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Full-Text Articles in Life Sciences

Ecological Monitoring Program At Vims Esl: Annual Report 2023, Paige G. Ross, Richard A. Snyder Apr 2024

Ecological Monitoring Program At Vims Esl: Annual Report 2023, Paige G. Ross, Richard A. Snyder

Reports

An Ecological Monitoring Program (EMP) has been established at the Virginia Institute of Marine Science Eastern Shore Laboratory (VIMS ESL) for the coastal environment near the Wachapreague lab. The goals of the initiative are to 1) provide status and trends information to scientists who study and regulators who manage Virginia’s marine resources, 2) provide a scientific context for short-term research and grant proposals 3) provide pedagogical enrichment for educators to use in their classes, and 4) build capacity in staff expertise and training of interns and students at VIMS ESL.

The program formalizes and standardizes data collection for a long-term …


Aquaculture Governance: Five Engagement Arenas For Sustainability Transformation, Darien D. Mizuta, Stefan Partelow Dec 2023

Aquaculture Governance: Five Engagement Arenas For Sustainability Transformation, Darien D. Mizuta, Stefan Partelow

VIMS Articles

A greater focus on governance is needed to facilitate effective and substantive progress toward sustainability transformations in the aquaculture sector. Concerted governance efforts can help move the sector beyond fragmented technical questions associated with intensification and expansion, social and environmental impacts, and toward system-based approaches that address interconnected sustainability issues. Through a review and expert-elicitation process, we identify five engagement arenas to advance a governance agenda for aquaculture sustainability transformation: (1) setting sustainability transformation goals, (2) cross-sectoral linkages, (3) land–water–sea connectivity, (4) knowledge and innovation, and (5) value chains. We then outline the roles different actors and modes of …


Fecal Pellet Production By North Atlantic Zooplankton, Michael Gibson May 2023

Fecal Pellet Production By North Atlantic Zooplankton, Michael Gibson

Undergraduate Honors Theses

Fecal pellet carbon (FPC) production by zooplankton is a significant component of the ocean’s biological carbon pump: the suite of biological processes that mediate export of carbon to the deep ocean, ultimately leading to the sequestration of atmospheric carbon dioxide in the ocean. In this study, mesozooplankton (zooplankton 0.2 mm to ~2 cm) were collected from the epipelagic zone in the temperate North Atlantic Ocean during day and night in May 2021. Zooplankton were live separated into five size fractions and incubated on board ship in natural surface seawater to measure fecal pellet production rate of the mixed mesozooplankton community. …


From Field To Shore: Policy Improvements To Better Protect Ecosystem And Human Health From Poultry Wastes In Virginia, Rachael A. King Jan 2023

From Field To Shore: Policy Improvements To Better Protect Ecosystem And Human Health From Poultry Wastes In Virginia, Rachael A. King

Dissertations, Theses, and Masters Projects

Commercial poultry production is a large industry with economic importance in Virginia. However, mismanagement of manures and wastes generated from the poultry industry can be a serious threat to ecosystem and human health. Primarily, there is a concern about nutrient pollution related to runoff and infiltration of poultry wastes. High nutrient loading can cause groundwater contamination, eutrophication, and harmful algal blooms (HABs). Additional concerns include metals, antibiotics, and pesticides that can be found in poultry wastes. To determine existing threats to ecosystem and human health from the poultry industry, Virginia policies regulating the industry are reviewed and their strengths and …


Tracing Atlantic Sea Scallops Using Radio Frequency Identification (Rfid) Technology, Will Shoup Jan 2023

Tracing Atlantic Sea Scallops Using Radio Frequency Identification (Rfid) Technology, Will Shoup

Dissertations, Theses, and Masters Projects

Traceable seafood can be linked back to its origin and method of catch. Improving the traceability of marine organisms involves establishing a transparent Chain of Custody (CoC) by collecting data at checkpoints throughout the supply chain, from ship to shore to store. This report explores the feasibility of integrating Radio Frequency Identification (RFID) technology into the United States Atlantic sea scallop (Placopecten magellanicus) fishery in order to improve traceability. This report serves as a forward-looking evaluation of RFID technology that is intended to inform interested stakeholders of its functionality and capabilities. It is not intended to serve as a management …


