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Faculty Publications

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Articles 61 - 90 of 383

Full-Text Articles in Earth Sciences

Initial Soil Conditions Outweigh Management In A Cool-Season Dairy Farm's Carbon Sequestration Potential, Kyle A. Arndt, Eleanor E. Campbell, Chris D. Dorich, A. Stuart Grandy, Timothy S. Griffin, Peter Ingraham, Apryl L. Perry, Ruth K. Varner, Alexandra R. Contosta Feb 2022

Initial Soil Conditions Outweigh Management In A Cool-Season Dairy Farm's Carbon Sequestration Potential, Kyle A. Arndt, Eleanor E. Campbell, Chris D. Dorich, A. Stuart Grandy, Timothy S. Griffin, Peter Ingraham, Apryl L. Perry, Ruth K. Varner, Alexandra R. Contosta

Faculty Publications

Pastures and rangelands are a dominant portion of global agricultural land and have the potential to sequester carbon (C) in soils, mitigating climate change. Management intensive grazing (MIG), or high density grazing with rotations through paddocks with long rest periods, has been highlighted as a method of enhancing soil C in pastures by increasing forage production. However, few studies have examined the soil C storage potential of pastures under MIG in the northeastern United States, where the dairy industry comprises a large portion of agricultural use and the regional agricultural economy. Here we present a 12-year study conducted in this …

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Microbial Feedbacks On Soil Organic Matter Dynamics Underlying The Legacy Effect Of Diversified Cropping Systems, Maria Mooshammer, A. Stuart Grandy, Francisco Calderon, Steve Culman, Bill Deen, Rhae A. Drijber, Kari Dunfield, Virginia L. Jin, R. Michael Lehman, Shannon L. Osborne, Marty Schmer, Timothy M. Bowles Feb 2022

Microbial Feedbacks On Soil Organic Matter Dynamics Underlying The Legacy Effect Of Diversified Cropping Systems, Maria Mooshammer, A. Stuart Grandy, Francisco Calderon, Steve Culman, Bill Deen, Rhae A. Drijber, Kari Dunfield, Virginia L. Jin, R. Michael Lehman, Shannon L. Osborne, Marty Schmer, Timothy M. Bowles

Faculty Publications

Crop rotations have well-known aboveground and belowground benefits. At regional to continental scales, the unifying mechanisms of how diversified rotations alter soil organic matter (SOM) dynamics have not been demonstrated. We assessed how increasing crop rotational diversity across a soil-climate gradient affected the integrated response of SOM chemistry, microbial community composition, and its enzymatic potential to degrade SOM. Agroecosystems with the same crop rotational diversity (all sampled during the corn phase) shared similarities in molecular SOM patterns with a strong microbial signature, pointing to common transformation processes. Differences in SOM chemistry between rotations were mainly characterized by shifts in microbial …

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Dominance Of Diffusive Methane Emissions From Lowland Headwater Streams Promotes Oxidation And Isotopic Enrichment, Andrew L. Robison, Wilfred M. Wollheim, Clarice R. Perryman, Annie R. Cotter, Jessica E. Mackay, Ruth K. Varner, Paige Clarizia, Jessica G. Ernakovich Jan 2022

Dominance Of Diffusive Methane Emissions From Lowland Headwater Streams Promotes Oxidation And Isotopic Enrichment, Andrew L. Robison, Wilfred M. Wollheim, Clarice R. Perryman, Annie R. Cotter, Jessica E. Mackay, Ruth K. Varner, Paige Clarizia, Jessica G. Ernakovich

Faculty Publications

Inland waters are the largest natural source of methane (CH4) to the atmosphere, yet the contribution from small streams to this flux is not clearly defined. To fully understand CH4 emissions from streams and rivers, we must consider the relative importance of CH4 emission pathways, the prominence of microbially-mediated production and oxidation of CH4, and the isotopic signature of emitted CH4. Here, we construct a complete CH4 emission budgets for four lowland headwater streams by quantifying diffusive CH4 emissions and comparing them to previously published rates of ebullitive emissions. We also examine the isotopic composition of CH4 along with the …

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Reply To Comment: Controls On Turnover Of Marine Dissolved Organic Matter-Testing The Null Hypothesis Of Purely Concentration-Driven Uptake, Yuan Shen, Ronald Benner Jan 2022

