Northwestern University Evanston, IL Welcome to Northwestern University and the Seventh Annual Midwest Geobiology

EOBIOLO T G G ES Y 2 W 0 D 1 I 8 M

N O Y IT R S TH R W E E IV STERN UN

Midwest Geobiology Symposium 2018 October 6, 2018 Northwestern University Evanston, IL Welcome to Northwestern University and the seventh annual Midwest Geobiology

Symposium. This event provides a unique opportunity for graduate students and post- doctoral scholars to share ongoing research within the local geobiology community.

The focus of this event is to give these emerging scholars a platform at which to discuss science, and to build networking and communication skills with peers and established members of the field. This regional symposium is an annual event that has been ongoing since inception at University of Washington in St. Louis in 2012. At this year’s symposium we have approximately 95 participants from 20 institutions, presenting a diverse array of research spanning many areas of geobiology. We thank the Agouron

Institute, NAISE, the Northwestern Nemmer’s Prize in Earth Sciences, and Northwestern

University for providing generous support for this meeting.

Sincerely,

The Midwest Geobiology 2018 Organizing Committee

Magdalena Osburn (Northwestern University) Theodore Flynn (Argonne National Laboratory) Caitlin Casar (Northwestern University) Jamie McFarlin (Northwestern University) Table of Contents

Schedule...... 1

Speakers...... 2

Keynote...... 4

Posters...... 5

Participants...... 8

Map...... 11

Abstracts (in alphabetical order by presenting author)...... 12 Schedule Friday, 5 October 2018

6:30 pm - 9:30 pm Welcome reception at the Celtic Knot

Saturday, 6 October 2018

8:00 am - 9:00 am Arrival at Northwestern McCormick Center and Breakfast

9:00 am - 9:10 am Opening remarks

9:10 am - 10:30 am Oral session 1

10:30 am - 10:50 am Coffee break

10:50 am - 12:30 pm Oral session 1, continued

12:30 pm - 1:40 pm Lunch

1:40 pm - 3:00 pm Oral session 2

3:00 pm - 3:20 pm Coffee break

3:20 pm - 4:00 pm Oral session 2, continued

4:00 pm - 4:45 pm Keynote speaker

4:45 pm - 7:30 pm Poster session with snacks and bar service

7:45 pm Optional gathering at Bat17

1 Speakers Oral Session 1

9:10 am - 9:30 am Justin Podowski, University of Chicago Compositional and metabolic differences in nitrifying communities across the Laurentian Great Lakes

9:30 am - 9:50 am Kathyrn Hobart, University of Minnesota Understanding Microbial Contributions to Pyrrhotite Oxidation at Circumneutral pH

9:50 am - 10:10 am Caitlin Casar, Northwestern University Mineral-hosted biofilm communities within the continental deep subsurface

10:10 am - 10:30 am Samuel Miller, University of Chicago Novel Metaproteomic Approaches Applied to Arctic Soils Reveal Niche Partitioning of Microbial Biogeochemical Functions and Systematic Variations with Vegetation Type

10:50 am - 11:10 am Scott Beeler, Washington University in St. Louis Interpreting the meaning of extreme isotopic enrichments in modern microbialites and implications for the rock record

11:30 am - 11:50 am Roger Bryant, Washington University in St. Louis Local Environmental Controls on Marine Sedimentary Pyrite Sulfur Isotope Ratios

12:10 pm - 12:30 pm Derek Smith, Washington University in St. Louis Changes in Bacterial Growth Rate Lead to Hydrogen Isotope Fractionation

2 Oral Session 2

1:40 pm - 2:00 pm Daniel Jones, University of Minnesota Mercury methylation and methylating communities in sulfate- impacted freshwater ecosystems

2:00 pm - 2:20 pm Clayton Johnson, University of Notre Dame Developing and utilizing a novel cadmium-specific fluorescent probe technique to test the component additivity approach to surface complexation modeling

2:20 pm - 2:40 Stephan Hlohowskyj, Central Michigan University Molecular geochemistry of molybdenum-organic matter interactions in black shales

2:40 pm - 3:00 pm Mary Sabuda, University of Minnesota Biogeochemical transformations of selenium by common saprotrophic soil fungi

3:20 pm - 3:40 pm Jocelyn Richardson, Washington University in St. Louis The source of sulfate in biogenic calcite: insights from μ-XRF imagine, XANES spectroscopy and isotope studies of ancient and extant brachiopods

3:40 pm - 4:00 pm Stephanie Olson, University of Chicago Ediacaran oxygen oases and the emergence of bilaterian burrowing

Keynote Speaker

4:00 pm - 4:45 pm Francis Albaréde, Ecole Normale Supérieure de Lyon Transition metals, their isotopes, and biology

3 Keynote Speaker 4:00 pm - 4:45 pm

TRANSITION METALS, THEIR ISOTOPES AND BIOLOGY Francis Albaréde Ecole Normale Supérieure de Lyon

The natural variations of stable isotopes of transition elements in biological material offer a novel perspective on metal functionalities and pathways in the cells of unicellular and multicellular organisms. Three transition elements have found critical roles in biological processes, Cu, Zn, and

Fe. Their cellular homeostasis is rather well understood, although some critical links are still miss- ing. For the microbiologists, tasks of different nature are calling for geochemist’s attention. First, a huge analytical investment is needed to describe the extent of isotopic variability in different cell components and organelles. Second, predicting the isotope fractionation caused by the different cellular components using theoretical (ab initio) methods is a task best handled by theoretical chemists and biochemists. Third, testing the isotopic expression of the genes involved in metal homeostasis (e.g., importer, oxidoreductases, storage) requires a close interaction between molecular biologists and geochemists. Fourth, quantitative and robust models of homeostasis should be put together in order to demonstrate that our understanding of the processes account for the observations. Fifth, it is hoped that interaction between cells and their environment can be traced by specific biomarkers. On each part, decisive progress has been achieved over the last decade, but what is now known as ‘Isotope Metallomics’ is still in infancy. The purpose of this talk is to review these principles and to provide some applications to biology and medicine.

4 Posters Jake Bailey, University of Minnesota Carbonate dissolution by sulfur-oxidizing bacteria in marine cold seep settings

Evelyn Becerra, Indiana University- Purdue University Indianapolis A High Resolution Study of Nutrient and Redox Cycling in the Kope Formation of the Late Ordovician

Jake Callaghan, University of Minnesota Duluth New spin on methylotrophy in a freshwater sediment: Novel archaeal phylum implicated in methyl compound degradation

Howard Chase, Indiana University Purdue University Indianapolis Spatial and Temporal Variations of Water Quality in a Eutrophic Freshwater Lake and Their Correlation to Seasonal Algal Blooms

Sarah Denny, Indiana University Purdue University Indianapolis Phosphorus Uptake in Constructed Wetlands for Possible Nutrient Loading Mitigation

Fotios Fouskas, Indiana University Purdue University Indianapolis Sulfurization pathways in modern euxinic lakes: Exploring the key constraints for organo-sulfur and pyrite formation

Gwendolyn Gallagher, University of Chicago Physiology and Protein-Level Proteorhodopsin Expression Patterns in Vibrio campbellii CAIM 519

Alyssa Henke, Indiana University Purdue University Indianapolis Using Reactive Iron Distribution to Characterize Redox Conditions in the late-Holocene record of Martin Lake, USA

Jennifer Houghton, Washington University in St. Louis Evaluating proxies of microbial carbon and sulfur cycling in methane seep sediments

Ioanna Koltsidou, Indiana University Purdue University Indianapolis Assessment of Microbial Community Composition in Eagle Creek Reservoir using 16S Next Generation Sequencing and qPCR

Robert Kupper, Washington University in St. Louis Assessment of Microbial Community Composition in Eagle Creek Reservoir using 16S Next Generation Sequencing and qPCR

5 Martin Kurek, Indiana University Purdue University Indianapolis Rates and Products of Fe(II) Oxidation in Trioctahedral Smectites

Maisie Lenards, University of Minnesota Metagenomic analysis of a novel potential mercury-methylating population from a hypereutrophic, sulfidic lake

Barbara MacGregor, University of Minnesota Sequencing read distribution in bacterial genomes with and without GC skew

Jamie McFarlin, Northwestern University A new global synthesis of sedimentary leaf wax isotopes: expanding to include the Arctic

D’Arcy Meyer-Dombard, University of Illinois at Chicago The deep biosphere in the jungle: following carbon in serpentinizing springs in a tropical surface biome

Senthil Murugapiran, University of Minnesota Exploring the “microbial dark matter’’ through large-scale genomics

Edward O’Loughlin, Argonne National Laboratory Effects of Fe(III) inputs on the rate of methanogenesis in wetland sediment microcosms

Jaclyn Oliver, Central Michigan University Reconstructing methane-supplemented foodwebs using carbon isotope analysis of aquatic invertebrate remains in North American lake sediments

Elizabeth Olson, Northern Illinois University Isotopic disequilibrium in Prosopis tree cellulose as an indicator of water stress and hydroclimate variability

Lindsay Putman, Michigan Sate University Assessing Microbial Community Assembly in a Serpentinization-Influenced Aquifer over Time

Kathryn Rico, University of Michigan Sediment trace metal contents do not reflect porewater chemistry in a low-oxygen Precambrian analogue

Annette Rowe, University of Cincinnati Microbes, Minerals and Electrodes at the Sanford Underground Research Facility (SURF): Electrochemistry 4000 ft below the surface

Cody Sheik, Large Lakes Observatory Microbial contributions to the sediment N and C isotopic record 6 John Shukle, Indiana University Purdue University Indianapolis Phosphorous speciation and mobility in Missisquoi Bay mesocosms under extended conditions of reduction, oxidation, and fluctuating oxidation-reduction

Benjamin Tiger, Washington University in St. Louis Preliminary biogeochemical characterization of sediments from Lake Sibinacocha, Peruvian Andes

Gabriel Vargas, University of Chicago Illuminating environmental and molecular controls on aerobic anoxygenic phototrophy

R. Seth Wood, Washington University in St. Louis Formation and Stabilization of Biogenic Vaterite

Ming Wu, Washington University in St. Louis Mixed sources of n-alkanes in the late Ediacaran in the East European platform constrained by Primary Compound-specific hydrogen isotopic composition

Allie Wyman, University of Illinois Salinity information from lipid biomarker isotope ratios in a central tropical Pacific lake sediment record

Ziming Yang, Oakland University The Influence of Earth Abundant Minerals in Deep Ocean Hydrothermal Organic Transformations

Qiang Yu, University of Notre Dame Adsorption of selenite onto bacillus subtilis: the overlooked role of cell envelope sulfhydryl sites in the microbial conversion of Se(IV)