Impacts And Uncertainties Of Climate Change On The Chesapeake Bay, Kyle E. Hinson Jan 2023

Impacts And Uncertainties Of Climate Change On The Chesapeake Bay, Kyle E. Hinson

Dissertations, Theses, and Masters Projects

Climate change impacts in the Chesapeake Bay will limit the efficacy of nutrient reduction efforts and decrease dissolved oxygen, but uncertainties associated with the magnitude of these effects remain. An understanding of underlying mechanisms that have driven recent warming trends will narrow uncertainties for future pathways of temperature change. Additionally, future simulations of climate impacts in the estuary are dependent on multiple different sources of uncertainty, many of which have not yet been fully evaluated. This dissertation used a three- dimensional coupled hydrodynamic-biogeochemical model to investigate recent warming trends as well as underlying uncertainties likely to influence regional projections of …


Ecological Monitoring Program At Vims Esl: Annual Report 2022, Paige G. Ross, Richard A. Snyder Jan 2023

Ecological Monitoring Program At Vims Esl: Annual Report 2022, Paige G. Ross, Richard A. Snyder

Reports

An Ecological Monitoring Program (EMP) has been established at the Virginia Institute of Marine Science Eastern Shore Laboratory (VIMS ESL) for the coastal environment near the Wachapreague lab. The goals of the initiative are to 1) provide status and trends information to scientists who study and regulators who manage Virginia’s marine resources, 2) provide a scientific context for short-term research and grant proposals 3) provide pedagogical enrichment for educators to use in their classes, and 4) build capacity in staff expertise and training of interns and students at VIMS ESL.

The program formalizes and standardizes data collection for a long-term …


Center For Coastal Resources Management Annual Report 2022, Center For Coastal Resources Management Jan 2023

Center For Coastal Resources Management Annual Report 2022, Center For Coastal Resources Management

Reports

No abstract provided.


Influence Of Oyster Genetic Background On Levels Of Human-Pathogenic Vibrio Spp., Corinne Audemard, Kimberly S. Reece, Robert J. Latour, Lydia M. Bienlien, Ryan B. Carnegie Aug 2022

Influence Of Oyster Genetic Background On Levels Of Human-Pathogenic Vibrio Spp., Corinne Audemard, Kimberly S. Reece, Robert J. Latour, Lydia M. Bienlien, Ryan B. Carnegie

VIMS Articles

Human-pathogenic Vibrio bacteria are common inhabitants of oyster tissues, but our understanding of factors driving the wide range of concentrations found in individual oysters is extremely limited. We examined the influence of oyster sex and parasitism in light of their profound effects on oyster tissues against a backdrop of eastern oysters, Crassostrea virginica, from two diploid and two triploid aquacultured lines. This allowed us to examine not only the effect of oyster ploidy but also of oyster genetics, a factor never investigated with regard to human-pathogenic Vibrio species. We measured levels of total Vibrio vulnificus (vvhA), and of …


Chesapeake Bay National Estuarine Research Reserve In Virginia Management Plan: 2022-2027, W. G. Reay, J. Baber, H. Brooks, A. Demeo, C. T. Friedrichs, C. Gonzales, J. Kuriawa, T. Hooper, S. Lerberg, E. J. Miles, B. Neikirk, S. Nuss, L. Ott, D. Parrish, T. Rudo, E C. Shields, S. Snyder, S. Wood Aug 2022

Chesapeake Bay National Estuarine Research Reserve In Virginia Management Plan: 2022-2027, W. G. Reay, J. Baber, H. Brooks, A. Demeo, C. T. Friedrichs, C. Gonzales, J. Kuriawa, T. Hooper, S. Lerberg, E. J. Miles, B. Neikirk, S. Nuss, L. Ott, D. Parrish, T. Rudo, E C. Shields, S. Snyder, S. Wood

Reports

Established through the Coastal Zone Management Act, the National Estuarine Research Reserve System (NERRS) represents a partnership program between the National Oceanic and Atmospheric Administration (NOAA) and the coastal states to promote informed management of the Nation’s estuaries and habitats. Designated in 1991, and administered by the Virginia Institute of Marine Science (VIMS) of William & Mary, the Chesapeake Bay National Estuarine Research Reserve in Virginia (CBNERR-VA or Reserve) is one of 30 protected areas, which encompass over 1.3 million acres and make up the NERRS.