Reply To Comment: Controls On Turnover Of Marine Dissolved Organic Matter-Testing The Null Hypothesis Of Purely Concentration-Driven Uptake, Yuan Shen, Ronald Benner

Faculty Publications

Our recent bioassay experiments indicate that molecular properties are a primary control on the microbial utilization of dissolved organic matter in the ocean. This finding is questioned by Lennartz and Dittmar who modeled our experiments and concluded that our observations could be largely explained by concentration-driven uptake independent from molecular properties. We suggest the authors' models are deficient for establishing the relative roles of molecular properties and concentration-driven uptake. Our conclusion is consistent with earlier and recent experimental results and biogeochemical observations, supporting a unified theory with molecular properties as a more prominent control than concentration-driven uptake on marine organic …

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Future Of Winter In Northeastern North America: Climate Indicators Portray Warming And Snow Loss That Will Impact Ecosystems And Communities, Elizabeth Burakowski, Alix Contosta, Danielle Grogan, Sarah Nelson, Sarah Garlick, Nora Casson Jan 2022

Future Of Winter In Northeastern North America: Climate Indicators Portray Warming And Snow Loss That Will Impact Ecosystems And Communities, Elizabeth Burakowski, Alix Contosta, Danielle Grogan, Sarah Nelson, Sarah Garlick, Nora Casson

Faculty Publications

Winters in northeastern North America have warmed faster than summers, with impacts on ecosystems and society. Global climate models (GCMs) indicate that winters will continue to warm and lose snow in the future, but uncertainty remains regarding the magnitude of warming. Here, we project future trends in winter indicators under lower and higher climate-warming scenarios based on emission levels across northeastern North America at a fine spatial scale (1/16°) relevant to climate-related decision making. Under both climate scenarios, winters continue to warm with coincident increases in days above freezing, decreases in days with snow cover, and fewer nights below freezing. …

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Crop Rotational Complexity Affects Plant-Soil Nitrogen Cycling During Water Deficit, Timothy M. Bowles, Andrea Jilling, Karen Moran-Rivera, Jorg Schnecker, A. Stuart Grandy Jan 2022

Crop Rotational Complexity Affects Plant-Soil Nitrogen Cycling During Water Deficit, Timothy M. Bowles, Andrea Jilling, Karen Moran-Rivera, Jorg Schnecker, A. Stuart Grandy

Faculty Publications

One of the biggest environmental challenges facing agriculture is how to both supply and retain nitrogen (N), especially as precipitation becomes more variable with climate change. We used a greenhouse experiment to assess how contrasting histories of crop rotational complexity affect plant-soil-microbe interactions that govern N processes, including during water stress. With higher levels of carbon and N cycling hydrolytic enzymes, higher mineral-associated organic matter N concentrations, and an altered microbial community, soils from the most complex rotation enabled 80% more corn N uptake under two moisture regimes, compared to soil from monoculture corn. Higher levels of plant N likely …

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Testing Xrf Identification Of Marine Washover Sediment Beds In A Coastal Lake In Southeastern Texas, Usa, Harry F. L. Williams, Chelsea E. Beaubouef, Kam-Biu Liu, Nicholas Culligan, Lance Riedlinger Jan 2022

Testing Xrf Identification Of Marine Washover Sediment Beds In A Coastal Lake In Southeastern Texas, Usa, Harry F. L. Williams, Chelsea E. Beaubouef, Kam-Biu Liu, Nicholas Culligan, Lance Riedlinger

Faculty Publications

This study tests the ability of a novel approach to identifying washover beds in coastal lakes. Combined X-Ray Fluorescence (XRF) and cluster analysis was used to identify hurricane washover beds in sediment cores from Clam Lake on the McFaddin National Wildlife Refuge in southeastern Texas. The lake is known to contain washover beds from recent hurricanes, but the washover sediment has similar microfossil, loss-on-ignition and textural characteristics to non-washover sediment and is not readily distinguishable. Sediment cores taken from marshes surrounding the lake do contain visually-recognizable sandy washover beds of Hurricanes Ike, Rita, Carla and Audrey. XRF analysis of these …

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Intercomparison Of Salinity Products In The Beaufort Gyre And Arctic Ocean, Sarah B. Hall, Bulusu Subrahmanyam, James H. Morison Dec 2021

Intercomparison Of Salinity Products In The Beaufort Gyre And Arctic Ocean, Sarah B. Hall, Bulusu Subrahmanyam, James H. Morison

