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Canadian Astrobiology Training Program (CATP)

Masters of Science candidates - To see a picture of the candidate place your cursor on their name

Name Institute Supervisor PDF/PhD/MSc/
Undergrad
Research area
Michael Angelopoulos
Michael Angelopoulos
McGill University
Dr. Wayne H. Pollard, Dr. Margaret Kalacska
MSc

The primary objective of this thesis is to evaluate how well CCR and GPR work in combination to measure absolute ice contents at Parsons Lake, a potential hydrocarbon development site. More specifically, under what environmental conditions and with what level of confidence are the tools successful? Extensive ice content, ground temperature, and stratigraphic data available at fine depth intervals for 25 boreholes will be correlated with geophysical responses. This project is significant for two reasons: (1) - Using geophysics, land use planners can estimate the subsidence susceptibility of an area using a cheaper, faster, and more environmentally friendly approach. (2) - Conclusions drawn can be used for potential Mars exploration programs focused on studying subsurface ice. Landforms indicative of ground ice in permafrost on Mars have been identified since the early flyby and orbiter missions of the late sixties and early seventies. A geophysical subsurface instrument package, including GPR and CCR would provide a comprehensive 3D representation of the subsurface structures. This data could be directly used for the validation of orbital data interpretation. As well, this package could be used as in conjunction with shallow surface drilling activity. The subsurface characterization produced by the proposed instruments should reduce the risk associated with any drilling operation and provide insight into lateral variations of periglacial features within the subsurface.

Rebecca Austin
Rebecca Austin
McGill University
Dr. Boswell Wing
Undergrad Working with André Pellerin on making clear the specific metabolic controls on isotopic fractionation during microbial sulfate reduction, with the broader goal of revealing the co-evolution of microbial sulfate reduction and Earth's surface environment.
Melissa Battler
Melissa Battler
University of Western Ontario
Dr. Gordon Osinski and Dr. Neil Banerjee
PhD I am mapping the mineralogy of saline perennial springs on Axel Heiberg Island, Nunavut, and looking for evidence of biomineralization primarily using microscopy. My findings may be helpful in the search for similar sites on Mars, which may have supported life in the past.
Genevieve Berard
Genevieve Berard
University of Winnipeg
Dr. Ed Cloutis
Undergrad Geological attributes of Mars analogue sites: East German Creek hypersaline springs and Lake St. Martin crater. Preliminary investigations at the East German Creek Mars analogue site in Manitoba suggest that the mineralogy at the site varies with distance from the discharge point. To address this issue we will look for any changes in the composition and structure of the minerals the precipitate in the spring discharge waters as a function of distance from the spring. This information will be used to analyse spectroscopic data for presumed spring deposits on Mars, to determine whether similar variations in mineralogy with distance from discharge points occur on Mars. The Triassic age Lake St. Martin impact crater in Manitoba hosts a thick sequence of presumed intracrater evaporite gypsum deposits that have been exposed by historic quarrying operations. These deposits will be examined to characterize weathering textures, analyse the nature of induration of gypsum sediments, and characterize glacial-gypsum interactions (scour marks, drag folds). The intent is to derive information that can be used in the analysis of imagery and spectroscopic data for gypsum-rich terrains on Mars.

Emma Bertran
Emma Bertran
McGill University
Dr. Boswell Wing
MSc

Sulfate reducing bacteria are important actors in the sulfur, carbon, and oxygen cycles. Their highly tuned metabolism produces characteristic isotopic fractionations evident in waste products (e.g., H2S) and in the metabolic substrates they utilize (e.g., SO42-). These sulfur isotopic signatures are then preserved in the rock record (eg., in grains of pyrite) as the fingerprint of microbial activity. They are used today by biogeochemists to infer the environmental characteristics of the early biosphere as well as to identify evidence for early microbial activity. These biogeochemical studies, however, rely on the assumption that the metabolism of sulfate reducers today and in the past has been the same. Experimental evolution can address this question by revealing the rate of change of microbial metabolism under specific stressors and its impact on sulfur isotopic fractionation. In order to experimentally determine the effects of changes in microbial metabolism on isotopic fractionation, it is essential to understand the experimental subject: Desulfuvibrio vulgaris. This sulfate reducer was chosen as guinea pig as it is well-studied and ubiquitous in anoxic environments worldwide.

