Scholarly Works, Biological Sciences

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Near-term ecological forecasting for climate change action
Dietze, Michael; White, Ethan P.; Abeyta, Antoinette; Boettiger, Carl; Bueno Watts, Nievita; Carey, Cayelan C.; Chaplin-Kramer, Rebecca; Emanuel, Ryan E.; Ernest, S. K. Morgan; Figueiredo, Renato J.; Gerst, Michael D.; Johnson, Leah R.; Kenney, Melissa A.; McLachlan, Jason S.; Paschalidis, Ioannis Ch.; Peters, Jody A.; Rollinson, Christine R.; Simonis, Juniper; Sullivan-Wiley, Kira; Thomas, R. Quinn; Wardle, Glenda M.; Willson, Alyssa M.; Zwart, Jacob (Springer Nature, 2024-11-08)
A substantial increase in predictive capacity is needed to anticipate and mitigate the widespread change in ecosystems and their services in the face of climate and biodiversity crises. In this era of accelerating change, we cannot rely on historical patterns or focus primarily on long-term projections that extend decades into the future. In this Perspective, we discuss the potential of near-term (daily to decadal) iterative ecological forecasting to improve decision-making on actionable time frames. We summarize the current status of ecological forecasting and focus on how to scale up, build on lessons from weather forecasting, and take advantage of recent technological advances. We also highlight the need to focus on equity, workforce development, and broad cross-disciplinary and non-academic partnerships.
First evidence of microplastic inhalation among free-ranging small cetaceans
Dziobak, Miranda K.; Fahlman, Andreas; Wells, Randall S.; Takeshita, Ryan; Smith, Cynthia; Gray, Austin D.; Weinstein, John; Hart, Leslie B. (Public Library of Science, 2024-10-16)
Plastic is a ubiquitous environmental contaminant, resulting in widespread exposure across terrestrial and marine spaces. In the environment, plastics can degrade into microparticles where exposure has been documented in a variety of fauna at all trophic levels. Human epidemiological studies have found relationships between inhaled microplastics and oxidative stress and inflammation. Previous studies of bottlenose dolphins (Tursiops truncatus) have reported prevalent exposure to plasticizing chemicals (e.g., phthalates) as well as particle loads in gastrointestinal tracts, but exposure from inhalation has not yet been studied. The objective of this study was to determine if inhalation is a viable route of microplastic exposure for free-ranging dolphins. Exhalation samples were opportunistically collected from dolphins residing in Sarasota Bay, Florida (n = 5) and Barataria Bay, Louisiana (n = 6) during catch-and-release health assessments to screen for microplastic particles. All dolphin samples contained at least one suspected microplastic particle, and polymer composition was determined for 100% of a subset (n = 17) of samples. Additional studies are warranted to better understand the extent of inhaled microplastics, as well as to explore impacts, given potential risks to lung function and health.
The Amphibian Genomics Consortium: advancing genomic and genetic resources for amphibian research and conservation
Kosch, Tiffany A.; Torres-Sánchez, María; Liedtke, H. C.; Summers, Kyle; Yun, Maximina H.; Crawford, Andrew J.; Maddock, Simon T.; Ahammed, Md. S.; Araújo, Victor L. N.; Bertola, Lorenzo V.; Bucciarelli, Gary M.; Carné, Albert; Carneiro, Céline M.; Chan, Kin O.; Chen, Ying; Crottini, Angelica; da Silva, Jessica M.; Denton, Robert D.; Dittrich, Carolin; Espregueira Themudo, Gonçalo; Farquharson, Katherine A.; Forsdick, Natalie J.; Gilbert, Edward; Che, Jing; Katzenback, Barbara A.; Kotharambath, Ramachandran; Levis, Nicholas A.; Márquez, Roberto; Mazepa, Glib; Mulder, Kevin P.; Müller, Hendrik; O’Connell, Mary J.; Orozco-terWengel, Pablo; Palomar, Gemma; Petzold, Alice; Pfennig, David W.; Pfennig, Karin S.; Reichert, Michael S.; Robert, Jacques; Scherz, Mark D.; Siu-Ting, Karen; Snead, Anthony A.; Stöck, Matthias; Stuckert, Adam M. M.; Stynoski, Jennifer L.; Tarvin, Rebecca D.; Wollenberg Valero, Katharina C. (2024-11-01)
