Mechanistic insights on the responses of plant and ecosystem gas exchange to global environmental change: lessons from Biosphere 2

Scaling up leaf processes to canopy/ecosystem level fluxes is critical for examining feedbacks between vegetation and climate. Collectively, studies from Biosphere 2 Laboratory have provided important insight of leaf-to-ecosystem investigations of multiple environmental parameters that were not before possible in enclosed or field studies. B2L has been a testing lab for the applicability of new technologies such as spectral approaches to detect spatial and temporal changes in photosynthesis within canopies, or for the development of cavity ring-down isotope applications for ecosystem evapotranspiration. Short and long term changes in atmospheric CO2, drought or temperature allowed for intensive investigation of the interactions between photosynthesis and leaf, soil and ecosystem respiration. Experiments conducted in the rainforest biome have provided some of the most comprehensive dataset to date on the effects of climate change variables on tropical ecosystems. Results from these studies have been later corroborated in natural rainforest ecosystems and have improved the predictive capabilities of models that now show increased resilience of tropics to climate change. Studies of temperature and CO2 effects on ecosystem respiration and its leaf and soil components have helped reconsider the use of simple first-order kinetics for characterizing respiration in models. The B2L also provided opportunities to quantify the rhizosphere priming effect, or establish the relationships between net primary productivity, atmospheric CO2 and isoprene emissions.

Can plants grow on Mars and the moon: a growth experiment on Mars and moon soil simulants

When humans will settle on the moon or Mars they will have to eat there. Food may be flown in. An alternative could be to cultivate plants at the site itself, preferably in native soils. We report on the first large-scale controlled experiment to investigate the possibility of growing plants in Mars and moon soil simulants. The results show that plants are able to germinate and grow on both Martian and moon soil simulant for a period of 50 days without any addition of nutrients. Growth and flowering on Mars regolith simulant was much better than on moon regolith simulant and even slightly better than on our control nutrient poor river soil. Reflexed stonecrop (a wild plant); the crops tomato, wheat, and cress; and the green manure species field mustard performed particularly well. The latter three flowered, and cress and field mustard also produced seeds. Our results show that in principle it is possible to grow crops and other plant species in Martian and Lunar soil simulants. However, many questions remain about the simulants' water carrying capacity and other physical characteristics and also whether the simulants are representative of the real soils.

Climate and atmosphere simulator for experiments on ecological systems in changing environments

Grand challenges in global change research and environmental science raise the need for replicated experiments on ecosystems subjected to controlled changes in multiple environmental factors. We designed and developed the Ecolab as a variable climate and atmosphere simulator for multifactor experimentation on natural or artificial ecosystems. The Ecolab integrates atmosphere conditioning technology optimized for accuracy and reliability. The centerpiece is a highly contained, 13-m(3) chamber to host communities of aquatic and terrestrial species and control climate (temperature, humidity, rainfall, irradiance) and atmosphere conditions (O2 and CO2 concentrations). Temperature in the atmosphere and in the water or soil column can be controlled independently of each other. All climatic and atmospheric variables can be programmed to follow dynamical trajectories and simulate gradual as well as step changes. We demonstrate the Ecolab's capacity to simulate a broad range of atmospheric and climatic conditions, their diurnal and seasonal variations, and to support the growth of a model terrestrial plant in two contrasting climate scenarios. The adaptability of the Ecolab design makes it possible to study interactions between variable climate-atmosphere factors and biotic disturbances. Developed as an open-access, multichamber platform, this equipment is available to the international scientific community for exploring interactions and feedbacks between ecological and climate systems.

[Use of the ion-exchange substrate to optimize mineral nutrition of plants within a bio-engineering life support system with a high level of closure]

Purpose of the work was to test manageability of nutrient solutions containing mineralized human exometabolites by using an ion-exchange substrate (IES) for cultivating wheat in a bio-engineering life support system with a high level of closure. Object of the investigation was wheat Triticum aestivum L. (Lysovsky cv. l. 232). Crops were raised on clayite in a growth chamber of a hydroponic conveyor system under continuous light. Correction of nutrient solution was to lift the limits of crop supply with minerals. The experimental crop grew in nutrient solution with immersed IES "BIONA-312"; nutrient solution for the control crop was corrected by adding mineral salts. Solution correction did not have a noteworthy effect on the yield, CO2-gas exchange or mineral composition of wheat plants. IES makes simple the technology of plant cultivation on solutions enriched with human exometabolites.