7 Participants

First Name Last Name Institution Francis Albaréde Ecole Normale Supérieure de Lyon Nouf Aldossari University of Minnesota Jake Bailey University of Minnesota Evelyn Becerra Indiana University Purdue University Indianapolis Patricia A. Beddows Northwestern University Scott Beeler Washington University at St. Louis Sarah Ben Maamar Northwestern University Clara Blättler University of Chicago Alex Bradley Washington University at St. Louis Roger Bryant Washington University at St. Louis Jake Callaghan University of Minnesota Duluth Caitlin Casar Northwestern University Howard Chase Indiana University Purdue University Indianapolis Luoth Chou University of Illinois at Chicago Chris H. Crosby Oakton Community College Sarah Denny Indiana University Purdue University Indianapolis Greg Druschel Indiana University Purdue University Indianapolis Jeremy Fein University of Notre Dame David Fike Washington University at St. Louis Theodore Flynn Argonne National Laboratory Fotios Fouskas Indiana University Purdue University Indianapolis Gwendolyn Gallagher University of Chicago Bill Gilhooly Indiana University Purdue University Indianapolis Trinity Hamilton University of Minnesota Leanne Hancock Michigan State University Dalton Hardisty Michigan State University Benjamin Harrison Central Michigan University Jeff Havig University of Minnesota Alyssa Henke Indiana University Purdue University Indianapolis Stephan Hlohowskyj Central Michigan University Kathryn Hobart University of Minnesota Jennifer Houghton Washington University at St. Louis Jack Hutchings Washington University at St. Louis Andy Jacobson Northwestern University Clayton Johnson University of Notre Dame Daniel Jones University of Minnesota 8 First Name Last Name Institution Ioanna Koltsidou Indiana University Purdue University Indianapolis Bronwen Konecky Washington University at St. Louis Joshua Kuether University of Minnesota Robert Kupper Washington University at St. Louis Martin Kurek Indiana University Purdue University Indianapolis Sohyun Lee Northwestern University Maisie Lenards University of Minnesota Barbara MacGregor University of Minnesota Andy Masterson Northwestern University D’Arcy Meyer-Dombard University of Illinois at Chicago Samuel Miller University of Chicago Senthil Murugapiran University of Minnesota Adam Nuccio Northern Illinois University Connor O’Loughlin Downers Grove South High School Edward O’Loughlin Argonne National Laboratory Jaclyn Oliver Central Michigan University Stephanie Olson University of Chicago Elizabeth Olson Northern Illinois University Maggie Osburn Northwestern University Joseph Pasterski University of Illinois at Chicago Justin Podowski University of Chicago Lindsay Putman Michigan State University Jocelyn Richardson Washington University at St. Louis Kathryn Rico University of Michigan Megan Rohrssen Central Michigan University Annette Rowe University of Cincinnati Fabrizio Sabba Northwestern University Mary Sabuda University of Minnesota Jarunetr Sae-lim Washington University at St. Louis Sarah Schroeder University of Minnesota Matt Selensky Northwestern University Cody Sheik University of Minnesota Duluth John Shukle Indiana University Purdue University Indianapolis Derek Smith Case Western Reserve University Hammy Sorkin Washington University at St. Louis Melanie Suess Washington University at St. Louis Wesley Swingley Northern Illinois University Benjamin Tiger Washington University at St. Louis

9 First Name Last Name Institution Howard Truong Northwestern University Brooke Vander Pas Indiana University Purdue University Indianapolis Gabriel Vargas University of Chicago Yubo Wang Northwestern University George Wells Northwestern University R. Seth Wood Washington University at St. Louis Ming Wu Washington University at St. Louis Allie Wyman University of Illinois Ziming Yang Oakland University Qiang Yu University of Notre Dame

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11 T I O S S R R E E V I M N E U Abstracts In alphabetical order by presenting author

12 Carbonate dissolution by sulfur- A High Resolution Study of oxidizing bacteria in marine cold seep Nutrient and Redox Cycling in settings the Kope Formation of the Late rdovician Dalton Leprich, Beverly Flood, Elizabeth Ricci, Peter Schroedl, Jake O Bailey Dept. Of Earth Sciences, University of Minnesota., Minneapolis, MN Becerra, E.S.1, Gilhooly, W.P.1, Dattilo, B.F.2, Orazi, D.L. 55455, USA 1Indiana University-Purdue University Indianapolis, 2Purdue University Fort Wayne We observed an affinity for the colonization of carbonate rocks by sulfide-oxidizing bacteria The Ordovician (485-444 Mya) was a period of at marine methane seeps. These bacteria evolutionary and climatic change; it began with commonly co-occur with etch pits that suggest The Great Ordovician Biodiversification Event active dissolution. Aerobic sulfide oxidation is (GOBE), which caused a rapid increase in an acid-producing reaction that has the potential diversity and dramatic changes in paleoecology, to dissolve carbonate minerals. We investigated and ended with the Hirnantian Glaciation which carbonate dissolution in the laboratory using is thought to have caused the first major mass bioreactors that contain sulfur-oxidizing extinction of the Paleozoic resulting in the loss bacteria growing on calcium carbonate rock of ~85% of marine species. Though several chips. The bioreactors were inoculated with studies document long time-scale changes Celeribacter baekdonensis LH4, and run under in geochemistry, there is currently a lack of continuous flow conditions for 21 days. The high resolution geochemical data that can pH, alkalinity, [Ca2+], and OD were monitored elicit different interpretations concerning the daily. Aragonite coupons were aseptically Ordovician biosphere. The Kope formation sampled and weighed over three weeks to within the Cincinnatian contains a series determine the rate of dissolution. The biotic and of interbedded mudstone and fossiliferous abiotic dissolution rates were ~1774 μmol•cm- limestone beds deposited within a shallow 2•a-1 and ~358 μmol•cm-2•a-1, respectively. epeiric sea. Its well established C-isotope, Select coupons were transferred to a flow-cell lithologic, and biostratigraphic records allow at the end of the experiment. Laser-scanning for a controlled environment to study smaller confocal microscopy revealed steep pH scale nutrient cycles not previously recorded. gradients within the biofilms. Our results show Preliminary N-isotope analysis of a high- that C. baekdonesis LH4 biofilms are actively resolution section of the Kope formation shows dissolving aragonite coupons by producing what appears to be an overall positive excursion acidic microenvironments, even under well- as well as smaller scale cycles based on lithology buffered conditions. These results support the suggesting broader scale studies overlook these hypothesis that sulfide-oxidizing bacteria in small time-step cycles. In this study, high marine seafloor settings can increase the rate resolution bulk N-isotopes and redox proxies of carbonate dissolution by decreasing the pH will be used on a core section above and below within the biofilm, and in the process, flux existing N-isotope data to determine nutrient carbon from the carbonate rock reservoir to the and redox cycles not previously recorded for ocean and atmospheric carbon reservoirs. this basin leading into the end Ordovician mass extinction.

13 Interpreting the meaning of extreme Local Environmental Controls on isotopic enrichments in modern Marine Sedimentary Pyrite Sulfur microbialites and implications for Isotope Ratios the rock record Roger N. Bryant1, Clive Jones1, Itay Halevy2, Virgil Pasquier2, William M. Berelson3, Alex L. Sessions4, David A. Fike1 Scott R. Beeler1, Fernando J. Gomez2, Alexander S. Bradley1 1Department of Earth and Planetary Sciences, Washington University 1Dept. of Earth and Planetary Sciences, Washington Univeristy in in St. Louis, St. Louis, MO, USA,2Department of Earth & Planetary St. Louis, St. Louis, USA, 2Laboratoria de Análisis de Cuencas, Sciences, Weizmann Institute of Science, Rehovot, Israel,3Department CICTERRA-CONICET, Facultad de Ciencias Exactas, Fisicas y of Earth Sciences, University of Southern California, Los Angeles, Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina CA, USA,4Division of Geological & Planetary Sciences, California Institute of Technology, Pasadena, CA,USA Microbialites are among the earliest and longest lasting records of life on Earth. Controls on the sulfur isotope (δ34S) composition Analyzing the stable isotopic composition of of sedimentary pyrite are poorly understood and carbonate minerals that comprise microbialites changes in bulk d34S values can be attributed is a commonly used tool to understand the to multiple biological and/or environmental environmental conditions associated with their causes. To address this, we performed grain- formation. However, the isotopic signatures specific S isotope analyses on pyrites extracted associated with different processes may be from modern marine sediments, using non-unique and determining which process Secondary Ion Mass Spectrometry (SIMS). is responsible for an isotopic signature can 34 For a site in NW Mediterranean, bulk δ Spyr in be difficult. Investigating the processes that interglacials is low and invariant and high and generate isotopic signatures in microbialites in variable for glacials. We show that samples modern environments can improve our ability from interglacials feature a narrow inter-grain to interpret similar signatures in the rock record. 34 distribution in δ Spyr, generally close to −45‰, We analyzed the processes driving the isotopic whereas samples from glacials feature a large evolution of lake waters from the modern inter-grain range, from ~−50 to ~110‰. A microbialite forming environment of Laguna sample from Santa Barbara Basin also features Negra, Argentina in order to better understand 34 13 18 a large inter-grain range in δ Spyr, from −42‰ extreme enrichments in C and O previously 34 to 29‰, but a high average δ Spyr value of described in microbialites and associated non- ~24‰. For each sample, little to no intra- microbial carbonates from the lake. Modern grain d34S variation was detected in grains lake waters showed isotopic enrichments large enough for multiple analyses. Our results comparable to those preserved in carbonates suggest that, (i) the biological fractionation (εbio) that can be explained through a combination from microbial sulfate reduction (MSR) was of evaporation, degassing, and carbonate invariant, both between sites and over time at precipitation. Together these results suggest the Mediterranean site, (ii) rapid sedimentation that the isotopic enrichments in microbialites can induce closed-system pore water evolution, record information regarding the environmental resulting in more 34S-enriched bulk pyrite, and conditions of the lake waters in which they 34 (iii) the shapes of inter-grain δ Spyr distributions formed. However, despite being associated in closed systems reflect the relative rates of with microbially generated minerals isotopic MSR and pyrite formation. These distributions enrichments can have an abiotic origin. can thus be used to infer sedimentation patterns and iron availability and reactivity.

