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Faculty Publications

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Articles 151 - 180 of 383

Full-Text Articles in Earth Sciences

Beyond Static Benchmarking: Using Experimental Manipulations To Evaluate Land Model Assumptions, William R. Wieder, David M. Lawrence, Rosie A. Fisher, Gordon B. Bonan, Susan J. Cheng, Christine L. Goodale, A. Stuart Grandy, Charles D. Koven, Danica L. Lombardozzi, Keith W. Oleson, R. Quinn Thomas Jun 2019

Beyond Static Benchmarking: Using Experimental Manipulations To Evaluate Land Model Assumptions, William R. Wieder, David M. Lawrence, Rosie A. Fisher, Gordon B. Bonan, Susan J. Cheng, Christine L. Goodale, A. Stuart Grandy, Charles D. Koven, Danica L. Lombardozzi, Keith W. Oleson, R. Quinn Thomas

Faculty Publications

Land models are often used to simulate terrestrial responses to future environmental changes, but these models are not commonly evaluated with data from experimental manipulations. Results from experimental manipulations can identify and evaluate model assumptions that are consistent with appropriate ecosystem responses to future environmental change. We conducted simulations using three coupled carbon-nitrogen versions of the Community Land Model (CLM, versions 4, 4.5, and—the newly developed—5), and compared the simulated response to nitrogen (N) and atmospheric carbon dioxide (CO2) enrichment with meta-analyses of observations from similar experimental manipulations. In control simulations, successive versions of CLM showed a poleward increase in …

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Structural Control Of Mesic Vegetation Communities Within The Owl And Bear Creek Watersheds, Fort Hood Military Installation, Texas, Melinda S. Faulkner, Matthew Mcbroom, Kenneth W. Farrish, Kevin Stafford Jun 2019

Structural Control Of Mesic Vegetation Communities Within The Owl And Bear Creek Watersheds, Fort Hood Military Installation, Texas, Melinda S. Faulkner, Matthew Mcbroom, Kenneth W. Farrish, Kevin Stafford

Faculty Publications

The Fort Hood Military Installation is a karst landscape, dominated by Lower Cretaceous carbonates of the Trinity and Fredericksburg groups. The study area is the northeastern peninsula known as the Owl Mountain Province, utilized by the U.S. Army for troop maneuvers and training. The geomorphic evolution of the province has been controlled by the structural development of incised canyons in the Owl and Bear creek watersheds, following the deformational trend of the Balcones/Ouachita fault system and the transverse Belton High-Central Texas Reef Trend. These trends control cave development in the subsurface, karst manifestations at the surface, joints in outcrop, stream …

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Mercury Cycling In The North Pacific Subtropical Gyre As Revealed By Mercury Stable Isotope Ratios, Laura C. Motta, Joel D. Blum, Marcus W. Johnson, Blaire P. Umhau, Brian N. Popp, Spencer J. Washburn, Jeffrey C. Drazen, Claudia R. Benitez-Nelson, Cecelia C. S. Hannides, Hilary G. Close, Carl H. Lamborg May 2019

Mercury Cycling In The North Pacific Subtropical Gyre As Revealed By Mercury Stable Isotope Ratios, Laura C. Motta, Joel D. Blum, Marcus W. Johnson, Blaire P. Umhau, Brian N. Popp, Spencer J. Washburn, Jeffrey C. Drazen, Claudia R. Benitez-Nelson, Cecelia C. S. Hannides, Hilary G. Close, Carl H. Lamborg

Faculty Publications

The oceans are an important global reservoir for mercury (Hg), and marine fish consumption is the dominant human exposure pathway for its toxic methylated form. A more thorough understanding of the global biogeochemical cycle of Hg requires additional information on the mechanisms that control Hg cycling in pelagic marine waters. In this study, Hg isotope ratios and total Hg concentrations are used to explore Hg biogeochemistry in oligotrophic marine environments north of Hawaii. We present the first measurements of the vertical water column distribution of Hg concentrations and the Hg isotopic composition in precipitation, marine particles, and zooplankton near Station …

