Biogeochemistry Commons^™

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, …

Carbonate Paleothermometry In Fayetteville Green Lake, New York, Micah Wiesner

Theses - ALL

Lacustrine carbonates are important paleoclimate archives, but unknowns in the seasonal timing and depth of precipitation obscure the interpretation of temperatures associated with them. The clumped isotope paleothermometer records the formation temperature T(D47) of carbonates. This study examines a set of lacustrine carbonates formed in the water column, in addition to carbonate from a sediment core, to better understand the depth and seasonality of carbonate formation in a lacustrine setting. We test that, regardless of season and formation temperature, lacustrine carbonates form in isotopic equilibrium with respect to D47 and d18O fractionation. Further, we account for the effect of our …

Carbonate Paleothermometry In Fayetteville Green Lake, New York, Micah Wiesner

Theses - ALL

Lacustrine carbonates are important paleoclimate archives, but unknowns in the seasonal timing and depth of precipitation obscure the interpretation of temperatures associated with them. The clumped isotope paleothermometer records the formation temperature T(D47) of carbonates. This study examines a set of lacustrine carbonates formed in the water column, in addition to carbonate from a sediment core, to better understand the depth and seasonality of carbonate formation in a lacustrine setting. We test that, regardless of season and formation temperature, lacustrine carbonates form in isotopic equilibrium with respect to D47 and d18O fractionation. Further, we account for the effect of our …

Incorporating Life Into Living Shorelines: Can Gulf Ribbed Mussels Reduce Shoreline Erosion And Enhance Restoration Practices?, Jordan Logarbo

LSU Master's Theses

The gulf ribbed mussel (Geukensia granosissima) exists throughout the Gulf of Mexico and influences biotic and abiotic environmental attributes as an ecosystem engineer. Ribbed mussels are an important component of marsh ecosystems providing services including filtering particulate matter, depositing and transforming nutrients in the system, increasing soil strength via byssal threads and providing structure via their shells.

The spatial distribution of mussels along the marsh edge of Sister Lake, LA was investigated via a broad survey of 150 sites, in relation to elevation, exposure and vegetation percent cover. This survey was followed by a second survey at a …

Linking Human Activities To Water Quality In Coastal New England: Past And Present, Amelia Hurst

University Scholar Projects

This project examines the timing and effect of direct and indirect anthropogenic and natural influences on the marine environment in embayments in southern New England over the past decades to century timescale. We investigated the effects of human land use from colonial through post-industrial times, determined baseline conditions and natural climatic variability, and analyzed the response of marine ecosystems to specific local management actions aimed to improve water quality. A coastal sediment core was taken in Mumford Cove, CT and was analyzed downcore for eutrophication markers (C: N, %C, %N, d¹⁵N, d¹³C) and metals (Hg, Pb, …

Effects Of Environmental Change On Ancestral Pueblo Fishing In The Middle Rio Grande, Jonathan William Dombrosky

Anthropology ETDs

It has long been assumed that fishes were unimportant in the diet of past Pueblo people in the U.S. Southwest. Yet, small numbers of fish remains are consistently recovered from Late pre-Hispanic/Early Historic archaeological sites in the Middle Rio Grande of New Mexico. The end of drought conditions may have impacted food choice and fishing decisions during this time. I use behavioral ecology to understand how fishing could have been an optimal food-getting strategy for Ancestral Pueblo farmers. Stable isotope analysis offers a way to account for environmental change. I provide a refined ¹³C Suess correction model to support …

Management Intensive Grazing On New England Dairy Farms Enhances Soil Nitrogen Stocks And Elevates Soil Nitrous Oxide Emissions Without Increasing Soil Carbon, Alexandra R. Contosta, Kyle A. Arndt, Eleanor E. Campbell, A. Stuart Grandy, Apryl L. Perry, Ruth K. Varner

Faculty Publications

Management intensive grazing (MIG), also known as rotational grazing or multi-paddock grazing, is purported to sequester carbon (C) in soils compared to other agricultural management systems. Prior research examining the potential for MIG to enhance soil C has been inconclusive, and past investigations have not addressed whether higher nitrous oxide (N2O) emissions may accompany increases in soil C stocks. Here we examined linkages among MIG, soil C accumulation, and N2O emissions in cool-season, organic pastures of the northeastern United States. We found that pastures under MIG increased soil C concentrations by 11% from 0–15 cm depth but that soil C …

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 …

Active Layer Thickness As A Function Of Soil Water Content, Leah K. Clayton, Kevin Schaefer, Michael Battaglia, Laura Bourgeau-Chavez, Jingyi Chen, Richard H. Chen, Albert Chen, Kazem Bakian-Dogaheh, Sarah L. Grelik, Elchin Jafarov, Lin Liu, Roger John Michaelides, Mahta Moghaddam, Andrew D. Parsekian, Adrian V. Rocha, Sean R. Schaefer, Taylor Sullivan, Alireza Tabatabaeenejad, Kang Wang, Cathy J. Wilson, Howard A. Zebker, Tingjun Zhang, Yuhuan Zhao

