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Publication Automated Mapping of Historical Native American Land Allotments at the Standing Rock Sioux Reservation Using Geographic Information Systems(MDPI, 2021-03-20) Meisel, Joshua Jerome; Egbert, Stephen L.; Brewer, Joseph P. II; Li, XingongThe General Allotment Act of 1887, also known as the Dawes Act, established the legal basis for the United States government to break up remaining tribally-owned reservation lands in the U.S. by allotting individual parcels to tribal members and selling the remaining “surplus.” This research explores the processes involved in mapping these historical allotments and describes a method to automatically generate spatial data of allotments. A custom geographic information systems (GIS) tool was created that takes tabular based allotment land descriptions and digital Public Land Survey (PLSS) databases to automatically generate spatial and attribute data of those land parcels. The Standing Rock Sioux Tribe of North and South Dakota was used as the initial study area to test the mapping technique, which resulted in successfully auto-mapping over 99.1% of allotted lands on the reservation, including the smallest aliquot parcels. This GIS technique can be used to map any tribal lands or reservation with allotment data available, and currently it can be used to map over 120 individual reservations using publicly available data from the Bureau of Land Management (BLM).Publication Arbuscular Mycorrhizal Fungi Taxa Show Variable Patterns of Micro-Scale Dispersal in Prairie Restorations(Frontiers Media, 2022-07-22) Tipton, Alice G.; Nelsen, Donald; Koziol, Liz; Duell, Eric B.; House, Geoffrey; Wilson, Gail W. T.; Schultz, Peggy A.; Bever, James D.Human land use disturbance is a major contributor to the loss of natural plant communities, and this is particularly true in areas used for agriculture, such as the Midwestern tallgrass prairies of the United States. Previous work has shown that arbuscular mycorrhizal fungi (AMF) additions can increase native plant survival and success in plant community restorations, but the dispersal of AMF in these systems is poorly understood. In this study, we examined the dispersal of AMF taxa inoculated into four tallgrass prairie restorations. At each site, we inoculated native plant species with greenhouse-cultured native AMF taxa or whole soil collected from a nearby unplowed prairie. We monitored AMF dispersal, AMF biomass, plant growth, and plant community composition, at different distances from inoculation. In two sites, we assessed the role of plant hosts in dispersal, by placing known AMF hosts in a “bridge” and “island” pattern on either side of the inoculation points. We found that AMF taxa differ in their dispersal ability, with some taxa spreading to 2-m in the first year and others remaining closer to the inoculation point. We also found evidence that AMF spread altered non-inoculated neighboring plant growth and community composition in certain sites. These results represent the most comprehensive attempt to date to evaluate AMF spread.Publication Rebuild the Academy: Supporting academic mothers during COVID-19 and beyond(Public Library of Science, 2021-03-09) Fulweiler, Robinson W.; Davies, Sarah W.; Biddle, Jennifer F.; Burgin, Amy J.; Cooperdock, Emily H. G.; Hanley, Torrance C.; Kenkel, Carly D.; Marcarelli, Amy M.; Matassa, Catherine M.; Mayo, Talea L.; Santiago-Vàzquez, Lory Z.; Traylor-Knowles, Nikki; Ziegler, MarenThe issues facing academic mothers have been discussed for decades. Coronavirus Disease 2019 (COVID-19) is further exposing these inequalities as womxn scientists who are parenting while also engaging in a combination of academic related duties are falling behind. These inequities can be solved by investing strategically in solutions. Here we describe strategies that would ensure a more equitable academy for working mothers now and in the future. While the data are clear that mothers are being disproportionately impacted by COVID-19, many groups could benefit from these strategies. Rather than rebuilding what we once knew, let us be the architects of a new world.Publication Building Community Resilience: A Proactive, Measurable, Scalable, and Comprehensive Resilience Planning and Forecasting Model(University of Kansas, 2021-11-30) Schulte, Scott A.; Fannin-Hughes, Ian J.; Byers, Heather M.Historically, community resilience planning has been disaster-focused, reactive, and left little room to build increased sustainability to face exponentially increasing climate change impacts. Defining sustainability and resilience as both separate and interdependent characteristics of a community presents challenges for comprehensive and scalable resilience planning frameworks. However, communities can improve their resilience and sustainability