[Promising technique of mineral supply organization for plants in the condition of microgravity]

The proposed system of automated nutrient solution preparation for plant cultivation in microgravity consists of an ion-exchange fabric artificial soil (AS) as a root-inhabited medium, a pack with slow release fertilizer as the main source of nitrogen, phosphorus and potassium and a cartridge with a granular mineral-rich ionite as a source of calcium, magnesium, sulphur and iron. Experiments proved that fabric AS BIONA-V3 is capable to stabilize pH of the substrate solution within the range of 6.0 to 6.6 favorable to the majority of vegetable cultures. The experimental data attested suitability of this technique of water forcing through mineral-containing packs to automate nutrient solution preparation for crops cultivated in space greenhouses, and to minimize the stock of fabric AS onboard the space vehicle.

[Development of paste-type food for experiments with mice onboard unmanned spacecrafts]

One of the crucial issues of handling animals in space flight is availability of food and water supply systems. However, water supply for animal experiments onboard unmanned spacecrafts is a particularly formidable problem. To maintain laboratory mice in space flight, a paste-type food was formulated on the basis of the standard extruded combined food for laboratory rodents (PK-120) with a 18.3% wet protein content and moisture raised to 68%. Food manufacturing technology for rodents reproduces essentially the one for quails that had shown good advantages in an experiment with adult birds aboard orbital complex Mir. The proposed food was tested with white laboratory mice (males and females) of mature 37-d age. According to the data of blood clinical analysis and visceral organs morphology investigations, feeding with the paste-type food without additional water over 21 days did not change the life weight of mice or food digestibility and availability. These biological test results gave go to feed mice in the Bion-M1 and synchronous ground experiments with the paste-type food.

[Interconnected operator's activity under the conditions of experimental climatic stress]

Homeostatic testing was used to monitor the interpersonal instrumental interaction of participants in the experiment with isolation in the conditions of abnormally high temperatures and pall of smoke. It was found that the factor of extreme exposure influenced the team work activity in the isolated small group. Homeostatic testing allowed differentiation between 2 types of people, i.e. leaders and subordinates, and identify those who combine traits of both the leader and subordinate. The data suggest that success of a common task is determined as by well-considered, purposive actions of the leader, so by spontaneous, on the pattern of random search, contribution from operators.

[Ion-exchange substrate as a source of nitrogen mobile forms in the conveyor method of vegetables cultivation on artificial soil]

The investigation had the objective to evaluate the applicability of ion-exchange substrate to maintaining the mobile nitrogen content in irrigation solution and artificial coil during cultivation of a mixed (in term of age) vegetable container. Objects of the investigation were radishes and leaf cabbage crops with the period of vegetation of 28 days. A 120-day experiment showed that single introduction of the ion-exchange substrate promoted nitrogen stabilization in the irrigation solution and, consequently, yielding of higher crops as compared with the control.

[Changes of organic soil substrate properties with different cultivation years and their effects on cucumber growth in solar greenhouse]

This paper studied the changes of organic soil substrate properties with increasing cultivation years and their effects on the cucumber growth in solar greenhouse. The results showed that with increasing cultivation years, the physical and chemical properties of organic soil substrate deteriorated, which was manifested in the increase of bulk density and the decrease of total porosity, pH, and available nutrient contents. The numbers of bacteria and actinomycetes in the substrate decreased with increasing cultivation years, while that of fungi was in reverse. The cucumber growth was also affected to a certain extent, manifesting in the decrease of plant height and leaf area, the decline of photosynthetic efficiency, and the decrease of yield and quality. It would be necessary to restore the fertility of organic soil substrate after 3-year cultivation.