14 New spin on methylotrophy in mineral-hosted biofilm communities a freshwater sediment: Novel within the continental deep archaeal phylum implicated in subsurface methyl compound degradation C. P. Casar1, M. R. Osburn1, T. M. Flynn2, A. L. Masterson1, B. R. Kruger3 Jake Callaghan1, Cody Sheik1 1Northwestern University (Evanston, IL), 2Argonne National 1University of Minnesota Duluth, Duluth MN Laboratory (Argonne, IL), 3Desert Research Institute (Las Vegas, NV)

Subsurface ecosystems are one of the least Minerals are likely an important energy source explored habitats on Earth, but we do know they for biofilm-forming members of the deep host a broad diversity of microorganisms and a continental biosphere in which other substrates significant amount of Earth’s surface biomass. are limited. However, the microbial ecology While organic rich marine sediments have been and constituent microbe-mineral interactions in well studied, freshwater systems remain largely these environments are not yet well understood under sampled. Using Lake Superior sediments, due to sampling challenges. We investigated we sought to understand the biogeochemical the utilization of minerals as lithotrophic roles of microorganisms in a low carbon, energy sources by biofilm communities freshwater setting. Using a shotgun sequencing inhabiting fluid-filled fractures in the Deep approach, we identified a near-complete archaeal Mine Microbial Observatory (DeMMO), metagenome assembled genome, Ca. Sedimenti South Dakota. Fracture fluids continuously methylvorans, belonging to the TACK super flowed through in situ colonization reactors phylum. Phylogenetic reconstruction supports filled with an array rocks and minerals as the placement of the genome in a new phylum, attatchment surfaces. These experiments were Candidatus Superiorarchaeaota, basal to the installed at depths of 244, 610 and 1,478 m Thaumarchaeaota. Genome coverage indicates for 2-8 months. 16s rRNA gene sequencing the Ca. S. methylvorans is present throughout and scanning electron microscopy revealed the core but increases with depth below 9 cm, diverse microbial communities and a variety of which corresponds with the sulfate methane biogenic precipitates. Experiments with rocks transition zone. Metabolic reconstruction and minerals enriched for dramatically different revealed a bacterial style methylotrophy which communities from fluids and from experiments has not been described in Archaea, and it may with inert substrates. These results suggest that be coupled to dissimilatory nitrate reduction. members of the biofilms may be using minerals Carbon fixation appears to occur via a modified as both a surface for attachment and a metabolic reductive pentose phosphate pathway using energy source. Specifically, manganese oxide a deeply branching Ribulose Bisphosphate appears to be a favorable substrate for members Carboxylase/Oxygenase (RuBisCO) that of the family Desulfobulbaceae and class phylogenetically clusters with type III-a Thermodesulfovibrionia. Further, our results methanogenic archaea. Ability to utilize provide insight into the lifestyles of candidate polysulfides was also identified. Together, taxa; i.e. consistent with observations from we have identified a novel biogeochemically other studies, members of candidate phylum important microorganism that has the potential Omnitrophica tend toward a planktonic lifestyle to couple carbon, nitrogen an nitrogen and at DeMMO. sulfur cycles.

15 Spatial and Temporal Variations Phosphorus Uptake in Constructed of Water Quality in a Eutrophic Wetlands for Possible Nutrient Freshwater Lake and Their Loading Mitigation orrelation to easonal lgal C S A 1Denny, Sarah E., 2Brinkman, Jacob, and 1Druschel, Gregory K. Blooms 1Indiana University Purdue University Indianapolis Department of Earth Science, Indianapolis, IN, 2Eagle Creek Park, City of Howard, Chase S.1*, Ogashawara, Igor1, Koltsiduo, Ioanna2, Druschel, Indianapolis, Indy Parks. Gregory K.1** 1Department of Earth Sciences, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA, [email protected]*; Phosphorus loading to freshwater lakes and [email protected] (**corresponding author), 2Department of reservoirs can result in impaired water quality, Biology, Indiana University Purdue University Indianapolis including formation of harmful and nuisance Eagle Creek Reservoir (ECR) is a eutrophic algal blooms. Eagle Creek Reservoir (ECR), freshwater lake located in central Indiana that a significant source of drinking water for experiences seasonal algal blooms producing Indianapolis, has a long history of algal blooms taste and odor compounds (T&O), chiefly due to excess nutrient input. Floating wetlands 2-methylisobornel (MIB) and geosmin. The have been installed as both an educational reservoir supplies~80% of Indianapolis’ resource for people to learn about nutrient drinking water and serves as an important cycling, and as a pilot study to investigate their recreational area. Water samples were impact on reservoir water quality. Sampling collected between April and September 2018 hydrophytes for total phosphorus using XRF from fourteen different locations across the to measure phosphorus cycling and uptake in reservoir to examine the spatial and temporal constructed floating wetlands will allow us to distribution of water quality, nutrient levels, determine the approximate mass of P sequestered and microorganisms. Samples were collected at in plant material to mitigate impacts of nutrient 0.5m depth, Phycocyanin/Chlorophyll data was loading on ECR water quality. collected simultaneously using remote sensing equipment, and additional subsamples were To understanding the effectiveness of prepared for genomic and taste & odor compound constructed wetlands on up-taking and cycling analysis. Initial sample analyses have shown phosphorus, sampling plant matter bi-weekly, that significant changes exist through both time drying biomass in an oven for approximately 5-6 and space, at multiple scales, for measures days, grinding the dried material into powder including soluble reactive phosphorus, total with a ball mill, pressing the powder into pellets phosphorus, total dissolved phosphorus, MIB with a hydraulic press, and lastly using X-Ray and geosmin concentrations, and Phycocyanin/ Fluorescence to measure phosphorus content. Chlorophyll concentrations. Triplicate samples Standards were also developed to calibrate the for single locations showed a maximum of 10- XRF for plant matter, a series dilution with my 15% variation, with more significant variability ground plant matter and silicon dioxide. Results spatially. The most significant changes were indicate significant P uptake in grasses over observable north to south along the long axis the course of the season, but placing sufficient of ECR, but also with pronounced changes numbers of floating wetlands in the reservoir for close (<1,000 ft.) sampling points. These to impact P loading may be impractical as a initial observations support the hypothesis mitigation strategy. that certain areas within the reservoir serve as initial hotspots of activity and that ECR is a fairly dynamic system that operates differently between the north and south basins.

16 Sulfurization pathways in modern Physiology and Protein-Level euxinic lakes: Exploring the key Proteorhodopsin Expression constraints for organo-sulfur and Patterns pyrite formation in Vibrio campbellii CAIM 519

Fotios Fouskas1*, William P. Gilhooly III1, Molly D. O’Beirne2, Gwendolyn Gallagher1, Jacob Waldbauer1 Josef P. Werne2, Alice Bosco-Santos1,3, Martin Kurek1, Gregory K. 1Department of the Geophysical Sciences, University of Chicago Druschel1 1Earth Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA; *[email protected], [email protected], Proteorhodopsin, a light activated proton pump, [email protected], [email protected], 2Geology & Environmental has garnered attention for its apparent prevalence Science, University of Pittsburgh, Pittsburgh, PA, USA; mdobeirne@ in a wide variety of both environments and taxa pitt.edu, [email protected], 3Geology and Natural Resources, University of Campinas, Campinas, São Paulo, Brazil; [email protected] [1]. PR, a form of anoxygenic phototrophy, generates a proton gradient that microbes can Modern euxinic lakes are ideal settings for potentially use for ATP synthesis, flagellar studying the two competitive sulfurization movement, or nutrient transport, but its pathways that lead to pyrite and organo-S physiological role in marine microbes and its compounds (OSCs) formation by means of S contribution to the overall energy budget of isotopes. Mahoney Lake, Canada and Green marine microbial communities is not yet clear. Lake, NY, contain productive communities Previously, environmental PR abundance has of purple S bacteria and sulfate-reducers. been estimated using metagenomics [2,3] and 2- retinal concentrations [4], but not yet using The variability in the levels of SO4 , H2S and organic matter (OM) between the two lakes proteomics. can help elucidate factors that influence these sulfurization reactions. Within the Mahoney Here we quantify protein-level PR expression Lake sediments, the δ34S of pyrite and total using mass spectrometry-based proteomics. We organic sulfur (TOS) decrease with depth, developed new techniques for extracting PR, supporting no diagenetic effects. The isotope a hydrophobic integral protein, and quantified offset between pyrite and TOS also changes it using in vitro isotopic peptide labeling. downcore from ~15‰ down to nearly zero. In Growth of Vibrio campbellii CAIM 519, a PR- contrast, the corresponding δ34S values within containing microbe, was monitored under a the surface sediments of Green Lake increase range of carbon, nitrogen, and light conditions, downcore with a relatively constant offset. We including single carbon sources and varying suggest thus that the hyper-euxinic environment concentrations of Marine Broth. The purpose of Mahoney Lake has changed through time of this work was to identify the expression including changes in the Fe availability, the patterns of PR in an environmentally relevant nature of OM and therefore, the relative kinetic microbe in order to determine if and to what rates between pyrite and OSCs formation. extent PR is used as a survival mechanism to Kinetic modeling will evaluate the dominating generate energy under starvation stress.

pathway by varying Corg, H2S, S8, and Fe. Initial results show that only significant levels of [1] Rusch, D. B. et al. (2007) PLoS Biol. 5, 0398–0431 [2] Sabehi, G. et al (2005) PLoS labile Corg can trigger OM sulfurization rates in levels similar to those of pyritization which Biol. 3. [3] Venter, J. C. et al. (2004) Science could support a zero isotopic offset between 304, 66–74. [4] Gómez-Consarnau, L. et al. pyrite and TOS. FT-ICR-MS analysis of DOM (2017) bioRxiv 231167. doi:10.1101/231167 in Mahoney water column revealed abundant OSCs suggesting that rapid sulfurization of OM can occur syngenetically. 17 Using Reactive Iron Distribution to Molecular geochemistry of Characterize Redox Conditions in molybdenum-organic matter the late-Holocene record of Martin interactions in black shales ake L , USA Stephan R. Hlohowskyj1, Omid H. Ardakani2, Anthony Chappaz1 1Dept. of Earth and Atmospheric Sciences, Central Michigan Alyssa Henke1, William Gilhooly III2, Broxton Bird3 University, MI, USA, [email protected], 2Natural Resources 1,2,3 Department of Earth Sciences, Indiana University Purdue Canada, Geological Survey of Canada, Calgary, AB, Canada University Indianapolis

Iron geochemistry, specifically Fe-based Molybdenum (Mo) has been used as a paleo-redox proxies, have widely been used as the key proxy to identify sedimentary environments approach to assess local oxygen conditions in deposited under sulfidic conditions (i.e. ancient marine environments; to our knowledge euxinia). Initial research into Mo geochemistry these Fe-based proxies have not been applied lead the geochemical community to conclude to lacustrine water columns. Like marine that in sulfidic systems, Mo was generally basins, lakes experience fluctuations in oxygen dominated by iron sulfide mineral interactions availability, which is why we propose the which contributed the main burial pathway of implementation in Fe-based proxies in lacustrine Mo into sediments. More recently experimental environments, such as our study site, Martin approaches have shown Mo to strongly Lake. Martin Lake is a kettle lake in LaGrange interact with organic matter demonstrating an County, Indiana. Despite its hydraulically open increasingly important pathway for Mo in both conditions, Martin Lake remains seasonally oxic and anoxic settings. Here, we examined the stratified from April through November, which organic rich black shales of the Late Devonian causes bottom water anoxia from March Bakken formation to explore the molecular through December. A regional 2100 year-long geochemistry (e.g., in situ chemical speciation) precipitation reconstruction has already been of Mo in relation to organic matter at m created, from a multi-proxy study of Martin resolution. Our preliminary results confirm that Lake. New research focusing on geochemical Mo is often found in association with organic proxies, will help bridge the gap between matter phases, and that low temperature (100- the climate and its effect on the geochemical 200 ºC) hydrothermal alteration can modify the processes within the lake. I hypothesize Martin original Mo speciation. These new insights have Lake became oxic during time periods of low important implications for the interpretation water levels and anoxic when water levels were of the Mo paleo proxy records and emphasize higher. Times of increased precipitation will the need for including molecular geochemical show up in the record as an enrichment in the analysis to improve our understanding of how 13C and an increase in anoxia, due to stable redox conditions fluctuated in ancient systems. bottom water and prolonged seasonal thermal stratification, caused by the overall increase in depth. During extreme drought periods, the shallow water will allow for complete mixing and should remain oxic.