within their unique set of risks and stressors if provided a framework that accounts for their Capital Stocks and Resilience Properties, identifies critical performance gaps, grades existing resilience, helps forecast potential gains from implementation strategies, and measures progress. The authors and a team of University of Kansas Environmental Assessment program students expanded, adapted and applied an existing, comprehensive, resilience planning framework in cooperation with a rural municipality, a suburban city, and a tribal nation. The teams completed a vulnerability assessment, SWOT (strengths, weaknesses, opportunities, threats) analysis, resilience screening, peer community assessment, community resilience scoring, and developed resilience-building strategies. The result was a comprehensive, rigorous, scalable resilience assessment and planning framework with an adaptable grading and forecasting system. This expanded framework, named the Community Resilience Assessment and Forecasting Tool (CRAFT), reveals facets of resilience overlooked by traditional planning processes and proactively identifies critical improvement areas with actionable specificity, tied to performance metrics, empowering communities of every size to move toward greater resilience and sustainability.Publication Seasonal Salinization Decreases Spatial Heterogeneity of Sulfate Reducing Activity(MDPI, 2019-04-02) Schoepfer, Valerie A.; Burgin, Amy J.; Loecke, Terrance D.; Helton, Ashley M.Evidence of sulfate input and reduction in coastal freshwater wetlands is often visible in the black iron monosulfide (FeS) complexes that form in iron rich reducing sediments. Using a modified Indicator of Reduction in Soils (IRIS) method, digital imaging, and geostatistics, we examine controls on the spatial properties of FeS in a coastal wetland fresh-to-brackish transition zone over a multi-month, drought-induced saltwater incursion event. PVC sheets (10 × 15 cm) were painted with an iron oxide paint and incubated vertically belowground and flush with the surface for 24 h along a salt-influenced to freshwater wetland transect in coastal North Carolina, USA. Along with collection of complementary water and soil chemistry data, the size and location of the FeS compounds on the plate were photographed and geostatistical techniques were employed to characterize FeS formation on the square cm scale. Herein, we describe how the saltwater incursion front is associated with increased sulfate loading and decreased aqueous Fe(II) content. This accompanies an increased number of individual FeS complexes that were more uniformly distributed as reflected in a lower Magnitude of Spatial Heterogeneity at all sites except furthest downstream. Future work should focus on streamlining the plate analysis procedure as well as developing a more robust statistical based approach to determine sulfide concentration.Publication Reply to Wassmann et al.: More data at high sampling intensity from medium- and intense-intermittently flooded rice farms is crucial(National Academy of Sciences, 2019-01-22) Kritee, Kritee; Rudek, Joseph; Proville, Jeremy; Adhya, Tapan K.; Loecke, Terrance D.; Nair, Drishya; Ahuja, Richie; Hamburg, Steven P.Here, we briefly respond to critique of our study (1) by Wassmann et al. (2). A detailed response to their letter is available online (edf.org/riceN2O).Publication Mesophilic microorganisms build terrestrial mats analogous to Precambrian microbial jungles(Nature Research, 2019-09-20) Finke, N.; Simister, R. L.; O’Neil, A. H.; Nomosatryo, S.; Henny, C.; MacLean, L. C.; Canfield, D. E.; Konhauser, K.; Lalonde, S. V.; Fowle, David Allan; Crowe, S. A.Development of Archean paleosols and patterns of Precambrian rock weathering suggest colonization of continents by subaerial microbial mats long before evolution of land plants in the Phanerozoic Eon. Modern analogues for such mats, however, have not been reported, and possible biogeochemical roles of these mats in the past remain largely conceptual. We show that photosynthetic, subaerial microbial mats from Indonesia grow on mafic bedrocks at ambient temperatures and form distinct layers with features similar to Precambrian mats and paleosols. Such subaerial mats could have supported a substantial aerobic biosphere, including nitrification and methanotrophy, and promoted methane emissions and oxidative weathering under ostensibly anoxic Precambrian atmospheres. High C-turnover rates and cell abundances would have made these mats prime locations for early microbial diversification. Growth of landmass in the late Archean to early Proterozoic Eons could have reorganized biogeochemical cycles between land and sea impacting atmospheric chemistry and climate.Publication Mato Grosso, Brazil, ground reference data for crop years 2005-2013 (Dataset)(2017) Kastens, Jude