The primary objective of my research project is to determine how a number of stress agents (salt –NaCl-, trace metals, low sulfate etc) acts as a selective pressure on D. vulgaris cultures. In order to achieve this objective we need to be able to quantify the growth characteristics of D. vulgaris as evolution proceeds. This will be performed with a high sensitivity protein assay as well as flow cytometry and quantitative tracking of specific genetic markers inserted in different populations of D. vulgaris. An endeavour of my initiative to this project will be to determine growth characteristics of sulfate reducers by using protein-specific tags to differentiate salt-adapted individuals from non-adapted ones. These tests are all being developed with one goal in mind: the determination of fitness (a measure of the growth of a descendant population compared to its ancestors under identical experimental conditions) with the highest accuracy possible. The fitness experiments must be done in order to demonstrate that a significant change in the metabolism of the bacteria, and thus adaptation to the novel conditions, occurred.

Emma Bertran Lheraud
Emma Bertran Lheraud
McGill University
Dr. Boswell Wing
Undergrad

The primary objective of my research project is to determine how salt (NaCl) acts as a selective pressure on Desulfuvibrio vulgaris cultures. In order to achieve this objective we need to be able to quantify the growth characteristics of D. vulgaris as evolution proceeds. This will be performed with a high sensitivity protein assay as well as flow cytometry and quantitative tracking of specific genetic markers inserted in different populations of D. vulgaris. An endeavour of my initiative to this project will be to determine growth characteristics of sulfate reducers by using protein-specific tags to differentiate salt-adapted individuals from non-adapted ones. These tests are all being developed with one goal in mind: the determination of fitness (a measure of the growth of a descendant population compared to its ancestors under identical experimental conditions) with the highest accuracy possible. The fitness experiments must be done in order to demonstrate that a significant change in the metabolism of the bacteria, and thus adaptation to the novel conditions, occurred.

Stéphanie Blain
Stéphanie Blain
University of Western Ontario
Dr. Gordon Osinski
Undergrad

I am assisting Melissa Battler in her research on biomineralization on Axel Heiberg Island.

Alyssa Cobb
Alyssa Cobb
McMaster University
Dr. Ralph Pudritz
MSc

From the experiments of Miller and Urey, we know that numerous amino acids may be synthesized through the machinations of Earth’s atmosphere. But the rest remain unaccounted for. Astrophysical processes are the next logical assumption in the discovery of how amino acids and other biomolecules become integrated into planetary systems. Dr. Ralph Pudritz has developed a research program on the origin of biomolecules, specifically amino acids, in planetesimals. This research includes the performing of chemistry simulations designed to discover the origin of amino acids in planetesimals and meteorites. As cited by Emberson and Pudritz (2011, in prep), carbon-rich meteorites contain organic matter such as amino and carboxylic acids. The meteoritic parent bodies are composed of rock and water ice as well as a variety of organic material, which they incorporated from solar nebulae in which they exist. Radionuclides decay in the center of these parent bodies, causing the interior to heat above the melting point of water. With liquid water and organic material now present, a process called aqueous alteration causes the organics to chemically alter their makeup, producing other organic materials, including amino acids. Planetesimals are built up by collisions with smaller bodies, so another consideration is the extreme temperature and pressure change during such impacts. This may produce non-equilibrium conditions affecting amino acid synthesis. Another aspect of amino acid delivery to planets is the encounter between a meteorite and planetary atmospheres and surfaces. Amino acids and other biomolecules would survive such an extreme event, but the intense temperature and pressure changes must be taken into account when considering meteorite impacts as the mode of arrival for planetary biomolecules. This, then, is my research objective: mimic the process of aqueous alteration inside a meteoritic parent body with the intent of predicting amino acid concentrations inside a typical meteorite.