As the nation's largest estuary, the Chesapeake Bay contains a diverse collection of habitats …


Climate Change And Conservation Of Milkweed: Evidence Of Extensive Admixture Between Common Milkweed And Poke Milkweed, Elizabeth Davies May 2022

Climate Change And Conservation Of Milkweed: Evidence Of Extensive Admixture Between Common Milkweed And Poke Milkweed, Elizabeth Davies

Undergraduate Honors Theses

Global climate change can drive many changes in species interactions. One primary way it affects species is by changing climates, causing species to expand their ranges and allowing them to interact with species from whom they were previously isolated. In plants, new species interactions can result in hybridization – the creation of hybrid offspring between two separate species. This hybridization can increase gene flow between the species and lead to introgression, the transfer of genetic material from one species to another through hybrid backcrossing with the parent species. My thesis investigates hybridization in the model system Asclepias (milkweed) by analyzing …


Using Deep Learning With Satellite Imagery To Estimate Deforestation Rates, Maeve Naughton-Rockwell May 2022

Using Deep Learning With Satellite Imagery To Estimate Deforestation Rates, Maeve Naughton-Rockwell

Undergraduate Honors Theses

Previous studies have used Convolutional Neural Networks for regional detection of deforestation breaks. However, there is limited research into the capability of deep neural networks to identify sudden shifts in global forest cover from satellite imagery. Additionally, many deforestation detection models are trained on region specific data and need manual input thresholds. In this work, we develop a deep learning model to predict the percent of deforestation in a region between two points in time, trained on globally sourced data. Using the before and after satellite images of a deforestation event as inputs, we implemented a two input Convolutional Neural …


Using A Machine Learning Model To Predict Plant Inflorescences Based Upon Its Soil Microbiome, Luke Denoncourt May 2022

Using A Machine Learning Model To Predict Plant Inflorescences Based Upon Its Soil Microbiome, Luke Denoncourt

Undergraduate Honors Theses

The UN estimates that the global population could reach 9.7 billion by 2050 (United Nations). As a result, the amount of food required to feed humanity is thought to double by 2050 (Ray et al., 2012). Humanity must find a way to increase crop production without increasing fertilizer usage and eutrophication, which can be done using the soil microbiome. Using potted plants with soils inoculated with Pseudomonas alcaligenes, Pseudomonas denitrificans, Bacillus polymyxa, and Mycobacterium phlei, both the shoot and root growth of pea and cotton plants was significantly increased (Egamberdieva & Höflich, 2004). In this study, utilizing a random forest …


Modeling And Analyses Of Mechanisms Underlying Network Synaptic Dynamics In Two Neural Circuits, Linda Ma Apr 2022

Modeling And Analyses Of Mechanisms Underlying Network Synaptic Dynamics In Two Neural Circuits, Linda Ma

Undergraduate Honors Theses

In systems neuroscience, circuit models of cortical structures can be used to deconstruct mechanisms responsible for spike patterns that generate a variety of behaviors observed in the brain. In particular, mathematical simulations of these circuits can replicate complex dynamical behaviors that mirror not only macroscopically patterns observed in the brain, but also a significant amount of experimentally characterized minutiae. These models are capable of analyzing neural mechanisms by explicitly deconstructing connectivities between populations of neurons in ways that tend to be empirically inaccessible. This work presents two such models; one in the rat somatosensory barrel cortex, responsible for processing sensory …


Analysis Of Edna To Assess Effects Of Water Quality On Freshwater Fungal Diversity In A Virginia Coastal Watershed, Lauren French Apr 2022

Analysis Of Edna To Assess Effects Of Water Quality On Freshwater Fungal Diversity In A Virginia Coastal Watershed, Lauren French

Undergraduate Honors Theses

Freshwater fungi comprise a phylogenetically and functionally diverse group which contributes to wide-ranging ecosystem processes in aquatic systems. Saprotrophic fungi convert detritus into nutrient-rich food sources for fish and invertebrates, whereas pathogenic and parasitic fungi can cause disease and population declines of other aquatic organisms. With their diverse and important roles, changes in freshwater fungal community structure may have far-reaching impacts on ecosystems. To understand how natural and anthropogenic stressors to freshwater systems impact fungal-mediated ecosystem processes, a greater understanding of the taxonomic and functional composition of freshwater fungal communities is needed. We assessed relationships among freshwater habitat types, water …


