Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 31 - 40 of 40

Full-Text Articles in Physical Sciences and Mathematics

Effect Of Genotype On The Physicochemical, Nutritional, And Antioxidant Properties Of Hempseed, Youjie Xu, Jikai Zhao, Ruijia Hu, Weiqun Wang, Jason Griffin, Yonghui Li, Xiuzhi Susan Sun, Donghai Wang Mar 2021

Effect Of Genotype On The Physicochemical, Nutritional, And Antioxidant Properties Of Hempseed, Youjie Xu, Jikai Zhao, Ruijia Hu, Weiqun Wang, Jason Griffin, Yonghui Li, Xiuzhi Susan Sun, Donghai Wang

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Hempseed products has been used as nutraceutical supplements and pharmaceutical products. However, hempseed has been underutilized as a food crop for human consumption. To fill the gap of limited knowledge of the variation of hempseed for food consumption, thirteen hemp varieties were selected to evaluate the effect of genotype on the physicochemical, nutritional, and antioxidant properties of hempseed. The tested hempseed contains 26.48–32.03% crude protein with average of 28.48%, 28.03–33.23% crude oil with average of 29.54%, 28.78–36.55% crude fiber with average of 33.49%, and 5.43%–6.32% ash with average of 5.89. Average test weight of 36.85 lbs/bu was relatively low compared …


Environmental Drivers Of Mesophotic Echinoderm Assemblages Of The Southeastern Pacific Ocean, Ariadna Mecho, Boris Dewitte, Javier Sellanes, Simon Van Gennip, Erin E. Easton, Joao B. Gusmao Feb 2021

Environmental Drivers Of Mesophotic Echinoderm Assemblages Of The Southeastern Pacific Ocean, Ariadna Mecho, Boris Dewitte, Javier Sellanes, Simon Van Gennip, Erin E. Easton, Joao B. Gusmao

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Mesophotic ecosystems (50–400 m depth) of the southeastern Pacific have rarely been studied because of the logistical challenges in sampling across this remote zone. This study assessed how oxygen concentrations and other environmental predictors explain variation in echinoderm assemblages at these mesophotic systems, where this group is among the predominant fauna. We compiled data on echinoderm taxa at 91 sampling stations, from historical and recent surveys (between 1950 and 2019), covering a longitudinal gradient of approximately 3,700 km along with the Nazca, Salas y Gómez, and Juan Fernández ridges. Uni- and multivariate model-based tools were applied to analyze the patterns …


Identifying Nitrogen Source And Seasonal Variation In A Black Mangrove (Avicennia Germinans) Communityof The South Texas Coast, Ashley Elizabeth Murphy, Carlos E. Cintra-Buenrostro, Alejandro Fierro-Cabo Feb 2021

Identifying Nitrogen Source And Seasonal Variation In A Black Mangrove (Avicennia Germinans) Communityof The South Texas Coast, Ashley Elizabeth Murphy, Carlos E. Cintra-Buenrostro, Alejandro Fierro-Cabo

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Black mangrove (Avicennia germinans) stands in south Texas grow in association with other autotrophic organisms including herbaceous halophytes and cyanobacterial mats. Despite the relevant ecosystem services provided by this coastal plant community, limited information exists on its functioning, in particular as it pertains to nutrient dynamics, namely nitrogen (N). Nitrogen stable isotopes were used to assess potential N sources for plant growth in this community. Plant tissue (leaves), cyanobacteria, and sediment were sampled once every season for one year. Total N in A. germinans (2.6 %) and associated saltwort (Batis maritima) (2.1 %) was higher than in cyanobacteria (0.6 %), …


Influence Of Land Use Intensity And Management On Arbuscular Mycorrhizal Fungi-Avocado Symbiosis, Pushpa Soti, Bulent Toprak, Nina De La Rosa, Krish Jayachandran Feb 2021

Influence Of Land Use Intensity And Management On Arbuscular Mycorrhizal Fungi-Avocado Symbiosis, Pushpa Soti, Bulent Toprak, Nina De La Rosa, Krish Jayachandran

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

This study was done to assess the effect of soil disturbance on arbuscular mycorrhizal fungi spore abundance and root colonization in avocado (Persea americana Mill.). Rhizosphere soil and root samples of avocado were collected from different farms in south Florida and analyzed for degree of mycorrhizal colonization in roots, spore density and diversity in soil along with soil characteristics. There was significant difference in the soil characteristics among the different farms. Similarly, there was a significant difference in the degree of mycorrhizal colonization in the roots and the arbuscular mycorrhizal fungi spore morphotypes among different land use and management practices. …


Nuclear Niño Response Observed In Simulations Of Nuclear War Scenarios, Joshua Coupe, Samantha Stevenson, Nicole S. Lovenduski, Tyler Rohr, Cheryl S. Harrison, Alan Robock, Holly Olivarez, Charles G. Bardeen, Owen B. Toon Jan 2021

Nuclear Niño Response Observed In Simulations Of Nuclear War Scenarios, Joshua Coupe, Samantha Stevenson, Nicole S. Lovenduski, Tyler Rohr, Cheryl S. Harrison, Alan Robock, Holly Olivarez, Charles G. Bardeen, Owen B. Toon