18 Understanding Microbial Evaluating proxies of microbial Contributions to Pyrrhotite carbon and sulfur cycling in methane Oxidation at Circumneutral pH seep sediments

Kathryn K. Hobart1,2, Daniel S. Jones1,3, Joshua M. Feinberg1,2 J. Houghton1, P. Willis2, D. Yang3, K. Dawson4, V. Orphan5, D. Fike1 1Dept. of Earth Sciences, University of Minnesota, Minneapolis MN; 1Washington University, St. Louis, MO; 2Westminster Christian 2Institute for Rock Magnetism, Dept. of Earth Sciences, University of Academy, St. Louis, MO; 3Francis Howell High School, St. Louis, Minnesota, Minneapolis MN; 3BioTechnology Institute, University of MO; 4Rutgers University, New Brunswick, NJ; 5California Institute of Minnesota, Saint Paul MN Technology, Pasadena, CA

The dissolution of sulfide minerals, particularly The effect of environmental conditions on pyrite and pyrrhotite, results in the production of microbial activity is complex and can lead to acidic water high in concentrations of dissolved non-unique or apparently inconsistent chemical metals and sulfate. Microorganisms accelerate records. Here, we evaluate several sedimentary dissolution of sulfide minerals in acidic systems, proxies with corresponding porewater chemistry but less is known about their impact at near-neutral from active methane seeps in Santa Monica pH. Pyrrhotite (Fe S, 0 ≤ x ≤ 0.125) is the second- 1-x Basin (water depth ~820 m). Porewater profiles most-abundant iron sulfide in the earth’s crust, and dissolves 10-100 times faster than pyrite under in the top 10 cm are consistent with high fluxes equivalent conditions. Understanding its dissolution of biogenic methane supporting elevated activity is critical to maintaining water quality standards in of anaerobic methane oxidation consortia that regions with active and historical mining. Microbial lead to [DIC] 10x higher than seawater with 13 isolates and communities substantially accelerate d CDIC < -50‰, and corresponding complete 13 pyrrhotite dissolution under circumneutral consumption of seawater SO4. Sediment d CTOC conditions as compared to abiotic controls. Six is relatively invariant (-25‰), with relatively strains of sulfur-oxidizing bacteria isolated from constant [TOC] of 4-6 wt% and C:N ratios of waste rock piles and humidity cells and an enrichment 8-9, consistent with a typical marine source community containing iron- and sulfur-oxidizers and little evidence for methanotrophy. In situ were used in batch experiments with a starting pH 34 d SH2S ranges from ~0 to +20‰, consistent of 4.5 and 6 where pyrrhotite was the only available with Rayleigh distillation, fast rates of sulfate electron donor. Measurements of aqueous sulfate, reduction (unlimited carbon supply) and a low aqueous iron (II), and bulk magnetic susceptibility were used to measure the dissolution of pyrrhotite apparent biological fractionation of ~20‰. 34 and accumulation of secondary iron phases. The In contrast, d SCRS is variable but much for presence of surface-attached bacteria appears to negative, typically from -30 to -10‰. Values 34 34 alter the formation or adhesion of passivation layers of d Sorg are closer to present day d SH2S but on the pyrrhotite grain surface. The figure below closely track the depth pattern of CRS with shows sulfate release versus time for an abiotic an offset ~+20‰. Sediment proxies suggest control (●), a sulfur-oxidizing isolate (▲), and an open system sulfur cycling at relatively slow enrichment (□) at starting pH 4.5. sulfate reduction rates with a relatively high apparent biological fractionation of ~45‰. These inconsistencies could be explained by Fe limitation, resulting in near instantaneous

capture of H2S as pyrite but continued growth

and equilibration of Sorg after burial.

19 Developing and utilizing a novel Mercury methylation and cadmium-specific fluorescent probe methylating communities in sulfate- technique to test the component impacted freshwater ecosystems additivity approach to surface Daniel S. Jones1,2, Nathan W. Johnson3, Carl P.J. Mitchell4, Gabriel M. complexation modeling Walker2, Jill K. Coleman Wasik5, Maisie Lenards2, Edward B. Swain6, Jake V. Bailey2 Clayton R. Johnson1, Joshua D. Shrout1, Jeremy B. Fein1 1University of Minnesota, BioTechnology Institute, St. Paul, MN, 1University of Notre Dame, Notre Dame, IN 46556, USA 2Dept. of Earth Sciences, University of Minnesota, Minneapolis, MN, USA, 3Dept. of Civil Engineering, University of Minnesota Duluth, The component additivity (CA) approach to Duluth, MN, USA, 4Department of Physical and Environmental Sciences, University of Toronto – Scarborough, Toronto, Ontario, surface complexation modeling (SCM) is a Canada, 5Department of Plant and Earth Science, University of method commonly used to predict the extent Wisconsin River Falls, River Falls, WI, USA, 6Minnesota Pollution Control Agency, St Paul, MN of metal adsorption in multi-sorbent systems containing bacteria. Quantitative tests of the Methylmercury (MeHg) is a bioaccumulative neurotoxin CA approach are rare because it is difficult to that is produced by certain sulfate reducers and other quantify bacterial metal adsorption, and thus anaerobic microorganisms. We are using an integrative geochemical and molecular approach to study the determine metal distribution, in multi-sorbent relationship between microbial community composition systems. In order to test the CA approach, we and methylation potential in sulfate-impacted freshwater develop a novel fluorescent probe technique sediments on Minnesota’s Iron Range. First, we performed which allows us to quantify the concentration a detailed characterization of methylating communities in two sulfate-impacted lakes using metagenomics, rRNA of Cd that is adsorbed to a bacterial population methods, and hgcA sequencing. Then, we extended our in fully hydrated samples. We conduct an results to a larger number of samples by combining extensive suite of control tests that verify that methylation rate measurements with hgcAB sequencing our treatment does not affect the extent of across a sulfate gradient in experimental wetland Cd sorption, that the measured fluorescence sediment mesocosms. Methylation rates and MeHg accumulation were response can be correlated to the concentration not clearly related to sulfate concentration or sulfide of Cd that is adsorbed to a bacterial cell accumulation in either the lakes or the sulfate-amended population, and that the technique can be used mesocosm sediments. In the lakes, hgcA gene sequencing to quantify Cd distribution in simple multi- and metagenomics showed that methylating communities sorbent samples. This study uses our technique differ among the sites, and that the most abundant methylating organisms were from taxa not previously to quantify bacterial Cd adsorption and Cd associated with MeHg production or hgcAB genes. distribution in mixed bacteria-mineral samples. We will describe metabolic capabilities of these novel We compare measured Cd distributions to CA potential methylators based on genome reconstruction predictions in order to test the CA approach. Our from metagenomic datasets, including improved binning and genome recovery of the most abundant hgcAB+ findings show that the CA predictions generally populations by combining long-read PacBio sequencing agree, within uncertainties, with the measured with short-read Illumina datasets. In the sulfate-amended Cd distributions in all systems studied. Our mesocosm sediments, methylmercury production results demonstrate that the Cd-fluorescent rates varied over two orders of magnitude across the probe technique is a suitable, and relatively experiment but did not show a clear relationship with the level of sulfate amendment. In general, differences simple, option for quantitatively testing CA among microbial communities trended with the sulfate surface complexation models. gradient. We will describe the composition of methylating communities based on hgcAB amplicon sequencing from across the experiment, and relate hgcAB libraries to rates of mercury methylation and sulfate amendment. Our results show that previously unrecognized methylating populations are abundant and may be important for MeHg production, and expand our knowledge of the clades and environmental factors that affect MeHg production in sulfate-impacted freshwater ecosystems. 20 Assessment of Microbial Community Rates and Products of Fe(II) Composition in Eagle Creek Oxidation in Trioctahedral Reservoir using 16S Next Generation Smectites equencing and q S PCR Robert J. Kupper1*, Jeffrey G. Catalano1 1Earth and Planetary Sciences, Washington University, St. Louis, MO Ioanna Koltsidou1, Christine J. Picard1, Gregory K. Druschel2 1Department of Biology, Indiana University Purdue University, 63130, USA. (*[email protected]) Indianapolis, IN, USA, 2Department of Earth Sciences, Indiana University-Purdue University, Indianapolis, IN, USA Trioctahedral Fe(II) smectites form during the anoxic alteration of basalts, are common in the The presence of taste and odor (T&O) modern subsurface oceanic crust, and likely compounds, especially the odorous bacterial occur on Mars. Before Earth’s oxygenation, metabolites 2-methylisoborneol and geosmin these clays would have been exposed on the (trans-1,10 dimethyl-trans-9-decalol), is a global ocean floor. On modern Earth, however, they problem impacting freshwater quality. Eagle rapidly oxidize upon exposure to air. Due to Creek Reservoir in Central Indiana supplies the difficulty in sampling and preserving these approximately 80% of Indianapolis’ drinking clays, their role in the biogeochemical iron water and experiences odor problems frequently. cycle remains poorly understood, including In order to get critical insights into the origins of their availability as an electron donor to Fe- odor episodes, 16S rRNA genomic sequencing, oxidizing microorganisms. has been used in conjunction with measurements of MIB and geosmin concentrations. Samples Fe(II) smectites were synthesized spanning were collected at various locations of ECR from the compositional range observed in altered May to August of 2017 and filtered through a basalts. Powder XRD confirmed these to be Sterivex filter unit. DNA was extracted using the trioctahedral, turbostratic 2:1 phyllosilicates. DNeasy PowerWater Sterivex kit by Qiagen and The oxidation of Fe(II) in these clays was 12 representative samples were selected for 16S measured during exposure to dissolved O2 sequencing and OTU clustering analysis was or nitrite, an intermediate produced during performed using the CLC Genomic Workbench denitrification known to abiotically oxidize software. MIB and geosmin concentrations dissolved Fe(II). Oxidation in air-equilibrated from GC-MS analysis were provided by the suspensions (PO2 ≈ 0.2) was incomplete Citizens Energy Group lab. Clustering analysis but proceeded more rapidly and to a greater of the 16S rRNA gene revealed that the relative extent in smectites containing more iron. No abundance of cyanobacteria in samples followed oxidation was detectable in samples exposed the pattern of ΜΙΒ and geosmin fluctuation, to nitrite (as 5 mM NaNO2) compared to ranging from 5% at low concentrations up to oxidant-free controls. Under microaerophilic 83% at high concentrations. Actinobacterial conditions (PO2 = 0.02) oxidation proceeded at relative abundance was significantly lower than a slower rate than in air equilibrated samples. cyanobacteria in every sample, ranging from XRD patterns of products did not indicate the 3% up to 14%. Additionally, these analyses formation of any new minerals during oxidation indicated synechococcus and pseudanabaena as the dominant cyanobacterial genera. Future work aims to utilize these results to develop environment-specific qPCR primers to target geosmin production as a tool in predicting and preventing taste and odor episodes.

