Gulf Coast Research Articles

Regional Sediment Management in US Coastal States: Historical Trends and Future Predictions

Sea level rise and natural disasters, such as hurricanes and tropical storms, are resulting in coastal erosion-related problems across the US. Beach nourishment is one of the most commonly adopted solutions for erosion mitigation. Borrow sources for nourishment are often from offshore or upland mines. However, in some areas, sediment availability from known borrow sources is becoming scarce. This suggests that sediment should be considered a non-renewable resource within the framework of long-term planning and coastal management decisions. Regional Sediment Management (RSM), or the beneficial use of dredge material (BUDM), targets inlets for borrowing material and can also be a more cost-efficient strategy that has widely been supported by the US Army Corps of Engineers as a system-based approach. However, not all states have embraced this approach, and a national-scale evaluation of these projects in coastal management and adaptation is needed. This study examines past RSM/BUDM projects in the top ten most highly nourished states in the US and compares those trends to a selection of minimally nourished states from different coasts. Based on the historical trends identified, the volume of sediment required for future RSM/BUDM projects in these areas over the next 50 years is predicted using Auto Regressive Integrated Moving Average (ARIMA) models. Although growth in the total number of RSM/BUDM projects was measured over time, there was a decline in the volume of sediment placed for these projects. Results of the forecasting model suggest that CA, NC, and the FL Gulf Coast could require the highest volume of sediments for RSM/BUDM activities over the next 50 years. Based solely on proximity to inlets for sediment resources, DE, FL Atlantic, and NJ coasts are potential beaches that can increase BUDM activities. This study aims to provide a framework to evaluate the suitability of future RSM/BUDM projects in efforts to mitigate coastal erosion.

C-HAND: near real-time coastal flood mapping

The Texas Gulf Coast region contains significant centers of population, infrastructure, and economy and is threatened by intensifying tropical storms. The flooding from these tropical storms often has multiple compounding drivers. This characteristic presents a complex numerical problem where a simulation must consider multiple hydrologic forcings. While several procedures exist for addressing this problem numerically, they tend to be resource-intensive and cannot be conducted in near real-time. We extend GeoFlood, a reduced physics approach for fluvial flood forecasting, to rapidly predict coastal and compound fluvial-coastal inundation. This method is validated against a numerical ocean circulation model (ADCIRC) simulation of Hurricane Ike, a major coastal flooding event that happened on the Texas Gulf Coast in 2008. We show that the inundation map generated by coastal HAND (c-HAND) has reasonable agreement with the ADCIRC simulation while taking about 1.7% of the time currently needed to run ADCIRC on a supercomputer. While our model correctly predicts 99% of ADCIRC-inundated DEM cells, it also overpredicts inundated area by a factor of approximately 27%. We combine c-HAND with the GeoFlood framework for fluvial flood forecasting to create a compound fluvial-coastal inundation mapping workflow that can be run in near real-time. c-HAND's fast wall-clock time and low CPU requirements can support decision making by first response personnel. The method provides timely and convenient access to crucial information, such as the locations of flooded roads and inundated coastal areas.

Spatio-Temporal Pattern and Vulnerability Assessment of the Human Settlements along the Beibu Gulf Coast of Guangxi, China

Human settlement development is intricately linked to production and life, and development quality is a partial indicator of the local community’s social, economic, cultural, and environmental progress. Furthermore, the human settlements’ vulnerability affects their sustainable development potential. Due to the “One Belt, One Road” initiative and land and sea corridor development in southwestern China, the Beibu Gulf coast in Guangxi is the sole waterway bridgehead used by China for opening trade with ASEAN. By examining the region’s human settlements and its potential for sustainable development, we established a benchmark for the region’s seaward economy and human settlements to achieve synergistic progress, as well as to enhance regional integration. Based on the systematic evaluation of the quality of human settlements along the Beibu Gulf coast in Guangxi, the vulnerability assessment model of human settlement was adopted to analyse the vulnerability and spatial–temporal patterns of nearby human settlements in 2010–2019, while the multiple linear regression model was used to explore their influencing factors. Our findings indicate that the quality of human settlements in the study area has experienced three distinct stages. In the early stage (2010–2012), we noted an overall year-on-year increase in settlement quality. However, in the middle stage (2013–2016), Fangchenggang and Beihai experienced a decline followed by an increase, while Qinzhou demonstrated a steady growth in settlement quality. Qinzhou continued to experience growth, albeit at a slower rate, while Fangchenggang’s rate of increase surpassed that of Beihai. The human settlements’ high-quality centre shifted between Qinzhou and Fangchenggang in the late stage (2017–2019). Additionally, in recent years, the settlements’ high-quality centre has shifted towards the western part of the region. The habitat’s sensitivity has grown slowly, as has the responsiveness index, but the vulnerability index continues to decline, and it is characterised by a spatial differentiation ranging from low to high values in a centre–east–west direction. The region’s human settlement quality is primarily influenced by economic development. The region’s habitat vulnerability is primarily caused by responsibility, and the primary factors affecting responsibility are regional imbalances in social service development, the population’s welfare, and employment and infrastructure.