Faculty Publications

Salinity is the primary determinant of the Arctic Ocean’s density structure. Freshwater accumulation and distribution in the Arctic Ocean have varied significantly in recent decades and certainly in the Beaufort Gyre (BG). In this study, we analyze salinity variations in the BG region between 2012 and 2017. We use in situ salinity observations from the Seasonal Ice Zone Reconnaissance Surveys (SIZRS), CTD casts from the Beaufort Gyre Exploration Project (BGP), and the EN4 data to validate and compare with satellite observations from Soil Moisture Active Passive (SMAP), Soil Moisture and Ocean Salinity (SMOS), and Aquarius Optimally Interpolated Sea Surface Salinity …

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Salt Marshes As Groundwater Buffers For Development: A Survey Of South Carolina Salt Marsh Basins, Alicia M. Wilson, Meghan Shanahan, Erik M. Smith Dec 2021

Salt Marshes As Groundwater Buffers For Development: A Survey Of South Carolina Salt Marsh Basins, Alicia M. Wilson, Meghan Shanahan, Erik M. Smith

Faculty Publications

Salt marshes serve as zones of intense groundwater mixing and reaction between freshwater uplands and estuaries. This raises the question of whether the impacts of upland development on nutrient and carbon species can be transmitted through salt marshes via groundwater, or whether salt marshes can buffer estuarine waters from coastal development. We sampled groundwater from fifteen tidal creek basins in South Carolina to test for compositional differences associated with development and marsh width. Groundwater samples from near creekbanks and below freshwater uplands were analyzed for salinity, total dissolved nitrogen and phosphorus, and dissolved organic carbon. Analyses revealed significantly higher TDN …

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Fungal Community And Functional Responses To Soil Warming Are Greater Than For Soil Nitrogen Enrichment, Mark A. Anthony, Melissa A. Knorr, Jessica A. M. Moore, M. Simpson, Serita D. Frey Dec 2021

Fungal Community And Functional Responses To Soil Warming Are Greater Than For Soil Nitrogen Enrichment, Mark A. Anthony, Melissa A. Knorr, Jessica A. M. Moore, M. Simpson, Serita D. Frey

Faculty Publications

Soil fungi are key regulators of forest carbon cycling and their responses to global change have effects that ripple throughout ecosystems. Global changes are expected to push many fungi beyond their environmental niches, but there are relatively few studies involving multiple, simultaneous global change factors. Here, we studied soil fungal diversity, community composition, co-occurrence patterns, and decomposition gene responses to 10 years of soil warming and nitrogen addition, alone and in combination. We specifically examined whether there were fungal community characteristics that could explain changes in soil carbon storage and organic matter chemistry in chronically warmed and fertilized soil. We …

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Assessing Population Exposure To Coastal Flooding Due To Sea Level Rise, Matthew E. Hauer, Dean Hardy, Scott A. Kulp, Valerie Mueller, David J. Wrathall, Peter U. Clark Nov 2021

Assessing Population Exposure To Coastal Flooding Due To Sea Level Rise, Matthew E. Hauer, Dean Hardy, Scott A. Kulp, Valerie Mueller, David J. Wrathall, Peter U. Clark

Faculty Publications

The exposure of populations to sea-level rise (SLR) is a leading indicator assessing the impact of future climate change on coastal regions. SLR exposes coastal populations to a spectrum of impacts with broad spatial and temporal heterogeneity, but exposure assessments often narrowly define the spatial zone of flooding. Here we show how choice of zone results in differential exposure estimates across space and time. Further, we apply a spatio-temporal flood-modeling approach that integrates across these spatial zones to assess the annual probability of population exposure. We apply our model to the coastal United States to demonstrate a more robust assessment …

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Diffusional Fractionation Of Helium Isotopes In Silicate Melts, Haiyang Luo, Bijaya Karki, Dipta B. Ghosh, Huiming Bao Oct 2021

Diffusional Fractionation Of Helium Isotopes In Silicate Melts, Haiyang Luo, Bijaya Karki, Dipta B. Ghosh, Huiming Bao

Faculty Publications

Estimating Helium (He) concentration and isotope composition of the mantle requires quantifying He loss during magma degassing. The knowledge of diffusional He isotope fractionation in silicate melts may be essential to constrain the He loss. Isotopic mass dependence of He diffusion can be empirically expressed as D3He/D4He = (4/3)^β, where D is the diffusivity of a He isotope. However, no studies have reported any β values for He in silicate melts due to technical challenges in both experiments and computations. Here, molecular dynamics simulations based on deep neural network potentials trained by ab initio data …

