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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

The Anaerobic Fungi: Challenges and Opportunities for Industrial Lignocellulosic Biofuel Production

Lignocellulose is a promising feedstock for biofuel production as a renewable, carbohydrate-rich and globally abundant source of biomass. However, challenges faced include environmental and/or financial costs associated with typical lignocellulose pretreatments needed to overcome the natural recalcitrance of the material before conversion to biofuel. Anaerobic fungi are a group of underexplored microorganisms belonging to the early diverging phylum Neocallimastigomycota and are native to the intricately evolved digestive system of mammalian herbivores. Anaerobic fungi have promising potential for application in biofuel production processes due to the combination of their highly effective ability to hydrolyse lignocellulose and capability to convert this substrate to H2 and ethanol. Furthermore, they can produce volatile fatty acid precursors for subsequent biological conversion to H2 or CH4 by other microorganisms. The complex biological characteristics of their natural habitat are described, and these features are contextualised towards the development of suitable industrial systems for in vitro growth. Moreover, progress towards achieving that goal is reviewed in terms of process and genetic engineering. In addition, emerging opportunities are presented for the use of anaerobic fungi for lignocellulose pretreatment; dark fermentation; bioethanol production; and the potential for integration with methanogenesis, microbial electrolysis cells and photofermentation.

pretreatment↗
NASA NTRS1989

The evolution of ecological tolerance in prokaryotes

The ecological ranges of Archaeobacteria and Eubacteria are constrained by a requirement for liquid water and the physico-chemical stability limits of biomolecules, but within this broad envelope, prokaryotes have evolved adaptations that permit them to tolerate a remarkable spectrum of habitats. Laboratory experiments indicate that prokaryotes can adapt rapidly to novel environmental conditions, yet geological studies suggest early diversification and long-term stasis within the prokaryotic kingdoms. These apparently contradictory perspectives can be reconciled by understanding that, in general, rates and patterns of prokaryotic evolution reflect the developmental history of the Earth's surface environments. Our understanding of modern microbial ecology provides a lens through which our accumulating knowledge of physiology, molecular phylogeny and the Earth's history can be integrated and focussed on the phenomenon of prokaryotic evolution.

NASA Discipline Number 52-30↗
NASA NTRSDate not supplied

Lessons from Earth Aerobiology for Venus Astrobiology

Venus’s clouds have often suggested as a possible habitat. The constraints governing putative airborne life in such a habitat in turn inform priorities and strategies for remote and in situ exploration, methods by which resulting biosignatures might be detected, exoplanet habitability assessment, and planetary protection concerns. Lessons drawn from studying Earth’s aerobiosphere can help improve this understanding. There are altitude ranges within Venus’s clouds in which temperature, pressure, particle size, and radiation appear to be within the limits of microbial life on Earth, and life cycles involving S- and Fe-based redox metabolism have been proposed. However, given the lack of a habitable surface reservoir, a long-term stable Venus aerobiosphere would require that the reproduction rate of the airborne microbes be faster than the settling rate of airborne microbes due to gravity, or eventually the population would be depleted; put another way, the mean generation time would need to exceed the mean residence time. This creates a joint constraint of aerosol dynamics, potential nutrient availability and energy influx, and bioenergetic costs such as desiccation and radiation damage. Even at an optimistic estimate of 75% H2SO4, Venus aerosol water activity (aw) is still ~0.02, far below the observed microbial growth limit of ~0.6. Long-term desiccation with brief spurts of repair and growth in response to transient water influx, such as from volcanism, is the most likely model for Earth-like life on Venus – a ‘desert bloom’ scenario. Several high-priority science goals – cloud aerosol composition, internal radiative flux, and aerosol residence time and circulation models – thus will also improve our understanding of Venus in an astrobiology context. In Earth’s troposphere, warm water clouds can carry 103 – 105 cells/mL, some metabolically active. However, Earth’s stratospheric sulfate aerosol layer may be a better analogue: supercooled sulfuric acidaerosols (acid weight fraction 0.6 – 0.85, 0.1 – 1 μm diameter, 0.1 – 1 cm-3) with little water activity, long residence times, high UV radiation, and only sporadic influx from surface particle sources. Though ‘hot spots’ can occur associated with tropospheric mixing, viable cells in stratospheric samples are rare (~102 cells/m3), and primarily inactive forms such as spores. It is not yet clear whether such bioaerosols are associated with sulfate aerosols or simply co-located, and reproduction in situ has not yet been observed. In this model of a sparse, largely dormant Venus ecosystem, a single transect on descent is likely to pass through a low-water, inactive region, missing potential signs of habitability or biosignatures. A targeted strategy would sample through an aerial region with some upwelling from surface sources, andtake multiple transects separated in time and space. This is compatible with other in situ science goals seeking to understand the dynamics and heterogeneities of Venus’s clouds.