Precision in mapping and assessing mangrove Biomass: Insights from the Persian Gulf coasts

This groundbreaking research makes a contribution to climate change adaptation studies by filling a crucial knowledge gap related to the precise evaluation of mangrove biomass—an essential element influencing the future trends of coastal ecosystems. Specifically, the study concentrates on the Hara Biosphere Reserve (HBR) on the coasts of the Persian Gulf (PG), aiming to generate precise maps of mangrove biomass. The methodological approach involves a comprehensive analysis, including the utilization of Landsat imagery to establish an NDVI map of mangroves, the application of the Cumulative Sum (CUSUM) method to determine a threshold NDVI value for distinguishing between tall and dwarf mangroves, and the subsequent mapping of their distribution in both coastal and island zones. Additionally, the study calculates above-ground biomass (AGB) and below-ground biomass (BGB) values in sample plots, develops a regression relationship between biomass and NDVI values, and integrates maps of tall and dwarf mangrove extent with spatial variations in AGB and BGB. Noteworthy outcomes include the identification of a threshold NDVI value (0.63) for distinguishing mangrove types and revealing distinct biomass values for mangroves in both coastal and island zones. Significantly, tall mangroves positioned on the seaward edges exhibit higher biomass in both zones than dwarf mangroves. These findings shed light on the potential exacerbation of climate change impacts, such as rising sea levels and changing tidal range on mangroves of the coasts of the PG due to the heightened productivity and specific spatial distribution of tall mangroves. Recognizing these structural characteristics and production disparities is crucial for developing effective climate change adaptation programs. Integrating such insights into management strategies is emphasized as pivotal for enhancing the efficiency and success of these programs, presenting a robust solution for protecting mangroves in diverse coastal areas.

Parvodontia relampaga sp. nov.: A Cystostereaceae fungal pathogen that is the causal agent of relampago blight of woody plants in Florida, USA

Starting in the fall of 2019, mortality, blight symptoms, and signs of white fungal mycelia were observed on external host tissues of non-native landscape trees as well as numerous native trees, understory shrubs, and vines throughout northern and central Florida, USA. We determined that the fungus is an undescribed species of Basidiomycota based on morphological characteristics and DNA sequence analysis. Phylogenetic analyses of the internal transcribed spacer (ITS), large subunit (LSU), and translation elongation factor 1-alpha (tef1) regions revealed that this novel plant pathogen is an undescribed taxon of the genus Parvodontia (Cystostereaceae, Agaricales). We propose the name Parvodontia relampaga sp. nov. which describes its unique morphological features and phylogenetic placement. We confirmed the pathogenicity of P. relampaga in greenhouse inoculations on host plants from which strains of this novel pathogen were isolated, including the non-native gymnosperm Afrocarpus falcatus, the non-native and commercially important Ligustrum japonicum, and the native tree Quercus hemisphaerica. P. relampaga was also detected on a total of 27 different species of woody host plants, including such economically and ecologically important hosts as Fraxinus, Ilex, Magnolia, Persea, Prunus, Salix, Vitis, and Vaccinium. For this new plant disease, we propose the name “relampago blight,” which refers to the lightning-like rhizomorph growth (relámpago means ‘lightning’ in Spanish). This study presents a newly discovered fungal taxon with a wide host range on both angiosperms and gymnosperms that may be an emerging pathogen of concern in Florida and the Gulf Coast region.

