1
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Dallai L, Sharp ZD. A tipping point in stable isotope composition of Antarctic meteoric waters during Cenozoic glaciation. Nat Commun 2024; 15:4509. [PMID: 38802358 DOI: 10.1038/s41467-024-48811-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 05/10/2024] [Indexed: 05/29/2024] Open
Abstract
Triple oxygen isotopes of Cenozoic intrusive rocks emplaced along the Ross Sea coastline in Antarctica, reveal that meteoric-hydrothermal waters imprinted their stable isotope composition on mineral phases, leaving a clear record of oxygen and hydrogen isotope variations during the establishment of the polar cap. Calculated O- and H-isotope compositions of meteoric waters vary from -9 ± 2‰ and -92 ± 5‰ at 40 ± 0.6 Ma, to -30 and -234 ± 5‰ at 34 ± 1.9 Ma, and intersect the modern Global Meteoric Water Line. These isotopic variations likely depict the combined variations in temperature, humidity, and moisture source regions, resulting from rearrangement of oceanic currents and atmospheric cooling during the onset of continental ice cap. Here, we report a paleo-climatic proxy based on triple oxygen geochemistry of crystalline rocks that reveals changes in the hydrological cycle. We discuss the magnitude of temperature changes at high latitudes during the Eocene-Oligocene climatic transition.
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Affiliation(s)
- Luigi Dallai
- Dip. Scienze della Terra, Università degli Studi di Roma "Sapienza", Roma, Italy.
- CNR - IGG, Area della Ricerca di Pisa, Pisa, Italy.
| | - Zachary D Sharp
- Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, USA
- Center for Stable Isotopes, University of New Mexico, Albuquerque, NM, USA
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2
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Sullivan NB, Meyers SR, Levy RH, McKay RM, Golledge NR, Cortese G. Millennial-scale variability of the Antarctic ice sheet during the early Miocene. Proc Natl Acad Sci U S A 2023; 120:e2304152120. [PMID: 37722047 PMCID: PMC10523552 DOI: 10.1073/pnas.2304152120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 08/02/2023] [Indexed: 09/20/2023] Open
Abstract
Millennial-scale ice sheet variability (1-15 kyr periods) is well documented in the Quaternary, providing insight into critical atmosphere-ocean-cryosphere interactions that can inform the mechanism and pace of future climate change. Ice sheet variability at similar frequencies is comparatively less known and understood prior to the Quaternary during times, where higher atmospheric pCO2 and warmer climates prevailed, and continental-scale ice sheets were largely restricted to Antarctica. In this study, we evaluate a high-resolution clast abundance dataset (ice-rafted debris) that captures East Antarctic ice sheet variability in the western Ross Sea during the early Miocene. This dataset is derived from a 100 m-thick mudstone interval in the ANtarctic DRILLing (ANDRILL or AND) core 2A, which preserves a record of precession and eccentricity variability. The sedimentation rates are of appropriate resolution to also characterize the signature of robust, subprecession cyclicity. Strong sub-precession (~10 kyr) cyclicity is observed, with an amplitude modulation in lockstep with eccentricity, indicating a relationship between high-frequency Antarctic ice sheet dynamics and astronomical forcing. Bicoherence analysis indicates that many of the observed millennial-scale cycles (as short as 1.2 kyr) are associated with nonlinear interactions (combination or difference tones) between each other and the Milankovitch cycles. The presence of these cycles during the Miocene reveals the ubiquity of millennial-scale ice sheet variability and sheds light on the interactions between Earth's atmosphere, ocean, and ice in climates warmer than the Quaternary.
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Affiliation(s)
| | - Stephen R. Meyers
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI53706
| | - Richard H. Levy
- Antarctic Research Centre, Victoria University of Wellington, Wellington6012, New Zealand
- Geological and Nuclear Science, Lower Hutt5040, New Zealand
| | - Robert M. McKay
- Antarctic Research Centre, Victoria University of Wellington, Wellington6012, New Zealand
| | - Nicholas R. Golledge
- Antarctic Research Centre, Victoria University of Wellington, Wellington6012, New Zealand
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3
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Crichton KA, Wilson JD, Ridgwell A, Boscolo-Galazzo F, John EH, Wade BS, Pearson PN. What the geological past can tell us about the future of the ocean's twilight zone. Nat Commun 2023; 14:2376. [PMID: 37105972 PMCID: PMC10140295 DOI: 10.1038/s41467-023-37781-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 03/30/2023] [Indexed: 04/29/2023] Open
Abstract
Paleontological reconstructions of plankton community structure during warm periods of the Cenozoic (last 66 million years) reveal that deep-dwelling 'twilight zone' (200-1000 m) plankton were less abundant and diverse, and lived much closer to the surface, than in colder, more recent climates. We suggest that this is a consequence of temperature's role in controlling the rate that sinking organic matter is broken down and metabolized by bacteria, a process that occurs faster at warmer temperatures. In a warmer ocean, a smaller fraction of organic matter reaches the ocean interior, affecting food supply and dissolved oxygen availability at depth. Using an Earth system model that has been evaluated against paleo observations, we illustrate how anthropogenic warming may impact future carbon cycling and twilight zone ecology. Our findings suggest that significant changes are already underway, and without strong emissions mitigation, widespread ecological disruption in the twilight zone is likely by 2100, with effects spanning millennia thereafter.
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Affiliation(s)
- Katherine A Crichton
- School of Earth and Environmental Science, Cardiff University, Cardiff, UK.
- Now at Department of Geography, University of Exeter, Exeter, UK.
| | - Jamie D Wilson
- School of Earth Sciences, University of Bristol, Bristol, UK
- Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Andy Ridgwell
- Department of Earth and Planetary Sciences, University of California, Riverside, CA, USA
| | - Flavia Boscolo-Galazzo
- School of Earth and Environmental Science, Cardiff University, Cardiff, UK
- Now at MARUM, University of Bremen, Bremen, Germany
| | - Eleanor H John
- School of Earth and Environmental Science, Cardiff University, Cardiff, UK
| | - Bridget S Wade
- Department of Earth Sciences, University College London, London, UK
| | - Paul N Pearson
- School of Earth and Environmental Science, Cardiff University, Cardiff, UK
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4
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McCann HC, Sage RF. Seed size effects on plant establishment under low atmospheric CO2, with implications for seed size evolution. ANNALS OF BOTANY 2022; 130:825-834. [PMID: 36094296 PMCID: PMC9758303 DOI: 10.1093/aob/mcac112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 06/14/2022] [Accepted: 09/09/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND AIMS Low atmospheric CO2 concentration depresses photosynthesis and resource use efficiency, and therefore can inhibit phases of the life cycle such as seedling establishment. Seed reserves can compensate for photosynthetic inhibition by accelerating seedling growth. We therefore hypothesize that seedlings arising from large seeds show less inhibition from low atmospheric CO2 than young plants from small seeds. Seed size effects on seedling responses to low CO2 may also be enhanced in warm environments, due to greater photorespiration at high temperature. METHODS Phaseolus and Vigna seeds differing in mass by over two orders of magnitude were planted and grown for 14 d in growth chambers with CO2 concentrations of 370, 180 or 100 ppm, in thermal regimes of 25 °C/19 °C, 30 °C/24 °C or 35 °C/29 °C (day/night). We measured leaf area expansion, shoot growth and mortality of the seedlings arising from the variously sized seeds at 14 days after planting (14 DAP). KEY RESULTS Relative to small-seeded plants, large-seeded genotypes produced greater leaf area and shoot mass at 14 DAP across the range of CO2 treatments in the 25 °C/19 °C and 30 °C/24 °C regimes, and at 100 ppm in the 35 °C/29 °C treatment. The proportional decline in leaf area and seed mass with CO2 reduction was generally greater for seedlings arising from small than from large seeds. Reductions in leaf area due to CO2 reduction increased in the warmer temperature treatments. In the 35 °C/19 °C treatment at 100 ppm CO2, seedling mortality was greater in small- than in large-seeded genotypes, and the small-seeded genotypes were unable to exit the seedling stage by the end of the experiment. CONCLUSIONS The results support a hypothesis that seedlings from large seeds grow and establish better than seedlings from small seeds in warm, low CO2 environments. During low CO2 episodes in Earth's history, such as the past 30 million years, large seeds may have been favoured by natural selection in warm environments. With the recent rise in atmospheric CO2 due to human activities, trade-offs between seed size and number may already be affected, such that seed size today may be non-optimal in their natural habitats.
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Affiliation(s)
- Honour C McCann
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
- Max Planck Institute for Biology, Tübingen, Germany
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5
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Judd EJ, Tierney JE, Huber BT, Wing SL, Lunt DJ, Ford HL, Inglis GN, McClymont EL, O'Brien CL, Rattanasriampaipong R, Si W, Staitis ML, Thirumalai K, Anagnostou E, Cramwinckel MJ, Dawson RR, Evans D, Gray WR, Grossman EL, Henehan MJ, Hupp BN, MacLeod KG, O'Connor LK, Sánchez Montes ML, Song H, Zhang YG. The PhanSST global database of Phanerozoic sea surface temperature proxy data. Sci Data 2022; 9:753. [PMID: 36473868 PMCID: PMC9726822 DOI: 10.1038/s41597-022-01826-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 11/08/2022] [Indexed: 12/12/2022] Open
Abstract
Paleotemperature proxy data form the cornerstone of paleoclimate research and are integral to understanding the evolution of the Earth system across the Phanerozoic Eon. Here, we present PhanSST, a database containing over 150,000 data points from five proxy systems that can be used to estimate past sea surface temperature. The geochemical data have a near-global spatial distribution and temporally span most of the Phanerozoic. Each proxy value is associated with consistent and queryable metadata fields, including information about the location, age, and taxonomy of the organism from which the data derive. To promote transparency and reproducibility, we include all available published data, regardless of interpreted preservation state or vital effects. However, we also provide expert-assigned diagenetic assessments, ecological and environmental flags, and other proxy-specific fields, which facilitate informed and responsible reuse of the database. The data are quality control checked and the foraminiferal taxonomy has been updated. PhanSST will serve as a valuable resource to the paleoclimate community and has myriad applications, including evolutionary, geochemical, diagenetic, and proxy calibration studies.