Honey As A Biomonitor For Air Pollutant Deposition In The Eastern United States Using Ion Chromatography And Scanning Electron Microscopy, Cole Cochran Apr 2022

Honey As A Biomonitor For Air Pollutant Deposition In The Eastern United States Using Ion Chromatography And Scanning Electron Microscopy, Cole Cochran

Undergraduate Honors Theses

Anthropogenic activities generate metal, acid, and particulate air pollutants which negatively impact human and ecological health. In the United States, power plant, industrial, and vehicle emissions are leading causes of air pollution, however, the measurement of air pollution at high-resolution spatial regimes remains a challenge. Honey has emerged as a powerful biomonitoring tool to effectively quantify contaminants without the need for a large array of monitoring instruments. I hypothesized that honey could be used to effectively measure and map modern air pollutant spatiotemporal relationships over the Eastern U.S. Using ion chromatography with sulfate as an indicator for air pollution and …


A General Pattern Of Trade-Offs Between Ecosystem Resistance And Resilience To Tropical Cyclones, Christopher J. Patrick, John S. Kominoski, (...), Enie Hensel, Marc J. S. Hense, Bradley A. Strickland, (..), A. K. Hardison, Sean Kinard, Et Al Mar 2022

A General Pattern Of Trade-Offs Between Ecosystem Resistance And Resilience To Tropical Cyclones, Christopher J. Patrick, John S. Kominoski, (...), Enie Hensel, Marc J. S. Hense, Bradley A. Strickland, (..), A. K. Hardison, Sean Kinard, Et Al

VIMS Articles

Tropical cyclones drive coastal ecosystem dynamics, and their frequency, intensity, and spatial distribution are pre-dicted to shift with climate change. Patterns of resistance and resilience were synthesized for 4138 ecosystem time series from n = 26 storms occurring between 1985 and 2018 in the Northern Hemisphere to predict how coastal ecosystems will respond to future disturbance regimes. Data were grouped by ecosystems (fresh water, salt water, terrestrial, and wetland) and response categories (biogeochemistry, hydrography, mobile biota, sedentary fauna, and vascular plants). We observed a repeated pattern of trade-offs between resistance and resilience across analyses. These patterns are likely the outcomes …


Ecological Monitoring Program At Vims Esl: Annual Report 2021, Paige G. Ross, Richard A. Snyder Mar 2022

Ecological Monitoring Program At Vims Esl: Annual Report 2021, Paige G. Ross, Richard A. Snyder

Reports

An Ecological Monitoring Program (EMP) has been established at the Virginia Institute of Marine Science Eastern Shore Laboratory (VIMS ESL) for the coastal environment near the Wachapreague lab. The goals of the initiative are to 1) provide status and trends information to scientists who study and regulators who manage Virginia’s marine resources, 2) provide a scientific context for short-term research and grant proposals 3) provide pedagogical enrichment for educators to use in their classes, and 4) build capacity in staff expertise and training of interns and students at VIMS ESL.

The program formalizes and standardizes data collection for a long-term …


Monitoring The Abundance Of American Shad And River Herring In Virginia’S Rivers 2021 Annual Report, Eric J. Hilton, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee Jan 2022

Monitoring The Abundance Of American Shad And River Herring In Virginia’S Rivers 2021 Annual Report, Eric J. Hilton, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee

Reports

This report describes the results of the twenty-fourth year of a continuing study to estimate the relative abundance and assess the status of American shad (Alosa sapidissima) stocks in Virginia by monitoring the spawning runs in the James, York and Rappahannock rivers in spring 2021, evaluating hatchery programs, and contributing to coast-wide assessments (ASMFC 2007, ASMFC 2020).