[Development of a minerals supply system for plants in a conveyor-type space greenhouse]

The paper presents ideas of optimizing the mineral nutrition system for salad crops in a space greenhouse. Experiments showed that to use mineral-saturated fiber ionite BIONA-V3 as an artificial soil will require to upmass a lot of expandable materials because of low specific content of nutrients. An additionally mineralized fiber soil makes possible to reduce mass of ionite in 5.6 times and volume in 28 times. The proposed mineral supply system is composed of two enrichment catridges with granulated ionite BIONA-V3 and slow-releasing fertilizer Osmocote 114-14-4, and a controller of irrigation water electric conduction stabilizer. Tests showed that this system provides sufficient mineral nutrition to plants and can be recommended for in-flight testing.

[Estimation model for daily transpiration of greenhouse muskmelon in its vegetative growth period]

For developing an estimation method of muskmelon transpiration in greenhouse, an estimation model for the daily transpiration of greenhouse muskmelon in its vegetative growth period was established, based on the greenhouse environmental parameters, muskmelon growth and development parameters, and soil moisture parameters. According to the specific environment in greenhouse, the item of aerodynamics in Penman-Monteith equation was modified, and the greenhouse environmental sub-model suitable for calculating the reference crop evapotranspiration in greenhouse was deduced. The crop factor sub-model was established with the leaf area index as independent variable, and the form of the model was linear function. The soil moisture sub-model was established with the soil relative effective moisture content as independent variable, and the form of the model was logarithmic function. With interval sowing, the model parameters were estimated and analyzed, according to the measurement data of different sowing dates in a year. The prediction accuracy of the model for sufficient irrigation and water-saving irrigation was verified, according to measurement data when the relative soil moisture content was 80%, 70%, and 60%, and the mean relative error was 11.5%, 16.2% , and 16.9% respectively. The model was a beneficial exploration for the application of Penman-Monteith equation under greenhouse environment and water-saving irrigation, having good application foreground and popularization value.

Combining principles of Cognitive Load Theory and diagnostic error analysis for designing job aids: Effects on motivation and diagnostic performance in a process control task

Two studies are presented in which the design of a procedural aid and the impact of an additional decision aid for process control were assessed. In Study 1, a procedural aid was developed that avoids imposing unnecessary extraneous cognitive load on novices when controlling a complex technical system. This newly designed procedural aid positively affected germane load, attention, satisfaction, motivation, knowledge acquisition and diagnostic speed for novel faults. In Study 2, the effect of a decision aid for use before the procedural aid was investigated, which was developed based on an analysis of diagnostic errors committed in Study 1. Results showed that novices were able to diagnose both novel faults and practised faults, and were even faster at diagnosing novel faults. This research contributes to the question of how to optimally support novices in dealing with technical faults in process control.

[Status of the water-soluble component of the antioxidant defense system in the conditions of 520-day isolation]

In the 520-d chamber experiment within the international project Mars-500 blood samples of 6 male test-subjects of 28 to 39 years of age were analyzed for water-soluble antioxidants: total bilirubin and uric acid; in addition, total antioxidant capacity of blood plasma was determined. Maximal values of these parameters were associated with the most stressful periods of the experiment, i.e. adaptation to the life in isolation and confinement, simulation of the egress onto Martian surface, and change of the diet. On attainment of the homeostatic equilibrium the parameters stabilized on levels slightly lower relative to baseline (pre-isolation) values. Therefore, dynamics of the water-soluble antioxidants reflected adequately the homeostatic reactions to and compensation by organism of the effects of the 520-day life in isolation and confinement.

[Gaseous content regeneration system]

The article presents a possible design of an atmosphere revitalization system (ARS) as a component part of a new generation life support system (LSS). The main goal of the test investigation was to block formation of solid hard-to-remove carbon as a by-product of carbon dioxide and hydrogen processing. The Bosch reaction stage of CO2 conversion into CO and water was chosen as the core one. Beside the C02 and hydrogen conversion unit, other ARS constituents are a palladium membrane to generate ultrapure hydrogen, a water electrolysis unit, a hydrogen accumulator and a hydrogen absorber. To reach the materials balance, ARS was complemented with a system for trace contaminants and CO2 removal, and a Co2 concentrator. Zeolites in the CO2 removal system and concentrator ensure microwave energy absorption. Hydrogen is accumulated and absorbed by a LaNi5-based intermetallide. The palladium membrane serves to separate hydrogen from the CO-CO2 mixture.

