Scholarship & Research
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/1
Browse
4 results
Search Results
Item Covariation of hot spring geochemistry with microbial genomic diversity, function, and evolution(Springer Science and Business Media LLC, 2024-08) Colman, Daniel R.; Keller, Lisa M.; Arteaga-Pozo, Emilia; Andrade-Barahona, Eva; St. Clair, Brian; Shoemaker, Anna; Cox, Alysia; Boyd, Eric S.The geosphere and the microbial biosphere have co-evolved for ~3.8 Ga, with many lines of evidence suggesting a hydrothermal habitat for life’s origin. However, the extent that contemporary thermophiles and their hydrothermal habitats reflect those that likely existed on early Earth remains unknown. To address this knowledge gap, 64 geochemical analytes were measured and 1022 metagenome-assembled-genomes (MAGs) were generated from 34 chemosynthetic high-temperature springs in Yellowstone National Park and analysed alongside 444 MAGs from 35 published metagenomes. We used these data to evaluate co-variation in MAG taxonomy, metabolism, and phylogeny as a function of hot spring geochemistry. We found that cohorts of MAGs and their functions are discretely distributed across pH gradients that reflect different geochemical provinces. Acidic or circumneutral/alkaline springs harbor MAGs that branched later and are enriched in sulfur- and arsenic-based O2-dependent metabolic pathways that are inconsistent with early Earth conditions. In contrast, moderately acidic springs sourced by volcanic gas harbor earlier-branching MAGs that are enriched in anaerobic, gas-dependent metabolisms (e.g. H2, CO2, CH4 metabolism) that have been hypothesized to support early microbial life. Our results provide insight into the influence of redox state in the eco-evolutionary feedbacks between thermophiles and their habitats and suggest moderately acidic springs as early Earth analogs.Item Morphology, timing, and drivers of post-glacial landslides in the northern Yellowstone region(Wiley, 2024) Dixon, Jean L.; Nicholas, Grace E.; Pierce, Kenneth L.; Lageson, DavidThe withdrawal of glaciers in mountainous systems exposes over-steepened slopes previously sculpted by ice. This debuttressing can directly trigger mass movements or leave slopes susceptible to them by other drivers, including seismogenic shaking and changing climate conditions. These systems may pose hazards long after deglaciation. Here, we investigate the drivers of slope failure for landslides at the northern entrance to Yellowstone National Park, a critical conduit traversed by ~1 million visitors each year. Through field mapping and analyses of LiDAR data, we quantify the spatial and temporal relationships between eight adjacent slides. Stratigraphic relationships and surface roughness analyses suggest initial emplacement 13–11.5 ka, after a significant delay from Deckard Flats glacial retreat (15.1 ± 1.2 ka). Thus, rapid glacial debuttressing was not the direct trigger of slope failure, though the resultant change in stress regime likely had a preparatory influence. We posit that the timing of failure was associated with (1) a period of enhanced moisture and seismicity in the late Pleistocene and (2) altered stress regimes associated with ice retreat. Historical archives and cross-cutting relationships indicate portions of some ancient slides were reactivated; these areas are morphologically distinguishable from other slide surfaces, with mean topographic roughness 2 times that of non-active slides. Stream power analysis and archival records indicate Holocene incision of the Gardner River and human disturbances are largely responsible for modern reactivations. Our findings highlight the importance of combining archival records with stratigraphic, field and remote sensing approaches to understanding landslide timing, risk, and drivers in post-glacial environments. This study also provides a valuable baseline for geomorphic change in the Yellowstone system, where a 2022 flood incised streams, damaged infrastructure and further reactivated landslide slopes.Item Travertine records climate-induced transformations of the Yellowstone hydrothermal system from the late Pleistocene to the present(Geological Society of America, 2024-02) Harrison, Lauren N.; Hurwitz, Shaul; Paces, James B.; Whitlock, Cathy; Peek, Sara; Licciardi, JosephChemical changes in hot springs, as recorded by thermal waters and their deposits, provide a window into the evolution of the postglacial hydrothermal system of the Yellowstone Plateau Volcanic Field. Today, most hydrothermal travertine forms to the north and south of the ca. 631 ka Yellowstone caldera where groundwater flow through subsurface sedimentary rocks leads to calcite saturation at hot springs. In contrast, low-Ca rhyolites dominate the subsurface within the Yellowstone caldera, resulting in thermal waters that rarely deposit travertine. We investigated the timing and origin of five small travertine deposits in the Upper and Lower Geyser Basins to understand the conditions that allowed for travertine deposition. New 230Th-U dating, oxygen (δ18O), carbon (δ13C), and strontium (87Sr/86Sr) isotopic ratios, and elemental concentrations indicate that travertine deposits within the Yellowstone caldera formed during three main episodes that correspond broadly with known periods of wet climate: 13.9−13.6 ka, 12.2−9.5 ka, and 5.2−2.9 ka. Travertine deposition occurred in response to the influx of large volumes of cold meteoric water, which increased the rate of chemical weathering of surficial sediments and recharge into the hydrothermal system. The small volume of intracaldera travertine does not support a massive postglacial surge of CO2 within the Yellowstone caldera, nor was magmatic CO2 the catalyst for postglacial travertine deposition.Item Formaldehyde as a carbon and electron shuttle between autotroph and heterotroph populations in acidic hydrothermal vents of Norris Geyser Basin, Yellowstone National Park(2016-05) Moran, James J.; Whitmore, Laura M.; Isern, Nancy G.; Romine, Margaret F.; Riha, Krystin M.; Inskeep, William P.; Kreuzer, Helen W.The Norris Geyser Basin in Yellowstone National Park contains a large number of hydrothermal systems, which host microbial populations supported by primary productivity associated with a suite of chemolithotrophic metabolisms. We demonstrate that Metallosphaera yellowstonensis MK1, a facultative autotrophic archaeon isolated from a hyperthermal acidic hydrous ferric oxide (HFO) spring in Norris Geyser Basin, excretes formaldehyde during autotrophic growth. To determine the fate of formaldehyde in this low organic carbon environment, we incubated native microbial mat (containing M. yellowstonensis) from a HFO spring with 13C-formaldehyde. Isotopic analysis of incubation-derived CO2 and biomass showed that formaldehyde was both oxidized and assimilated by members of the community. Autotrophy, formaldehyde oxidation, and formaldehyde assimilation displayed different sensitivities to chemical inhibitors, suggesting that distinct sub-populations in the mat selectively perform these functions. Our results demonstrate that electrons originally resulting from iron oxidation can energetically fuel autotrophic carbon fixation and associated formaldehyde excretion, and that formaldehyde is both oxidized and assimilated by different organisms within the native microbial community. Thus, formaldehyde can effectively act as a carbon and electron shuttle connecting the autotrophic, iron oxidizing members with associated heterotrophic members in the HFO community.