Horizontal gene transfer is an important driver of adaptation and evolution in microorganisms. Transducing biological nanoparticles such as viral particles are believed to be key facilitators of horizontal gene transfer. In deep subseafloor sediments, energy can be highly limiting, supporting only extremely slow metabolisms. In such low-energy, isolated environments where communities may subsist for millions of years, the mechanisms of subsurface microbial adaptation and evolution remain a mystery. Virus particles have been found everywhere that life has been found, including deep subsurface environments. Although microorganisms are abundant and active in the Earth's subsurface, the role of viruses in shaping and influencing these slow-growing communities is only recently starting to be explored. Here, we analyzed the deeply buried microbial community from a lignite coalbed layer 2km below the seafloor offshore Shimokita, Japan (IODP Expedition 337) that had been buried for 20 million years. We harvested cells (>0.2µm) and biological nanoparticles (<0.2µm) from a bioreactor enrichment seeded by lignite core samples. We sequenced DNA from the cells and nanoparticles and subsequently analyzed the metagenomes. Within the nanoparticle metagenome, numerous complete novel virus genomes were reconstructed. Comparison of the virus genomes to the prokaryotic MAGs (metagenome assembled genomes) revealed that many of the virus genomes had been integrated prophage within bacterial genomes, suggesting the potential for virus-host interactions to occur in the deep subseafloor. Additionally, lysogeny may be an important survival mechanism for viruses in deeply buried, low-energy environments. Host genes were found to be packaged by viral particles, demonstrating the potential for specialized and general transduction by viruses. Not only viral particles, but there was also evidence that membrane vesicles and gene transfer agents may participate in transduction in this deep subsurface community. Horizontal gene transfer mediated by biological nanoparticles may be an important mechanism of adaptation for deep subsurface microbial communities and may provide insight into possible evolutionary processes shaping microbial communities in the deep subsurface. These results may also shed some light onto the nature of viral infection in the subsurface, potentially revealing insights about the long-term persistence of life under extreme energy limitation and how viruses may survive this over geological timescales.
{"title":"Viruses, Vesicles, and other Biological Nanoparticles: The Sub-cellular Biosphere of a Deeply Buried 2km-Deep, 20-Million-Year-Old Coalbed Community","authors":"Donald Pan, Shun’ichi Ishii, Miho Hirai, Miyuki Ogawara, Wenjing Zhang, Eiji Tasumi, Fumio Inagaki, Hiroyuki Imachi","doi":"10.3897/aca.6.e109928","DOIUrl":"https://doi.org/10.3897/aca.6.e109928","url":null,"abstract":"Horizontal gene transfer is an important driver of adaptation and evolution in microorganisms. Transducing biological nanoparticles such as viral particles are believed to be key facilitators of horizontal gene transfer. In deep subseafloor sediments, energy can be highly limiting, supporting only extremely slow metabolisms. In such low-energy, isolated environments where communities may subsist for millions of years, the mechanisms of subsurface microbial adaptation and evolution remain a mystery. Virus particles have been found everywhere that life has been found, including deep subsurface environments. Although microorganisms are abundant and active in the Earth's subsurface, the role of viruses in shaping and influencing these slow-growing communities is only recently starting to be explored. Here, we analyzed the deeply buried microbial community from a lignite coalbed layer 2km below the seafloor offshore Shimokita, Japan (IODP Expedition 337) that had been buried for 20 million years. We harvested cells (&gt;0.2µm) and biological nanoparticles (&lt;0.2µm) from a bioreactor enrichment seeded by lignite core samples. We sequenced DNA from the cells and nanoparticles and subsequently analyzed the metagenomes. Within the nanoparticle metagenome, numerous complete novel virus genomes were reconstructed. Comparison of the virus genomes to the prokaryotic MAGs (metagenome assembled genomes) revealed that many of the virus genomes had been integrated prophage within bacterial genomes, suggesting the potential for virus-host interactions to occur in the deep subseafloor. Additionally, lysogeny may be an important survival mechanism for viruses in deeply buried, low-energy environments. Host genes were found to be packaged by viral particles, demonstrating the potential for specialized and general transduction by viruses. Not only viral particles, but there was also evidence that membrane vesicles and gene transfer agents may participate in transduction in this deep subsurface community. Horizontal gene transfer mediated by biological nanoparticles may be an important mechanism of adaptation for deep subsurface microbial communities and may provide insight into possible evolutionary processes shaping microbial communities in the deep subsurface. These results may also shed some light onto the nature of viral infection in the subsurface, potentially revealing insights about the long-term persistence of life under extreme energy limitation and how viruses may survive this over geological timescales.","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136032506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adam Ruka, Johannes Scheichhart, Jiří Doležal, Kateřina Čapková, Travis Meador, Roey Angel, Rosa Paulina Calvillo-Medina, Zuzana Chlumská, Nadine Praeg, Paul Illmer, Klára Řeháková
Alpine biomes experience harsh environmental conditions and short growing seasons, which necessitate interspecific and intraspecific interactions to ensure the stability of diversity and ecosystem multifunctionality. The relationship between plants and microbes in this environment is equally dynamic, with seasonal pulses of nutrients and the phenology of plants creating specific "hot moments" of biogeochemical activity. As a crucial zone of interaction between plant roots and microbial communities, the rhizosphere serves as a "hot spot" of biogeochemical cycling where the mineralization of nutrients, such as carbon, nitrogen, and phosphorus, allows for the transfer of nutrients between trophic levels. However, the nature of these interactions depends on edaphic and climatic conditions, potentially leading to cooperation or competition to meet the stoichiometric demands of organisms. Elevation gradients within alpine ecosystems provide dramatic shifts in temperature, precipitation, and soil development that allow for the study of these interactions over short geographical distances. In conjunction with seasonal sampling, this approach can provide a wide environmental context to observe the relationship between specific plants and microbial communities. By investigating the C/N ratios of plants, microbes, and soil, as well as microbial enzymatic potential, we can infer nutrient limitations, temporal niche partitioning, and biological responses to abiotic conditions. Within the Austrian Alps, we studied a selection of herbaceous plants and their associated microbial communities across an elevation gradient spanning 2200-2800 m (Fig. 1). The primary aims of the study were to assess the seasonal changes in C/N stoichiometry from both trophic levels, microbial enzymatic potential, and rhizosphere diversity of bacterial and fungal communities. To fulfill these aims, four locations were selected based on the two present biomes (alpine meadow and sub-nival zone) and the transition between them. Four to five plant species were collected during each season in 2023, including the often-neglected snow-covered winter season, along with rhizosphere and bulk soil for microbial biomass measurements and soil chemistry. Plant leaf tissue samples were analyzed using Isotope-ratio mass spectrometry for plant C/N ratios, while soil and microbial C/N ratios were calculated using chloroform fumigation extraction. Microbial enzymatic potential was assessed using hydrolase enzymatic assays for five fluorophore-labeled substrates. 16S-rRNA and 18S-rRNA genes were sequenced using an Illumina MiSeq platform from the fine roots of collected plant individuals to quantify the relative abundances of bacterial and fungal taxa. The findings of our study indicate that the higher microbial biomass (Cmic) in alpine meadow locations leads to increased enzymatic activity compared to sub-nival zones. However, specific plant species were found to enhance microbial biomass and enzymatic p