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Affiliation(s)
- Emily J Judd
- Smithsonian National Museum of Natural History, Department of Paleobiology, Washington, DC, 20560, USA.
| | - Jessica E Tierney
- University of Arizona, Department of Geosciences, Tuscon, AZ, 85721, USA
| | - Brian T Huber
- Smithsonian National Museum of Natural History, Department of Paleobiology, Washington, DC, 20560, USA
| | - Scott L Wing
- Smithsonian National Museum of Natural History, Department of Paleobiology, Washington, DC, 20560, USA
| | - Daniel J Lunt
- University of Bristol, School of Geographical Sciences, Bristol, BS8 1SS, UK
| | - Heather L Ford
- Queen Mary University of London, School of Geography, London, E1 4NS, UK
| | - Gordon N Inglis
- University of Southampton, School of Ocean and Earth Science, National Oceanography Centre Southampton, Southampton, SO14 3ZH, UK
| | | | | | | | - Weimin Si
- Brown University, Department of Earth, Environmental and Planetary Sciences, Providence, RI, 02912, USA
| | - Matthew L Staitis
- University of Edinburgh, School of Geosciences, Edinburgh, EH8 9XP, UK
| | | | - Eleni Anagnostou
- GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148, Kiel, Germany
| | - Marlow Julius Cramwinckel
- University of Southampton, School of Ocean and Earth Science, National Oceanography Centre Southampton, Southampton, SO14 3ZH, UK
- Utrecht University, Department of Earth Sciences, Utrecht, 3584 CB, The Netherlands
| | - Robin R Dawson
- University of Massachusetts Amherst, Department of Geosciences, Amherst, MA, 01003, USA
| | - David Evans
- Goethe University Frankfurt, Institute of Geosciences, 60438, Frankfurt am Main, Germany
| | - William R Gray
- Université Paris-Saclay, Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France
| | - Ethan L Grossman
- Texas A&M University, Department of Geology and Geophysics, College Station, TX, 77843, USA
| | - Michael J Henehan
- GFZ German Research Centre for Geosciences, Section 3.3 Earth Surface Geochemistry, 14473, Potsdam, Germany
| | - Brittany N Hupp
- Oregon State University, College of Earth, Ocean and Atmospheric Sciences, Corvallis, OR, 97331, USA
| | - Kenneth G MacLeod
- University of Missouri, Department of Geological Sciences, Columbia, MO, 65211, USA
| | - Lauren K O'Connor
- University of Manchester, Department of Earth and Environmental Sciences, Manchester, M13 9PL, UK
| | | | - Haijun Song
- China University of Geosciences, State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, Wuhan, 430074, China
| | - Yi Ge Zhang
- Texas A&M University, Department of Oceanography, College Station, TX, 77843, USA
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6
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Auderset A, Moretti S, Taphorn B, Ebner PR, Kast E, Wang XT, Schiebel R, Sigman DM, Haug GH, Martínez-García A. Enhanced ocean oxygenation during Cenozoic warm periods. Nature 2022; 609:77-82. [PMID: 36045236 PMCID: PMC9433325 DOI: 10.1038/s41586-022-05017-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/09/2022] [Indexed: 11/09/2022]
Abstract
Dissolved oxygen (O2) is essential for most ocean ecosystems, fuelling organisms’ respiration and facilitating the cycling of carbon and nutrients. Oxygen measurements have been interpreted to indicate that the ocean’s oxygen-deficient zones (ODZs) are expanding under global warming1,2. However, models provide an unclear picture of future ODZ change in both the near term and the long term3–6. The paleoclimate record can help explore the possible range of ODZ changes in warmer-than-modern periods. Here we use foraminifera-bound nitrogen (N) isotopes to show that water-column denitrification in the eastern tropical North Pacific was greatly reduced during the Middle Miocene Climatic Optimum (MMCO) and the Early Eocene Climatic Optimum (EECO). Because denitrification is restricted to oxygen-poor waters, our results indicate that, in these two Cenozoic periods of sustained warmth, ODZs were contracted, not expanded. ODZ contraction may have arisen from a decrease in upwelling-fuelled biological productivity in the tropical Pacific, which would have reduced oxygen demand in the subsurface. Alternatively, invigoration of deep-water ventilation by the Southern Ocean may have weakened the ocean’s ‘biological carbon pump’, which would have increased deep-ocean oxygen. The mechanism at play would have determined whether the ODZ contractions occurred in step with the warming or took centuries or millennia to develop. Thus, although our results from the Cenozoic do not necessarily apply to the near-term future, they might imply that global warming may eventually cause ODZ contraction. By using foraminifera-bound nitrogen isotopes, it is shown that, during two warm periods of the Cenozoic, oxygen-deficient zones contracted rather than expanded, suggesting that global warming may not necessarily lead to increased oceanic anoxia.
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Affiliation(s)
- Alexandra Auderset
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany. .,Department of Earth Sciences, ETH Zurich, Zurich, Switzerland.
| | - Simone Moretti
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany.,Department of Earth Sciences, ETH Zurich, Zurich, Switzerland
| | - Björn Taphorn
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Pia-Rebecca Ebner
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Emma Kast
- Department of Geosciences, Princeton University, Princeton, NJ, USA.,Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - Xingchen T Wang
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA, USA
| | - Ralf Schiebel
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Daniel M Sigman
- Department of Geosciences, Princeton University, Princeton, NJ, USA
| | - Gerald H Haug
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany.,Department of Earth Sciences, ETH Zurich, Zurich, Switzerland
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7
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Shartau RB, Harter TS, Baker DW, Aboagye DL, Allen PJ, Val AL, Crossley DA, Kohl ZF, Hedrick MS, Damsgaard C, Brauner CJ. Acute CO 2 tolerance in fishes is associated with air breathing but not the Root effect, red cell βNHE, or habitat. Comp Biochem Physiol A Mol Integr Physiol 2022; 274:111304. [PMID: 36049728 DOI: 10.1016/j.cbpa.2022.111304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 08/03/2022] [Accepted: 08/07/2022] [Indexed: 12/01/2022]
Abstract
High CO2 (hypercapnia) can impose significant physiological challenges associated with acid-base regulation in fishes, impairing whole animal performance and survival. Unlike other environmental conditions such as temperature and O2, the acute CO2 tolerance thresholds of fishes are not understood. While some fish species are highly tolerant, the extent of acute CO2 tolerance and the associated physiological and ecological traits remain largely unknown. To investigate this, we used a recently developed ramping assay, termed the Carbon Dioxide maximum (CDmax), that increases CO2 exposure until loss of equilibrium (LOE) is observed. We investigated if there was a relationship between CO2 tolerance and the Root effect, β-adrenergic sodium proton exchanger (βNHE), air-breathing, and fish habitat in 17 species. We hypothesized that CO2 tolerance would be higher in fishes that lack both a Root effect and βNHE, breathe air, and reside in tropical habitats. Our results showed that CDmax ranged from 2.7 to 26.7 kPa, while LOE was never reached in four species at the maximum PCO2 we could measure (26.7 kPa); CO2 tolerance was only associated with air-breathing, but not the presence of a Root effect or a red blood cell (RBC) βNHE, or fish habitat. This study demonstrates that the diverse group of fishes investigated here are incredibly tolerant of CO2 and that although this tolerance is associated with air-breathing, further investigations are required to understand the basis for CO2 tolerance.
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Affiliation(s)
- R B Shartau
- Department of Biology, The University of Texas at Tyler, Tyler, TX, USA; Department of Zoology, University of British Columbia, Vancouver, BC, Canada.
| | - T S Harter
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada; Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, CA, USA.
| | - D W Baker
- Department of Fisheries and Aquaculture, Vancouver Island University, Nanaimo, BC, Canada.
| | - D L Aboagye
- Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, Starkville, MS, USA
| | - P J Allen
- Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, Starkville, MS, USA.
| | - A L Val
- Laboratory of Ecophysiology and Molecular Evolution, Brazilian National Institute for Research of the Amazon (INPA), Manaus, AM, Brazil
| | - D A Crossley
- Department of Biological Sciences, University of North Texas, Denton, TX, USA.
| | - Z F Kohl
- Department of Biological Sciences, University of North Texas, Denton, TX, USA
| | - M S Hedrick
- Department of Biological Sciences, California State University, East Bay, Hayward, CA, USA.
| | - C Damsgaard
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark.
| | - C J Brauner
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada.
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8
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Dowsett H, Jacobs P, de Mutsert K. Using paleoecological data to inform decision making: A deep-time perspective. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.972179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Latest climate models project conditions for the end of this century that are generally outside of the human experience. These future conditions affect the resilience and sustainability of ecosystems, alter biogeographic zones, and impact biodiversity. Deep-time records of paleoclimate provide insight into the climate system over millions of years and provide examples of conditions very different from the present day, and in some cases similar to model projections for the future. In addition, the deep-time paleoecologic and sedimentologic archives provide insight into how species and habitats responded to past climate conditions. Thus, paleoclimatology provides essential context for the scientific understanding of climate change needed to inform resource management policy decisions. The Pliocene Epoch (5.3–2.6 Ma) is the most recent deep-time interval with relevance to future global warming. Analysis of marine sediments using a combination of paleoecology, biomarkers, and geochemistry indicates a global mean annual temperature for the Late Pliocene (3.6–2.6 Ma) ∼3°C warmer than the preindustrial. However, the inability of state-of-the-art climate models to capture some key regional features of Pliocene warming implies future projections using these same models may not span the full range of plausible future climate conditions. We use the Late Pliocene as one example of a deep-time interval relevant to management of biodiversity and ecosystems in a changing world. Pliocene reconstructed sea surface temperatures are used to drive a marine ecosystem model for the North Atlantic Ocean. Given that boundary conditions for the Late Pliocene are roughly analogous to present day, driving the marine ecosystem model with Late Pliocene paleoenvironmental conditions allows policymakers to consider a future ocean state and associated fisheries impacts independent of climate models, informed directly by paleoclimate information.
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9
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Abstract
Archaeal membrane lipids are widely used for paleotemperature reconstructions, yet these molecular fossils also bear rich information about ecology and evolution of marine ammonia-oxidizing archaea (AOA). Here we identified thermal and nonthermal behaviors of archaeal glycerol dialkyl glycerol tetraethers (GDGTs) by comparing the GDGT-based temperature index (TEX86) to the ratio of GDGTs with two and three cyclopentane rings (GDGT-2/GDGT-3). Thermal-dependent biosynthesis should increase TEX86 and decrease GDGT-2/GDGT-3 when the ambient temperature increases. This presumed temperature-dependent (PTD) trend is observed in GDGTs derived from cultures of thermophilic and mesophilic AOA. The distribution of GDGTs in suspended particulate matter (SPM) and sediments collected from above the pycnocline-shallow water samples-also follows the PTD trend. These similar GDGT distributions between AOA cultures and shallow water environmental samples reflect shallow ecotypes of marine AOA. While there are currently no cultures of deep AOA clades, GDGTs derived from deep water SPM and marine sediment samples exhibit nonthermal behavior deviating from the PTD trend. The presence of deep AOA increases the GDGT-2/GDGT-3 ratio and distorts the temperature-controlled correlation between GDGT-2/GDGT-3 and TEX86. We then used Gaussian mixture models to statistically characterize these diagnostic patterns of modern AOA ecology from paleo-GDGT records to infer the evolution of marine AOA from the Mid-Mesozoic to the present. Long-term GDGT-2/GDGT-3 trends suggest a suppression of today's deep water marine AOA during the Mesozoic-early Cenozoic greenhouse climates. Our analysis provides invaluable insights into the evolutionary timeline and the expansion of AOA niches associated with major oceanographic and climate changes.