21 Understanding organic phosphorus Metagenomic analysis of a novel cycling in redox-dynamic eutrophic potential mercury-methylating freshwater systems population from a hypereutrophic, sulfidic lake Kurek, Martin R.1, Harir, Mourad2, Shulke, John1, Leduc, Meagan3, Schroth, Andrew3, Schmitt-Kopplin, Phillipe2, Druschel, Gregory K.1 Maisie Lenards1, Jake V. Bailey1, Daniel S. Jones1,2 1 Indiana University Purdue University Indianapolis, Department 1University of Minnesota, Dept. of Earth Sciences, Minneapolis, MN, of Earth Science, [email protected], 2 Helmholtz Zentrum USA, 2University of Minnesota, BioTechnology Institute, St. Paul, MN München, Deutsches Forschungszentrum fur Gesundheit und Umwelt, [email protected], 3 University of Vermont, Department of Geology Methylmercury is a bioaccumulative neurotoxin that is produced by certain anaerobic microorganisms. Organic phosphorus represent a significant While sulfate-reducing microorganisms are thought fraction of phosphorus species in freshwater to be the primary mercury methylators in most lakes and are mobilized via changing redox environments, other anaerobes including iron conditions at the sediment-water interface reducers, methanogens, and other organotrophs largely by interactions with iron. Fourier are also known to methylate mercury. In a recent transform ion cyclotron resonance mass metagenomic analysis of two sulfate-impacted spectrometry (FTICR-MS) is a powerful lakes on Minnesota’s Mesabi Iron Range, Jones analytical technique that can measure molecular et al. (in review) identified diverse populations masses with remarkable precision, yielding with the capability to methylate mercury, many a look at thousands of different molecules of which represent phyla not previously known to have genes for mercury methylation (hgcAB). By in a single sample. This technique has been combining a short-insert (3-8 Kbp) PacBio library optimized for characterizing unique organic with the existing Illumina HiSeq metagenomes, we molecular signatures of dissolved organic matter improved genome recovery of the most abundant (DOM). Water and sediment samples were hgcAB+ bins representing one of the lakes. The collected from eutrophic Missisquoi Bay in Lake population represented by this bin, which contains Champlain to assess how biogeochemical redox a close relative or member of the “Aminicenantes” cycling links to organic phosphorus mobility (formerly Candidate Phylum OP8), was 2-7% and bioavailability for cyanobacterial blooms. of the community in the anoxic sediments and The focus of this study was to investigate how anoxic/microoxic water column. The bin contains dissolved organic phosphorus (DOP) is cycled respiratory cytochromes, including high-affinity within the water column and seasonally. This terminal oxygenases and tetrathionate and thiosulfate was achieved by comparing the molecular reductases, indicating that the Aminicenantes-like signatures of DOP in the mass spectra to the bulk population may reduce or detoxify oxygen and molecular signatures of DOM, which follow a respire some inorganic sulfur compounds. It does predictable, gaussian distribution. Variations not, however, appear to be able to respire sulfate. It in the heteroatomic distribution between DOM has a complete glycolysis parthway and TCA cycle, and encodes diverse fermentation capabilities, and DOP were seen in the water column, and an electron bifurcating NADH dehydrogenase/ between different seasons indicating a shift heterodisulfide reductase (hdrCBA-flxABCD), from terrestrial to microbially processed DOM. and genes for flagella synthesis and chemotaxis. Quantitative measurements such as chlorophyll The Aminicenantes-like population appears to a and dissolved oxygen in the water column be an organoheterotroph capable of anaerobic or corresponded to qualitative changes in the microaerophilic growth, and makes its living by molecular diversity of DOP and DOM, driven degrading organic carbon from the algal biomass by biotic and abiotic processes. that is ubiquitous in its hypereutrophic environment. by degrading organic carbon from the algal biomass that is ubiquitous in its hypereutrophic environment.

22 Sequencing read distribution in A new global synthesis of bacterial genomes with and without sedimentary leaf wax isotopes: GC skew expanding to include the Arctic

Barbara J. MacGregor1, Manuel Kleiner2 Jamie M. McFarlin1, Yarrow Axford1, Andrew Masterson1, 1University of Minnesota, Minneapolis MN, 2North Carolina State Magdalena R. Osburn1 University, Raleigh NC 1Northwestern University, Evanston, IL.

The large sulfur bacteria (LSB) include species of The hydrogen isotopic composition (d2H) varied morphology, and some of the largest known of plant wax C28 n-alkanoic acids and C29 bacteria. Possible key events in LSB evolution n-alkanes correlate strongly with the d2H values include loss of canonical genes for septum formation of mean annual precipitation in middle and and replication initiation. There are parallels in the low latitudes (Sachse et al, 2012). However, Cyanobacteria, with which the LSB appear to have 2 a history of gene exchange. We previously showed systematic examination of the d H values of that some members of each group lack the GC skew sedimentary plant waxes in the high latitudes, seen in many circular microbial genomes; skew is and compilation of other chain-lengths on a the preponderance of G over C in the leading strand, global scale, was heretofore limited. Here, we with the two origin-to-terminator segments skewed present new data on the d2H and d13C values in opposite senses. of sedimentary n-alkanes and n-alkanoic acids Genes near the origin of circular replicons are from a modern transect covering northwest expected to be at higher copy number in actively to southernmost Greenland in the context of dividing cells; given an artifact-free protocol, this global sedimentary wax data. We show a strong could correlate with the distribution of sequencing relationship between the d2H values of long- reads around the chromosome. We have undertaken chain n-alkanes and n-alkanoic acids to d2H of a look at sequencing read distributions in public precipitation, and discuss apparent limitations cyanobacterial genomes. The first results are intriguing: reads were evenly distributed around in using these compounds interchangeably as the genome of Synechococcus WH8103, which a paleoclimate proxy. We also present data that 2 exhibits strong skew, but varied over several orders cautions against interpreting d H values of mid- of magnitude for different regions of the unskewed chain n-alkanes and n-alkanoic acids as records Calothrix 336/3 genome. Calothrix has numerous of lake water isotopes. We argue that seasonality annotated transposases, suggesting a genome of plant growth exhibits strong influence on the rearrangment mechanism. But what accounts for 2H values of plant waxes in the Arctic, with a the read number differences? If gene copy numbers bias towards utilization of summer water during do differ widely, how are gene expression and wax synthesis in Greenland. We argue that chromosomal division regulated? If not, what apparent fractionation corrections in the Arctic accounts for the differences? Analysis of additional need to consider the season of precipitation genomes may shed some light. utilized during plant growth, but otherwise find that sedimentary long-chain n-alkanes serve as a robust proxy for precipitation d2H values globally. This finding opens the door to widespread utilization of this proxy in Arctic reconstructions, where records of hydroclimate during past warm periods are urgently needed to contextualize ongoing climate change.

23 The deep biosphere in the jungle: Novel Metaproteomic Approaches following carbon in serpentinizing Applied to Arctic Soils Reveal springs in a tropical surface biome Niche Partitioning of Microbial iogeochemical unctions and D’Arcy Meyer-Dombard1, Dawn Cardace2, Magdelena Osburn3 B F 1University of Illinois, Chicago IL, 2University of Rhode Island, Systematic Variations with 3 Kingston RI, Northwestern University, Evanston IL Vegetation Type

The low DIC and high CH4 and H2 gas Samuel Miller and Jacob Waldbauer concentrations of serpentinizing ecosystems University of Chicago, Department of the Geophysical have led to interest in H2 based metabolisms Sciences in these subsurface biomes. However, a true Increasing plant biomass and the spread of large subsurface signature can be difficult to identify woody shrubs across the Arctic have accompanied in surface expressions such as serpentinizing warmer temperatures and permafrost thaw. We springs. Here, we explore carbon resources in used novel metaproteomic methods to study the serpentinizing springs in the tropical climate effect of floral type on soil microbial metabolism of the Zambales and Palawan ophiolites and biogeochemical cycles. Our computational in the Philippines, with a focus on surface approach greatly boosts protein identification in environmental samples and associates homologous vs. subsurface processes and exogenous vs proteins with metagenome-assembled genomes, endogenous C input. Isotopic signatures in enabling determination of the strength of protein fluids, biomass, and carbonates were examined expression by different clades. to identify sources and sinks of C, carbonate We applied these methods to tussock, intertussock, geochemistry, and the effect of seasonal and shrub soils collected from the area of Toolik precipitation. Precipitation affected δ13CDIC Lake, Alaska. Thousands of different proteins, 13 chiefly bacterial, were identified in the soils. The and δ CDOC, which reflected seasonal gain/ functional profiles of organic soils cluster by plant loss of atmospheric influence and changes in type, whereas mineral soils cluster separately exogenous DOC input. The primary C source regardless of plant type, indicating that a similar in high flow systems was variable, with DOC set of processes occurs in mineral soils and distinct contributing to biomass in most springs, and sets of processes influenced by plant inputs occur a mix of DIC and carbonates contributing to in organic soils. Clustering by plant type is due to differences in the abundances of multiple microbial biomass in select locations. However, primary protein functions rather than the presence or absence C resources in low flow systems may depend of a few key functions. When broken down by more on endogenous than exogenous C, even in clade, protein functional profiles shift in the same high precipitation seasons. Carbonate formation direction, reflecting consistent changes in the relative occurred as a mixture of recrystallization/ abundances of proteins between environments rather recycling of older carbonates and rapid than changes in the propensity of clades to express 13 18 different proteins. precipitation, with highly δ C and δ O depleted We found significant niche partitioning between carbonates. Subsurface signatures were most bacterial clades with regard to carbon substrate apparent in the driest seasons and lowest flow and nutrient utilization. Separate bacterial groups systems, indicating locations where metabolic dominate the degradation of cellulose, hemicellulose, processes divorced from surface influences are simple sugars and C1 compounds. Amino acid most likely to be occurring. transporters are much more abundant than proteins involved in N2 fixation and the utilization of urea, - - polyamines, NH3, and NO3 /NO2 . The dominance of amino acid uptake by Rhizobiales may indicate the flow of N between this frequently mutualistic group and plants. Clades are also differentiated by mechanisms of C/nutrient storage, trace element acquisition, motility, and adhesion. 24 Exploring the “microbial dark Constructing methane-supplemented matter” through large-scale foodwebs using carbon isotope genomics analysis of aquatic invertebrate remains in North American lake 1 2 1,3 Senthil K Murugapiran , Jeff R Havig , Trinity L Hamilton sediments 1Department of Plant & Microbial Biology, College of Biological Sciences, University of Minnesota Twin Cities, MN 55108, Jaclyn Oliver1, Jacob J. Meldrum1, Benjamin K. Harrison1, Maarten 2Department of Earth Sciences, Newton Horace Winchell School of van Hardenbroek2, Megan Rohrssen1 Earth Sciences, University of Minnesota Twin Cities, MN 55455, 3The 1Department of Earth and Atmospheric Sciences, Central Michigan BioTechnology Institute, University of Minnesota Twin Cities, MN University, Mount Pleasant, MI, 48859, USA., 2School of Geography, 55108 Politics and Sociology, Newcastle University, Newcastle NE1 7RU, UK We use next generation, large-scale `omics’ Daphnia and Chironomidae consume diverse approaches in combination with traditional microbiology, ultra-high resolution geochemical food sources including algae, terrestrial detritus, and geological data to understand the functions, and methane-oxidizing bacteria. Daphnia interactions of microbes in natural and engineered resting egg cases (ephippia) and chironomid systems, how they respond and adapt to `fringe’ larval head capsules are made of chitinous environments -- extreme variations including material that retains its carbon isotopic redox gradients and temperature. Many of the composition after deposition in lake sediments. microbes that we study are recalcitrant to laboratory Because these food sources can have distinctive cultivation. Moreover, the complete genome carbon isotopic compositions, the delta13C sequences of these microbes are not available in any sequence databases. Due to the paucity of values of ephippia and head capsules reflect information about these unknown, yet abundant and the importance of methane-derived carbon their important microbes, they are sometimes referred to diet (e.g. Bastviken et al., 2003). We predict as `microbial dark matter’. These microbes offer that, as has been shown in a European lake clues to understand the origin and evolution of life (Schilder et al., 2017), methane will be more on earth and possibly other planets. We therefore use important in the food webs of Midwestern lakes cultivation-independent methods such as genomics, with abundant nutrients from runoff, whereas metagenomics, 16S rRNA analysis to identify and methane may be a less important carbon source characterize the microbial communities in these in waters that are not as eutrophic. fringe environments. Computing facilities provided by the Minnesota Supercomputing Institute (MSI) To test our hypothesis, we will collect play a critical role in our bioinformatics pipeline sediment cores from lakes near Central in all stages of data analyses including: quality Michigan University and analyze the carbon filtering; assembly; annotation; phylogenomics; isotopic compositions of Daphnia ephippia methods to accurately estimate the completeness of and chironomid head capsules. In order to see genomes; metagenomic binning using nucleotide whether there is a clear relationship between identity and tetranucleotide frequency; customized methane in the water and in the invertebrates BLASTP and hmmer searches to predict metabolic (Schilder et al., 2015), we will also need to capacity; analyzing tandem mass spectrometry metaproteomics data; metatranscriptomics measure methane concentrations in lake water, data analysis; submitting metagenomes, isolate accounting for seasonal variability in methane genomes, 16S rRNA metadata and sequences to concentration and ephippium production. appropriate NCBI sequence databases. Using some With this information we can relate the carbon of the analyses from our lab research, I will present isotopic compositions of the remains to methane how a robust, well organized and documented, concentrations. user-friendly computing environment such as MSI Bastviken, D. et al., (2003) Ecology, 84: 969- enables our lab to carry out data crunching in a 981.; Schilder, J., et al., (2015) Limno. and highly reliable, reproducible and replicable manner --- some of the most important characteristics for Oceano research in the era of `big data’. 25 Effects of Fe(III) inputs on the Isotopic disequilibrium in Prosopis rate of methanogenesis in wetland tree cellulose as an indicator of sediment microcosms water stress and hydroclimate variability Theodore Flynn1, Lauren Johnson1, Zena Jensvold1, Maxim Boyanov1,2, Kenneth Kemner1, Edward O’Loughlin1 Elizabeth Olson, Justin Dodd 1Argonne National Laboratory, Argonne, IL, 2Affiliation, location, 1Northern Illinois University, Dekalb, IL 3Bulgarian Academy of Sciences, Sofia, Bulgaria