{"title":"Seasonal Relationships of Alpine Plants and Microbes through a Stoichiometric and Enzymatic Lens","authors":"Adam Ruka, Johannes Scheichhart, Jiří Doležal, Kateřina Čapková, Travis Meador, Roey Angel, Rosa Paulina Calvillo-Medina, Zuzana Chlumská, Nadine Praeg, Paul Illmer, Klára Řeháková","doi":"10.3897/aca.6.e108599","DOIUrl":"https://doi.org/10.3897/aca.6.e108599","url":null,"abstract":"Alpine biomes experience harsh environmental conditions and short growing seasons, which necessitate interspecific and intraspecific interactions to ensure the stability of diversity and ecosystem multifunctionality. The relationship between plants and microbes in this environment is equally dynamic, with seasonal pulses of nutrients and the phenology of plants creating specific \"hot moments\" of biogeochemical activity. As a crucial zone of interaction between plant roots and microbial communities, the rhizosphere serves as a \"hot spot\" of biogeochemical cycling where the mineralization of nutrients, such as carbon, nitrogen, and phosphorus, allows for the transfer of nutrients between trophic levels. However, the nature of these interactions depends on edaphic and climatic conditions, potentially leading to cooperation or competition to meet the stoichiometric demands of organisms. Elevation gradients within alpine ecosystems provide dramatic shifts in temperature, precipitation, and soil development that allow for the study of these interactions over short geographical distances. In conjunction with seasonal sampling, this approach can provide a wide environmental context to observe the relationship between specific plants and microbial communities. By investigating the C/N ratios of plants, microbes, and soil, as well as microbial enzymatic potential, we can infer nutrient limitations, temporal niche partitioning, and biological responses to abiotic conditions. Within the Austrian Alps, we studied a selection of herbaceous plants and their associated microbial communities across an elevation gradient spanning 2200-2800 m (Fig. 1). The primary aims of the study were to assess the seasonal changes in C/N stoichiometry from both trophic levels, microbial enzymatic potential, and rhizosphere diversity of bacterial and fungal communities. To fulfill these aims, four locations were selected based on the two present biomes (alpine meadow and sub-nival zone) and the transition between them. Four to five plant species were collected during each season in 2023, including the often-neglected snow-covered winter season, along with rhizosphere and bulk soil for microbial biomass measurements and soil chemistry. Plant leaf tissue samples were analyzed using Isotope-ratio mass spectrometry for plant C/N ratios, while soil and microbial C/N ratios were calculated using chloroform fumigation extraction. Microbial enzymatic potential was assessed using hydrolase enzymatic assays for five fluorophore-labeled substrates. 16S-rRNA and 18S-rRNA genes were sequenced using an Illumina MiSeq platform from the fine roots of collected plant individuals to quantify the relative abundances of bacterial and fungal taxa. The findings of our study indicate that the higher microbial biomass (Cmic) in alpine meadow locations leads to increased enzymatic activity compared to sub-nival zones. However, specific plant species were found to enhance microbial biomass and enzymatic p","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136032837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the Earth’s deep subsurface life is comprised exclusively of microorganisms, and estimates indicate 12-45% of the global prokaryotic biomass, on the order of 10 29 microbes, is found in subseafloor sediments. Investigating how this enormous microbial biomass is maintained in the extreme habitats below seafloor is critical for understanding the rules of life in the deep biosphere. Furthermore, Earth’s subseafloor habitats often present analog environments detected in other planets such as the recently discovered “ocean worlds”, i.e., planetary bodies in our solar system which consist of large subsurface oceans including Saturn’s moons Titan and Enceladus and Jupiter’s moon Europa. Therefore, investigating life in and beneath Earth’s oceans remains at the forefront of the current astrobiological research endeavors. Despite the inhospitable nature of the subseafloor sedimentary realm, active microbial populations including bacteria capable of transforming into dormant endospores have been demonstrated to inhabit deeply buried anoxic sediments and oil reservoirs, permeable ocean crust, and around hydrothermal vents. These extreme habitats often remain physically connected to the seafloor by unique geological features such as marine cold seeps that transmit hydrocarbon-rich fluids originating in deep sediment layers. It remains unclear how fluid migration in cold seeps influence the composition of the seabed microbiome and if they transport deep subsurface life up to the surface. In this study, we addressed this knowledge gap by analyzing over 180 marine surficial sediments from the Gulf of Mexico and the Monterey Bay to assess whether hydrocarbon fluid migration serves as a mechanism for the dispersal of subsurface extremophiles and their introduction into the seabed via cold seeps. Seafloor samples were collected either by piston coring or ROV-operated push coring and were stored at -20°C upon collection. Presence of hydrocarbons in the piston core sediments wa characterized by gas chromatography mass spectrometry and fluorescence spectroscopy whereas gas seepage was determined in the ROV push cores by visual confirmation of gas bubbles emanating from the seafloor. Sediment microbiome composition was determined by high throughput 16S rRNA gene amplicon sequencing. Metabolic diversity was assessed via a genome-centric metagenomics approach aided by shotgun metagenomic sequencing of selected samples. Additionally, viable bacterial endospore communities were investigated from a subset of over 120 of the above samples by allowing endospore germination using a high-temperature incubation assay followed by amplicon sequencing. While 132 of the piston core sediments contained migrated liquid hydrocarbons, evidence of continuous advective transport of thermogenic alkane gases was observed in 11 sediments. Gas seeps harbored distinct microbial communities featuring bacteria and archaea that are well known inhabitants of deep biosphere sediments. Specifica