Amphibians represent a diverse group of tetrapods, marked by deep divergence times between their three systematic orders and families. Studying amphibian biology through the genomics lens increases our understanding of the features of this animal class and that of other terrestrial vertebrates. The need for amphibian genomic resources is more urgent than ever due to the increasing threats to this group. Amphibians are one of the most imperiled taxonomic groups, with approximately 41% of species threatened with extinction due to habitat loss, changes in land use patterns, disease, climate change, and their synergistic effects. Amphibian genomic resources have provided a better understanding of ontogenetic diversity, tissue regeneration, diverse life history and reproductive modes, anti-predator strategies, and resilience and adaptive responses. They also serve as essential models for studying broad genomic traits, such as evolutionary genome expansions and contractions, as they exhibit the widest range of genome sizes among all animal taxa and possess multiple mechanisms of genetic sex determination. Despite these features, genome sequencing of amphibians has significantly lagged behind that of other vertebrates, primarily due to the challenges of assembling their large, repeat-rich genomes and the relative lack of societal support. The emergence of long-read sequencing technologies, combined with advanced molecular and computational techniques that improve scaffolding and reduce computational workloads, is now making it possible to address some of these challenges. To promote and accelerate the production and use of amphibian genomics research through international coordination and collaboration, we launched the Amphibian Genomics Consortium (AGC, https://mvs.unimelb.edu.au/amphibian-genomics-consortium ) in early 2023. This burgeoning community already has more than 282 members from 41 countries. The AGC aims to leverage the diverse capabilities of its members to advance genomic resources for amphibians and bridge the implementation gap between biologists, bioinformaticians, and conservation practitioners. Here we evaluate the state of the field of amphibian genomics, highlight previous studies, present challenges to overcome, and call on the research and conservation communities to unite as part of the AGC to enable amphibian genomics research to “leap” to the next level.
Detection, Isolation and Quantification of Myocardial Infarct with Four Different Histological Staining Techniques
Wu, Xiaobo; Meier, Linnea; Liu, Tom X.; Toldo, Stefano; Poelzing, Steven; Gourdie, Robert G. (MDPI, 2024-10-18)
Background/Objectives: The precise quantification of myocardial infarction is crucial for evaluating therapeutic strategies. We developed a robust, color-based semi-automatic algorithm capable of infarct region detection, isolation and quantification with four different histological staining techniques, and of the isolation and quantification of diffuse fibrosis in the heart. Methods: Our method is developed based on the color difference in the infarct and non-infarct regions after histological staining. Mouse cardiac tissues stained with Masson’s trichrome (MTS), hematoxylin and eosin (H&E), 2,3,5-Triphenyltetrazolium chloride and picrosirius red were included to demonstrate the performance of our method. Results: We demonstrate that our algorithm can effectively identify and produce a clear visualization of infarct tissue in the four staining techniques. Notably, the infarct region on an H&E-stained tissue section can be clearly visualized after processing. The MATLAB-based program we developed holds promise for infarct quantification. Additionally, our program can isolate and quantify diffuse fibrotic elements from an MTS-stained cardiac section, which suggests the algorithm’s potential for evaluating pathological cardiac fibrosis in diseased cardiac tissues. Conclusions: We demonstrate that this color-based algorithm is capable of accurately identifying, isolating and quantifying cardiac infarct regions with different staining techniques, as well as diffuse and patchy fibrosis in MTS-stained cardiac tissues.
