Geobiology最新文献

{"title":"Impact Crater Hydrothermal Systems Support Rapid Microbial Enrichment and Diverse Metabolic Potential","authors":"Sabrina M. C. Hardy,&nbsp;Emily J. Aguilar-Pine,&nbsp;Sean Gulick,&nbsp;Alaa Ahmad,&nbsp;Brett J. Baker,&nbsp;Nathalie Scott,&nbsp;Georgina Aitolo,&nbsp;Naomi Felton,&nbsp;Charles S. Cockell","doi":"10.1111/gbi.70070","DOIUrl":"https://doi.org/10.1111/gbi.70070","url":null,"abstract":"<p>Impact crater hydrothermal systems, formed after asteroid and comet impacts, have been proposed as promising habitats for life on early Earth and as key targets in the search for life on planetary bodies such as Mars, since they provide liquid water and active geochemical turnover. Because no newly formed impact structures exist on Earth, studies of microbial establishment in impact-crater hydrothermal systems have largely relied on the direct observation of fossil microbial life or its isotopic signatures. To address this limitation, we established simulated microcosm hydrothermal systems in the laboratory using melt-bearing impact breccia (suevite) from the Ries impact structure, Germany, and temperate soils. Within weeks, these systems hosted taxonomically diverse communities, with broad metabolic potential, partitioned among oxidized impact glass, endolithic suevite habitats, and sedimentary environments. Dominant taxa included thermophiles from primarily heterotrophic lineages (e.g., <i>Meiothermus</i> and <i>Aneurinibacillus</i> spp.), as well as lineages with potentially chemolithotrophic metabolisms (e.g., <i>Brockia</i> spp.). Metagenomic annotations identified genes associated with methane, iron, and sulfur cycling, including sulfate-reduction, indicating metabolic potential for biogeochemically relevant processes under hydrothermal conditions. These results show that impact-generated hydrothermal systems can rapidly support diverse thermophilic microbial communities with habitat-specific community structure and metabolic potential, supporting their relevance as analogue environments for studying early microbial establishment and biosignature formation in planetary impact settings.</p>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"24 6","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gbi.70070","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149206099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exceptional Chitin Preservation Driven by Early-Stage Silicification in Mesozoic Freshwater Environments","authors":"Taro Yoshimura,&nbsp;Kentaro Nakayama,&nbsp;Kaito Asato,&nbsp;Yoshikazu Noda,&nbsp;Takenori Sasaki","doi":"10.1111/gbi.70067","DOIUrl":"10.1111/gbi.70067","url":null,"abstract":"<p>Chitin is a fundamental structural biopolymer, yet its fossil record is predominantly biased towards marine Lagerstätten or specific stagnant non-marine settings, leaving its stability in dynamic continental environments poorly understood. Here, we report the molecular preservation of indigenous chitin within the shells of the bivalve <i>Nakamuranaia soni</i> from the Lower Cretaceous Kitadani Formation, Japan—a renowned dinosaur-bearing fluvial succession. While Paleozoic and Jurassic records of chitin exist for arthropods and brackish gastropods, our findings represent one of the earliest direct records of chitinous biopolymers within a strictly freshwater fluvial Lophotrochozoan. High-resolution FE-SEM and histochemical staining (Calcofluor White and Congo Red) revealed exceptionally preserved periostracal honeycomb-like templates, morphologically and chemically congruent with extant unionids. FT-IR spectroscopy confirmed diagnostic polysaccharide backbone linkages and amide modes matching reference <i>β</i>-chitin, while host-rock analysis (negative control) established the indigenous nature of these organics. Decalcification experiments yielded a rigid silica–chitin hybrid framework, suggesting that early-stage silicification acted as a ‘taphonomic shield’. We propose that rapid mineralisation, driven by volcaniclastic-rich hydrochemistry, encapsulated the microfibrils, providing both steric hindrance, and chemical stabilisation. This discovery demonstrates that authigenic silicification can mitigate the degradative effects of freshwater diagenesis, significantly expanding the spatial and molecular boundaries of the terrestrial fossil record.