We also report on two fishery independent monitoring programs using anchor gillnets in the Rappahannock River (year 4) and the Chickahominy River (year 7; a major tributary of the James River), to determine relative abundance and stock structure for the adult spawning run …


Monitoring The Abundance Of American Shad And River Herring In Virginia’S Rivers 2022 Annual Report, Eric J. Hilton, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee Jan 2022

Monitoring The Abundance Of American Shad And River Herring In Virginia’S Rivers 2022 Annual Report, Eric J. Hilton, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee

Reports

This report describes the results of a continuing study to estimate the relative abundance and assess the status of American shad (Alosa sapidissima) stocks in Virginia by monitoring the spawning runs in the James, York and Rappahannock rivers in spring 2022, evaluating hatchery programs and contributing to coast-wide assessments (ASMFC 2007a; ASMFC 2020). We also report on a fishery-independent monitoring program to determine abundance and stock structure of river herring (A. pseudoharengus, and A. aestivalis) in Virginia by evaluating the adult spawning runs in the Chickahominy River, a major tributary of the James River, and the Rappahannock River. Further, a …


The Role Of Zooplankton Community Composition In Fecal Pellet Carbon Production In The York River Estuary, Chesapeake Bay, Kristen Nicole Sharpe Jan 2022

The Role Of Zooplankton Community Composition In Fecal Pellet Carbon Production In The York River Estuary, Chesapeake Bay, Kristen Nicole Sharpe

Dissertations, Theses, and Masters Projects

The biological pump is a critical component of carbon transformation in aquatic ecosystems, but the role that zooplankton play in carbon production and vertical export is rarely studied in estuaries. Zooplankton produce carbon-rich fecal pellets which sink to depth and can fuel benthic community metabolism. The body size and taxonomic structure of the zooplankton community varies on interannual, seasonal, and diel time scales, and can lead to varying carbon production and export rates. We quantified fecal pellet carbon (FPC) production by the whole mesozooplankton community (> 200 µm) in the York River, a sub-estuary of Chesapeake Bay. Biomass and taxonomic …


Nutrient Function Over Form: Organic And Inorganic Nitrogen Additions Have Similar Effects On Lake Phytoplankton Nutrient Limitation, Sabrina N. Volponi, Heather L. Wander, (...), Brian S. Kim, Et Al Jan 2022

Nutrient Function Over Form: Organic And Inorganic Nitrogen Additions Have Similar Effects On Lake Phytoplankton Nutrient Limitation, Sabrina N. Volponi, Heather L. Wander, (...), Brian S. Kim, Et Al

VIMS Articles

The concentration of dissolved organic nitrogen (DON) is increasing in many northern hemisphere lakes, yet its use by phytoplankton and fate in the environment seldom have been quantified. We conducted 1 week, insitu, microcosm incubations across 25 lakes in northeastern North America to understand how DON, dissolved norganic nitrogen (DIN), and dissolved inorganic phosphorus (P) affected phytoplankton biomass. In addition,we tested whether lakes were limited by single macronutrients (N or P) or colimited by both. Phytoplankton biomass in 80% of lakes responded similarly to DON and DIN additions. Of the lakes where N form produced differential responses, the majority of …


Enhancing Assessments Of Blue Carbon Stocks In Marsh Soils Using Bayesian Mixed-Effects Modeling With Spatial Autocorrelation — Proof Of Concept Using Proxy Data, Grace S. Chiu, Molly Mitchell, Julie Herman, Christian Longo, Kate Davis Jan 2022

Enhancing Assessments Of Blue Carbon Stocks In Marsh Soils Using Bayesian Mixed-Effects Modeling With Spatial Autocorrelation — Proof Of Concept Using Proxy Data, Grace S. Chiu, Molly Mitchell, Julie Herman, Christian Longo, Kate Davis

VIMS Articles

Our paper showcases the potential gain in scientific insights about blue carbon stocks (or total organic carbon) when additional rigor, in the form of a spatial autocorrelation component, is formally incorporated into the statistical model for assessing the variability in carbon stocks. Organic carbon stored in marsh soils, or blue carbon (BC), is important for sequestering carbon from the atmosphere. The potential for marshes to store carbon dioxide, mitigating anthropogenic contributions to the atmosphere, makes them a critical conservation target, but efforts have been hampered by the current lack of robust methods for assessing the variability of BC stocks at …


Ecosystem Enriching And Efficient Solar Energy: Exploring The Effects Of Pollinator-Friendly Solar Facilities On Ecosystem Function And Solar Panel Efficiency, Jordan Martin Jan 2022

Ecosystem Enriching And Efficient Solar Energy: Exploring The Effects Of Pollinator-Friendly Solar Facilities On Ecosystem Function And Solar Panel Efficiency, Jordan Martin

Dissertations, Theses, and Masters Projects

As the solar energy industry grows, many hundreds of thousands of acres of land will be transformed into solar panel facilities. With this large change in land use, there is the opportunity to promote biodiversity and support pollinators by using pollinator-friendly management practices at the solar facilities. This paper explores the ecological and economic effects of a pollinator-friendly solar facility compared to a turfgrass solar facility.