Lower atmosphere↗
NASA NTRS1998

Site Selection for Mars Exopaleontology in 2001

The microbial fossil record encompasses a wide range of information, including cellular remains, stromatolites, biofabrics, trace fossils, biominerals and chemofossils. The preservation of fossils is strongly influenced by the physical, chemical and biological factors of the environment which, acting together, ultimately determine the types of information that will be captured and retained in the rock record. The critical factor in assessing the suitability of a site for a microbial fossil record is the paleoenvironment. The reconstruction of ancient sedimentary environments usually requires the integration of a wide variety of geological information, including the shape, geometry and internal structure of sedimentary deposits, their mineralogy, and geochemistry. For Mars, much of our knowledge about past environments is based on orbital imaging of geomorphic features. This evidence provides an important context and starting point for site selection. However, our knowledge of the martian surface is quite limited, and a major goal of the upcoming exploration effort is to reconstruct the history of Martian volatiles, climate, and hydrology as a context for the exploration for past or present life. Mineralogical mapping from orbit will be an important key in this effort. In exploring for evidence of past life, terrestrial experience suggests that the long-term preservation of biological information as fossils occurs under a fairly narrow range of geological conditions that are well known to paleontologists (1). In detrital sedimentary systems, microbial fossilization is favored by rapid burial in fine-grained, clay-rich sediments. In chemical sedimentary systems, preservation is enhanced by rapid entombment in fine-grained chemical precipitates. For long term preservation, host rocks must be composed of stable minerals that resist chemical weathering, and which form an impermeable matrix and closed chemical system that can protect biosignatures from alteration during subsequent diagenetic change or metamorphism. In this context, host rocks composed of highly ordered, chemically-stable mineral phases, like silica (forming cherts) or phosphate (forming phosphorites), are especially favored. Such lithologies tend to have very long crustal residence times and (along with carbonates and shales), are the most common host rocks for the Precambrian microfossil record on Earth. If we assume that a subsurface hydrosphere has been present throughout martian history, then life could have originated there at any time, perhaps emerging at the surface periodically when climate changes, induced by external forcing or endogenous processes (e.g. volcanism), allowed liquid water to exist at the surface. The recent discovery of subsurface chemolithoautotrophic organisms which are capable of synthesizing organic substrates from C02 and H2 liberated from the aqueous weathering of basalt, is especially. relevant as a model for martian life. While a subsurface habitable zone may yet exist on Mars, access to such environments will likely require drilling to depths of several kilometers. Given the technological challenge of deep drilling, this is unlikely to occur prior to human missions. So, even if there is extant life on Mars today in subsurface habitats, it may be much easier to find its fossil counterparts in ancient deposits exposed at the surface. In exploring for a fossil record in subsurface environments on Mars there are several geological situations that may provide access to the appropriate materials. These include 1) ejecta from impact craters, 2) talus slopes, debris flows or alluvial fans developed below the walls of deep canyons, and 3) the deposits of outflood channels. Examples of aqueous mineral deposits of formed in subsurface environments that could harbor a microbial fossil record include such things as cements in detrital sedimentary rocks, low temperature diagenetic minerals deposited in veins, or filling vesicles in volcanic rocks, and hydrothermal deposits formed below the upper temperature limit for life (about 160 degrees C). There are many sites within the present latitudinal constraints for the 2001 mission (15 deg S to 30 deg N) that meet these requirements. But