</p>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"24 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gbi.70067","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149134362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biomarker Evidence for Photic-Zone Euxinia and Oxygen-Bearing Geolipids in Miocene Sediments of the Valjevo-Mionica Basin","authors":"Aleksandra Šajnović,&nbsp;Nikola Burazer,&nbsp;Vladimir Simić,&nbsp;Branimir Jovančićević","doi":"10.1111/gbi.70069","DOIUrl":"10.1111/gbi.70069","url":null,"abstract":"<div>\u0000 \u0000 <p>This study investigates the occurrence of aromatic carotenoids and oxygen-bearing geolipids, namely γ-<i>n</i>-alkyl-γ-butyrolactones, δ-<i>n</i>-alkyl-δ-valerolactones, and γ-isoprenoid-alkyl-γ-butyrolactones, in Miocene sediments from the Valjevo-Mionica Basin (Serbia), from the 360–400 m depth interval. Soluble organic matter was analyzed by gas chromatography–mass spectrometry (GC–MS), and the biomarker data were integrated with previously published geological, mineralogical, and geochemical data to reconstruct the depositional environment. Aromatic carotenoid distributions provide evidence for photic-zone euxinia (PZE) and indicate changes in microbial community composition within the stratified lacustrine system. Isorenieratane and β-isorenieratane predominance in the 360–370 m interval is most consistent with strongly stratified PZE conditions favoring low-light-adapted green sulfur bacteria. In contrast, the 370–380 m interval records a greater contribution from purple sulfur bacteria, as indicated by abundant okenane, whereas the prevalence of renierapurpurane in the 380–400 m interval, together with elevated Li, Mg, and B concentrations and clay minerals, is compatible with a significant cyanobacterial contribution under alkaline, restricted-basin conditions. The occurrence of γ- and δ-lactones is consistent with anoxic, saline depositional environments characterized by limited bioturbation and active microbial transformation of organic matter, with subsequent cyclization and dehydration occurring during early diagenesis. Mass spectral fragmentation patterns indicate the presence of a previously undescribed compound (molecular mass ~568 Da) within the 370–390 m interval, for which intramolecular lactonization of a torularhodin-derived precursor is proposed as one plausible formation pathway. These findings expand the diversity of biomarkers associated with PZE and contribute to paleoenvironmental reconstructions of paleolakes, which represent sensitive archives of global paleoclimate change.</p>\u0000 </div>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"24 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149101437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uranium Isotope Evidence for Persistent Global Ocean Anoxia Across the Ediacaran–Cambrian Transition in Siberia","authors":"Andrew D. Doerrler,&nbsp;Tian Gan,&nbsp;Geoffrey J. Gilleaudeau,&nbsp;Matthew G. Pedersen,&nbsp;Natalia Bykova,&nbsp;Vasiliy Marusin,&nbsp;Natalia A. Ivanova,&nbsp;Boris Kochnev,&nbsp;Dimitriy V. Grazhdankin,&nbsp;Karel Kletetschka,&nbsp;Alan J. Kaufman","doi":"10.1111/gbi.70066","DOIUrl":"https://doi.org/10.1111/gbi.70066","url":null,"abstract":"<p>The enigmatic Ediacara biota represents Earth's earliest example of macroscopic, complex life, yet the driving forces promoting their mid-Ediacaran evolution and subsequent extinction across the Ediacaran–Cambrian boundary remain speculative. If these were true animals requiring oxygen for aerobic respiration, their rise has often been linked to dramatic changes in the redox state of seawater. Their disappearance from the fossil record—whether gradual or abrupt—and replacement with Cambrian animals has similarly been linked to redox fluctuations, suggesting an environmental driver, or alternatively to biological factors such as predation of the predominantly soft-bodied organisms and bioturbation that disrupted the microbial mats in which they were intimately associated. Insofar as Ediacara extinction is linked to a major perturbation of the global carbon cycle (the BAsal Cambrian carbon isotope Excursion or BACE), an environmental driver seems likely. On the one hand, their demise might reflect the spread of seawater anoxia if these organisms had aerobic metabolisms, but on the other, widespread ocean oxygenation may have been the proximal cause of their extinction and the BACE event if the biota was tolerant and even thrived under low-oxygen conditions. To test between the two alternative redox scenarios, we present a suite of geochemical data including uranium isotopes (δ²³⁸U) from carbonate and evaporite-rich successions that span the BACE on the Siberian Platform. Like conditions before and after the event, consistently low δ²³⁸U values from both sections (median reconstructed seawater δ²³⁸U = −0.74‰ to −0.79‰) suggest that widespread ocean anoxia persisted across the Ediacaran–Cambrian transition. The integrated data indicate that neither a rise nor fall of seawater oxidation state led to the demise of the Ediacara biota. Lacking evidence for a redox driver, we hypothesize that sea-level regression and the widespread development of evaporative conditions in shallow-water environments negatively impacted the largely immobile, diffusion-dependent, and potentially stenothermal Ediacara biota by subaerial exposure, dehydration through osmosis, and/or large temperature variations in shallow water. Thereafter, normal salinity and subtle rises in shallow ocean O₂ levels in concert with tectonic and ecological factors could have driven the Cambrian radiation in oceans that remained O₂-depleted well into the Paleozoic Era.