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Managing Agroecosystems For Soil Microbial Carbon Use Efficiency: Ecological Unknowns, Potential Outcomes, And A Path Forward, Cynthia M. Kallenbach, Matthew D. Wallenstein, Meagan E. Schipanksi, A. Stuart Grandy May 2019

Managing Agroecosystems For Soil Microbial Carbon Use Efficiency: Ecological Unknowns, Potential Outcomes, And A Path Forward, Cynthia M. Kallenbach, Matthew D. Wallenstein, Meagan E. Schipanksi, A. Stuart Grandy

Faculty Publications

Agricultural systems are increasingly managed for improving soil carbon (C) accumulation. However, there are limits to C returns in agricultural systems that constrain soil C accumulation capacity. Increasing the efficiency of how soil microbes process C is gaining interest as an important management strategy for increasing soil C and is a key feature of soil C dynamics in many new microbial-explicit models. A higher microbial C use efficiency (CUE) may increase C storage while reducing C system losses and is a fundamental trait affecting community assembly dynamics and nutrient cycling. However, the numerous ecological unknowns influencing CUE limit our ability …

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Substrate Quality And Concentration Control Decomposition And Microbial Strategies In A Model Soil System, Jorg Schnecker, Timothy Bowles, Erik A. Hobbie, Richard G. Smith, A. Stuart Grandy May 2019

Substrate Quality And Concentration Control Decomposition And Microbial Strategies In A Model Soil System, Jorg Schnecker, Timothy Bowles, Erik A. Hobbie, Richard G. Smith, A. Stuart Grandy

Faculty Publications

Soil carbon models typically scale decomposition linearly with soil carbon (C) concentration, but this linear relationship has not been experimentally verified. Here we investigated the underlying biogeochemical mechanisms controlling the relationships between soil C concentration and decomposition rates. We incubated a soil/sand mixture with increasing amounts of finely ground plant residue in the laboratory at constant temperature and moisture for 63 days. The plant residues were rye (Secale cereale, C/N ratio of 23) and wheat straw (Triticum spp., C/N ratio of 109) at seven soil C concentrations ranging from 0.38 to 2.99%. We measured soil respiration, dissolved organic carbon (DOC) …

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Floodwater Impact On Galveston Bay Phytoplankton Taxonomy, Pigment Composition And Photo-Physiological State Following Hurricane Harvey From Field And Ocean Color (Sentinel-3a Olci) Observations, Eurico D'Sa May 2019

Floodwater Impact On Galveston Bay Phytoplankton Taxonomy, Pigment Composition And Photo-Physiological State Following Hurricane Harvey From Field And Ocean Color (Sentinel-3a Olci) Observations, Eurico D'Sa

Faculty Publications

Phytoplankton taxonomy, pigment composition and photo-physiological state were studied in Galveston Bay (GB), Texas (USA), following the extreme flooding associated with Hurricane Harvey (25-29 August 2017) using field and satellite ocean color observations. The percentage of chlorophyll a (Chl a) in different phytoplankton groups was determined from a semi-analytical IOP (inherent optical property) inversion algorithm. The IOP inversion algorithm revealed the dominance of freshwater species (diatom, cyanobacteria and green algae) in the bay following the hurricane passage (29 September 2017) under low salinity conditions associated with the discharge of floodwaters into GB. Two months after the hurricane (29-30 October 2017), …

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Short-Term Effect Of Simulated Salt Marsh Restoration By Sand-Amendment On Sediment Bacterial Communities, François Thomas, James T. Morris, Cathleen Wigand, Stefan M. Sievert Apr 2019

Short-Term Effect Of Simulated Salt Marsh Restoration By Sand-Amendment On Sediment Bacterial Communities, François Thomas, James T. Morris, Cathleen Wigand, Stefan M. Sievert

