The adaptation of life to extreme conditions
Until rather recently we believed that life was essentially subtle and could only develop in environments similar to the ones that warm-blooded animals require (temperatures around 30ºC, pressure of one atmosphere, neutral pH, an ionic force similar to blood serum). The discovery of extremophiles, thus, organisms capable of developing in very atypical conditions (high temperature: 113ºC; low temperatures: -30ºC; low ionic force: absence of ions; high ionic force: 5M NaCl; low pH: 0; high pH: 12; high dosis of radiation; low pressure: 10-6 mb; elevated pressure: 1000 Mp; etc.,), has had very important implications in different fields of science in general, and of astrobiology in particular.
In this conference we will focus on the different habitats in which our protagonists, the extremophiles, develop with the aim of becoming familiarized with the levels of difficulty that the development of life has in each of them (the integrity of the membrane, the denaturalization of proteins and nucleic acids, osmotic pressure, speed of reaction, etc.), and this way, address the strategies applied by each of these organisms to counter the negative effects that an extreme condition or a sum of extreme conditions can pose.
Finally, we will focus on the study of microbial ecology in the Tinto river with aim of getting familiarized with the type of work that research on the ecology of extreme environments implies. The Tinto is an acid river (average pH 2.3) of more that 100 km of length that is originated by the metabolic activity of microorganisms capable of of growing by using metallic sulfurs as a source of energy, fundamentally pyrite, which exists in elevated concentrations in the Iberian Pyrite Belt. We will become familiarized with the mechanisms involved in the obtention of energy in strict chemolithoautotrophic microorganisms that develop in this environment, review the conventional techniques applied in microbial ecology and molecular ecology that are being used to explore this peculiar environment, analyze the data obtained to create a running model of the system, analyze some of the mineral byproducts produced by the microorganisms (goethite, jarosite , hematine, etc.), and their use for dating the age of the river. We will also see the mineralogical convergence between this environment produced by living beings in the Tinto river and the analogue case of Mars as described by the NASA MERs, and the perforation results in the Pyrite Belt (project MARTE). All of this, from an astrobiological perspective that will allow us to answer the fundamental questions about if life in our blue planet is just a matter of chance, or if it is the product from the evolution of the universe, implying that it may have also taken place in other planetary systems. Finally, the teachings from the acidophile organisms of Tinto river will be compared to other extreme models that have been generated so far.