</p>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"24 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gbi.70066","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149048560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coralline Algal Beds as Carbonate Factories: From Local Production to Global Significance","authors":"Nadine Schubert,&nbsp;Tainá L. Gaspar,&nbsp;Marcial Cosme de Esteban,&nbsp;Celeste A. Diaz-Licona,&nbsp;Pedro Neves,&nbsp;Francisco Otero-Ferrer,&nbsp;Cláudia Ribeiro,&nbsp;Lidiane P. Gouvȇa,&nbsp;Viviana Peña,&nbsp;Fernando Tuya,&nbsp;João Silva","doi":"10.1111/gbi.70068","DOIUrl":"10.1111/gbi.70068","url":null,"abstract":"<div>\u0000 \u0000 <p>Biogenic marine carbonate production is a key component of the global carbon cycle, with shelf environments contributing disproportionately to global CaCO₃ production. Yet, empirical data remain scarce for many shelf habitats, including globally widespread coralline algal beds (CABs; rhodolith and maerl beds), formed by free-living coralline algae (rhodoliths <i>sensu lato</i>). Moreover, available CAB-associated carbonate production estimates remain poorly integrated across spatial scales, limiting assessments of their broader relevance. Here, we quantified rhodolith growth, through alizarin staining, and carbonate production of three northeastern Atlantic CABs and incorporated those estimates into a global dataset. We then scaled compiled rates by known CAB area to assess total carbonate production rates across spatial scales and compared CABs with other major carbonate producers. Rhodolith growth and carbonate production rates in the study region fell within the range reported for other temperate CABs, while CAB production rates globally varied widely across climatic zones (0.04–2.1 kg CaCO₃ m⁻² year⁻¹). When scaled to individual CAB areal extents, total carbonate production ranged from 5 t to 0.025 Gt year⁻¹. At larger spatial scales, available ecoregion-level estimates, representing ~70% of estimated global CAB area, yielded a total of 0.31–1.85 Gt CaCO₃ year⁻¹. Although area-based CAB production rates were generally lower than those of coral reefs, their broader distribution resulted in total carbonate production estimates that overlap with those for shallow tropical coral reefs and exceed those for calcareous green algae. Altogether, spatial scaling highlights CABs as local and regional carbonate-production hotspots that may contribute substantially (7%–44%) to global shelf carbonate production. However, while these estimates provide a first larger-scale approximation of CAB-associated carbonate production, it should be considered that they represent gross production and should therefore not be interpreted as net carbonate budgets. Better constraining the contribution of CABs to global carbonate cycling will require quantifying carbonate losses and accumulation, together with expanding the spatial coverage of production data.</p>\u0000 </div>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"24 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ministromatolite Modular Reef Framework, ~1.5 Ga, Yesanpo, North China","authors":"Dongjie Tang,&nbsp;Xiaoying Shi,&nbsp;Longfei Sun,&nbsp;Robert Riding","doi":"10.1111/gbi.70065","DOIUrl":"10.1111/gbi.70065","url":null,"abstract":"<div>\u0000 \u0000 <p>Earth's earliest known framework reef, ~1500-million-year-old Yesanpo Mound in the Wumishan Formation, North China, consists of columns and cones built by innumerable conjoined originally aragonitic ministromatolites, each ≤ 2 cm wide. The Mound contains numerous irregular, decimetric, cavities. These are now filled with carbonate mud, giant ooids, and originally aragonitic marine cement. The role of ministromatolites in constructing this modular framework very broadly resembles that of polyps in present-day scleractinian coral colonies. Yesanpo Mound preserves geochemical signatures and traces of organic filaments consistent with suboxic conditions, yet it predates the earliest reported reef-dwelling animals by ~600 Myr. Similar spaces in reef framework may have provided ideal habitats for cryptic biota during the late Proterozoic. These are prime targets in the continued search for early animal life.