Limitations of trait‐based approaches for stressor assessment: The case of freshwater invertebrates and climate drivers
Hamilton, Anna T.; Schäfer, Ralf B.; Pyne, Matthew I.; Chessman, Bruce; Kakouei, Karan; Boersma, Kate S.; Verdonschot, Piet F. M.; Verdonschot, Ralf C. M.; Mims, Meryl C.; Khamis, Kieran; Bierwagen, Britta; Stamp, Jen (Wiley, 2019-09)
The appeal of trait-based approaches for assessing environmental vulnerabilities arises from the potential insight they provide into the mechanisms underlying the changes in populations and community structure. Traits can provide ecologically based explanations for observed responses to environmental changes, along with predictive power gained by developing relationships between traits and environmental variables. Despite these potential benefits, questions remain regarding the utility and limitations of these approaches, which we explore focusing on the following questions: (a) How reliable are predictions of biotic responses to changing conditions based on single trait–environment relationships? (b) What factors constrain detection of single trait–environment relationships, and how can they be addressed? (c) Can we use information on meta-community processes to reveal conditions when assumptions underlying trait-based studies are not met? We address these questions by reviewing published literature on aquatic invertebrate communities from stream ecosystems. Our findings help to define factors that influence the successful application of trait-based approaches in addressing the complex, multifaceted effects of changing climate conditions on hydrologic and thermal regimes in stream ecosystems. Key conclusions are that observed relationships between traits and environmental stressors are often inconsistent with predefined hypotheses derived from current trait-based thinking, particularly related to single trait–environment relationships. Factors that can influence findings of trait-based assessments include intercorrelations of among traits and among environmental variables, spatial scale, strength of biotic interactions, intensity of habitat disturbance, degree of abiotic stress, and methods of trait characterization. Several recommendations are made for practice and further study to address these concerns, including using phylogenetic relatedness to address intercorrelation. With proper consideration of these issues, trait-based assessment of organismal vulnerability to environmental changes can become a useful tool to conserve threatened populations into the future.
A modular curriculum to teach undergraduates ecological forecasting improves student and instructor confidence in their data science skills
Lofton, Mary E.; Moore, Tadhg N.; Woelmer, Whitney M.; Thomas, R. Quinn; Carey, Cayelan C. (Oxford University Press, 2024-10-10)
Data science skills (e.g., analyzing, modeling, and visualizing large data sets) are increasingly needed by undergraduates in the life sciences. However, a lack of both student and instructor confidence in data science skills presents a barrier to their inclusion in undergraduate curricula. To reduce this barrier, we developed four teaching modules in the Macrosystems EDDIE (for environmental data-driven inquiry and exploration) program to introduce undergraduate students and instructors to ecological forecasting, an emerging subdiscipline that integrates multiple data science skills. Ecological forecasting aims to improve natural resource management by providing future predictions of ecosystems with uncertainty. We assessed module efficacy with 596 students and 26 instructors over 3 years and found that module completion increased students’ confidence in their understanding of ecological forecasting and instructors’ likelihood to work with long-term, high-frequency sensor network data. Our modules constitute one of the first formalized data science curricula on ecological forecasting for undergraduates.
Surface hydrophilicity promotes bacterial twitching motility
O'Hara, Megan T.; Shimozono, Tori M.; Dye, Keane J.; Harris, David; Yang, Zhaomin (American Society for Microbiology, 2024-08-28)
Twitching motility is a form of bacterial surface translocation powered by the type IV pilus (T4P). It is frequently analyzed by interstitial colony expansion between agar and the polystyrene surfaces of petri dishes. In such assays, the twitching motility of Acinetobacter nosocomialis was observed with MacConkey but not Luria-Bertani (LB) agar media. One difference between these two media is the presence of bile salts as a selective agent in MacConkey but not in LB. Here, we demonstrate that the addition of bile salts to LB allowed A. nosocomialis to display twitching. Similarly, bile salts enhanced the twitching of Acinetobacter baumannii and Pseudomonas aeruginosa in LB. These observations suggest that there is a common mechanism, whereby bile salts enhance bacterial twitching and promote interstitial colony expansion. Bile salts disrupt lipid membranes and apply envelope stress as detergents. Surprisingly, their stimulatory effect on twitching appears not to be related to a bacterial physiological response to stressors. Rather, it is due to their ability to alter the physicochemical properties of a twitching surface. We observed that while other detergents promoted twitching like bile salts, stresses applied by antibiotics, including the outer membrane-targeting polymyxin B, did not enhance twitching motility. More importantly, bacteria displayed increased twitching on hydrophilic surfaces such as those of glass and tissue culture-treated polystyrene plastics, and bile salts no longer stimulated twitching on these surfaces. Together, our results show that altering the hydrophilicity of a twitching surface significantly impacts T4P functionality.