H.; Brown, J. Christopher; Coutinho, Alexandre Camargo; Bishop, Christopher R.; Esquerdo, Júlio César D. M.The points associated with ‘ground reference set 1’ and ‘ground reference set 2’ identify fields where agricultural cover information was obtained by Embrapa through farmer interviews. The points associated with ‘supplemental pasture/cerrado’ were identified using aerial and satellite imagery to provide additional ground reference samples for the pasture/cerrado data class. See the following publication for more information (please cite this reference when using these data): Kastens, J.H., J.C. Brown, A.C. Coutinho, C.R. Bishop, and J.C.D.M. Esquerdo (2017). Soy moratorium impacts on soybean and deforestation dynamics in Mato Grosso, Brazil. PLoS ONE, 12(4): e0176168. DOI: 10.1371/journal.pone.0176168 (https://doi.org/10.1371/journal.pone.0176168 ) Annual attributes beginning with ‘plos’ provide a binary indicator for whether or not the sample was used for development of the 14-year Mato Grosso land cover map set described in the PLOS ONE study (1 = used, 0 = not used). For additional information regarding class structure determination and data preparation and filtering, see the following: Brown, J.C., J.H. Kastens, A.C. Coutinho, D.C. Victoria, and C.R. Bishop (2013). Classifying Multiyear Agricultural Land Use Data from Mato Grosso Using Time-Series MODIS Vegetation Index Data. Remote Sensing of Environment, 130(3): 39-50. DOI: 10.1016/j.rse.2012.11.009 (http://dx.doi.org/10.1016/j.rse.2012.11.009)Publication Spatiotemporal predictions of soil properties and states in variably saturated landscapes(American Geophysical Union, 2017-06-19) Franz, Trenton E.; Loecke, Terrance D.; Burgin, Amy J.; Zhou, Yuzhen; Le, Tri; Moscicki, DavidUnderstanding greenhouse gas (GHG) fluxes from landscapes with variably saturated soil conditions is challenging given the highly dynamic nature of GHG fluxes in both space and time, dubbed hot spots, and hot moments. On one hand, our ability to directly monitor these processes is limited by sparse in situ and surface chamber observational networks. On the other hand, remote sensing approaches provide spatial data sets but are limited by infrequent imaging over time. We use a robust statistical framework to merge sparse sensor network observations with reconnaissance style hydrogeophysical mapping at a well‐characterized site in Ohio. We find that combining time‐lapse electromagnetic induction surveys with empirical orthogonal functions provides additional environmental covariates related to soil properties and states at high spatial resolutions (~5 m). A cross‐validation experiment using eight different spatial interpolation methods versus 120 in situ soil cores indicated an ~30% reduction in root‐mean‐square error for soil properties (clay weight percent and total soil carbon weight percent) using hydrogeophysical derived environmental covariates with regression kriging. In addition, the hydrogeophysical derived environmental covariates were found to be good predictors of soil states (soil temperature, soil water content, and soil oxygen). The presented framework allows for temporal gap filling of individual sensor data sets as well as provides flexible geometric interpolation to complex areas/volumes. We anticipate that the framework, with its flexible temporal and spatial monitoring options, will be useful in designing future monitoring networks as well as support the next generation of hyper‐resolution hydrologic and biogeochemical models.Publication Highway Infrastructure, Protected Areas, and Orchid Bee Distribution and Conservation in the Brazilian Amazon(Scientific Research Publishing, 2017-07-28) Oliveira, Marcio Luiz de; Brown, John C.; Moreira, Marcelo P.Scientists regularly lament that development and habitat destruction in once isolated and distant areas are promoting species extinction before species can even be known by science. In the Brazilian Amazon, the government’s Plan for Growth Acceleration in part involves major improvements and expansion of highways. Such infrastructure has long been linked to the main causes of deforestation in this region. It is essential for scientists to assess where to target biodiversity collections in relation to the location of road development and existing protected areas. The objective of this study was to amass all of the records of occurrence of orchid bees in digital form, in order to obtain a spatial picture of our knowledge thus far and to make recommendations about priority areas for future collections and the role of protected areas in species conservation. The collection data used for this study come from various collection efforts, and were also gathered from the literature. The collection data were then imported into a Geographic Information System, making it possible to integrate other spatial