Faculty Publications

Coastal climate adaptation strategies are needed to build salt marsh resiliency and maintain critical ecosystem services in response to impacts caused by climate change. Although resident microbial communities perform crucial biogeochemical cycles for salt marsh functioning, their response to restoration practices is still understudied. One promising restoration strategy is the placement of sand or sediment onto the marsh platform to increase marsh resiliency. A previous study examined the above- and below-ground structure, soil carbon dioxide emissions, and pore water constituents in Spartina alterniflora-vegetated natural marsh sediments and sand-amended sediments at varying inundation regimes. Here, we analyzed samples from the …

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Growth Kinetics, Carbon Isotope Fractionation, And Gene Expression In The Hyperthermophile Methanocaldococcus Jannaschii During Hydrogen-Limited Growth And Interspecies Hydrogen Transfer, Begüm D. Topçuog˘ Lu, Cem Meydan, Tran B. Nguyen, Susan Q. Lang, James F. Holden Apr 2019

Growth Kinetics, Carbon Isotope Fractionation, And Gene Expression In The Hyperthermophile Methanocaldococcus Jannaschii During Hydrogen-Limited Growth And Interspecies Hydrogen Transfer, Begüm D. Topçuog˘ Lu, Cem Meydan, Tran B. Nguyen, Susan Q. Lang, James F. Holden

Faculty Publications

Hyperthermophilic methanogens are often H2 limited in hot subseafloor environments, and their survival may be due in part to physiological adaptations to low H2 conditions and interspecies H2 transfer. The hyperthermophilic methanogen Methanocaldococcus jannaschii was grown in monoculture at high (80 to 83 M) and low (15 to 27 M) aqueous H2 concentrations and in coculture with the hyperthermophilic H2 producer Thermococcus paralvinellae. The purpose was to measure changes in growth and CH4 production kinetics, CH4 fractionation, and gene expression in M. jannaschii with changes in H2 flux. Growth and cell-specific CH4 production rates of M. jannaschii decreased with decreasing …

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Sedimentary Budget Of The Northwest Sub-Basin, South China Sea: Controlling Factors And Geological Implications, Peter D. Clift Apr 2019

Sedimentary Budget Of The Northwest Sub-Basin, South China Sea: Controlling Factors And Geological Implications, Peter D. Clift

Faculty Publications

We calculated the sedimentary budget of the Northwest Sub-basin (NWSB), South China Sea for different geological times based on interpretations of four multichannel seismic profiles across the basin with constraints from International Ocean Discovery Program (IODP) Expeditions 367 and 368 drilling results. Sedimentation was generally dominated by regional tectonic events and climate change, but complicated by local tectonic events and geographic position, which resulted in a specific sedimentary budget in the NWSB compared with other marginal basins and the Southwest Sub-basin. The sedimentation rate was relatively low following the opening of the NWSB but increased gradually during the Middle Miocene, …

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Differentiation Of Surface Water And Groundwater In A Karst System Using Anthropogenic Signatures, Joe Honings Apr 2019

Differentiation Of Surface Water And Groundwater In A Karst System Using Anthropogenic Signatures, Joe Honings

Faculty Publications

Surface water-groundwater interaction within a karstic system enhances contaminant transport, making karst aquifers susceptible to anthropogenic practices. Contaminated waters related to agricultural and animal husbandry in northwestern Illinois (USA) prompted this investigation. Six streams and five springs were sampled for 16 parameters to assess anthropogenic influences. Statistical analyses revealed differences in 13 of 16 parameters between the stream and spring waters. Rock-water interaction was identified as the dominant mechanism defining the chemistry for both waters, which were classified as Ca-Mg HCO3. Elevated nitrate as nitrogen (NO3-N), chloride (Cl-), sodium, and potassium concentrations indicate that human activities have influenced the quality …

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Soil Macroinvertebrate Presence Alters Microbial Community Composition And Activity In The Rhizosphere, Natalie Bray, Jenny Kao-Kniffin, Serita D. Frey, Timothy Fahey, Kyle Wickings Feb 2019

Soil Macroinvertebrate Presence Alters Microbial Community Composition And Activity In The Rhizosphere, Natalie Bray, Jenny Kao-Kniffin, Serita D. Frey, Timothy Fahey, Kyle Wickings

Faculty Publications

Soil Macroinvertebrate Presence Alters Microbial Community Composition and Activity in the Rhizosphere