Berivan Esen
Berivan Esen
University of Toronto
Dr. Barbara Sherwood Lollar and Dr. Greg Slater
MSc My research focus is on the drivers and mechanisms sustaining life in the deep terrestrial subsurface (2-3 km below the surface) within the Canadian Shield. Current Research Interests; - Using stable carbon isotopic techniques to develop an understanding of the origin, function, and cycling of volatile fatty acids in microbial communities. - The implications of deep microbial life for astrobiological studies related to the origin of life on Earth and the distribution of life in the solar system.
Yasuhiro Hasegawa
Yasuhiro Hasegawa
McMaster University
Dr. Ralph Pudritz
PhD I'm interested in photochemistry in protoplanetary disks. In particular, I'm investigating how amino acids is formed on icy grains in radiatively heated disks.
Matthew Izawa
Matthew Izawa
University of Western Ontario
Dr. Neil Banerjee and Dr. Roberta Flemming
PhD 1. Mineralogical astrobiology (microbe-mineral interaction and traces of microbial activity preserved in the rock record, as they pertain to the habitability of early Earth, Mars, and other bodies). Mineralogy is one of the royal roads to understanding environments of formation and alteration processes in geological samples, including those from other worlds. The above research areas are unified in that they use mineral structure, composition and assemblages to elucidate the history of samples from diverse environments which are relevant to early Earth and other planets. Specifically, we are investigating traces of microbial activity in basaltic glasses produced in seafloor volcanic environments. Microbial activity produces hollow etch structures that can be preserved for geologic timescales under favorable conditions. Because basalt (and, potentially, water-basalt interaction) is widespread in the solar system, notably on Mars, this represents a very widespread and ancient possible habitat for life. A combination of field, analytical, experimental simulation and computer modeling techniques are being applied to this problem. 2. Impact crater hydrothermal systems as a habitat for microbial life and microbial preservation, focusing on the well-preserved post-impact hydrothermal system at the Haughton impact structure, Devon Island, Nunavut. Impact cratering is a geologic process common to all planetary objects with solid surfaces. Impact-generated hydrothermal activity may occur wherever the target includes significant amounts of water. Understanding the impact crater as a habitat and potential ecological hotspot for diversification is of high potential relevance to studies of life on ancient Earth, Mars, and elsewhere. 3. Meteorite studies (mineralogy, geochemistry, petrology) as probes of the early solar system, including the environment(s) in which life emerged; and as samples of other solar system bodies (notably Mars) which may preserve a record of past habitable conditions.)
Guillaume Lamarche-Gagnon
Guillaume Lamarche-Gagnon
McGill University
Dr. Lyle Whyte
MSc

Recent explorations of the Canadian high Arctic led to the discovery of the first and thus far only known subzero (-5°C), hypersaline (24%), perennial spring originating from permafrost methane seeps on Earth (1). The environmental characteristics (cold temperatures, hypersalinity, methane-rich, etc.) of the Lost Hammer (LH) spring make it a potential Mars-analogue site, especially considering the recent discovery of spatial and seasonal variations in Mars atmospheric methane possibly originating from localized “hotspots” or “plumes”(2). Since methane can both serve as energy sources for certain microorganisms or be produced biologically, Mars methane is of important significance for astrobiology. Preliminary analyses of the LH spring and its outflow channels already revealed the presence of methanogens, but mainly of members of the poorly understood anaerobic methane oxidizing Archaea (ANME-1) which make up for the near totality of LH archaeal communities (1). My research project have for primary objective to determine whether or not LH microbial communities are capable of active anaerobic methane oxidation under in-situ conditions (i.e. -5ºC, hypersalinity) via measurements of isotopically labelled methane. Detecting biological methanogenesis and conclusively isolating and characterising subzero halophilic methanogens from saline spring sediments is also a goal of the present research.