data layers such as highways, conservation units, indigenous lands and forest cover. Results show a major need for collections along the BR 163 and BR 230 highways, heavily deforested areas with few conservation units. We suggest the creation of conservation units and recommend that abandoned areas be allowed to remain fallow as a way to help save additional biodiversity in the area of influence of these two main highways.Publication Evidence for the Paleoethnobotany of the Neanderthal: A Review of the Literature(Hindawi Publishing Corporation, 2016-09-29) Shipley, Gerhard P.; Kindscher, KellyOur perception of our closest human relatives, the Neanderthals, has evolved in the last few decades from brutish ape-men to intelligent archaic human peoples. Our understanding and appreciation of their cultural sophistication has only recently extended to their diet. Only within the last few years, with new techniques and a shift in focus, have we begun to truly investigate and understand the role of plants in their diet and culture. The more we learn about Neanderthals, the more we realize that biological and cultural distinctions between them and us were relatively small. Given that we coexisted and likely interacted with them for thousands of years, the more we learn about them, the better we may understand our own past. In that light, we review the current evidence, derived from such sources as plant remains (e.g., starch, pollen, phytoliths, and seeds) in soil and dental calculus, dental and tool wear, coprolites, and genetics, for Neanderthal’s nutritional, medicinal, and ritual use of plants, which includes 61 different taxa from 26 different plant families found at 17 different archaeological sites. Further, we updated and standardized botanical nomenclature from many sources published over many decades to provide a more stable foundation for future work.Publication The role of interface organizations in science communication and understanding(Ecological Society of America, 2010-08-01) Osmond, Deanna L.; Nadkarni, Nalini M.; Driscoll, Charles T.; Andrews, Elaine; Gold, Arthur J.; Broussard Allred, Shorna R.; Berkowitz, Alan R.; Klemens, Michael W.; Loecke, Terrance D.; McGarry, Mary Ann“Interface” organizations are groups created to foster the use of science in environmental policy, management, and education. Here we compare interface organizations that differ in spatial scale, modes of operation, and intended audience to illustrate their diversity and importance in promoting the application of science to environmental issues. There has been exciting recent growth in the nature and extent of activities by interface organizations and in new methods for science communication and engagement. These developments can help scientists – who face personal and institutional challenges when attempting to convey the results of their research to various audiences – interact with society on specific issues in specific places, and with a wide range of non-traditional audiences. The ongoing mission for these organizations should be to move beyond simply increasing awareness of environmental problems to the creation of solutions that result in genuine environmental improvements.Publication Gila River Flow Needs Assessment(Western New Mexico University, 2016-02) Gori, David; Sooper, Martha S.; Soles, Ellen S.; Stone, Mark; Morrison, Ryan; Turner, Thomas F.; Propst, David L.; Grafin, Gregg; Kindscher, KellyThe Nature Conservancy and a team of 14 academic partners (the project team) received funding from the Bureau of Reclamation’s WaterSMART program and the Desert Landscape Conservation Cooperative in 2012 to conduct this Gila River Flow Needs Assessment. The assessment describes the existing condition of the Gila River in the Cliff-Gila Valley and examines the potential impacts of CUFA diversion and climate change on the riparian and aquatic ecosystem. The project team was assisted by 35 academic, agency and consulting scientists who have expertise in some aspect of the Gila River’s hydrology and ecology. This larger team of scientists provided input on a review draft of this assessment at a workshop in January 2014. This assessment report includes 12 chapters written by project team scientists. Two chapters summarize workshop findings, including input of the larger team of scientists on how flows shape the ecosystem and how these interactions may be affected by flow alterations due to CUFA diversion and climate change.Publication Nitrous oxide emission from denitrification in stream and river networks(National Academy of Sciences, 2011-11-11) Beaulieu, Jake J.; Tank, Jennifer L.; Hamilton, Stephen K.; Wollheim, Wilfred M.; Hall, Robert O.; Burgin, Amy J.Nitrous oxide (N2O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N2O via microbial denitrification that converts N to N2O and dinitrogen (N2). The fraction of denitrified N that escapes as N2O rather than N2 (i.e., the N2O yield) is an important determinant of how much N2O is produced by river networks, but little is known about the N2O yield in flowing waters. Here, we present the results of whole-stream 15N-tracer additions conducted in 72 headwater streams draining multiple land-use types across the United States. We found that stream denitrification produces N2O at rates that increase with stream water nitrate (NO3−) concentrations, but that <1% of denitrified N is converted to N2O. Unlike some previous studies, we found no relationship between the N2O yield and stream water NO3−. We suggest that increased stream NO3− loading stimulates denitrification and concomitant N2O production, but does not increase the N2O yield. In our study, most streams were sources of N2O to the atmosphere and the highest emission rates were observed in streams draining urban basins. Using a global river network model, we estimate that microbial N transformations (e.g., denitrification and nitrification) convert at least 0.68 Tg·y−1 of anthropogenic N inputs to N2O in river networks, equivalent to 10% of the global anthropogenic N2O emission rate. This estimate of stream and river N2O emissions is three times greater than estimated by the Intergovernmental Panel on Climate Change. Humans have more than doubled the availability of fixed nitrogen (N) in the biosphere, particularly through the production of N fertilizers and the cultivation of N-fixing crops (1). Increasing N availability is producing unintended environmental consequences including enhanced emissions of nitrous oxide (N2O), a potent greenhouse gas (2) and an important cause of stratospheric ozone destruction (3). The Intergovernmental Panel on Climate Change (IPCC) estimates that the microbial conversion of agriculturally derived N to N2O in soils and aquatic ecosystems is the largest source of anthropogenic N2O to the atmosphere (2). The production of N2O in agricultural soils has been the focus of intense investigation (i.e., >1,000 published studies) and is a relatively well constrained component of the N2O budget (4). However, emissions of anthropogenic N2O from streams, rivers, and estuaries have received much less attention and remain a major source of uncertainty in the global anthropogenic N2O budget. Microbial denitrification is a large source of N2O emissions in terrestrial and aquatic ecosystems. Most microbial denitrification is a form of anaerobic respiration in which nitrate (NO3−, the dominant form of inorganic N) is converted to dinitrogen (N2) and N2O gases (5). The proportion of denitrified NO3− that is converted to N2O rather than N2 (hereafter referred to as the N2O yield and expressed as the mole ratio) partially controls how much N2O is produced via denitrification (6), but few studies provide information on the N2O yield in streams and rivers because of the difficulty of measuring N2 and N2O production in these systems. Here we report rates of N2 and N2O production via denitrification measured using whole-stream 15NO3−-tracer experiments in 72 headwater streams draining different land-use types across the United States. This project, known as the second Lotic Intersite Nitrogen eXperiment (LINX II), provides unique whole-system measurements of the N2O yield in streams. Although N2O emission rates have been reported for streams and rivers (7, 8), the N2O yield has been studied mostly in lentic freshwater and marine ecosystems, where it generally ranges between 0.1 and 1.0%, although yields as high as 6% have been observed (9). These N2O yields are low compared with observations in soils (0–100%) (10), which may be a result of the relatively lower oxygen (O2) availability in the sediments of lakes and estuaries. However, dissolved O2 in headwater streams is commonly near atmospheric equilibrium and benthic algal biofilms can produce O2 at the sediment–water interface, resulting in strong redox gradients more akin to those in partially wetted soils. Thus, streams may have variable and often high N2O yields, similar to those in soils (11). The N2O yield in headwater streams is of particular interest because much of the NO3− input to rivers is derived from groundwater upwelling into headwater streams. Furthermore, headwater streams compose the majority of stream length within a drainage network and have high ratios of bioreactive benthic surface area to water volume (12).Publication Have we overemphasized the role of denitrification in aquatic ecosystems? A review of nitrate removal pathways(Ecological Society of America, 2007-03-01) Burgin, Amy J.; Hamilton, Stephen K.The removal of nitrogen (N) in aquatic ecosystems is of great interest because excessive nitrate in groundwater and surface water is a growing problem. High nitrate loading degrades