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Falk D, Wings O, Unitt R, Wade J, McNamara ME. Fossilized anuran soft tissues reveal a new taphonomic model for the Eocene Geiseltal Konservat-Lagerstätte, Germany. Sci Rep 2024; 14:7876. [PMID: 38654038 DOI: 10.1038/s41598-024-55822-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 02/28/2024] [Indexed: 04/25/2024] Open
Abstract
The Eocene Geiseltal Konservat-Lagerstätte (Germany) is famous for reports of three dimensionally preserved soft tissues with sub-cellular detail. The proposed mode of preservation, direct replication in silica, is not known in other fossils and has not been verified using modern approaches. Here, we investigated the taphonomy of the Geiseltal anurans using diverse microbeam imaging and chemical analytical techniques. Our analyses confirm the preservation of soft tissues in all body regions but fail to yield evidence for silicified soft tissues. Instead, the anuran soft tissues are preserved as two layers that differ in microstructure and composition. Layer 1 comprises sulfur-rich carbonaceous microbodies interpreted as melanosomes. Layer 2 comprises the mid-dermal Eberth-Katschenko layer, preserved in calcium phosphate. In addition, patches of original aragonite crystals define the former position of the endolymphatic sac. The primary modes of soft tissue preservation are therefore sulfurization of melanosomes and phosphatization of more labile soft tissues, i.e., skin. This is consistent with the taphonomy of vertebrates in many other Konservat-Lagerstätten. These findings emphasize an emerging model for pervasive preservation of vertebrate soft tissues via melanosome films, particularly in stagnation-type deposits, with phosphatization of more labile tissues where tissue biochemistry is favorable.
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Affiliation(s)
- Daniel Falk
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, T23 TK30, Ireland.
- Environmental Research Institute, University College Cork, Lee Rd, Cork, T23 XE10, Ireland.
| | - Oliver Wings
- Natural History Museum Bamberg, Staatliche Naturwissenschaftliche Sammlungen Bayerns, Fleischstraße 2, 96047, Bamberg, Germany
| | - Richard Unitt
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, T23 TK30, Ireland
- Environmental Research Institute, University College Cork, Lee Rd, Cork, T23 XE10, Ireland
- Copper Coast UNESCO Global Geopark, Knockmahon, Bunmahon, X42 T923, Ireland
| | - Jon Wade
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK
| | - Maria E McNamara
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, T23 TK30, Ireland
- Environmental Research Institute, University College Cork, Lee Rd, Cork, T23 XE10, Ireland
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Dhami NK, Greenwood PF, Poropat SF, Tripp M, Elson A, Vijay H, Brosnan L, Holman AI, Campbell M, Hopper P, Smith L, Jian A, Grice K. Microbially mediated fossil concretions and their characterization by the latest methodologies: a review. Front Microbiol 2023; 14:1225411. [PMID: 37840715 PMCID: PMC10576451 DOI: 10.3389/fmicb.2023.1225411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/14/2023] [Indexed: 10/17/2023] Open
Abstract
The study of well-preserved organic matter (OM) within mineral concretions has provided key insights into depositional and environmental conditions in deep time. Concretions of varied compositions, including carbonate, phosphate, and iron-based minerals, have been found to host exceptionally preserved fossils. Organic geochemical characterization of concretion-encapsulated OM promises valuable new information of fossil preservation, paleoenvironments, and even direct taxonomic information to further illuminate the evolutionary dynamics of our planet and its biota. Full exploitation of this largely untapped geochemical archive, however, requires a sophisticated understanding of the prevalence, formation controls and OM sequestration properties of mineral concretions. Past research has led to the proposal of different models of concretion formation and OM preservation. Nevertheless, the formation mechanisms and controls on OM preservation in concretions remain poorly understood. Here we provide a detailed review of the main types of concretions and formation pathways with a focus on the role of microbes and their metabolic activities. In addition, we provide a comprehensive account of organic geochemical, and complimentary inorganic geochemical, morphological, microbial and paleontological, analytical methods, including recent advancements, relevant to the characterization of concretions and sequestered OM. The application and outcome of several early organic geochemical studies of concretion-impregnated OM are included to demonstrate how this underexploited geo-biological record can provide new insights into the Earth's evolutionary record. This paper also attempts to shed light on the current status of this research and major challenges that lie ahead in the further application of geo-paleo-microbial and organic geochemical research of concretions and their host fossils. Recent efforts to bridge the knowledge and communication gaps in this multidisciplinary research area are also discussed, with particular emphasis on research with significance for interpreting the molecular record in extraordinarily preserved fossils.