Sulfate and Fe(III) have been shown to Isotope dendroclimatology has the potential inhibit methanogenesis in transiently anoxic to provide quantitative proxies of past environments. This has been ascribed primarily hydroclimate, yet efforts are limited by the to the ability of sulfate and Fe reducers to variable physiological response of trees to outcompete methanogens for electron donors. environmental change. Prosopis sp. are endemic The perceived role of competitive inhibition in to the hyper-arid core of the Atacama Desert limiting methanogenesis, however, is largely in northern Chile; where in the absence of based on experiments where methanogenesis precipitation these trees use only groundwater. was inhibited in microcosms that had Fe(III) or Tree-rings in stems and branches differ for sulfate present at the onset. In dynamic redox all three isotopes (∂13C, ∂2H, ∂18O). Branch environments, the formation of Fe(III) is often cellulose values were lower than stem values on controlled by episodic influxes of oxygen into average, with a difference of 0.4 ‰ for ∂18O, reduced sediments, so the impact of Fe oxide 0.7‰ for ∂13C and 6.0 ‰ for ∂2H. These addition on active methanogenic communities differences likely reflect the different proportion is unclear. We conducted experiments using of stored versus current photosynthate used sediment from a freshwater wetland amended during cellulose synthesis in stems and branches. with acetate. Shortly after the onset of Prosopis sp. trees respond to drought stress by methanogenesis, we amended each microcosm shedding biomass (e.g. leaves and branches). with either ferrihydrite, lepidocrocite, or This physiological adaptation to extreme aridity goethite. Methanogenesis declined dramatically provides a mechanism by which the proportion following the addition of Fe oxide, with greater of current photosynthate decreases in response inhibition of methanogenesis observed with to decreasing water availability (i.e. lowering ferrihydrite and lepidocrocite relative to goethite. of the water table). The significant correlation Unamended microcosms were dominated by between variations in the ∂18O and ∂2H values Methanomicrobia, a class of methanogenic in branches and changes in groundwater depth ( archaea that comprised 32% of the community r = 0.42; p < 0.0001) is evidence for the impact during peak methane production. In Fe-amended of biomass shedding on photosynthate source . microcosms these same taxa were initially This study demonstrates that Prosopis sp. branch ~10% of the community prior to the addition of cellulose are more sensitive to changes in GWD ferric minerals, but Geobacter dominated soon than stem cellulose, which has implications for thereafter. Our results suggest that the impact of the use and comparison of different plant tissue ferric oxides on methanogenesis is due to more types in paleoclimate reconstructions. than just thermodynamic limitations or kinetic inhibition.

26 Ediacaran oxygen oases and the Compositional and metabolic emergence of bilaterian burrowing differences in nitrifying communities across the aurentian reat akes Stephanie Olson1, Mary Droser2, Timothy Lyons2 L G L 1University of Chicago, 2University of California, Riverside Justin C Podowski1, Sara F Paver1, Ryan J Newton2, Maureen L Coleman1 Helminthoidichnites is the most abundant 1University of Chicago, Chicago, Il,2University of Wisconsin- Ediacaran trace fossil. At a glance, Milwaukee, Milwaukee, WI Helminthoidichnites appears to be a leveed The Laurentian Great Lakes hold 21% of furrow that traces the horizontal movements of Earth’s freshwater, and their shores are home a small bilaterian animal across the seafloor, but to more than 30 million people. Despite the it is also frequently preserved in negative relief importance of this ecosystem, the composition on the bottom thin, laterally discontinuous and dynamics of microbial communities in the beds. This preservation style requires that Great Lakes remain poorly characterized. Here the animal burrowed beneath the margins of we describe genome diversity of water column these discontinuous sediments---and was thus microorganisms, from our ongoing Great among the first in Earth history to penetrate the Lakes Microbial Time Series. We find that sediment-water interface, albeit horizontally both abundance and composition of nitrifying rather than vertically. Yet the motivation for this communities differ across the Great Lakes, energy-intensive behavior is unclear. We probe most strikingly between oligotrophic Lake this enigmatic behavior. We examine the spatial Superior and eutrophic Lake Erie. Ammonia distribution of bed sole Helminthoidichnites oxidizing archaea appear in the deepest in negative relief at Nilpena (Flinders Ranges, waters of Michigan, Ontario and Superior, but South Australia) and we interpret our results ammonia oxidizing bacteria are also abundant in the context of a simple model for benthic and widespread. Genome reconstruction further oxygen diffusion in sandy sediments influenced sheds light on the novelty of nitrifying microbes by microbial mats, which were ubiquitous in in the Laurentian Great Lakes, recovering the Ediacaran marine environment. We find the dominant nitrite oxidizing taxa in Lake that the margins of discontinuous sands likely Erie, which are closely related to Candidatus hosted oxygen levels in significant excess Nitrotoga. Analysis of recovered Nitrosospira of ambient seawater---potentially enticing genomes reveals a distinct group that contains the bilaterian responsible for producing the the light activated proton pump proteorhodopsin, Helminthoidichnites trace to engage in early a first for any ammonia oxidizing organism. burrowing behaviors prior to the advent of Together, these results suggest that rates and modern-style burrowing and large-scale mixing controls on nitrification across the Laurentian of sediments in the Phanerozoic. These results Great Lakes are likely very different, owing in imply an important role for oxygen in the tempo part to the diverse physiology and metabolism and mode of biological innovation on Earth, of the different microbes that dominate including the emergence of burrowing. nitrification across these lakes.