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

The climate impacts of smoke from fires ignited by nuclear war would include global cooling and crop failure. Facing increased reliance on ocean-based food sources, it is critical to understand the physical and biological state of the post-war oceans. Here we use an Earth system model to simulate six nuclear war scenarios. We show that global cooling can generate a large, sustained response in the equatorial Pacific, resembling an El Niño but persisting for up to seven years. The El Niño following nuclear war, or Nuclear Niño, would be characterized by westerly trade wind anomalies and a shutdown of equatorial …


A Multi-Modal Approach To Measuring Particulate Iron Speciation In Buoyant Hydrothermal Plumes, Brandy D. Stewart, Jeffry V. Sorensen, Kathleen Wendt, Jason B. Sylvan, Christopher R. German, Karthik Anantharaman, Gregory J. Dick, John A. Breier, Brandy M. Toner Jan 2021

A Multi-Modal Approach To Measuring Particulate Iron Speciation In Buoyant Hydrothermal Plumes, Brandy D. Stewart, Jeffry V. Sorensen, Kathleen Wendt, Jason B. Sylvan, Christopher R. German, Karthik Anantharaman, Gregory J. Dick, John A. Breier, Brandy M. Toner

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Processes active within buoyant hydrothermal plumes are expected to modulate the flux of elements, such as Fe, to the deep ocean; however, they are yet to be described in a comprehensive manner through observations or models. In this study, we compare observed particulate Fe (pFe) speciation with thermodynamic (equilibrium) reaction path modeling for three vent fields in the Eastern Lau Spreading Center (ELSC). At each site, particles were collected from the buoyant rising portion of hydrothermal plumes using in situ filtration with a Remotely Operated Vehicle. Filter bound particles were analyzed by synchrotron micro-probe X-ray fluorescence mapping (XRF), X-ray diffraction …


New Amphibian And Reptile Distribution Records From Eastern South Dakota, Usa, Drew R. Davis Jan 2021

New Amphibian And Reptile Distribution Records From Eastern South Dakota, Usa, Drew R. Davis

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Over recent years, the continued collection of voucher specimens has helped to better document the distributions of South Dakota’s amphibians and reptiles. Despite large increases in our knowledge of these distributions, it remains clear that gaps in our understanding remain. Here, I report 17 new county records of six species of amphibians and reptiles from eastern South Dakota (east of the Missouri River) that are the result of fieldwork conducted in September 2020. The majority of these records are from the northern portions of the James River Lowland, Missouri Coteau, and Drift Plains ecoregions (Bryce et al. 1998), which are …


Evaluating The Impacts Of Dam Construction And Longshore Transport Upon Modern Sedimentation Within The Rio Grande Delta (Texas, U.S.A.), Samantha Moore, Elizabeth A. Heise, Marty Grove, Anthony Reisinger, Jude A. Benavides Jan 2021

Evaluating The Impacts Of Dam Construction And Longshore Transport Upon Modern Sedimentation Within The Rio Grande Delta (Texas, U.S.A.), Samantha Moore, Elizabeth A. Heise, Marty Grove, Anthony Reisinger, Jude A. Benavides

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

The modern Rio Grande delta system has experienced a century of dam construction, water removal for irrigation and municipal use, and land use modifications that have dramatically reduced its sediment load. This study examines whether damming has sufficiently limited delivery of upstream sediment to permit locally eroded sources and/or littoral transport along the coast to influence the provenance signal of the Rio Grande delta. Changes in sediment provenance within the Rio Grande’s delta can be detected and quantified by measurement of detrital zircon Uranium–lead dating age distributions. Previous provenance studies indicate that modern Rio Grande river sand upstream of Falcon …


Importance Of Low-Relief Nursery Habitat For Reef Fishes, Michael A. Dance, Ray R. Rooker, Richard J. Kline, Antonietta Quigg, Gregory R. Stunz, R. J. David Wells, Kirsten Lara, Jessica Lee, Bobbie Suarez Jan 2021

Importance Of Low-Relief Nursery Habitat For Reef Fishes, Michael A. Dance, Ray R. Rooker, Richard J. Kline, Antonietta Quigg, Gregory R. Stunz, R. J. David Wells, Kirsten Lara, Jessica Lee, Bobbie Suarez

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Coastal restoration projects to mitigate environmental impacts have increased global demand for sand resources. Unfortunately, these resources are often extracted from sand/shell banks on the inner continental shelf, resulting in significant alteration or loss of low-relief reefs in coastal oceans. Experimental reefs (oyster shell, limestone rubble, composite) were deployed in the western Gulf of Mexico to assess their potential value as nurseries for newly settled reef fishes. Occurrence, abundance, and species richness of juvenile fishes were significantly higher on all three types of low-relief reefs compared with unconsolidated sediment. Moreover, reefs served as nursery habitat for a range of reef …


Enhancing The Seed Germination Process Of Montezuma Cypress (Taxodium Mucronatum Ten.), Alejandro Fierro-Cabo, August Plamann Jan 2021

Enhancing The Seed Germination Process Of Montezuma Cypress (Taxodium Mucronatum Ten.), Alejandro Fierro-Cabo, August Plamann

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Montezuma cypress (Taxodium. mucronatum) is an ecological, cultural and economically valuable riparian tree species. Two experiments evaluating the effectiveness of various seed treatments were conducted to identify germination best practices and to evaluate the dynamics of the germination process. Seeds were collected on two occasions, one year apart, from the only remaining natural T. mucronatum tree stand in the United States. The seeds were subjected to various soaking and stratification conditions. Across all treatments, germinability ranged between approximately 30%-40%, with slightly higher values occurring among the second seed cohort. Overall, no significant differences in germinability were detected in either …