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Leapaldt HC, Frantz CM, Olsen-Valdez J, Snell KE, Trower EJ, Ingalls M. Primary to post-depositional microbial controls on the stable and clumped isotope record of shoreline sediments at Fayetteville Green Lake. GEOBIOLOGY 2024; 22:e12609. [PMID: 38958391 DOI: 10.1111/gbi.12609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 04/22/2024] [Accepted: 06/11/2024] [Indexed: 07/04/2024]
Abstract
Lacustrine carbonates are a powerful archive of paleoenvironmental information but are susceptible to post-depositional alteration. Microbial metabolisms can drive such alteration by changing carbonate saturation in situ, thereby driving dissolution or precipitation. The net impact these microbial processes have on the primary δ18O, δ13C, and Δ47 values of lacustrine carbonate is not fully known. We studied the evolution of microbial community structure and the porewater and sediment geochemistry in the upper ~30 cm of sediment from two shoreline sites at Green Lake, Fayetteville, NY over 2 years of seasonal sampling. We linked seasonal and depth-based changes of porewater carbonate chemistry to microbial community composition, in situ carbon cycling (using δ13C values of carbonate, dissolved inorganic carbon (DIC), and organic matter), and dominant allochems and facies. We interpret that microbial processes are a dominant control on carbon cycling within the sediment, affecting porewater DIC, aqueous carbon chemistry, and carbonate carbon and clumped isotope geochemistry. Across all seasons and sites, microbial organic matter remineralization lowers the δ13C of the porewater DIC. Elevated carbonate saturation states in the sediment porewaters (Ω > 3) were attributed to microbes from groups capable of sulfate reduction, which were abundant in the sediment below 5 cm depth. The nearshore carbonate sediments at Green Lake are mainly composed of microbialite intraclasts/oncoids, charophytes, larger calcite crystals, and authigenic micrite-each with a different origin. Authigenic micrite is interpreted to have precipitated in situ from the supersaturated porewaters from microbial metabolism. The stable carbon isotope values (δ13Ccarb) and clumped isotope values (Δ47) of bulk carbonate sediments from the same depth horizons and site varied depending on both the sampling season and the specific location within a site, indicating localized (μm to mm) controls on carbon and clumped isotope values. Our results suggest that biological processes are a dominant control on carbon chemistry within the sedimentary subsurface of the shorelines of Green Lake, from actively forming microbialites to pore space organic matter remineralization and micrite authigenesis. A combination of biological activity, hydrologic balance, and allochem composition of the sediments set the stable carbon, oxygen, and clumped isotope signals preserved by the Green Lake carbonate sediments.
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Affiliation(s)
- Hanna C Leapaldt
- Department of Geosciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Carie M Frantz
- Department of Earth and Environmental Sciences, Weber State University, Ogden, Utah, USA
| | - Juliana Olsen-Valdez
- Department of Geological Sciences, University of Colorado, Boulder, Colorado, USA
| | - Kathryn E Snell
- Department of Geological Sciences, University of Colorado, Boulder, Colorado, USA
| | - Elizabeth J Trower
- Department of Geological Sciences, University of Colorado, Boulder, Colorado, USA
| | - Miquela Ingalls
- Department of Geosciences, The Pennsylvania State University, University Park, Pennsylvania, USA
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Jung J, Loschko T, Reich S, Rassoul-Agha M, Werner MS. Newly identified nematodes from the Great Salt Lake are associated with microbialites and specially adapted to hypersaline conditions. Proc Biol Sci 2024; 291:20232653. [PMID: 38471558 PMCID: PMC10932707 DOI: 10.1098/rspb.2023.2653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 02/09/2024] [Indexed: 03/14/2024] Open
Abstract
Extreme environments enable the study of simplified food-webs and serve as models for evolutionary bottlenecks and early Earth ecology. We investigated the biodiversity of invertebrate meiofauna in the benthic zone of the Great Salt Lake (GSL), Utah, USA, one of the most hypersaline lake systems in the world. The hypersaline bays within the GSL are currently thought to support only two multicellular animals: brine fly larvae and brine shrimp. Here, we report the presence, habitat, and microbial interactions of novel free-living nematodes. Nematode diversity drops dramatically along a salinity gradient from a freshwater river into the south arm of the lake. In Gilbert Bay, nematodes primarily inhabit reef-like organosedimentary structures built by bacteria called microbialites. These structures likely provide a protective barrier to UV and aridity, and bacterial associations within them may support life in hypersaline environments. Notably, sampling from Owens Lake, another terminal lake in the Great Basin that lacks microbialites, did not recover nematodes from similar salinities. Phylogenetic divergence suggests that GSL nematodes represent previously undescribed members of the family Monhysteridae-one of the dominant fauna of the abyssal zone and deep-sea hydrothermal vents. These findings update our understanding of halophile ecosystems and the habitable limit of animals.