Geochemical drivers of manganese removal in drinking water reservoirs under hypolimnetic oxygenation
Ming, Cissy L.; Breef-Pilz, Adrienne; Howard, Dexter W.; Schreiber, Madeline E. (Elsevier, 2024-07)
Manganese (Mn) is a naturally occurring contaminant commonly found in drinking water supplies. In lakes and reservoirs, water authorities increasingly use in situ treatment by hypolimnetic oxygenation (HOx) systems to remove metals such as Mn from the water column. HOx systems introduce dissolved oxygen (DO) to the bottom waters (hypolimnion) to promote oxidation and subsequent removal of metals from the water column. Previous laboratory studies have shown the importance of individual geochemical drivers (pH, alkalinity, mineral surfaces) on Mn oxidation, but few studies have examined the influence of these drivers of Mn removal in concert. In this study, we conducted field monitoring and laboratory experiments to examine how pH, alkalinity and the presence of mineral particles influence Mn removal at two drinking water reservoirs in southwest Virginia, both with HOx systems: Falling Creek Reservoir (FCR) and Carvins Cove Reservoir (CCR). Both reservoirs have had historical issues with elevated (>0.05 mg/L) Mn concentrations during seasonal stratification (May–October). Watershed geology contributes to differences in pH and alkalinity between the reservoirs, with FCR having lower historical medians of hypolimnetic pH and alkalinity (6.6 and 18 mg/L CaCO₃, respectively) than CCR (7.2 and 62 mg/L CaCO₃, respectively). Results of laboratory experiments examining the influence of pH on Mn removal showed substantial Mn loss within 14 days only under high pH (10) conditions. Mn removal did not occur at pH 6 or 8 over the same 14-day period. In experiments with pH 10 and alkalinity >70 mg/L CaCO₃, near-total Mn removal occurred within 2 h. Mn removal occurred concurrently with precipitation of microscopic (<5 μm) particles, followed by formation of macroscopic (>100 μm) particles. Particles of both size classes were identified as Mn oxides (MnOx). These observations suggest that increasing pH and alkalinity promotes Mn oxidation and subsequent removal from solution. Results of experiments with pH 10 and alkalinity >70 mg/L CaCO₃ suggest that heterogeneous oxidation by MnOx partially drives rapid Mn removal. Thus, initial formation of MnOx creates a positive feedback loop that can enhance additional Mn loss. In experiments using water collected from FCR and CCR, we observed rapid Mn removal in unfiltered water (0.002–0.05 d⁻¹) but no significant removal of Mn in filtered water. These results, in combination with results of analysis of particles collected from reservoir water, suggest that minerals present in the water column likely catalyze MnOx formation. Together, our experimental results suggest that heterogenous oxidation is an important process of Mn removal, while pH and alkalinity variations of the range expected in natural freshwaters contribute less to differential Mn removal. The formation of MnOx particles during in situ oxygenation, as well as the presence of suspended minerals that occur naturally in water columns, play an important role in promoting Mn oxidation and should be accounted for in Mn removal treatment strategies.