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In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann Feb 2019

In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann

Faculty Publications

The dolomitization and diagenetic history of Ordovician carbonates of southern Wisconsin is complex. Previous studies attributed dolomitization to various diagenetic factors and environments. In this study, high-resolution, in situ laser ablation inductively coupled mass spectrometry analysis of rare earth element patterns of dolomite was used to assess the diagenetic fluids responsible for dolomitization of the Ordovician Decorah Formation. Integrated geochemical data and petrographic evidence suggest that the dolostones are formed in two different diagenetic realms: shallow burial and hydrothermal. Shallow burial dolomites exhibit three distinct rare earth element patterns. Dolomite from the middle portion of the Guttenberg Member exhibits light …

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Restoration Of Soil Microbial Function Following Degradation On Department Of Defense Lands: Mediating Biological Invasions In A Global Change Context, Kristina Stinson, Serita D. Frey Jan 2019

Restoration Of Soil Microbial Function Following Degradation On Department Of Defense Lands: Mediating Biological Invasions In A Global Change Context, Kristina Stinson, Serita D. Frey

Faculty Publications

This project was designed to better understand the roles of soil biota in 1 mediating native species-NIS interactions and 2 facilitating the recovery of degraded ecosystems. The associated Research Needs were listed as follows 1. To quantify the functional diversity of soil biota and the role of key taxa in maintaining desired functional ecosystem attributes 2. To identify processes by which desired soil properties and associated soil biotic communities are degraded by NIS invasion and test potential mechanisms to restore them 3. To examine the role of disturbance in determining the functional attributes of the soil community 4. To test …

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Short Communication: The Topographic Analysis Kit (Tak) For Topotoolbox, Adam M. Fortes Jan 2019

Short Communication: The Topographic Analysis Kit (Tak) For Topotoolbox, Adam M. Fortes

Faculty Publications

Quantitative analysis of digital topographic data is an increasingly important part of many studies in the geosciences. Initially, performing these analyses was a niche endeavor, requiring detailed domain knowledge and programming skills, but increasingly broad, flexible, open-source code bases have been developed to increasingly democratize topographic analysis. However, many of these analyses still require specific computing environments and/or moderate levels of knowledge of both the relevant programming language and the correct way to take these fundamental building blocks and conduct an efficient and effective topographic analysis. To partially address this, we have written the Topographic Analysis Kit (TAK), which leverages …

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The Microbiome Stress Project: Toward A Global Meta-Analysis Of Environmental Stressors And Their Effects On Microbial Communities, Jennifer D. Rocca, Marie Simonin, Joanna R. Blaszczak, Jessica G. Ernakovich, Sean M. Gibbons, Firas S. Midani, Alex D. Washburne Jan 2019

The Microbiome Stress Project: Toward A Global Meta-Analysis Of Environmental Stressors And Their Effects On Microbial Communities, Jennifer D. Rocca, Marie Simonin, Joanna R. Blaszczak, Jessica G. Ernakovich, Sean M. Gibbons, Firas S. Midani, Alex D. Washburne

Faculty Publications

Microbial community structure is highly sensitive to natural (e.g., drought, temperature, fire) and anthropogenic (e.g., heavy metal exposure, land-use change) stressors. However, despite an immense amount of data generated, systematic, cross-environment analyses of microbiome responses to multiple disturbances are lacking. Here, we present the Microbiome Stress Project, an open-access database of environmental and host-associated 16S rRNA amplicon sequencing studies collected to facilitate cross-study analyses of microbiome responses to stressors. This database will comprise published and unpublished datasets re-processed from the raw sequences into exact sequence variants using our standardized computational pipeline. Our database will provide insight into general response patterns …

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Correlates Of Snake Entanglement In Erosion Control Blankets, Sarah E. Ebert, Kasey L. Jobe, Christopher M. Schalk, Daniel Saenz, Cory K. Adams, Christopher E. Comer Jan 2019

Correlates Of Snake Entanglement In Erosion Control Blankets, Sarah E. Ebert, Kasey L. Jobe, Christopher M. Schalk, Daniel Saenz, Cory K. Adams, Christopher E. Comer