the practical problem with these kinds of deposits is that they tend to be disseminated, making up only a small percentage of a host rock. Even with mineralogical information provided by the Thermal Emission Spectrometer (TES) presently in orbit around Mars, predicting their occurrence ahead of time may be quite difficult. The deposits of surficial aqueous sedimentary systems are likely to provide the largest targets for site selection in 2001. Of these, the deposits of hydrothermal systems (subaerial and subaqueous thermal springs) have been discussed previously. It is likely that hydrothermal systems were widespread on Mars early in its history and a number of common geo-tectonic settings on Mars are likely to have hosted hydrothermal activity. Most of these are represented within the latitudinal constraints presently identified for 2001. However, the deposits of surface spring systems are likely to be difficult to find as well. On Earth, exposure areas for hydrothermal spring mounds are typically a few square kms, less than a single TES pixel. But such deposits may be quite abundant within some volcanic terrains, It is estimated, for example, that between 15-20% of the floor of Yellowstone caldera is covered by thermal spring deposits. In such abundances, subaerial sinters could well be detected by TES. Where exposed, the shallow subsurface portions of these systems may be quite a lot larger (perhaps tens of square kms), although (as noted above) mineralization may be finely disseminated in the basement rock, making remote detection more difficult. Paleolake Basins. There are a large number of potential paleolake basins on Mars (inclusive of impact craters and volcanic calderas) that have been previously identified using Viking images. Most of these lie in the southern highlands beyond the l5 deg S constraint for 2001. However, deposits of paleolakes may offer the largest and most easily identified exopaleontological targets from orbit. Based on a variety of arguments, some workers have suggested that there was once an ancient ocean on the northern plains, and some sites of interest (potential shoreline terraces) fall within the 30 deg N constraint. From a paleontological standpoint the most interesting places of this type are terminal paleolake basins which are likely to have been both saline and alkaline. Models by Schaefer suggest such environments could be widespread on Mars. The conditions in terminal lake basin settings favor widespread chemical sedimentation, an important condition for microbial fossilization. Important lithological targets for a microbial fossil record in terminal lake basins include spring-deposited carbonates, shoreline cements, a wide variety of evaporite minerals and fine-grained detrital sediments including shales, marls, and water-lain volcanic ash deposits. In developing a strategy to explore for ancient hydrothermal deposits on Mars, we can learn from the methods that have been developed by explorationists to explore for economic mineral deposits on Earth. Due to their simple mineralogy, hydrothermal deposits can often be detected using remote sensing methods. Common thermal spring mineral assemblages include silica, carbonate, and various metallic oxides and sulfides. But there are also a number of diagnostic silicate minerals, including clays, formed by the hydrothermal alteration of country rocks. These hydrothermal minerals have characteristic spectral signatures that could be detected from Mars orbit using high resolution infrared remote sensing methods. In playa lake settings, evaporite deposits often form a predictable "bull's eye" pattern with carbonates being deposited in marginal basin areas, and sulfates and halides occurring progressively more basinward. The floors of some impact craters on Mars, such as "White Rock" and Bequeral Crater (see Oxia Palus NE, Site 148), have floor deposits that could be evaporites, inclusive of carbonates. Evaporite minerals possess characteristic spectral signatures in the infrared and could similarly be identified from Mars orbit using high resolution remote sensing methods. Clearly, utilization of TES data will be important for optimizing site selection for Exopaleontology, and every effort should be made to benefit from that data before a final decision is made.