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The Response Of Airborne Mycobiome To Dust Storms In The Eastern Mediterranean, Xuefeng Peng, Daniela Gat, Adina Paytan, Yinon Rudich Sep 2021

The Response Of Airborne Mycobiome To Dust Storms In The Eastern Mediterranean, Xuefeng Peng, Daniela Gat, Adina Paytan, Yinon Rudich

Faculty Publications

Airborne microbial communities directly impact the health of humans, animals, plants, and receiving ecosystems. While airborne bacterial and fungal communities have been studied by both cultivation-based methods and metabarcoding surveys targeting specific molecular markers, fewer studies have used shotgun metagenomics to study the airborne mycobiome. We analyzed the diversity and relative abundance of fungi in nine airborne metagenomes collected on clear days (“background”) and during dust storms in the Eastern Mediterranean. The negative correlation between the relative abundance of fungal reads and the concentrations of atmospheric particulate matter having an aerodynamic diameter smaller than 10 μm (PM10) indicate that dust …

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Increasing The Spatial And Temporal Impact Of Ecological Research: A Roadmap For Integrating A Novel Terrestrial Process Into An Earth System Model, Emily Kyker-Snowman, Danica L. Lombardozzi, Gordon B. Bonan, Susan J. Cheng, Jeffrey S. Dukes, Serita D. Frey, Elin M. Jacobs, Risa Mcnellis, Joshua M. Rady, Nicholas G. Smith, R. Quinn Thomas, William R. Wieder, A. Stuart Grandy Sep 2021

Increasing The Spatial And Temporal Impact Of Ecological Research: A Roadmap For Integrating A Novel Terrestrial Process Into An Earth System Model, Emily Kyker-Snowman, Danica L. Lombardozzi, Gordon B. Bonan, Susan J. Cheng, Jeffrey S. Dukes, Serita D. Frey, Elin M. Jacobs, Risa Mcnellis, Joshua M. Rady, Nicholas G. Smith, R. Quinn Thomas, William R. Wieder, A. Stuart Grandy

Faculty Publications

Terrestrial ecosystems regulate Earth's climate through water, energy, and biogeochemical transformations. Despite a key role in regulating the Earth system, terrestrial ecology has historically been underrepresented in the Earth system models (ESMs) that are used to understand and project global environmental change. Ecology and Earth system modeling must be integrated for scientists to fully comprehend the role of ecological systems in driving and responding to global change. Ecological insights can improve ESM realism and reduce process uncertainty, while ESMs offer ecologists an opportunity to broadly test ecological theory and increase the impact of their work by scaling concepts through time …

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Patterns And Trends Of Organic Matter Processing And Transport: Insights From The Us Long-Term Ecological Research Network, Tamara K. Harms, Peter M. Groffman, Lihini Aluwihare, Christopher Craft, William R. Wieder, Sarah E. Hobbie, Sara G. Baer, John M. Blair, Serita D. Frey, Christina K. Remucal, Jennifer A. Rudgers, Scott L. Collins, John S. Kominoski, Becky A. Ball, Lter Om Working Group Sep 2021

Patterns And Trends Of Organic Matter Processing And Transport: Insights From The Us Long-Term Ecological Research Network, Tamara K. Harms, Peter M. Groffman, Lihini Aluwihare, Christopher Craft, William R. Wieder, Sarah E. Hobbie, Sara G. Baer, John M. Blair, Serita D. Frey, Christina K. Remucal, Jennifer A. Rudgers, Scott L. Collins, John S. Kominoski, Becky A. Ball, Lter Om Working Group

Faculty Publications

Organic matter (OM) dynamics determine how much carbon is stored in ecosystems, a service that modulates climate. We synthesized research from across the US Long-Term Ecological Research (LTER) Network to assemble a conceptual model of OM dynamics that is consistent with inter-disciplinary perspectives and emphasizes vulnerability of OM pools to disturbance. Guided by this conceptual model, we identified unanticipated patterns and long-term trends in processing and transport of OM emerging from terrestrial, freshwater, wetland, and marine ecosystems. Cross-ecosystem synthesis combined with a survey of researchers revealed several themes: 1) strong effects of climate change on OM dynamics, 2) surprising patterns …

