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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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120 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Climate Change, Extreme Weather Events, and Fungal Disease Emergence and Spread

Empirical evidence from multiple sources show the Earth has been warming since the late 19th century. More recently, evidence for this warming trend is strongly supported by satellite data since the late 1970s from the cryosphere, atmosphere, oceans, and land that confirms increasing temperature trends and their consequences (e.g., reduced Arctic sea ice, rising sea level, ice sheet mass loss, etc.). At the same time, satellite observations of the Sun show remarkably stable solar cycles since the late 1970s, when direct observations of the Sun's total solar irradiance began. Numerical simulation models, driven in part by assimilated satellite data, suggest that future-warming trends will lead to not only a warmer planet, but also a wetter and drier climate depending upon location in a fashion consistent with large-scale atmospheric processes. Continued global warming poses new opportunities for the emergence and spread of fungal disease, as climate systems change at regional and global scales, and as animal and plant species move into new niches. Our contribution to this proceedings is organized thus: First, we review empirical evidence for a warming Earth. Second, we show the Sun is not responsible for the observed warming. Third, we review numerical simulation modeling results that project these trends into the future, describing the projected abiotic environment of our planet in the next 40 to 50 years. Fourth, we illustrate how Rift Valley fever outbreaks have been linked to climate, enabling a better understanding of the dynamics of these diseases, and how this has led to the development of an operational predictive outbreak model for this disease in Africa. Fifth, We project how this experience may be applicable to predicting outbreaks of fungal pathogens in a warming world. Lastly, we describe an example of changing species ranges due to climate change, resulting from recent warming in the Andes and associated glacier melt that has enabled amphibians to colonize higher elevation lakes, only to be followed shortly by the emergence of fungal disease in the new habitats.

Tucker, Compton J.↗
NASA NTRS2011

Goddard DEVELOP Students: Using NASA Remote Sensing Technology to Study the Chesapeake Bay Watershed

The DEVELOP National Program is an Earth Science research internship, operating under NASA s Applied Sciences Program. Each spring, summer, and fall, DEVELOP interns form teams to investigate Earth Science related issues. Since the Fall of 2003, Goddard Space Flight Center (GSFC) has been home to one of 10 national DEVELOP teams. In past terms, students completed a variety of projects related to the Applied Sciences Applications of National Priority, such as Public Health, Natural Disasters, Water Resources, and Ecological Forecasting. These projects have focused on areas all over the world, including the United States, Africa, and Asia. Recently, Goddard DEVELOP students have turned their attention to a local environment, the Chesapeake Bay Watershed. The Chesapeake Bay Watershed is a complex and diverse ecosystem, spanning approximately 64,000 square miles. The watershed encompasses parts of six states: Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia, as well as the District of Columbia. The Bay itself is the biggest estuary in the United States, with over 100,000 tributaries feeding into it. The ratio of fresh water to salt water varies throughout the Bay, allowing for a variety of habitats. The Bay s wetlands, marshes, forests, reefs, and rivers support more than 3,600 plant and animal species, including birds, mammals, reptiles, amphibians, fish, and crabs. The Bay is also commercially significant. It is ranked third in the nation in fishery catch, and supplies approximately 500 million pounds of seafood annually. In addition to its abundant flora and fauna, the Chesapeake Bay watershed is home to approximately 16.6 million people, who live and work throughout the watershed, and who use its diverse resources for recreational purposes. Over the past several decades, the population throughout the watershed has increased rapidly, resulting in land use changes, and ultimately decreasing the health of the Chesapeake Bay Watershed. Over the course of 2009-2010, student teams carried out two independent research projects focused on the Chesapeake Bay Watershed. The first investigated the threat of invasive species to forests in Maryland. The second investigated the detection of winter cover crops throughout the watershed from satellite data.