Response of a Terrestrial Polar Ecosystem to the March 2022 Antarctic Weather Anomaly
Barrett, John E.; Adams, Byron J.; Doran, Peter T.; Dugan, Hilary A.; Myers, Krista F.; Salvatore, Mark R.; Power, Sarah N.; Snyder, Meredith D.; Wright, Anna T.; Gooseff, Michael N. (American Geophysical Union, 2024-07-31)
Record high temperatures were documented in the McMurdo Dry Valleys, Antarctica, on 18 March 2022, exceeding average temperatures for that day by nearly 30°C. Satellite imagery and stream gage measurements indicate that surface wetting coincided with this warming more than 2 months after peak summer thaw and likely exceeded thresholds for rehydration and activation of resident organisms that typically survive the cold and dry conditions of the polar fall in a freeze‐dried state. This weather event is notable in both the timing and magnitude of the warming and wetting when temperatures exceeded 0°C at a time when biological communities and streams have typically entered a persistent frozen state. Such events may be a harbinger of future climate conditions characterized by warmer temperatures and greater thaw in this region of Antarctica, which could influence the distribution, activity, and abundance of sentinel taxa. Here we describe the ecosystem responses to this weather anomaly reporting on meteorological and hydrological measurements across the region and on later biological observations from Canada Stream, one of the most diverse and productive ecosystems within the McMurdo Dry Valleys.
Widespread exposure to SARS-CoV-2 in wildlife communities
Goldberg, Amanda R.; Langwig, Kate E.; Brown, Katherine L.; Marano, Jeffrey M.; Rai, Pallavi; King, Kelsie M.; Sharp, Amanda K.; Ceci, Alessandro; Kailing, Christopher D.; Kailing, Macy J.; Briggs, Russell; Urbano, Matthew G.; Roby, Clinton; Brown, Anne M.; Weger-Lucarelli, James; Finkielstein, Carla V.; Hoyt, Joseph R. (Springer, 2024-07-29)
Pervasive SARS-CoV-2 infections in humans have led to multiple transmission events to animals. While SARS-CoV-2 has a potential broad wildlife host range, most documented infections have been in captive animals and a single wildlife species, the white-tailed deer. The full extent of SARS-CoV-2 exposure among wildlife communities and the factors that influence wildlife transmission risk remain unknown. We sampled 23 species of wildlife for SARS-CoV-2 and examined the effects of urbanization and human use on seropositivity. Here, we document positive detections of SARS-CoV-2 RNA in six species, including the deer mouse, Virginia opossum, raccoon, groundhog, Eastern cottontail, and Eastern red bat between May 2022–September 2023 across Virginia and Washington, D.C., USA. In addition, we found that sites with high human activity had three times higher seroprevalence than low human-use areas. We obtained SARS-CoV-2 genomic sequences from nine individuals of six species which were assigned to seven Pango lineages of the Omicron variant. The close match to variants circulating in humans at the time suggests at least seven recent human-to-animal transmission events. Our data support that exposure to SARS-CoV-2 has been widespread in wildlife communities and suggests that areas with high human activity may serve as points of contact for cross-species transmission.
Flipped Science Fair Invites Children to Judge Graduate Student Posters Through a University-Community Partnership
Lewis, Abigail L.; O’Malley, Grace; Palissery, Gates K.; Hensley, Amanda; Lloreda, Carla López; Perez, Claudia; Bueren, Emma K. (Vanderbilt University Library, 2023-10-03)
Flipped Science Fairs put power directly into children’s hands, inviting them to judge graduate student science fair posters. At the fair, graduate students practice communicating their research to a young audience, while children have the opportunity to see themselves as valued contributors in science. Here, we present a model for a walk-in Flipped Science Fair, designed in partnership between nine Virginia Tech graduate students and the Roanoke City Public Libraries (RPL; Roanoke, VA, USA). At our event, 27 graduate students presented posters about their research, with an audience of over 250 community members. We found that hosting the Flipped Science Fair at a public library lowered barriers to entry for participants and allowed us to reach an audience further from the university. While judging posters, children learned about a wide range of leading-edge research and had meaningful interactions with diverse scientists in small-group settings. Conversely, for graduate students, this event and associated training workshops provided an opportunity to practice communicating their research to a new audience. Throughout this article, we share our experience as graduate students collaboratively conceptualizing and organizing this community-oriented Flipped Science Fair with public library partners.
