Life Sciences Commons^™

Epidemic Time Series Similarity Is Related To Geographic Distance And Age Structure, Tad Dallas, Grant Foster, Robert L. Richards, Bret D. Elderd

Faculty Publications

Objective

More similar locations may have similar infectious disease dynamics. There is clear overlap in putative causes for epidemic similarity, such as geographic distance, age structure, and population size. We compare the effects of these potential drivers on epidemic similarity compared to a baseline assumption that differences in the basic reproductive number (R₀) will translate to differences in epidemic trajectories.

Methods

Using COVID-19 case counts from United States counties, we explore the importance of geographic distance, population size differences, and age structure dissimilarity on resulting epidemic similarity.

Results

We find clear effects of geographic space, age structure, …

Insectdisease: Programmatic Access To The Ecological Database Of The World’S Insect Pathogens, Tad Dallas, Colin J. Carlson, Patrick R. Stephens, Sadie J. Ryan, David W. Onstad

Faculty Publications

Curated databases of species interactions are instrumental to exploring and understanding the spatial distribution of species and their biotic interactions. In the process of conducting such projects, data development and curation efforts may give rise to a data product with utility beyond the scope of the original work, but which becomes inaccessible over time. Data describing insect host–pathogen interactions are fairly rare, and should thus be preserved and curated with appropriate metadata. Here, we introduce the insectDisease R package, a mechanism for curating, updating and distributing data from the Ecological Database of the World's Insect Pathogens, a database of insect …

A Latitudinal Signal In The Relationship Between Species Geographic Range Size And Climatic Niche Area, Tad Dallas, Andrew Kramer

Faculty Publications

Species with broader niches may have the opportunity to occupy larger geographic areas, assuming no limitations on dispersal and a relatively homogeneous environmental space. Here, we use data on a large set of mammal (n = 1225), bird (n = 1829) and tree (n = 341) species to examine the 1) relationship between geographic range size and climatic niche area, 2) influence of species traits on species departures from this relationship and 3) sensitivity of these relationships to how species range size and climatic niche area are estimated. We find positive geographic range size–climatic niche area relationships for all taxa, …

Estimating R0 From Early Exponential Growth: Parallels Between 1918 Influenza And 2020 Sars-Cov-2 Pandemics, Grant Foster, Bret D. Elderd, Robert L. Richards, Tad Dallas

Faculty Publications

The large spatial scale, geographical overlap, and similarities in transmission mode between the 1918 H1N1 influenza and 2020 SARS-CoV-2 pandemics together provide a novel opportunity to investigate relationships between transmission of two different diseases in the same location. To this end, we use initial exponential growth rates in a Bayesian hierarchical framework to estimate the basic reproductive number, R₀, of both disease outbreaks in a common set of 43 cities in the United States. By leveraging multiple epidemic time series across a large spatial area, we are able to better characterize the variation in R₀ across the …

The Marine Gastropod Conomurex Luhuanus (Strombidae) Has High-Resolution Spatial Vision And Eyes With Complex Retinas, Allison R. Irwin, Suzanne T. Williams, Daniel Isaac Speiser, Nicholas W. Roberts

Faculty Publications

All species within the conch snail family Strombidae possess large camera-type eyes that are surprisingly well-developed compared with those found in most other gastropods. Although these eyes are known to be structurally complex, very little research on their visual function has been conducted. Here, we use isoluminant expanding visual stimuli to measure the spatial resolution and contrast sensitivity of a strombid, Conomurex luhuanus. Using these stimuli, we show that this species responds to objects as small as 1.06 deg in its visual field. We also show that C. luhuanus responds to Michelson contrasts of 0.07, a low contrast sensitivity …

Snapping Shrimp Have Helmets That Protect Their Brains By Dampening Shock Waves, Alexandra C.N. Kingston, Sarah A. Woodin, David S. Wethey, Daniel Isaac Speiser

Faculty Publications

Shock waves are supersonic high-amplitude pressure waves that cause barotrauma when they transfer kinetic energy to the tissues of animals.1, 2, 3, 4 Snapping shrimp (Alpheidae) produce shock waves and are exposed to them frequently, so we asked if these animals have evolved mechanisms of physical protection against them. Snapping shrimp generate shock waves by closing their snapping claws rapidly enough to form cavitation bubbles that release energy as an audible “snap” and a shock wave when they collapse.5, 6, 7, 8 We tested if snapping shrimp are protected from shock waves …