27 Assessing Microbial Community The source of sulfate in biogenic Assembly in a Serpentinization- calcite: insights from μ-XRF Influenced Aquifer over Time imagine, XANES spectroscopy and isotope studies of ancient and extant L.I. Putman1, M.D. Kubo2, W.J. Brazelton3, D. Cardace4, M.O. Schrenk1 brachiopods 1Michigan State University, East Lansing, MI 48824, 2SETI Institute & NASA Ames Research Center, Moffett Field, CA 94305, 3University Jocelyn A. Richardson1*, Matthew Newville2, Anthony Lanzirotti2, of Utah, Salt Lake City, UT 84112, 4University of Rhode Island, Samuel M. Webb3, Catherine V. Rose4, Jeffrey G. Catalano1 and David Kingston, RI 02881-0816. A. Fike1* 1Department of Earth & Planetary Sciences, Washington University, St. Louis, MO 63130 USA, 2Consortium for Advanced Radiation The Coast Range Ophiolite Microbial Sources University of Chicago Chicago, Illinois, 60637, U.S.A, Observatory (CROMO) is a series of wells 3Stanford Synchrotron Radiation Lightsource, Menlo Park, CA 94025, USA., 4 School of Geography and Geosciences, University of St. drilled into serpentinized soil and bedrock Andrews, Fife KY16 9ST, Scotland in Northern California, accessing high pH, moderately saline aquifers. Surface conditions Articulate brachiopods are accepted to be robust at CROMO are dynamic and are subject to archives for geochemical proxies due to their extreme seasonality in precipitation. Due to shell structure, comprised of a bi-layered low this, it is expected that substrate availability in Mg-calcite. Brachiopods frequently retain high the subsurface aquifers fluctuates throughout abundances of carbonate-associated sulfate the year and requires metabolic versatility from (CAS). This study aims to assess the reliability the resident microorganisms. This work aims to of CAS in brachiopods by determining the assess what processes of community assembly source of inorganic sulfate and role of organic are at play in this extreme environment, and sulfur species within the extant Terebratalia what geochemical and physical factors play a Transversa and fossil brachiopods by combining role in driving community assembly processes m-XRF imaging, XANES spectroscopy, SEM over time. Six years of geochemical and 16S imaging and isotope data. Fossil brachiopods rRNA gene sequence data were compiled show intra-specimen variability in sulfate for analysis. Preliminary results suggest that abundance, where sulfate varies along the community assembly is generally deterministic primary shell fabric. XANES spectroscopy in this system, indicating that it is driven by indicates that inorganic lattice bound sulfate is environmental conditions. Results also show the dominant S-species in fossil brachiopods, that assembly processes change over time and but low amounts of thiol and sulfoxide are seem to be affected by pH, salinity, and redox present. T. Transversa show a greater abundance conditions. Further analysis of this data will of, localized, thiol and sulfoxide and esters. inform upon environmental parameters that Sulfate abundance in T. Transversa also follows are driving microbial community assembly the primary fabric. SEM images indicate that and composition over time and in response to sulfate abundance increases towards the edge changes in the subsurface. Results from this work 34 of calcite crystals. Bulk rock δ SCAS of the will elucidate ecological processes resulting in samples containing the fossil brachiopods the observed communities within this extreme were consistently heavier than time-equivalent environment, and also have implications for 34 brachiopod-only values. In contrast, bulk δ SCAS better understanding microbial community of modern T. Transversa is 22.4‰, 1‰ heavier diversity and function in this system. than coeval seawater. Although variability exists in CAS in all brachiopods, the variability is muted compared to bulk rock data, and that brachiopods more accurately record seawater sulfate values. 28 Sediment trace metal contents do Microbes, Minerals and Electrodes not reflect porewater chemistry in a at the Sanford Underground low-oxygen Precambrian analogue Research Facility (SURF): lectrochemistry ft below the Kathryn I. Rico1, Nathan D. Sheldon1 E 4000 1Department of Earth and Environmental Science, University of surface Michigan, Ann Arbor, MI Annette Rowe1, Karla Abuyen2, Bonita Lam2, Brittany Kruger3, Caitlin Casar4, Magdalena Osburn3, Moh El-Naggar2, Jan Amend2 Sediment trace metal contents are regularly 1University of Cincinnati, Cincinnati, OH, 2University of Southern used to infer water column redox chemistry California, Los Angeles, CA, 3Desert Research Institute, Las Vegas, in the geologic record. Here, redox-sensitive NV, 4Northwestern University, Evanston, IL trace metal contents are measured across water Little is known about the importance of column, sediment, and porewater profiles of the mineral oxidation processes in subsurface Middle Island Sinkhole (MIS). MIS, located 23 environments. This stems, in part from our m beneath oxic Lake Huron, is a low-oxygen limited insight into the biochemistry of many of system with microbial mats that utilize various these metabolisms, especially for interactions phototrophic and heterotrophic metabolisms. with solid phases. To this aim, we have As such, it is a useful system for considering been developing electrochemical cultivation abiotic and biotic controls on trace metal techniques, to target enrichment and isolation cycling, and has been used as an analogue for of microbes capable of oxidative extracellular shallow shelf biogeochemistry in Proterozoic electron transfer (EET)—transfer of electrons oceans. Water column profiles show a stark from the exterior of the cell to the interior. Our increase in Fe from below detection near the previous worked focused on marine sediments; surface to over 100 ppb within the chemocline, using an electrode poised at a given redox whereas Mo and Zn profiles decrease from potential to isolate mineral oxidizing microbes. 538 to 390 ppt, and 81 to 56 ppb, respectively. At the Sanford Underground Research Facility Although changes in the water column profiles (SURF) in Leed, South Dakota, we have been are unidirectional with depth, samples taken utilizing similar electrocultivation techniques across the redoxcline (21–23 m depth) indicate to understand: 1) the potential for mineral fluctuating trace metal contents. Downcore (sulfur) oxidation by subsurface microbes, sediment Fe/Ti (9.1 ± 0.5 mol/mol) and Zn/ 2) their selective colonization on mineral vs. Ti (25.8 ± 2.5 umol/mol) profiles are relatively electrode surfaces, as well as 3) the community consistent, whereas sediment Mo/Ti is much composition of microbes capable of these more variable (40.1 ± 8.8 nmol/mol), possibly metabolic interactions. An electrochemical demonstrating its sensitivity to sulfide and/or and mineral enrichment scheme was designed the presence of methanogens in the sediments. and installed into a sulfidic groundwater flow, Inconsistent porewater profiles highlights the located at the 4100 ft level of the former gold need to address spatial and temporal variability mine. The communities enriched on electrodes when sampling aquatic environments and (graphite and indium tin oxide coated glass) challenges our understanding of sediment redox and minerals (gypsum, pyrite, and quartz) proxies in the geologic record. were compared to the long-term planktonic microbial community observed. Ultimately, these observations will help inform the potential activity of a lithotrophic microbes from a site where these metabolisms have been predicted from the geochemical data.

29 Biogeochemical transformations of Microbial contributions to the selenium by common saprotrophic sediment N and C isotopic record soil fungi Cody S. Sheik1 1Large Lakes Observatory, University of Minnesota Duluth, Duluth, Mary Sabuda1, Carla Rosenfeld2,3, Joshua Torgeson1, Cara Santelli1,3 MN 1Department of Earth Sciences, University of Minnesota, Minneapolis, MN, 2Argonne National Laboratory, Lemont, IL, 3BioTechnology Earth’s large lakes are unique aquatic Institute, University of Minnesota, Saint Paul, MN ecosystems, but we know little of the microbial Selenium (Se) plays a key role in human and life driving sedimentary biogeochemical cycles ecosystem health as it is an important trace and ultimately the isotopic record. Large lake element for most life yet is an element of sediments are biogeochemically active and increasing environmental concern due to its have oxygen consumption rates akin to pelagic toxicity in high concentrations. Interestingly, ocean sediments. Thus, large lakes provide fungi do not require Se for metabolic functions biogeochemical contrasts to highly productive yet some common soil fungi such as Alternaria freshwater and coastal marine systems. alternata and Paraconiothyrium sporulosum are Sediment cores from six stations across the capable of reducing Se from aqueous Se(IV/ western arm of Lake Superior were sampled. VI) to solid Se(0) and volatile Se(-II) in an Microbial community structure followed oxic environment. However, little is understood patterns in bulk sediment carbon and nitrogen about the chemical and/or genetic mechanism(s) concentrations. Observed patterns were loosely of these mycogenic Se transformations over driven by land proximity. Sediment carbon and time. Cultures of these fungi were grown with nitrogen isotopes correlated significantly with 0.1 and 0.5 mM selenite (Se(IV)) to track Se microbial community structure. However, 15N remaning in solution, solid-associated Se, and showed much stronger correlation than 13C, and calculate potentially volatilized organic Se became heavier with core depth. Coinciding with over 32 days. Results from this work indicate the increase in 15N values, we see evidence of Paraconiothyrium reduces ~0.16 µmoles Se/ both denitrification and anammox processes in day and Alternaria reduces ~0.90 µmoles Se/ metagenome assembled genomes. Abundance day. Geochemical speciation of aqueous and of these genomes also varies with depth biomass associated phases shows changes in suggesting these novel microorganisms are the proportions of inorganic and organic Se partitioning into specific sediment geochemical compounds with time. Transmission Electron zones. Additionally, several genomes are Microscopy images reveal intracellular Se involved in sulphur cycling, suggesting a dual consists of 50-200 nm electron diffraction biogeochemical role and cryptic sulfur cycling. amorphous particles in the cytoplasm and aligned Together, the pervasiveness of co-metabolic along the cell membrane. 25-50 nm Se particles pathways suggests interpretation of isotopic also aggregate into 200 nm clusters along the records may be messier than previously thought. periphery of the cells in a polymeric substance. Combined, this time-series experiment provides insight for discerning the mechanism(s) behind Se detoxification.

30 Phosphorous speciation and mobility Changes in Bacterial Growth in Missisquoi Bay mesocosms under Rate Lead to Hydrogen Isotope extended conditions of reduction, Fractionation oxidation and fluctuating oxidation , - Derek A. Smith1,*, William Leavitt2, Melanie Suess1, Alexander reduction Bradley1 1Deparment of Earth and Planetary Sciences, Washington University John Shulke1*, Martin Kurek1, Meagan Leduc2, Andrew Schroth2, in St. Louis, 2Department of Earth Sciences, Dartmouth College, Austin Wilkes2, Gregory K Druschel1 *Department of Biology, Case Western Reserve University 1 Department of Earth Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN USA, [email protected] (*presenting author), 2 Department of Geology, University of Vermont, The hydrogen isotopic fractionation of fatty Burlington, VT acids in lipid metabolism has been shown to be influenced by salinity, growth phase, and lipid Mobility of phosphorus (P) between sediments biosynthetic pathway, but all were believed to and water column in many freshwater lakes is be secondary to the central metabolism of the a process partially governed by the dynamic organism. This was further complicated when interaction of iron and P. Dynamic redox hydrogen isotope values were shown to vary conditions across the sediment-water interface across microbial strain, electron donor, and (SWI) have been linked to nutrient mobility electron acceptor. Theoretically growth rate and harmful algal blooms in a study site in could impact the extent of equilibration between Missisquoi Bay, a shallow, eutrophic bay the reservoirs of intracellular hydrogen, and the located at the northern end of Lake Champlain availability of NAD(P)H. Some research even (Smith et al., 2011). Additionally, mobility and suggested that growth rate might control the bioavailability of organic P species has been production of NAD(P)H. Other research has shown to behave differently from inorganic P shown that growth rate may be correlated to species (Giles et al., 2015). Defining the timing hydrogen fractionation of fatty acids in sulfate of the link between redox chemistry changes reducing bacteria and of alkenones in algae. across the SWI and nutrient mobility is needed However, inconsistent observations have led to assess how nutrient flux between sediment others to conclude that growth rate is not a and water column may be a controlling factor major control of hydrogen isotope fractionation. for cyanobacterial blooms. In order to clarify this issue, we isolated A series of controlled mesocosm experiments the potential effects of growth rate on fatty manipulated redox conditions by changing acid fractionation by employing continuous headspace gas supply and light availability. In culturing techniques for multiple species of sediments, mineralogy and P speciation were bacteria where the only variable altered was examined using in-situ voltammetry, XRF, growth rate. Our results indicate that there is a SEDEX extractions, and enzyme hydrolysis large and significant fractionation of hydrogen of different organic P pools. In water samples, in fatty acid production directly correlated to soluble reactive P, total P, enzyme digested P, growth rate. and metals content at different filter fractions were obtained. Significant flux of P across the SWI to the water column required an initial 1-2-week interval of increasingly reducing conditions. Fluctuating redox conditions likely favor a weakly bound sediment P pool sorbed to precursor iron oxyhydroxides, priming the SWI for increased P mobility.