Ion-specific nutrient management in closed systems: the necessity for ion-selective sensors in terrestrial and space-based agriculture and water management systems

The ability to monitor and control plant nutrient ions in fertigation solutions, on an ion-specific basis, is critical to the future of controlled environment agriculture crop production, be it in traditional terrestrial settings (e.g., greenhouse crop production) or as a component of bioregenerative life support systems for long duration space exploration. Several technologies are currently available that can provide the required measurement of ion-specific activities in solution. The greenhouse sector has invested in research examining the potential of a number of these technologies to meet the industry's demanding requirements, and although no ideal solution yet exists for on-line measurement, growers do utilize technologies such as high-performance liquid chromatography to provide off-line measurements. An analogous situation exists on the International Space Station where, technological solutions are sought, but currently on-orbit water quality monitoring is considerably restricted. This paper examines the specific advantages that on-line ion-selective sensors could provide to plant production systems both terrestrially and when utilized in space-based biological life support systems and how similar technologies could be applied to nominal on-orbit water quality monitoring. A historical development and technical review of the various ion-selective monitoring technologies is provided.

[Results of salad machine experiment within the MARS-500 project]

The salad machine experiment was aimed to fulfill performance testing of a prototype of space conveyor-type cylindrical greenhouse PHYTOCYCLE-SL, to study growth and development of plants, and to evaluate microbial contamination of equipment in the closed manned environment. Crops of leaf cabbage Brassica chinensis L., cultivar Vesnianka were raised in the time interval between MARS-500 days 417 and 515. The greenhouse proved it serviceability demanding 17 min/(man x d) in the normal mode. Most likely that the slow growth rate and deviations in plant morphology were caused by the presence of volatile pollutants in the greenhouse compartment Accumulation of micromycetes was observed at the sites of humid surfaces contact with ambient air; reduction of the artificial soil area contacting with air decreased population of micromycetes in 40 times. Cabbage leafs were free of pathogenic microflora. These results of the experiment helped develop recommendations on how to work out some units and systems in projectable greenhouse VITACYCLE-T

Space plant biology research in Lithuania

In 1957, the Soviet Union launched the first artificial Earth satellite, initiating its space exploration programs. Throughout the rest of the twentieth century, the development of these space programs received special attention from Soviet Union authorities. Scientists from the former Soviet Republics, including Lithuania, participated in these programs. From 1971 to 1990, Lithuanians designed more than 20 experiments on higher plant species during space flight. Some of these experiments had never before been attempted and, therefore, made scientific history. However, the formation and development of space plant biology research in Lithuania or its origins, context of formation, and placement in a worldwide context have not been explored from a historical standpoint. By investigating these topics, this paper seeks to construct an image of the development of a very specific field of science in a small former Soviet republic.

[Computer modeling of electrodynamic processes in SHF-based water disinfection and heating system as part of the spacecrew life support system]

To optimize the design of SHF-based potable water disinfection and heating subsystem within the life support system (LSS), computer modeling of the super-high frequency electromagnetic field in SHF-based waveguide-coaxial and coaxial running water heaters was performed Software package CST Microwave Studio 2010 was used as the main instrument in the investigation. Results of the investigation can contribute to the development and prototyping of an HSF-based water heater as an integral part of advanced life support system for spacecrews

[Calcium and phosphorus content of human organism during 105-day isolation]

Total and ultrafiltered calcium, total and inorganic phosphorus in blood serum and diurnal secretion of calcium and phosphorus with urine were determined before (baseline data collection) and on days 30, 60 and 105 of human subjects' isolation. Calcium and phosphorus content in hair was determined during BDC and on day 105 of the experiment. The measurements were fulfilled with the help of inductively coupled plasma atomic emission spectrometry. Levels of total and ultrafiltered calcium, total and inorganic phosphorus as well as urine calcium and phosphorus in daily urine and hair varied within admissible physiological ranges unfailingly at all the times of investigation. Shifts in the serum calcium and phosphorus balance occur at the expense of their physiologically active forms representing an immediate reaction to the experimental conditions. Calcium and phosphorus levels deviated from baseline values after 30 days of isolation and demonstrated stability till day 105.

