the project year nearing submission of at least one manuscript based upon this work. This graduate student has also submitted an abstract, which has been accepted, to present a poster illustrated her results thus far on this project at the Society for Environmental Toxicology and Chemistry North America meeting in Toronto in November, 2019. I plan to do the following during the next reporting period to address the project's specific five-year objectives: (1) Determine the proportion of soil P that is colloidal/colloid-associated as a function of vegetation type, soil characteristics and depth ?In the upcoming reporting year, we will proceed to process and analyze these soil samples. Data will then be processed, interpreted and prepared for presentation. (2) Investigate vertical transport of colloidal/colloid-associated P using column studies and groundwater and surface water sampling We will proceed with analyzing the P content of the recently collected groundwater P samples in the coming year. Data will then be processed, interpreted and prepared for presentation. (3) Analyze P speciation as a function of depth using X-ray diffraction, synchrotron-based X-ray fluorescence microprobe (μXRF) analysis and X-ray absorption analysis (XAS) We have additional beam time at SLAC in January 2020 and will be returning to Stanford then to continue analyzing the speciation of our collected soil samples. Upon completion of this analysis, significant time will be invested in data processing, interpretation and presentation. We also intend to use these data as a capability/utility demonstration for use in the application of grant funds for other projects for while these sophisticated techniques would add value.
Impacts
What was accomplished under these goals?
During this project year, we have completed sampling that will allow for the completion of soil and groundwater data sets crucial to the specific objectives of the project. We also successfully obtained beamtime at a synchrotron facility, analyzed our first samples there and developed the capability to interpret and analyze these data. Specific five-year objectives and activities addressing them are listed below: (1) Determine the proportion of soil P that is colloidal/colloid-associated as a function of vegetation type, soil characteristics and depth We elected to re-sample soil in May 2019 as we determined that obtaining soil samples from deeper depths than were sampled during the previous reporting year would be ideal. Samples were collected from our three experimental sites from the following depths (cm): 0-10, 10-20, 20-60, 60-90, 90-120, 120-160, and 160-200. Three plots per site were sampled. Each plot sample was treated as a replicate with a total of three replicate samples (for each depth) representing each site. Samples were transported to Gainesville, FL, sieved (2 mm2) and air-dried for 48 hours and stored for future analysis. We also obtained samples from soil cores taken down to 6 meters from another faculty member in our department. These samples were obtained for the purposes of these analyses, as well as for analysis of P speciation (Objective 3). (2) Investigate vertical transport of colloidal/colloid-associated P using column studies and groundwater and surface water sampling We elected to resample groundwater, as the original, existing wells we sampled in the previous reporting year were extremely deep and it was difficult to properly sample these wells. As a result, the samples collected in the previous reporting year were questionable. To address this challenge, during Summer 2019 (June-August), we installed 9 new wells, with 3 being installed at each of the three experimental sites. Individual wells were located downslope of a corresponding plot at each site. Wells were made from PVC with a solid above ground portion joined with slotted well screen placed below ground. The well-screen encompassed the entire profile from surface to end cap. A total of 9 groundwater samples were taken weekly beginning June 5th, 2019 through August 2019. A peristaltic pump was used to collect the samples. Wells were purged 3 times the total well volume prior to collection. Groundwater samples were then placed on ice packs in a cooler and transported to Gainesville, FL for processing. Once in Gainesville, an aliquot of 30 mL was collected from the sample and filtered through a 0.45 µm syringe filter into a HDPE sample bottle. Another 4 mL aliquot of sample was pipetted into a 3 kDa centrifuge filter and centrifuged at 4000 rcf for 20 minutes. Remaining groundwater sample was kept unfiltered for total P analysis. Immediately following filtration and processing, samples were frozen at -20°C and stored for future analysis. (3) Analyze P speciation as a function of depth using X-ray diffraction, synchrotron-based X-ray fluorescence microprobe (μXRF) analysis and X-ray absorption analysis (XAS) ?I submitted a successful proposal for beamtime at the Stanford Linear Accelerator (SLAC). In July 2019, my graduate student (Kalani) and I traveled to SLAC and analyzed soil samples for this project. Samples were analyzed at beamline 14-3 to determine phosphorus speciation via x-ray absorption spectroscopy. These samples include phosphorus reference compounds as well as soil samples from various depths. We analyzed other soil samples embedded in epoxy resin at beamline 2-3 via x-ray fluorescence mapping to determine their colocalization with other elements.
