Department of Earth and Environmental Sciences Works

Permanent URI for this collection

https://hdl.handle.net/1805/5814

Browse

Now showing 1 - 10 of 346

Multiple sulfur isotopes fractionations associated with abiotic sulfur transformations in Yellowstone National Park geothermal springs
(Springer Nature, 2014-05-28) Kamyshny, Alexey, Jr.; Druschel, Gregory; Mansaray, Zahra F.; Farquhar, James; Earth and Environmental Sciences, School of Science
Background: The paper presents a quantification of main (hydrogen sulfide and sulfate), as well as of intermediate sulfur species (zero-valent sulfur (ZVS), thiosulfate, sulfite, thiocyanate) in the Yellowstone National Park (YNP) hydrothermal springs and pools. We combined these measurements with the measurements of quadruple sulfur isotope composition of sulfate, hydrogen sulfide and zero-valent sulfur. The main goal of this research is to understand multiple sulfur isotope fractionation in the system, which is dominated by complex, mostly abiotic, sulfur cycling. Results: Water samples from six springs and pools in the Yellowstone National Park were characterized by pH, chloride to sulfate ratios, sulfide and intermediate sulfur species concentrations. Concentrations of sulfate in pools indicate either oxidation of sulfide by mixing of deep parent water with shallow oxic water, or surface oxidation of sulfide with atmospheric oxygen. Thiosulfate concentrations are low (<6 μmol L(-1)) in the pools with low pH due to fast disproportionation of thiosulfate. In the pools with higher pH, the concentration of thiosulfate varies, depending on different geochemical pathways of thiosulfate formation. The δ(34)S values of sulfate in four systems were close to those calculated using a mixing line of the model based on dilution and boiling of a deep hot parent water body. In two pools δ(34)S values of sulfate varied significantly from the values calculated from this model. Sulfur isotope fractionation between ZVS and hydrogen sulfide was close to zero at pH < 4. At higher pH zero-valent sulfur is slightly heavier than hydrogen sulfide due to equilibration in the rhombic sulfur-polysulfide - hydrogen sulfide system. Triple sulfur isotope ((32)S, (33)S, (34)S) fractionation patterns in waters of hydrothermal pools are more consistent with redox processes involving intermediate sulfur species than with bacterial sulfate reduction. Small but resolved differences in ∆(33)S among species and between pools are observed. Conclusions: The variation of sulfate isotopic composition, the origin of differences in isotopic composition of sulfide and zero-valent sulfur, as well as differences in ∆(33)S of sulfide and sulfate are likely due to a complex network of abiotic redox reactions, including disproportionation pathways.
Involvement of Intermediate Sulfur Species in Biological Reduction of Elemental Sulfur under Acidic, Hydrothermal Conditions
(American Society for Microbiology, 2013) Boyd, Eric S.; Druschel, Gregory K.; Earth and Environmental Sciences, School of Science
The thermoacidophile and obligate elemental sulfur (S(8)(0))-reducing anaerobe Acidilobus sulfurireducens 18D70 does not associate with bulk solid-phase sulfur during S(8)(0)-dependent batch culture growth. Cyclic voltammetry indicated the production of hydrogen sulfide (H(2)S) as well as polysulfides after 1 day of batch growth of the organism at pH 3.0 and 81°C. The production of polysulfide is likely due to the abiotic reaction between S(8)(0) and the biologically produced H(2)S, as evinced by a rapid cessation of polysulfide formation when the growth temperature was decreased, inhibiting the biological production of sulfide. After an additional 5 days of growth, nanoparticulate S(8)(0) was detected in the cultivation medium, a result of the hydrolysis of polysulfides in acidic medium. To examine whether soluble polysulfides and/or nanoparticulate S(8)(0) can serve as terminal electron acceptors (TEA) supporting the growth of A. sulfurireducens, total sulfide concentration and cell density were monitored in batch cultures with S(8)(0) provided as a solid phase in the medium or with S(8)(0) sequestered in dialysis tubing. The rates of sulfide production in 7-day-old cultures with S(8)(0) sequestered in dialysis tubing with pore sizes of 12 to 14 kDa and 6 to 8 kDa were 55% and 22%, respectively, of that of cultures with S(8)(0) provided as a solid phase in the medium. These results indicate that the TEA existed in a range of particle sizes that affected its ability to diffuse through dialysis tubing of different pore sizes. Dynamic light scattering revealed that S(8)(0) particles generated through polysulfide rapidly grew in size, a rate which was influenced by the pH of the medium and the presence of organic carbon. Thus, S(8)(0) particles formed through abiological hydrolysis of polysulfide under acidic conditions appeared to serve as a growth-promoting TEA for A. sulfurireducens.