Faculty Publications

In road construction projects across the United States, erosion control methods (e.g., erosion control blankets [ECBs]), are mandated to stimulate seedbed regeneration and prevent soil loss. Previous reports have suggested that snakes are vulnerable to entanglement in ECBs. We conducted a literature review, field surveys, and an entanglement experiment to examine what factors increase a snake’s risk of ECB entanglement. Our literature review produced reports of 175 reptiles entangled in mesh products, 89.1% of which were snakes, with 43.6% of snake entanglements occurring in erosion control products. During our field surveys, we found 10 entangled snakes (n = 2 alive; …

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Crossed Tracks: Mesolimulus, Archaeopteryx, And The Nature Of Fossils, Leonard Finkelman Jan 2019

Crossed Tracks: Mesolimulus, Archaeopteryx, And The Nature Of Fossils, Leonard Finkelman

Faculty Publications

Organisms leave a variety of traces in the fossil record. Among these traces, vertebrate and invertebrate paleontologists conventionally recognize a distinction between the remains of an organism’s phenotype (body fossils) and the remains of an organism’s life activities (trace fossils). The same convention recognizes body fossils as biological structures and trace fossils as geological objects. This convention explains some curious practices in the classification, as with the distinction between taxa for trace fossils and for tracemakers. I consider the distinction between “parallel taxonomies,” or parataxonomies, which privileges some kinds of fossil taxa as “natural” and others as “artificial.” The motivations …

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Betting & Hierarchy In Paleontology, Leonard Finkelman Jan 2019

Betting & Hierarchy In Paleontology, Leonard Finkelman

Faculty Publications

In his Rock, Bone, and Ruin: An Optimist’s Guide to the Historical Sciences, Adrian Currie argues that historical scientists should be optimistic about success in reconstructing the past on the basis of future research. This optimism follows in part from examples of success in paleontology. I argue that paleontologists’ success in these cases is underwritten by the hierarchical nature of biological information: extinct organisms have extant analogues at various levels of taxonomic, ecological, and physiological hierarchies, and paleontologists are adept at exploiting analogies within one informational hierarchy to infer information in another. On this account, fossils serve the role …

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Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen Jan 2019

Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen

Faculty Publications

Building on the synthesis of carbon reservoirs in Earth's subsurface, this chapter focuses on the forms, cycling, and fate of the carbon supporting microbial life in the terrestrial and marine subsurface. As the subsurface is estimated to host a vast reservoir of life on Earth, identifying the carbon compounds that life uses for energy and growth is key to understanding ecosystem functioning in the past and at present, and also for extrapolating these findings to the search for life in the universe. This chapter highlights advances in quantifying small carbon compounds, measuring rates of carbon turnover, and the fate of …

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Clarifying The Interpretation Of Carbon Use Efficiency In Soil Through Methods Comparison, Kevin M. Geyer, Paul Dijkstra, Robert Sinsabaugh, Serita D. Frey Jan 2019

Clarifying The Interpretation Of Carbon Use Efficiency In Soil Through Methods Comparison, Kevin M. Geyer, Paul Dijkstra, Robert Sinsabaugh, Serita D. Frey

Faculty Publications

Accurate estimates of microbial carbon use efficiency (CUE) are required to predict how global change will impact microbially-mediated ecosystem functions such as organic matter decomposition. Multiple approaches are currently used to quantify CUE but the extent to which estimates reflect methodological variability is unknown. This limits our ability to apply or cross-compare published CUE values. Here we evaluated the performance of five methods in a single soil under standard conditions. The microbial response to three substrate amendment rates (0.0, 0.05, and 2.0 mg glucose-C g−1 soil) was examined using: 13C and 18O isotope tracing approaches which estimate CUE based on …

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Remains Of The 19th Century: Deep Storage Of Contaminated Hydraulic Mining Sediment Along The Lower Yuba River, California, Tyler Nakamura, Michael Bliss Singer, Emmanuel Gabet Nov 2018