A naturally derived biomaterial formulation for improved menstrual care
Bataglioli, Rogerio Aparecido; Kaur, Harsimran; Muller, John; Geddes, Elizabeth; Champine, Carrie; Hsu, Bryan B. (Cell Press, 2024-07-10)
Adequately managing menstruation is an important factor in the overall quality of life for women. With a growing discussion of the global need for its improvement, it is clear that better management of menstruation can positively influence social, educational, and professional outcomes. Herein, we describe a biopolymer-based formulation that gels blood in a mechanism alternative to coagulation. We first tested several biopolymer mixtures with blood and quantified increases in viscosity, finding that high-molecular-weight alginate in combination with glycerol could rapidly absorb and gel blood. We then demonstrated that this powder could be deployed both as a traditional menstrual pad filler and as an additive to menstrual cups to reduce leakage and spillage, respectively. Finally, we include an antimicrobial polymer to impair the growth of Staphylococcus aureus, a bacterium associated with toxic shock syndrome. Collectively, our work describes a biodegradable formulation derived from renewable resources that can improve menstrual care.
History of the Development of Knowledge about the Neuroendocrine Control of Ovulation—Recent Knowledge on the Molecular Background
Szabó, Flóra; Köves, Katalin; Gál, Levente (MDPI, 2024-06-13)
The physiology of reproduction has been of interest to researchers for centuries. The purpose of this work is to review the development of our knowledge on the neuroendocrine background of the regulation of ovulation. We first describe the development of the pituitary gland, the structure of the median eminence (ME), the connection between the hypothalamus and the pituitary gland, the ovarian and pituitary hormones involved in ovulation, and the pituitary cell composition. We recall the pioneer physiological and morphological investigations that drove development forward. The description of the supraoptic–paraventricular magnocellular and tuberoinfundibular parvocellular systems and recognizing the role of the hypophysiotropic area were major milestones in understanding the anatomical and physiological basis of reproduction. The discovery of releasing and inhibiting hormones, the significance of pulse and surge generators, the pulsatile secretion of the gonadotropin-releasing hormone (GnRH), and the subsequent pulsatility of luteinizing (LH) and follicle-stimulating hormones (FSH) in the human reproductive physiology were truly transformative. The roles of three critical neuropeptides, kisspeptin (KP), neurokinin B (NKB), and dynorphin (Dy), were also identified. This review also touches on the endocrine background of human infertility and assisted fertilization.
Vibrio cholerae Bacteremia: An Enigma in Cholera-Endemic African Countries
Agyei, Foster K.; Scharf, Birgit; Duodu, Samuel (MDPI, 2024-05-02)
Cholera is highly endemic in many sub-Saharan African countries. The bacterium Vibrio cholerae is responsible for this severe dehydrating diarrheal disease that accounts for over 100,000 deaths each year globally. In recent years, the pathogen has been found to invade intestinal layers and translocate into the bloodstream of humans. The non-toxigenic strains of V. cholerae (non-O1/O139), also known as NOVC, which do not cause epidemic or pandemic cases of cholera, are the major culprits of V. cholerae bacteremia. In non-cholera-endemic regions, clinical reports on NOVC infection have been noted over the past few decades, particularly in Europe and America. Although low–middle-income countries are most susceptible to cholera infections because of challenges with access to clean water and inappropriate sanitation issues, just a few cases of V. cholerae bloodstream infections have been reported. The lack of evidence-based research and surveillance of V. cholerae bacteremia in Africa may have significant clinical implications. This commentary summarizes the existing knowledge on the host risk factors, pathogenesis, and diagnostics of NOVC bacteremia.