</p>\u0000 </div>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"24 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148962840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptation of Microbialite-Associated Prokaryotic Communities to Natural and Experimental Anoxic Conditions","authors":"Jeanne Caumartin,&nbsp;Karim Benzerara,&nbsp;Ana Gutiérrez-Preciado,&nbsp;Miguel Iniesto,&nbsp;Paola Bertolino,&nbsp;Maria Ciobanu,&nbsp;Christophe Thomazo,&nbsp;Robin Havas,&nbsp;Didier Jézéquel,&nbsp;Philippe Deschamps,&nbsp;Rosaluz Tavera,&nbsp;David Moreira,&nbsp;Purificaciόn Lόpez-Garcίa","doi":"10.1111/gbi.70064","DOIUrl":"10.1111/gbi.70064","url":null,"abstract":"<p>Microbialites are rocks formed by microbial communities that influence, promote, and/or control the precipitation of mineral phases. The oldest microbialites date back to the Archean and formed under globally anoxic conditions. Accordingly, modern microbialites developing under oxic conditions are limited analogs of their earliest predecessors. We discovered microbialites in the deep, seasonally anoxic water column of crater lakes Alchichica and Atexcac (Mexico). We studied the prokaryotic communities of plankton and microbialites from oxic and anoxic layers, alongside the temporal dynamics of microbialite communities incubated under strict continuous anoxia. 16S rRNA gene amplicon sequencing showed shifts in the relative abundance of taxa under anoxia, rather than changes in overall diversity. Regardless of their original depth, microbialite-associated communities from oxic and anoxic zones converged after ~25 weeks of laboratory exposure to a N₂-H₂-CO₂ (85:10:5) atmosphere. Sequences assigned to likely anoxygenic photosynthetic taxa, notably within the Alpha- and Gammaproteobacteria, together with phyla associated with sulfate-reduction and other sulfur-cycling bacteria, increased in relative abundance. We isolated seven bacterial strains under anoxia, some of them biomineralizing. Several of these strains were cyanobacteria affiliated with the Leptolyngbyales, suggesting that they either continue to perform oxygenic photosynthesis or, hypothetically, switch to H₂S-dependent anoxygenic photosynthesis. Our results indicate that these microbialite communities adapt to long-term anoxia (more than 70 weeks) under laboratory conditions, likely sustaining photosynthetic alkalinization and carbonate precipitation under such conditions.</p>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"24 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gbi.70064","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148928573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origins of Improved Hardness in Bioinspired Aragonite Precipitated Under Simulated Biologic Conditions","authors":"Boontharee Chomhom,&nbsp;Gabriela A. Farfan,&nbsp;Samantha Greeves,&nbsp;Kirsty Penkman,&nbsp;Adrian A. Finch,&nbsp;Susan Fitzer,&nbsp;Roland Kröger,&nbsp;Alex Brasier,&nbsp;John Still,&nbsp;Matthieu Clog,&nbsp;Nicola Allison","doi":"10.1111/gbi.70060","DOIUrl":"10.1111/gbi.70060","url":null,"abstract":"<p>Biogenic aragonite is a composite of mineral and biomolecules that exhibits superior material properties compared to its inorganic analog. This superiority underpins the success of the bioaragonite structures which support coral reefs and shell fisheries, yet the mechanisms improving the physical resilience of bioaragonite are not well understood. In this study, aragonite is synthesised under chemical conditions which simulate those of calcification sites in marine organisms. Aspartic acid, glutamic acid, and glycine in solution are incorporated into the aragonite at concentrations typically observed in marine biominerals and are observed to significantly improve aragonite Vickers hardness. Aspartic acid is incorporated more efficiently than glutamic acid or glycine, but for comparable amounts of amino acid incorporation, glycine improves aragonite hardness significantly more than either aspartic or glutamic acid. Glycine and glutamic acid incorporation reduce the aragonite grain size, thereby improving resilience to indentation via energy dissipation along grain boundaries. In contrast, aspartic acid also improves hardness on a smaller scale, possibly due to crystal structure distortions. These results suggest that amino acid incorporation influences biogenic aragonite hardness via multiple mechanisms and provide a prototype for exploring the influence of more complicated biomineral proteins.