{"title":"Marine Cold Seeps As A Gateway Of Deep Subsurface Extremophiles To The Seafloor","authors":"Anirban Chakraborty, Bronwyn Ellis, Jayne Rattray, Casey Hubert","doi":"10.3897/aca.6.e108387","DOIUrl":"https://doi.org/10.3897/aca.6.e108387","url":null,"abstract":"In the Earth’s deep subsurface life is comprised exclusively of microorganisms, and estimates indicate 12-45% of the global prokaryotic biomass, on the order of 10 29 microbes, is found in subseafloor sediments. Investigating how this enormous microbial biomass is maintained in the extreme habitats below seafloor is critical for understanding the rules of life in the deep biosphere. Furthermore, Earth’s subseafloor habitats often present analog environments detected in other planets such as the recently discovered “ocean worlds”, i.e., planetary bodies in our solar system which consist of large subsurface oceans including Saturn’s moons Titan and Enceladus and Jupiter’s moon Europa. Therefore, investigating life in and beneath Earth’s oceans remains at the forefront of the current astrobiological research endeavors. Despite the inhospitable nature of the subseafloor sedimentary realm, active microbial populations including bacteria capable of transforming into dormant endospores have been demonstrated to inhabit deeply buried anoxic sediments and oil reservoirs, permeable ocean crust, and around hydrothermal vents. These extreme habitats often remain physically connected to the seafloor by unique geological features such as marine cold seeps that transmit hydrocarbon-rich fluids originating in deep sediment layers. It remains unclear how fluid migration in cold seeps influence the composition of the seabed microbiome and if they transport deep subsurface life up to the surface. In this study, we addressed this knowledge gap by analyzing over 180 marine surficial sediments from the Gulf of Mexico and the Monterey Bay to assess whether hydrocarbon fluid migration serves as a mechanism for the dispersal of subsurface extremophiles and their introduction into the seabed via cold seeps. Seafloor samples were collected either by piston coring or ROV-operated push coring and were stored at -20°C upon collection. Presence of hydrocarbons in the piston core sediments wa characterized by gas chromatography mass spectrometry and fluorescence spectroscopy whereas gas seepage was determined in the ROV push cores by visual confirmation of gas bubbles emanating from the seafloor. Sediment microbiome composition was determined by high throughput 16S rRNA gene amplicon sequencing. Metabolic diversity was assessed via a genome-centric metagenomics approach aided by shotgun metagenomic sequencing of selected samples. Additionally, viable bacterial endospore communities were investigated from a subset of over 120 of the above samples by allowing endospore germination using a high-temperature incubation assay followed by amplicon sequencing. While 132 of the piston core sediments contained migrated liquid hydrocarbons, evidence of continuous advective transport of thermogenic alkane gases was observed in 11 sediments. Gas seeps harbored distinct microbial communities featuring bacteria and archaea that are well known inhabitants of deep biosphere sediments. Specifica","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"31 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136033571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Astrobiologists seek to find life beyond Earth. The “Holy Grail” of Astrobiology research is to discover evidence of a second genesis of life – an origin of life that was independent from life’s origin on Earth. No formal consensus on the possibility for a second genesis of life exists, and opinions about the probability range from near zero to near unity. An extra-terrestrial example of life would help answer this question and settle the quandary of whether life is common in the Universe or exceedingly rare. Quantifying the “ordinariness” of life has far reaching philosophical implications that could even inform us about the future of intelligent, technology-wielding life on Earth (Bostrom 2007). Life on Mars, one of our closest planetary neighbors, was considered a forgone conclusion as recently as the mid 20 th century. What else besides an advanced civilization cultivating crops could have been responsible for the telescopically observed network of “canals” scarring its red surface? The “Advanced Martian Civilization” hypothesis had support from preeminent scientists, such as Giovanni Schiaparelli and Percival Lowell, but was relegated to the realm of pseudoscience when data from the Mariner spacecrafts in the 1970s failed to reveal any evidence for such civilizations. There is still no convincing evidence for life on Mars; however, several studies have at least raised one or two eyebrows (Mazur et al. 1978, McKay et al. 1996, Ruff and Farmer 2016). The Mariner missions ushered in the era of modern space exploration at Mars, and with it an earnest search for life. In 1976, shortly after the Mariner missions, the Viking I & II landers delivered “positive” results from their Labeled Release (LR) experiments. Oxidants in the martian regolith are the generally accepted explanation for these results, but some argue that life is the most parsimonious explanation for the Viking data (Levin and Straat 2016). We still do not know if life existed, or exists, on Mars, but Mars was once habitable for the forms of life that took root on early Earth and certain places on Mars likely remain habitable (Davila et al. 2010, Ehlmann et al. 2016). Its potential habitability and proximity to Earth have kept Mars centered in the crosshairs of Astrobiological research for decades. However, icy ocean worlds – Titan, Europa and Enceladus – have garnered increasing attention from the Astrobiology community (National Academies of Sciences and Medicine 2022), partially because any evidence for life on these worlds has a much higher chance of representing a second genesis whereas life on Mars could have potentially originated on Earth (or vice versa). The problems we face in the search for life on Mars today mirror those that confronted Schiaparelli and Lowell: we do not have data of sufficient quality to answer the question definitively. One major difference is that Schiaparelli and Lowell had their prior probability for the expectation of life on Mars set at what m
{"title":"Using AI to Fine Tune the Search for Life","authors":"Michael Phillips","doi":"10.3897/aca.6.e108253","DOIUrl":"https://doi.org/10.3897/aca.6.e108253","url":null,"abstract":"Astrobiologists seek to find life beyond Earth. The “Holy Grail” of Astrobiology research is to discover evidence of a second genesis of life – an origin of life that was independent from life’s origin on Earth. No formal consensus on the possibility for a second genesis of life exists, and opinions about the probability range from near zero to near unity. An extra-terrestrial example of life would help answer this question and settle the quandary of whether life is common in the Universe or exceedingly rare. Quantifying the “ordinariness” of life has far reaching philosophical implications that could even inform us about the future of intelligent, technology-wielding life on Earth (Bostrom 2007). Life on Mars, one of our closest planetary neighbors, was considered a forgone conclusion as recently as the mid 20 th century. What else besides an advanced civilization cultivating crops could have been responsible for the telescopically observed network of “canals” scarring its red surface? The “Advanced Martian Civilization” hypothesis had support from preeminent scientists, such as Giovanni Schiaparelli and Percival Lowell, but was relegated to the realm of pseudoscience when data from the Mariner spacecrafts in the 1970s failed to reveal any evidence for such civilizations. There is still no convincing evidence for life on Mars; however, several studies have at least raised one or two eyebrows (Mazur et al. 1978, McKay et al. 1996, Ruff and Farmer 2016). The Mariner missions ushered in the era of modern space exploration at Mars, and with it an earnest search for life. In 1976, shortly after the Mariner missions, the Viking I & II landers delivered “positive” results from their Labeled Release (LR) experiments. Oxidants in the martian regolith are the generally accepted explanation for these results, but some argue that life is the most parsimonious explanation for the Viking data (Levin and Straat 2016). We still do not know if life existed, or exists, on Mars, but Mars was once habitable for the forms of life that took root on early Earth and certain places on Mars likely remain habitable (Davila et al. 2010, Ehlmann et al. 2016). Its potential habitability and proximity to Earth have kept Mars centered in the crosshairs of Astrobiological research for decades. However, icy ocean worlds – Titan, Europa and Enceladus – have garnered increasing attention from the Astrobiology community (National Academies of Sciences and Medicine 2022), partially because any evidence for life on these worlds has a much higher chance of representing a second genesis whereas life on Mars could have potentially originated on Earth (or vice versa). The problems we face in the search for life on Mars today mirror those that confronted Schiaparelli and Lowell: we do not have data of sufficient quality to answer the question definitively. One major difference is that Schiaparelli and Lowell had their prior probability for the expectation of life on Mars set at what m","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135994128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gabrielle Scheffer, Jayne Rattray, Andrew Kingston, Carmen Li, Omid Ardakani, Casey Hubert