Spatial extent drives patterns of relative climate change sensitivity for freshwater fishes of the United States
Silknetter, Samuel C.; Benson, Abigail L.; Smith, Jennifer A.; Mims, Meryl C. (Wiley, 2024-03)
Assessing the sensitivity of freshwater species to climate change is an essential component of prioritizing conservation efforts for threatened freshwater ecosystems and organisms. Sensitivity to climate change can be systematically evaluated for multiple species using geographic attributes such as range size and climate niche breadth, and using species traits associated with climate change sensitivity. These systematic evaluations produce relative rankings of species sensitivity to aid conservation prioritization and to identify relatively sensitive species that may otherwise be understudied or overlooked. Due in part to biogeographic constraints, species assemblages change across regions and spatial extents; yet, the degree to which spatial factors influence relative rankings of species sensitivity is unclear. The spatial extent of multispecies analyses may alter relative rankings of species climate sensitivity; alternatively, relative climate sensitivity may be conserved among spatial scales, resulting in consistent identification of sensitive species among regions and spatial extents. We investigated how spatial extent influences our understanding of relative climate sensitivity for 137 native freshwater fishes of the United States that were representative of taxonomic, trait, and geographic diversity. Using publicly available occurrence data from the Global Biodiversity Information Facility, we calculated a systematic, geographically derived index of climate change sensitivity for study species at national and regional extents, including within four major hydrologic subregions of the United States. We examined the effects of spatial extent on the relative ranking of climate sensitivity among species, and we explored relationships among climate sensitivity, species traits, and conservation status at regional and national extents. We found that climate sensitivity rankings of species were influenced by spatial extent in some specific instances, but that relative rankings were largely conserved across spatial scales. However, correlations among geographically derived climate sensitivity rankings and species traits associated with climate sensitivity were variable across scales and regions, suggesting that links between geographic rarity and species traits may be scale-dependent in some cases. Finally, we found few associations between climate sensitivity and current conservation status among species. Systematic approaches to quantifying climate sensitivity may offer an opportunity to identify sensitive but overlooked species for pre-listing actions such as monitoring or conservation agreements.
Using Water Quality as a Proxy to Estimate Microplastic Concentrations in the New River, VA, via Sentinel 2
Rodriguez Sequeira, Luisana; Allen, George H.; Gray, Austin D. (New River Symposium, 2024-04-12)
Microplastics (<5mm), are pervasive in Earth’s environments, and rivers are a major transport pathway. Microplastic detection methods that rely on counting individual particles are time consuming and require laborious field collection, inhibiting real-time insights over large spatial extents, which are needed in order to better understand the issue. Satellite remote sensing has been used to estimate water quality in rivers with relatively high spatial and temporal coverage. Finding a correlation between water quality and microplastics could allow us to estimate microplastics in rivers via satellite imagery using water quality as a proxy. Though a handful of these assessments have been done, a wide-variety of study sites are needed to form a coherent model. We focused our study in the New River near Blacksburg, VA, and collected weekly water quality measurements and surface-water microplastic samples. We combined these in situ measurements with cotemporal remotely-sensed water quality index observations from Sentinel-2 to develop a model estimating microplastic concentration. We validated the model using in-situ spectrometry and water quality measurements. By providing more observations than what can be done with in situ sampling alone, we can improve large-scale microplastic analyses and modeling leading to better assessments of mismanaged plastic waste in Earth’s rivers.
A silent spring, or a new cacophony? Invasive plants as maestros of modern soundscapes
Barney, Jacob N.; O'Malley, Grace; Ripa, Gabrielle N.; Drake, Joseph; Franusich, David; Mims, Meryl C. (Wiley, 2024-04-01)
Sound plays a key role in ecosystem function and is a defining part of how humans experience nature. In the seminal book Silent Spring (Carson 1962), Rachel Carson warned of the ecological and environmental harm of pesticide usage by envisioning a future without birdsong. Soundscapes, or the acoustic patterns of a landscape through space and time, encompass both biological and physical processes (Pijanowski et al. 2011). Yet, they are often an underappreciated element of the natural world and the ways in which it is perceived. Scientists are only beginning to quantify changes to soundscapes, largely in response to anthropogenic sounds, but soundscape alteration is likely linked to many dimensions of global change. For example, invasive non-native species (hereafter, invasive species) are near-ubiquitous members of ecosystems globally and threaten both natural and managed ecosystems at great expense. Their impacts to soundscapes may be an important, yet largely unknown, threat to ecosystems and the human and economic systems they support.