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10
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Late Miocene Tarim desert wetting linked with eccentricity minimum and East Asian monsoon weakening. Nat Commun 2022; 13:3977. [PMID: 35803935 PMCID: PMC9270403 DOI: 10.1038/s41467-022-31577-w] [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: 06/17/2021] [Accepted: 06/23/2022] [Indexed: 11/08/2022] Open
Abstract
Periodic wetting is an inherent feature of many monsoon marginal region deserts. Previous studies consistently demonstrate desert wetting during times of Earth's high orbital eccentricity and strong summer monsoon. Here we report the first evidence demonstrating desert wetting during Earth's low orbital eccentricity from the late Miocene strata of the northwestern Tarim Basin of northern China, which is commonly thought to be beyond the range of Asian monsoon precipitation. Using mechanisms for modern Tarim wetting as analogs, we propose that East Asian summer monsoon weakening enhanced westward moisture transport and caused opposite desert wetting pattern to that observed in monsoon marginal region deserts. This inference is supported by our model simulations. This result has far-reaching implications for understanding environmental variations in non-monsoonal deserts in the next few thousands of years under high atmospheric CO2 content and low eccentricity.
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11
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Galushchinskiy A, González-Gómez R, McCarthy K, Farràs P, Savateev A. Progress in Development of Photocatalytic Processes for Synthesis of Fuels and Organic Compounds under Outdoor Solar Light. ENERGY & FUELS : AN AMERICAN CHEMICAL SOCIETY JOURNAL 2022; 36:4625-4639. [PMID: 35558990 PMCID: PMC9082502 DOI: 10.1021/acs.energyfuels.2c00178] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/18/2022] [Indexed: 05/19/2023]
Abstract
With photovoltaics becoming a mature, commercially feasible technology, society is willing to allocate resources for developing and deploying new technologies based on using solar light. Analysis of projects supported by the European Commission in the past decade indicates exponential growth of funding to photocatalytic (PC) and photoelectrocatalytic (PEC) technologies that aim either at technology readiness levels (TRLs) TRL 1-3 or TRL > 3, with more than 75 Mio€ allocated from the year 2019 onward. This review provides a summary of PC and PEC processes for the synthesis of bulk commodities such as solvents and fuels, as well as chemicals for niche applications. An overview of photoreactors for photocatalysis on a larger scale is provided. The review rounds off with the summary of reactions performed at lab scale under natural outdoor solar light to illustrate conceptual opportunities offered by solar-driven chemistry beyond the reduction of CO2 and water splitting. The authors offer their vision of the impact of this area of research on society and the economy.
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Affiliation(s)
- Alexey Galushchinskiy
- Department
of Colloid Chemistry, Max Planck Institute
of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Roberto González-Gómez
- School
of Chemistry, Ryan Institute, National University
of Ireland, Galway H91 CF50, Ireland
| | - Kathryn McCarthy
- School
of Chemistry, Ryan Institute, National University
of Ireland, Galway H91 CF50, Ireland
| | - Pau Farràs
- School
of Chemistry, Ryan Institute, National University
of Ireland, Galway H91 CF50, Ireland
| | - Aleksandr Savateev
- Department
of Colloid Chemistry, Max Planck Institute
of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
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12
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Environmental Factors Affecting Feather Taphonomy. BIOLOGY 2022; 11:biology11050703. [PMID: 35625431 PMCID: PMC9138376 DOI: 10.3390/biology11050703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 11/16/2022]
Abstract
The exceptional preservation of feathers in the fossil record has led to a better understanding of both phylogeny and evolution. Here we address factors that may have contributed to the preservation of feathers in ancient organisms using experimental taphonomy. We show that the atmospheres of the Mesozoic, known to be elevated in both CO2 and with temperatures above present levels, may have contributed to the preservation of these soft tissues by facilitating rapid precipitation of hydroxy- or carbonate hydroxyapatite, thus outpacing natural degradative processes. Data also support that that microbial degradation was enhanced in elevated CO2, but mineral deposition was also enhanced, contributing to preservation by stabilizing the organic components of feathers.
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13
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Lambie S, Steenbergen KG, Gaston N, Paulus B. Clustering of metal dopants in defect sites of graphene-based materials. Phys Chem Chem Phys 2021; 24:98-111. [PMID: 34889923 DOI: 10.1039/d1cp05008g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Single-atom catalysts are promising candidates for many industrial reactions. However, making true single-atom catalysts is an experimental dilemma, due to the difficulty of keeping dopant single atoms stable at temperature and under pressure. This difficulty can lead to clustering of the metal dopant atoms in defect sites. However, the electronic and geometric structure of sub-nanoscale clusters in single-atom defects has not yet been explored. Furthermore, recent studies have proven sub-nanoscale clusters of dopants in single-atom defect sites can be equally good or better catalysts than their single-atom counterparts. Here, a comprehensive DFT study is undertaken to determine the geometric and electronic structure effects that influence clustering of noble and p-block dopants in C3- and N4-defect sites in graphene-based systems. We find that the defect site is the primary driver in determining clustering dynamics in these systems.
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Affiliation(s)
- Stephanie Lambie
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Physics, University of Auckland, Private Bag 92019, Auckland, New Zealand. .,Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany.
| | - Krista G Steenbergen
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand
| | - Nicola Gaston
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Physics, University of Auckland, Private Bag 92019, Auckland, New Zealand.
| | - Beate Paulus
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany.
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14
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Ao H, Liebrand D, Dekkers MJ, Zhang P, Song Y, Liu Q, Jonell TN, Sun Q, Li X, Li X, Qiang X, An Z. Eccentricity-paced monsoon variability on the northeastern Tibetan Plateau in the Late Oligocene high CO 2 world. SCIENCE ADVANCES 2021; 7:eabk2318. [PMID: 34910508 PMCID: PMC8673770 DOI: 10.1126/sciadv.abk2318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/28/2021] [Indexed: 06/14/2023]
Abstract
Constraining monsoon variability and dynamics in the warm unipolar icehouse world of the Late Oligocene can provide important clues to future climate responses to global warming. Here, we present a ~4-thousand year (ka) resolution rubidium-to-strontium ratio and magnetic susceptibility records between 28.1 and 24.1 million years ago from a distal alluvial sedimentary sequence in the Lanzhou Basin (China) on the northeastern Tibetan Plateau margin. These Asian monsoon precipitation records exhibit prominent short (~110-ka) and long (405-ka) eccentricity cycles throughout the Late Oligocene, with a weak expression of obliquity (41-ka) and precession (19-ka and 23-ka) cycles. We conclude that a combination of eccentricity-modulated low-latitude summer insolation and glacial-interglacial Antarctic Ice Sheet fluctuations drove the eccentricity-paced precipitation variability on the northeastern Tibetan Plateau in the Late Oligocene high CO2 world by governing regional temperatures, water vapor loading in the western Pacific and Indian Oceans, and the Asian monsoon intensity and displacement.
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Affiliation(s)
- Hong Ao
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Diederik Liebrand
- National Oceanography Centre, European Way, SO14 3ZH Southampton, UK
- PalaeoClimate.Science, 27 Granby Grove, SO17 3RY, Southampton, UK
| | - Mark J. Dekkers
- Paleomagnetic Laboratory Fort Hoofddijk, Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Peng Zhang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Yougui Song
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Qingsong Liu
- Centre for Marine Magnetism (CM2), Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Tara N. Jonell
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow, UK
| | - Qiang Sun
- College of Geology and Environment, Xi’an University of Science and Technology, Xi’an, China
| | - Xinzhou Li
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Xinxia Li
- School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan, China
| | - Xiaoke Qiang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China
| | - Zhisheng An
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
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15
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Ao H, Rohling EJ, Zhang R, Roberts AP, Holbourn AE, Ladant JB, Dupont-Nivet G, Kuhnt W, Zhang P, Wu F, Dekkers MJ, Liu Q, Liu Z, Xu Y, Poulsen CJ, Licht A, Sun Q, Chiang JCH, Liu X, Wu G, Ma C, Zhou W, Jin Z, Li X, Li X, Peng X, Qiang X, An Z. Global warming-induced Asian hydrological climate transition across the Miocene-Pliocene boundary. Nat Commun 2021; 12:6935. [PMID: 34836960 PMCID: PMC8626456 DOI: 10.1038/s41467-021-27054-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 11/02/2021] [Indexed: 12/02/2022] Open
Abstract
Across the Miocene-Pliocene boundary (MPB; 5.3 million years ago, Ma), late Miocene cooling gave way to the early-to-middle Pliocene Warm Period. This transition, across which atmospheric CO2 concentrations increased to levels similar to present, holds potential for deciphering regional climate responses in Asia-currently home to more than half of the world's population- to global climate change. Here we find that CO2-induced MPB warming both increased summer monsoon moisture transport over East Asia, and enhanced aridification over large parts of Central Asia by increasing evaporation, based on integration of our ~1-2-thousand-year (kyr) resolution summer monsoon records from the Chinese Loess Plateau aeolian red clay with existing terrestrial records, land-sea correlations, and climate model simulations. Our results offer palaeoclimate-based support for 'wet-gets-wetter and dry-gets-drier' projections of future regional hydroclimate responses to sustained anthropogenic forcing. Moreover, our high-resolution monsoon records reveal a dynamic response to eccentricity modulation of solar insolation, with predominant 405-kyr and ~100-kyr periodicities between 8.1 and 3.4 Ma.