Michigan Tech Publications, Part 1

Active layer thickness (ALT) is a critical metric for monitoring permafrost. How soil moisture influences ALT depends on two competing hypotheses: (a) increased soil moisture increases the latent heat of fusion for thaw, resulting in shallower active layers, and (b) increased soil moisture increases soil thermal conductivity, resulting in deeper active layers. To investigate their relative influence on thaw depth, we analyzed the Field Measurements of Soil Moisture and Active Layer Thickness (SMALT) in Alaska and Canada dataset, consisting of thousands of measurements of thaw depth and soil moisture collected at dozens of sites across Alaska and Canada as part …

A Holistic Framework Integrating Plant-Microbe-Mineral Regulation Of Soil Bioavailable Nitrogen, Amanda B. Daly, Andrea Jilling, Timothy M. Bowles, Robert W. Buchowski, Serita D. Frey, Cynthia M. Kallenbach, Marco Keiluweit, Maria Mooshammer, Joshua P. Schimel, A. Stuart Grandy

Faculty Publications

Soil organic nitrogen (N) is a critical resource for plants and microbes, but the processes that govern its cycle are not well-described. To promote a holistic understanding of soil N dynamics, we need an integrated model that links soil organic matter (SOM) cycling to bioavailable N in both unmanaged and managed landscapes, including agroecosystems. We present a framework that unifies recent conceptual advances in our understanding of three critical steps in bioavailable N cycling: organic N (ON) depolymerization and solubilization; bioavailable N sorption and desorption on mineral surfaces; and microbial ON turnover including assimilation, mineralization, and the recycling of microbial …

Sodah: The Soils Data Harmonization Database, An Open-Source Synthesis Of Soil Data From Research Networks, Version 1.0, William R. Wieder, Derek Pierson, Stevan Earl, Kate Lajtha, Sara G. Baer, Ford Ballantyne, Asmeret Asefaw Berhe, Sharon A. Billings, Laurel M. Brigham, Stephany S. Chacon, Jennifer Fraterrigo, Serita D. Frey, Katerina Georgiou, Marie-Anne De Graaff, A. Stuart Grandy, Melannie D. Hartman, Sarah E. Hobbie, Chris Johnson, Jason Kaye, Emily Kyker-Snowman, Marcy E. Litvak, Michelle C. Mack, Avni Malhotra, Jessica A. M. Moore, Knute Nadelhoffer, Craig Rasmussen, Whendee L. Silver, Benjamin N. Sulman, Xanthe Walker, Samantha Weintraub

Faculty Publications

Data collected from research networks present opportunities to test theories and develop models about factors responsible for the long-term persistence and vulnerability of soil organic matter (SOM). Synthesizing datasets collected by different research networks presents opportunities to expand the ecological gradients and scientific breadth of information available for inquiry. Synthesizing these data is challenging, especially considering the legacy of soil data that have already been collected and an expansion of new network science initiatives. To facilitate this effort, here we present the SOils DAta Harmonization database (SoDaH; https://lter.github.io/som-website, last access: 22 December 2020), a flexible database designed to harmonize diverse …

Organic Matter Spatial And Temporal Patterns In Coastal Sands Of Long Bay, South Carolina, Kayla B. Christofferson

Honors Theses

Sandy coastlines serve crucial functions to coastal economies and coastal ecology alike. In the past, organic-poor sands were considered of lower importance than organic-rich muds. Recent studies showed that sands’ low organic matter concentrations are due to high biogeochemical cycling rates, driven by rapid physical exchange, but remain infrequently studied. I present time-series of sand mass-loss-on-ignition (LOI, an organic matter proxy) profiles from February 2017 onwards at multiple sites along Long Bay, South Carolina. LOI profiles exhibit subsurface maximum values, unlike the typical decrease with depth in muddy sediments. I hypothesize that organic matter distribution with depth is affected by …

Isolated Point Discharges Into Coastal Swashes As Nutrient Sources To Coastal Waters, Mary E. Olsen

Honors Theses

Coastal water quality in the Grand Strand of South Carolina is directly influenced by human activities. Nutrient-rich runoff, stemming from numerous anthropogenic sources, finds its way into coastal waters through freshwater inputs often through tidal creeks, termed swashes. In order to better describe the amount of nutrient inputs into Singleton Swash and White Point Swash, we examine anthropogenic runoff from isolated identifiable point discharges and their nutrient concentrations. We report concentrations of dissolved inorganic nitrogen (DIN, as the sum of nitrate, nitrite and ammonium) and phosphate in discharge and creek water. We hypothesize that nutrient concentrations of isolated, minor point …

Microplankton Dynamics In The River-Dominated Mississippi Bight, Adam D. Boyette

Dissertations

The Mississippi Bight (MSB) is a river-dominated continental margin influenced by multiple large river systems, including the Mississippi River, Alabama and Tombigbee rivers via Mobile Bay, and numerous smaller rivers, creeks, and bayous. This is part of a biologically-rich ecosystem that supports the second largest fishery industry by volume in the United States. Despite our understanding of the linkages between primary production with higher trophic levels, there remains limited studies quantifying these trophic interactions in this system. Microplankton (µm) community dynamics and trophic connectivity between primary producers and heterotrophic protists represent a critical nexus influencing overall biological productivity in this …