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Affiliation(s)
- Navdeep K. Dhami
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Paul F. Greenwood
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Stephen F. Poropat
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Madison Tripp
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Amy Elson
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Hridya Vijay
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Luke Brosnan
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Alex I. Holman
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Matthew Campbell
- The Trace and Environmental DNA lab (trEND), School of Molecular and Life Sciences, Curtin University, Perth, WA, Australia
| | - Peter Hopper
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Lisa Smith
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Andrew Jian
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
| | - Kliti Grice
- Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth, WA, Australia
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Drumheller SK, Boyd CA, Barnes BMS, Householder ML. Biostratinomic alterations of an Edmontosaurus "mummy" reveal a pathway for soft tissue preservation without invoking "exceptional conditions". PLoS One 2022; 17:e0275240. [PMID: 36223345 PMCID: PMC9555629 DOI: 10.1371/journal.pone.0275240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 09/12/2022] [Indexed: 11/05/2022] Open
Abstract
Removal or protection from biostratinomic agents of decomposition, such as predators and scavengers, is widely seen as a requirement for high-quality preservation of soft tissues in the fossil record. In this context, extremely rapid burial is an oft-cited mechanism for shielding remains from degradation, but not all fossils fit nicely into this paradigm. Dinosaurian mummies in particular seemingly require two mutually exclusive taphonomic processes to preserve under that framework: desiccation and rapid burial. Here we present a recently prepared Edmontosaurus mummy that reveals an alternate fossilization pathway for resistant soft tissues (e.g., skin and nails). While the skin on this specimen is well-preserved in three dimensions and contains biomarkers, it is deflated and marked by the first documented examples of injuries consistent with carnivore activity on dinosaurian soft tissue during the perimortem interval. Incomplete scavenging of the carcass provided a route for the gases, fluids, and microbes associated with decomposition to escape, allowing more durable soft tissues to persist through the weeks to months required for desiccation prior to entombment and fossilization. This pathway is consistent with actualistic observations and explains why dinosaurian skin, while rare, is more commonly preserved than expected if extreme circumstances were required for its preservation. More broadly, our assumptions guide specimen collection and research, and the presence of soft tissues and biomolecules in fossils that demonstrably were not rapidly buried, such as this mummy, suggests that such types of evidence may be substantially more common than previously assumed.
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Affiliation(s)
- Stephanie K. Drumheller
- Department of Earth and Planetary Sciences, University of Tennessee–Knoxville, Knoxville, Tennessee, United States of America
- * E-mail: (SKD); (CAB)
| | - Clint A. Boyd
- Fossil Resource Management Program, North Dakota Geological Survey, Bismarck, North Dakota, United States of America
- * E-mail: (SKD); (CAB)
| | - Becky M. S. Barnes
- Fossil Resource Management Program, North Dakota Geological Survey, Bismarck, North Dakota, United States of America
| | - Mindy L. Householder
- State Historical Society of North Dakota, Bismarck, North Dakota, United States of America
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4
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Mähler B, Janssen K, Tahoun M, Tomaschek F, Schellhorn R, Müller CE, Bierbaum G, Rust J. Adipocere formation in biofilms as a first step in soft tissue preservation. Sci Rep 2022; 12:10122. [PMID: 35710834 PMCID: PMC9203803 DOI: 10.1038/s41598-022-14119-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 06/01/2022] [Indexed: 12/03/2022] Open
Abstract
The preservation of soft tissue in the fossil record is mostly due to the replacement of organic structures by minerals (e.g. calcite, aragonite or apatite) called pseudomorphs. In rare cases soft tissues were preserved by pyrite. We assume that adipocere, as the shaping component, might be a preliminary stage in the pyritisation of soft tissues under anaerobic conditions. Using high-performance liquid chromatography coupled to ultraviolet and mass spectrometric detection (HPLC–UV/MS) and confocal Raman spectroscopy (CRS) we were able to demonstrate the transformation of the hepatopancreas (digestive gland) of the crayfish Cambarellus diminutus [Hobbs 1945] into adipocere within only 9 days, just inside a biofilm. Microorganisms (bacteria and fungi) which were responsible for the biofilm (Sphaerotilus [Kutzig 1833] and Pluteus [Fries 1857]) and maybe the adipocere formation (Clostridium [Prazmowski 1880]) were detected by 16S rRNA gene amplicon sequencing. Furthermore, micro-computed tomography (µ-CT) analyses revealed a precipitation of calcite and further showed that in animals with biofilm formation calcite precipitates in finer grained crystals than in individuals without biofilm formation, and that the precipitates were denser and replicated the structures of the cuticles better than the coarse precipitates.