Farmer, Jack↗
NASA NTRS2013

Advanced Planetary Protection Technologies for the Proposed Future Mission Set

Planetary protection is the discipline of protecting solar system objects from harmful contamination resulting from the activities of interplanetary spacecraft, and of similarly protecting the Earth from uncontrolled release of a putative extra-terrestrial organism from returned extra-terrestrial samples. Planetary protection requirements for Mars are becoming further refined as more is understood about the nature of the Martian environment as a potential habitat. Likewise, increased understanding of the limits of life on Earth is informing planetary protection policy. This presentation will discuss recent technology developments, ongoing work and future challenges of implementing planetary protection for the proposed future mission set.

Europa↗
DOE OSTI2024

Microbial Proxies for Anoxic Microsites Vary with Management and Partially Explain Soil Carbon Concentration

Anoxic microsites are potentially important but unresolved contributors to soil organic carbon (C) storage. How anoxic microsites vary with soil management and the degree to which anoxic microsites contribute to soil C stabilization remain unknown. Sampling from four long-term agricultural experiments in the central United States, we examined how anoxic microsites varied with management (e.g., cultivation, tillage, and manure amendments) and whether anoxic microsites determine soil C concentration in surface (0–15 cm) soils. We used a novel approach to track anaerobe habitat space and, hence, anoxic microsites using DNA copies of anaerobic functional genes over a confined volume of soil. No-till practices inconsistently increased anoxic microsite extent compared to conventionally tilled soils, and within one site organic matter amendments increased anaerobe abundance in no-till soils. Across all long-term tillage trials, uncultivated soils had ~2–4 times more copies of anaerobic functional genes than their cropland counterparts. Finally, anaerobe abundance was positively correlated to soil C concentration. Even when accounting for other soil C protection mechanisms, anaerobe abundance, our proxy for anoxic microsites, explained 41% of the variance and 5% of the unique variance in soil C concentration in cropland soils, making anoxic microsites the strongest management-responsive predictor of soil C concentration. Our results suggest that careful management of anoxic microsites may be a promising strategy to increase soil C storage within agricultural soils.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2017

Forward Contamination of Ocean Worlds: A Stakeholder Conversation

A fundamental requirement for space missions designed to touch “potential habitats” is the single number 10−4, the allowable probability of a single Earth organism contaminating the potential habitat. Many aspects of a mission that affect its complexity and cost – hardware design and manufacture, assembly and test, and mission operations – are driven by this value, so it is important, on the threshold of an era of exploring ocean worlds, to have confidence in it. Yet despite its long pedigree and occasional reviews, we find that the current requirement lacks programmatically defensible justification. At issue are three weaknesses: 1) microbial biology, in particular the science of extremophiles, is a rapidly changing field; 2) forward contamination is both a scientific and an ethical issue, yet no ethics-based conversation is apparent within policy-setting circles; 3) because of these two factors, policy-setting cannot be static. We review the history of the requirement; how the evolving understanding of biology could drive it up or down; how the forward-contamination hazard relates to risk-management practice and to the ethics profession; and how a contemporary stakeholder conversation could adapt lessons already learned by other fields.

Waltemathe, Michael↗
NASA NTRSDate not supplied

A Lunar Ground Truth of Microbes that are Integral to Sustaining Biological Life Support Systems

A lunar outpost such as Gateway or a Mars transit vehicle will use a semi-closed to closed loop biological life support system (BLSS) adapted for microgravity and high levels of radiation. A moon habitat will likely exist under partial gravity conditions and sustained levels of high radiation as a semi-closed loop system able to get resources from Earth via Gateway. Additionally, the moon will act as a closed-loop testbed for Mars habitat operations and will employ various elements of in situ resource utilization (ISRU). Perhaps the longest running BLSS collective study to date is that of the European MELiSSA (Micro Ecological Life Support System Alternative) project, a circular life support system, established to gain knowledge on regenerative systems aimed at the highest degree of autonomy to produce food, water and oxygen from mission wastes. This setup has evaluated the use of discrete microbial compartments and a higher plant compartment to carry out the necessary life support functions to support crew. Such compartments utilize thermophilic anaerobes to break down human and inedible plant wastes, photoheterotrophic bacteria that can further metabolize volatile fatty acids, nitrifying bacteria that can convert ammonium to plant and microalgae available nitrates, and photoautotrophic bacteria and higher plants which will convert carbon dioxide to oxygen, purify water, and provide food for human consumption. This being the most advanced BLSS model example to date -aside from the Yuegong-1, Chinese Lunar Palace- with the most defined compartment composition, and the assumption that other BLSSs will build upon such models, it becomes relevant to study the effects of the lunar environment upon the microbes that are integral to a BLSS. In ramping up to advanced stage BLSS systems, relatively simple experiments can be conducted on Artemis missions using continuous culturing and sampling of the model microbes, subsequently subjected to DNA sequencing for mutational analysis monitoring and chemical analysis to assess the sustained ability to carry out their hallmark biochemical processes efficiently. A suite of microbes should be assessed, prioritizing those with the duel capacity to be utilized in an BLSS and the ability to biochemically facilitate ISRU goals, such as the ability to transform the biogeochemistry of Moon or Martian regolith into materials that can support crop growth or extract elements of industrial significance such as aluminum or iron.