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Moving On Up: Vertical Distribution Shifts In Rocky Reef Fish Species During Climate-Driven Decline In Dissolved Oxygen From 1995 To 2009, Erin L. Meyer-Gutbrod, Li Kui, Mary Nishimoto, Linda Snook, Milton Love Sep 2021

Moving On Up: Vertical Distribution Shifts In Rocky Reef Fish Species During Climate-Driven Decline In Dissolved Oxygen From 1995 To 2009, Erin L. Meyer-Gutbrod, Li Kui, Mary Nishimoto, Linda Snook, Milton Love

Faculty Publications

Anthropogenic climate change has resulted in warming temperatures and reduced oxygen concentrations in the global oceans. Much remains unknown on the impacts of reduced oxygen concentrations on the biology and distribution of marine fishes. In the Southern California Channel Islands, visual fish surveys were conducted frequently in a manned submersible at three rocky reefs between 1995 and 2009. This area is characterized by a steep bathymetric gradient, with the surveyed sites Anacapa Passage, Footprint and Piggy Bank corresponding to depths near 50, 150 and 300 m. Poisson models were developed for each fish species observed consistently in this network of …

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Ocean Regime Shift Is Driving Collapse Of The North Atlantic Right Whale Population, Erin L. Meyer-Gutbrod, Charles H. Greene, Kimberley T.A. Davies, David G. Johns Aug 2021

Ocean Regime Shift Is Driving Collapse Of The North Atlantic Right Whale Population, Erin L. Meyer-Gutbrod, Charles H. Greene, Kimberley T.A. Davies, David G. Johns

Faculty Publications

Ocean warming linked to anthropogenic climate change is impacting the ecology of marine species around the world. In 2010, the Gulf of Maine and Scotian Shelf regions of the Northwest Atlantic underwent an unprecedented regime shift. Forced by climate-driven changes in the Gulf Stream, warm slope waters entered the region and created a less favorable foraging environment for the endangered North Atlantic right whale population. By mid-decade, right whales had shifted their late spring/summer foraging grounds from the Gulf of Maine and the western Scotian Shelf to the Gulf of St. Lawrence. The population also began exhibiting unusually high …

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Microbial Activity Responses To Water Stress In Agricultural Soils From Simple And Complex Crop Rotations, Jorg Schnecker, D. Boone Meeden, Francisco Calderon, Michel Cavigelli, R. Michael Lehman, Lisa K. Tiemann, A. Stuart Grandy Aug 2021

Microbial Activity Responses To Water Stress In Agricultural Soils From Simple And Complex Crop Rotations, Jorg Schnecker, D. Boone Meeden, Francisco Calderon, Michel Cavigelli, R. Michael Lehman, Lisa K. Tiemann, A. Stuart Grandy

Faculty Publications

Increasing climatic pressures such as drought and flooding challenge agricultural systems and their management globally. How agricultural soils respond to soil water extremes will influence biogeochemical cycles of carbon and nitrogen in these systems. We investigated the response of soils from long-term agricultural field sites under varying crop rotational complexity to either drought or flooding stress. Focusing on these contrasting stressors separately, we investigated soil heterotrophic respiration during single and repeated stress cycles in soils from four different sites along a precipitation gradient (Colorado, MAP 421 mm; South Dakota, MAP 580 mm; Michigan, MAP 893 mm; Maryland, MAP 1192 mm); …

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Spatiotemporal Trends And Variability In The Centroid Of The Northern Hemisphere's Circumpolar Vortex, Nazla Bushra, Robert V. Rohli Aug 2021

Spatiotemporal Trends And Variability In The Centroid Of The Northern Hemisphere's Circumpolar Vortex, Nazla Bushra, Robert V. Rohli

Faculty Publications

Recent previous research has established the "sharpest gradient" approach to defining the circumpolar vortex and has identified correlations of the area and circularity of the Northern Hemisphere's circumpolar vortex (NHCPV) to important atmospheric-oceanic teleconnections. However, because geographical shifts in the NHCPV, independent of area or circularity changes, could affect surface environmental conditions, this research addresses the question of the extent to which the NHCPV centroid undergoes such shifts, both intra- and inter-annually. Results show that during the 1979-2017 period, the centroid has moved less on a daily basis in more recent years, perhaps indicative of a stabilization in circulation, with …