Publications
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Progress 12/04/17 to 09/30/18
Outputs
Target Audience:A presentation entitled "Dissolved and colloidal phosphorus flux as a function of vegetative cover, soil properties and depth in well-drained forest soils" was given describing this project at the Biodiversity Symposium at the University of Florida on May 7, 2018. The target audience was graduate students, faculty and other professional scientists. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training in analytical and field methods has ben provided to one graduate student, one chemist, one undergraduate and one Florida high school student, the latter of which participatedin this project as aStudent Science Training Program (SSTP) trainee. How have the results been disseminated to communities of interest?A presentation entitled "Dissolved and colloidal phosphorus flux as a function of vegetative cover, soil properties and depth in well-drained forest soils" (previously described in the "Target Audience" section) was given describing this project at the Biodiversity Symposium at the University of Florida on May 7, 2018. The target audience was graduate students, faculty and other professional scientists. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, we intend to makethe following progress on our experiment objectives: (1) Determine the proportion of soil P that is colloidal/colloid-associated as a function of vegetation type, soil characteristics and depth Vegetative species composition at each site will be assessed within the 50 x 50 m plots. Within each plot, understory biomass and species composition will be estimated in eight 1 m x 1 m randomly located sub-plots. At each site 3 meter deep soil cores will be collected and soil from different depth ranges will be separated from the core, freeze-dried and homogenized. Samples will be processed similarly to those collected from 0-60 cm during Phase 1. (2)Investigate vertical transport of colloidal/colloid-associated P using column studies and groundwater and surface water sampling Colloidal P will be isolated from soil samples through an operationally-defined method for the collection of water-dispersible clay (WDC). WDC is often used as a proxy for soil-borne mobile colloids and is isolated using a modified micropipette method (Burt 1993, Kaplan 1993, de Jonge 2004). The colloidal/colloid-associated P within the WDC will then be analyzed, as well as the P present in < 3 kDa filtrates of the WDC suspensions. The P present in the < 3 kDa filtrates will be operationally defined as low-molecular weight dissolved inorganic phosphorus (DIP) and DOP. Total, <0.45 µm and < 3 kDa P will be analyzed using EPA method 3050B (EPA 1996) and the ICP-OES in the Soil and Water Sciences department. Unfractionated and < 0.45 µm and < 3 kDa litter leachate samples and groundwater samples will be analyzed for total P using EPA method 365.3 (EPA 1978) and a UV-VIS spectrophotometer. Soil and litter samples will be analyzed for total P using EPA method 3050B (EPA 1996) and the ICP-OES. The difference between total P and dissolved P concentrations found in 3 kDa filtrates will give the particulate P (including particulates < 0.45 µm) concentration in each sample. (3) Analyze P speciation as a function of depth using X-ray diffraction, synchrotron-based X-ray fluorescence microprobe (µXRF) analysis and X-ray absorption analysis (XAS) Selected samples will be analyzed by XAS to determine P speciation as a function of depth. For this analysis, proposals have beensubmitted to the National Synchrotron Light Source II at Brookhaven National Laboratory and to the Stanform Linear Accelerator CEenter. Spectra will be collected on a suite of inorganic and organic standards. If we are awarded beam time, inorganic standards will include materials such as hydroxyapatite, variscite, hydrated iron phosphate and a sample of commercially available NPK (13-13-13) fertilizer. Organic standards will include materials such as adenosine tri-phosphate and inositol hexakisphosphate. Spectra will be collected from samples and using spectra collected from standards, the speciation of the P within each sample will be determined using linear combination fitting (LCF).
Impacts
What was accomplished under these goals?