Introduction Shale oil reservoirs are hypothesized to be sterile due to the extremely high temperature, pressure and salinity within these formations (Evans et al. 2018). High concentrations of toxic metals also pose challenges that demand specific microbial adaptions (Boyd and Barkay 2012, White and Gadd 1998, Ben Fekih et al. 2018). While some microorganisms are introduced into and are selected for within shale formations during hydraulic fracturing, the possibility that certain microorganisms are pre-existing inhabitants of these formations is less clear. Here, we followed the microbial diversity of input and output fluids injected into a Montney formation shale reservoir to assess the distribution and transport of microbial populations during hydraulic fracturing. Enrichment cultures distinguished various metabolisms in the microbial populations found in different sample types, and adaptations allowing them to colonize such niches. Material and methods Fracturing fluid, drilling muds (3302 m, 3350 m and 3400 m depths), shale cuttings (rinsed from the drillings muds), shale core plugs and produced water samples (12-month period) were sampled from a Montney shale oil reservoir. Microbial community compositions were analyzed by amplicon sequencing. Metal content was analyzed by inductively coupled plasma-mass spectrophotometry. High salinity enrichments at 90°C of the drilling muds or rinsed shale samples were set up in triplicate and amended with glucose and guar gum (a mannose/galactose-based polymer used during hydraulic fracturing). Sugars were measured through spectrophotometric assays. Metagenomic analyses were performed to assess microbial gene content. Results/Discussion Provenance of microorganisms from the Montney shale formation Provenance of microorganisms from the Montney shale formation Input fluids (fracturing fluid, drilling muds) were revealed to be the likely source of most of the microbial diversity. However, some microorganisms were only detected in the subsurface samples. ASVs affiliated with Aurantimonas , Caminicella , BRH-c8a (Family Desulfallas ) and Geotoga exhibited occurrence patterns consistent with being derived from subsurface shale formations. Geotoga has only ever been reported from oil reservoirs (Semenova et al. 2020). Analysis of produced water revealed ASVs from these groups increasing in abundance during hydraulic fracturing operations, suggesting selective pressure from oil reservoir conditions (e.g., toxic metal presence, input of saline water, temperature and pressure fluctuations). Incubations set up from drilling muds showed a preference for glucose while incubations of the rinsed shale cuttings showed a microbial preference for guar gum (i.e., mannose production; Fig. 0), reinforcing the presence of different populations being derived from surface and subsurface samples. Adaptations for life in Montney shale Adaptations for life in Montney shale When considering adaptations of microorganisms for enviro
由于地层中的温度、压力和盐度极高，页岩油储层被认为是无菌的(Evans et al. 2018)。高浓度的有毒金属也带来了挑战，需要特定的微生物适应(Boyd和Barkay 2012, White和Gadd 1998, Ben Fekih等人2018)。虽然在水力压裂过程中，一些微生物被引入页岩地层并被选择，但某些微生物是否已经存在于这些地层中尚不清楚。为了评估水力压裂过程中微生物种群的分布和运移，研究人员跟踪了注入Montney页岩储层的输入液和输出液的微生物多样性。富集培养区分了在不同样品类型中发现的微生物种群的各种代谢，并使其适应于这些生态位。材料和方法从Montney页岩油藏中采集了压裂液、钻井泥浆(深度分别为3302 m、3350 m和3400 m)、页岩岩屑(从钻井泥浆中冲洗出来)、页岩岩心桥塞和采出水样(为期12个月)。通过扩增子测序分析微生物群落组成。采用电感耦合等离子体质分光光度法分析金属含量。在90°C的高盐度条件下，将钻井泥浆或冲洗过的页岩样品分成三份，并用葡萄糖和瓜尔胶(一种用于水力压裂的甘露糖/半乳糖基聚合物)进行修饰。通过分光光度法测定糖的含量。宏基因组分析评估微生物基因含量。输入流体(压裂液、钻井泥浆)可能是大部分微生物多样性的来源。然而，一些微生物仅在地下样品中检测到。与Aurantimonas、Caminicella、BRH-c8a (Family Desulfallas)和Geotoga相关的asv显示出与地下页岩地层相一致的产状模式。Geotoga仅在油藏中被报道过(Semenova et al. 2020)。对采出水的分析显示，在水力压裂作业中，这些组的asv数量增加，这表明油藏条件(例如，有毒金属的存在、盐水的输入、温度和压力波动)具有选择性压力。从钻井泥浆中建立的孵育物显示出对葡萄糖的偏好，而冲洗过的页岩岩屑的孵育物显示出对瓜尔胶(即甘露糖生产)的微生物偏好;图0)，强化了来自地表和地下样本的不同种群的存在。在考虑微生物对油藏环境条件的适应时，需要注意砷、镉和汞等有毒金属的存在。在为期28天的页岩微生物富集和12个月的采出水时间过程分析中，发现这三种金属的含量随时间而变化。宏基因组学揭示了页岩微生物组中所有三种金属的内化和代谢的各种基因(即砷酸盐还原酶，亚砷酸盐转运蛋白，金属硫蛋白，汞还原酶)。总之，本研究的结果表明，页岩储层因此可能不是无菌环境，宿主微生物能够应对重大扰动。
{"title":"The provenance of microorganisms adapted to extreme salinity, extreme temperature, and toxic metals within the Montney shale formation.","authors":"Gabrielle Scheffer, Jayne Rattray, Andrew Kingston, Carmen Li, Omid Ardakani, Casey Hubert","doi":"10.3897/aca.6.e108166","DOIUrl":"https://doi.org/10.3897/aca.6.e108166","url":null,"abstract":"Introduction Shale oil reservoirs are hypothesized to be sterile due to the extremely high temperature, pressure and salinity within these formations (Evans et al. 2018). High concentrations of toxic metals also pose challenges that demand specific microbial adaptions (Boyd and Barkay 2012, White and Gadd 1998, Ben Fekih et al. 2018). While some microorganisms are introduced into and are selected for within shale formations during hydraulic fracturing, the possibility that certain microorganisms are pre-existing inhabitants of these formations is less clear. Here, we followed the microbial diversity of input and output fluids injected into a Montney formation shale reservoir to assess the distribution and transport of microbial populations during hydraulic fracturing. Enrichment cultures distinguished various metabolisms in the microbial populations found in different sample types, and adaptations allowing them to colonize such niches. Material and methods Fracturing fluid, drilling muds (3302 m, 3350 m and 3400 m depths), shale cuttings (rinsed from the drillings muds), shale core plugs and produced water samples (12-month period) were sampled from a Montney shale oil reservoir. Microbial community compositions were analyzed by amplicon sequencing. Metal content was analyzed by inductively coupled plasma-mass spectrophotometry. High salinity enrichments at 90°C of the drilling muds or rinsed shale samples were set up in triplicate and amended with glucose and guar gum (a mannose/galactose-based polymer used during hydraulic fracturing). Sugars were measured through spectrophotometric assays. Metagenomic analyses were performed to assess microbial gene content. Results/Discussion Provenance of microorganisms from the Montney shale formation Provenance of microorganisms from the Montney shale formation Input fluids (fracturing fluid, drilling muds) were revealed to be the likely source of most of the microbial diversity. However, some microorganisms were only detected in the subsurface samples. ASVs affiliated with Aurantimonas , Caminicella , BRH-c8a (Family Desulfallas ) and Geotoga exhibited occurrence patterns consistent with being derived from subsurface shale formations. Geotoga has only ever been reported from oil reservoirs (Semenova et al. 2020). Analysis of produced water revealed ASVs from these groups increasing in abundance during hydraulic fracturing operations, suggesting selective pressure from oil reservoir conditions (e.g., toxic metal presence, input of saline water, temperature and pressure fluctuations). Incubations set up from drilling muds showed a preference for glucose while incubations of the rinsed shale cuttings showed a microbial preference for guar gum (i.e., mannose production; Fig. 0), reinforcing the presence of different populations being derived from surface and subsurface samples. Adaptations for life in Montney shale Adaptations for life in Montney shale When considering adaptations of microorganisms for enviro","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135996104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