Biological Life Support Systems↗
NASA NTRS1994

Suitability of Gray Water for Hydroponic Crop Production Following Biological and Physical Chemical and Biological Subsystems

The water present in waste streams from a human habitat must be recycled in Controlled Ecological Life Support Systems (CELSS) to limit resupply needs and attain self-sufficiency. Plants play an important role in providing food, regenerating air, and producing purified water via transpiration. However, we have shown that the surfactants present in hygiene waste water have acute toxic effects on plant growth (Bubenheim et al. 1994; Greene et al., 1994). These phytotoxic affects can be mitigated by allowing the microbial population on the root surface to degrade the surfactant, however, a significant suppression (several days) in crop performance is experienced prior to reaching sub-toxic surfactant levels and plant recovery. An effective alternative is to stabilize the microbial population responsible for degradation of the surfactant on an aerobic bioreactor and process the waste water prior to utilization in the hydroponic solution (Wisniewski and Bubenheim, 1993). A sensitive bioassay indicates that the surfactant phytotoxicity is suppressed by more than 90% within 5 hours of introduction of the gray water to the bioreactor; processing for more than 12 hours degrades more than 99% of the phytotoxin. Vapor Compression Distillation (VCD) is a physical / chemical method for water purification which employees sequential distillation steps to separate water from solids and to volatilize contaminants. The solids from the waste water are concentrated in a brine and the pure product water (70 - 90% of the total waste water volume depending on operating conditions) retains non of the phytotoxic effects. Results of the bioassay were used to guide evaluations of the suitability of recovered gray water following biological and VCD processing for hydroponic lettuce production in controlled environments. Lettuce crops were grown for 28 days with 100% of the input water supplied with recovered water from the biological processor or VCD. When compared with the growth of plants in control hydroponic solution containing pure deionized water, no growth difference could be measured resulting from any of the recovered water treatments. Both biological treatment and VCD offer alternative technology approaches to recovering water from waste streams appropriate for input into a crop production system. A high level of crop performance (food, air, and water production) can be maintained with either processor; selection decisions can be based on other factors regarding system integration.

Bubenheim, David L.↗
DOE OSTI2021

Resistance, Resilience, and Recovery of Dryland Soil Bacterial Communities Across Multiple Disturbances

Dryland ecosystems are sensitive to perturbations and generally slow to recover post disturbance. The microorganisms residing in dryland soils are especially important as they contribute to soil structure and nutrient cycling. Disturbance can have particularly strong effects on dryland soil structure and function, yet the natural resistance and recovery of the microbial components of dryland soils has not been well documented. In this study, the recovery of surface soil bacterial communities from multiple physical and environmental disturbances is assessed. Samples were collected from three field sites in the vicinity of Moab, UT, United States, 6 to 7 years after physical and climate disturbance manipulations had been terminated, allowing for the assessment of community recovery. Additionally, samples were collected in a transect that included three habitat patches: the canopy zone soils under the dominant shrubs, the interspace soils that are colonized by biological soil crusts, and edge soils at the plot borders. Field site and habitat patch were significant factors structuring the bacterial communities, illustrating that sites and habitats harbored unique soil microbiomes. Across the different sites and disturbance treatments, there was evidence of significant bacterial community recovery, as bacterial biomass and diversity were not significantly different than control plots. There was, however, a small number of 16S rRNA gene amplicon sequence variants that distinguished particular treatments, suggesting that legacy effects of the disturbances still remained. Taken together, these data suggest that dryland bacterial communities may possess a previously unappreciated potential to recover within years of the original disturbance.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1997

Biodiversity within hot spring microbial mat communities: molecular monitoring of enrichment cultures

