Life and death in the Chicxulub impact crater: a record of the Paleocene–Eocene Thermal Maximum

Thermal stress on the biosphere during the extreme warmth of the Paleocene–Eocene Thermal Maximum (PETM) was most severe at low latitudes, with sea surface temperatures at some localities exceeding the 35 C at which marine organisms experience heat stress. Relatively few equivalent terrestrial sections have been identified, and the response of land plants to this extreme heat is still poorly understood. Here, we present a new record of the PETM from the peak ring of the Chicxulub impact crater that has been identified based on nannofossil biostratigraphy, an acme of the dinoflagellate genus Apectodinium, and a negative carbon isotope excursion. Geochemical and microfossil proxies show that the PETM is marked by elevated TEXH 86-based sea surface temperatures (SSTs) averaging 37:8 C, an increase in terrestrial input and surface productivity, salinity stratification, and bottom water anoxia, with biomarkers for green and purple sulfur bacteria indicative of photic zone euxinia in the early part of the event. Pollen and plants spores in this core provide the first PETM floral assemblage described from Mexico, Central America, and the northern Caribbean. The source area was a diverse coastal shrubby tropical forest with a remarkably high abundance of fungal spores, indicating humid conditions. Thus, while seafloor anoxia devastated the benthic marine biota and dinoflagellate assemblages were heat-stressed, the terrestrial plant ecosystem thrived

Insights into past land-use and vegetation change in the Llanos de Moxos (Bolivia) using fungal non-pollen palynomorphs

Here we document a 1000-year fungal record from the raised-field region of the Llanos de Moxos, a seasonally inundated forest-savanna mosaic in the Bolivian Amazon. Fungi are extremely sensitive to changes in vegetation due to their close relationship with the local environment, providing a useful proxy for past local vegetation and land-use change. Here the remains of fungal non-pollen palynomorphs (NPPs) are identified from a sediment core taken from Laguna El Cerrito. A multivariate constrained ordination is used to extract relationships between the fungal NPP types and environmental gradients, specifically, tree cover, near-shore vegetation, crop cultivation, burning and local sediment input. NPP types such as Neurospora cf. cerealis are identified as indicative of pre- European agriculture and offer the ability to expand on the temporal range of cultivation in the raised-field region. Constrained cluster analysis indicates that the most significant changes in the NPP assemblage occurs c. 1500 and c. 1700 CE, corresponding to the arrival of Europeans to the Americas and Jesuit missionaries to the Llanos de Moxos respectively. The modern savanna landscape is one shaped by changes in land-use and the introduction of cattle following the European Encounter

The Midway to Carrizo Succession in the Southeastern Texas Gulf Coast: evolution of a tidally-influenced coastline

This study demonstrates that the Upper Midway to Carrizo stratigraphic succession in southeastern Texas contains a greater variability in depositional systems, facies, and reservoir sandstone-body geometry than previously documented. It also documents significant tidal processes on sedimentation in the Wilcox Group and Carrizo Formation

First Record of Fungal Diversity in the Tropical and Warm-Temperate Middle Miocene Climate Optimum Forests of Eurasia

The middle Miocene Climate Optimum (MMCO) was the warmest interval of the last 23 million years and is one of the best analogs for proposed future climate change scenarios. Fungi play a key role in the terrestrial carbon cycle as dominant decomposers of plant debris, and through their interactions with plants and other organisms as symbionts, parasites, and endobionts. Thus, their study in the fossil record, especially during the MMCO, is essential to better understand biodiversity changes and terrestrial carbon cycle dynamics in past analogous environments, as well as to model future ecological and climatic scenarios. The fossil record also offers a unique long-term, large-scale dataset to evaluate fungal assemblage dynamics across long temporal and spatial scales, providing a better understanding of how ecological factors influenced assemblage development through time. In this study, we assessed the fungal diversity and community composition recorded in two geological sections from the middle Miocene from the coal mines of Thailand and Slovakia. We used presence-absence data to quantify the fungal diversity of each locality. Spores and other fungal remains were identified to modern taxa whenever possible; laboratory codes and fossil names were used when this correlation was not possible. This study represents the first of its kind for Thailand, and it expands existing work from Slovakia. Our results indicate a total of 281 morphotaxa. This work will allow us to use modern ecological data to make inferences about ecosystem characteristics and community dynamics for the studied regions. It opens new horizons for the study of past fungal diversity based on modern fungal ecological analyses. It also sheds light on how global variations in fungal species richness and community composition were affected by different climatic conditions and under rapid increases of temperature in the past to make inferences for the near climatic future

