Leveraging the carbonate record from regional hydroclimate to microbial ecology

Org. and inorg. stable isotopes of lacustrine carbonate sediments are commonly used in reconstructions of ancient terrestrial environments. However, different carbonate fabrics can form contemporaneously by localized processes within a single lake. Microbes and hydrol. alter the chem. of their local environments, which can overprint the broader environmental signal preserved in the carbonate record. In this work, we explore the susceptibility of different lacustrine carbonate facies to early diagenetic and in situmicrobial processes. To do so, we characterize geochem. and stable isotopic variability of carbonate minerals, org. matter, and water within one modern lake (Great Salt Lake, UT) within the context of seasonal and site-specific 16S rRNA amplicon sequencing community profiles. We find that facies equiv. to ooid grainstones provide time-averaged records of lake chem. that are resistant to alteration by microbial activity, whereas microbialite, intraclasts, and carbonate mud are more susceptible to local microbial influence and hydrol. Further, we find localized occurrences of clumpedisotopic disequil. in the near subsurface likely driven by local microbial metab. (e.g. sulfur cyclers) during authigenic carbonate pptn. Our findings provide a framework for leveraging carbonate facies-specific C, O, and clumped isotope records in ancient lakes to reconstruct both regional hydroclimate and local microbial ecol

Carbonate facies-specific stable isotope data record climate, hydrology, and microbial communities in Great Salt Lake, UT

Organic and inorganic stable isotopes of lacustrine carbonate sediments are commonly used in reconstructions of ancient terrestrial ecosystems and environments. Microbial activity and local hydrological inputs can alter porewater chemistry (e.g., pH, alkalinity) and isotopic composition (e.g., δ¹⁸O_(water), δ¹³C_(DIC)), which in turn has the potential to impact the stable isotopic compositions recorded and preserved in lithified carbonate. The fingerprint these syngenetic processes have on lacustrine carbonate facies is yet unknown, however, and thus, reconstructions based on stable isotopes may misinterpret diagenetic records as broader climate signals. Here, we characterize geochemical and stable isotopic variability of carbonate minerals, organic matter, and water within one modern lake that has known microbial influences (e.g., microbial mats and microbialite carbonate) and combine these data with the context provided by 16S rRNA amplicon sequencing community profiles. Specifically, we measure oxygen, carbon, and clumped isotopic compositions of carbonate sediments (δ¹⁸Ocarb, δ¹³C_(carb), ∆₄₇), as well as carbon isotopic compositions of bulk organic matter (δ¹³C_(org)) and dissolved inorganic carbon (DIC; δ¹³C_(DIC)) of lake and porewater in Great Salt Lake, Utah from five sites and three seasons. We find that facies equivalent to ooid grainstones provide time‐averaged records of lake chemistry that reflect minimal alteration by microbial activity, whereas microbialite, intraclasts, and carbonate mud show greater alteration by local microbial influence and hydrology. Further, we find at least one occurrence of ∆₄₇ isotopic disequilibrium likely driven by local microbial metabolism during authigenic carbonate precipitation. The remainder of the carbonate materials (primarily ooids, grain coatings, mud, and intraclasts) yield clumped isotope temperatures (T(∆₄₇)), δ¹⁸O_(carb), and calculated δ¹⁸O_(water) in isotopic equilibrium with ambient water and temperature at the time and site of carbonate precipitation. Our findings suggest that it is possible and necessary to leverage diverse carbonate facies across one sedimentary horizon to reconstruct regional hydroclimate and evaporation–precipitation balance, as well as identify microbially mediated carbonate formation

Stromatolites in Walker Lake (Nevada, Great Basin, USA) record climate and lake level changes ~ 35,000 years ago

Walker Lake is a closed-basin remnant of the large Pleistocene glacial Lake Lahontan system that has experienced multiple high amplitude (100–200 m) changes in water level over the past ~ 40,000 years in response to changes in climate. A laminated carbonate stromatolite composed of varying proportions of calcite fans and micrite was collected from a paleoshoreline located at approximately 58 m above present lake level. Radiocarbon dating revealed that the stromatolite spans approximately 2000 years of growth, from 35,227 to 33,727 calibrated years before present (YBP), a time period during which paleolake-level is not well-constrained. Distinct laminae were drilled along the growth axis, and the resulting powders were collected for clumped isotope analyses to generate formation temperatures (lake water temperatures) during stromatolite formation from which δ18Owater was calculated. Results indicate that the stromatolite experienced an initial increase in temperature and water δ18O values followed by a decrease in both during the course of accretion. The resulting temperature and isotopic data were input into a Rayleigh distillation model for lakewater evaporation in order to estimate the magnitude of lake level and volume fluctuations over the course of accretion. Modeling results reveal a lake level decrease of between 8.1 and 15.6 m, followed by an increase of between 4.3 and 8.8 m during the course of stromatolite growth. The results of this study indicate that Walker Lake experienced significant lake volume change over the course of 2000 years, perhaps as a response to precipitation changes driven by fluctuations in the polar jet stream and accompanying changes in regional climate, and/or evaporation-induced changes in lake level. These results add to a growing body of research indicating that stromatolites and other lacustrine tufas represent a detailed and extensive terrestrial archive that can potentially be used to reconstruct the timing and magnitude of climate change