John Spear, Sasha Robinson, Paul Slayback, Patrick Thieringer, Carmen Villarruel
Fve miles west of Cody, Wyoming and ~25 miles east of Yellowstone National Park lies the Shoshone Canyon Conduit Cave (Fig. 1, Suppl. material 1). Bisecting Cedar Mountain, an irrigation tunnel built by the Bureau of Reclamation (BoR), managed by the Heart Mountain Irrigation District, delivers water from the BoR Buffalo Bill Reservoir to more than 30,000 acres of irrigated lands in and around Cody. During the construction of that tunnel in the late 1940’s, a cave was discovered and the tunnel was made to travel though the cave with only light disturbance to the cave. The cave can only be accessed with permission in the non-irrigation time of year. The cave is rich in sulfides and sulfur deposits with unique speleothems. To date, we have conducted a preliminary geobiological survey of the geochemistry, microbiology and mineralogy of this sulfur cave on its speleothems, mineral deposits and waters. Sampled waters, of which there is little, were all highly acidic (pH < 2). Microbiologically, an analysis of microbial communities present in approximately 25 sample locations (Fig. 1) to answer the question of—who is there?—was conducted via small subunit ribosomal 16S rRNA gene (for Bacteria and Archaea) and 18S rRNA (for Eukarya) analyses, prepared using a polymerase chain reaction (PCR) primer-pair that allows for the even amplification of all three domains of life. All samples were relatively low in biomass and resultant community analysis indicates a variety of Bacteria and Archaea phyla are represented with a dominance of known sulfur metabolizers. Mineralogically, petrography reveals a variety of crystal growth and habit in this sulfur-dominated, calcium carbonate-driven karstic ecosystem. X-ray diffraction analysis (XRD) was used to better determine the kinds and extant of mineral morphotypes and were surprisingly variable. The Shoshone Canyon Conduit Cave is a most intriguing sulfur cave to reveal what is known of the geobiology of sulfur caves in the Rocky Mountain Region. Findings from this work will likely apply to other cave systems such as Villa Luz (Mexico) and the Frasassi system (Italy). Finally, to learn about the Cedar Mountain Caves will inform on how either or both the National Park Service (NPS) and Bureau of Land Management (BLM) may better manage them as a meaningful component of the Greater Yellowstone Ecosystem.
{"title":"The Shoshone Canyon Conduit Cave: A Greater Yellowstone Ecosystem Sulfur Cave","authors":"John Spear, Sasha Robinson, Paul Slayback, Patrick Thieringer, Carmen Villarruel","doi":"10.3897/aca.6.e108455","DOIUrl":"https://doi.org/10.3897/aca.6.e108455","url":null,"abstract":"Fve miles west of Cody, Wyoming and ~25 miles east of Yellowstone National Park lies the Shoshone Canyon Conduit Cave (Fig. 1, Suppl. material 1). Bisecting Cedar Mountain, an irrigation tunnel built by the Bureau of Reclamation (BoR), managed by the Heart Mountain Irrigation District, delivers water from the BoR Buffalo Bill Reservoir to more than 30,000 acres of irrigated lands in and around Cody. During the construction of that tunnel in the late 1940’s, a cave was discovered and the tunnel was made to travel though the cave with only light disturbance to the cave. The cave can only be accessed with permission in the non-irrigation time of year. The cave is rich in sulfides and sulfur deposits with unique speleothems. To date, we have conducted a preliminary geobiological survey of the geochemistry, microbiology and mineralogy of this sulfur cave on its speleothems, mineral deposits and waters. Sampled waters, of which there is little, were all highly acidic (pH &lt; 2). Microbiologically, an analysis of microbial communities present in approximately 25 sample locations (Fig. 1) to answer the question of—who is there?—was conducted via small subunit ribosomal 16S rRNA gene (for Bacteria and Archaea) and 18S rRNA (for Eukarya) analyses, prepared using a polymerase chain reaction (PCR) primer-pair that allows for the even amplification of all three domains of life. All samples were relatively low in biomass and resultant community analysis indicates a variety of Bacteria and Archaea phyla are represented with a dominance of known sulfur metabolizers. Mineralogically, petrography reveals a variety of crystal growth and habit in this sulfur-dominated, calcium carbonate-driven karstic ecosystem. X-ray diffraction analysis (XRD) was used to better determine the kinds and extant of mineral morphotypes and were surprisingly variable. The Shoshone Canyon Conduit Cave is a most intriguing sulfur cave to reveal what is known of the geobiology of sulfur caves in the Rocky Mountain Region. Findings from this work will likely apply to other cave systems such as Villa Luz (Mexico) and the Frasassi system (Italy). Finally, to learn about the Cedar Mountain Caves will inform on how either or both the National Park Service (NPS) and Bureau of Land Management (BLM) may better manage them as a meaningful component of the Greater Yellowstone Ecosystem.","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136032505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Denise Akob, Mitra Kashani, Mark Engle, Douglas Kent, Terry Gregston, Isabelle Cozzarelli, Adam Mumford, Matthew Varonka, Cassandra Harris
The Permian Basin, underlying New Mexico and Texas, is one of the most productive oil and gas (OG) provinces in the United States. Oil and gas production yields large volumes of wastewater with complex chemistries. The environmental health risks posed by these OG wastewaters are not well understood, particularly in the case of accidental or intentional releases. Starting in November 2017, 39 illegal dumps of OG wastewater were identified in southeastern New Mexico that released approximately 6.4x10 5 liters of fluid onto desert soils. To evaluate the impacts of these releases on soils, we analyzed changes in soil geochemistry and microbial community composition by comparing soils from within OG wastewater dump-affected zones to corresponding unaffected zones with no known releases. We observed significant (p<0.01) changes in soil geochemistry for all dump-affected samples compared to controls, reflecting the residual salts and hydrocarbons left behind by the OG-wastewater release (e.g., enriched in sodium (Na), chloride (Cl), and bromide (Br)). Illumina 16S iTag sequencing revealed significant (p<0.01) differences in microbial community structure between dump and control zones. Furthermore, soils from dump areas had significantly (p<0.01) lower alpha diversity and exhibited differences in phylogenetic composition. Dump-affected soil samples showed an increase in halophilic and halotolerant taxa, such as members of the Marinobacteraceae, Halomonadaceae, and Halobacteroidaceae, suggesting that the high salinity of the dumped OG wastewater exerted a selective pressure on microbial communities. Taxa related to known hydrocarbon-degrading organisms, e.g., Marinobacter, Salegentibacter, Chromohalobacter , and Alcanivorax , were also detected in the dump-affected soil-sample communities. The microbial communities in control soils were dominated by taxa ubiquitous in, and well adapted to, arid and nutrient-deprived soil environments including photosynthetic Cyanobacteria, hydrogen-oxidizing Actinobacteria and Acidobacteria, and nitrogen-fixing Alphaproteobacteria. This study demonstrated that OG-wastewater dumps can lead to shifts in microbial community composition and function towards salt- and hydrocarbon-tolerant taxa that are not typically found in desert soils, thus altering the impacted dryland soil ecosystem. Loss of key microbial taxa, such as those that increase arid soil fertility, or promote plant health, could result in cascading affects to myriad ecosystem services such as loss of flora. Further studies are needed to explore the potential for using halophilic and hydrocarbon-degrading taxa to bioremediate OG-wastewater affected lands.