PALEOGENE MIRELANDS OF THE UPPER MISSISSIPPI EMBAYMENT, WESTERN KENTUCKY

Detailed petrography, geochemistry, and palynology together describe the depositional environments and paleoecology of an abandoned meander-fill system in western Kentucky. Oriented block petrography reveals alternating clay-rich and attrinite-rich zones of variable thickness. Woody tissues, where present, do not show dessication features and deflation layers could not be identified. Overall, petrography is indicative of a topogenous mire. Mire palyno-assemblages are less diverse than assemblages reported from clays in the region. Castanea-Cupuliferoidaepollenites assemblages dominate the entire system and other tree pollen are common; fungal spores are relatively uncommon. Weighted statistical analyses reveal ecological groupings beyond this dominance and define botanical succession within the mire. The nearestliving- relative method for determining paleoclimate indicates temperate to warm temperate conditions during deposition. Palynology indicates a Claibornian stage, middle Eocene age for the deposit

An alternative to acetolysis: application of an enzyme-based method for the palynological preparation of fresh pollen, honey samples and bee capsules

Acetolysis has been widely used for the preparation of modern pollen samples since its introduction by Erdtman. It has several disadvantages in both safety and resultant changes to the size and, in some cases, structure of pollen grains. The enzymatic technique introduced by Schols and colleagues is tested on a fresh pollen sample, a honey sample and a bee pollen capsule. The technique increases processing time, but is completely non-toxic, easy to complete and comparable in cost to acetolysis. Even very fragile grains are not damaged by this technique

KYHTL at OPaL: Developing Skills in Melissopalynology in Support of Regional Beekeepers

The Kentucky Honey Testing Laboratory (KYHTL) is a new venture at Bluegrass Community and Technical College that helps honey producers assure the quality of their product and provide certification required for compliance with truth-in labeling guidelines. KYHTL is the first project to utilize melissopalynology in support of DNA metabarcoding to identify pollen in honey samples. This endeavor aims to bring the US closer to Jones and Bryant’s (1980) goal of having a data base of the compositional properties of honey in our 50 states and eventually for individual regions.https://scholarworks.moreheadstate.edu/celebration_posters_2022/1039/thumbnail.jp

Introduction to Paleontology Research through the Boudreaux Bend Project

https://scholarworks.moreheadstate.edu/student_scholarship_posters/1058/thumbnail.jp

Petrology, Palynology, and Geochemistry of Gray Hawk Coal (Early Pennsylvanian, Langsettian) in Eastern Kentucky, USA

This study presents recently collected data examining the organic petrology, palynology, mineralogy and geochemistry of the Gray Hawk coal bed. From the Early Pennsylvanian, Langsettian substage, Gray Hawk coal has been mined near the western edge of the eastern Kentucky portion of the Central Appalachian coalfield. While the coal is thin, rarely more than 0.5-m thick, it has a low-ash yield and a low-S content, making it an important local resource. The Gray Hawk coal palynology is dominated by Lycospora spp., and contains a diverse spectrum of small lycopods, tree ferns, small ferns, calamites, and gymnosperms. The maceral assemblages show an abundance of collotelinite, telinite, vitrodetrinite, fusinite, and semifusinite. Fecal pellet-derived macrinite, albeit with more compaction than is typically seen in younger coals, was observed in the Gray Hawk coal. The minerals in the coal are dominated by clay minerals (e.g., kaolinite, mixed-layer illite/smectite, illite), and to a lesser extent, pyrite, quartz, and iron III hydroxyl-sulfate, along with traces of chlorite, and in some cases, jarosite, szomolnokite, anatase, and calcite. The clay minerals are of authigenic and detrital origins. The occurrence of anatase as cell-fillings also indicates an authigenic origin. With the exception of Ge and As, which are slightly enriched in the coals, the concentrations of other trace elements are either close to or much lower than the averages for world hard coals. Arsenic and Hg are also enriched in the top bench of the coal and probably occur in pyrite. The elemental associations (e.g., Al2O3/TiO2, Cr/Th-Sc/Th) indicate a sediment-source region with intermediate and felsic compositions. Rare metals, including Ga, rare earth elements and Ge, are highly enriched in the coal ashes, and the Gray Hawk coals have a great potential for industrial use of these metals. The rare earth elements in the samples are weakly fractionated or are characterized by heavy-REE enrichment, indicating an input of natural waters or probably epithermal solutions

Fungi in a Warmer World: Middle Miocene Fungal Assemblages and Diversity from Alum Bluff, Florida

Fungi play a key role in the terrestrial carbon cycle, soil formation, and overall plant growth as terrestrial decomposers (1, 2). Thus, the study of fungi, especially in the fossil record, is critical to understanding how fungal assemblages will react to future warming events. Fossil fungi provide a large-scale, long-term dataset unavailable from modern records, allowing for the generation of viable paleoclimate reconstructions and predictions (3, 4). Despite their importance and advantages in forming ecological and climatological interpretations, deep-time fungi have been underutilized (3). The Fungi in a Warmer World (FiaWW) project aims to deliver the first global view of fungal biodiversity, ecology, and biogeography for the Miocene Climate Optimum (MCO): the warmest interval of the last 23 MY. The MCO is a good proxy for near-future climate change scenarios because atmospheric CO2 concentrations ranged between current concentrations of ~400ppm and future projected concentrations for the end of this century (5, 6).https://scholarworks.moreheadstate.edu/celebration_posters_2022/1040/thumbnail.jp