I hypothesized that a pollinator-friendly solar facility would be functionally equivalent in pollinator support and overall insect diversity to a pollinator-friendly non-solar field and that both sites would have far greater pollinator support and …


Center For Coastal Resources Management Annual Report 2021, Center For Coastal Resources Management Jan 2022

Center For Coastal Resources Management Annual Report 2021, Center For Coastal Resources Management

Reports

No abstract provided.


From The Subsurface To The Sky: Tracking Groundwater With Drones, Stephanie Wilson Jan 2022

From The Subsurface To The Sky: Tracking Groundwater With Drones, Stephanie Wilson

Reports

Grades: High School Subjects: Earth Science | Physical Science

Determining the inputs of nitrogen to coastal waters from drone based radiometric temperature data.

Topics covered:

  • Technology and radiometric imagery
  • Drones in science
  • Groundwater
  • Nutrients / pollutants
  • Water cycle/ Watersheds


Killer From The Deep!, Tor Mowatt-Larssen Jan 2022

Killer From The Deep!, Tor Mowatt-Larssen

Reports

Grades: 6-12 Subjects: Life Science | Ecology


Explore the deep-sea environment and biological adaptations to living in the deep sea through murder-mystery investigation and graphing activities.


Diel, Seasonal, And Interannual Changes In Coastal Antarctic Zooplankton Community Composition And Trophic Ecology, John A. Conroy Jan 2022

Diel, Seasonal, And Interannual Changes In Coastal Antarctic Zooplankton Community Composition And Trophic Ecology, John A. Conroy

Dissertations, Theses, and Masters Projects

Throughout the ocean, zooplankton transfer energy from primary producers to higher predators and transport carbon from surface waters to depth. The efficiency of these processes depends in part upon the taxonomic composition and trophic ecology of the zooplankton community. Zooplankton species abundance and distribution shifted over recent decades along the West Antarctic Peninsula during a period of rapid regional warming and sea-ice decline. Although conducted within the context of long-term change, this dissertation research focuses on zooplankton dynamics at finer temporal scales that have received less attention. I analyzed depth-stratified net samples to investigate zooplankton diel vertical migration during Antarctic …


Virginia Seafood Sustainability, Samantha E. Askin, Robert A. Fisher Oct 2021

Virginia Seafood Sustainability, Samantha E. Askin, Robert A. Fisher

Reports

Virginia’s commercial fisheries operate sustainability under a suite of management tools based upon information received from marine scientists and fishery managers who regularly conduct biological sampling of fish while tracking commercial landings and other gathering of required information. Analyses of fishing effort and overall stock conditions, as well as formulas designed to calculate threshold limits for maintaining sustainable stocks are regularly performed. Restrictions on seasons, size, days at sea, and gear are imposed as needed to achieve management supporting long-term biological sustainability.


Estuarine Microbiomes And Biogeochemistry: Impacts Of Spatiotemporal Variation, Algal Blooms, And Microplastics, Samantha Grace Fortin Jul 2021

Estuarine Microbiomes And Biogeochemistry: Impacts Of Spatiotemporal Variation, Algal Blooms, And Microplastics, Samantha Grace Fortin

Dissertations, Theses, and Masters Projects

Estuaries are biogeochemical hotspots connecting terrestrial and coastal ecosystems. Anthropogenic disturbances, including increased nitrogen loading and plastic pollution, may have significant impacts on estuarine carbon and nitrogen cycling by altering microbiome structure and functions. The overarching goal of this dissertation was to examine how microbiomes and their associated biogeochemical processes are influenced by natural variation and anthropogenic disturbances in the York River Estuary (YRE). In chapter 2, spatial and temporal variation in benthic microbiomes and the rates of denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) were examined to determine biotic and abiotic drivers of nitrogen …