Comparative Osteology Study of Ariid Catfishes along the Coast of Gulf of Mannar and Wadge Bank, Tamil Nadu

Background: Taxonomic ambiguity still exists in ariid catfish species identification. Morphological similarities occur in ariid catfishes which lead to misidentification of the species. To overcome this taxonomic ambiguity osteology is one of the effective integrated taxonomic tools for species discrimination. From this study, we provide an osteotaxonomic key for the field identification of ariid catfish species. Methods: The fish samples were cleaned and washed with the freshwater put into the sample for 1% potassium hydroxide solution (KOH). Then fish samples were allowed for alkali digestion of muscle in the solution for 24-48 hours depending on the condition of the specimen. After the completion of the muscle digestion process, Alizarin S dye was used for staining the fish bones. Result: The present paper deals with a comparative study of the five Ariidae family species discussed, they are Arius arius (Hamilton,1822), Plicofollis layardi (Gunther,1866), Netuma thalassina (Ruppell, 1837), Nemapteryx caelata (Valenciennes, 1840) and Osteogeneiosus militaris (Linnaeus, 1758). The osteological portions used for this study like premaxillary, dentary, neurocranium, otolith, vertebral and caudal bone. The aforementioned osteological portions made the important primitive characters that will be used to differentiate the species.

Labile organic matter promotes nitrogen retention in natural and constructed gulf coast marshes

Coastal marshes mitigate allochthonous nitrogen (N) inputs to adjacent marine habitat; however, their extent is declining rapidly. As a result, marsh restoration and construction have become a major foci of wetland management. Constructed marshes can quickly reach similar plant biomass to natural marshes, but biogeochemical functions like N removal and retention can take decades to reach functional equivalency, often due to lags in organic matter (OM) pools development in newly constructed marshes. We compared denitrification and dissimilatory nitrate reduction to ammonium (DNRA) rates in a 32 year-old constructed marsh and adjacent reference marsh in the Northern Gulf of Mexico. Marsh sediments packed into 3 mm “thin discs” were subjected to three OM quality treatments (no OM addition, labile OM, or recalcitrant OM) and two N treatments (ambient nitrate or elevated nitrate) during a 13 day incubation. We found that OM addition, rather than marsh type or nitrate treatment, was the most important driver of nitrate reduction, increasing both denitrification and DNRA and promoting DNRA over denitrification in both marshes. Fungal and bacterial biomass were higher in the natural marsh across treatments, but recalcitrant OM increased fungal biomass in the constructed marsh, suggesting OM-limitation of fungal growth. We found that constructed marshes are capable of similar denitrification and DNRA as natural marshes after 30 years, and that labile OM addition promotes N retention in both natural and constructed marshes.Graphical Conceptual figure highlighting the findings of this experiment. Under control treatment with no C addition (bottom panel), constructed and natural marshes have similar rates of both DNRA and denitrification. The natural marsh has higher fungal and bacterial biomass, while fungal biomass is not detectable in the constructed marsh. Under labile OM additions (upper left panel), rates of both DNRA and denitrification are increased and DNRA becomes favored over denitrification in both marshes. Recalcitrant OM additions (upper right) increase denitrification, but do not affect DNRA or % denitrification. The addition of recalcitrant OM also increases the detectability of fungal biomass in the constructed marsh.

Catastrophic storms, forest disturbance, and the natural history of Swainson's warbler.