{"title":"Illegal Dumping of Oil and Gas Wastewaters Alters Semi-Arid Soil Microbial Communities","authors":"Denise Akob, Mitra Kashani, Mark Engle, Douglas Kent, Terry Gregston, Isabelle Cozzarelli, Adam Mumford, Matthew Varonka, Cassandra Harris","doi":"10.3897/aca.6.e109202","DOIUrl":"https://doi.org/10.3897/aca.6.e109202","url":null,"abstract":"The Permian Basin, underlying New Mexico and Texas, is one of the most productive oil and gas (OG) provinces in the United States. Oil and gas production yields large volumes of wastewater with complex chemistries. The environmental health risks posed by these OG wastewaters are not well understood, particularly in the case of accidental or intentional releases. Starting in November 2017, 39 illegal dumps of OG wastewater were identified in southeastern New Mexico that released approximately 6.4x10 5 liters of fluid onto desert soils. To evaluate the impacts of these releases on soils, we analyzed changes in soil geochemistry and microbial community composition by comparing soils from within OG wastewater dump-affected zones to corresponding unaffected zones with no known releases. We observed significant (p&lt;0.01) changes in soil geochemistry for all dump-affected samples compared to controls, reflecting the residual salts and hydrocarbons left behind by the OG-wastewater release (e.g., enriched in sodium (Na), chloride (Cl), and bromide (Br)). Illumina 16S iTag sequencing revealed significant (p&lt;0.01) differences in microbial community structure between dump and control zones. Furthermore, soils from dump areas had significantly (p&lt;0.01) lower alpha diversity and exhibited differences in phylogenetic composition. Dump-affected soil samples showed an increase in halophilic and halotolerant taxa, such as members of the Marinobacteraceae, Halomonadaceae, and Halobacteroidaceae, suggesting that the high salinity of the dumped OG wastewater exerted a selective pressure on microbial communities. Taxa related to known hydrocarbon-degrading organisms, e.g., Marinobacter, Salegentibacter, Chromohalobacter , and Alcanivorax , were also detected in the dump-affected soil-sample communities. The microbial communities in control soils were dominated by taxa ubiquitous in, and well adapted to, arid and nutrient-deprived soil environments including photosynthetic Cyanobacteria, hydrogen-oxidizing Actinobacteria and Acidobacteria, and nitrogen-fixing Alphaproteobacteria. This study demonstrated that OG-wastewater dumps can lead to shifts in microbial community composition and function towards salt- and hydrocarbon-tolerant taxa that are not typically found in desert soils, thus altering the impacted dryland soil ecosystem. Loss of key microbial taxa, such as those that increase arid soil fertility, or promote plant health, could result in cascading affects to myriad ecosystem services such as loss of flora. Further studies are needed to explore the potential for using halophilic and hydrocarbon-degrading taxa to bioremediate OG-wastewater affected lands.","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136032526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Denise Akob, John Sutton, Timothy Bushman, Shaun Baesman, Edina Klein, Yesha Shrestha, Robert Andrews, Janna Fierst, Max Kolton, Sara Gushgari-Doyle, Ronald Oremland, John Freeman
Acetylene (C 2 H 2 ) is a trace constituent of Earth’s modern atmosphere and is used by acetylenotrophic microorganisms as their sole carbon and energy source (Akob et al. 2018) Acetylenotrophs hydrate acetylene through a reaction catalyzed by acetylene hydratase, which is a heterogeneous class of enzymes. As of 2018, there were 15 known strains of acetylenotrophs including aerobic species affiliated with the Actinobacteria, and Firmicutes and anaerobic species affiliated with the Desulfobacterota. However, we hypothesized that there was an unknown diversity of acetylenotrophs in nature. We recently expanded the known distribution of acetylenotrophs via the isolation of the aerobic acetylenotroph, Bradyrhizobium sp. strain I71, from trichloroethylene (TCE)-contaminated soils (Akob et al. 2022). Strain I71 is a member of the class Alphaproteobacteria, and this is the first observation of an aerobic acetylenotroph in the Proteobacteria phylum. The isolate grows via heterotrophic and acetylenotrophic metabolism, and is diazotrophic, capable of nitrogen fixation. Acetylenotrophy and nitrogen fixation are the only two enzymatic reactions known to transform acetylene, and this is only the second isolate known to carry out both reactions (Akob et al. 2017, Baesman et al. 2019). Members of Bradyrhizobium are well studied for their abilities to improve plant health and increase crop yields by providing bioavailable nitrogen. The unique capability of Bradyrhizobium sp. strain I71 to utilize acetylene may increase the genus’ economic impact beyond agriculture as acetylenotrophy is closely linked to bioremediation of chlorinated contaminants (Mao et al. 2017, Gushgari-Doyle et al. 2021). Based on genome, cultivation, and protein prediction analysis, the ability to consume acetylene is likely not widespread within the genus Bradyrhizobium . These findings suggest that the suite of phenotypic capabilities of strain I71 may be unique and make it a good candidate for further study in several research avenues such as contaminant biodegradation and nutrient cycling.