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Divergent Controls Of Soil Organic Carbon Between Observations And Process-Based Models, Katerina Georgiou, Avni Malhotra, William R. Wieder, Jacqueline H. Ennis, Melannie D. Hartman, Benjamin N. Sulman, Asmeret Asefaw Berhe, A. Stuart Grandy, Emily Kyker-Snowman, Kate Lajtha, Jessica A. M. Moore, Derek Pierson, Robert B. Jackson Jul 2021

Divergent Controls Of Soil Organic Carbon Between Observations And Process-Based Models, Katerina Georgiou, Avni Malhotra, William R. Wieder, Jacqueline H. Ennis, Melannie D. Hartman, Benjamin N. Sulman, Asmeret Asefaw Berhe, A. Stuart Grandy, Emily Kyker-Snowman, Kate Lajtha, Jessica A. M. Moore, Derek Pierson, Robert B. Jackson

Faculty Publications

The storage and cycling of soil organic carbon (SOC) are governed by multiple co-varying factors, including climate, plant productivity, edaphic properties, and disturbance history. Yet, it remains unclear which of these factors are the dominant predictors of observed SOC stocks, globally and within biomes, and how the role of these predictors varies between observations and process-based models. Here we use global observations and an ensemble of soil biogeochemical models to quantify the emergent importance of key state factors – namely, mean annual temperature, net primary productivity, and soil mineralogy – in explaining biome- to global-scale variation in SOC stocks. We …

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Leveraging Natural Resources Toward Resilience: Outreach, Restoration, And Monitoring For A Resilient Nh Coast, Alyson Eberhardt, David M. Burdick, Gregg E. Moore Jul 2021

Leveraging Natural Resources Toward Resilience: Outreach, Restoration, And Monitoring For A Resilient Nh Coast, Alyson Eberhardt, David M. Burdick, Gregg E. Moore

Faculty Publications

Both sound science and meaningful community engagement are critical to creating resilient coastlines given that important natural resources and high population densities coexist in these areas. Salt marshes and sand dunes provide important benefits to the people who live near them, such as mitigating flood impacts, when the condition of the ecosystem is robust enough to support such functions. To enhance the ability of these systems to perform ecosystem services, the goals of this project were to 1. Empower landowners to sustainably manage their own property to support coastal ecosystems and the benefits they provide, 2. Restore eroded sand dunes …

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An Operational Overview Of The Export Processes In The Ocean From Remote Sensing (Exports) Northeast Pacific Field Deployment, David A. Siegel, Ivona Cetinic, Jason R. Graff, Craig M. Lee, Norman Nelson, Mary Jane Perry, Inia Soto Ramos, Deborah K. Steinberg, Ken Buesseler, Roberta Hamme, Andrea J. Fassbender, David Nicholson, Melissa M. Omand, Marie Robert, Andrew Thompson, Vinicius Amaral, Michael Behrenfeld, Claudia R. Benitez-Nelson, Kelsey Bisson, Emmanuel Boss, Et. Al. Jul 2021

An Operational Overview Of The Export Processes In The Ocean From Remote Sensing (Exports) Northeast Pacific Field Deployment, David A. Siegel, Ivona Cetinic, Jason R. Graff, Craig M. Lee, Norman Nelson, Mary Jane Perry, Inia Soto Ramos, Deborah K. Steinberg, Ken Buesseler, Roberta Hamme, Andrea J. Fassbender, David Nicholson, Melissa M. Omand, Marie Robert, Andrew Thompson, Vinicius Amaral, Michael Behrenfeld, Claudia R. Benitez-Nelson, Kelsey Bisson, Emmanuel Boss, Et. Al.

Faculty Publications

The goal of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) field campaign is to develop a predictive understanding of the export, fate, and carbon cycle impacts of global ocean net primary production. To accomplish this goal, observations of export flux pathways, plankton community composition, food web processes, and optical, physical, and biogeochemical (BGC) properties are needed over a range of ecosystem states. Here we introduce the first EXPORTS field deployment to Ocean Station Papa in the Northeast Pacific Ocean during summer of 2018, providing context for other papers in this special collection. The experiment was conducted with …

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Molecular Markers Of Biogenic And Oil-Derived Hydrocarbons In Deep-Sea Sediments Following The Deepwater Horizon Spill, Isabel C. Romero, Jeffrey P. Chanton, Gregg Brooks, Samantha Bosman, Rebekka A. Larson, Austin Harris, Patrick Schwing, Arne Diercks Jul 2021