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Affiliation(s)
- Julie Jung
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Tobias Loschko
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
- Max Planck Institute for Biology, Tübingen, Germany
| | - Shelley Reich
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Maxim Rassoul-Agha
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Michael S. Werner
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
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Lomakina AV, Bukin SV, Pogodaeva TV, Turchyn AV, Khlystov OM, Khabuev AV, Ivanov VG, Krylov AA, Zemskaya TI. Microbial diversity and authigenic siderite mediation in sediments surrounding the Kedr-1 mud volcano, Lake Baikal. GEOBIOLOGY 2023; 21:770-790. [PMID: 37698260 DOI: 10.1111/gbi.12575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/07/2023] [Accepted: 08/29/2023] [Indexed: 09/13/2023]
Abstract
The gas hydrate-bearing structure-mud volcano Kedr-1 (Lake Baikal, southern basin)-is located near the coal-bearing sediments of the Tankhoy formation of Oligocene-Miocene age and can be an ideal source of gas-saturated fluid. A significant amount of siderite minerals (FeCO3 ) were collected from sediments at depths ranging from 0.5 to 327 cm below the lake floor (cmblf). An important feature of these carbonate minerals is the extremely strong enrichment in the heavy 13 C isotope, reaching values of +33.3‰ VPDB. The δ13 C of the siderite minerals, as well as their morphology and elemental composition, and the δ13 CDIC of the co-existing pore water, differed across layers of the core, which implies at least two generations of siderite formation. Here, we leverage mineralogical and geochemical data with 16S rRNA data from the microbial communities in sediments surrounding layers containing siderite minerals. Statistical data reveal the formation of three clusters of microbial communities based on taxonomical composition, key taxa among bacteria and archaea, and environmental parameters. Diversity and richness estimators decrease with sediment depth, with several similar prevailing clades located at the bottom of the core. Most of the taxa in the deep sediments could be associated with putative metabolisms involving organotrophic fermentation (Bathyarchaeia, Caldatribacteriota, and Chloroflexota). Various groups of methanogens (Methanoregulaceae, Methanosaetaceae, and Methanomassiliicoccales) and methanotrophic (Methanoperedenaceae) archaea are present in the sediment at variable relative abundances throughout the sampled depth. Based on the physicochemical characteristics of the sediment, carbon isotope analysis of carbonate minerals and DIC, and phylogenetic analysis of individual taxa and their metabolic potential, we present several models for subsurface siderite precipitation in Lake Baikal sediments.
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Affiliation(s)
| | | | | | | | | | | | | | - Aleksey A Krylov
- Limnological Institute, SB RAS, Irkutsk, Russia
- VNIIOkeangeologia, St. Petersburg, Russia
- Institute of Earth Science, St Petersburg State University, St. Petersburg, Russia
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Pan B, Liu S, Wang Y, Li D, Li M. FT-ICR-MS combined with fluorescent spectroscopy reveals the driving mechanism of the spatial variation in molecular composition of DOM in 22 plateau lakes. ENVIRONMENTAL RESEARCH 2023:116272. [PMID: 37276978 DOI: 10.1016/j.envres.2023.116272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 05/21/2023] [Accepted: 05/27/2023] [Indexed: 06/07/2023]
Abstract
Dissolved organic matter (DOM) is the largest carbon pool and directly affects the biogeochemistry in lakes. In the current study, fourier transform ion cyclotron mass spectrometry (FT-ICR-MS) combined with fluorescent spectroscopy was used to assess the molecular composition and driving mechanism of DOM in 22 plateau lakes in Mongolia Plateau Lakes Region (MLR), Qinghai Plateau Lakes Region (QLR) and Tibet Plateau Lakes Region (TLR) of China. The limnic dissolved organic carbon (DOC) content ranged from 3.93 to 280.8 mg L-1 and the values in MLR and TLR were significantly higher than that in QLR. The content of lignin was the highest in each lake and showed a gradually decreasing trend from MLR to TLR. Random forest model and structural equation model implied that altitude played an important role in lignin degradation while the contents of total nitrogen (TN) and chlorophyll a (Chl-a) have a great influence on the increase of DOM Shannon index. Our results also suggested that the inspissation of DOC and the promoted endogenous DOM production caused by the inspissation of nutrient resulted in a positive relationship between limnic DOC content and limnic factors such as salinity, alkalinity and nutrient concentration. From MLR to QLR and TLR, the molecular weight and the number of double bonds gradually decreased but the humification index (HIX) also decreased. In addition, from the MLR to the TLR, the proportion of lignin gradually decreased, while the proportion of lipid gradually increased. Both above results suggested that photodegradation was dominated in lakes of TLR, while microbial degradation was dominated in lakes of MLR.