The core breeding range of Swainson's warbler (Limnothlypis swainsonii) overlaps a zone of exceptionally high tornado frequency in southeastern North America. The importance of tornadoes in creating breeding habitat for this globally rare warbler and other disturbance-dependent species has been largely overlooked. This paper estimates tornado frequency (1950-2021) and forest disturbance in the 240 counties and parishes in which breeding was documented from 1988 to 2014. The frequency of destructive tornadoes (EF1-EF5) varied 6-fold across the breeding range with a peak in the Gulf Coast states. Counties from east Texas to Alabama experienced the lowest median return interval of 5.4 years per 1000 km2, resulting in approximately 2477 ha of forest damage per 1000 km2 per century, based on current forestland cover. Tornadoes were significantly less frequent north and east of the core breeding range, with return intervals increasing to 9.1 years per 1000 km2 for breeding counties on the Atlantic coastal plain, 10.2 years per 1000 km2 in the Ozark Mountains, and 32.3 years per 1000 km2 in the Appalachian Mountains. Breeding counties within 150 km of the coastline from east Texas to North Carolina are also subjected to the highest frequency of hurricanes in the Western Hemisphere. Hurricanes often cause massive forest damage but archived meteorological and forestry data are insufficient to estimate the aggregate extent of forest disturbance in breeding counties. Nevertheless, the combined impact of tornadoes and hurricanes in the pre-Anthropogenic era was likely sufficient to produce a dynamic mosaic of early-successional forest crucial for the breeding ecology of Swainson's warbler. To ensure the long-term survival of this rare warbler, it is advisable to develop habitat management plans that incorporate remote sensing data on early-successional forest generated by catastrophic storms as well as anthropogenic activities.

Increasing the resilience of the Texas power grid against extreme storms by hardening critical lines

AbstractThe Texas power grid on the Gulf Coast of the United States is frequently hit by tropical cyclones (TCs) causing widespread power outages, a risk that is expected to substantially increase under global warming. Here we introduce a new approach that combines a probabilistic line failure model with a network model of the Texas grid to simulate the spatio-temporal co-evolution of wind-induced failures of high-voltage transmission lines and the resulting cascading power outages from seven major historical TCs. The approach allows reproducing observed supply failures. In addition, compared to existing static approaches, it provides a notable advantage in identifying critical lines whose failure can trigger large supply shortages. We show that hardening only 1% of total lines can reduce the likelihood of the most destructive type of outage by a factor of between 5 and 20. The proposed modelling approach could represent a so far missing tool for identifying effective options to strengthen power grids against future TC strikes, even under limited knowledge.

Hurricane season hindsight 2020: Applying the IDEA model toward local tropical cyclone forecasts.

Hurricane Laura began as a disorganized tropical depression in August 2020. Early forecast guidance showed that the tropical cyclone could either completely dissipate or strengthen to a major hurricane as it approached the United States Gulf Coast. While this uncertainty was known by meteorologists, it was not necessarily communicated to the public in a direct manner. As it turned out, the worst-case scenario was the correct one. The tropical depression rapidly intensified and made landfall near Cameron, Louisiana, with sustained winds of 150 mph, making Laura a Category 4 hurricane on the Saffir-Simpson scale. Laura's rapid intensification caught some people off guard. Ideally, weather forecasts would have begun warning Louisiana residents to prepare for the possibility of a devastating hurricane in the early stages of tropical cyclone development. No one is suggesting that meteorologists did anything wrong. However, with the benefit of hindsight and decades of scholarly research in risk communication, we can speculate how an ideal forecast would have been written. This paper demonstrates that there are some simple considerations that could be made that might better alert the public to future hurricane worst-case scenarios, even in uncertain situations.

Nitrogen application during rhizoma peanut shoot emergence affects planting‐year nitrogen fixation

AbstractRhizoma peanut (Arachis glabrata Benth.; RP) is an important perennial forage legume in the US Gulf Coast region, but it is vegetatively propagated from rhizomes and relatively slow to establish. There are reports that N fertilization enhances RP establishment, but other evidence suggests plant N content and establishment rate may not benefit. Understanding the effect of N fertilizer on RP biological N2 fixation will help elucidate this response. Our objective was to determine the effect of RP genotype and N fertilization during shoot emergence on N2 fixation and N accumulation during the year of planting. Replicated field experiments were conducted in adjoining fields; one was planted in 2016 and the other in 2017. Treatments were the factorial combinations of two RP entries (decumbent germplasm Ecoturf and upright cultivar ‘UF Tito’) and three N rates (0, 40, and 80 kg N ha−1 applied 10 wk after planting; 1% of total N as 15N) arranged in a randomized complete block design with four replications. Across N rates, upright cultivar UF Tito generally had greater N concentration and content in aboveground and belowground plant parts compared with decumbent germplasm Ecoturf. Nitrogen fertilization generally reduced the percentage of N derived from atmosphere and the amount of fixed N (BNF) during the year of planting, but it did not affect overall N concentration or content. These data suggest RP increased soil N uptake to compensate for reduced BNF following N fertilization, indicating starter N application had no measurable benefit for legume establishment under these conditions.