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Affiliation(s)
- Bastian Mähler
- Section Palaeontology, Institute of Geosciences, Rheinische Friedrich-Wilhelms Universität Bonn, 53115, Bonn, Germany.
| | - Kathrin Janssen
- Institute of Medical Microbiology, Immunology and Parasitology, Medical Faculty, Rheinische Friedrich-Wilhelms Universität, 53127, Bonn, Germany
| | - Mariam Tahoun
- Pharmazeutisches Institut, Pharmazeutische und Medizinische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53121, Bonn, Germany
| | - Frank Tomaschek
- Section Geochemistry/Petrology, Institute of Geosciences, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115, Bonn, Germany
| | - Rico Schellhorn
- Section Palaeontology, Institute of Geosciences, Rheinische Friedrich-Wilhelms Universität Bonn, 53115, Bonn, Germany
| | - Christa E Müller
- Pharmazeutisches Institut, Pharmazeutische und Medizinische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53121, Bonn, Germany
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology, Medical Faculty, Rheinische Friedrich-Wilhelms Universität, 53127, Bonn, Germany
| | - Jes Rust
- Section Palaeontology, Institute of Geosciences, Rheinische Friedrich-Wilhelms Universität Bonn, 53115, Bonn, Germany
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5
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Mojarro A, Cui X, Zhang X, Jost AB, Bergmann KD, Vinther J, Summons RE. Comparative soft-tissue preservation in Holocene-age capelin concretions. GEOBIOLOGY 2022; 20:377-398. [PMID: 34747129 DOI: 10.1111/gbi.12480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 10/21/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
Determining how soft tissues are preserved and persist through geologic time are continuing challenge because decay begins immediately after senescence while diagenetic transformations generally progress over days to millions of years. However, in recent years, carbonate concretions containing partially-to-fully decayed macroorganisms have proven to be remarkable windows into the diagenetic continuum revealing insights into the fossilization process. This is because most concretions are the result of biologically induced mineral precipitation caused by the localized decay of organic matter, which oftentimes preserves a greater biological signal relative to their host sediment. Here we present a comparative lipid biomarker study investigating processes associated with soft-tissue preservation within Holocene-age carbonate concretions that have encapsulated modern capelin (Mallotus villosus). We focus on samples collected from two depositional settings that have produced highly contrasting preservation end-members: (1) Kangerlussuaq, Greenland: a marine environment, which, due to isostatic rebound, has exposed strata containing concretions exhibiting exceptional soft-tissue preservation (6-7 kya), and (2) Greens Creek, Ottawa, Canada: a paleo brackish-to-freshwater marine excursion containing concretions exhibiting skeletal remains (~11 kya). Lipid biomarker analysis reveals endogenous capelin tissues and productive waters at Kangerlussuaq that are in sharp contrast to Greens Creek concretions, which lack appreciable capelin and environmental signals. Comparable distributions of bacterial fatty acids and statistical analyses suggest soft-tissue preservation within concretions is agnostic to specific heterotrophic decay communities. We, therefore, interpret preservation within carbonate concretions may represent a race between microbially induced authigenic precipitation and decay. Namely, factors resulting in exceptional preservation within concretions likely include: (1) organic matter input, (2) rate of decay, (3) carbonate saturation, (4) porewater velocity, and (5) rate of authigenic (carbonate) precipitation resulting in arrested decay/bacterial respiration due to cementing pore spaces limiting the diffusion of electron acceptors into the decay foci.