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Affiliation(s)
- Hong Ao
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China.
| | - Eelco J Rohling
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, UK
| | - Ran Zhang
- Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
| | - Andrew P Roberts
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
| | - Ann E Holbourn
- Institute of Geosciences, Christian-Albrechts-University, Kiel, Germany
| | - Jean-Baptiste Ladant
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
| | - Guillaume Dupont-Nivet
- Géosciences Rennes, UMR-CNRS 6118, University Rennes, Rennes, France
- Department of Geosciences, Potsdam University, Potsdam, Germany
| | - Wolfgang Kuhnt
- Institute of Geosciences, Christian-Albrechts-University, Kiel, Germany
| | - Peng Zhang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Feng Wu
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
| | - Mark J Dekkers
- Paleomagnetic Laboratory 'Fort Hoofddijk', Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Qingsong Liu
- Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Zhonghui Liu
- Department of Earth Sciences, University of Hong Kong, Hong Kong, China
| | - Yong Xu
- Xi'an Center of Geological Survey, China Geological Survey, Xi'an, China
| | - Christopher J Poulsen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Alexis Licht
- Department of Earth and Space Sciences, University of Washington, Seattle, WA, USA
| | - Qiang Sun
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, China
| | - John C H Chiang
- Department of Geography, University of California, Berkeley, CA, USA
| | - Xiaodong Liu
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
| | - Guoxiong Wu
- Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Chao Ma
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu Universityof Technology, Chengdu, China
| | - Weijian Zhou
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Zhangdong Jin
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Xinxia Li
- School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan, China
| | - Xinzhou Li
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
| | - Xianzhe Peng
- School of Information Management, Nanjing University, Nanjing, China
| | - Xiaoke Qiang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
| | - Zhisheng An
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
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16
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The Drake Passage opening from an experimental fluid dynamics point of view. Sci Rep 2021; 11:19951. [PMID: 34620925 PMCID: PMC8497466 DOI: 10.1038/s41598-021-99123-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 09/09/2021] [Indexed: 11/08/2022] Open
Abstract
Pronounced global cooling around the Eocene–Oligocene transition (EOT) was a pivotal event in Earth’s climate history, controversially associated with the opening of the Drake Passage. Using a physical laboratory model we revisit the fluid dynamics of this marked reorganization of ocean circulation. Here we show, seemingly contradicting paleoclimate records, that in our experiments opening the pathway yields higher values of mean water surface temperature than the “closed” configuration. This mismatch points to the importance of the role ice albedo feedback plays in the investigated EOT-like transition, a component that is not captured in the laboratory model. Our conclusion is supported by numerical simulations performed in a global climate model (GCM) of intermediate complexity, where both “closed” and “open” configurations were explored, with and without active sea ice dynamics. The GCM results indicate that sea surface temperatures would change in the opposite direction following an opening event in the two sea ice dynamics settings, and the results are therefore consistent both with the laboratory experiment (slight warming after opening) and the paleoclimatic data (pronounced cooling after opening). It follows that in the hypothetical case of an initially ice-free Antarctica the continent could have become even warmer after the opening, a scenario not indicated by paleotemperature reconstructions.
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17
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de Vries D, Heritage S, Borths MR, Sallam HM, Seiffert ER. Widespread loss of mammalian lineage and dietary diversity in the early Oligocene of Afro-Arabia. Commun Biol 2021; 4:1172. [PMID: 34621013 PMCID: PMC8497553 DOI: 10.1038/s42003-021-02707-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 09/21/2021] [Indexed: 11/16/2022] Open
Abstract
Diverse lines of geological and geochemical evidence indicate that the Eocene-Oligocene transition (EOT) marked the onset of a global cooling phase, rapid growth of the Antarctic ice sheet, and a worldwide drop in sea level. Paleontologists have established that shifts in mammalian community structure in Europe and Asia were broadly coincident with these events, but the potential impact of early Oligocene climate change on the mammalian communities of Afro-Arabia has long been unclear. Here we employ dated phylogenies of multiple endemic Afro-Arabian mammal clades (anomaluroid and hystricognath rodents, anthropoid and strepsirrhine primates, and carnivorous hyaenodonts) to investigate lineage diversification and loss since the early Eocene. These analyses provide evidence for widespread mammalian extinction in the early Oligocene of Afro-Arabia, with almost two-thirds of peak late Eocene diversity lost in these clades by ~30 Ma. Using homology-free dental topographic metrics, we further demonstrate that the loss of Afro-Arabian rodent and primate lineages was associated with a major reduction in molar occlusal topographic disparity, suggesting a correlated loss of dietary diversity. These results raise new questions about the relative importance of global versus local influences in shaping the evolutionary trajectories of Afro-Arabia's endemic mammals during the Oligocene.
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Affiliation(s)
- Dorien de Vries
- Ecosystems and Environment Research Centre, School of Science, Engineering and Environment, University of Salford, Manchester, UK
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Steven Heritage
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY, 11794, USA
- Duke Lemur Center Museum of Natural History, Durham, NC, 27705, USA
| | - Matthew R Borths
- Duke Lemur Center Museum of Natural History, Durham, NC, 27705, USA
| | - Hesham M Sallam
- Duke Lemur Center Museum of Natural History, Durham, NC, 27705, USA
- Mansoura University Vertebrate Paleontology, Department of Geology, Faculty of Science, Mansoura, Egypt
- Institute of Global Health and Human Ecology (I-GHHE), School of Sciences and Engineering, American University in Cairo, New Cairo, Egypt
| | - Erik R Seiffert
- Duke Lemur Center Museum of Natural History, Durham, NC, 27705, USA.
- Department of Integrative Anatomical Sciences, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA.
- Department of Mammalogy, Natural History Museum of Los Angeles County, Los Angeles, CA, 90007, USA.
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18
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Thomson JR, Holden PB, Anand P, Edwards NR, Porchier CA, Harris NBW. Tectonic and climatic drivers of Asian monsoon evolution. Nat Commun 2021; 12:4022. [PMID: 34188033 PMCID: PMC8242090 DOI: 10.1038/s41467-021-24244-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 05/26/2021] [Indexed: 11/23/2022] Open
Abstract
Asian Monsoon rainfall supports the livelihood of billions of people, yet the relative importance of different drivers remains an issue of great debate. Here, we present 30 million-year model-based reconstructions of Indian summer monsoon and South East Asian monsoon rainfall at millennial resolution. We show that precession is the dominant direct driver of orbital variability, although variability on obliquity timescales is driven through the ice sheets. Orographic development dominated the evolution of the South East Asian monsoon, but Indian summer monsoon evolution involved a complex mix of contributions from orography (39%), precession (25%), atmospheric CO2 (21%), ice-sheet state (5%) and ocean gateways (5%). Prior to 15 Ma, the Indian summer monsoon was broadly stable, albeit with substantial orbital variability. From 15 Ma to 5 Ma, strengthening was driven by a combination of orography and glaciation, while closure of the Panama gateway provided the prerequisite for the modern Indian summer monsoon state through a strengthened Atlantic meridional overturning circulation.
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Affiliation(s)
| | - Philip B Holden
- School of Environment, Earth & Ecosystem Sciences, The Open University, Milton Keynes, UK.
| | - Pallavi Anand
- School of Environment, Earth & Ecosystem Sciences, The Open University, Milton Keynes, UK
| | - Neil R Edwards
- School of Environment, Earth & Ecosystem Sciences, The Open University, Milton Keynes, UK
- Cambridge Centre for Energy, Environment and Natural Resource Governance, University of Cambridge, Cambridge, UK
| | - Cécile A Porchier
- School of Environment, Earth & Ecosystem Sciences, The Open University, Milton Keynes, UK
- Department of Geography, University College London, London, UK
| | - Nigel B W Harris
- School of Environment, Earth & Ecosystem Sciences, The Open University, Milton Keynes, UK
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19
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Almeida FC, Amador LI, Giannini NP. Explosive radiation at the origin of Old World fruit bats (Chiroptera, Pteropodidae). ORG DIVERS EVOL 2021. [DOI: 10.1007/s13127-021-00480-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Paleoceanographic Perturbations and the Marine Carbonate System during the Middle to Late Miocene Carbonate Crash—A Critical Review. GEOSCIENCES 2021. [DOI: 10.3390/geosciences11020094] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study intends to review and assess the middle to late Miocene Carbonate Crash (CC) events in the low to mid latitudes of the Pacific, Indian, Caribbean and Atlantic Oceans as part of the global paleoceanographic reorganisations between 12 and 9 Ma with an emphasis on record preservation and their relation to mass accumulation rates (MAR). In the Eastern Pacific the accumulation changes in carbonate and opal probably reflect an El-Niño-like state of low productivity, which marks the beginning of the CC-event (11.5 Ma), followed by decreased preservation and influx of corrosive bottom waters (10.3 to 10.1 Ma). At the same time in the Atlantic, carbonate preservation considerably increases, suggesting basin-to-basin fractionation. The low-latitude Indian Ocean, the Pacific and the Caribbean are all characterised by a similar timing of preservation increase starting at ~9.6–9.4 Ma, while their MARs show drastic changes with different timing of events. The Atlantic preservation pattern shows an increase as early as 11.5 Ma and becomes even better after 10.1 Ma. The shallow Indian Ocean (Mascarene plateau) is characterised by low carbonate accumulation throughout and increasing preservation after 9.4 Ma. At the same time, the preservation in the Atlantic, including the Caribbean, is increasing due to enhanced North Atlantic deep-water formation, leading to the increase in carbonate accumulation at 10 Ma. Moreover, the shoaling of the Central American Isthmus might have helped to enhance Caribbean preservation after 9.4 Ma. Lower nannoplankton productivity in the Atlantic should have additionally contributed to low mass accumulation rates during the late CC-interval. Overall, it can be inferred that these carbonate minima events during the Miocene may be the result of decreased surface ocean productivity and oceanographically driven increased seafloor dissolution.
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21
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Komar N, Zeebe RE. Reconciling atmospheric CO 2, weathering, and calcite compensation depth across the Cenozoic. SCIENCE ADVANCES 2021; 7:eabd4876. [PMID: 33523943 PMCID: PMC10671158 DOI: 10.1126/sciadv.abd4876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 12/03/2020] [Indexed: 05/13/2023]
Abstract
The Cenozoic era (66 to 0 million years) is marked by long-term aberrations in carbon cycling and large climatic shifts, some of which challenge the current understanding of carbon cycle dynamics. Here, we investigate possible mechanisms responsible for the observed long-term trends by using a novel approach that features a full-fledged ocean carbonate chemistry model. Using a compilation of pCO2, pH, and calcite compensation depth (CCD) observational evidence and a suite of simulations, we reconcile long-term Cenozoic climate and CCD trends. We show that the CCD response was decoupled from changes in silicate and carbonate weathering rates, challenging the continental uplift hypothesis. The two dominant mechanisms for decoupling are shelf-basin carbonate burial fractionation combined with proliferation of pelagic calcifiers. The temperature effect on remineralization rates of marine organic matter also plays a critical role in controlling the carbon cycle dynamics, especially during the warmer periods of the Cenozoic.
