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Tesia Irwin

Publications and source records attributed to Tesia Irwin.

14 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

Substrate Matters: Ionic Silver Alters Lettuce Growth, Nutrient Uptake, and Root Microbiome in a Hydroponics System

Ionic silver (Ag+) is being investigated as a residual biocide for use in NASA spacecraft potable water systems on future crewed missions. This water will be used to irrigate future spaceflight crop production systems. We have evaluated the impact of three concentrations (31 ppb, 125 ppb, and 500 ppb) of ionic silver biocide solutions on lettuce in an arcillite (calcinated clay particle substrate) and hydroponic (substrate-less) growth setup after 28 days. Lettuce plant growth was reduced in the hydroponic samples treated with 31 ppb silver and severely stunted for samples treated at 125 ppb and 500 ppb silver. No growth defects were observed in arcillite-grown lettuce. Silver was detectable in the hydroponic-grown lettuce leaves at each concentration but was not detected in the arcillite-grown lettuce leaves. Specifically, when 125 ppb silver water was applied to a hydroponics tray, Ag+ was detected at an average amount of 7 μg/g (dry weight) in lettuce leaves. The increase in Ag+ corresponded with a decrease in several essential elements in the lettuce tissue (Ca, K, P, S). In the arcillite growth setup, silver did not impact the plant root zone microbiome in terms of alpha diversity and relative abundance between treatments and control. However, with increasing silver concentration, the alpha diversity increased in lettuce root samples and in the water from the hydroponics tray samples. The genera in the hydroponic root and water samples were similar across the silver concentrations but displayed different relative abundances. This suggests that ionic silver was acting as a selective pressure for the microbes that colonize the hydroponic water. The surviving microbes likely utilized exudates from the stunted plant roots as a carbon source. Analysis of the root-associated microbiomes in response to silver showed enrichment of metagenomic pathways associated with alternate carbon source utilization, fatty-acid synthesis, and the ppGpp (guanosine 3′-diphosphate 5′-diphosphate) stringent response global regulatory system that operates under conditions of environmental stress. Nutrient solutions containing Ag+ in concentrations greater than 31 ppb in hydroponic systems lacking cation-exchange capacity can severely impact crop production due to stunting of plant growth.

lettuce↗
NASA NTRS2024

Lunar Soil Enrichment for Plant Production: WILD (Waste Improved Lunar Dirt)

To identify a process to generate a fertile soil for plant growth using lunar regolith and waste compost, several qualitative and quantitative investigations were performed. The primary focus of this project was to demonstrate the feasibility of microbe bioleaching to extract inorganic plant nutrients (P and K) from lunar regolith simulant. This was achieved by developing a screening test method to identify microbial candidates that would effectively bioleach P and K from JSC-1A. Quantitative bioleaching test using the downselected microbes (Pantoea Agglomerans (P. agglo) and a plant-relevant consortium) were then performed. The second focus of the project was to validate the approach of waste compost utilization to improve water retention and fertility of lunar regolith for food production. This was achieved by measuring the water retention property of the mixture of compost and regolith at different ratio and conducting microgreen growth experiments with compost/regolith mixtures. The team also discovered from this study that some native microbes associated with JSC-1A can form biofilm containing JSC-1A particles (a type of soil crust), which showed potential as an ISRU geomicrobiological dust mitigation method for Lunar or Martian applications.

Ray Pitts↗
NASA NTRS2024

Effects of Residual Water System Silver on Space Crop Microbiome and Nutrient Content

Ionic silver (Ag+) is being investigated as a residual biocide for use in spacecraft potable water systems on future crewed missions. In addition to providing clean water to the crew and other life support system functions, the potable water is used to irrigate space crop production units such as the Vegetable Production System (Veggie) and the Advanced Plant Habitat (APH). We have evaluated the impact of different concentrations of Ag+ biocide solutions in comparison to a control in both substrate (arcillite-based) and substrate-less (hydroponics-based) growth set ups. Here, we provide evidence that increasing the concentration of silver in the irrigation water impacts the root zone microbiome in both setups, with plant growth and elemental nutrient content also affected in the hydroponic set up. This suggests a need for a silver removal step to achieve acceptable silver levels in irrigation water before application to space crops in a substrate-less hydroponics system. This removal step is also recommended for a substrate-based system, although it is not as critical as in a hydroponics system.