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Affiliation(s)
- Angel Mojarro
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Xingqian Cui
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Xiaowen Zhang
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Adam B Jost
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Kristin D Bergmann
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Jakob Vinther
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Roger E Summons
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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6
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Janssen K, Mähler B, Rust J, Bierbaum G, McCoy VE. The complex role of microbial metabolic activity in fossilization. Biol Rev Camb Philos Soc 2021; 97:449-465. [PMID: 34649299 DOI: 10.1111/brv.12806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 12/22/2022]
Abstract
Bacteria play an important role in the fossilization of soft tissues; their metabolic activities drive the destruction of the tissues and also strongly influence mineralization. Some environmental conditions, such as anoxia, cold temperatures, and high salinity, are considered widely to promote fossilization by modulating bacterial activity. However, bacteria are extremely diverse, and have developed metabolic adaptations to a wide range of stressful conditions. Therefore, the influence of the environment on bacterial activity, and of their metabolic activity on fossilization, is complex. A number of examples illustrate that simple, general assumptions about the role of bacteria in soft tissue fossilization cannot explain all preservational pathways: (i) experimental results show that soft tissues of cnidaria decay less in oxic than anoxic conditions, and in the fossil record are found more commonly in fossil sites deposited under oxic conditions rather than anoxic environments; (ii) siderite concretions, which often entomb soft tissue fossils, precipitate due to a complex mixture of sulfate- and iron reduction by some bacterial species, running counter to original theories that iron reduction is the primary driver of siderite concretion growth; (iii) arthropod brains, now widely accepted to be preserved in many Cambrian fossil sites, are one of the first structures to decay in taphonomic experiments, indicating that their fossilization processes are complex and influenced by bacterial activity. In order to expand our understanding of the complex process of bacterially driven soft tissue fossilization, more research needs to be done, on fossils themselves and in taphonomic experiments, to determine how the complex variation in microbial metabolic activity influences decay and mineralization.
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Affiliation(s)
- Kathrin Janssen
- Institute of Medical Microbiology, Immunology and Parasitology, Medical Faculty, Rheinische Friedrich-Wilhelms Universität, 53127, Bonn, Germany
| | - Bastian Mähler
- Paleontology Section, Institute of Geosciences, Rheinische Friedrich-Wilhelms Universität Bonn, 53115, Bonn, Germany
| | - Jes Rust
- Paleontology Section, Institute of Geosciences, Rheinische Friedrich-Wilhelms Universität Bonn, 53115, Bonn, Germany
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology, Medical Faculty, Rheinische Friedrich-Wilhelms Universität, 53127, Bonn, Germany
| | - Victoria E McCoy
- Department of Geosciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, 53211, U.S.A
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7
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Janssen K, Low SL, Wang Y, Mu Q, Bierbaum G, Gee CT. Elucidating biofilm diversity on water lily leaves through 16S rRNA amplicon analysis: Comparison of four DNA extraction kits. APPLICATIONS IN PLANT SCIENCES 2021; 9:e11444. [PMID: 34504737 PMCID: PMC8419396 DOI: 10.1002/aps3.11444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
PREMISE Within a broader study on leaf fossilization in freshwater environments, a long-term study on the development and microbiome composition of biofilms on the foliage of aquatic plants has been initiated to understand how microbes and biofilms contribute to leaf decay and preservation. Here, water lily leaves are employed as a study model to investigate the relationship between bacterial microbiomes, biodegradation, and fossilization. We compare four DNA extraction kits to reduce biases in interpretation and to identify the most suitable kit for the extraction of DNA from bacteria associated with biofilms on decaying water lily leaves for 16S rRNA amplicon analysis. METHODS We extracted surface-associated DNA from Nymphaea leaves in early stages of decay at two water depth levels using four commercially available kits to identify the most suitable protocol for bacterial extraction, applying a mock microbial community standard to enable a reliable comparison of the kits. RESULTS Kit 4, the FastDNA Spin Kit for Soil, resulted in high DNA concentrations with better quality and yielded the most accurate depiction of the mock community. Comparison of the leaves at two water depths showed no significant differences in community composition. DISCUSSION The success of Kit 4 may be attributed to its use of bead beating with a homogenizer, which was more efficient in the lysis of Gram-positive bacteria than the manual vortexing protocols used by the other kits. Our results show that microbial composition on leaves during early decay remains comparable and may change only in later stages of decomposition.