Optimising Predictive Models To Prioritise Viral Discovery In Zoonotic Reservoirs, Daniel J. Becker, Gregory F. Albery, Anna R. Sjodin, Timothée Poisot, Laura M. Bergner, Binqi Chen, Lily E. Cohen, Tad Dallas, Evan A. Eskew, Anna C. Fagre, Maxwell J. Farrell, Sarah Guth, Barbara A. Han, Nancy B. Simmons, Michiel Stock, Emma C. Teeling, Colin J. Carlson

Faculty Publications

Despite the global investment in One Health disease surveillance, it remains difficult and costly to identify and monitor the wildlife reservoirs of novel zoonotic viruses. Statistical models can guide sampling target prioritisation, but the predictions from any given model might be highly uncertain; moreover, systematic model validation is rare, and the drivers of model performance are consequently under-documented. Here, we use the bat hosts of betacoronaviruses as a case study for the data-driven process of comparing and validating predictive models of probable reservoir hosts. In early 2020, we generated an ensemble of eight statistical models that predicted host–virus associations and …

Post-Embryonic Phase Transitions Mediated By Polycomb Repressive Complexes In Plants, Valerie Hinsch, Samuel Adkins, Darren Manuela, Mingli Xu

Faculty Publications

Correct timing of developmental phase transitions is critical for the survival and fitness of plants. Developmental phase transitions in plants are partially promoted by controlling relevant genes into active or repressive status. Polycomb Repressive Complex1 (PRC1) and PRC2, originally identified in Drosophila, are essential in initiating and/or maintaining genes in repressive status to mediate developmental phase transitions. Our review summarizes mechanisms in which the embryo-to-seedling transition, the juvenile-to-adult transition, and vegetative-to-reproductive transition in plants are mediated by PRC1 and PRC2, and suggests that PRC1 could act either before or after PRC2, or that they could function independently of each other. …

Leaf Development In Medicago Truncatula, Liren Du, Samuel Winright Adkins, Mingli Xu

Faculty Publications

Forage yield is largely dependent on leaf development, during which the number of leaves, leaflets, leaf size, and shape are determined. In this mini-review, we briefly summarize recent studies of leaf development in Medicago truncatula, a model plant for legumes, with a focus on factors that could affect biomass of leaves. These include: floral development and related genes, lateral organ boundary genes, auxin biosynthesis, transportation and signaling genes, and WOX related genes.

Pickle Associates With Histone Deacetylase 9 To Mediate Vegetative Phase Change In Arabidopsis, Tieqiang Hu, Darren Manuela, Valerie Hinsch, Mingli Xu

Faculty Publications

The juvenile-to-adult vegetative phase change in flowering plants is mediated by a decrease in miR156 levels. Downregulation of MIR156A/MIR156C, the two major sources of miR156, is accompanied by a decrease in acetylation of histone 3 lysine 27 (H3K27ac) and an increase in trimethylation of H3K27 (H3K27me3) at MIR156A/MIR156C in Arabidopsis. Here, we show that histone deacetylase 9 (HDA9) is recruited to MIR156A/MIR156C during the juvenile phase and associates with the CHD3 chromatin remodeler PICKLE (PKL) to erase H3K27ac at MIR156A/MIR156C.H2Aub and H3K27me3 become enriched at MIR156A/MIR156C, and the recruitment of Polycomb Repressive Complex 2 (PRC2) to MIR156A/MIR156C is partially dependent …

Pickle Associates With Histone Deacetylase 9 To Mediate Vegetative Phase Change In Arabidopsis, Tieqiang Hu, Darren Manuela, Valerie Hinsch, Mingli Xu

Faculty Publications

• The juvenile-to-adult vegetative phase change in flowering plants is mediated by a decrease in miR156 levels. Downregulation of MIR156A/MIR156C, the two major sources of miR156, is accompanied by a decrease in acetylation of histone 3 lysine 27 (H3K27ac) and an increase in trimethylation of H3K27 (H3K27me3) at MIR156A/MIR156C in Arabidopsis.

• Here, we show that histone deacetylase 9 (HDA9) is recruited to MIR156A/MIR156C during the juvenile phase and associates with the CHD3 chromatin remodeler PICKLE (PKL) to erase H3K27ac at MIR156A/MIR156C.