We have begun to examine the basis for incongruence between hot spring microbial mat populations detected by cultivation or by 16S rRNA methods. We used denaturing gradient gel electrophoresis (DGGE) to monitor enrichments and isolates plated therefrom. At near extincting inoculum dilutions we observed Chloroflexus-like and cyanobacterial populations whose 16S rRNA sequences have been detected in the 'New Pit' Spring Chloroflexus mat and the Octopus Spring cyanobacterial mat. Cyanobacterial populations enriched from 44 to 54 degrees C and 56 to 63 degrees C samples at near habitat temperatures were similar to those previously detected in mat samples of comparable temperatures. However, a lower temperature enrichment from the higher temperature sample selected for the populations found in the lower temperature sample. Three Thermus populations detected by both DGGE and isolation exemplify even more how enrichment may bias our view of community structure. The most abundant population was adapted to the habitat temperature (50 degrees C), while populations adapted to 65 degrees C and 70 degrees C were 10(2)- and 10(4)-fold less abundant, respectively. However, enrichment at 70 degrees C favored the least abundant strain. Inoculum dilution and incubation at the habitat temperature favored the more numerically relevant populations. We enriched many other aerobic chemoorganotrophic populations at various inoculum dilutions and substrate concentrations, most of whose 16S rRNA sequences have not been detected in mats. A common feature of numerically relevant cyanobacterial, Chloroflexus-like and aerobic chemorganotrophic populations, is that they grow poorly and resist cultivation on solidified medium, suggesting plating bias, and that the medium composition and incubation conditions may not reflect the natural microenvironments these populations inhabit.

Non-NASA Center↗
NASA NTRS2019

Nasa GeneLab Computomics Reveal Horizontal Gene Transfer on International Space Station Environmental Metagenomes

Prokaryotic lifeforms can be observed to demonstrate many keen adaptive advantages, perhaps facilitated by a nature simplistic relative to divergent domains of life. In particular, decompartmentalized gene expression facilitates adaptation by allowing free exchange of genetic material, albeit at the cost of increased susceptibility to genetic damage. Thus, these lifeforms must compensate by embracing diverse investment strategies in an attempt to “brute force” the evolvability equation through precipitous genesis, lean metabolic efficiency, and sheer population. This prokaryotic archetype also enables symbiotic relationships with secondary mobile genetic elements known as plasmids, which have been shown to drive evolution on rapid temporal scales through processes such as conjugation and transformation. This study attempts to decipher whether these mechanisms of horizontal gene transfer (HGT) are major factors in determining prokaryote fitness within a unique isolated environment, the International Space Station (ISS). The ISS Microbial Tracking (MT) project has generated a wealth of data concerning the successive reigns of microbial genera that appear to thrive amidst harsh conditions for life. Despite relatively higher doses of ionizing radiation as compared to Earth, complications associated with microgravity, and the anti-microbial mélange deployed, microbial life still persists in this environment. The NASA GeneLab serves as a data repository and analysis platform to enable researchers to access space flight factor related data. With the use of GeneLab’s modern computational suites (computomics), phylogenetic and functional genomic investigations of HGT events were conducted on the data generated from the MT-1 project. The putative data concerning the plasmid population (plasmidome) of the ISS was algorithmically derived and compared to those of habitats with similar environmental dynamics- such as living quarters and hospitals- to investigate whether these HGT elements may play crucial role(s) in shaping the microbiome of this closed habitat that serves as the only inhabited structure in space.