Molecular Markers Of Biogenic And Oil-Derived Hydrocarbons In Deep-Sea Sediments Following The Deepwater Horizon Spill, Isabel C. Romero, Jeffrey P. Chanton, Gregg Brooks, Samantha Bosman, Rebekka A. Larson, Austin Harris, Patrick Schwing, Arne Diercks

Faculty Publications

Following the Deepwater Horizon oil spill (DWHOS), the formation of an unexpected and extended sedimentation event of oil-associated marine snow (MOSSFA: Marine Oil Snow Sedimentation and Flocculent Accumulation) demonstrated the importance of biology on the fate of contaminants in the oceans. We used a wide range of compound-specific data (aliphatics, hopanes, steranes, triaromatic steroids, polycyclic aromatics) to chemically characterize the MOSSFA event containing abundant and multiple hydrocarbon sources (e.g., oil residues and phytoplankton). Sediment samples were collected in 2010–2011 (ERMA-NRDA programs: Environmental Response Management Application – Natural Resource Damage Assessment) and 2018 (REDIRECT project: Resuspension, Redistribution and Deposition of Deepwater …

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Concentrations, Ratios, And Sinking Fluxes Of Major Bioelements At Ocean Station Papa, Montserrat Roca-Martí Jun 2021

Concentrations, Ratios, And Sinking Fluxes Of Major Bioelements At Ocean Station Papa, Montserrat Roca-Martí

Faculty Publications

Fluxes of major bioelements associated with sinking particles were quantified in late summer 2018 as part of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) field campaign near Ocean Station Papa in the subarctic northeast Pacific. The thorium-234 method was used in conjunction with size-fractionated (1–5, 5–51, and >51 μm) concentrations of particulate nitrogen (PN), total particulate phosphorus (TPP), biogenic silica (bSi), and particulate inorganic carbon (PIC) collected using large volume filtration via in situ pumps. We build upon recent work quantifying POC fluxes during EXPORTS. Similar remineralization length scales were observed for both POC and PN across …

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Review Of The Analysis Of 234Th In Small Volume (2–4 L) Seawater Samples: Improvements And Recommendations, Samantha J. Clevenger, Claudia Benitez-Nelson, Jessica Drysdale, Steven Pike, Viena Puigcorbé, Ken O. Buesseler Jun 2021

Review Of The Analysis Of 234Th In Small Volume (2–4 L) Seawater Samples: Improvements And Recommendations, Samantha J. Clevenger, Claudia Benitez-Nelson, Jessica Drysdale, Steven Pike, Viena Puigcorbé, Ken O. Buesseler

Faculty Publications

Schools may be one important context where adolescents learn and shape the behaviors necessary for promoting global inclusivity in adulthood. Given the importance of bystanders in halting bullying and peer aggression, the focus of this study is on both moral judgments regarding one type of bullying, social exclusion, and factors that are associated with bystander intervention. The study includes 896 adolescents, who were 6th (N = 450, Mage = 11.73), and 9th (N = 446, Mage = 14.82) graders, approximately evenly divided by gender. Participants were primarily European–American (63.3%). Results revealed that girls and participants who …

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Biogenic Sinking Particle Fluxes And Sediment Trap Collection Efficiency At Ocean Station Papa, Margaret Estapa, Ken Buesseler, Collen A. Durkin, Melissa Omand, Claudia Benitez-Nelson, Montserrat Rocca-Martí, Elly Breves, R. P. Kelly, Steve Pike Jun 2021

Biogenic Sinking Particle Fluxes And Sediment Trap Collection Efficiency At Ocean Station Papa, Margaret Estapa, Ken Buesseler, Collen A. Durkin, Melissa Omand, Claudia Benitez-Nelson, Montserrat Rocca-Martí, Elly Breves, R. P. Kelly, Steve Pike

Faculty Publications

Comprehensive field observations characterizing the biological carbon pump (BCP) provide the foundation needed to constrain mechanistic models of downward particulate organic carbon (POC) flux in the ocean. Sediment traps were deployed three times during the EXport Processes in the Ocean from RemoTe Sensing campaign at Ocean Station Papa in August–September 2018. We propose a new method to correct sediment trap sample contamination by zooplankton “swimmers.” We consider the advantages of polyacrylamide gel collectors to constrain swimmer influence and estimate the magnitude of possible trap biases. Measured sediment trap fluxes of thorium-234 are compared to water column measurements to assess trap …