Long Li
Long Li
University of Toronto
Dr. Barbara Sherwood Lollar
PDFSerpentinization (a process of hydrothermal alteration of olivine-bearing mantle rocks at relatively low pressure and temperature conditions) has been proposed to potentially support the energy and material required for the first life on Earth and other planets (if there is any). My research in Toronto mostly employs lab experiments, field observations and numerical modeling to examine the cycling of some life-constituting elements, particularly nitrogen and carbon, in the Archean serpentinite settings, their interplay with the deep biosphere and the implications to early life.
Liane Loiselle
Liane Loiselle
University of Western Ontario
Dr. Gordon Southam
PhD

I am investigating the biomineralization products generated by acidophilic bacteria that were found in the Rio Tinto river in Spain; a Martian analogue site. Biologically cultured and inorganically synthesized precipitates are being characterized using geochemical methods and molecular techniques in order to assert the presence of biosignatures.

John E. Moores

John E. Moores
University of Western Ontario/Centre for Planetary Science and Exploration
Dr. Gordon Osinski
PDF Assessing habitability is the first step in determining where life may have arisen and where it may still persist elsewhere in our Solar System. Within these broad strokes, it is important to recognize that even in largely inhospitable regions, isolated pockets may persist in which conditions are sufficiently clement to shelter biological systems or biomarkers. Thus, my work focuses on understanding the potential for habitability of Mars, in particular for ice-wedge polygons and other small-scale geomorphologic terrains in the Northern Arctic. I seek not only to determine whether it is possible that these kinds of features are indeed "safe harbours" of life in the present era, but also I hope to help determine robotic techniques by which we may explore them.
Nadia C.S. Mykytczuk
Nadia C.S. Mykytczuk
McGill University
Dr. Lyle Whyte, Dr. Boswell Wing, Dr. Barbara Sherwood-Lollar
PDFThe microorganisms that inhabit Earth’s extremely cold environments, such as permafrost saline springs in the Canadian High Arctic, represent the best analogues for life that might be found in Martian liquid water habitats and methane plumes.My research projects will target the collective molecular traits of microbial communities in two extreme analogue sites: the Gypsum Hill (GH; 7.5% salinity, -1.3 to 7 °C water temperature, air temperatures typically below - 40 °C) and Lost Hammer (LH; 23 % salinity, 12 to -18 °C sediment temperature, 50% methane) springs on Axel Heiberg Island. The primary goal will complete metagenomic analyses of the GH chemoautotrophic, sulfur oxidizing, phototrophic-independent microbial streamers (predominantly Thiomicrospira sp.), as well as the anaerobic methane-oxidizing LH sediment community. Profiling the metaproteome will further uncover the predominant metabolic enzymes required for microbial energetics in sulphur and methane-rich conditions. In situ geochemical and isotopic analyses of the sites will determine the biogeochemical sulphur and methane cycling. Together, the meta-genomic/proteomic analyses combined with geochemical tracing offer a powerful method to uncover the mechanisms for microbial interactions within these extreme subzero hypersaline cryoenvironments.
Christopher R. Omelon
Christopher R. Omelon
University of Western Ontario
Dr. Gordon Southam
PDF My research explores the diversity and activity of microbial communities in aquatic and terrestrial habitats and the role bacteria play through biogeochemical interactions in shaping both past and present natural environments. My long-term goals are to understand relationships between the geochemical environment and microbial diversity by identifying key geochemical processes that, when combined with microbial and molecular analyses, explain how microorganisms are involved in complex processes such metal sorption, redox transformations, nutrient and element cycling, and biomineralization. My scientific approach aims to develop novel hypotheses that help our understanding of how microrganisms influence the geochemistry of natural systems through the use of a wide array of field and laboratory tools and techniques, including exciting recent developments in electron microscopy and synchrotron radiation. My current research direction focuses on the geochemical dynamics of microbe-mineral environments, including both physiological and phylogenetic investigations cryptoendolithic habitats as well as examination of the cell-surface reactivity of bacteria directly involved in the weathering of sedimentary rocks – a process of potential global importance for silicate weathering and carbon sequestration studies. In addition to my primary research, I am studying the mechanisms for biologically induced carbonate precipitation and microbialite formation in Pavilion Lake, British Columbia, the speciation and cycling of arsenic and antimony in the El Tatio geothermal fields of northern Chile, the molecular and physiological diversity of thermophilic arsenite-oxidizing and arsenate-reducing bacteria from this habitat, as well as microbe-mineral interactions in a wide geographic range of other natural environments.
Alexandra Pontefract
Alexandra Pontefract
University of Western Ontario and Open University
Dr. Gordon Osinski, Dr. Gordon Southam and Dr. Charles Cockell
PhD Meteorite impact events have the ability to simultaneously destroy, as well as create habitats for life. Though capable of generating extreme temperatures and pressures within the target lithology, these processes can favourably change the availability and habitability of the substrate for lithophytic organisms, which are then able to colonize microfractures and pore spaces created during the impact. This project focuses on the correlation between shock level and the extent of endolithic growth within shocked gneisses from Haughton Crater, Devon Island, Canada.
Kristyn Rodzinyak
Kristyn Rodzinyak
McGill University and Canadian Space Agency
Dr. Boswell Wing and Dr. Richard Leveille
MSc