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Affiliation(s)
- Nemanja Komar
- School of Ocean and Earth Science and Technology, Department of Oceanography, University of Hawaii, 1000 Pope Road, Honolulu, HI 96822, USA.
| | - Richard E Zeebe
- School of Ocean and Earth Science and Technology, Department of Oceanography, University of Hawaii, 1000 Pope Road, Honolulu, HI 96822, USA
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22
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Solórzano-Kraemer MM, Delclòs X, Engel MS, Peñalver E. A revised definition for copal and its significance for palaeontological and Anthropocene biodiversity-loss studies. Sci Rep 2020; 10:19904. [PMID: 33199762 PMCID: PMC7669904 DOI: 10.1038/s41598-020-76808-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 11/02/2020] [Indexed: 11/09/2022] Open
Abstract
The early fossilization steps of natural resins and associated terminology are a subject of constant debate. Copal and resin are archives of palaeontological and historical information, and their study is critical to the discovery of new and/or recently extinct species and to trace changes in forests during the Holocene. For such studies, a clear, suitable definition for copal is vital and is herein established. We propose an age range for copal (2.58 Ma—1760 AD), including Pleistocene and Holocene copals, and the novel term "Defaunation resin", defined as resin produced after the commencement of the Industrial Revolution. Defaunation resin is differentiated from Holocene copal as it was produced during a period of intense human transformative activities. Additionally, the “Latest Amber Bioinclusions Gap” (LABG) since the late Miocene to the end of the Pleistocene is hereby newly defined, and is characterized by its virtual absence of bioinclusions and the consequent lack of palaeontological information, which in part explains the historical differentiation between amber and copal. Crucial time intervals in the study of resin production, and of the biodiversity that could be contained, are now clarified, providing a framework for and focusing future research on bioinclusions preserved in copal and resin.
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Affiliation(s)
- Mónica M Solórzano-Kraemer
- Palaeontology and Historical Geology, Senckenberg Research Institute, 60325, Frankfurt am Main, Germany.
| | - Xavier Delclòs
- Departament de Dinàmica de la Terra i de l'Oceà and Institut de Recerca de la Biodiversitat (IRBio), Facultat de Ciències de la Terra, Universitat de Barcelona, 08028, Barcelona, Spain
| | - Michael S Engel
- Division of Entomology, Natural History Museum, and Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA.,Division of Invertebrate Zoology, American Museum of Natural History, New York, NY, 10024, USA
| | - Enrique Peñalver
- Instituto Geológico y Minero de España (Museo Geominero), 46004, Valencia, Spain
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23
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Ao H, Dupont-Nivet G, Rohling EJ, Zhang P, Ladant JB, Roberts AP, Licht A, Liu Q, Liu Z, Dekkers MJ, Coxall HK, Jin Z, Huang C, Xiao G, Poulsen CJ, Barbolini N, Meijer N, Sun Q, Qiang X, Yao J, An Z. Orbital climate variability on the northeastern Tibetan Plateau across the Eocene-Oligocene transition. Nat Commun 2020; 11:5249. [PMID: 33067447 PMCID: PMC7567875 DOI: 10.1038/s41467-020-18824-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/16/2020] [Indexed: 11/08/2022] Open
Abstract
The first major build-up of Antarctic glaciation occurred in two consecutive stages across the Eocene-Oligocene transition (EOT): the EOT-1 cooling event at ~34.1-33.9 Ma and the Oi-1 glaciation event at ~33.8-33.6 Ma. Detailed orbital-scale terrestrial environmental responses to these events remain poorly known. Here we present magnetic and geochemical climate records from the northeastern Tibetan Plateau margin that are dated precisely from ~35.5 to 31 Ma by combined magneto- and astro-chronology. These records suggest a hydroclimate transition at ~33.7 Ma from eccentricity dominated cycles to oscillations paced by a combination of eccentricity, obliquity, and precession, and confirm that major Asian aridification and cooling occurred at Oi-1. We conclude that this terrestrial orbital response transition coincided with a similar transition in the marine benthic δ18O record for global ice volume and deep-sea temperature variations. The dramatic reorganization of the Asian climate system coincident with Oi-1 was, thus, a response to coeval atmospheric CO2 decline and continental-scale Antarctic glaciation.
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Affiliation(s)
- Hong Ao
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
- CAS Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an, China.
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China.
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China.
| | - Guillaume Dupont-Nivet
- Université de Rennes, CNRS, Géosciences Rennes, UMR, 6118, Rennes, France.
- Key Laboratory of Orogenic Belts and Crustal Evolution, Peking University, Beijing, China.
- Universität Potsdam, Institute of Geosciences, Potsdam, Germany.
| | - Eelco J Rohling
- Research School of Earth Sciences, Australian National University, Canberra, Australia
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, UK
| | - Peng Zhang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
- Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Jean-Baptiste Ladant
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Andrew P Roberts
- Research School of Earth Sciences, Australian National University, Canberra, Australia
| | - Alexis Licht
- Department of Earth and Space Sciences, University of Washington, Seattle, USA
| | - Qingsong Liu
- Centre for Marine Magnetism (CM2), Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Zhonghui Liu
- Department of Earth Sciences, University of Hong Kong, Hong Kong, China
| | - Mark J Dekkers
- Paleomagnetic Laboratory 'Fort Hoofddijk', Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Helen K Coxall
- Department of Geological Sciences, Stockholm University, Stockholm, Sweden
| | - Zhangdong Jin
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
- CAS Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, China
| | - Chunju Huang
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Guoqiao Xiao
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Christopher J Poulsen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Natasha Barbolini
- Department of Ecosystem and Landscape Dynamics, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Niels Meijer
- Universität Potsdam, Institute of Geosciences, Potsdam, Germany
| | - Qiang Sun
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, China
| | - Xiaoke Qiang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
| | - Jiao Yao
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
| | - Zhisheng An
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
- CAS Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an, China.
- Interdisciplinary Research Center of Earth Science Frontier, Beijing Normal University, Beijing, China.
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24
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Köhler P, van de Wal RSW. Interglacials of the Quaternary defined by northern hemispheric land ice distribution outside of Greenland. Nat Commun 2020; 11:5124. [PMID: 33046715 PMCID: PMC7550566 DOI: 10.1038/s41467-020-18897-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/18/2020] [Indexed: 11/16/2022] Open
Abstract
Glacial/interglacial dynamics during the Quaternary were suggested to be mainly driven by obliquity (41-kyr periodicity), including irregularities during the last 1 Myr that resulted in on average 100-kyr cycles. Here, we investigate this so-called Mid-Pleistocene Transition via model-based deconvolution of benthic δ18O, redefining interglacials by lack of substantial northern hemispheric land ice outside of Greenland. We find that in 67%, 88% and 52% of the obliquity cycles during the early, middle and late Quaternary, respectively, a glacial termination is realized leading to irregular appearances of new interglacials during various parts of the last 2.6 Myr. This finding suggests that the proposed idea of terminations leading to new interglacials in the Quaternary as obliquity driven with growing influence of land ice volume on the timing of deglaciations during the last 1 Myr might be too simple. Alternatively, the land ice-based definition of interglacials needs revision if applied to the entire Quaternary. This study presents a new definition of interglacials during the Quaternary. The authors find the appearance of interglacials is in general following the 41-kyr cycle of obliquity with various exceptions, suggesting a more complex physical mechanism triggering glacial terminations.
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Affiliation(s)
- Peter Köhler
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung (AWI), P.O. Box 12 01 61, Bremerhaven, 27515, Germany.
| | - Roderik S W van de Wal
- Institute for Marine and Atmospheric Research Utrecht (IMAU) and Faculty of Geosciences, Department of Physical Geography, Utrecht University, Princetonplein 5, Utrecht, 3584 CC, The Netherlands
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25
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De Vleeschouwer D, Drury AJ, Vahlenkamp M, Rochholz F, Liebrand D, Pälike H. High-latitude biomes and rock weathering mediate climate-carbon cycle feedbacks on eccentricity timescales. Nat Commun 2020; 11:5013. [PMID: 33024102 PMCID: PMC7538577 DOI: 10.1038/s41467-020-18733-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 09/09/2020] [Indexed: 11/29/2022] Open
Abstract
The International Ocean Discovery Programme (IODP) and its predecessors generated a treasure trove of Cenozoic climate and carbon cycle dynamics. Yet, it remains unclear how climate and carbon cycle interacted under changing geologic boundary conditions. Here, we present the carbon isotope (δ13C) megasplice, documenting deep-ocean δ13C evolution since 35 million years ago (Ma). We juxtapose the δ13C megasplice with its δ18O counterpart and determine their phase-difference on ~100-kyr eccentricity timescales. This analysis reveals that 2.4-Myr eccentricity cycles modulate the δ13C-δ18O phase relationship throughout the Oligo-Miocene (34-6 Ma), potentially through changes in continental weathering. At 6 Ma, a striking switch from in-phase to anti-phase behaviour occurs, signalling a reorganization of the climate-carbon cycle system. We hypothesize that this transition is consistent with Arctic cooling: Prior to 6 Ma, low-latitude continental carbon reservoirs expanded during astronomically-forced cool spells. After 6 Ma, however, continental carbon reservoirs contract rather than expand during cold periods due to competing effects between Arctic biomes (ice, tundra, taiga). We conclude that, on geologic timescales, System Earth experienced state-dependent modes of climate–carbon cycle interaction. Climate and carbon cycle interactions during major Earth system changes through the Cenozoic remain unclear. Here, the authors present a combined δ13C-δ18O megasplice for the last 35 Ma which allows them to identify three marked intervals of distinct climate–carbon cycle interactions.