• H2Aub and H3K27me3 become enriched at MIR156A/MIR156C, and the recruitment of Polycomb Repressive Complex …

The Interplay Between Hydrogen Sulfide And Phytohormone Signaling Pathways Under Challenging Environments, Muhammad Saad Shoaib Khan, Faisal Islam, Yajin Ye, Matthew Ashline, Daowen Wang, Biying Zhao, Zheng Qing Fu, Jian Chen

Faculty Publications

Hydrogen sulfide (H₂S) serves as an important gaseous signaling molecule that is involved in intra- and intercellular signal transduction in plant–environment interactions. In plants, H₂S is formed in sulfate/cysteine reduction pathways. The activation of endogenous H₂S and its exogenous application has been found to be highly effective in ameliorating a wide variety of stress conditions in plants. The H₂S interferes with the cellular redox regulatory network and prevents the degradation of proteins from oxidative stress via post-translational modifications (PTMs). H₂S-mediated persulfidation allows the rapid response of proteins in signaling networks …

The Global Virome In One Network (Virion): An Atlas Of Vertebrate-Virus Associations, Colin J. Carlson, Rory J. Gibb, Gregory F. Albery, Liam Brierley, Ryan P. Connor, Tad Dallas, Evan A. Eskew, Anna C. Fagre, Maxwell J. Farrell, Hannah K. Frank, Renata L. Muylaert, Timothée Poisot, Angela L. Rasmussen, Sadie J. Ryan, Stephanie N. Seifert

Faculty Publications

Data that catalogue viral diversity on Earth have been fragmented across sources, disciplines, formats, and various degrees of open sharing, posing challenges for research on macroecology, evolution, and public health. Here, we solve this problem by establishing a dynamically maintained database of vertebrate-virus associations, called The Global Virome in One Network (VIRION). The VIRION database has been assembled through both reconciliation of static data sets and integration of dynamically updated databases. These data sources are all harmonized against one taxonomic backbone, including metadata on host and virus taxonomic validity and higher classification; additional metadata on sampling methodology and evidence strength …

The Global Virome In One Network (Virion): An Atlas Of Vertebrate-Virus Associations, Colin J. Carlson, Rory J. Gibb, Gregory F. Albery, Liam Brierley, Ryan P. Connor, Tad Dallas, Evan A. Eskew, Anna C. Fagre, Maxwell J. Farrell, Hannah K. Frank, Renata L. Muylaert, Timothée Poisot, Angela L. Rasmussen, Sadie J. Ryan, Stephanie N. Seifert

Faculty Publications

Data that catalogue viral diversity on Earth have been fragmented across sources, disciplines, formats, and various degrees of open sharing, posing challenges for research on macroecology, evolution, and public health. Here, we solve this problem by establishing a dynamically maintained database of vertebrate-virus associations, called The Global Virome in One Network (VIRION). The VIRION database has been assembled through both reconciliation of static data sets and integration of dynamically updated databases. These data sources are all harmonized against one taxonomic backbone, including metadata on host and virus taxonomic validity and higher classification; additional metadata on sampling methodology and evidence strength …

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 …

Transcriptional Coactivators: Driving Force Of Plant Immunity, Muhammad Saad Shoaib Khan, Faisal Islam, Huan Chen, Ming Chang, Daowen Wang, Fengquan Liu, Zhengqing Fu, Jian Chen

Faculty Publications

Salicylic acid (SA) is a plant defense signal that mediates local and systemic immune responses against pathogen invasion. However, the underlying mechanism of SA-mediated defense is very complex due to the involvement of various positive and negative regulators to fine-tune its signaling in diverse pathosystems. Upon pathogen infections, elevated level of SA promotes massive transcriptional reprogramming in which Non-expresser of PR genes 1 (NPR1) acts as a central hub and transcriptional coactivator in defense responses. Recent findings show that Enhanced Disease Susceptibility 1 (EDS1) also functions as a transcriptional coactivator and stimulates the expression of PR1 in the presence of …