Remains Of The 19th Century: Deep Storage Of Contaminated Hydraulic Mining Sediment Along The Lower Yuba River, California, Tyler Nakamura, Michael Bliss Singer, Emmanuel Gabet

Faculty Publications

Since the onset of hydraulic gold mining in California’s Sierra Nevada foothills in 1852, the environmental damage caused by displacement and storage of hydraulic mining sediment (HMS) has been a significant ecological problem downstream. Large volumes of mercury-laden HMS from the Yuba River watershed were deposited within the river corridor, creating the anthropogenic Yuba Fan. However, there are outstanding uncertainties about how much HMS is still contained within this fan. To quantify the deep storage of HMS in the Yuba Fan, we analyzed mercury concentrations of sediment samples collected from borings and outcrops at multiple depths. The mercury concentrations served …

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A Time Series Of Water Column Distributions And Sinking Particle Flux Of Pseudo-Nitzschia And Domoic Acid In The Santa Barbara Basin, California, Blaire P. Umhau, Claudia R. Benitez-Nelson, Clarissa R. Anderson, Kelly Mccabe, Christopher Burrell Nov 2018

A Time Series Of Water Column Distributions And Sinking Particle Flux Of Pseudo-Nitzschia And Domoic Acid In The Santa Barbara Basin, California, Blaire P. Umhau, Claudia R. Benitez-Nelson, Clarissa R. Anderson, Kelly Mccabe, Christopher Burrell

Faculty Publications

Water column bulk Pseudo-nitzschia abundance and the dissolved and particulate domoic acid (DA) concentrations were measured in the Santa Barbara Basin (SBB), California from 2009–2013 and compared to bulk Pseudo-nitzschia cell abundance and DA concentrations and fluxes in sediment traps moored at 147 m and 509 m. Pseudo-nitzschia abundance throughout the study period was spatially and temporally heterogeneous (L−1 to 3.8 × 106 cells L−1, avg. 2 × 105 ± 5 × 105 cells L−1) and did not correspond with upwelling conditions or the total DA (tDA) concentration, which was also spatially …

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Reduced Carbon Use Efficiency And Increased Microbial Turnover With Soil Warming, Jianwei Li, Gangsheng Wang, Melanie A. Mayes, Steven D. Allison, Serita D. Frey, Zheng Shi, Xiao-Ming Hu, Yiqi Luo, Jerry M. Melillo Nov 2018

Reduced Carbon Use Efficiency And Increased Microbial Turnover With Soil Warming, Jianwei Li, Gangsheng Wang, Melanie A. Mayes, Steven D. Allison, Serita D. Frey, Zheng Shi, Xiao-Ming Hu, Yiqi Luo, Jerry M. Melillo

Faculty Publications

Global soil carbon (C) stocks are expected to decline with warming, and changes in microbial processes are key to this projection. However, warming responses of critical microbial parameters such as carbon use efficiency (CUE) and biomass turnover (rB) are not well understood. Here, we determine these parameters using a probabilistic inversion approach that integrates a microbial-enzyme model with 22 years of carbon cycling measurements at Harvard Forest. We find that increasing temperature reduces CUE but increases rB, and that two decades of soil warming increases the temperature sensitivities of CUE and rB. These temperature sensitivities, which are derived from decades-long …

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Using Satellite Remote Sensing To Study The Impact Of Climate And Anthropogenic Changes In The Mesopotamian Marshlands, Iraq, Reyadh Albarakat, Venkat Lakshmi, Compton J. Tucker Sep 2018

Using Satellite Remote Sensing To Study The Impact Of Climate And Anthropogenic Changes In The Mesopotamian Marshlands, Iraq, Reyadh Albarakat, Venkat Lakshmi, Compton J. Tucker

Faculty Publications

The Iraqi Marshes in Southern Iraq are considered one of the most important wetlands in the world. From 1982 to the present, their area has varied between 10,500 km2 and 20,000 km2. The marshes support a variety of plants, such as reeds and papyrus, and are home to many species of birds. These marshes are Al-Hammar, Central or Al-Amarah, and Al-Huwaiza. Freshwater supplies to the marshes come from the Tigris and Euphrates rivers in Iraq and from the Karkha River from Iran. For this analysis, we used the Land Long-Term Data Record Version 5 (LTDR V5) Normalized …