My thesis work involves investigating sulfur isotopes and their implications on atmospheric oxygen and planetary surface environments. I’m looking at four greenstone belts in Northwestern, Ontario to determine if rock type affects the sulfur isotope ratios preserved in the rock record. I’m interested in rocks dated 2.8-3.0 billion years old where sulfur isotopes, especially sulfur 33, have implications for atmospheric oxygen variations. Additionally, I’m working on a Mars analogue site through a Research Assistantship Program with the Canadian Space Agency. Pyrite nodules are present in a cold, dry, buffered environment in the Canadian Arctic and are being oxidized to hematite and jarosite – a mineral generally associated with warm, acidic environments and a prevalent mineralogical component of the Martian surface.

Pablo Sobron Sanchez
Pablo Sobron Sanchez
Canadian Space Agency (CSA)
Dr. Richard Leveille (CSA), Dr. Boswell Wing (McGill University), Dr. Ed Cloutis (University of Winnipeg)
PDF My research is mainly aimed to understand the conditions that led to the formation of (hydrated) sulfates and other minerals such as phyllosilicates on Mars, and if biomediation is a possibility. Joining CATP will allow me to characterize active, gas-dominated, basalt-hosted, acid-sulfate weathering systems on Earth as potential bio/geo/mineralogical analogs. Understanding analog basaltic acid-sulfate systems on Mars-like settings and their ability to support life provides a way to assess the astrobiological potential of early Mars.
Haley Morgan Sapers
Haley Morgan Sapers
University of Western Ontario
Dr. Gordon R. Osinski and Dr. Neil Banerjee
PhD Any hypervelocity impact into a water-rich target has the potential to create a post-impact hydrothermal system. Such impact-induced environments may be conducive to microbial colonization. It is generally accepted that microbes colonize submarine basaltic glass leaving characteristic tubular and granular etch structures. Examination of glasses from the Ries impact structure, Germany, has revealed tubular textures with remarkably similar morphologies to the bioalteration textures observed in basaltic glasses. Using various analytical techniques, my research focuses on elucidating the origin and, if indicated, establishing the biogenicity of the enigmatic tubular textures in the Ries impact glasses.
Clinton Scott
Clinton Scott
McGill University
Dr. Boswell Wing
PDF
Jared Shivak
Jared Shivak
University of Western Ontario
Dr. Neil Banerjee
MSc