Improved Chromosome-Level Genome Assembly Of The Glanville Fritillary Butterfly (Melitaea Cinxia) Integrating Pacific Biosciences Long Reads And A High-Density Linkage Map, Olli-Pekka Smolander, Daniel Blande, Virpi Ahola, Pasi Rastas, Jaakko Tanskanen, Juhana Kammonen, Vicencio Oostra, Lorenzo Pellegrini, Suvi Ikonen, Tad Dallas, Michelle F. Dileo, Anne Duplouy, Iihan Cem Duru, Pauliina Halimaa, Aapo Kahilainen, Suyog S. Kuwar, Sirpa O. Kärenlampi, Elvira Lafuente, Shiqi Luo, Jenny Makkonen, Abhilash Nair, Narua De La Paz Celorio-Mancera, Ville Pennanen, Annukka Ruokolainen, Tarja Sundell, Arja I. Tervahauta, Victoria Twort, Erik Van Bergen, Janina Österman-Udd, Lars Paulin, Mikko J. Frilander, Petri Auvinen, Marjo Saastamoinen

Faculty Publications

Background

The Glanville fritillary (Melitaea cinxia) butterfly is a model system for metapopulation dynamics research in fragmented landscapes. Here, we provide a chromosome-level assembly of the butterfly's genome produced from Pacific Biosciences sequencing of a pool of males, combined with a linkage map from population crosses.

Results

The final assembly size of 484 Mb is an increase of 94 Mb on the previously published genome. Estimation of the completeness of the genome with BUSCO indicates that the genome contains 92–94% of the BUSCO genes in complete and single copies. We predicted 14,810 genes using the MAKER pipeline and …

Panoramic Spatial Vision In The Bay Scallop Argopecten Irradians, Daniel R. Chappell, Tyler M. Horan, Daniel Isaac Speiser

Faculty Publications

We have a growing understanding of the light-sensing organs and light-influenced behaviours of animals with distributed visual systems, but we have yet to learn how these animals convert visual input into behavioural output. It has been suggested they consolidate visual information early in their sensory-motor pathways, resulting in them being able to detect visual cues (spatial resolution) without being able to locate them (spatial vision). To explore how an animal with dozens of eyes processes visual information, we analysed the responses of the bay scallop Argopecten irradians to both static and rotating visual stimuli. We found A. irradians distinguish between …

Low Light Intensity Delays Vegetative Phase Change, Mingli Xu, Tieqiang Hu, R Scott Poethig

Faculty Publications

Plants that develop under low light (LL) intensity often display a phenotype known as the “shade tolerance syndrome (STS)”. This syndrome is similar to the phenotype of plants in the juvenile phase of shoot development, but the basis for this similarity is unknown. We tested the hypothesis that the STS is regulated by the same mechanism that regulates the juvenile vegetative phase by examining the effect of LL on rosette development in Arabidopsis (Arabidopsis thaliana). We found that LL prolonged the juvenile vegetative phase and that this was associated with an increase in the expression of the master …

The Ghost Of Hosts Past: Impacts Of Host Extinction On Parasite Specificity, Maxwell J. Farrell, Andrew W. Park, Clayton E. Cressler, Tad Dallas, Shan Huang, Nicole Mideo, Ignacio Morales-Castilla, T. Jonathan Davies, Patrick Stephens

Faculty Publications

A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites across the host phylogeny can have knock-on effects that may reshape the adaptation of both hosts and parasites, ultimately shifting the evolutionary landscape underlying the potential for emergence and the evolution of virulence across hosts. Here, we examine how the reshaping of host phylogenies through extinction may …

The Future Of Zoonotic Risk Prediction, Colin J. Carlson, Maxwell J. Farrell, Zoe Grange, Barbara A. Han, Nardus Mollentze, Alexandra L. Phelan, Angela L. Rasmussen, Gregory F. Albery, Bernard Bett, David M. Brett-Major, Lily E. Cohen, Tad Dallas, Evan A. Eskew, Anna C. Fagre, Kristian M. Forbes, Rory Gibb, Sam Halabi, Charlotte C. Hammer, Rebecca Katz, Jason Kindrachuk, Renata L. Muylaert, Felicia B. Nutter, Joseph Ogola, Kevin J. Olival, Michelle Rourke, Sadie J. Ryan, Noam Ross, Stephanie N. Seifert, Tarja Sironen, Claire J. Standley, Kishana Taylor, Marietjie Venter, Paul W. Webala

