15 items with the tag “nitrogen

  • Stoichiometry of Life, Task 2b: Field Studies - Cuatro Cienegas
    NAI 2009 Arizona State University Annual Report

    Cuatro Cienegas is a unique biological preserve in which there is striking microbial diversity, potentially related to extreme scarcity of phosphorus. We aim to understand this relationship.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2
  • Stoichiometry of Life, Task 1: Laboratory Studies in Biological Stoichiometry
    NAI 2009 Arizona State University Annual Report

    Living things require a broad menu of chemical elements to function. This project aims to quantify the chemical elements required by prokaryotes – the class of terrestrial organisms thought most similar to those that might be present in extraterrestrial settings – through laboratory experiments. These experiments will also teach us the ways in which such organisms cope with scarcity of the bioessential elements nitrogen, phosphorus and iron. We are also conducting experiments to isolate micro-organisms that use the element arsenic in place of phosphorus, if they exist. In Year 1 we initiated the first stage of these experiments.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2 7.1
  • Project 6: The Environment of the Early Earth
    NAI 2009 Rensselaer Polytechnic Institute Annual Report

    Our project entitled “Environment of the Early Earth” involves the development of capabilities that will allow scientists to obtain information about the conditions on early Earth (3.0 to 4.5 billion years ago) by performing chemical analyses of crystals (minerals) that have survived since that time. When they grow, minerals incorporate trace concentrations of ions and gaseous molecules from the local environment. We are conducting experiments to calibrate the uptake of these “impurities” that we hope will serve as indicators of temperature, moisture, oxidation state and atmosphere composition. To date, our focus has been mainly on zircon (ZrSiO4), but we have recently turned our attention to quartz as well.

    ROADMAP OBJECTIVES: 1.1 4.1 4.3
  • Stoichiometry of Life - Task 1f - Concept Studies - Nickel-Molybdenum Co-Limitation and Evolution of Mo-Nitrogenase
    NAI 2010 Arizona State University Annual Report

    The element molybdenum (Mo) is critical for key processes in the cycling of nitrogen (N); for example, it is essential for the enzyme nitrogenase which bacteria use to convert gaseous N to “fixed” N that can be used in biological processes. However, this process costs a lot of energy. In some microbes, this energy can be captured and used via enzymes that involve both Mo and nickel (Ni). This project investigates the role of these Ni-Fe enzymes in making nitrogenase-driven processes more energetically efficient and how these enzymes may have evolved in the deep past when Ni concentrations were lower.

    ROADMAP OBJECTIVES: 4.1 5.1 5.2 6.1
  • Stoichiometry of Life - Task 1e- Experimental Studies - Diatom Growth on Iron Nanoparticles
    NAI 2010 Arizona State University Annual Report

    In some environments (such as ocean regions fed by icebergs), the critical element iron (Fe) is supplied in the form of very small (“nano”) particles that are suspended rather than dissolved in water. However, it’s not known if this nanoparticle Fe is available to microscopic phytoplankton. This project involves experiments testing whether diatoms (a key oceanic phytoplankton group) can access nanoparticle Fe.

    ROADMAP OBJECTIVES: 6.1
  • Stoichiometry of Life - Task 1d - Experimental Studies - the Role of Molybdenum in the Nitrogen Cycle, Past and Present
    NAI 2010 Arizona State University Annual Report

    The element molybdenum (Mo) is critical for key processes in the cycling of nitrogen (N); for example, it is essential for the enzyme nitrogenase which bacteria use to convert gaseous N to “fixed” N that can be used in biological processes. This project seeks to understand how Mo might limit N processing in modern ecosystems (lakes and oceans) and infer its potential role in the past.

    ROADMAP OBJECTIVES: 4.1 5.1 6.1
  • Stoichiometry of Life, Task 2b: Field Studies - Cuatro Cienegas
    NAI 2010 Arizona State University Annual Report

    Cuatro Cienegas is a unique biological preserve in which there is striking microbial diversity, potentially related to extreme scarcity of phosphorus. We aim to understand this relationship via field sampling of biological and chemical characteristics and a series of enclosure and whole-pond fertilization experiments.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2
  • Stoichiometry of Life, Task 1a: Experimental Studies - Cellular Stoichiometry Under Nutrient Limitation in Chemostats
    NAI 2010 Arizona State University Annual Report

    In this project we are raising several species of “extremophile” microbes at different growth rates under different kinds of element limitation (N, P, and Fe) in order to determine how their “elemental recipes” (in terms of C, N, P, Fe, and other metals) change with environmental conditions. These data will help us understand similar data to be obtained from microbes in natural ecosystems.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2 7.1
  • Project 6: The Environment of the Early Earth
    NAI 2010 Rensselaer Polytechnic Institute Annual Report

    This project involves the development of capabilities that will allow scientists to obtain information about the conditions on early Earth (3.0 to 4.5 billion years ago) by performing chemical analyzes of crystals (minerals) that have survived since that time. When they grow, minerals incorporate trace concentrations of ions and gaseous molecules from the local environment. We are conducting experiments to calibrate the uptake of these “impurities” that we expect to serve as indicators of temperature, moisture, oxidation state and atmosphere composition. To date, our focus has been mainly on zircon (ZrSiO4), but we have recently turned our attention to quartz as well.