On the Earth, endolithic microbial life has been known to colonize and thrive in the subsurface by drawing energy and nutrients from the rocks and fluids within the crust. Martian meteorites currently represent the only samples of the Martian crust that terrestrial scientists have access to. They show many similarities to terrestrial rocks which are known to be important microbial habitats, such as seafloor basalts. My work aims to mineralogically and geochemically characterize a suite of Martian meteorites and evaluate how they have been altered and what potential microniches they present to microbial life, should it have been present on Mars during its history. The aqueous history of the rocks as well as the possible energy and nutrient sources they present are key factors to consider when attempting to evaluate the potential habitability of the Martian subsurface. This has implications on the future of Mars exploration; instrument and target selection for missions searching for evidence of life depend on a full understanding of where life would be expected to survive and flourish on Mars. I am also involved with research modelling the stability and detectability of groundwater in the regolith of polar regions on Mars and the implications that has on habitability.

Danielle Simkus
Danielle Simkus
McMaster University
Dr. Greg Slater
MSc

The discovery of biosignatures on other planets may be interpreted as evidence for the existence of extraterrestrial microbial life. Preserved in the geologic record, these signatures can also provide us with information about the timing and sequence of events leading to the origin of life. My focus is on distinguishing between biosignatures and abiosignatures within extreme environments. For my Master’s research project, I am analyzing the concentrations and isotopic compositions of organic compounds, such as volatile fatty acids and lipids, present in deep terrestrial subsurface environments in Ontario and South Africa. By investigating these Martian analogue sites, I hope to gain insight into the potential for life on Mars, as well as the history of life on Earth.

Sarah Soles
Sarah Soles
McMaster University
Dr. Greg Slater
MSc

My research utilizes analogue environments, Pavillion and Kelly Lakes (British Columbia; Canada), which reflect the biogeochemical processes active on the primitive Earth and possibly on other planets such as Mars. The objectives are to: 1) identify a possible biosignature associated with photosynthetically-influenced carbonate precipitation within microbialite nodules in Kelly Lake and 2) compare these results to biosignatures formed by photosynthetic influences on isotopic geochemistry discovered within microbialites in the near-by Pavillion Lake. This will be completed through stable isotope analysis (δ13C and δ18O), molecular analysis of the microbial phospholipid fatty acids, and imaging of microbialite-associated microbial communities. The results from these experiments will indicate whether the microbialite formation mechanisms active in Pavillion Lake, along with their associated biosignatures, are found among similar systems such as Kelly Lake. This may have large implications in the understanding of biosignature formation and the use of these markers in the search for extra-terrestrial life.

Jessica Stromberg
Jessica Stromberg
University of Western Ontario
Dr. Neil Banerjee and Dr. Gordon Southam
MSc

My project is involved with the geochemistry and biosignatures in Archaean age metasedimentary rocks in the Abitibi greenstone province of the Canadian Shield. In particular the ankerite veins hosted within the Late Archean Tisdale (2707 – 2705 Ma) and Porcupine (2685 – 2673 Ma) assemblages in the Dome Mine, Timmins, Ontario, Canada. The potential sub-seafloor formation of this ankerite vein is of particular interest and by looking at the mineralogy and isotopes, the environmental conditions of the hydrothermal system and biosphere can be constrained and confirm whether it was a sub seafloor deposit. As well, I will be exploring the preservation potential for organic biosignatures in this deposit by looking at the mineralogy, isotopic signatures and organic compounds present.