Historical ecology of pinnipeds of the northern coast of the San Jorge Gulf (central Patagonia, Argentina) since the Late-Holocene

The northern coast of the San Jorge Gulf, Atlantic Patagonia, is recognised as a marine biodiversity hot spot and is designated as a priority conservation area. Among marine mammals, three species of pinnipeds inhabit the region. While South American sea lions ( Otaria flavescens) have a higher abundance and a larger number of colonies than South American fur seals ( Arctocephalus australis), a few individuals of the Southern elephant seal ( Mirounga leonina) reside in the region. Nevertheless, little is known about the abundance and distribution of these pinnipeds before the 18th century, when various extractive activities became widespread, including the unregulated exploitation of furs and oil. This study aims to examine whether the distribution and relative abundance of ancient pinnipeds differ from present-day populations. To achieve this, we conducted inter-specific identification of pinniped bone remains coming from archaeological assemblages dated from 6000 to 600 14C years BP and reviewed historical sources to contrast these retrospective data with modern ecological literature. The results suggest changes over time in the relative abundances of species within the pinniped community. The relative abundance of fur seals was greater than or equal to that of sea lions in most Late-Holocene pinniped assemblages. Additionally, fur seals have been recorded in historical and Late-Holocene periods in places where they are currently very rare. These findings are consistent with the higher relative abundance of fur seals recorded in other archaeological sites along the Patagonian coast, suggesting that modern distribution and abundance have been heavily affected by commercial hunting. This study contributes to a better understanding of the nature and magnitude of the anthropic impact on the marine ecosystem of the northern coast of the San Jorge Gulf. It also provides historical baseline information to strengthen conservation policies and restoration efforts.

Planning for Drinking Water Salinization in the U.S. Atlantic and Gulf Coast Regions

Problem, research strategy, and findings Sea-level rise will bring ocean salts inland and salinize the drinking water sources of some coastal communities. How are municipalities, regions, and states preparing for salinization? In this study I evaluated 264 climate plans and seven state water plans from the Atlantic and Gulf coasts of the United States. Of these, 65 climate adaptation plans engaged with salinization in the context of drinking water; 21 made salinity adaptation recommendations, 6 discussed implemented monitoring or modeling, and 11 discussed implemented adaptation strategies. In state water plans, some states showed considerable salinization adaptation activity, but not all linked these actions to climate adaptation. Despite seawater intrusion and salinization being widely recognized, actions were concentrated in fewer states. Maryland, Delaware, Virginia, Florida, and Texas exhibited high degrees of engagement. Louisiana, Mississippi, Alabama, and Georgia showed little evidence of planning for salinization in climate or state water plans. In the absence of federal or state governments leading on managing sea-level rise–driven salinization, evaluating and preparing for the challenge of salinization is likely to become the de facto responsibility of coastal water suppliers and well owners, who may not have the capacity, budget, or jurisdiction to adequately monitor and protect supplies. Takeaway for practice Left to individual drinking water suppliers and well owners with varying capacity for adaptation, water supply salinization driven by sea-level rise has the potential to exacerbate existing inequities in drinking water provision. Planners can contribute to adapting coastal drinking water systems by integrating monitoring and modeling into climate adaptation plans, creating partnerships that enable drinking water adaptation actions, and supporting new approaches to water funding and financing.

Astronomy, Architecture, and Landscape in the Olmec Area and Western Maya Lowlands: Implications for Understanding Regional Variability and Evolution of Orientation Patterns in Mesoamerica

Abstract In the area along the southern Gulf Coast in Mexico, a large number of previously unrecorded archaeological sites have recently been detected with the aid of lidar data, which also allowed us to determine the orientations of hundreds of structures and architectural assemblages, including many standardized complexes dated to the Early-to-Middle Formative transition. As revealed by our analyses, most orientations were based on astronomical and calendrical principles, occasionally combined with certain concepts of sacred geography. While the results of these analyses were presented in a recently published article, here we explore the potential of alignment data for addressing other questions of archaeological relevance. The distribution of particular building types and regional variations in alignment patterns in the study area suggest the existence of two somehow different cultural spheres, loosely corresponding to the areas conventionally called the Gulf Olmec region and the western Maya Lowlands. Examining pertinent evidence, we argue that it was in this area where some of the most prominent orientation groups materialized in later Mesoamerican architecture originated. We also attempt to reconstruct the paths of their diffusion, which are expected to contribute to understanding the dynamics of long-distance cultural interaction in Mesoamerica.