water quality and is linked to eutrophication and harmful algal blooms, especially in coastal marine waters. Past research on nitrate removal processes has emphasized plant or microbial uptake (assimilation) or respiratory denitrification by bacteria. The increasing application of stable isotopes and other tracer techniques to the study of nitrate removal has yielded a growing body of evidence for alternative, microbially mediated processes of nitrate transformation. These include dissimilatory (the reduction of nitrogen into other inorganic compounds, coupled to energy producing processes) reduction of nitrate to ammonium (DNRA), chemoautotrophic denitrification via sulfur or iron oxidation, and anaerobic ammonium oxidation (anammox), as well as abiotic nitrate removal processes. Here, we review evidence for the importance of alternative nitrate removal pathways in aquatic ecosystems and discuss how the possible prevalence of these pathways may alter views of N cycling and its controls. These alternative pathways are of particular importance for the management of excess N in the environment, especially in cases where nitrate is transformed to ammonium, a biologically available and less mobile N form, rather than to dinitrogen gas.Publication Nitrate removal in stream ecosystems measured by 15N addition experiments: Denitrification(Association for the Sciences of Limnology and Oceanography, 2009-05-12) Mullholland, Patrick J.; Hall, Robert O.; Sobota, Daniel J.; Dodds, Walter K.; Findlay, Stuart E. G.; Grimm, Nancy B.; Hamilton, Stephen K.; McDowell, William H.; O'Brien, Jonathan M.; Burgin, Amy J.We measured denitrification rates using a field 15NO3− tracer-addition approach in a large, cross-site study of nitrate uptake in reference, agricultural, and suburban-urban streams. We measured denitrification rates in 49 of 72 streams studied. Uptake length due to denitrification (SWdenn) ranged from 89 m to 184 km (median of 9050 m) and there were no significant differences among regions or land-use categories, likely because of the wide range of conditions within each region and land use. N2 production rates far exceeded N2O production rates in all streams. The fraction of total NO3− removal from water due to denitrification ranged from 0.5% to 100% among streams (median of 16%), and was related to NH4+ concentration and ecosystem respiration rate (ER). Multivariate approaches showed that the most important factors controlling SWden were specific discharge (discharge / width) and NO3− concentration (positive effects), and ER and transient storage zones (negative effects). The relationship between areal denitrification rate (Uden) and NO3− concentration indicated a partial saturation effect. A power function with an exponent of 0.5 described this relationship better than a Michaelis-Menten equation. Although Uden increased with increasing NO3− concentration, the efficiency of NO3− removal from water via denitrification declined, resulting in a smaller proportion of streamwater NO3− load removed over a given length of stream. Regional differences in stream denitrification rates were small relative to the proximate factors of NO3− concentration and ecosystem respiration rate, and land use was an important but indirect control on denitrification in streams, primarily via its effect on NO3− concentration.Publication Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake(Association for the Sciences of Limnology and Oceanography, 2009-05-12) Hall, Robert O.; Tank, Jennifer L.; Sobota, Daniel J.; Mullholland, Patrick J.; O'Brien, Jonathan M.; Dodds, Walter K.; Webster, Jackson R.; Valett, H. Maurice; Burgin, Amy J.We measured uptake length of 15NO3− in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO3− uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural (reference), suburban-urban, and agricultural land uses. Study streams spanned a range of human land use to maximize variation in NO3− concentration, geomorphology, and metabolism. We tested a causal model predicting controls on NO3− uptake length using structural equation modeling. The model included concomitant measurements of ecosystem metabolism, hydraulic parameters, and nitrogen concentration. We compared this structural equation model to multiple regression models which included additional biotic, catchment, and riparian variables. The structural equation model explained 79% of the variation in log uptake length (SWtot). Uptake length increased with specific discharge (Q/w) and increasing NO3− concentrations, showing a loss in removal efficiency in streams with high NO3− concentration. Uptake lengths shortened with increasing gross primary production, suggesting autotrophic assimilation dominated NO3− removal. The fraction of catchment area as agriculture and suburban-urban land use weakly predicted NO3− uptake in