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Serpentinization: Connecting Geochemistry, Ancient Metabolism And Industrial Hydrogenation, Martina Preiner, Joana C. Xavier, Fliipa L. Sousa, Verena Zimorski, Anna Neubeck, Susan Q. Lang, H. Chris Greenwell, Karl Kleinermanns, Harun Tüysüz, Tom M. Mccollom, Nils G. Holm, William F. Martin Sep 2018

Serpentinization: Connecting Geochemistry, Ancient Metabolism And Industrial Hydrogenation, Martina Preiner, Joana C. Xavier, Fliipa L. Sousa, Verena Zimorski, Anna Neubeck, Susan Q. Lang, H. Chris Greenwell, Karl Kleinermanns, Harun Tüysüz, Tom M. Mccollom, Nils G. Holm, William F. Martin

Faculty Publications

Rock–water–carbon interactions germane to serpentinization in hydrothermal vents have occurred for over 4 billion years, ever since there was liquid water on Earth. Serpentinization converts iron(II) containing minerals and water to magnetite (Fe3O4) plus H2. The hydrogen can generate native metals such as awaruite (Ni3Fe), a common serpentinization product. Awaruite catalyzes the synthesis of methane from H2 and CO2 under hydrothermal conditions. Native iron and nickel catalyze the synthesis of formate, methanol, acetate, and pyruvate—intermediates of the acetyl-CoA pathway, the most ancient pathway of CO2 fixation. Carbon monoxide dehydrogenase …

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Guidelines And Considerations For Designing Field Experiments Simulating Precipitation Extremes In Forest Ecosystems, Heidi Asbjornsen, John L. Campbell, Katie A. Jennings, Matthew A. Vadeboncoeur, Cameron Mcintire, Pamela H. Templer, Richard P. Phillips, Taryn L. Bauerle, Michael C. Dietze, Serita D. Frey, Peter M. Groffman, Rosella Guerrieri, Paul J. Hanson, Eric P. Kelsey, Alan K. Knapp, Nathan G. Mcdowell, Patrick Meir, Kimberly A. Novick, Scott V. Ollinger, Will T. Pockman, Paul G. Schaberg, Stan D. Wullschleger, Melinda D. Smith, Lindsey E. Rustad Sep 2018

Guidelines And Considerations For Designing Field Experiments Simulating Precipitation Extremes In Forest Ecosystems, Heidi Asbjornsen, John L. Campbell, Katie A. Jennings, Matthew A. Vadeboncoeur, Cameron Mcintire, Pamela H. Templer, Richard P. Phillips, Taryn L. Bauerle, Michael C. Dietze, Serita D. Frey, Peter M. Groffman, Rosella Guerrieri, Paul J. Hanson, Eric P. Kelsey, Alan K. Knapp, Nathan G. Mcdowell, Patrick Meir, Kimberly A. Novick, Scott V. Ollinger, Will T. Pockman, Paul G. Schaberg, Stan D. Wullschleger, Melinda D. Smith, Lindsey E. Rustad

Faculty Publications

Precipitation regimes are changing in response to climate change, yet understanding of how forest ecosystems respond to extreme droughts and pluvials remains incomplete. As future precipitation extremes will likely fall outside the range of historical variability, precipitation manipulation experiments (PMEs) are critical to advancing knowledge about potential ecosystem responses. However, few PMEs have been conducted in forests compared to short-statured ecosystems, and forest PMEs have unique design requirements and constraints. Moreover, past forest PMEs have lacked coordination, limiting cross-site comparisons. Here, we review and synthesize approaches, challenges, and opportunities for conducting PMEs in forests, with the goal of guiding design …

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Cover Crops May Cause Winter Warming In Snow-Covered Regions, Danica L. Lombardozzi, Gordon B. Bonan Sep 2018