Exploitation of mangliculous marine fungi, Amarenographium solium, for the green synthesis of silver nanoparticles and their activity against multiple drug-resistant bacteria

Abstract The green synthesis pathway for silver nanoparticles (AgNPs) used in bacterial treatment is regarded as crucial because of its cost-effectiveness, nontoxicity, and eco-friendliness. During the present work, the mangliculous marine fungi Amarenographium solium isolated from the Arabian Gulf Coast of Saudi Arabia were utilized for the synthesis of AgNP, through the bio-reduction of aqueous silver nitrate (AgNO3) solution. The success in AgNP synthesis was visually identified by the development of dark brown color in the cell-free filtrate and was further confirmed by ultraviolet–visible spectroscopy, which showed a peak at 425 nm. The AgNPs produced were further characterized using X-ray diffraction data analysis that proved the bioreduction of silver to 20 nm, and transmission electron microscopy revealed the formation of well-dispersed spherical nanoparticles with an average mean size of 12 nm. The optimization reaction parameters of temperature, pH, and metal salt concentration were carried out and resulted in a combination of 30°C, 7 and 1.5 mM, respectively, for rapid and maximum yield production. The antibacterial activity of the produced nanoparticles was evaluated using the two-fold microdilution method and showed a minimum inhibitory concentration of 9.375 μg/mL of AgNP against multiple drug-resistant bacterial strains.

The chemical characteristics and mixing behaviors of particulate organic matter from small subtropical rivers in coastal Gulf of Mexico

Rivers transport a substantial amount of dissolved and particulate organic matter (DOM and POM) to the oceans. In estuaries, the transition between DOM and POM due to dissolution or flocculation and their chemical compositions are key in determining their remineralization potential and thus influence the biogeochemical cycling of carbon and nitrogen. While much effort has been focused on trace metals, minerals, and nutrients in estuaries, the mixing behaviors of POM have been understudied despite their biogeochemical and ecological importance. In this work, water from several rivers from the northwestern Gulf of Mexico was mixed with seawater in different proportions, and the amount as well as the chemical characteristics of POM in the mixtures was measured. POM was characterized by organic carbon and nitrogen contents, carbon and nitrogen stable isotopes (δ13C and δ15N), and total hydrolyzable amino acids (THAA). The results showed that POM in most cases behaved conservatively after the mixing of river water with seawater. However, rapid POM formation was observed in one of the seven experiments, which was conducted in 2021 with Mission River water, a relatively pristine river. The amount of particulate organic carbon formed in this experiment (41 μM) was 12% of the dissolved organic carbon at a salinity of 6. The formed POM was more depleted in 13C and had a higher POC/PON ratio than expected for conservative mixing, suggesting that terrestrial DOM, likely sourced from lignins and/or lipids, may have contributed to the flocculates. The short duration of these laboratory experiments under dim or dark conditions excludes the potential effects from biotic or photochemical processes, and thus the observations should be attributed to the rapid physical transformation of DOM to POM or flocculation, particularly when the riverine OM is contributed more from terrestrial sources than in situ production. Overall, although POM mostly behaved conservatively, substantial POM can be produced from DOM under right conditions, and these results shed new light on the biogeochemical cycling of organic matter in subtropical estuaries.

FERC Needs Court's Help on Pipelines in 2024

Late in 2023, Keith Goldberg from Law360 wrote that 2024 would be a year where the courts could show the Federal Energy Regulatory Commission (FERC) the way out of its dilemma regarding how to certificate new natural gas pipelines in an era dominated by climate change exigencies. He described three cases where the courts could do so—one involving a pipeline upgrade to New York City and two others dealing with short pipelines tied to liquefied natural gas (LNG) export facilities in the U.S. Gulf Coast.1 To Goldberg, there are “signs that courts are growing impatient with the agency's continued lack of clarity on how it conducts [climate impact] reviews” tied to its pipeline certification duties. The courts need to intervene. FERC has quite evidently lost its way.

