Microbial Ecology of Isolated Life Support Systems

Abstract

Microorganisms are the most widely spread form of living matter – occurring in every climatic region and in every zone of water and soil strata. They have a profound role in biogeochemical processes and are crucial for the completion of all biologically important material cycles, which support all life on Earth. Microorganisms can enter into varying interactions with human population – from “positive” forms of symbiosis, known as mutualism, to “negative” manifestations of parasitism, as in lethal generalized infections. Phenotypic adaptations, spontaneous mutations, and the action of natural selection regularly occur in microbial populations and microbial associations. Microorganisms have a significant role to play in all types of systems, which include humans. This is particularly so for enclosed habitats, where they need to be managed, as they are potentially the most hazardous component in the ecosystem. Characteristics, such as their great number, diversity of species, short life cycle, and ability to adapt rapidly to changes in environmental conditions give microorganisms inside the environment and those associated with the higher organisms themselves (humans, animals and plants), the potential to change a healthy system to a state of imbalance and hazard. Microflora can be introduced into a system deliberately to perform functions like photosynthesis, bioregeneration, and the controlled oxidation of organic matter. Such microflora need to be monitored and managed. The conditions to which microfloras are exposed in the closed habitat can differ markedly from those found in nature. In these cases, relationships between humans and internal bodily microfloras, between humans and the microfloras of the enclosure, and the exchange of microfloras between members of the crew become significant vectors. Spacecraft and space stations (orbital vehicles or habitats, Mars or Moon stations) operating for prolonged periods, as well as submarines representing a kind of simulated environment with similarities to the natural environment maintained artificially, can be considered as “testbeds” for research on microecological dynamics, function and risk. All materials discussed in the chapter prove that microbial populations and communities are the most active links of every type of closed ecosystems designed for Earth or Space needs. The problems of macro and microorganisms coexistence in different types of LSS, including Biosphere, are regularly discussed at different international conferences, especially COSPAR Scientific Assemblies and are important for environmental engineering design of different ecosystems.