Essential Teamwork Skills: Perspectives of Environmental Geoscience Employers
(TechRxiv, 2022) Nyarko, Samuel Cornelius; Petcovic, Heather L.
Geoscience employers have increasingly called for the future workforce (students) to demonstrate competence in non-technical skills, including teamwork. This descriptive qualitative study contributes to ongoing efforts to identify the specific practices, skills, habits, and knowledge that make up these desired teamwork competencies in the geosciences. We collected interview data from three online focus group discussions centered around teamwork. Focus group participants (n = 12) were hydrogeology and environmental geology employers and team managers from government, private industry, and nonprofit organizations in the United States. Using a teamwork skills taxonomy model as our conceptual framework, we coded the transcripts to generate three categories of teamwork skills specific to environmental geoscience teams. First, our data indicate that these employers value team transition skills related to specifying goals, interpreting team tasks, identifying resources, and planning. The second category of desired teamwork competencies included action skills such as metacognition, coordination, and mentoring. These skills directly impact successful task completion. The third category captured interpersonal skills such as emotional intelligence, proactive communication, and organization. A fourth category of desired teamwork competencies emerged from data analysis and include ethical skills related to trust, integrity, and humility. This study provides a detailed description of teamwork competencies desired by environmental geoscience employers. We recommend that geoscience instructors consider using techniques such as intentional teaching of teamwork skills, experiential learning, professional development, and teamwork awareness in order to prepare students for workforce expectations.
Measurement in STEM education research: a systematic literature review of trends in the psychometric evidence of scales
(Springer, 2023) Maric, Danka; Fore, Grant A.; Nyarko, Samuel Cornelius; Varma‑Nelson, Pratibha
Background: The objective of this systematic review is to identify characteristics, trends, and gaps in measurement in Science, Technology, Engineering, and Mathematics (STEM) education research. Methods: We searched across several peer-reviewed sources, including a book, similar systematic reviews, conference proceedings, one online repository, and four databases that index the major STEM education research journals. We included empirical studies that reported on psychometric development of scales developed on college/university students for the context of post-secondary STEM education in the US. We excluded studies examining scales that ask about specific content knowledge and contain less than three items. Results were synthesized using descriptive statistics. Results: Our final sample included the total number of N = 82 scales across N = 72 studies. Participants in the sampled studies were majority female and White, most scales were developed in an unspecified STEM/science and engineering context, and the most frequently measured construct was attitudes. Internal structure validity emerged as the most prominent validity evidence, with exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) being the most common. Reliability evidence was dominated by internal consistency evidence in the form of Cronbach’s alpha, with other forms being scarcely reported, if at all. Discussion: Limitations include only focusing on scales developed in the United States and in post-secondary contexts, limiting the scope of the systematic review. Our findings demonstrate that when developing scales for STEM education research, many types of psychometric properties, such as differential item functioning, test–retest reliability, and discriminant validity are scarcely reported. Furthermore, many scales only report internal structure validity (EFA and/or CFA) and Cronbach’s alpha, which are not enough evidence alone. We encourage researchers to look towards the full spectrum of psychometric evidence both when choosing scales to use and when developing their own. While constructs such as attitudes and disciplines such as engineering were dominant in our sample, future work can fill in the gaps by developing scales for disciplines, such as geosciences, and examine constructs, such as engagement, self-efficacy, and perceived fit.
K-12 trade books’ representation of earthquake safety and protective actions: A content analysis
(Wiley, 2024) Nyarko, Samuel Cornelius; Sumy, Danielle F.; McBride, Sara K.