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Affiliation(s)
- Kathrin Janssen
- Institute of Medical Microbiology, Immunology and Parasitology, University Clinic of Bonn, Rheinische Friedrich‐Wilhelms‐University Bonn, Venusberg‐Campus 153127BonnGermany
| | - Shook Ling Low
- Institute of Geosciences, Division of PaleontologyRheinische Friedrich‐Wilhelms‐University Bonn, Nussallee 853115BonnGermany
| | - Yan Wang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of SciencesMengla666303China
| | - Qi‐Yong Mu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of SciencesMengla666303China
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology, University Clinic of Bonn, Rheinische Friedrich‐Wilhelms‐University Bonn, Venusberg‐Campus 153127BonnGermany
| | - Carole T. Gee
- Institute of Geosciences, Division of PaleontologyRheinische Friedrich‐Wilhelms‐University Bonn, Nussallee 853115BonnGermany
- Huntington Botanical Gardens1151 Oxford Road, San MarinoCalifornia91108USA
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Jódar J, Rubio FM, Custodio E, Martos-Rosillo S, Pey J, Herrera C, Turu V, Pérez-Bielsa C, Ibarra P, Lambán LJ. Hydrogeochemical, isotopic and geophysical characterization of saline lake systems in semiarid regions: The Salada de Chiprana Lake, Northeastern Spain. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 728:138848. [PMID: 32570324 DOI: 10.1016/j.scitotenv.2020.138848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/18/2020] [Accepted: 04/18/2020] [Indexed: 06/11/2023]
Abstract
Most of the athalassic saline and hypersaline lakes are located in arid and semiarid regions where water availability drives the hydrological dynamics of the lake itself and the associated ecosystems. This is the case of the Salada de Chiprana Lake, in the Ebro River basin (Spain). It is the only athalassic permanent hypersaline lake in Western Europe, and where rare and endangered bacterial mats exist. This work presents a robust hydrogeological conceptual model for the lake system. The model evaluates the contribution of groundwater discharge to the whole water budget and explains the hydrological behaviour of the lake system. The lake behaves as a flow-through system rather than a closed basin. About 40% of total water outflow from the lake occurs as groundwater, whereas evaporation accounts for the remaining 60%. The surface water inflows are variable, but the groundwater contribution seems almost constant, amounting to 13% of the average total water inflow and contributing 1.9% of salt income. The high water salinity of the lake is controlled by evaporation, by saline water inflows from irrigation return flows, and the by groundwater outflows. The role of groundwater should be taken into account when drafting the water and land planning, once the conditions for the conservation of the algal mats are defined. A major contribution of this study is the water balance in the Salada de Chiprana Lake, which is consistent with a robust hydrogeological conceptual model defined upon scarce hydrogeological, hydrochemical and isotopic data in the local context as conditioned by the regional behaviour. The water balance is a key tool to help to correctly manage this unique athalassic saline lake, and the approach used here can be extrapolated to other similar ecosystems around the world.
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Affiliation(s)
- J Jódar
- Geological and Mining Institute of Spain (IGME), Spain.
