Search

As a result of the 2019 coronavirus disease pandemic, many universities were required to make quick decisions to accommodate social-distancing guidelines. Cherished university events such as commencement and spring convocations were postponed or canceled. Such decisions were made in an effort to curb the number of people infected with the virus. Institutions were also forced to consider how to continue educating students in the midst of a pandemic. In many instances, faculty were required to transition their face-to-face courses to an online format. Some instructors were familiar with the instructional strategies and technological tools needed for effective online teaching, whereas other, novice faculty were hesitant or even resistant to the idea of online teaching and learning. This case study at a Midwestern master's level university examines the perceptions of faculty (N = 183) regarding the quick transition of their courses to an online medium during the spring 2020 semester. We administered a web-based survey instrument consisting of two sections. Section I had 20 demographic questions and Section II had 28 statements rated on a 7-point Likert-type scale ranging from 1 ("strongly disagree") to 7 ("strongly agree"). Section II assessed perceptions and attitudes about the quick transition to online, perceptions of students' engagement in the courses before and after the transition, and professors' level of satisfaction with the transition. The data were analyzed using frequency, mean, and analysis of covariance. Findings reveal that generally faculty felt that course quality remained the same, that students' engagement and performance declined during the pandemic, and that satisfaction levels with the transition were low.

Marine animal forests (MAFs) are benthic ecosystems characterised by biogenic three‐dimensional structures formed by suspension feeders such as corals, gorgonians, sponges and bivalves. They comprise highly diversified communities among the most productive in the world's oceans. However, MAFs are in decline due to global and local stressors that threaten the survival and growth of their foundational species and associated biodiversity. Innovative and scalable interventions are needed to address the degradation of MAFs and increase their resilience under global change. Surprisingly, few studies have considered trophic interactions and heterotrophic feeding of MAF suspension feeders as an integral component of MAF conservation. Yet, trophic interactions are important for nutrient cycling, energy flow within the food web, biodiversity, carbon sequestration, and MAF stability. This comprehensive review describes trophic interactions at all levels of ecological organisation in tropical, temperate, and cold‐water MAFs. It examines the strengths and weaknesses of available tools for estimating the heterotrophic capacities of the foundational species in MAFs. It then discusses the threats that climate change poses to heterotrophic processes. Finally, it presents strategies for improving trophic interactions and heterotrophy, which can help to maintain the health and resilience of MAFs. [ABSTRACT FROM AUTHOR]

Large quantities of anthropogenic nitrogen (N) in the marine environment are detrimental for coastal ecosystems and understanding the magnitude and distribution of this N opens paths to remediation. One area of concern is Cocos Lagoon, in the south of Guam, Northern Mariana Islands, which hosts a diversity of corals including Acropora species listed in the Endangered Species Act. Degradation of Guam's coral reefs may be influenced by untreated sewage effluent. To gain insight into the spatial extent of human N pollution, we deployed 50 macroalgal thalli (Padina sp.) as bio-indicators in a grid pattern over the entire lagoon for one week and then measured the stable N isotopes of bio-available N ([delta][sup.15]N). We observed relatively low [delta][sup.15]N values (~1-2[per thousand]) in the shallow areas in the east suggesting coastal currents bringing in fixed N from the open ocean or local [N.sub.2] fixation. The comparatively high [delta][sup.15]N values (~6 [per thousand]) in the deeper channel of the lagoon suggest sewage as a major source of N. The distribution of [delta][sup.15]N values was not determined by the distance to N sources, such as river outlets or the tourist resort on Cocos Island but by the bathymetry, which affects the residence time and influx of oceanic water. Keywords: N stable isotopes, algal bioassays, tropical lagoon, Padina sp., The increasing impact of human activities on the nitrogen (N) cycle is manifested at various temporal (long vs. short term) and spatial (global vs. local) scales. Fossil fuel combustion, the [...]

Both human populations and marine biodiversity are concentrated along coastlines, with growing conservation interest in how these ecosystems can survive intense anthropogenic impacts. Tropical urban centres provide valuable research opportunities because these megacities are often adjacent to mega‐diverse coral reef systems. The Pearl River Delta is a prime exemplar, as it encompasses one of the most densely populated and impacted regions in the world and is located just northwest of the Coral Triangle. However, the spatial and taxonomic complexity of this biodiversity, most of which is small, cryptic in habitat and poorly known, make comparative analyses challenging. We deployed standardized settlement structures at seven sites differing in the intensity of human impacts and used COI metabarcoding to characterize benthic biodiversity, with a focus on metazoans. We found a total of 7184 OTUs, with an average of 665 OTUs per sampling unit; these numbers exceed those observed in many previous studies using comparable methods, despite the location of our study in an urbanized environment. Beta diversity was also high, with 52% of the OTUs found at just one site. As expected, we found that the sites close to point sources of pollution had substantially lower diversity (44% less) relative to sites bathed in less polluted oceanic waters. However, the polluted sites contributed substantially to the total animal diversity of the region, with 25% of all OTUs occurring only within polluted sites. Further analysis of Arthropoda, Annelida and Mollusca showed that phylogenetic clustering within a site was common, suggesting that environmental filtering reduced biodiversity to a subset of lineages present within the region, a pattern that was most pronounced in polluted sites and for the Arthropoda. The water quality gradients surrounding the PRD highlight the unique role of in situ studies for understanding the impacts of complex urbanization pressures on biodiversity. [ABSTRACT FROM AUTHOR]