Moore, Rachel↗
NASA NTRS2019

Spatiotemporal Monitoring of Hydrilla [Hydrilla verticillata (L. f.) Royle] to Aid Management Actions

Hydrilla is an invasive aquatic plant that has rapidly spread through many inland water bodies across the globe by outcompeting native aquatic plants. Drinking water supply, power generation, and recreational use of lakes are threatened by the spread of this invasive species. Moreover, hydrilla serves as a host for an epiphytic, toxic cyanobacteria known to be the causative agent of the neurodegenerative disease called avian vacuolar myelinopathy, which affects waterfowl, raptors, and amphibians. The early detection of hydrilla infestation is very important to reduce the costs associated with control and removal efforts of this invasive species. Therefore, this study was aimed at developing a rapid, frequent, and large-scale tool for monitoring and predicting spatial extent of hydrilla habitat. This was achieved by integrating in situ and Landsat 8 OLI satellite data for Lake J. Strom Thurmond, the largest US Army Corps of Engineers Lake east of the Mississippi River located on the Georgia/South Caroline border. The predictive model incorporated remote sensing reflectance, Secchi disk depth (SDD), light attenuation coefficient (Kd), maximum depth of colonization (Zc), and percentage of light available through water column (PLW). The model predicted ideal habitat for hydrilla featuring high SDD, low values of Kd, high Zc and PLW. Final analysis showed that hydrilla starts growing in April, reaches peak around October, begins retreating in the following months, and disappears in February. Additionally, physical meteorological factors were analyzed and were found to be closely associated with hydrilla extent. Management agencies can use these results to not only to plan future removal efforts, but also evaluate and adapt their current mitigation efforts.

Percentage of light available through the water co↗
NASA NTRS2021

Tropicalization of Temperate Ecosystems in North America: The Northward Range Expansion of Tropical Organisms in Response to Warming Winter Temperatures

Tropicalization is a term used to describe the transformation of temperate ecosystems by poleward-moving tropical organisms in response to warming temperatures. In North America, decreases in the frequency and intensity of extreme winter cold events are expected to allow the poleward range expansion of many cold-sensitive tropical organisms, sometimes at the expense of temperate organisms. Although ecologists have long noted the critical ecological role of winter cold temperature extremes in tropical–temperate transition zones, the ecological effects of extreme cold events have been understudied, and the influence of warming winter temperatures has too often been left out of climate change vulnerability assessments. Here, we examine the influence of extreme cold events on the northward range limits of a diverse group of tropical organisms, including terrestrial plants, coastal wetland plants, coastal fishes, sea turtles, terrestrial reptiles, amphibians, manatees, and insects. For these organisms, extreme cold events can lead to major physiological damage or landscape-scale mass mortality. Conversely, the absence of extreme cold events can foster population growth, range expansion, and ecological regime shifts. We discuss the effects of warming winters on species and ecosystems in tropical–temperate transition zones. In the 21st century, climate change-induced decreases in the frequency and intensity of extreme cold events are expected to facilitate the poleward range expansion of many tropical species. Our review highlights critical knowledge gaps for advancing understanding of the ecological implications of the tropicalization of temperate ecosystems in North America.

climate change↗
DOE OSTI2020

Eurycea lucifuga (Cave Salamander). Diet.

Eurycea lucifuga is a common and widespread facultative inhabitant of caves and springs in the southeastern and central United States (Powell et al. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. Houghton Mifflin Harcourt, Boston, Massachusetts. 512 pp.). This species is known to feed on a variety of invertebrates, such as snails, crustaceans, beetles, and flies (Peck 1974. Nat. Speleol. Soc. Bull. 36:7–10). Although several millipede species also can serve as prey for E. lucifuga, some are presumably avoided due to the presence of defensive secretions (e.g., Abacionidae, Paradoxosomatidae). Captive feeding trials and field study show that E. lucifuga do not actively prey upon cave-obligate Tetracion millipedes, which produce defensive secretions comprised primarily of the compound p-cresol (Peck and Richardson 1976. Annales de Speleologie 31:175–182). On the other hand, Pseudotremia millipedes, which do not possess chemical defenses, are a significant component of the diet of cave-dwelling E. lucifuga (Peck and Richardson 1976, op. cit.)