| | - F M Rubio
- Geological and Mining Institute of Spain (IGME), Spain
| | - E Custodio
- Groundwater Hydrology Group, Department of Civil and Environmental Engineering, Technical University of Catalonia (UPC) & Royal Academy of Sciences of Spain, Spain
| | | | - J Pey
- ARAID, Instituto Pirenaico de Ecología (IPE-CSIC), Spain
| | - C Herrera
- Universidad Bernardo O'Higgins, Centro de Investigación y Desarrollo de Ecosistemas Hídricos, Santiago, Chile
| | - V Turu
- Marcel Chevalier Earth Science Foundation, Andorra
| | | | - P Ibarra
- Geological and Mining Institute of Spain (IGME), Spain
| | - L J Lambán
- Geological and Mining Institute of Spain (IGME), Spain
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9
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Bonde JW, Druschke PA, Hilton RP, Henrici AC, Rowland SM. Preservation of latest Cretaceous (Maastrichtian)-Paleocene frogs ( Eorubeta nevadensis) of the Sheep Pass Formation of east-central Nevada and implications for paleogeography of the Nevadaplano. PeerJ 2020; 8:e9455. [PMID: 32704447 PMCID: PMC7341540 DOI: 10.7717/peerj.9455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 06/09/2020] [Indexed: 11/20/2022] Open
Abstract
Here we report on exceptional preservation of remains of the frog Eorubeta nevadensis in deposits of the Sheep Pass Formation, ranging from Late Cretaceous to Eocene, in the south Egan Range, Nevada. This formation represents a lacustrine basin within the Sevier retroarc hinterland. The formation is subdivided into six members (A-F); of interest here are members B and C. The base of member B is ?uppermost Cretaceous-Paleocene, while member C is Paleocene. Member B frogs are preserved in three taphonomic modes. Mode 1 frogs are nearly complete and accumulated under attritional processes, with frogs settling on microbial mats, as evidenced by crenulated fabric of entombing limestone. Mode 2 involves accumulation of frogs as a result of attritional processes. These frogs are mostly complete with some showing evidence of invertebrate scavenging. Possible scavengers are gastropods, ostracods, and decapods. Mode 3 is represented by isolated, reworked remains of frogs as a result of storm activity, supported by the association of elements with disarticulated bivalves and mud rip-up clasts. Member C preserves frogs in two taphonomic modes. Mode 4 are nearly complete frogs that accumulated during discrete mass mortality events. Numerous individuals are preserved along bedding planes in identical preservational states. Mode 5 is beds of frog bone hash, which represent increased energy to the depositional system (likely tempestites) and reworking of previously buried frog remains. Taphonomy of the frogs, along with the associated fauna and flora, are consistent with preservation in a cool, temperate lake basin, supporting previous interpretations that the Nevadaplano was an elevated plateau during the late Cretaceous through the Eocene. This is a period of time coincident with a climatic thermal optimum, thus the most parsimonious explanation for a temperate lake at the latitude of east-central Nevada is to invoke high elevation, which is consistent with independent structural and clumped stable isotope studies.
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Affiliation(s)
- Joshua W Bonde
- Department of Conservation and Research, Las Vegas Natural History Museum, Las Vegas, NV, United States of America
| | - Peter A Druschke
- ExxonMobil Upstream Oil and Gas, Houston, TX, United States of America
| | - Richard P Hilton
- Natural History Museum, Sierra College, Rocklin, CA, United States of America
| | - Amy C Henrici
- Section of Vertebrate Paleontology, Carnegie Museum of Natural History, Pittsburgh, PA, United States of America
| | - Stephen M Rowland
- Department of Geoscience, University of Nevada-Las Vegas, Las Vegas, NV, United States of America
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10
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Gäb F, Ballhaus C, Stinnesbeck E, Kral AG, Janssen K, Bierbaum G. Experimental taphonomy of fish - role of elevated pressure, salinity and pH. Sci Rep 2020; 10:7839. [PMID: 32398712 PMCID: PMC7217852 DOI: 10.1038/s41598-020-64651-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/20/2020] [Indexed: 11/23/2022] Open
Abstract
Experiments are reported to reconstruct the taphonomic pathways of fish toward fossilisation. Acrylic glass autoclaves were designed that allow experiments to be carried out at elevated pressure up to 11 bar, corresponding to water depths of 110 m. Parameters controlled or monitored during decay reactions are pressure, salinity, proton activities (pH), electrochemical potentials (Eh), and bacterial populations. The most effective environmental parameters to delay or prevent putrefaction before a fish carcass is embedded in sediment are (1) a hydrostatic pressure in the water column high enough that a fish carcass may sink to the bottom sediment, (2) hypersaline conditions well above seawater salinity, and (3) a high pH to suppress the reproduction rate of bacteria. Anoxia, commonly assumed to be the key parameter for excellent preservation, is important in keeping the bottom sediment clear of scavengers but it does not seem to slow down or prevent putrefaction. We apply our results to the world-famous Konservat-Lagerstätten Eichstätt-Solnhofen, Green River, and Messel where fish are prominent fossils, and reconstruct from the sedimentary records the environmental conditions that may have promoted preservation. For Eichstätt-Solnhofen an essential factor may have been hypersaline conditions. Waters of the Green River lakes were at times highly alkaline and hypersaline because the lake stratigraphy includes horizons rich in sodium carbonate and halite. In the Messel lake sediments some fossiliferous horizons are rich in FeCO3 siderite, a mineral indicating highly reduced conditions and a high pH.