A late refugium for Classopollis in the Paleocene Lower Wilcox Group along the Texas Gulf Coast

Abstract We report a new ecological refugium for the Cheirolepidiaceae family (pollen form genus Classopollis) in the Paleocene Lower Wilcox Group in the Gulf Coast of southeastern Texas based on palynological analysis of four wells. The Cheirolepidiaceae were once thought to have gone extinct at the Cretaceous–Paleogene (K/Pg) boundary or earlier in North America; however, similar ecological refugia for this family in the Paleocene have previously been reported in China, Argentina, and potentially the Rocky Mountains of the United States. The highest relative abundances of Classopollis pollen were found in delta front, lagoon, and shoreface depositional paleoenvironments marked by high mud-fraction Sr/Ba (a geochemical proxy for salinity), and abundances generally increased down section in older Paleocene strata. The high relative abundance of Classopollis pollen in the well samples, the rarity of reworked Mesozoic palynomorphs, the generally good preservation of Classopollis pollen, and the similarity of Classopollis fluorescence spectra to other in situ Paleocene pollen all provide strong evidence for the survival of the Cheirolepidiaceae family in the coastal salt marshes of Texas through at least the late Paleocene.

Characterization of Chinese Tallow Invasion in the Southern United States

Chinese tallow is a non-native invasive tree expanding in range and abundance throughout the southern United States. Several biogeographical studies mapping tallow distribution and examining key underlying environmental factors relied on the U.S. Forest Service Forest Inventory and Analysis (FIA) data, representing forestlands at scales of ~2400 ha. However, given that most invasive trees, like tallow, are cosmopolitan and dynamic in nature, FIA data fails to capture the extent and severity of the invasion especially outside areas classified as forestlands. To develop tallow maps that more adequately depict its distribution at finer spatial scales and to capture observations in non-forestlands, we combined verified citizen science observations with FIA data. Further, we described spatiotemporal patterns and compared citizen science to FIA and other previously published distribution maps. From our work, although tallow is prevalent in the south, Louisiana, Texas, and Mississippi were the most invaded states. Tallow was associated with flatwoods and prairie grasslands of the Gulf Coast. Annual extreme minimum temperatures of less than −12.2 °C (10 °F) represented the northern limit of naturalized tallow populations. Tallow’s northward and inland expansion was captured in citizen science and FIA data, indicating a tallow spread rate ranging from 5 to 20 km annually over the last decade. Systematic sampling, such as FIA, and citizen science data both have their own unique pitfalls. However, the use of citizen science data can complement invasive plant distribution mapping, especially when combined with data from established systematic monitoring networks. This approach provides for a more complete understanding of invasive tree extent and spatiotemporal dynamics across large landscapes.

Application of a Geochemically Informed Leak Detection (GILD) Model to CO2 Injection Sites on the United States Gulf Coast

The Gulf Coast region possesses great potential for CO2 enhanced oil recovery (EOR) and CO2 storage. A geochemically informed leak detection (GILD) model has been applied to CO2 injection sites on the Gulf Coast with considerations of measurement variability. The Jasper aquifer in Montgomery County, Texas, was chosen to demonstrate the method. Based on background data from wells in the area, combinations of mineral and fluid compositions were used to create 23 scenarios for the geochemical model. The output from the geochemical model was used to identify sensitive monitoring species, and response functions were generated for these as a function of the CO2 leakage concentration. The sources of measurement variability for background conditions were characterized from the Jasper aquifer background data, and then normalized using the coefficient of variation of each species across the monitoring wells. Bayesian belief network (BBN) models were constructed, and measurement variability of different levels were added to compare leak detection probabilities. Increasing measurement variability decreased the power to detect a leak of a given size. For a moderately high CO2 concentration of 0.2 mol/kg, the probability of detecting this leakage effect using pH as the monitoring variable in an aquifer with calcite decreases from 98% (no measurement variability) to 61% (medium variability) to 33% (high variability). The loss in power of the sampling protocol with increasing measurement variability is similar in magnitude when Ca2+ or HCO3− is used as the monitoring parameter, but only for aquifers with calcite.