bivariate regression, and did improve prediction in a set of multiple regression models. Adding land use to the structural equation model showed that land use indirectly affected NO3− uptake lengths via directly increasing both gross primary production and NO3− concentration. Gross primary production shortened SWtot, while increasing NO3− lengthened SWtot resulting in no net effect of land use on NO3− removal.Publication Sediment nitrate manipulation using porewater equilibrators reveals potential for N and S coupling in freshwaters(Inter Research, 2009-02-24) Payne, E. K.; Burgin, Amy J.; Hamilton, Stephen K.Anthropogenic nitrogen (N) loading to agricultural and populated landscapes has resulted in elevated nitrate (NO3–) concentrations in ground water, streams and rivers, ultimately causing problems in coastal marine environments such as eutrophication, hypoxia and harmful algal blooms. Nitrate removal along hydrologic flow paths through landscapes intercepts much of the N before it reaches coastal zones. We used traditional porewater equilibrators in a novel way to add nitrate to the sediment porewater of 8 wetlands in southwestern Michigan. Nitrate losses and changes in porewater chemistry were examined to elucidate N removal processes, with particular focus on the potential coupling of bacterial sulfur (S) oxidation to (1) dissimilatory nitrate reduction to ammonium (DNRA) and (2) denitrification. We hypothesized that, if S oxidizers utilized the added nitrate, porewater sulfide concentrations should decrease and sulfate concentrations should increase. Additionally, if the nitrate is used in DNRA, ammonium concentrations should increase as well. Nitrate additions caused decreases in dissolved hydrogen sulfide and increases in sulfate relative to controls at all sites. Ammonium also tended to increase, though the response was less consistent due to a high background ammonium pool. These results provide evidence that microbial S transformations may play an important role in nitrate removal in these freshwater wetland sediments.Publication Restarting the conversation: challenges at the interface between ecology and society(Ecological Society of America, 2010-08-01) Groffman, Peter M.; Stylinski, Cathlyn; Nisbet, Matthew C.; Duarte, Carlos M.; Jordan, Rebecca; Burgin, Amy J.; Previtali, M. Andrea; Coloso, JamesThe exchange of information between researchers, resource managers, decision makers, and the general public has long been recognized as a critical need in environmental science. We examine the challenges in using ecological knowledge to inform society and to change societal actions, and identify a set of options and strategies to enhance this exchange. Our objectives are to provide background information on societal knowledge and interest in science and environmental issues, to describe how different components of society obtain information and develop their interests and values, and to present a framework for evaluating and improving communication between science and society. Our analysis strongly suggests that the interface between science and society can only be improved with renewed dedication to public outreach and a wholesale reconsideration of the way that scientists communicate with society. Ecologists need to adopt new models of engagement with their audiences, frame their results in ways that are more meaningful to these audiences, and use new communication tools, capable of reaching large and diverse target groups.Publication Beyond carbon and nitrogen: how the microbial energy economy couples elemental cycles in diverse ecosystems(Ecological Society of America, 2011-02-01) Burgin, Amy J.; Yang, Wendy H.; Hamilton, Stephen K.; Silver, Whendee L.Microbial metabolism couples elemental reactions, driving biogeochemical cycles. Assimilatory coupling of elemental cycles, such as the carbon (C), nitrogen (N), and phosphorus cycles, occurs when these elements are incorporated into biomass or released through its decomposition. In addition, many microbes are capable of dissimilatory coupling, catalyzing energy-releasing reactions linked to transformations in the oxidation state of elements, and releasing the transformed elements to the environment. Different inorganic elements provide varying amounts of energy yield, and the interaction of these processes creates a microbial energy economy. Dissimilatory reactions involving C, N, iron, and sulfur provide particularly important examples where microbially mediated oxidation–reduction (redox) transformations affect nutrient availability for net primary production, greenhouse-gas emissions, levels of contaminants and natural toxic factors, and other ecosystem dynamics. Recent discoveries of previously unrecognized microbial dissimilatory processes are leading to reevaluation of traditional perceptions of biogeochemical cycles.