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Affiliation(s)
- Fabian Gäb
- Institut für Geowissenschaften, University of Bonn, 53115, Bonn, Germany.
| | - Chris Ballhaus
- Institut für Geowissenschaften, University of Bonn, 53115, Bonn, Germany.
| | - Eva Stinnesbeck
- Institut für Geowissenschaften, University of Bonn, 53115, Bonn, Germany
| | - Anna Gabriele Kral
- Institut für Geowissenschaften, University of Bonn, 53115, Bonn, Germany
| | - Kathrin Janssen
- Institut für Medizinische Mikrobiologie, Immunologie und Parasitologie, University Hospital Bonn, 53127, Bonn, Germany
| | - Gabriele Bierbaum
- Institut für Medizinische Mikrobiologie, Immunologie und Parasitologie, University Hospital Bonn, 53127, Bonn, Germany
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Pinheiro FL, Prado G, Ito S, Simon JD, Wakamatsu K, Anelli LE, Andrade JAF, Glass K. Chemical characterization of pterosaur melanin challenges color inferences in extinct animals. Sci Rep 2019; 9:15947. [PMID: 31685890 PMCID: PMC6828676 DOI: 10.1038/s41598-019-52318-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 10/11/2019] [Indexed: 12/18/2022] Open
Abstract
Melanosomes (melanin-bearing organelles) are common in the fossil record occurring as dense packs of globular microbodies. The organic component comprising the melanosome, melanin, is often preserved in fossils, allowing identification of the chemical nature of the constituent pigment. In present-day vertebrates, melanosome morphology correlates with their pigment content in selected melanin-containing structures, and this interdependency is employed in the color reconstruction of extinct animals. The lack of analyses integrating the morphology of fossil melanosomes with the chemical identification of pigments, however, makes these inferences tentative. Here, we chemically characterize the melanin content of the soft tissue headcrest of the pterosaur Tupandactylus imperator by alkaline hydrogen peroxide oxidation followed by high-performance liquid chromatography. Our results demonstrate the unequivocal presence of eumelanin in T. imperator headcrest. Scanning electron microscopy followed by statistical analyses, however, reveal that preserved melanosomes containing eumelanin are undistinguishable to pheomelanin-bearing organelles of extant vertebrates. Based on these new findings, straightforward color inferences based on melanosome morphology may not be valid for all fossil vertebrates, and color reconstructions based on ultrastructure alone should be regarded with caution.
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Affiliation(s)
- Felipe L Pinheiro
- Laboratório de Paleobiologia, Universidade Federal do Pampa, São Gabriel, 97300-162, Brazil.
| | - Gustavo Prado
- Instituto de Geociências, Universidade de São Paulo, São Paulo, Brazil.
| | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Medical Sciences, Toyoake, Aichi, 470-1192, Japan
| | | | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Medical Sciences, Toyoake, Aichi, 470-1192, Japan
| | - Luiz E Anelli
- Instituto de Geociências, Universidade de São Paulo, São Paulo, Brazil
| | - José A F Andrade
- Centro de Pesquisas Paleontológicas da Chapada do Araripe, Departamento Nacional de Produção Mineral, 63100-440, Crato, Brazil
| | - Keely Glass
- Department of Chemistry, Duke University, Durham, NC, 27708, USA
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Abstract
The sequence of decay in fern pinnules was tracked using the species Davallia canariensis. Taphonomic alterations in the sediment–water interface (control tanks) and in subaqueous conditions with microbial mats were compared. The decay sequences were similar in control and mat tanks; in both cases, pinnules preserved the shape throughout the four-month experience. However, the quality and integrity of tissues were greater in mats. In control tanks, in which we detected anoxic and neutral acid conditions, the appearance of a fungal–bacterial biofilm promoted mechanical (cell breakage and tissue distortions) and geochemical changes (infrequent mineralizations) on the external and internal pinnule tissues. In mats, characterized by stable dissolved oxygen and basic pH, pinnules became progressively entombed. These settings, together with the products derived from mat metabolisms (exopolymeric substances, proteins, and rich-Ca nucleation), promoted the integrity of external and internal tissues, and favored massive and diverse mineralization processes. The experience validates that the patterns of taphonomic alterations may be applied in fossil plants.
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