1,721,067 research outputs found
Powering a sustainable future: How environmental review aids Dominion Energy's net-zero mission
No full textIncreasing concentrations of greenhouse gases in the atmosphere, caused by the global reliance on fossil fuels, is one of the leading causes of climate change. As a result, the energy industry is pivoting towards cleaner, more sustainable methods of meeting energy demands. Dominion Energy has employed a multitude of initiatives to combat human-induced climate change, like the process of environmental review. In this paper, I will discuss my experience with the company as an Environmental Services Intern and analyze two environmental reviews. These reviews are comprehensive risk assessments and cautionary responses to potential electric distribution projects that mitigate environmental harm and put protections in place for natural resources. Assessing environmental risk and advising project designers on the necessary permitting needed for their electric distribution projects is a foundational building block of environmental stewardship. Environmental review, while seemingly small, promotes all-around sustainability within the entire company and pushes Dominion Energy farther in reaching their net-zero carbon goals.Geolog
National Fossil Day Event for Colonial National Historical Park (Southeastern Virginia)
No full textOn October 30th, 2021, I ran a Fossil Day outreach event at Colonial National Historical Park (COLO). Preparation for this event included literature surveys, graphic design, and collaboration with the National Park Service (NPS). This culminated in materials and resources for five main stations including a microscope gravel search, a fossil cast-making station, a fossil dig, an arts and crafts station, and a presentation station. On the day of the event, we collected survey responses from 63 people regarding their favorite station, what they learned, what they would improve, and how they heard about this event. Results showed that the fossil dig station was the visitor's favorite station, and that visitors learned a wide range of information from facts about different fossils to facts about how fossils are made. Many of the visitors did not leave a comment on ways to improve, but those that did often indicated that they would like to see a bigger fossil dig experience. Overall, this event was a success, and it was able to educate visitors about some of the core information regarding Virginia’s geologic history.Geolog
Decline in marine invertebrate species richness across the Mid-Pliocene Warm Period in the Virginia Coastal Plain
No full textThe fossil record holds clues that allow scientists to use the past to predict the future and understand how modern ecosystems will respond to anthropogenic climate change. The Mid-Pliocene Warm Period (3.3-3.0 Ma) was an interval of continuous global warming with surface temperatures around 2-3 °C warmer than today. Mid-Pliocene marine invertebrates are well preserved in Yorktown Formation deposits in the Virginia Coastal Plain. Using bulk samples of fossils from before, during, and after the Mid-Pliocene Warm Period, this study developed a dataset of species abundance values and used statistical methods to contribute to the understanding of how climate conditions impact marine invertebrate species richness. Rarefaction analysis results show that species richness declined across the Mid-Pliocene Warm Period. When the Mid-Pliocene Warm Period ended, species richness did not recover to richness levels prior to the temperature increase. Marine invertebrate species abundant during the Mid-Pliocene were able to tolerate warm conditions, while species that are not present during or after Mid-Pliocene warming were not able to tolerate increased temperature conditions. Although marine invertebrates possess strategies to cope with temperature change, the Mid-Pliocene Warm Period was a rapid and geologically short interval (300,000 yrs), and species unable to tolerate warm conditions likely did not survive. These results provide insights into how global warming will impact modern marine invertebrate communities and how large-scale biodiversity patterns could shift.Geolog
Growth rates and sclerochronology of modern Crassostrea virginica from the lower Chesapeake Bay (southeastern Virginia)
No full textPopulations of the Eastern Oyster (Crassostrea virginica) have declined over the last century in the Chesapeake Bay due to anthropogenic factors including climate change and overharvesting. Oyster lifespan is a useful proxy for overall reef health but is difficult to assess without time-consuming and expensive methods, such as sclerochronology. Although morphological proxies for lifespan (i.e., growth-band counting) have been identified in Pleistocene C. virginica, it is unclear whether these same approaches can be applied to modern specimens. This study has three main objectives: (1) quantify maximum lifespan and growth rates in a small sample of modern C. virginica from the Chesapeake Bay, (2) compare growth rates of modern C. virginica to Pleistocene specimens from similar environmental conditions, and (3) assess the