Altered DNA methylation underlies monocyte dysregulation and immune exhaustion memory in sepsis
Caldwell, Blake A.; Wu, Yajun; Wang, Jing; Li, Liwu (Elsevier, 2024-03)
Monocytes can develop an exhausted memory state characterized by reduced differentiation, pathogenic inflammation, and immune suppression that drives immune dysregulation during sepsis. Chromatin alterations, notably via histone modifications, underlie innate immune memory, but the contribution of DNA methylation remains poorly understood. Using an ex vivo sepsis model, we show altered DNA methylation throughout the genome of exhausted monocytes, including genes implicated in immune dysregulation during sepsis and COVID-19 infection (e.g., Plac8). These changes are recapitulated in septic mice induced by cecal slurry injection. Methylation profiles developed in septic mice are maintained during ex vivo culture, supporting the involvement of DNA methylation in stable monocyte exhaustion memory. Methylome reprogramming is driven in part by Wnt signaling inhibition in exhausted monocytes and can be reversed with DNA methyltransferase inhibitors, Wnt agonists, or immune training molecules. Our study demonstrates the significance of altered DNA methylation in the maintenance of stable monocyte exhaustion memory.
Coordination of rhythmic RNA synthesis and degradation orchestrates 24-and 12-h RNA expression patterns in mouse fibroblasts
Unruh, Benjamin A.; Weidemann, Douglas E.; Miao, Lin; Kojima, Shihoko (National Academy of Sciences, 2024)
Circadian RNA expression is essential to ultimately regulate a plethora of downstream rhythmic biochemical, physiological, and behavioral processes. Both transcriptional and posttranscriptional mechanisms are considered important to drive rhythmic RNA expression; however, the extent to which each regulatory process contributes to the rhythmic RNA expression remains controversial. To systematically address this, we monitored RNA dynamics using metabolic RNA labeling technology during a circadian cycle in mouse fibroblasts. We find that rhythmic RNA synthesis is the primary contributor of 24-h RNA rhythms, while rhythmic degradation is more important for 12-h RNA rhythms. These rhythms were predominantly regulated by Bmal1 and/or the core clock mechanism, and the interplay between rhythmic synthesis and degradation has a significant impact in shaping rhythmic RNA expression patterns. Interestingly, core clock RNAs are regulated by multiple rhythmic processes and have the highest amplitude of synthesis and degradation, presumably critical to sustain robust rhythmicity of cell-autonomous circadian rhythms. Our study yields invaluable insights into the temporal dynamics of both 24-and 12-h RNA rhythms in mouse fibroblasts.
Can Common Pool Resource Theory Catalyze Stakeholder-Driven Solutions to the Freshwater Salinization Syndrome?
Grant, Stanley B.; Rippy, Megan A.; Birkland, Thomas A.; Schenk, Todd; Rowles, Kristin; Misra, Shalini; Aminpour, Payam; Kaushal, Sujay; Vikesland, Peter J.; Berglund, Emily; Gomez-Velez, Jesus D.; Hotchkiss, Erin R.; Perez, Gabriel; Zhang, Harry X.; Armstrong, Kingston; Bhide, Shantanu V.; Krauss, Lauren; Maas, Carly; Mendoza, Kent; Shipman, Caitlin; Zhang, Yadong; Zhong, Yinman (American Chemical Society, 2022-09-14)
Freshwater salinity is rising across many regions of the United States as well as globally, a phenomenon called the freshwater salinization syndrome (FSS). The FSS mobilizes organic carbon, nutrients, heavy metals, and other contaminants sequestered in soils and freshwater sediments, alters the structures and functions of soils, streams, and riparian ecosystems, threatens drinking water supplies, and undermines progress toward many of the United Nations Sustainable Development Goals. There is an urgent need to leverage the current understanding of salinization's causes and consequences?in partnership with engineers, social scientists, policymakers, and other stakeholders?into locally tailored approaches for balancing our nation's salt budget. In this feature, we propose that the FSS can be understood as a common pool resource problem and explore Nobel Laureate Elinor Ostrom's social-ecological systems framework as an approach for identifying the conditions under which local actors may work collectively to manage the FSS in the absence of top-down regulatory controls. We adopt as a case study rising sodium concentrations in the Occoquan Reservoir, a critical water supply for up to one million residents in Northern Virginia (USA), to illustrate emerging impacts, underlying causes, possible solutions, and critical research needs.

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