乙炔(c2h 2)是地球现代大气中的微量成分，被乙炔营养微生物用作其唯一的碳和能量来源(Akob et al. 2018)。乙炔营养微生物通过乙炔水合酶催化的反应水合乙炔，乙炔水合酶是一种异质酶。截至2018年，已知有15种乙酰营养菌，包括与放线菌门相关的好氧菌，以及与脱硫菌门相关的厚壁菌门和厌氧菌。然而，我们假设自然界中存在未知的乙酰氨基营养体多样性。我们最近通过从三氯乙烯(TCE)污染的土壤中分离出需氧乙酰营养菌，缓生根瘤菌菌株I71，扩大了已知的乙酰营养菌分布(Akob et al. 2022)。菌株I71是α变形菌纲的一员，这是在变形菌门中首次观察到需氧乙酰营养菌。分离物通过异养和乙酰营养代谢生长，重氮营养，能够固定氮。乙酰化和固氮是已知仅有的两种转化乙炔的酶促反应，这是已知的第二种同时进行这两种反应的分离物(Akob et al. 2017, Baesman et al. 2019)。缓生根瘤菌成员通过提供生物可利用氮来改善植物健康和提高作物产量的能力得到了很好的研究。基于基因组、培养和蛋白质预测分析，消耗乙炔的能力在慢生根瘤菌属中可能并不普遍。这些发现表明，菌株I71的表型能力可能是独特的，并使其在污染物生物降解和养分循环等研究途径中成为进一步研究的良好候选者。
{"title":"Acetylenotrophic and Diazotrophic Bradyrhizobium sp. Strain I71 from Trichloroethylene-Contaminated Soils","authors":"Denise Akob, John Sutton, Timothy Bushman, Shaun Baesman, Edina Klein, Yesha Shrestha, Robert Andrews, Janna Fierst, Max Kolton, Sara Gushgari-Doyle, Ronald Oremland, John Freeman","doi":"10.3897/aca.6.e109201","DOIUrl":"https://doi.org/10.3897/aca.6.e109201","url":null,"abstract":"Acetylene (C 2 H 2 ) is a trace constituent of Earth’s modern atmosphere and is used by acetylenotrophic microorganisms as their sole carbon and energy source (Akob et al. 2018) Acetylenotrophs hydrate acetylene through a reaction catalyzed by acetylene hydratase, which is a heterogeneous class of enzymes. As of 2018, there were 15 known strains of acetylenotrophs including aerobic species affiliated with the Actinobacteria, and Firmicutes and anaerobic species affiliated with the Desulfobacterota. However, we hypothesized that there was an unknown diversity of acetylenotrophs in nature. We recently expanded the known distribution of acetylenotrophs via the isolation of the aerobic acetylenotroph, Bradyrhizobium sp. strain I71, from trichloroethylene (TCE)-contaminated soils (Akob et al. 2022). Strain I71 is a member of the class Alphaproteobacteria, and this is the first observation of an aerobic acetylenotroph in the Proteobacteria phylum. The isolate grows via heterotrophic and acetylenotrophic metabolism, and is diazotrophic, capable of nitrogen fixation. Acetylenotrophy and nitrogen fixation are the only two enzymatic reactions known to transform acetylene, and this is only the second isolate known to carry out both reactions (Akob et al. 2017, Baesman et al. 2019). Members of Bradyrhizobium are well studied for their abilities to improve plant health and increase crop yields by providing bioavailable nitrogen. The unique capability of Bradyrhizobium sp. strain I71 to utilize acetylene may increase the genus’ economic impact beyond agriculture as acetylenotrophy is closely linked to bioremediation of chlorinated contaminants (Mao et al. 2017, Gushgari-Doyle et al. 2021). Based on genome, cultivation, and protein prediction analysis, the ability to consume acetylene is likely not widespread within the genus Bradyrhizobium . These findings suggest that the suite of phenotypic capabilities of strain I71 may be unique and make it a good candidate for further study in several research avenues such as contaminant biodegradation and nutrient cycling.","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136033006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuhao Li, Lingyi Tang, Daniel Alessi, Janice Kenney, Murray Gingras, Kurt Konhauser
Precambrian banded iron formations (BIF) are iron- and silica-rich chemical sedimentary rocks that are commonly used as paleo-redox proxies for Archean and Paleoproterozoic seawater geochemistry. At the onset of the Great Oxidation Event (herein GOE) around 2.4 Ga, cyanobacteria flourished with increasing nutrient fluxes due to oxidative weathering on land. In turn, this led to increased primary productivity that facilitated the permanent shift from a reducing Earth atmosphere to an oxidizing one. Interestingly, the duration of GOE also overlapped with one of the most prolific periods of BIF deposition.It is widely accepted that cyanobacteria were likely responsible for BIF formation during the GOE. Oxidation of dissolved Fe(II) by oxygen produced from cyanobacteria forms a metastable and amorphous mineral phase ferrihydrite, Fe(OH) 3 . As an essential component in both ancient BIF deposits and various modern ecosystems, the surface reactivity of ferrihydrite has been extensively studied under different conditions (i.e., pH and ionic strengths). Not only are the highly reactive surfaces of ferrihydrite particles important shuttles for trace element transport from the water column to the sediment pile, but previous studies have also demonstrated that cyanobacterial cells and ferrihydrite tend to aggregate at seawater pH. This means that ferrihydrite was also a vector for the transport of organic carbon to the seafloor. However, a complicating issue is how co-ions affect the surface reactivity of ferrihydrite, specifically dissolved silica which was abundant in ancient seawater. Although previous studies have demonstrated that silica can passivate the surface reactivity of ferrihydrite, what remains unclear is how silica impacts ferrihydrite-biomass aggregation. To fill this knowledge gap, we formed both silica-spiked ferrihydrite and cyanobacteria-ferrihydrite aggregates in situ and subsequently conducted empirical potentiometric acid-base titrations and Cd adsorption experiments on the fresh aggregate samples at three different ionic strengths (0.56 M, 0.1 M and 0.01 M). We minimized sample processing (i.e., drying and powdering) to a simple washing step, in which the aggregate pellets remained hydrated to avoid any mineral transformation thus altering their true surface reactivity in seawater. Experimental results were then fitted with non-electrostatic model to predict both surface charges and metal-adsorption behavior of ferrihydrite aggregates. Different from previous surface-complexation modelling studies, here we used a novel and more powerful modelling program called Phreefit. It utilizes the global optimization algorithms instead of more commonly used Newton-Raphson method in FITEQL program, which is often too limited for precisely modelling complex systems such as the two samples in this study. Furthermore, we also measured the surface charges of both samples over the pH range from 3 to 9 on a Malvern Zetasizer and characterized the surf