validity of growth-band counting as a proxy for estimating lifespan in modern oysters, which would help reduce the cost and time required for certain sclerochronological analyses. Over 1,400 oysters were sampled in 2020 and 2021 from Baines Creek and Felgates Creek, which are tributaries of the Elizabeth and York Rivers, respectively, in southeastern Virginia. The oysters were sampled from a restored, intertidal reef at Baines Creek and a restored, subtidal reef at Felgates Creek, both of which are currently protected from harvesting. The largest ten live oysters from each reef were cleaned, their left valves were bisected at the hinge, and the hinges were embedded in epoxy. The longest three hinges for each of the two sites were processed for sclerochronology. Sample line density varied from 7 to 8 tracks per cm of the hinge, making it possible to collect multiple samples of shell powder per year of original shell growth. The total number of samples collected per hinge varied from 80 to 120. Oxygen and carbon isotope analyses were performed to quantify the number of years each oyster lived and the extent to which growth banding in the hinge corresponds to annual cycles. Preliminary results indicate growth banding in the hinge may not be able to provide an accurate estimate of lifespan. Lifespan was shorter and growth rates were significantly faster for the six modern shells compared to Pleistocene localities, despite similar temperature and salinity of growing conditions.Geolog
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Morphological Variability, Body Size, and Survivorship in Veneroid Bivalves During the Plio-Pleistocene Extinction in Florida
No full textRecent studies of extinction in the fossil record indicate that morphological selectivity can drive evolutionary trends. These investigations have focused primarily on specific morphological traits, and none have directly analyzed the role of morphological variability in promoting survivorship. This study seeks to examine morphological variability, body size, and survivorship in veneroid bivalves during the Plio-Pleistocene extinction in Florida. The Plio-Pleistocene extinction (1.8 Ma) occurred in response to global cooling and changes in ocean circulation possibly related to the emergence of the Isthmus of Panama. Stratigraphic occurrences of veneroid bivalves were compiled from the literature to determine victim and survivor species. Fourteen pairs of species from the same genus or closely related genera were selected for study, each containing one extant species and one species that became extinct during the event. A total of 1429 specimens representing 27 localities were examined from collections at the Florida Museum of Natural History and the Virginia Museum of Natural History. Specimens were sampled from the Pinecrest Beds, the Caloosahatchee Formation, the Jackson Bluff Formation, and the Nashua Formation in Florida. Specimens were identified to the species level and digitally imaged. Landmark coordinate points for morphometric analysis were collected from the hinge, the adductor muscles, the pallial line, and along the shell outline at points representing maximum length and height. Generalized Scaled Procrustes was applied to assess morphological variability and centroid size was calculated to quantify body size. The relationships among morphological variability, body size, and survivorship were assessed using both parametric and non-parametric statistical tests. Results indicate that survivor species have significantly higher morphological variability than victim species. Allometric growth and sampling range do not significantly affect this pattern. A locality-controlled comparison of victims and survivors found no statistically significant differences in morphological variability, possibly indicating that differences in morphological variability are due to ecophenotypic variation. Body size does not appear to significantly affect survivorship in veneroid bivalves. These results suggest that morphological variability may be a significant factor in promoting the survivorship of species.Geolog
Effects of Climate Change On Epibiont Communities in the Neogene of Virginia
No full textAn epibiont is any organism that lives in physical contact with another organism. This study compared two fossil epibiont communities that lived in a tropical and temperate environment. Samples were collected from Chesapecten sp. from the Cobham Bay and Sunken Meadow Members along the James River in eastern Virginia. The top surface of each shell was studied to identify the percent occurrence and average areal extent of total epibionts and individual epibiont species. Rarefaction curves of each community were created to quantify species richness and evenness. Percent occurrence and average areal extent both tended to be higher in the Sunken Meadow Member, which was deposited in a temperate climate. Areal extent of the colonial coral Septastrea marylandica was significantly greater in the Cobham Bay Member. The community in the Cobham Bay Member was more evenly distributed, while the community in the Sunken Meadow had a few very common epibiont taxa and many rare taxa. This study can be used to predict how modern day epibiont communities will react to the current global warming. Future studies can be done to explore how epibiont interactions, such as competition and overgrowth, changed due to climate.Geolog