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Affiliation(s)
- David De Vleeschouwer
- MARUM - Center for Marine and Environmental Sciences, University of Bremen, Klagenfurterstraße 2-4, 28359, Bremen, Germany.
| | - Anna Joy Drury
- MARUM - Center for Marine and Environmental Sciences, University of Bremen, Klagenfurterstraße 2-4, 28359, Bremen, Germany.,Department of Earth Sciences, University College London, Gower Street, London, WC1E 6BT, UK
| | - Maximilian Vahlenkamp
- MARUM - Center for Marine and Environmental Sciences, University of Bremen, Klagenfurterstraße 2-4, 28359, Bremen, Germany
| | - Fiona Rochholz
- MARUM - Center for Marine and Environmental Sciences, University of Bremen, Klagenfurterstraße 2-4, 28359, Bremen, Germany.,Research Group for Earth Observation, Pädagogische Hochschule Heidelberg, Czernyring 22/10-12, 69120, Heidelberg, Germany
| | - Diederik Liebrand
- MARUM - Center for Marine and Environmental Sciences, University of Bremen, Klagenfurterstraße 2-4, 28359, Bremen, Germany
| | - Heiko Pälike
- MARUM - Center for Marine and Environmental Sciences, University of Bremen, Klagenfurterstraße 2-4, 28359, Bremen, Germany
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26
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Abstract
During the Eocene, high-latitude regions were much warmer than today and substantial polar ice sheets were lacking. Indeed, the initiation of significant polar ice sheets near the end of the Eocene has been closely linked to global cooling. Here, we examine the relationship between global temperatures and continental-scale polar ice sheets following the establishment of ice sheets on Antarctica ∼34 million years ago, using records of surface temperatures from around the world. We find that high-latitude temperatures were almost as warm after the initiation of Antarctic glaciation as before, challenging our basic understanding of how climate works, and of the development of climate and ice volume through time. Falling atmospheric CO2 levels led to cooling through the Eocene and the expansion of Antarctic ice sheets close to their modern size near the beginning of the Oligocene, a period of poorly documented climate. Here, we present a record of climate evolution across the entire Oligocene (33.9 to 23.0 Ma) based on TEX86 sea surface temperature (SST) estimates from southwestern Atlantic Deep Sea Drilling Project Site 516 (paleolatitude ∼36°S) and western equatorial Atlantic Ocean Drilling Project Site 929 (paleolatitude ∼0°), combined with a compilation of existing SST records and climate modeling. In this relatively low CO2 Oligocene world (∼300 to 700 ppm), warm climates similar to those of the late Eocene continued with only brief interruptions, while the Antarctic ice sheet waxed and waned. SSTs are spatially heterogenous, but generally support late Oligocene warming coincident with declining atmospheric CO2. This Oligocene warmth, especially at high latitudes, belies a simple relationship between climate and atmospheric CO2 and/or ocean gateways, and is only partially explained by current climate models. Although the dominant climate drivers of this enigmatic Oligocene world remain unclear, our results help fill a gap in understanding past Cenozoic climates and the way long-term climate sensitivity responded to varying background climate states.
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27
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Westerhold T, Marwan N, Drury AJ, Liebrand D, Agnini C, Anagnostou E, Barnet JSK, Bohaty SM, De Vleeschouwer D, Florindo F, Frederichs T, Hodell DA, Holbourn AE, Kroon D, Lauretano V, Littler K, Lourens LJ, Lyle M, Pälike H, Röhl U, Tian J, Wilkens RH, Wilson PA, Zachos JC. An astronomically dated record of Earth’s climate and its predictability over the last 66 million years. Science 2020; 369:1383-1387. [DOI: 10.1126/science.aba6853] [Citation(s) in RCA: 352] [Impact Index Per Article: 88.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 07/28/2020] [Indexed: 11/02/2022]
Abstract
Much of our understanding of Earth’s past climate comes from the measurement of oxygen and carbon isotope variations in deep-sea benthic foraminifera. Yet, long intervals in existing records lack the temporal resolution and age control needed to thoroughly categorize climate states of the Cenozoic era and to study their dynamics. Here, we present a new, highly resolved, astronomically dated, continuous composite of benthic foraminifer isotope records developed in our laboratories. Four climate states—Hothouse, Warmhouse, Coolhouse, Icehouse—are identified on the basis of their distinctive response to astronomical forcing depending on greenhouse gas concentrations and polar ice sheet volume. Statistical analysis of the nonlinear behavior encoded in our record reveals the key role that polar ice volume plays in the predictability of Cenozoic climate dynamics.
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Affiliation(s)
- Thomas Westerhold
- MARUM–Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| | - Norbert Marwan
- Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, 14412 Potsdam, Germany
- University of Potsdam, Institute of Geosciences, 14469 Potsdam, Germany
| | - Anna Joy Drury
- MARUM–Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Diederik Liebrand
- MARUM–Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| | - Claudia Agnini
- Dipartimento di Geoscienze, Università degli Studi di Padova, Via Gradenigo 6, I-35131 Padova, Italy
| | - Eleni Anagnostou
- GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany
| | - James S. K. Barnet
- Camborne School of Mines and Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, UK
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, Scotland, UK
| | - Steven M. Bohaty
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, UK
| | - David De Vleeschouwer
- MARUM–Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| | - Fabio Florindo
- Istituto Nazionale di Geofisica e Vulcanologia, INGV, Rome, Italy
- Institute for Climate Change Solutions, Pesaro e Urbino, Italy
| | - Thomas Frederichs
- MARUM–Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
- Faculty of Geosciences, University of Bremen, Bremen, Germany
| | - David A. Hodell
- Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - Ann E. Holbourn
- Institute of Geosciences, Christian-Albrechts-University, Kiel 24118, Germany
| | - Dick Kroon
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
| | | | - Kate Littler
- Camborne School of Mines and Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, UK
| | - Lucas J. Lourens
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Princetonlaan 8a, 3584 CB Utrecht, Netherlands
| | - Mitchell Lyle
- College of Earth, Ocean, and Atmospheric Science, Oregon State University, Corvallis, OR 97331, USA
| | - Heiko Pälike
- MARUM–Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| | - Ursula Röhl
- MARUM–Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| | - Jun Tian
- State Key Laboratory of Marine Geology, Tongji University, Siping Road 1239, Shanghai 200092, PR China
| | - Roy H. Wilkens
- School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, HI 96822, USA
| | - Paul A. Wilson
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, UK
| | - James C. Zachos
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, California, USA
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28
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Anagnostou E, John EH, Babila TL, Sexton PF, Ridgwell A, Lunt DJ, Pearson PN, Chalk TB, Pancost RD, Foster GL. Proxy evidence for state-dependence of climate sensitivity in the Eocene greenhouse. Nat Commun 2020; 11:4436. [PMID: 32895377 PMCID: PMC7477227 DOI: 10.1038/s41467-020-17887-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 07/22/2020] [Indexed: 11/08/2022] Open
Abstract
Despite recent advances, the link between the evolution of atmospheric CO2 and climate during the Eocene greenhouse remains uncertain. In particular, modelling studies suggest that in order to achieve the global warmth that characterised the early Eocene, warmer climates must be more sensitive to CO2 forcing than colder climates. Here, we test this assertion in the geological record by combining a new high-resolution boron isotope-based CO2 record with novel estimates of Global Mean Temperature. We find that Equilibrium Climate Sensitivity (ECS) was indeed higher during the warmest intervals of the Eocene, agreeing well with recent model simulations, and declined through the Eocene as global climate cooled. These observations indicate that the canonical IPCC range of ECS (1.5 to 4.5 °C per doubling) is unlikely to be appropriate for high-CO2 warm climates of the past, and the state dependency of ECS may play an increasingly important role in determining the state of future climate as the Earth continues to warm.
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Affiliation(s)
- E Anagnostou
- GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Wischhofstrasse 1-3, 24148, Kiel, Germany.
- School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus, Southampton, SO14 3ZH, UK.
| | - E H John
- School of Earth and Environmental Sciences, Cardiff University, Park Place, Cardiff, CF10 3AT, UK
| | - T L Babila
- School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus, Southampton, SO14 3ZH, UK
| | - P F Sexton
- School of Environment, Earth and Ecosystem Sciences, The Open University, Milton Keynes, MK7 6AA, UK
| | - A Ridgwell
- Department of Earth Sciences, University of California, Riverside, CA, 92521, USA
| | - D J Lunt
- School of Geographical Sciences, University of Bristol, University Rd, Bristol, BS8 1SS, UK
| | - P N Pearson
- School of Earth and Environmental Sciences, Cardiff University, Park Place, Cardiff, CF10 3AT, UK
| | - T B Chalk
- School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus, Southampton, SO14 3ZH, UK
| | - R D Pancost
- Organic Geochemistry Unit, School of Chemistry and School of Earth Sciences, Cabot Institute for the Environment, University of Bristol, Queens Rd, Bristol, BS8 1UJ, UK
| | - G L Foster
- School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus, Southampton, SO14 3ZH, UK
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29
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Testing algal-based pCO 2 proxies at a modern CO 2 seep (Vulcano, Italy). Sci Rep 2020; 10:10508. [PMID: 32601284 PMCID: PMC7324594 DOI: 10.1038/s41598-020-67483-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 06/02/2020] [Indexed: 12/03/2022] Open
Abstract
Understanding long-term trends in atmospheric concentrations of carbon dioxide (pCO2) has become increasingly relevant as modern concentrations surpass recent historic trends. One method for estimating past pCO2, the stable carbon isotopic fractionation associated with photosynthesis (Ɛp) has shown promise over the past several decades, in particular using species-specific biomarker lipids such as alkenones. Recently, the Ɛp of more general biomarker lipids, organic compounds derived from a multitude of species, have been applied to generate longer-spanning, more ubiquitous records than those of alkenones but the sensitivity of this proxy to changes in pCO2 has not been constrained in modern settings. Here, we test Ɛp using a variety of general biomarkers along a transect taken from a naturally occurring marine CO2 seep in Levante Bay of the Aeolian island of Vulcano in Italy. The studied general biomarkers, loliolide, cholesterol, and phytol, all show increasing depletion in 13C over the transect from the control site towards the seep, suggesting that CO2 exerts a strong control on isotopic fractionation in natural phytoplankton communities. The strongest shift in fractionation was seen in phytol, and pCO2 estimates derived from phytol confirm the utility of this biomarker as a proxy for pCO2 reconstruction.
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30
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Drag DW, Slattery R, Siebers M, DeLucia EH, Ort DR, Bernacchi CJ. Soybean photosynthetic and biomass responses to carbon dioxide concentrations ranging from pre-industrial to the distant future. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:3690-3700. [PMID: 32170296 PMCID: PMC7475242 DOI: 10.1093/jxb/eraa133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 03/09/2020] [Indexed: 05/29/2023]
Abstract
Increasing atmospheric carbon dioxide concentration ([CO2]) directly impacts C3 plant photosynthesis and productivity, and the rate at which [CO2] is increasing is greater than initially predicted by worst-case scenario climate models. Thus, it is increasingly important to assess the physiological responses of C3 plants, especially those that serve as important crops, to [CO2] beyond the mid-range levels used in traditional experiments. Here, we grew the C3 crop soybean (Glycine max) at eight different [CO2] levels spanning subambient (340 ppm) to the highest level thought plausible (~2000 ppm) in chambers for 5 weeks. Physiological development was delayed and plant height and total leaf area increased at [CO2] levels higher than ambient conditions, with very little difference in these parameters among the elevated [CO2] treatments >900 ppm. Daily photosynthesis initially increased with rising [CO2] but began to level off at ~1000 ppm CO2. Similar results occurred in biomass accumulation. Thus, as [CO2] continues to match or exceed the worst-case emission scenarios, these results indicate that carbon gain, growth, and potentially yield increases will diminish, thereby ultimately constraining the positive impact that continuing increases in atmospheric [CO2] could have on crop productivity and global terrestrial carbon sinks.