Bense, Nicholas↗
NASA NTRS2006

Planned Environmental Microbiology Aspects of Future Lunar and Mars Missions

With the establishment of the Constellation Program, NASA has initiated efforts designed similar to the Apollo Program to return to the moon and subsequently travel to Mars. Early lunar sorties will take 4 crewmembers to the moon for 4 to 7 days. Later missions will increase in duration up to 6 months as a lunar habitat is constructed. These missions and vehicle designs are the forerunners of further missions destined for human exploration of Mars. Throughout the planning and design process, lessons learned from the International Space Station (ISS) and past programs will be implemented toward future exploration goals. The standards and requirements for these missions will vary depending on life support systems, mission duration, crew activities, and payloads. From a microbiological perspective, preventative measures will remain the primary techniques to mitigate microbial risk. Thus, most of the effort will focus on stringent preflight monitoring requirements and engineering controls designed into the vehicle, such as HEPA air filters. Due to volume constraints in the CEV, in-flight monitoring will be limited for short-duration missions to the measurement of biocide concentration for water potability. Once long-duration habitation begins on the lunar surface, a more extensive environmental monitoring plan will be initiated. However, limited in-flight volume constraints and the inability to return samples to Earth will increase the need for crew capabilities in determining the nature of contamination problems and method of remediation. In addition, limited shelf life of current monitoring hardware consumables and limited capabilities to dispose of biohazardous trash will drive flight hardware toward non-culture based methodologies, such as hardware that rapidly distinguishes biotic versus abiotic surface contamination. As missions progress to Mars, environmental systems will depend heavily on regeneration of air and water and biological waste remediation and regeneration systems, increasing the need for environmental monitoring. Almost complete crew autonomy will be needed for assessment and remediation of contamination problems. Cabin capacity will be limited; thus, current methods of microbial monitoring will be inadequate. Future methodology must limit consumables, and these consumables must have a shelf life of over three years. In summary, missions to the moon and Mars will require a practical design that prudently uses available resources to mitigate microbial risk to the crew.

Ott, C. Mark↗
NASA NTRS2011

Crop and Substrate Tests with Single Use Rooting "Pillows" for the VEGGIE Plant Growth Hardware

VEGGIE is a small plant production chamber built by ORBITEC. This chamber can be collapsed for easy stowage and deployed in orbit. It is designed for gravity independent operation, and provides 0.17 square m of crop growth area with three primary subsystems: an LED light panel, extendable transparent Teflon bellows to enclose the plants, and a wicking reservoir. VEGGIE would provide the capability for astronauts to grow fresh foods for dietary supplementation. Initial planting concepts tested with the VEGGIE included direct seeding or plug placement on the reservoir surface. These options had issues of salt accumulation and eventual toxicity if the reservoir was filled with nutrient solution, and hardware reuse was limited due to sanitation. In response a rooting packet or "pillow" concept was developed: single-use bags of media containing time release fertilizer with a wicking surface contacting the VEGGIE reservoir. Pillows being tested are small electrostatic bags with a Nitex nylon mesh side, each holding 100 mL of dry media. Six pillows fit in one VEGGIE unit; however pillow size could vary depending on crop selected. Seeds can be planted directly in pillows and planted pillows can be hydrated in space as desired. Our goals were to define optimal media and crops for an ISS mission scenario. Plant tests in pillows were performed in a controlled environment chamber set to habitat-relevant conditions, and capillary reservoir analogs were utilized. Media tested within pillows included: a commercial peat-based potting mix, arcillite (calcined clay), perlite: vermiculite, and peat-based: arcillite blends. Testing included 15 types of leafy greens, snow pea, radish, and herbs. Media performance was crop dependent, but generally plants showed the greatest growth in the peat-based: arcillite mixes. Crops with the best performance in pillows were identified, and testing is underway with select leafy greens examining plant and microbial load response to repeated harvest. We plan to use findings from previous flight testing with media to evaluate the effects of capillary flow from the reservoir to pillows in microgravity.

Massa, Gioia↗
DOE OSTI2026

Fostering Peat Moss Feedbacks to Accelerate Peatland Restoration

Extensive knowledge exists on plant-species traits and functions, but we understand less about how population- or community-level emergent traits influence ecosystem functioning. This knowledge gap is important for ecosystems like peatlands, arid drylands, salt marshes, seagrass meadows and mangroves, where emergent traits of plant communities can create plant-environment feedbacks that amplify or dampen ecosystem processes. Recent insights from restoration ecology suggest that these feedbacks can critically influence restoration success. Despite growing recognition of emergent trait-driven feedbacks in other ecosystems, they remain underexplored in peatland restoration, world’s most carbon-dense ecosystem. Here, we review emergent self-amplifying and self-dampening feedbacks with net positive effects for peat moss-dominated systems. We show how these feedbacks can promote key physical, chemical, and biological processes that enhance peat moss growth, increase water retention, and reduce microbial decomposition of organic matter. Understanding and fostering these feedbacks offers a promising framework to accelerate peatland restoration across diverse degradation states.