During this reporting period, we have made the following progress on our experiment objectives: (1) Determine the proportion of soil P that is colloidal/colloid-associated as a function of vegetation type, soil characteristics and depth (2) Investigate vertical transport of colloidal/colloid-associated P using column studies and groundwater and surface water sampling Progress on Objectives 1 and 2 has centered around sample collection and analytical method development. Samples have been collected from a variety of samples sites at OSBS to characterize the nature and magnitude of P fluxes including: Litter P and its flux to soil Soil P and its flux to groundwater Groundwater P and its flux to groundwater-fed lake Sample sites. Sites at Lakes McCloud, Barco and Anderson Que were selected for Phase 1 work to facilitate systematic examination of the importance of vegetation type, soil characteristics and restoration approaches at OSBS. According to FNAI (Florida Natural Areas Inventory), all three study sites are sandhill upland lakes: lentic water bodies largely derived from lateral groundwater seepage. McCloud is surrounded by upland hardwood forest and upland mixed forest. Anderson Que and Barco are both surrounded by xeric uplands dominated by sandhill forest. Three plots were established at each site. At McCloud, three plots were chosen based on soil type with one plot in three different soil type (Apopka, Tavares and Candler). At Anderson Que and Barco, plots were established based on forest type, with all plots representing sandhill vegetation. Soil Sampling. The sampling area of each plot was 50 m x 50 m and soil was sampled at 0-10, 10-20, 20-40 and 40-60 cm. Sixteen subsamples at each depth increment were taken across the entire plot. The 16 subsamples were composited into a single sample. Three composited subsamples were collected at each depth for each plot. Samples were transported back to the lab and air-dried for 48 hours. Total precipitation and throughfall. Total precipitation was measured at the OSBS National Ecological Observatory Network (NEON) station. Throughfall, or precipitation penetrating the forest canopy, was sampled in 7-day intervals from May 31st to August 30th, 2018. One plot was selected at each of the three sites for the installation of 12 throughfall collectors. Throughfall collectors were 150 mm (diameter) funnels fitted and taped to 2 L plastic wide-mouth bottles tied to stakes. On the sampling day, throughfall was measured using a graduated cylinder. Litterfall. Litterfall sampling occurred in 7-day intervals from May 31st to August 30th, 2018. Four 70 cm2 litter ground traps were placed in each plot in every site for a total of 36 traps. Traps were spatially installed according to NEON protocol guidelines for litterfall collection. After collection, litter was dried at 40?C for 24-48 hours, weighed, ground and stored at room temperature for future analyses (phosphorus/carbon). Litter leachate sampling. Litter leachate, or water percolating through forest floor litter, was collected using lysimeters made from 50 cm long sections of PVC pipe and cut in half longitudinally. Carbon fiber screens were cut to match the dimensions and secured across the open face of PVC with glue. A hole was drilled in the bottom of one end where tubing was connected and secured with glue to ensure sample would flow via gravity into a 1-L amber bottle. Lysimeters were installed March 26-29 and left to equilibrate for 2 months. During this time, litter leachate was discarded. At Lake McCloud, a 50 cm trench was dug and mineral horizons within 20 cm were laterally excavated by hand. The lysimeters were then placed into excavated side trench, underneath organic litter layer. At Lake Anderson and Lake Barco, forest litter was raked from a 5 cm x 50 cm area and swept onto a tarp. A 5 cm x 50 cm trench was then dug and the lysimeter was placed into the trench. The litter was then swept back on top of the lysimeter. Litter leachate samples were composited with other samples collected from the same plot. A 125 mL aliquot of unfiltered, composite sample was collected into a HDPE sample bottle. Another aliquot was collected from the composite sample and filtered through a 0.45 µm syringe filter. Lastly, a third aliquot of composite sample was filtered using a 3 kilodalton (kDa) centrifuge filter. After processing, samples were placed in the freezer at -20°C for P and carbon analyses. Groundwater sampling. Groundwater samples were taken from 3 NEON wells located on the North/North-west slopes surrounding Lake Barco. Sampling occurred in 7-day intervals from May 31st to August 16th. Groundwater samples were processed using the same procedures that were used for the litter leachate samples, after which samples were frozen at -20°C for later P and carbon analyses. (3) Analyze P speciation as a function of depth using X-ray diffraction, synchrotron-based X-ray fluorescence microprobe (µXRF) analysis and X-ray absorption analysis (XAS) I have submitted proposals to the National Synchrotron Light Source II (NSLS-II) as well as the Stanford Linear Accelerator Center (SLAC) requesting beam time for the analyses proposed in this project. The proposals received good reviews and I am optimistic that we will be awarded beam time.
Publications
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Judy, J. D. Biodiversity Symposium, University of Florida. May 7, 2018, Gainesville, Florida. Invited Oral Presentation. Dissolved and colloidal phosphorus flux as a function of vegetative cover, soil properties and depth in well-drained forest soils .
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