The swift transition to remote learning in response to the COVID‐19 pandemic presented substantial challenges for faculty at many universities. This study explores faculty perceptions that influenced their satisfaction with the transition to online classes as a result of the COVID-19 pandemic. Challenges relating to teaching online classes and the supportive environment provided by the institution had the strongest effects. Other important factors were comfort with online teaching and perceived quality of interactions with students. Teaching experience, tenure status, and other demographic variables had no significant effect on satisfaction with transition to online teaching. Application of lessons learned to future emergencies as well as online and blended classes are discussed. [ABSTRACT FROM AUTHOR]

Layers of ice and dust (i.e., "mantle") are found throughout the mid‐latitudes of Mars, where they drape and mute topography and record the recent climate history. Many of the youngest Late Amazonian "latitude‐dependent mantles" have been characterized, but the full range of mantle characteristics, including variations in ice content and age, has not been well documented. To advance our understanding of these ice‐dust units, we use SHAllow RADar (SHARAD) radar sounding data to constrain the subsurface physical properties of a widespread Middle Amazonian mantle unit within Deuteronilus Mensae. This region hosts a high density of glacial landforms, which allows assessment of the stratigraphic relationship between mantle deposits and glacial ice. SHARAD reflectors at the base of the mantle units are used to determine moderate dielectric constants (∼5.75) and high loss tangents (∼0.038). These radar properties imply relatively limited ice content and high‐loss mantling materials with possible enhanced roughness or subsurface scattering. Further, we interpret deeper reflectors that are continuous with glacier basal reflectors and that suggest materials with lower dielectric constants (∼3.2–4.5) and loss tangents (0.0071–0.0120) to be due to extensions of stagnant, possibly lithic‐rich, glacier ice that are buried by a mantle layer. This study demonstrates the high variability in the origins and evolution of mid‐latitude mantling units on Mars. While the most recent latitude‐dependent mantling deposits may still be ice‐rich, older deposits, such as those preserved in Deuteronilus Mensae and elsewhere in the mid‐latitudes of Mars, may be largely desiccated or contain a more heterogeneous and limited distribution of ice. Plain Language Summary: Layers of ice and dust (called "mantle") on Mars are widespread in the middle latitudes. These layers are found to thickly blanket topography and were formed from changes in Mars' climate within the past million to hundreds of millions of years. However, unknown are the complete range of ice content and ages of the mantle layers. To better characterize their properties and relationships with glaciers in the region, we use radar data from the SHAllow RADar instrument, which allows for identification and delineation of the depth and thickness of layers beneath the surface in addition to their material properties. We find that mantle layers have radar characteristics more consistent with low ice content and properties that greatly reduce the strength of the radar signal. Further, we find radar evidence consistent with mantle layers burying the ends of glacial ice. This study demonstrates that mantle layers on Mars have a wide range of ice contents and ages, with some being less ice rich than their surface characteristics alone might imply. Key Points: The subsurface properties of ice‐dust (mantle) layers are characterized with SHAllow RADar radar data in a glaciated mid‐latitude region of MarsMantle layers have moderate dielectric constants and high radar attenuation, indicating lower possible ice content than other mantle unitsRadar properties and surface geomorphology are consistent with mantle burying the termini of glaciers, obscuring boundaries [ABSTRACT FROM AUTHOR]

Fish have one of the highest occurrences of individual specialization in trophic strategies among Eukaryotes. Yet, few studies characterize this variation during trophic niche analysis, limiting our understanding of aquatic food web dynamics. Stable isotope analysis (SIA) with advanced Bayesian statistics is one way to incorporate this individual trophic variation when quantifying niche size. However, studies using SIA to investigate trophodynamics have mostly focused on species‐ or guild‐level (i.e., assumed similar trophic strategy) analyses in settings where source isotopes are well‐resolved. These parameters are uncommon in an ecological context. Here, we use Stable Isotope Bayesian Ellipses in R (SIBER) to investigate cross‐guild trophodynamics of 11 reef fish species within an oceanic atoll. We compared two‐ (δ15N and δ13C) versus three‐dimensional (δ15N, δ13C, and δ34S) reconstructions of isotopic niche space for interpreting guild‐, species‐, and individual‐level trophic strategies. Reef fish isotope compositions varied significantly among, but also within, guilds. Individuals of the same species did not cluster together based on their isotope values, suggesting within‐species specializations. Furthermore, while two‐dimensional isotopic niches helped differentiate reef fish resource use, niche overlap among species was exceptionally high. The addition of δ34S and the generation of three‐dimensional isotopic niches were needed to further characterize their isotopic niches and better evaluate potential trophic strategies. These data suggest that δ34S may reveal fluctuations in resource availability, which are not detectable using only δ15N and δ13C. We recommend that researchers include δ34S in future aquatic food web studies. [ABSTRACT FROM AUTHOR]