Sphagnum↗
DOE OSTI2025

Microbial ecology of acidic, biogenic gypsum: community structure and distribution of extremophiles on freshly formed and relict sulfate deposits in a hydrogen sulfide-rich cave

Sulfate minerals are abundant on the Martian surface, and many of these evaporite deposits are thought to have precipitated from acidic fluids. On Earth, gypsum (CaSO 4 •2H 2 O) and other sulfates sometimes form under acidic conditions, so exploring the extremophilic life that occurs in these mineral environments can help evaluate the astrobiological potential of acid sulfate depositional settings. Here, we characterized the microbial communities associated with acidic gypsum deposits in a sulfuric acid cave, where sulfate precipitation is driven by sulfide-oxidizing bacteria and archaea. We used 16S rRNA gene sequencing and cell counts to characterize gypsum-associated microorganisms in freshly formed and relict deposits throughout the cave, to test how microbial community composition and abundance would vary with distance from the sulfidic water table and with the concentration of H 2 S(g) and other gases in the cave atmosphere. We found that actively forming gypsum in the lower cave levels was colonized by low-diversity communities that have few cells compared to other environments in the cave. The most abundant taxa were Acidithiobacillus, Metallibacterium, Mycobacteria, and three different Thermoplasmatales-group archaea, which occupied distinct niches based on proximity to sulfidic streams and the concentration of gases in the cave air. By contrast, deposits in older cave levels had more diverse communities that were distinct from those associated with freshly formed gypsum and likely represent a community reliant on different energy resources. These findings show that acidic sulfate deposits serve as habitats for extremophilic microorganisms and broaden our knowledge of the life associated with terrestrial sulfates.

58 GEOSCIENCES↗
NASA NTRS2011

Research and Technology Development to Advance Environmental Monitoring, Food Systems, and Habitat Design for Exploration Beyond Low Earth Orbit

Exploration missions will carry crews far beyond the relatively safe environs of cis-lunar space. Such trips will have little or no opportunity for resupply or rapid aborts and will be of a duration that far exceeds our experience to date. The challenges this imposes on the requirements of systems that monitor the life support and provide food and shelter for the crew are the focus of much research within the Human Research Program. Making all of these technologies robust and reliable enough for multi-year missions with little or no ability to run for home calls for a thorough understanding of the risks and impacts of failure. The way we currently monitor for microbial contamination of water, air, and surfaces, by sampling and growing cultures on nutrient media, must be reconsidered for exploration missions which have limited capacity for consumables. Likewise, the shelf life of food must be increased so that the nutrients required to keep the crewmembers healthy do not degrade over the life of the mission. Improved formulations, preservation, packaging, and storage technologies are all being investigated for ways slow this process or replace stowed food with key food items grown fresh in situ. Ensuring that the mass and volume of a spacecraft are used to maximum efficiency calls for infusing human factors into the design from its inception to increase efficiency, improve performance, and retain robustness toward operational realities. Integrating the human system with the spacecraft systems is the focus of many lines of investigation.

Sullivan, Thomas A.↗
NASA NTRS2017

Space Plants for Astronaut Consumption

Growing plants in space will be an essential part of sustaining astronauts during long-range missions. During the summer of 2017, three female NASA interns, have been engaged in research relevant to food production in space, and will present their projects to an all female program known as Girls in STEM camp. Ayla Grandpre, a senior from Rocky Mountain College, has performed data mining and analysis of crop growth results gathered through Fairchild Botanical Gardens program, Growing Beyond Earth. Ninety plants were downselected to three for testing in controlled environment chambers at KSC. Ayla has also managed an experiment testing a modified hydroponics known as PONDS, to grow mizuna mustard greens and red robin cherry tomatoes. Emma Boehm, a senior from the University of Minnesota, has investigated methods to sterilize seeds and analyzed the most common microbial communities on seed surfaces. She has tested a bleach fuming method and an ethanol treatment. Emma has also tested Tokyo bekana Chinese cabbage seeds from four commercial seed vendors to identity differences in germination and growth variability. Lastly, Payton Barnwell, a junior from Florida Polytechnic University has shown that light recipes provided by LEDs can alter the growth and nutrition of 'Outredgeous' lettuce, Chinese cabbage, and Mizuna. The results of her light quality experiments will provide light recipe recommendations for space crops that grown in the Advanced Plant Habitat currently aboard the International Space Station.

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