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Affiliation(s)
- David W Drag
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Rebecca Slattery
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Matthew Siebers
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Evan H DeLucia
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Institute for Sustainability, Energy, and Environment, University of Illinois at Urbana-Champaign, IL, USA
| | - Donald R Ort
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Carl J Bernacchi
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Institute for Sustainability, Energy, and Environment, University of Illinois at Urbana-Champaign, IL, USA
- Global Change and Photosynthesis Research Unit, United States Department of Agriculture, Agricultural Research Service, Urbana, IL, USA
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31
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Abstract
C4 photosynthesis evolved multiple times independently from ancestral C3 photosynthesis in a broad range of flowering land plant families and in both monocots and dicots. The evolution of C4 photosynthesis entails the recruitment of enzyme activities that are not involved in photosynthetic carbon fixation in C3 plants to photosynthesis. This requires a different regulation of gene expression as well as a different regulation of enzyme activities in comparison to the C3 context. Further, C4 photosynthesis relies on a distinct leaf anatomy that differs from that of C3, requiring a differential regulation of leaf development in C4. We summarize recent progress in the understanding of C4-specific features in evolution and metabolic regulation in the context of C4 photosynthesis.
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Affiliation(s)
- Urte Schlüter
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany; ,
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany; ,
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32
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Dumont M, Pichevin L, Geibert W, Crosta X, Michel E, Moreton S, Dobby K, Ganeshram R. The nature of deep overturning and reconfigurations of the silicon cycle across the last deglaciation. Nat Commun 2020; 11:1534. [PMID: 32210225 PMCID: PMC7093442 DOI: 10.1038/s41467-020-15101-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 02/14/2020] [Indexed: 12/02/2022] Open
Abstract
Changes in ocean circulation and the biological carbon pump have been implicated as the drivers behind the rise in atmospheric CO2 across the last deglaciation; however, the processes involved remain uncertain. Previous records have hinted at a partitioning of deep ocean ventilation across the two major intervals of atmospheric CO2 rise, but the consequences of differential ventilation on the Si cycle has not been explored. Here we present three new records of silicon isotopes in diatoms and sponges from the Southern Ocean that together show increased Si supply from deep mixing during the deglaciation with a maximum during the Younger Dryas (YD). We suggest Antarctic sea ice and Atlantic overturning conditions favoured abyssal ocean ventilation at the YD and marked an interval of Si cycle reorganisation. By regulating the strength of the biological pump, the glacial-interglacial shift in the Si cycle may present an important control on Pleistocene CO2 concentrations.
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Affiliation(s)
- M Dumont
- School of Geosciences, University of Edinburgh, Edinburgh, UK.
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK.
| | - L Pichevin
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - W Geibert
- Alfred Wegener Institute, Bremerhaven, Germany
| | - X Crosta
- UMR 5805 EPOC, Universite de Bordeaux, Bordeaux, France
| | - E Michel
- Laboratoire des Sciences du Climat et l'Environnement/Institute Pierre-Simon Laplace, Laboratoire CNRS-CEA-UVSQ, Gif-sur-Yvette, France
| | - S Moreton
- Scottish Universities Environmental Research Centre, East Kilbride, UK
| | - K Dobby
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - R Ganeshram
- School of Geosciences, University of Edinburgh, Edinburgh, UK
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33
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Hassanin A, Bonillo C, Tshikung D, Pongombo Shongo C, Pourrut X, Kadjo B, Nakouné E, Tu VT, Prié V, Goodman SM. Phylogeny of African fruit bats (Chiroptera, Pteropodidae) based on complete mitochondrial genomes. J ZOOL SYST EVOL RES 2020. [DOI: 10.1111/jzs.12373] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Alexandre Hassanin
- Institut Systématique Evolution Biodiversité (ISYEB) Sorbonne Université MNHN CNRS EPHE Paris France
| | - Céline Bonillo
- Muséum National d'Histoire NaturelleUMS 2700 2AD Paris France
| | - Didier Tshikung
- Faculté de Médecine Vétérinaire Université de Lubumbashi Lubumbashi Democratic Republic of the Congo
| | - Célestin Pongombo Shongo
- Faculté de Médecine Vétérinaire Université de Lubumbashi Lubumbashi Democratic Republic of the Congo
| | - Xavier Pourrut
- Institut de Recherche pour le Développement UR 224 MIVEGEC Marseille France
| | - Blaise Kadjo
- UFR Biosciences Université Félix Houphouet‐Boigny Abidjan Côte d'Ivoire
| | | | - Vuong Tan Tu
- Institute of Ecology and Biological Resources Vietnam Academy of Science and Technology Hanoi Vietnam
| | - Vincent Prié
- Institut Systématique Evolution Biodiversité (ISYEB) Sorbonne Université MNHN CNRS EPHE Paris France
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34
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Sage RF. Global change biology: A primer. GLOBAL CHANGE BIOLOGY 2020; 26:3-30. [PMID: 31663217 DOI: 10.1111/gcb.14893] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 09/09/2019] [Indexed: 05/17/2023]
Abstract
Because of human action, the Earth has entered an era where profound changes in the global environment are creating novel conditions that will be discernable far into the future. One consequence may be a large reduction of the Earth's biodiversity, potentially representing a sixth mass extinction. With effective stewardship, the global change drivers that threaten the Earth's biota could be alleviated, but this requires clear understanding of the drivers, their interactions, and how they impact ecological communities. This review identifies 10 anthropogenic global change drivers and discusses how six of the drivers (atmospheric CO2 enrichment, climate change, land transformation, species exploitation, exotic species invasions, eutrophication) impact Earth's biodiversity. Driver impacts on a particular species could be positive or negative. In either case, they initiate secondary responses that cascade along ecological lines of connection and in doing so magnify the initial impact. The unique nature of the threat to the Earth's biodiversity is not simply due to the magnitude of each driver, but due to the speed of change, the novelty of the drivers, and their interactions. Emphasizing one driver, notably climate change, is problematic because the other global change drivers also degrade biodiversity and together threaten the stability of the biosphere. As the main academic journal addressing global change effects on living systems, GCB is well positioned to provide leadership in solving the global change challenge. If humanity cannot meet the challenge, then GCB is positioned to serve as a leading chronicle of the sixth mass extinction to occur on planet Earth.
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Affiliation(s)
- Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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35
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Abstract
Quantifying ancient atmospheric pCO2 provides valuable insights into the interplay between greenhouse gases and global climate. Beyond the 800-ky history uncovered by ice cores, discrepancies in both the trend and magnitude of pCO2 changes remain among different proxy-derived results. The traditional paleosol pCO2 paleobarometer suffers from largely unconstrained soil-respired CO2 concentration (S(z)). Using finely disseminated carbonates precipitated in paleosols from the Chinese Loess Plateau, here we identified that their S(z) can be quantitatively constrained by soil magnetic susceptibility. Based on this approach, we reconstructed pCO2 during 2.6–0.9 Ma, which documents overall low pCO2 levels (<300 ppm) comparable with ice core records, indicating that the Earth system has operated under late Pleistocene pCO2 levels for an extended period. The pCO2 levels do not show statistically significant differences across the mid-Pleistocene Transition (ca. 1.2–0.8 Ma), suggesting that CO2 is probably not the driver of this important climate change event. Climate dynamics in Earth’s distant history can provide important forecasting for future changes, but uncertainties in proxy-derived carbon dioxide results are common. Here Da and colleagues present a refined paleosol proxy for carbon dioxide reconstruction, and report persistently low levels ( < 300 ppm) throughout the Pleistocene interglacials.
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36
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Stein RA, Sheldon ND, Smith S. Rapid response to anthropogenic climate change by Thuja occidentalis: implications for past climate reconstructions and future climate predictions. PeerJ 2019; 7:e7378. [PMID: 31388476 PMCID: PMC6662565 DOI: 10.7717/peerj.7378] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/29/2019] [Indexed: 11/24/2022] Open
Abstract
Carbon isotope values of leaves (δ13Cleaf) from meta-analyses and growth chamber studies of C3 plants have been used to propose generalized relationships between δ13Cleaf and climate variables such as mean annual precipitation (MAP), atmospheric concentration of carbon dioxide ([CO2]), and other climate variables. These generalized relationships are frequently applied to the fossil record to create paleoclimate reconstructions. Although plant evolution influences biochemistry and response to environmental stress, few studies have assessed species-specific carbon assimilation as it relates to climate outside of a laboratory. We measured δ13Cleaf values and C:N ratios of a wide-ranging evergreen conifer with a long fossil record, Thuja occidentalis (Cupressaceae) collected 1804-2017, in order to maximize potential paleo-applications of our focal species. This high-resolution record represents a natural experiment from pre-Industrial to Industrial times, which spans a range of geologically meaningful [CO2] and δ13Catm values. Δleaf values (carbon isotope discrimination between δ13Catm and δ13Cleaf) remain constant across climate conditions, indicating limited response to environmental stress. Only δ13Cleaf and δ13Catm values showed a strong relationship (linear), thus, δ13Cleaf is an excellent record of carbon isotopic changes in the atmosphere during Industrialization. In contrast with previous free-air concentration enrichment experiments, no relationship was found between C:N ratios and increasing [CO2]. Simultaneously static C:N ratios and Δleaf in light of increasing CO2 highlights plants' inability to match rapid climate change with increased carbon assimilation as previously expected; Δleaf values are not reliable tools to reconstruct MAP and [CO2], and δ13Cleaf values only decrease with [CO2] in line with atmospheric carbon isotope changes.