Cover Crops May Cause Winter Warming In Snow-Covered Regions, Danica L. Lombardozzi, Gordon B. Bonan

Faculty Publications

Cover crops, grown between cash crops when soil is fallow, are a management strategy that may help mitigate climate change. The biogeochemical effects of cover crops are well documented, as they provide numerous localized benefits to farmers. We test potential biogeophysical climate impacts of idealized cover crop scenarios by assuming that cover crops are planted offseason in all crop regions throughout North America. Our results suggest that planting cover crops increases wintertime temperature up to 3 °C in central North America by decreasing albedo in regions with variable snowpack. Cover crops with higher leaf area indices increase temperature more by …

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Little Lasting Impact Of The Paleocene-Eocene Thermal Maximum On Shallow Marine Molluscan Faunas, Linda Ivany, Carlie Pietsch, John Handley, Rowan Lockwood, Warren Allmon, Jocelyn Sessa Sep 2018

Little Lasting Impact Of The Paleocene-Eocene Thermal Maximum On Shallow Marine Molluscan Faunas, Linda Ivany, Carlie Pietsch, John Handley, Rowan Lockwood, Warren Allmon, Jocelyn Sessa

Faculty Publications

Global warming, acidification, and oxygen stress at the Paleocene-Eocene Thermal Maximum (PETM) are associated with severe extinction in the deep sea and major biogeographic and ecologic changes in planktonic and terrestrial ecosystems, yet impacts on shallow marine macrofaunas are obscured by the incompleteness of shelf sections. We analyze mollusk assemblages bracketing (but not including) the PETM and find few notable lasting impacts on diversity, turnover, functional ecology, body size, or life history of important clades. Infaunal and chemosymbiotic taxa become more common, and body size and abundance drop in one clade, consistent with hypoxia-driven selection, but within-clade changes are not …

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Responses Of Non-Native Earthworms To Experimental Eradication Of Garlic Mustard And Implications For Native Vegetation, Kristina A. Stinson, Serita D. Frey, M. R. Jackson, E. Coates-Connor, Mark A. Anthony, K. Martinez Jul 2018

Responses Of Non-Native Earthworms To Experimental Eradication Of Garlic Mustard And Implications For Native Vegetation, Kristina A. Stinson, Serita D. Frey, M. R. Jackson, E. Coates-Connor, Mark A. Anthony, K. Martinez

Faculty Publications

Recent studies in invasion biology suggest that positive feedback among two or more introduced organisms facilitate establishment within a new range and drive changes in native plant communities. Here, we experimentally tested for relationships between native plants and two non-native organisms invading forest habitats in North America: garlic mustard (Alliaria petiolata, Brassicaceae) and earthworms. In two forested sites, we compared understory vegetation and earthworm biomass in plots where garlic mustard was removed for three years, plots without garlic mustard invasion, and plots invaded by garlic mustard that was not removed. Earthworm biomass was highest in the plots with garlic mustard, …

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Litter Identity Affects Assimilation Of Carbon And Nitrogen By A Shredding Caddisfly, Adam C. Siders, Zacchaeus G. Compson, Bruce A. Hungate, Paul Dijkstra, George W. Koch, Adam S. Wymore, A. Stuart Grandy, Jane C. Marks Jul 2018

Litter Identity Affects Assimilation Of Carbon And Nitrogen By A Shredding Caddisfly, Adam C. Siders, Zacchaeus G. Compson, Bruce A. Hungate, Paul Dijkstra, George W. Koch, Adam S. Wymore, A. Stuart Grandy, Jane C. Marks

Faculty Publications

Ecologists often equate litter quality with decomposition rate. In soil and sediments, litter that is rapidly decomposed by microbes often has low concentrations of tannin and lignin and low C:N ratios. Do these same traits also favor element transfer to higher trophic levels in streams, where many insects depend on litter as their primary food source? We test the hypothesis that slow decomposition rates promote element transfer from litter to insects, whereas rapid decomposition favors microbes. We measured carbon and nitrogen fluxes from four plant species to a leaf-shredding caddisfly using isotopically labeled litter. Caddisflies assimilated a higher percentage of …

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