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

NECTURUS MACULOSUS (Common Mudpuppy). NESTING

Common Mudpuppies (Necturus maculosus maculosus) are the most widespread and wellstudied of the Proteidae, ranging from northern Georgia into eastern Canada and west to the Great Plains. Despite this extensive range, most of our knowledge of life history traits for mudpuppies is based on studies occurring in the northern half of its range, specifically the Great Lakes region. Little is known regarding life history traits in the southern portion of its range. In Tennessee, N. maculosus is thought to occur statewide in permanent streams, rivers, and likely in reservoirs and lakes. Literature suggests that parturition and nest-guarding in N. maculosus maculosus occurs in late winter through spring, but there are no published observations to verify this in Tennessee (Pasachnik and Niemiller 2011. In Niemiller and Reynolds [eds.], The Amphibians of Tennessee, pp. 231-233. University of Tennessee Press, Knoxville, Tennessee). Here, we report four observations of N. maculosus maculosus nests that were discovered while conducting snorkel surveys and lifting cover objects opportunistically for aquatic salamanders from 2011 to 2017, and approximate timing of laying in three river tributaries to the Tennessee River.

Nelson, Stephen K.↗
DOE OSTI2024

Alkaloids are associated with increased microbial diversity and metabolic function in poison frogs

Shifts in host-associated microbiomes can impact both host and microbes. It is of interest to understand how perturbations, like the introduction of exogenous chemicals, impact microbiomes. In poison frogs (family Dendrobatidae), the skin microbiome is exposed to alkaloids that the frogs sequester for defense. These alkaloids are antimicrobial; however, their effect on the frogs’ skin microbiome is unknown. To test this, we characterized microbial communities from field-collected dendrobatid frogs. Then, we conducted a laboratory experiment to monitor the effect of the alkaloid decahydroquinoline (DHQ) on the microbiome of two frog species with contrasting alkaloid loads in nature. In both datasets, we found that alkaloid-exposed microbiomes were more phylogenetically diverse, with an increase in diversity among rare taxa. Further, to better understand the isolate-specific response to alkaloids, we cultured microbial isolates from poison frog skin and found that many isolates exhibited enhanced growth or were not impacted by the addition of DHQ. To further explore the microbial response to alkaloids, we sequenced the metagenomes from high- and low-alkaloid frogs and observed a greater diversity of genes associated with nitrogen and carbon metabolism in high-alkaloid frogs. From these data, we hypothesized that some strains may metabolize the alkaloids. We used stable isotope tracing coupled to nanoSIMS (nanoscale secondary ion mass spectrometry), which supported the idea that some of these isolates are able to metabolize DHQ. Together, these data suggest that poison frog alkaloids open new niches for skin-associated microbes with specific adaptations, such as alkaloid metabolism, that enable survival in this environment.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Short-term exposure to elevated suspended sediment increases oxygen uptake of gilled larval Eastern Hellbender ( Cryptobranchus alleganiensis ) salamanders

Freshwater ecosystems are increasingly impacted by anthropogenic elevated levels of suspended sediment that may negatively affect aquatic organisms, including salamanders. Although increasing fine sediment in streams has been suggested as a reason for population declines, to date no study has empirically assessed the effect of suspended sediment on gilled larval Eastern Hellbenders (Cryptobranchus alleganiensis (Sonnini de Manoncourt and Latreille, 1801)), a critical life-history stage and a species of conservation concern. We used custom respirometers to elucidate effects of suspended sediments on larval Eastern Hellbender oxygen uptake in trials conducted in situ in Georgia (USA) streams. Mean oxygen uptake increased and was significantly higher in trials when larval salamanders were exposed to suspended sediment (mean = 5.06 mg O 2 /L for 800 mg/L of sediment treatment vs. 2.25 mg O 2 /L for 0.00 mg/L of sediment control). This may indicate elevated physiological stress in response to short-term exposure to suspended sediments. Qualitatively, individuals in both groups exhibited rocking behavior in response to low oxygen (hypoxia), albeit at different frequencies (sediment exposure = 7.6 rocks/min and control = 2.1 rocks/min). Larval salamanders may be able to temporarily compensate for low oxygen through increased rocking behavior when high suspended sediment loads are present, with future respirometry research needed.

hypoxia↗
NASA NTRS1927

The Francois Villiers marine pursuit airplane

A traditional biplane design allows this craft to function with the speed and maneuverability necessary to perform as a pursuit aircraft while also being able to land on water. It featured retractable landing gear for water landings. It was powered with a 450 HP. Lorraine-Dietrich engine.

AMPHIBIANS - VILLIERS 2 (FR )↗