Meaningful learning resources for earthquake safety and survival have become an increasingly important topic among geoscientists, especially educators and researchers. Various members of the public, especially K-12 (ages 5–18) learners, continue to depend on scientific trade books available at their local public and school libraries for information about earthquake concepts. To our knowledge, no research has empirically examined how trade books represent earthquake safety and survival actions. In this research, we combine an iterative qualitative inductive and deductive analysis to explore the representation of earthquake safety and protective actions in 50 trade books. We categorize these actions into time-based practices related to preparedness before an earthquake, protective actions during an earthquake, and recovery after an earthquake. These trade books emphasize preparedness by means of building earthquake-resistant structures and urban planning, and efforts toward community resilience and keeping home supplies. The recommended personal protective action during an earthquake in the United States (“Drop, Cover, and Hold On”) is emphasized in the majority of the trade books, as well as other protective actions related to emotional actions and current technological automated actions such as earthquake early warning systems. Finally, the books highlight actions such as damage evaluation and support as ways to recover after an earthquake. Our findings highlight the issues between accepted earthquake safety and survival actions and the limited and/or inaccurate knowledge represented in some trade books. We provide interpretations of how presentation of limited or inaccurate information may increase confusion about appropriate protective actions. The inclusion of accepted and recommended protective actions in future trade books and the use of earthquake drills in public libraries as a supplement for trade book users may improve understanding and implementation of appropriate actions. We further demonstrate the potential of trade book contents in fostering earthquake education through library-community partnerships.
Geoscience Education Perspectives on Integrated, Coordinated, Open, Networked (ICON) Science
(Wiley, 2022) Fortner, Sarah K.; Manduca, Cathryn A.; Ali, Hendratta N.; Saup, Casey M.; Nyarko, Samuel Cornelius; Othus-Gault, Shannon; Perera, Viranga; Tong, Vincent C. H.; Gold, Anne U.; Furman, Tanya; Arthurs, Leilani; Mulvey, Bridget K.; St. John, Kristen; Singley, Joel G.; Johnson, Elijah Thomas; Witter, Molly; Batchelor, Rebecca L.; Carter, Deron T.; Damas, M. Chantale; LeMay, Lynsey; Layou, Karen M.; Low, Russanne; Wang, Hui Hui; Olson-Sawyer, Kai; Pallant, Amy; Ryker, Katherine; Lukes, Laura; LaDue, Nicole; Ryker, Katherine; van der Hoeven Kraft, Kaatje J.
Practitioners and researchers in geoscience education embrace collaboration applying ICON (Integrated, Coordinated, Open science, and Networked) principles and approaches which have been used to create and share large collections of educational resources, to move forward collective priorities, and to foster peer-learning among educators. These strategies can also support the advancement of coproduction between geoscientists and diverse communities. For this reason, many authors from the geoscience education community have co-created three commentaries on the use and future of ICON in geoscience education. We envision that sharing our expertise with ICON practice will be useful to other geoscience communities seeking to strengthen collaboration. Geoscience education brings substantial expertise in social science research and its application to building individual and collective capacity to address earth sustainability and equity issues at local to global scales The geoscience education community has expanded its own ICON capacity through access to and use of shared resources and research findings, enhancing data sharing and publication, and leadership development. We prioritize continued use of ICON principles to develop effective and inclusive communities that increase equity in geoscience education and beyond, support leadership and full participation of systemically non-dominant groups and enable global discussions and collaborations.