The Taphonomy, Paleoecology and Depositional Environment of Vertebrate Microfossil Bonebeds from the Late Cretaceous Hell Creek Formation in Garfield County, Montana
No full textVertebrate micro fossil bone beds (VMBs) have been used as a source of paleoecological data for decades, but the processes by which they form are poorly understood. Scatological, lacustrine, and fluvial channel lag processes have all been offered as potential mechanisms by which fossil elements are concentrated. This project tests the recent hypothesis that small lacustrine environments are the first stage in the development of VMBs with fluvial VMBs representing reworked samples of previously deposited lacustrine VMBs. Additionally, this study tested the reliability of reconstructing paleoecology using surface collected bulk samples as opposed to in situ quarrying. Three bulk samples, representing one lacustrine and one fluvial VMB, collected from the Late Cretaceous Hell Creek Formation of Garfield County, Montana were used to compile taxonomic and taphonomic data. In order to reconstruct paleoecology, specimens were identified to the lowest possible taxonomic level. To examine taphonomic features from each site, anatomy, wear, shape, and maximum dimension were measured and/ or noted for each specimen. Rarefaction curves were used to examine taxon richness across the three samples while controlling for sampling size. Detrended correspondence analyses made it possible to compare the three samples according to taxon richness and abundance. The ShannonWiener Diversity Index was calculated as a proxy for taxo evenness across the three VMB samples. Finally, taphonomic data were plotted and statistically analyzed to look for significant differences in size and wear across the fluvial and lacustrine samples. Paleoecological data from this study do not support the hypothesis of a solely lacustrine source for the fluvial VMB. Taphonomic comparisons show fluvial samples had significantly more wear than samples collected from the lacustrine VMB. Rarefaction and detrended correspondence analyses show that surface collected samples may provide a fairly accurate representation of taxon richness measured from the quarried samples, but a poor representation of species composition and abundance.Geolog
Morphological Trends in Venericardia (Bivalvia: Carditidae) of the U.S. Coastal Plain in Relation to Early Cenozoic Global Climate Change
No full textWith global climate shifting at a rapid and unpredictable pace, researchers need additional tools to assess the effects these changes will have on modern organisms. The fossil record can be used to document long-term evolutionary changes in taxa over a variety of ancient climatic events to predict how modern climate change will affect present-day populations. The goal of this study is to quantify trends in size, sha pe, and morphological diversity of the bivalve genus Venericardia from the U.S. Atlantic Coastal Plain in response to global temperature changes over the early Cenozoic. Paleocene, Oligocene, and Miocene specimens were obtained from museum collections, identified to the species level, and photographed in both interior and crosssectional views. The resulting photos were used to collect landmark coordinates, which were the raw data used to quantify mor phology. Landmark data from Eocene specimens were com piled from previous studies, for a total of 848 interior specimens, 541 crosssectional specimens, and 32 species. Body size trends were quantified over time by calculating an average centroid size for each venericard species and subsequently plotting average centroid sizes over time based on species' stratigraphic ranges. To describe shape changes over time, the landmark coordinates were transformed into Procrustes coordinates to remove any variation due to rotation, translation, or size. Principal components analysis was then used to define principal com ponents and create a morphospace, which facilitated comparisons of temporal differences in shell shape. To quantify morphological diversity over time, multivariate variance was calculated using the principal components from the P C A. All three mor phological variables were correlated to global temperature to see if statistically significant relationships existed. Venericard body size is positively correlated with temperature, although a time lag exists between size changes and temperature changes. Venericard shape is also significantly correlated with temperature. Body size and shape do not change significantly over the Paleocene-Eocene Thermal Maximum, but venericards become smaller and more globose in shape with more compact hinges and wider-set adductor muscles after the Eocene-Oligocene cooling. Morphological diversity does not show a strong relationship to temperature, but is more likely related to taxonomic diversity.Geolog
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