[Analysis of protein ratios based on the studies of human urine proteome in an experiment with 105-day isolation]

Purpose of the work was to study urine proteome of healthy human subjects during 105-day isolation in controlled environment of the IBMP chamber with a self-sustained life support system. The parameters under study were diurnal rhythm, physical activity, water intake, as well as consumption of sodium, protein and some other basic nutrients. Urine was sampled by 6 male subjects at the age of 25 to 40 years admitted to the experiment by the medical certification commission. The studies were performed with the use of proteome data acquisition technologies; the cutting-edge bio-information analysis techniques including reconstruction of associative gene networks were applied to investigate the urine proteome profile, to structure experimental data in light of the existing physiological concepts and to formulate viable hypotheses for ensuing experimental verification. Proteins of different origin were identified in urine; appearance or disappearance of proteins was in tight correlation with salt consumption.

Ethylene reduces plant gas exchange and growth of lettuce grown from seed to harvest under hypobaric and ambient total pressure

Naturally occurring high levels of ethylene can be a problem in spaceflight and controlled environment agriculture (CEA) leading to sterility and irregular plant growth. There are engineering and safety advantages of growing plants under hypobaria (low pressure) for space habitation. The goals of this research were to successfully grow lettuce (Lactuca sativa cv. Buttercrunch) in a long-term study from seed to harvest under hypobaric conditions, and to investigate how endogenously produced ethylene affects gas exchange and plant growth from seed germination to harvest under hypobaric and ambient total pressure conditions. Lettuce was grown under two levels of total gas pressure [hypobaric or ambient (25 or 101 kPa)] in a long-term, 32-day study. Significant levels of endogenous ethylene occurred by day-15 causing reductions in photosynthesis, dark-period respiration, and a subsequent decrease in plant growth. Hypobaria did not mitigate the adverse ethylene effects on plant growth. Seed germination was not adversely affected by hypobaria, but was reduced by hypoxia (6 kPa pO(2)). Under hypoxia, seed germination was higher under hypobaria than ambient total pressure. This research shows that lettuce can be grown from seed to harvest under hypobaria (≅25% of normal earth ambient total pressure).

[Microbial fuel cells as an alternative power supply]

Purpose of the work was designing and prototyping of microbial fuel cells (MFC) and comparative evaluation of the electrogenic activity of wastewater autochthonous microorganisms as well as bacterial monocultures. Objects were model electrogenic strain Shewanella oneidensis MR-1, and an Ochrobactrum sp. strain isolated from the active anode biofilm of MFC composed as an electricity generating system. The study employed the methods typically used for aerobic and anaerobic strains, current measurement, identification of new electrogenic strains in microbial association of wastewater sludge and species definition by rRNA 16-S. As a result, two MFCs prototypes were tried out. Besides, it was shown that electrogenic activity of S. oneidensis MR-1 and Ochrobactrum sp. monocultures is similar but differs from that of the microbial association of the anode biofilm.

[Methods of extending the resource of fiber ionite artificial soils in space greenhouses]

The vegetable cultivation technology developed in view of long-term autonomous missions is based on root nutrition provided by fiber artificial soils (AS) containing ion-exchange resins. Useful life of ASs is limited by two factors which are nutrients depletion in ion-exchanger and clogging of the AS threshold space by roots remnants. Purpose of the investigation is to try out hydrolysis and ensuing microbial decomposition of roots remnants as a way to extend the resource of used fiber ionite AS. This principle of doing away with the roots remnants recovers almost completely the maximal water-absorbing capacity of AS BIONA-V3 so that it can be used again for crops cultivation.