Global synthesis of cover crop impacts on main crop yield
(Elsevier, 2024-04-15) Peng, Yu; Wang, Lixin; Jacinthe, Pierre-André; Ren, Wei; Earth Science, School of Science
Incorporating cover crops into farming systems represents a potential pathway to maintaining crop productivity and achieving multiple environmental benefits. However, how cover crops impact the succeeding crop yield remained a matter of debate. Therefore, this study aims to provide a comprehensive and global scale assessment of cover crop impacts on yield. We conducted a literature synthesis of cover crop studies (104 articles) to collect field-based yield data (1027 records) and used meta-analysis to quantify the impact of cover crops on subsequent main crop yields. Our results showed that cover cropping led to an overall moderate increase in main crop yield, amounting to 2.6%. Specifically, the utilization of leguminous cover crops, cultivation in coarse soil texture and dryland areas, and the implementation of longer cover cropping durations were found to be conducive scenarios to enhance crop yields. Conversely, the use of non-legume cover crops, introducing them to fields under a short-term no-till, especially in fine-textured soils, were impaired to yields. Leguminous cover crops showed the greatest potential for increasing yield (9.8%) particularly when paired with corn. Adopting leguminous cover crops without fertilizing main crops resulted in a 21.8% yield increase. Utilizing cover crops did not affect yield if the field had already under no-till practice. Introducing cover crops on coarser soils and in rainfed drylands can increase yield by 14.1% and 11.4%, respectively. In fine-textured soils, cover crop plus conventional tillage achieved 4.8% yield increase while cover crops plus no-tillage led to a 9.5% yield decrease instead. Consequently, our findings suggested the general yield profitability of cover crops, but substantial variations remain, which was primarily affected by availability of nitrogen and soil moisture. It is advisable to maximize the nitrogen-fixing capability of leguminous cover crops as a nitrogen source for main crops, replacing fertilizer. Particular attention should be paid, and additional management practices should be adopted when using cover crops plus no-tillage in fine-textured soils to avoid yield penalties. These specific supportive measures are suggested to shorten the lag period of yield increase within the initial 1–3 years of cover cropping implementation. Our synthesis quantified the overall cover crop impacts on yield, showcasing variable yield returns across different scenarios. This holistic understanding and comprehensive information can serve to advance the appropriate and targeted adoption of cover crops by policymakers, extension services, and farmers.
Assessing variability of optimum air temperature for photosynthesis across site-years, sites and biomes and their effects on photosynthesis estimation
(Elsevier, 2021) Chang, Qing; Xiao, Xiangming; Doughty, Russell; Wu, Xiaocui; Jiao, Wenzhe; Qin, Yuanwei; Earth and Environmental Sciences, School of Science
Gross primary productivity (GPP) of vegetation is affected by air temperature. Biogeochemical models use the optimum air temperature (Topt) parameter, which comes from biome-specific look-up tables (Topt−b−LT). Many studies have shown that plants have the capacity to adapt to changes in environmental conditions over time, which suggests that the static Topt−b−LT parameters in the biogeochemical models may poorly represent actual Topt and induce uncertainty in GPP estimates. Here, we estimated biome-specific, site-year-specific, and site-specific optimum air temperature using GPP data from eddy covariance (EC) flux tower sites (GPPEC) (Topt−b−EC, Topt−sy−EC, Topt−s−EC), the Enhanced Vegetation Index (EVI) from MODIS images (Topt−b−EVI, Topt−sy−EVI, Topt−s−EVI), and mean daytime air temperature (TDT). We evaluated the consistency among the four Topt parameters (Topt−b, Topt−sy, Topt−s and Topt−b−LT), and assessed how they affect satellite-based GPP estimates. We find that Topt parameters from MODIS EVI agree well with those from GPPEC, which indicates that EVI can be used as a variable to estimate Topt at individual pixels over large spatial domains. Topt−b, Topt−sy, and Topt−s differed significantly from Topt−b−LT. GPP estimates using Topt−b and Topt−sy were more consistent with GPPEC than when using Topt−b−LT for all the land cover types. Our use of Topt−sy substantially improved 8-day and annual GPP estimates across biomess (from 1% to 34%), especially for cropland, grassland, and open shrubland. Our simple calculation shows that global GPP estimates differ by up to 10 Pg C/yr when using our suggested Topt−sy−EVI instead of using the static Topt−b−LT. Our new approach on estimating Topt has the potential to improve estimates of GPP from satellite-based models, which could lead to better understanding of carbon-climate interactions.