Aubrie O’Rourke↗
NASA NTRSDate not supplied

Literature Review of Disinfection Techniques For Water Treatment

Water treatment is a developing concern, both terrestrially and in spacecraft, as exploration missions extend in time and distance. Current biofilm control is limited for long-term applications. To optimize biocides for present and future space exploration vehicles, a thorough understanding of common and traditional disinfectant techniques is required. This review is focused on the three fundamental disinfection techniques: chemical, physical, and biological. Mechanisms, advantages, disadvantages, and specific properties of each major technique, as well as their studied effect on established biofilms, are also considered. This paper provides a general background on disinfectants and some information on effects on biofilms that can be useful to develop innovative ideas for state-of-the-art disinfection techniques for water treatment in specific environments, such as those currently posing mission risks as well as for future spacecraft water system development.

Nilab Azim↗
NASA NTRSDate not supplied

A Preliminary Modeling Study of Biofilm Accumulation in the Water Recovery System

Bacterial biofilms are ubiquitous in wastewater systems on earth and in spacecraft, such as in the International Space Station (ISS) wastewater processing assembly (WPA), where they cause problems in the tank, solenoid valves, and pipelines. Downstream filter applications, tank cycling, and regular biocide water flushing have been used to control biofilm accumulation on board the ISS. Biofilm control is expected to be a challenge for long-term missions with a dormancy period of up to a year, as stagnant water systems are highly susceptible to biofilm growth. Flushing of the system with biocidal water has been proposed to avoid biomass problems for long-term missions. To validate the proposed flush method, a mathematical model, based on the metabolism maintenance rate of bacteria, is being developed to understand the current biofilm accumulation rate in the ISS WPA system and to calculate the biomass production rate under dormancy-like conditions. This method of quantification of biofilm can be applied as a function of nutrient inputs to guide the selection and optimization of biofilm mitigation approaches. The method can also be helpful in understanding, defining, quantifying, visualizing, and simulating the state of the water processing system during operation and after dormancy.

Angie M Diaz↗
NASA NTRSDate not supplied

Investigation into Space Effects on Biofilm Growth Using Simulated Microgravity

Bacterial growth in liquid media while under microgravity conditions is not well understood. Trends such as a shortened lag phase, longer log phase, slower growth rate, and a higher final population concentration have been noted but the underlying cause remains unclear. Ground-based spaceflight analogs, or simulated microgravity devices, are often employed to achieve different attributes of weightlessness to study effects on bacterial growth. Though these technologies could isolate gravity’s role in various biological processes, they cannot replicate all its effects and underlying mechanisms. Hence, results could be misleading even if they are similar to spaceflight. At the single cell level, it is predicted that bacteria are less gravity-sensitive than larger species. The effects on their immediate environment, including the cell settlement and slower mass transfer of nutrients, might help explain the trends seen in liquid media microgravity studies. Therefore, experimental design factors must be carefully considered when selecting a simulated microgravity device for proper underlying mechanisms and interpretation of results. To verify if the simulated microgravity devices simulate the relevant microgravity conditions for bacterial growth, including the changes in cell settlement and mass transfer of nutrients, a high aspect ratio vessel (HARV) was used with dyes of different density in various simulated microgravity setups. The results will help inform the selection of the proper simulated microgravity device as well as interpretation of subsequent biofilm growth results.

Angie M. Diaz↗
NASA NTRSDate not supplied

Microgravity Effect on Bacterial Growth: A Literature Review

Gravity is a well-known, but little understood, physical force. It interacts with other physical environmental factors to impact the formation of today’s Earth, and to contribute to biological variations between water and land species. It is also involved with cell differentiation process, and is responsible for setting the boundaries for life and keeping cells small. With their simple structures and small sizes, microbes are expected to be less gravity sensitive than larger species. Nevertheless, various effects of spaceflight on bacterial growth have been reported, but the reports have been sometime inconsistent, and the underlying mechanism remains unclear to many. This paper summarizes the systematic efforts to evaluate the spaceflight effect on microbial growth, highlighting the extracellular mass transfer mechanism. It also provides a critical literature review on the topic to resolve the discrepancy in experimental observations and to further clarify the underlying mechanisms.