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Affiliation(s)
- Baozhu Pan
- State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, Shaanxi, PR China
| | - Siwan Liu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, PR China
| | - Yeyong Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, PR China
| | - Dianbao Li
- State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, Shaanxi, PR China
| | - Ming Li
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, PR China.
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Chen M, Conroy JL, Geyman EC, Sanford RA, Chee‐Sanford JC, Connor LM. Stable carbon isotope values of syndepositional carbonate spherules and micrite record spatial and temporal changes in photosynthesis intensity. GEOBIOLOGY 2022; 20:667-689. [PMID: 35851522 PMCID: PMC9543828 DOI: 10.1111/gbi.12509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 05/27/2022] [Accepted: 06/26/2022] [Indexed: 06/15/2023]
Abstract
Marine and lacustrine carbonate minerals preserve carbon cycle information, and their stable carbon isotope values (δ13 C) are frequently used to infer and reconstruct paleoenvironmental changes. However, multiple processes can influence the δ13 C values of bulk carbonates, confounding the interpretation of these values in terms of conditions at the time of mineral precipitation. Co-existing carbonate forms may represent different environmental conditions, yet few studies have analyzed δ13 C values of syndepositional carbonate grains of varying morphologies to investigate their origins. Here, we combine stable isotope analyses, metagenomics, and geochemical modeling to interpret δ13 C values of syndepositional carbonate spherules (>500 μm) and fine-grained micrite (<63 μm) from a ~1600-year-long sediment record of a hypersaline lake located on the coral atoll of Kiritimati, Republic of Kiribati (1.9°N, 157.4°W). Petrographic, mineralogic, and stable isotope results suggest that both carbonate fractions precipitate in situ with minor diagenetic alterations. The δ13 C values of spherules are high compared to the syndepositional micrite and cannot be explained by mineral differences or external perturbations, suggesting a role for local biological processes. We use geochemical modeling to test the hypothesis that the spherules form in the surface microbial mat during peak diurnal photosynthesis when the δ13 C value of dissolved inorganic carbon is elevated. In contrast, we hypothesize that the micrite may precipitate more continuously in the water as well as in sub-surface, heterotrophic layers of the microbial mat. Both metagenome and geochemical model results support a critical role for photosynthesis in influencing carbonate δ13 C values. The down-core spherule-micrite offset in δ13 C values also aligns with total organic carbon values, suggesting that the difference in the δ13 C values of spherules and micrite may be a more robust, inorganic indicator of variability in productivity and local biological processes through time than the δ13 C values of individual carbonate forms.
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Affiliation(s)
- Mingfei Chen
- Department of GeologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
| | - Jessica L. Conroy
- Department of GeologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
- Department of Plant BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
| | - Emily C. Geyman
- Division of Geological and Planetary SciencesCalifornia Institute of TechnologyPasadenaCaliforniaUSA
| | - Robert A. Sanford
- Department of GeologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
| | - Joanne C. Chee‐Sanford
- Department of Natural Resource and Environmental ScienceUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
- USDA‐ARSUrbanaIllinoisUSA
| | - Lynn M. Connor
- Department of Natural Resource and Environmental ScienceUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
- USDA‐ARSUrbanaIllinoisUSA
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