Effect of short-term exposure to air pollution on daily cardio- and cerebrovascular hospitalisations in areas with a low level of air pollution
(Springer, 2023) Hasnain, Md Golam; Garcia‑Esperon, Carlos; Tomari, Yumi Kashida; Walker, Rhonda; Saluja, Tarunpreet; Rahman, Md Mijanur; Boyle, Andrew; Levi, Christopher R.; Naidu, Ravi; Filippelli, Gabriel; Spratt, Neil J.; Earth and Environmental Sciences, School of Science
Exposure to air pollution is associated with increased cardio- and cerebrovascular diseases. However, the evidence regarding the short-term effect of air pollution on cardio- and cerebrovascular hospitalisations in areas with relatively low air pollution levels is limited. This study aims to examine the effect of short-term exposure to different air pollutants on hospital admissions due to cardio- and cerebrovascular diseases in rural and regional Australia with low air pollution. The study was conducted in five local Government areas of Hunter New England Local Health District (HNE-LHD). Hospitalisation data from January 2018 to February 2020 (820 days) were accessed from the HNE-LHD admitted patients' dataset. Poisson regression model was used to examine the association between the exposure (air pollutants) and outcome variables (hospitalisation due to cardio- and cerebrovascular disease). The concentrations of gaseous air pollutants, Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Ozone (O3), Carbon Monoxide (CO), and Ammonia (NH3) were below national benchmark concentrations for every day of the study period. In single pollutant models, SO2 and NO2 significantly increased the daily number of cardio- and cerebrovascular hospitalisations. The highest cumulative effect for SO2 was observed across lag 0-3 days (Incidence Rate Ratio, IRR: 1.77; 95% Confidence Interval, CI: 1.18-2.65; p-value: 0.01), and for NO2, it was across lag 0-2 days (IRR: 1.13; 95% CI: 1.02-1.25; p-value: 0.02). In contrast, higher O3 was associated with decreased cardio- and cerebrovascular hospitalisations, with the largest effect observed at lag 0 (IRR: 0.94; 95% CI: 0.89-0.98; p-value: 0.02). In the multi-pollutant model, the effect of NO2 remained significant at lag 0 and corresponded to a 21% increase in cardio- and cerebrovascular hospitalisation (95% CI: 1-44%; p-value = 0.04). Thus, the study revealed that gaseous air pollutants, specifically NO2, were positively related to increased cardio- and cerebrovascular hospitalisations, even at concentrations below the national standards.
Predictive modeling of indoor dust lead concentrations: Sources, risks, and benefits of intervention
(Elsevier, 2023) Dietrich, Matthew; Barlow, Cynthia F.; Entwistle, Jane A.; Meza-Figueroa, Diana; Dong, Chenyin; Gunkel-Grillon, Peggy; Jabeen, Khadija; Bramwell, Lindsay; Shukle, John T.; Wood, Leah R.; Naidu, Ravi; Fry, Kara; Taylor, Mark Patrick; Filippelli, Gabriel M.; Earth and Environmental Sciences, School of Science
Lead (Pb) contamination continues to contribute to world-wide morbidity in all countries, particularly low- and middle-income countries. Despite its continued widespread adverse effects on global populations, particularly children, accurate prediction of elevated household dust Pb and the potential implications of simple, low-cost household interventions at national and global scales have been lacking. A global dataset (∼40 countries, n = 1951) of community sourced household dust samples were used to predict whether indoor dust was elevated in Pb, expanding on recent work in the United States (U.S.). Binned housing age category alone was a significant (p < 0.01) predictor of elevated dust Pb, but only generated effective predictive accuracy for England and Australia (sensitivity of ∼80%), similar to previous results in the U.S. This likely reflects comparable Pb pollution legacies between these three countries, particularly with residential Pb paint. The heterogeneity associated with Pb pollution at a global scale complicates the predictive accuracy of our model, which is lower for countries outside England, the U.S., and Australia. This is likely due to differing environmental Pb regulations, sources, and the paucity of dust samples available outside of these three countries. In England, the U.S., and Australia, simple, low-cost household intervention strategies such as vacuuming and wet mopping could conservatively save 70 billion USD within a four-year period based on our model. Globally, up to 1.68 trillion USD could be saved with improved predictive modeling and primary intervention to reduce harmful exposure to Pb dust sources.

Browse

Recent Submissions