Jessica M. Stromberg
Jessica M. Stromberg
University of Winnipeg
Dr. Ed Cloutis
Undergrad

Geological attributes of Mars analogue sites: East German Creek hypersaline springs and Lake St. Martin crater. Preliminary investigations at the East German Creek Mars analogue site in Manitoba suggest that the mineralogy at the site varies with distance from the discharge point. To address this issue we will look for any changes in the composition and structure of the minerals the precipitate in the spring discharge waters as a function of distance from the spring. This information will be used to analyse spectroscopic data for presumed spring deposits on Mars, to determine whether similar variations in mineralogy with distance from discharge points occur on Mars. The Triassic age Lake St. Martin impact crater in Manitoba hosts a thick sequence of presumed intracrater evaporite gypsum deposits that have been exposed by historic quarrying operations. These deposits will be examined to characterize weathering textures, analyse the nature of induration of gypsum sediments, and characterize glacial-gypsum interactions (scour marks, drag folds). The intent is to derive information that can be used in the analysis of imagery and spectroscopic data for gypsum-rich terrains on Mars.

Laura Thomson
Laura Thomson
University of Western Ontario
Dr. Gordon Osinski, Dr. Wayne Pollard
MSc

The aim of my thesis is to determine whether ground penetrating radar (GPR) is an effective tool in characterizing the nature ground ice. I will be collecting high resolution GPR data over ground ice of various origins in the Canadian arctic this summer, and subsequently correlating this data with the chemical and electrical properties of permafrost cores collected at the survey site. Similar studies have been performed on glacial ice and I'm testing whether they are also suitable techniques for ground ice research.

Dusa Vukosavljevic
Dusa Vukosavljevic
University of Western Ontario
Dr. Gordon Southam, Dr. Neil Banerjee
MSc

Possible Archean mineral/microbial interactions: laboratory model of microbial growth on serpentinized and non-serpentinized mineral surfaces

Serpentinization reactions in peridotite-hosted systems such as Lost City Hydrothermal Field could have been common in near surface waters during the Archean (2.5-3.8 billion years ago) [1]. These processes would have presumably occurred alongside the early biosphere, containing methanogens and dissimilatory sulfate reducing bacteria. Within photic regions of Archean oceans, cyanobacteria could have produced oxygen oases via oxygenic photosynthesis [2]. Fayalite, enriched from fayalite-magnetite iron ore (Forsythe Iron Mine, Quebec), was reacted with synthetic, anoxic Archean seawater for 6 months at 120oC. This serpentinization model system increased silica concentration in fluid phase and produced secondary minerals (i.e., chrysotile) on fayalite mineral surfaces. Scanning electron microscopy (SEM) revealed Methanococcus voltae and Desulfovibrio spp. preferred colonizing serpentinized versus non-serpentinized mineral surfaces. Colonization by Desulfovibrio spp. was enhanced by the formation of extra-cellular polymeric substances. Using SEM-energy dispersive x-ray analysis, the sulfate reducing bacteria were also found to produce iron sulfides suggesting that dissimilatory sulfate reduction was active on the serpentinized mineral surfaces. In contrast to more selective colonization by Methanococcus and Desulfovibrio, cyanobacteria grew as a mat across the fayalite ‘sediment’ surface. Detection of CH4 and O2 in gas phase indicated growth of methanogens and cyanobacteria in their respective reaction systems. Cyanobacterial growth increased pH of reaction system, catalyzing CaCO3 precipitation on cyanobacterial cell surfaces. Physically ‘tearing’ the mat from the mineral sediment surface during SEM sample preparation resulted in distinctive filamentous molds within an exopolymeric matrix. This is comparable to tidal flows tearing biofilms in natural systems, indicating cyanobacteria possess stronger affinity for the mineral substrate than biofilm. It also created unique casts of the cyanobacteria that if fossilized would produce unique biomarkers.

Lori Ziolkowski
Lori Ziolkowski
McMaster University
Dr. Greg Slater
PDF My postdoctoral work is investigating the carbon cycling of endolithic communities, or communities that grow in the cavities of porous rocks. These communities have been identified in mid-latitude and polar deserts. I am investigating the correlation between community structure and turnover these endolithic communities.