Geological Problems With Microbiological Solutions: Deciphering The Authigenesis Of Calcite, Dolomite, And Native Sulfur In Salty Environments, Amanda L. Labrado

Open Access Theses & Dissertations

Microbial activity is known to impact the formation and alteration of many different rock types. For carbonate caprock (CCR), a lithology found on salt diapirs, it is generally accepted that microbial activity drives the precipitation of carbonate minerals, forming limestone and/or dolomite and native (elemental) sulfur. It appears that there are two types of CCR: 1) limestone associated with native sulfur (S0) and 2) limestone associated with dolomite. The mechanics of CCR formation are poorly understood. For example, it is unclear why native sulfur and dolomite are rarely found in the same CCR assemblage, and why either are formed at …

Effects Of The Triassic-Jurassic Central Atlantic Magmatic Event Recorded In Continental Strata In Western Pangea: The Δ13c Record Of Warner Valley & Zion National Park, Dennis Mmasa

Graduate Theses and Dissertations

The Triassic is a period of abrupt climate change bracketed by mass extinctions including one driven by the eruption of the Central Atlantic Magmatic Province (CAMP) in the Late Triassic. The Moenave Formation (MF) of Utah and Arizona is ideal to investigate effects of the CAMP on continental strata distal to the eruptive center. This study focuses on the C-isotopic composition of bulk carbonate C from two localities, Blacks Canyon, Zion National Park, UT and Olsen Canyon within Warner Valley, UT. The data collected was used to document a chemostratigraphic record to compare to globally established records and bulk organic …

Microbially-Mediated Carbonate Dissolution And Precipitation; Towards A Protocol For Ex-Situ, Cave-Analogue Cultivation Experiments, Vanessa E. Johnston, Andrea Martín-Pérez, Sara Skok, Janez Mulec

International Journal of Speleology

Subterranean calcite dissolution and precipitation are often considered as strictly geochemical processes. The active involvement of microbes in these processes is commonly underestimated in the literature due to general oligotrophic conditions in caves, except in particular cave conditions, such as sulfidic caves and moonmilk deposits, where the presence of microbes likely plays a key role in mineral deposition. Here, we study the possible involvement of microbes from Postojna Cave, Slovenia, in carbonate dissolution (litholysis) and precipitation (lithogenesis). Microbes were sampled from small pools below hydrologically diverse drip sites and incubated on polished limestone tablets at 10 and 20°C for 2 …

Is A Common Goal A False Hope In Convergence Research?: Opportunities And Challenges Of International Convergence Research To Address Arctic Change, Jessica G. Ernakovich, N. Eklund, Ruth K. Varner, N. Kirchner, J. Jeuring, Katharine Duderstadt, A. Granebeck, E. Golubeva, Asiaq Participants

Faculty Publications

The Arctic faces multiple pressures including climate change, shifting demographics, human health risks, social justice imbalances, governance issues, and expanding resource extraction. A convergence of academic disciplines—such as natural and social sciences, engineering and technology, health and medicine—and international perspectives is required to meaningfully contribute to solving the challenges of Arctic peoples and ecosystems. However, successfully carrying out convergent, international research and education remains a challenge. Here, lessons from the planning phase of a convergence research project concerned with the health of Arctic waters developed by the Arctic Science IntegrAtion Quest (ASIAQ) are discussed. We discuss our perspective on the …

Alexandrium In The Arctic: Are Harmful Algae Spreading As The Arctic Warms?, Sveinn Einarsson, Kate Lowry, Robert Pickart, Karin Ashjian, P. Dreux Chappell

College of Sciences Posters

Alexandrium tamerense is a well-studied dinoflagellate known for its ability to produce the neurotoxin that causes paralytic shellfish poisoning. Until 1970 Alexandrium tamerense was only found in Europe, North America, and Japan but has been increasingly found all over the globe. Alexandrium is characteristically found in temperate and subtropical regions and as the Arctic warms, there is considerable concern that it may be expanding into the Arctic. We found Alexandrium tamerense during a research expedition to the Alaskan Beaufort Sea shelf to study upwelling. Upwelling events are known to support seasonal blooms of phytoplankton, which are important primary producers at …

Seasonal Variability In Diazotroph Abundance And Gene Expression At A Coastal N2 Fixation Hotspot (Outer Banks, Nc), Katherine Crider, Corday Selden, Kimberly Powell, P. Dreux Chappell

College of Sciences Posters

Marine microbial dinitrogen (N₂) fixation, the conversion of gaseous N₂ to bioavailable species, is the primary source of new oceanic nitrogen (N). N is present in nucleic acids, amino acids, and proteins, and is essential to all life. Long considered to be a primarily oligotrophic ocean process, significant N₂ fixation rates have recently been observed in coastal environments, including along the Cape Hatteras front. To see if elevated N₂ fixation was a persistent feature in this region, N₂ fixation rates and N₂ fixer (diazotroph) abundance and gene expression were investigated through roughly monthly …