</p>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"24 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gbi.70060","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148917752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biosignature Preservation in Stromatolites From the Carri Laufquen Lakes System, Patagonia: Implications for Martian Palaeolacustrine Environments","authors":"Victor Amir Cardoso Dorneles,&nbsp;Maëva Millan,&nbsp;Fernando J. Gómez,&nbsp;Primož Šket,&nbsp;Jens Najorka,&nbsp;Cindy Broderick,&nbsp;Wren Montgomery,&nbsp;Barbara Cavalazzi,&nbsp;Keyron Hickman-Lewis","doi":"10.1111/gbi.70063","DOIUrl":"10.1111/gbi.70063","url":null,"abstract":"<p>The Carri Laufquen Lakes System is a highly alkaline, basalt-hosted lacustrine environment in northern Patagonia, Argentina. Diverse morphologies of Late Pleistocene sub-fossil stromatolites occur along the lakeshores. Using detailed optical and electron microscopy, spectroscopy and organic geochemical analyses, this study shows that stromatolite growth and early diagenetic processes were strongly influenced by microbially controlled organomineralisation. Mineralisation of extracellular polymeric substances and cyanobacterial sheaths promoted early lithification and exceptional preservation of stromatolite fabrics and biosignatures. Organic matter is closely associated with Al–bearing silicate minerals at the micro–nanoscale, enhancing fossilisation potential and preserving biogeochemical signatures. The resulting mineral assemblage in the Carri Laufquen stromatolites, dominated by Mg-carbonate with minor Al-silicates and carbonaceous material, resembles the geochemistry of ancient lacustrine deposits around the margins of Jezero crater, highlighting the propensity of such deposits for biosignature preservation, and providing a framework for detailed characterisation of such materials following Mars Sample Return.</p>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"24 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gbi.70063","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148910145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Red to Green: A Lipid Biomarker Record of Tonian-Ediacaran Algae in Siberia","authors":"Adriana I. Rizzo,&nbsp;Andrey Bekker,&nbsp;Anton B. Kuznetsov,&nbsp;Victoria B. Ershova,&nbsp;Yijun Xiong,&nbsp;Karl E. Karlstrom,&nbsp;Simon W. Poulton,&nbsp;Gordon D. Love","doi":"10.1111/gbi.70061","DOIUrl":"10.1111/gbi.70061","url":null,"abstract":"<p>Multiple lines of evidence point to a major diversification of Eukarya in the late Tonian period, ca. 800–720 Ma ago. Regular steranes, lipid biomarkers primarily sourced from eukaryotes, are first unambiguously reported from multiple sites. Here, we present lipid biomarker stratigraphic records from two drill-cores from the Lena-Anabar Basin in northern Siberia, in addition to new biomarker data from the Walcott Member of the Chuar Group, USA. The Siberian drill-cores span the late Tonian (ca. 800–750 Ma) and late Ediacaran-early Cambrian periods (ca. 565–539 Ma), with Cryogenian strata absent. Compositional differences in sedimentary organic matter were assessed using a suite of biomarker hydrocarbon parameters, with seawater redox and phosphorus availability determined using iron speciation, trace metals, and phosphorus phase partitioning. Steranes were consistently detected in Tonian strata in the Siberian drill-cores, with sterane/hopane (S/H) values being uniformly low (&lt; 0.05), consistent with a low-productivity, marine environment in which bacteria outcompeted eukaryotes for limited nutrients. This was confirmed by phosphorus phase partitioning data that suggest that phosphorus was a key limiter of late Tonian marine eukaryote abundance. Unlike Siberia, late Tonian samples from the Chuar Group showed consistently higher S/H values (up to 0.38) and elevated total organic carbon content (1.3–5.6 wt.%) indicative of higher algal productivity in a eutrophic marine setting. Tonian strata primarily yielded cholestane (C₂₇ sterane), indicating red algal dominance with small contributions of cryostane and ergostane (C₂₈ steranes), while Ediacaran strata in both Siberian drill-cores were dominated by stigmastane (C₂₉ sterane), indicating green algal dominance, capturing this global secular shift in a single location. The distinctive C₂₇-sterane dominance commonly found for the late Tonian is captured here for the first time from an oligotrophic marine environment that sustained oxic to weakly reducing redox conditions, supporting the idea that the Tonian rise of algae occurred widely across the oceans.</p>","PeriodicalId":173,"journal":{"name":"Geobiology","volume":"24 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13547773/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148899850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}