The Astrobiology Primer v2.0

Astrobiology is the science that seeks to understand the story of life in our universe. Astrobiology includes investigation of the conditions that are necessary forlife to emerge and flourish, the origin of life, the ways that life has evolved and adaptedto the wide range of environmental conditions here on Earth, the search for life beyondEarth, the habitability of extraterrestrial environments, and consideration of the future oflife both here on Earth and elsewhere. It therefore requires knowledge of physics,chemistry and biology, and many more specialized scientific areas including astronomy,geology, planetary science, microbiology, atmospheric science and oceanography.Fil: Domagal Goldman, Shawn D.. National Aeronautics And Space Administration; Estados UnidosFil: Wright, Katherine. University Of Bristol; Reino UnidoFil: Adamala, Katarzyna. University Of Minnesota; Estados UnidosFil: Antonio, Marina. Washington State University. School Of Earth & Environmental Sciences; Estados UnidosFil: Arino de la Rubia, Leigh. University Of New South Wales; AustraliaFil: Carter Bond, Jade. University Of New South Wales; AustraliaFil: Dartnell, Lewis. University Of Leicester; Reino UnidoFil: Goldman, Aaron. Oberlin College; Reino UnidoFil: Paulino Lima, Ivan Glaucio. National Aeronautics And Space Administration; Estados UnidosFil: Lynch, Kennda. Colorado School; Estados UnidosFil: Naud, Marie Eve. Université Du Québec A Montreal; CanadáFil: Singer, Kelsi. Southwest Research Institute; Estados UnidosFil: Abrevaya, Ximena Celeste. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Anderson, Rika. University of Washington; Estados UnidosFil: Arney, Giada. University of Washington; Estados UnidosFil: Atri, Dimitra. International Centre Of Theoretical Science. Tata Institute Of Fundamental Research; EspañaFil: Azua Bustos, Armando. Pontificia Universidad Católica de Chile; ChileFil: Bowman, Jeff. Lamont Doherty Earth Observatory; Estados UnidosFil: Brazelton, William. University of Utah; Estados UnidosFil: Brennecka, Gregory. Westfalische Wilhelms Universitat; AlemaniaFil: Carns, Regina. University of Washington; Estados UnidosFil: Chopra, Adytia. Australian National University; AustraliaFil: Collangelo Lillis, Jess. McGill University; Estados UnidosFil: Crockett, Christopher. University Of Carnegie Mellon; Estados UnidosFil: DeMarines, Julia. University Of Carnegie Mellon; Estados UnidosFil: Frank, Elizabeth. University Of Carnegie Mellon; Estados UnidosFil: Frantz, Carie. University of Washington; Estados UnidosFil: Galante, Douglas. Brazilian Synchrotron Light Laboratory; BrasilFil: Glass, Jennifer. Georgia Institute Of Techology; Estados UnidosFil: Gleeson, Damhait. Instituto Nacional de Tecnica Aeroespacial; Españ

The Astrobiology Primer v2.0

Astrobiology is the science that seeks to understand the story of life in our universe. Astrobiology includes investigation of the conditions that are necessary for life to emerge and flourish, the origin of life, the ways that life has evolved and adapted to the wide range of environmental conditions here on Earth, the search for life beyond Earth, the habitability of extraterrestrial environments, and consideration of the future of life here on Earth and elsewhere. It therefore requires knowledge of physics, chemistry, biology, and many more specialized scientific areas including astronomy, geology, planetary science, microbiology, atmospheric science, and oceanography. However, astrobiology is more than just a collection of different disciplines. In seeking to understand the full story of life in the Universe in a holistic way, astrobiology asks questions that transcend all these individual scientific subjects. Astrobiological research potentially has much broader consequences than simply scientific discovery, as it includes questions that have been of great interest to human beings for millennia (e.g., are we alone?) and raises issues that could affect the way the human race views and conducts itself as a species (e.g., what are our ethical responsibilities to any life discovered beyond Earth?)