    ROADMAP OBJECTIVES: 1.1 4.1 4.3
  • Evolution of Metabolism
    NAI 2011 VPL at University of Washington Annual Report

    Our astrobiology research focus for VPL is to understand the evolution of different metabolic groups of microorganisms during the course of Earth’s history, and how the emergence of different metabolisms, such as methanogenesis, anoxic and oxygenic photosynthesis, and other anaerobic metabolisms that involve sulfur, metal, and nitrogen could effect the chemical composition of the atmosphere.

    ROADMAP OBJECTIVES: 5.1 5.3 6.2
  • Stoichiometry of Life - Task 1 - Laboratory Studies in Biological Stoichiometry
    NAI 2011 Arizona State University Annual Report

    This project component involves a diverse set of studies of various microorganisms with which we are trying to better understand how living things use chemical elements (nitrogen, phosphorus, iron, etc) and how they cope, in a physiological sense, with shortages of such elements. For example, how does the “elemental recipe of life” change when an organism is starved for phosphorus? Is this change similar for diverse species of microorganisms? Are the changes the same if the organism is limited by a different key nutrient? Furthermore, how does an organism shift its patterns of gene expression when it is starved by various nutrients? This will help in interpreting studies of gene expression in natural environments. At an even more profound level: can an organism substitute an element that is similar to the one that is limiting, as in the case of arsenic for phosphorus?

    ROADMAP OBJECTIVES: 5.2 5.3 6.1 6.2
  • Project 6: The Environment of the Early Earth
    NAI 2011 Rensselaer Polytechnic Institute Annual Report

    This project involves the development of capabilities that will allow scientists to obtain information about the conditions on early Earth (3.0 to 4.5 billion years ago) by performing chemical analyzes of crystals (minerals) that have survived since that time. When they grow, minerals incorporate trace concentrations of ions and gaseous molecules from the local environment. We are conducting experiments to calibrate the uptake of these “impurities” that we expect to serve as indicators of temperature, moisture, oxidation state and atmosphere composition. To date, our focus has been mainly on zircon (ZrSiO4), but we have recently turned our attention to quartz as well.

    ROADMAP OBJECTIVES: 1.1 4.1 4.3
  • Stoichiometry of Life - Task 2c - Field Studies - Other
    NAI 2012 Arizona State University Annual Report

    We continued analyses of organic matter in samples of porewaters from a deep ocean hydrothermal mound; concluded a study on element acquisition by biological soil crusts, and initiated a new study that may shed light on a recent hypothesis that floating pumice may have been a site for the origin of life. In this new study, the eruption of the Puyehue / Cordon Caulle volcano on 4 June 2011 near Bariloche, Argentina, provided a unique opportunity to investigate floating pumice as a unique habitat for microbial life. To assess this, we sampled floating pumice from various regional lakes to assess the make-up of the associated microbial communities using genomic techniques and to evaluate the use of key elements (nitrogen, phosphorus) by these microbes using chemical and isotopic methods.

    ROADMAP OBJECTIVES: 4.1 5.2 5.3 6.1
  • Stoichiometry of Life - Task 1 - Laboratory Studies in Biological Stoichiometry
    NAI 2012 Arizona State University Annual Report

    This project component involves a diverse set of studies of various microorganisms with which we are trying to better understand how living things use chemical elements (nitrogen, phosphorus, iron, etc) and how they cope, in a physiological sense, with shortages of such elements. For example, how does the “elemental recipe of life” change when an organism is starved for phosphorus or nitrogen or iron? Is this change similar for diverse species of microorganisms? Furthermore, how does an organism shift its patterns of gene expression when it is starved by various nutrients? This will help in interpreting studies of gene expression in natural environments, including extreme environments relevant to astrobiology.

    ROADMAP OBJECTIVES: 5.2 5.3 6.1 6.2
  • Project 6: The Environment of the Early Earth
    NAI 2012 Rensselaer Polytechnic Institute Annual Report

    This project involves the development of capabilities that will allow scientists to obtain information about the conditions on early Earth (3.0 to 4.5 billion years ago) by performing chemical analyzes of crystals (minerals) that have survived since that time. When they grow, minerals incorporate trace concentrations of ions and gaseous molecules from the local environment. We are conducting experiments to calibrate the uptake of these “impurities” that we expect to serve as indicators of temperature, moisture, oxidation state and atmosphere composition. To date, our focus has been mainly on zircon (ZrSiO4), but we have recently turned our attention to quartz as well.

    ROADMAP OBJECTIVES: 1.1 4.1 4.3