31 Preliminary biogeochemical Illuminating environmental and characterization of sediments from molecular controls on aerobic Lake Sibinacocha, Peruvian Andes anoxygenic phototrophy

Benjamin Tiger1, Bronwen Konecky1, Neil Michelutti2, Christopher Gabriel Vargas, Maureen Coleman Grooms2, Jack Hutchings1, Preston Sowell3, John P. Smol2 Department of the Geophysical Sciences, University of Chicago 1 Department of Earth and Planetary Sciences, Washington University, USA, 2 Paleoecological Environmental Assessment and Research Laboratory, Queen’s University, Canada, 3 Sibinacocha Watershed Aerobic anoxygenic phototrophy (AAP) Project, USA is a metabolic process found in diverse proteobacteria and widespread across aquatic High-elevation regions are particularly environments. Unlike classical anoxygenic vulnerable to the physical and ecological photosynthetic bacteria, the bacteria that consequences of global climate change. perform AAP are often obligate aerobes and The high Andes are at the forefront of these are thought to use this pathway to supplement changes due to their sensitivity to fluctuations their primarily heterotrophic metabolism. in glacial mass and energy balance. In this The environmental and molecular factors that study, we present a preliminary biogeochemical characterization of sediment cores from Lake control AAP, however, are poorly understood. Sibinacocha, Peru, which sits at ~5,000m asl in Using the model organism Erythrobacter a rapidly deglaciating catchment adjacent to the longus, we constructed deletion mutants for Quelccaya Ice Cap. Due to its remote location several genes potentially involved with AAP. and large size, Sibinacocha’s sediments have not Light enhanced the growth of wild-type E. been well studied to gain a paleoclimatological longus on acetate or pyruvate minimal medium, or paleoenvironmental understanding of the but not in rich medium. Furthermore, the region. Gravity cores spanning ~25 cm and light contribution to the growth of E. longus roughly 300 years of sedimentation were taken was more important under carbon limited in 2017 and 2018 from the northern section conditions. We hypothesized that this advantage of the lake close to its glacial source. Initial could involve the glyoxylate shunt, a pathway

investigations found that fossil diatoms changed which allows cells to conserve two CO2 per from predominately planktonic to benthic each acetyl-CoA molecule that enter the TCA assemblages within the past several centuries. cycle. If this hypothesis were true, we predicted We analyzed the sediment cores for bulk carbon that mutants deficient in the glyoxylate shunt and nitrogen content as well as isotope ratios would no longer have a growth advantage in using EA-IRMS to characterize geochemical the light. Contrary to this prediction, a mutant changes. We found that bulk carbon, nitrogen, lacking isocitrate lyase (Dicl), the first gene in 13 and δ C are fairly constant until the mid-1800’s. the glyoxylate pathway, maintained a growth 13 Around 1850, δ C became more negative, advantage in the light, suggesting that the and the concentrations of carbon and nitrogen glyoxylate shunt is not solely responsible for increase, indicating substantial changes in the benefit of AAP. In contrast, a strain lacking productivity. Additionally, concentrations of bchID, two genes involved in the biosynthesis sedimentary chlorophyll a (including its main of bacteriochlorophyll-a, had similar growth in diagenetic products) were found to be constant light and dark on pyruvate minimal medium, until the mid-1800’s when they started to rapidly implying that Bchl-a is essential for the light- increase, also possibly indicating an increase in productivity. Our results show marked changes driven growth phenotype. An important next step in several proxies from the Laguna Sibincocha is to identify molecular regulators of the AAP cores over the past ~300 years, indicating the process in E. longus. Elucidating the molecular potential for detailed paleoenvironmental mechanisms underlying AAP is essential for reconstructions from this climatically-sensitive understanding the distribution and activity of region. this metabolism in aquatic ecosystems. 32 Formation and Stabilization of Mixed sources of n-alkanes in the Biogenic Vaterite late Ediacaran in the East European platform constrained by rimary R. Seth Wood1, Bryan Chakoumakos2, Brenda Pracheil1 P 1Environmental Sciences Division, Oak Ridge National Laboratory Compound-specific hydrogen isotopic 2 (ORNL), Neutron Scattering Division, ORNL composition

Vaterite is a metastable calcium carbonate Ming Wu1, David Fike2, Alexander Bradley3 1Washington University in St. Louis, St. Louis, USA, mingwu@wustl. polymorph that appears to be a common, if not edu (*presenting author), 2Washington University in St. Louis, St. obligatory, transient phase between amorphous Louis, USA, [email protected],3 Washington University in St. calcium carbonate (ACC) and calcite in Louis, St. Louis, USA, [email protected] supersaturated environments. Yet, due to its Several mechanisms have been suggested to instability, vaterite is rarely found in modern explane the inverse isotopic ordering in the environments - let alone the geological record. δ13C of n-alkanes, isoprenoids, and kerogen Instead, vaterite is almost exclusively observed in Proterozoic hydrocarbons including in biogenic structures of certain foraminifera, intensive heterotrophic reworking, preferential sea squirts, gastropods, and fish. Comparatively, preservation of heterotrophic organic carbon biogenic vaterite is more stable than its abiotic and/or a ‘mat-seal’ effect, and major contribution counterpart, which may be attributable to from prokaryotic phytoplankton. Characteristic organic macromolecules that inhibit Ostwald hydrogen isotopic fractionations associated ripening. One of the most notable and semi- heterotrophic and autotrophic metabolisms common forms of biogenic vaterite is found in provide a potential tool to constrain sources otoliths, the accretionary earbones of fish. In of hydrocarbons. Previous studies have shown some fish, such as lake sturgeon and Chinook that the hydrocarbons in the late Ediacaran salmon, vaterite can precipitate concurrently formation in the East European Platform are in with aragonite and calcite, yet remain stable in low maturity without/with little contamination. solution for fifty-plus years. Here, we discuss the So the primary hydrogen isotopic composition use of wide-angle neutron diffraction (WAND), of hydrocarbons is probably retained as it x-ray fluorescence (XRF), single-crystal is vulberable to secondary alteration at high X-ray diffraction (SC-XRD), micro-Raman, temperature. However, the conspicuous UCM and controlled precipitation experiments to makes direct measurement of compound-specific elucidate the mineralogical composition of hydrogen isotopes of hydrocarbons impossible. bulk otoliths, the spatial distribution of calcium Through molecular seiving and purification of carbonate polymorphs and trace elements, and hydrocarbons using HPLC, compound-specific the potential biotic and abiotic factors effecting hydrocarbon isotopic composition of pure the stabilization of vaterite. n-alkanes are constrained. The δD values of n-alkanes of all the measured samples show a “U” shape, ranging approximately from -250‰ to -50‰. The short-chain and long-chain n-alkanes are more enriched in δD compared to mid-chain n-alkanes with a difference as large as 150‰ in individual samples. So the n-alkanes in the Ediacaran samples are mixed sourced which will be discussed during the conference.

33 Salinity information from lipid The Influence of Earth biomarker isotope ratios in a central Abundant Minerals in Deep tropical Pacific lake sediment Ocean Hydrothermal Organic record Transformations

D. A. Wyman1, J.L Conroy1,2, M. Osburn3 Ziming Yang1, Xuan Fu1, Yiju Liao1, Isaac Thelander1 1 Deparment of Geology University of IllinoisUrbana-Champaign, 1Department of Chemistry, Oakland University, Rochester, MI, USA 2Department of Plant Biology, University of IllinoisUrbana- Champaign, 3 Department of Earth and Planetary Sciences, Northwestern University, Chicago Geochemical processes in deep-ocean hydrothermal systems influence the transport and Variability in tropical Pacific Walker Circulation degradation of sedimentary organic matter, the and the nature of the Intertropical Convergence metabolisms of seafloor biosphere, and the deep Zone (ITCZ) on centennial timescales over carbon and nitrogen cycles. Minerals can play a the last millennium remains uncertain given significant role in hydrothermal transformation the diverse conclusions of palepohydrologic of deep marine organic compounds, but much proxies across the tropical Pacific. Here we still remains unknown about how minerals use biomarker stable isotope ratios from a lake control the reaction pathways of organic sediment record taken from a brackish (28 ppt) carbon and organic nitrogen. In this study, we lake on Kiritimati, in the central tropical Pacific, developed a laboratory-simulated hydrothermal to reconstruct lake salinity and paleohydrology system and investigated the effects of several over the last millennium. Total lipid extracts Earth-abundant minerals on ketone and (TLE) and specific biomarkers were extracted amine reactions, respectively, under specific and the dD values were measured at decadal hydrothermal conditions. We found that several resolution over the last millennium. Preliminary iron-containing minerals could significantly results show lower dDTLE values corresponding increase ketone hydrothermal reactivity through with thicker, darker microbial mats and more promoted fragmentation or reduction pathway, positive dDTLE corresponding with gypsum rich whereas decomposition of amines were less units. A published transfer function relating influenced by the presence of the selected salinity to dDTLE indicates this latter period of minerals. Based on product distribution analysis, high dDTLE corresponds to lake water of 4.33- we also provided detailed reaction pathways and 135 ppt. However, this transfer function also plausible mechanisms for the studied organic- suggets modern salinity of 71.2 ppt, 43 ppt mineral hydrothermal interactions. Our results higher than measured. Thus, variations in dDTLE suggest a highly selective role of minerals in likely reflect different microbial communities organic carbon and nitrogen transformations in downcore, rather than the dD of lake water and deep-ocean hydrothermal environments. its relationship with salinity. We plan future research on compound specific dD, paried with inorganic carbonate d18O and detailed isotope- based hydrologic balance modeling, to further define the relationship between biomarker dD and salinity.

34 Adsorption of selenite onto bacillus subtilis: the overlooked role of cell envelope sulfhydryl sites in the microbial conversion of Se(IV)

Qiang Yu1,*, Maxim I. Boyanov2,3, Jinling Liu14, Kenneth M. Kemner3, Jeremy B. Fein1 1Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA (* presenting author), 2Bulgarian Academy of Sciences, Institute of Chemical Engineering, Sofia, 1113, Bulgaria,3 Biosciences Division, Argonne National Laboratory, Argonne, IL 60439, USA, 4School of Earth Science, China University of Geoscience, Wuhan 430074, China

Microorganisms can reduce, methylate and assimilate Se, controlling the fate and transport of Se in the environment. However, the mechanisms controlling these microbial activities are still poorly understood. In particular, it is unknown how the negatively-charged Se(IV) and Se(VI) oxyanions that dominate the aqueous Se speciation in oxidizing environments bind to negatively-charged microbial cell surfaces in order to become bioavailable.

In this study, the role of sulfhydryl sites in the adsorption was determined by comparing selenite adsorption onto the Bacillus subtilis biomass with and without sulfhydryl sites blocked chemically, and the Se speciation on the biomass was analyzed using XANES and EXAFS spectroscopy. Our results show that the adsorption of selenite onto Bacillus subtilis bacterial cells is controlled by cell envelope sulfhydryl sites. Once adsorbed onto the bacteria, selenite is reduced, and forms reduced organo-Se compounds (e.g., R1S-Se-SR2). Because sulfhydryl sites are present within cell envelopes of a wide range of bacterial species, sulfhydryl-controlled adsorption of selenite likely represents a general mechanism adopted by bacteria to make selenite bioavailable. Therefore, sulfhydryl binding of selenite likely occurs in a wide range of oxidized Se-bearing environments, and because it is followed by microbial conversion of selenite to other Se species, the process represents a crucial step in the global cycling of Se.