Faculty Publications

In the light of the urgency raised by the COVID-19 pandemic, global investment in wildlife virology is likely to increase, and new surveillance programmes will identify hundreds of novel viruses that might someday pose a threat to humans. To support the extensive task of laboratory characterization, scientists may increasingly rely on data-driven rubrics or machine learning models that learn from known zoonoses to identify which animal pathogens could someday pose a threat to global health. We synthesize the findings of an interdisciplinary workshop on zoonotic risk technologies to answer the following questions. What are the prerequisites, in terms of open …

The Ghost Of Hosts Past: Impacts Of Host Extinction On Parasite Specificity, Maxwell J. Farrell, Andrew W. Park, Clayton E. Cressler, Tad Dallas, Shan Huang, Nicole Mideo, Ignacio Morales-Castilla, T. Jonathan Davies, Patrick Stephens

Faculty Publications

A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites across the host phylogeny can have knock-on effects that may reshape the adaptation of both hosts and parasites, ultimately shifting the evolutionary landscape underlying the potential for emergence and the evolution of virulence across hosts. Here, we examine how the reshaping of host phylogenies through extinction may …

On The Human Appropriation Of Wetland Primary Production, James A. Cloern, Samuel M. Safran, Lydia Smith Vaughn, April Robinson, Alison A. Whipple, Katharyn E. Boyer, Judith Z. Drexler, Robert J. Naiman, James L. Pinckney, Emily R. Howe, Elizabeth A. Canuel, J. Letitia Grenier

Faculty Publications

Humans are changing the Earth's surface at an accelerating pace, with significant consequences for ecosystems and their biodiversity. Landscape transformation has far-reaching implications including reduced net primary production (NPP) available to support ecosystems, reduced energy supplies to consumers, and disruption of ecosystem services such as carbon storage. Anthropogenic activities have reduced global NPP available to terrestrial ecosystems by nearly 25%, but the loss of NPP from wetland ecosystems is unknown. We used a simple approach to estimate aquatic NPP from measured habitat areas and habitat-specific areal productivity in the largest wetland complex on the USA west coast, comparing historical and …

Local Translation Across Neural Development: A Focus On Radial Glial Cells, Axons, And Synaptogenesis, Manasu Agrawal, Kristy Welshhans

Faculty Publications

In the past two decades, significant progress has been made in our understanding of mRNA localization and translation at distal sites in axons and dendrites. The existing literature shows that local translation is regulated in a temporally and spatially restricted manner and is critical throughout embryonic and post-embryonic life. Here, recent key findings about mRNA localization and local translation across the various stages of neural development, including neurogenesis, axon development, and synaptogenesis, are reviewed. In the early stages of development, mRNAs are localized and locally translated in the endfeet of radial glial cells, but much is still unexplored about their …

Comparable Response Of Wild Rodent Gut Microbiome To Anthropogenic Habitat Contamination, Anton Lavrinienko, Ann Hämäläinen, Rasmus Hindstrom, Eugene Tukalenko, Zbyszek Boratynski, Kati Kivisaari, Timothy Mousseau, Phillip C. Watts, Tapio Mappes

Faculty Publications

Species identity is thought to dominate over environment in shaping wild rodent gut microbiota, but it remains unknown whether the responses of host gut microbiota to shared anthropogenic habitat impacts are species-specific or if the general gut microbiota response is similar across host species. Here, we compare the influence of exposure to radionuclide contamination on the gut microbiota of four wild mouse species: Apodemus flavicollis, A. sylvaticus, A. speciosus and A. argenteus. Building on the evidence that radiation impacts bank vole (Myodes glareolus) gut microbiota, we hypothesized that radiation exposure has a general impact on rodent gut microbiota. Because we …

What Is Refractory Organic Matter In The Ocean?, Federico Baltar, Xosé A. Alvarez-Salgado, Javier Arístegui, Ronald Benner, Dennis A. Hansell, Gerhard J. Herndl, Christian Lønborg

Faculty Publications

About 20% of the organic carbon produced in the sunlit surface ocean is transported into the ocean’s interior as dissolved, suspended and sinking particles to be mineralized and sequestered as dissolved inorganic carbon (DIC), sedimentary particulate organic carbon (POC) or “refractory” dissolved organic carbon (rDOC). Recently, the physical and biological mechanisms associated with the particle pumps have been revisited, suggesting that accepted fluxes might be severely underestimated (Boyd et al., 2019; Buesseler et al., 2020). Perhaps even more poorly understood are the mechanisms driving rDOC production and its potential accumulation in the ocean. On the basis of …