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Effects Of Timber Harvest On Epigeous Fungal Fruiting Patterns And Community Structure In A Northern Hardwood Ecosystem, Benjamin W. Borgmann-Winter, Ryan B. Stephens, Anthony W. D'Amato, Serita D. Frey, Rebecca J. Rowe May 2021

Effects Of Timber Harvest On Epigeous Fungal Fruiting Patterns And Community Structure In A Northern Hardwood Ecosystem, Benjamin W. Borgmann-Winter, Ryan B. Stephens, Anthony W. D'Amato, Serita D. Frey, Rebecca J. Rowe

Faculty Publications

Epigeous fungal fruiting has important impacts on fungal reproduction and ecosystem function. Forest disturbances, such as timber harvest, impact moisture, host availability, and substrate availability, which in turn may drive changes in fungal fruiting patterns and community structure. We surveyed mushrooms in 0.4 ha patch cuts (18 months post-harvest) and adjacent intact hardwood forest in northern New Hampshire, USA, to document the effects of timber harvest on summer fruiting richness, biomass, diversity, and community structure of ectomycorrhizal, parasitic, and saprobic mushroom taxa. Fungal fruiting richness, diversity, and community heterogeneity were greater in intact forests than patch cuts. Among functional groups, …

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Ocean-Atmosphere Interactions During Hurricanes Marco And Laura (2020), Emily N. Eley, Bulusu Subrahmanyam, Corinne B. Trott May 2021

Ocean-Atmosphere Interactions During Hurricanes Marco And Laura (2020), Emily N. Eley, Bulusu Subrahmanyam, Corinne B. Trott

Faculty Publications

During August of the 2020 Atlantic Hurricane Season, the Gulf of Mexico (GoM) was affected by two subsequent storms, Hurricanes Marco and Laura. Hurricane Marco entered the GoM first (22 August) and was briefly promoted to a Category 1 storm. Hurricane Laura followed Marco closely (25 August) and attained Category 4 status after a period of rapid intensification. Typically, hurricanes do not form this close together; this study aims to explain the existence of both hurricanes through the analysis of air-sea fluxes, local thermodynamics, and upper-level circulation. The GoM and its quality of warm, high ocean heat content waters proved …

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De Novo Transcriptome Assembly Of The Green Alga Ankistrodesmus Falcatus, Rachel A. Schomaker, Jeffry L. Dudycha May 2021

De Novo Transcriptome Assembly Of The Green Alga Ankistrodesmus Falcatus, Rachel A. Schomaker, Jeffry L. Dudycha

Faculty Publications

Ankistrodesmus falcatus is a globally distributed freshwater chlorophyte that is a candidate for biofuel production, is used to study the effects of toxins on aquatic communities, and is used as food in zooplankton research. Each of these research fields is transitioning to genomic tools. We created a reference transcriptome for of A. falcatus using NextGen sequencing and de novo assembly methods including Trinity, Velvet-Oases, and EvidentialGene. The assembled transcriptome has a total of 17,997 contigs, an N50 value of 2,462, and a GC content of 64.8%. BUSCO analysis recovered 83.3% of total chlorophyte BUSCOs and 82.5% of the eukaryotic …

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Fungal Community Response To Long-Term Soil Warming With Potential Implications For Soil Carbon Dynamics, Gregory J. Pec, Linda T. A. Van Diepen, Melissa A. Knorr, A. Stuart Grandy, Jerry M. Melillo, Kristen M. Deangelis, Jeffrey L. Blanchard, Serita D. Frey May 2021

Fungal Community Response To Long-Term Soil Warming With Potential Implications For Soil Carbon Dynamics, Gregory J. Pec, Linda T. A. Van Diepen, Melissa A. Knorr, A. Stuart Grandy, Jerry M. Melillo, Kristen M. Deangelis, Jeffrey L. Blanchard, Serita D. Frey

Faculty Publications

The direction and magnitude of climate warming effects on ecosystem processes such as carbon cycling remain uncertain. Soil fungi are central to these processes due to their roles as decomposers of soil organic matter, as mycorrhizal symbionts, and as determinants of plant diversity. Yet despite their importance to ecosystem functioning, we lack a clear understanding of the long-term response of soil fungal communities to warming. Toward this goal, we characterized soil fungal communities in two replicated soil warming experiments at the Harvard Forest (Petersham, Massachusetts, USA) which had experienced 5°C above ambient soil temperatures for 5 and 20 yr at …

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