Wenyan Li↗
NASA NTRSDate not supplied

Investigation into Stimulated Microgravity Techniques used to Study Biofilm Growth

Bacterial growth in liquid media in microgravity conditions is not well understood. Trends such as a shortened lag phase, longer log phase, slower growth rate, and a higher final population concentration have been noted but the underlying cause remains unclear. At the single cell level, it is predicted that bacteria are less gravity-sensitive than larger species. The effects on their immediate environment, including the lack of cell settlement and slower mass transfer of nutrients due to lack of density driven convection, could help explain the trends. Ground-based spaceflight analogs, or simulated microgravity devices, are often employed to achieve different attributes of weightlessness to study effects on bacterial growth. Though these technologies could isolate gravity’s role in various biological processes, they cannot replicate all its effects and underlying mechanisms. Hence, interpretation of results could be misleading, even if similar to spaceflight. In this study two common simulated microgravity devices were investigated to determine whether they could simulate relevant microgravity conditions for bacterial growth. A bioreactor, the high aspect ratio vessel (HARV), was used with dyes of different density mounted on a random positioning machine (RP machine) or a rotating wall vessel (RWV). The RP machine displayed higher mixing rates than the RWV. The RWV was further tested at different rotations per minute (RPM). The range to minimize effects of density driven convection (low speeds) or centrifugal forces (high speeds) was between a range of 15-20 RPM. These results will help inform the selection of simulated microgravity device as well as interpretation of subsequent biofilm growth results.

Angie M. Diaz↗
NASA NTRSDate not supplied

More Than a Decade of International Space Station Microbial Sampling in the Environmental Control and Life Support Systems

Microbial monitoring has taken place in major units belonging to the Environmental Control and Life Support Systems (ECLSS) of the International Space Station (ISS). For at least a decade multiple modules including US and RU segments were sampled. In the US ECLSS, water reclamation and air systems combine their microbial contents downstream where biofilm incidents have been recorded. Understanding the microbial contents of segments provides a longitudinal perspective to microbiome changes in the system that contribute to this issue. The US ECLSS have been consistently sampled, especially in the Potable Water Bus (PWB) where bacteria from upstream sources have been observed.

Yo-Ann Velez Justiniano↗
NASA NTRSDate not supplied

More Than a Decade of International Space Station Microbial Sampling in the Environmental Control and Life Support Systems

Microbial monitoring has taken place in major units belonging to the Environmental Control and Life Support Systems (ECLSS) of the International Space Station (ISS). For at least a decade multiple modules including US and RU segments were sampled. In the US ECLSS, water reclamation and air systems combine their microbial contents downstream where biofilm incidents have been recorded. Understanding the microbial contents of segments provides a longitudinal perspective to microbiome changes in the system that contribute to this issue. The US ECLSS have been consistently sampled, especially in the Potable Water Bus (PWB) where bacteria from upstream sources have been observed.

Yo-Ann Velez Justiniano↗
NASA NTRSDate not supplied

TOC Calibration Method for Exploration Application

Total organic carbon (TOC) is the amount of carbon associated with organic compounds in solution and is often used as a non-specific indicator for water quality or cleanness. Currently, the Total Organic Carbon Analyzer (TOCA) is being used onboard the International Space Station (ISS) for water recovery system process control. An exploration-class TOCA is now being developed to close the technology gaps between the State-of-the-Art ISS TOCA and the emerging requirements of future exploration missions. One of the technical gaps for an exploration TOC analyzer is the development of suitable methods for on-orbit calibration. While the ISS TOCA uses pre-packaged ground-supplied TOC calibration standards, there is limited stability data. Other options include preparing calibration standards in space, which can be challenging due to the lack of low TOC reagent water. This paper explores the practice of the standard addition method and passive dosing approaches as potential solutions to overcome this problem.

Wenyan Li↗