前寒武纪带状铁组(BIF)是一种富铁和富硅的化学沉积岩，通常被用作太古宙和古元古代海水地球化学的古氧化还原指标。在2.4 Ga左右的大氧化事件(GOE)开始时，由于陆地上的氧化风化，蓝藻随着营养通量的增加而繁盛。反过来，这导致初级生产力的增加，促进了地球大气层从还原到氧化的永久转变。有趣的是，GOE的持续时间也与BIF沉积最丰富的时期之一重叠。人们普遍认为蓝藻可能是GOE期间BIF形成的原因。由蓝藻产生的氧氧化溶解的铁(II)形成亚稳和无定形矿物相铁水合物Fe(OH) 3。作为古代BIF沉积物和各种现代生态系统的重要组成部分，水合铁在不同条件下(即pH和离子强度)的表面反应性已被广泛研究。水合铁颗粒的高活性表面不仅是微量元素从水柱向沉积物堆运输的重要载体，而且先前的研究也表明，蓝藻细胞和水合铁在海水ph下倾向于聚集。这意味着水合铁也是有机碳向海底运输的载体。然而，一个复杂的问题是，共离子如何影响水合铁的表面反应性，特别是在古代海水中丰富的溶解二氧化硅。虽然先前的研究已经证明二氧化硅可以钝化水合铁的表面反应性，但二氧化硅如何影响水合铁-生物质聚集仍不清楚。为了填补这一知识空白，我们在原位形成了硅尖铁水合铁和蓝藻水合铁水合铁聚集体，随后在三种不同离子强度(0.56 M, 0.1 M和0.01 M)下对新鲜聚集体样品进行了经验电位酸碱滴定和Cd吸附实验。在这种情况下，集料颗粒保持水合状态，以避免任何矿物转化，从而改变其在海水中的真实表面反应性。用非静电模型拟合实验结果，预测了水合铁聚集体的表面电荷和金属吸附行为。与以往的表面络合模型研究不同，这里我们使用了一种新颖且更强大的建模程序，称为Phreefit。在FITEQL程序中，它采用了全局优化算法，而不是更常用的Newton-Raphson方法。对于像本研究中的两个样本这样的复杂系统的精确建模，Newton-Raphson方法往往过于有限。此外，我们还在Malvern Zetasizer上测量了两种样品在pH值3至9范围内的表面电荷，并通过傅里叶变换红外光谱表征了表面官能团，以帮助我们解释实验数据。初步结果表明，蓝藻-水合铁聚集体的形成主要是由于离子桥接。蓝藻细胞可能促进了溶解二氧化硅的沉淀。滴定和Cd吸附实验的结果表明，两种富硅水合铁蓝藻-水合铁聚集体对微量元素的表面反应性和吸附能力不同，可能是由于位点堵塞。当考虑太古宙海水pH值为6 ~ 8时，这一区别尤为突出。这一差异表明，生物成因的水合铁聚集体不表现出加性表面反应性，这与以往类似的研究一致。我们的综合结果对于准确预测微量元素在团聚体表面的吸附，并最终理解沉积岩中用于重建前寒武纪海洋化学的微量元素档案至关重要。
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Hiba Aoid, Richard Léveillé, Peter Douglas, Myriam Lemelin, Marie-Claude Williamson
If past life ever existed on Mars, what are the multiple ways it could have been preserved in the Martian geological record? This crucial question is becoming especially relevant the more we uncover about the planet’s ancient wet history. Different acidic and sulfur rich analog environments have been proposed that are comparable to the alteration environments of iron oxides and sulfate minerals on Mars. However, some authors have hypothesized that these past Martian environments might have been cold and semi-dry, similar to polar regions on Earth. As part of the T-MARS team, we studied reactive gossans in the Canadian High Arctic, on Axel Heiberg Island, as an analog environment to similar deposits on Mars. We hypothesized that n-alkane lipids could potentially be an important form of molecular fossils entombed in varying mineral assemblages of sulphates, iron oxides, and phyllosilicates in Arctic gossans, because of their excellent preservation potential relative to most other forms of organic molecules. To determine the preservation potential of lipids in mineralogically varying acidic sulfur rich gossan deposits, this study extracted and quantified n-alkane biomarkers from three different Arctic gossans with gas chromatography–mass spectrometry (GC-MS). Total organic carbon, pH, and mineralogy were also determined. Organic matter was found to be very low in all samples (<1% wt.%). N-alkane analysis also revealed preserved even-over-odd distribution patterns in short chain n-alkanes, most likely from a microbial source, along with evidence for long-chain n-alkanes with odd-over-even distribution from higher plant sources. The presence of these unique chemical biosignatures in low organic, highly acidic, and sulfur rich Mars analog gossans of varying maturity provides evidence that sulfur deposits linked to paleo hydrothermal systems on Mars can be promising targets for preserved organic biosignatures, specifically lipid n-alkanes. The significant diversity in biosignature patterns across samples of varying mineralogy, pH, and oxidation levels within each gossan suggests that n-alkane preservation varies on a small scale in these environments. These factors alone do not definitively account for the variability of n-alkane concentrations and distributions in this study, and additional investigations of these and other influencing factors are needed to determine which specific targets to choose for biosignature search on Mars in future space missions. This exploratory study provides novel insights into the lipid biosignature content in high Arctic Mars analogue gossan deposits.
{"title":"N-Alkane Biosignatures in a High Arctic Mars Analogue Gossan Deposit","authors":"Hiba Aoid, Richard Léveillé, Peter Douglas, Myriam Lemelin, Marie-Claude Williamson","doi":"10.3897/aca.6.e108199","DOIUrl":"https://doi.org/10.3897/aca.6.e108199","url":null,"abstract":"If past life ever existed on Mars, what are the multiple ways it could have been preserved in the Martian geological record? This crucial question is becoming especially relevant the more we uncover about the planet’s ancient wet history. Different acidic and sulfur rich analog environments have been proposed that are comparable to the alteration environments of iron oxides and sulfate minerals on Mars. However, some authors have hypothesized that these past Martian environments might have been cold and semi-dry, similar to polar regions on Earth. As part of the T-MARS team, we studied reactive gossans in the Canadian High Arctic, on Axel Heiberg Island, as an analog environment to similar deposits on Mars. We hypothesized that n-alkane lipids could potentially be an important form of molecular fossils entombed in varying mineral assemblages of sulphates, iron oxides, and phyllosilicates in Arctic gossans, because of their excellent preservation potential relative to most other forms of organic molecules. To determine the preservation potential of lipids in mineralogically varying acidic sulfur rich gossan deposits, this study extracted and quantified n-alkane biomarkers from three different Arctic gossans with gas chromatography–mass spectrometry (GC-MS). Total organic carbon, pH, and mineralogy were also determined. Organic matter was found to be very low in all samples (&lt;1% wt.%). N-alkane analysis also revealed preserved even-over-odd distribution patterns in short chain n-alkanes, most likely from a microbial source, along with evidence for long-chain n-alkanes with odd-over-even distribution from higher plant sources. The presence of these unique chemical biosignatures in low organic, highly acidic, and sulfur rich Mars analog gossans of varying maturity provides evidence that sulfur deposits linked to paleo hydrothermal systems on Mars can be promising targets for preserved organic biosignatures, specifically lipid n-alkanes. The significant diversity in biosignature patterns across samples of varying mineralogy, pH, and oxidation levels within each gossan suggests that n-alkane preservation varies on a small scale in these environments. These factors alone do not definitively account for the variability of n-alkane concentrations and distributions in this study, and additional investigations of these and other influencing factors are needed to determine which specific targets to choose for biosignature search on Mars in future space missions. This exploratory study provides novel insights into the lipid biosignature content in high Arctic Mars analogue gossan deposits.","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136033430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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