Activating Mutations In Braf Disrupt The Hypothalamo-Pituitary Axis Leading To Hypopituitarism In Mice And Humans, Angelica Gualtieri, Nikolina Kyprianou, Louise C. Gregory, Maria Lillina Vignola, James G. Nicholson, Rachael Tan, Shin-Ichi Inoue, Valeria Scagliotti, Pedro Casado, James Blackburn, Fernando Abollo-Jimenez, Eugenia Marinelli, Rachael E.J. Besser, Wolfgang Högler, I. Karen Temple, Justin H. Davies, Andrey Gagunashvili, Iain C.A.F. Robinson, Sally A. Camper, Shannon W. Davis, Pedro R. Cutillas, Evelien F. Gevers, Yoko Aoki, Mehul T. Dattani, Carles Gaston-Massuet

Faculty Publications

Germline mutations in BRAF and other components of the MAPK pathway are associated with the congenital syndromes collectively known as RASopathies. Here, we report the association of Septo-Optic Dysplasia (SOD) including hypopituitarism and Cardio-Facio-Cutaneous (CFC) syndrome in patients harbouring mutations in BRAF. Phosphoproteomic analyses demonstrate that these genetic variants are gain-of-function mutations leading to activation of the MAPK pathway. Activation of the MAPK pathway by conditional expression of the Braf^V600E/+ allele, or the knock-in Braf^Q241R/+ allele (corresponding to the most frequent human CFC-causing mutation, BRAF p.Q257R), leads to abnormal cell lineage determination and terminal differentiation of …

What Is Refractory Organic Matter In The Ocean?, Federico Baltar, Xosé A. Alvarez-Salgado, Javier Arístegui, Ronald Benner, Dennis A. Hansell, Gerhard J. Herndl, Christian Lønborg

Faculty Publications

About 20% of the organic carbon produced in the sunlit surface ocean is transported into the ocean’s interior as dissolved, suspended and sinking particles to be mineralized and sequestered as dissolved inorganic carbon (DIC), sedimentary particulate organic carbon (POC) or “refractory” dissolved organic carbon (rDOC). Recently, the physical and biological mechanisms associated with the particle pumps have been revisited, suggesting that accepted fluxes might be severely underestimated (Boyd et al., 2019; Buesseler et al., 2020). Perhaps even more poorly understood are the mechanisms driving rDOC production and its potential accumulation in the ocean. On the basis of …

What Is Refractory Organic Matter In The Ocean?, Federico Baltar, Xosé A. Alvarez-Salgado, Javier Arístegui, Ronald Benner, Dennis A. Hansell, Gerhard J. Herndl, Christian Lønborg

Faculty Publications

About 20% of the organic carbon produced in the sunlit surface ocean is transported into the ocean’s interior as dissolved, suspended and sinking particles to be mineralized and sequestered as dissolved inorganic carbon (DIC), sedimentary particulate organic carbon (POC) or “refractory” dissolved organic carbon (rDOC). Recently, the physical and biological mechanisms associated with the particle pumps have been revisited, suggesting that accepted fluxes might be severely underestimated (Boyd et al., 2019; Buesseler et al., 2020). Perhaps even more poorly understood are the mechanisms driving rDOC production and its potential accumulation in the ocean. On the basis of …

Protocols For Assessing Transformation Rates Of Nitrous Oxide In The Water Column, Annie Bourbonnais, Claudia Frey, Xin Sun, Laura A. Bristow, Amal Jayakumar, Nathaniel E. Ostrom, Karen L. Casciotti, Bess B. Ward

Faculty Publications

Nitrous oxide (N2O) is a potent greenhouse gas and an ozone destroying substance. Yet, clear step-by-step protocols to measure N2O transformation rates in freshwater and marine environments are still lacking, challenging inter-comparability efforts. Here we present detailed protocols currently used by leading experts in the field to measure water-column N2O production and consumption rates in both marine and other aquatic environments. We present example 15N-tracer incubation experiments in marine environments as well as templates to calculate both N2O production and consumption rates. We discuss important considerations and recommendations regarding (1) precautions to prevent oxygen (O2) contamination during low-oxygen and anoxic …