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Affiliation(s)
- Rebekah A. Stein
- Department of Earth and Environmental Sciences, University of Michigan–Ann Arbor, Ann Arbor, MI, USA
| | - Nathan D. Sheldon
- Department of Earth and Environmental Sciences, University of Michigan–Ann Arbor, Ann Arbor, MI, USA
| | - Selena Smith
- Department of Earth and Environmental Sciences, University of Michigan–Ann Arbor, Ann Arbor, MI, USA
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37
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Neogene cooling driven by land surface reactivity rather than increased weathering fluxes. Nature 2019; 571:99-102. [DOI: 10.1038/s41586-019-1332-y] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 04/26/2019] [Indexed: 11/09/2022]
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38
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van Velzen R, Doyle JJ, Geurts R. A Resurrected Scenario: Single Gain and Massive Loss of Nitrogen-Fixing Nodulation. TRENDS IN PLANT SCIENCE 2019; 24:49-57. [PMID: 30409687 DOI: 10.1016/j.tplants.2018.10.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 09/28/2018] [Accepted: 10/12/2018] [Indexed: 05/26/2023]
Abstract
Root nodule endosymbiosis with nitrogen-fixing bacteria provides plants with unlimited access to fixed nitrogen, but at a significant energetic cost. Nodulation is generally considered to have originated in parallel in different lineages, but this hypothesis downplays the genetic complexity of nodulation and requires independent recruitment of many common features across lineages. Recent phylogenomic studies revealed that genes that function in establishing or maintaining nitrogen-fixing nodules are independently lost in non-nodulating relatives of nitrogen-fixing plants. In our opinion, these data are best explained by a scenario of a single gain followed by massively parallel loss of nitrogen-fixing root nodules triggered by events at geological scale.
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Affiliation(s)
- Robin van Velzen
- Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University & Research, 6708PB, Wageningen, The Netherlands
| | - Jeff J Doyle
- School of Integrative Plant Science, Section of Plant Breeding & Genetics and Section of Plant Biology, 240 Emerson Hall, Cornell University, Ithaca, NY 14853, USA
| | - Rene Geurts
- Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University & Research, 6708PB, Wageningen, The Netherlands.
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39
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Prazeres M, Renema W. Evolutionary significance of the microbial assemblages of large benthic Foraminifera. Biol Rev Camb Philos Soc 2018; 94:828-848. [PMID: 30450723 PMCID: PMC7379505 DOI: 10.1111/brv.12482] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 10/21/2018] [Accepted: 10/24/2018] [Indexed: 12/24/2022]
Abstract
Large benthic Foraminifera (LBF) are major carbonate producers on coral reefs, and are hosts to a diverse symbiotic microbial community. During warm episodes in the geological past, these reef-building organisms expanded their geographical ranges as subtropical and tropical belts moved into higher latitudes. During these range-expansion periods, LBF were the most prolific carbonate producers on reefs, dominating shallow carbonate platforms over reef-building corals. Even though the fossil and modern distributions of groups of species that harbour different types of symbionts are known, the nature, mechanisms, and factors that influence their occurrence remain elusive. Furthermore, the presence of a diverse and persistent bacterial community has only recently gained attention. We examined recent advances in molecular identification of prokaryotic (i.e. bacteria) and eukaryotic (i.e. microalgae) associates, and palaeoecology, and place the partnership with bacteria and algae in the context of climate change. In critically reviewing the available fossil and modern data on symbiosis, we reveal a crucial role of microalgae in the response of LBF to ocean warming, and their capacity to colonise a variety of habitats, across both latitudes and broad depth ranges. Symbiont identity is a key factor enabling LBF to expand their geographic ranges when the sea-surface temperature increases. Our analyses showed that over the past 66 million years (My), diatom-bearing species were dominant in reef environments. The modern record shows that these species display a stable, persistent eukaryotic assemblage across their geographic distribution range, and are less dependent on symbiotic photosynthesis for survival. By contrast, dinoflagellate and chlorophytic species, which show a provincial distribution, tend to have a more flexible eukaryotic community throughout their range. This group is more dependent on their symbionts, and flexibility in their symbiosis is likely to be the driving force behind their evolutionary history, as they form a monophyletic group originating from a rhodophyte-bearing ancestor. The study of bacterial assemblages, while still in its infancy, is a promising field of study. Bacterial communities are likely to be shaped by the local environment, although a core bacterial microbiome is found in species with global distributions. Cryptic speciation is also an important factor that must be taken into consideration. As global warming intensifies, genetic divergence in hosts in addition to the range of flexibility/specificity within host-symbiont associations will be important elements in the continued evolutionary success of LBF species in a wide range of environments. Based on fossil and modern data, we conclude that the microbiome, which includes both algal and bacterial partners, is a key factor influencing the evolution of LBF. As a result, the microbiome assists LBF in colonising a wide range of habitats, and allowed them to become the most important calcifiers on shallow platforms worldwide during periods of ocean warming in the geologic past. Since LBF are crucial ecosystem engineers and prolific carbonate producers, the microbiome is a critical component that will play a central role in the responses of LBF to a changing ocean, and ultimately in shaping the future of coral reefs.
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Affiliation(s)
- Martina Prazeres
- Marine Biodiversity Group, Naturalis Biodiversity Center, 2300 RA, Leiden, 9517, the Netherlands
| | - Willem Renema
- Marine Biodiversity Group, Naturalis Biodiversity Center, 2300 RA, Leiden, 9517, the Netherlands
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40
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Dyez KA, Hönisch B, Schmidt GA. Early Pleistocene obliquity-scale pCO 2 variability at ~1.5 million years ago. PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY 2018; 33:1270-1291. [PMID: 32715282 PMCID: PMC7380090 DOI: 10.1029/2018pa003349] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 10/31/2018] [Indexed: 05/12/2023]
Abstract
In the early Pleistocene, global temperature cycles predominantly varied with ~41-kyr (obliquity-scale) periodicity. Atmospheric greenhouse gas concentrations likely played a role in these climate cycles; marine sediments provide an indirect geochemical means to estimate early Pleistocene CO2. Here we present a boron isotope-based record of continuous high-resolution surface ocean pH and inferred atmospheric CO2 changes. Our results show that, within a window of time in the early Pleistocene (1.38-1.54 Ma), pCO2 varied with obliquity, confirming that, analogous to late Pleistocene conditions, the carbon cycle and climate covaried at ~1.5 Ma. Pairing the reconstructed early Pleistocene pCO2 amplitude (92 ±13 μatm) with a comparably smaller global surface temperature glacial/interglacial amplitude (3.0 ±0.5 K), yields a surface temperature change to CO2 radiative forcing ratio of S [CO2]~0.75 (± 0.5) °C/Wm-2, as compared to the late Pleistocene S [CO2] value of ~1.75 (± 0.6) °C/Wm-2. This direct comparison of pCO2 and temperature implicitly incorporates the large ice sheet forcing as an internal feedback and is not directly applicable to future warming. We evaluate this result with a simple climate model, and show that the presumably thinner, though extensive, northern hemisphere ice sheets would increase surface temperature sensitivity to radiative forcing. Thus, the mechanism to dampen actual temperature variability in the early Pleistocene more likely lies with Southern Ocean circulation dynamics or antiphase hemispheric forcing. We also compile this new carbon dioxide record with published Plio-Pleistocene δ11B records using consistent boundary conditions and explore potential reasons for the discrepancy between Pliocene pCO2 based on different planktic foraminifera.
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Affiliation(s)
- Kelsey A. Dyez
- Lamont-Doherty Earth Observatory, Columbia University, New York, NY, USA
- Now at Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Bärbel Hönisch
- Lamont-Doherty Earth Observatory, Columbia University, New York, NY, USA
- Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA
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41
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Londoño L, Royer DL, Jaramillo C, Escobar J, Foster DA, Cárdenas-Rozo AL, Wood A. Early Miocene CO 2 estimates from a Neotropical fossil leaf assemblage exceed 400 ppm. AMERICAN JOURNAL OF BOTANY 2018; 105:1929-1937. [PMID: 30418663 DOI: 10.1002/ajb2.1187] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/20/2018] [Indexed: 06/09/2023]
Abstract
PREMISE OF THE STUDY The global climate during the early Miocene was warmer than the present and preceded the even warmer middle Miocene climatic optimum. The paleo-CO2 records for this interval suggest paradoxically low concentrations (<450 ppm) that are difficult to reconcile with a warmer-than-present global climate. METHODS In this study, we use a leaf gas-exchange model to estimate CO2 concentrations using stomatal characteristics of fossil leaves from a late early Miocene Neotropical assemblage from Panama that we date to 18.01 ± 0.17 Ma via 238 U/206 Pb zircon geochronology. We first validated the model for Neotropical environments by estimating CO2 from canopy leaves of 21 extant species in a natural Panamanian forest and from leaves of seven Neotropical species in greenhouse experiments at 400 and 700 ppm. KEY RESULTS The results showed that the most probable combined CO2 estimate from the natural forests and 400 ppm experiments is 475 ppm, and for the 700 ppm experiments is 665 ppm. CO2 estimates from the five fossil species exhibit bimodality, with two species most consistent with a low mode (528 ppm) and three with a high mode (912 ppm). CONCLUSIONS Despite uncertainties, it is very likely (at >95% confidence) that CO2 during the late early Miocene exceeded 400 ppm. These results revise upwards the likely CO2 concentration at this time, more in keeping with a CO2 -forced greenhouse climate.
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Affiliation(s)
- Liliana Londoño
- Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá
- Departamento de Ciencias Ecológicas, Universidad de Chile, Santiago, Chile
| | - Dana L Royer
- Department of Earth and Environmental Sciences, Wesleyan University, Middletown, Connecticut, 06459, USA
| | - Carlos Jaramillo
- Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá
| | - Jaime Escobar
- Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá
- Departamento de Ingeniería Civil y Ambiental, Universidad del Norte, Barranquilla, Colombia
| | - David A Foster
- Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, Florida, 32611, USA
| | | | - Aaron Wood
- Department of Geological & Atmospheric Sciences, Iowa State University, Ames, Iowa, USA
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42
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Song B, Chen S, Chen W. Dinoflagellates, a Unique Lineage for Retrogene Research. Front Microbiol 2018; 9:1556. [PMID: 30050525 PMCID: PMC6050394 DOI: 10.3389/fmicb.2018.01556] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/22/2018] [Indexed: 12/14/2022] Open
Abstract
The birth and evolution of retrogenes have played crucial roles in genome evolution. Dinoflagellates represent a unique lineage for retrogene research because the retrogenes can be reliably identified by the presence of a 22 nucleotide splice leader called DinoSL, which is post-transcriptionally added to the 5' terminus of all mRNAs. Compared to studies of retrogenes conducted in other model genomes, dinoflagellate retrogenes can potentially be more comprehensively characterized because intron-containing retrogenes have already been detected. Unfortunately, dinoflagellate retrogene research has long been neglected. Here, we review the work on dinoflagellate retrogenes and show their distinct character. Like the dinoflagellate genome itself, dinoflagellate retrogenes are also characterized by many unusual features, including a high survival rate and large numbers in the genome. These data are critical complements to what we know about retrogenes, and will further frame our understanding of retroposition and its roles in genome evolution, as well as providing new insights into retrogene studies in other genomes.
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Affiliation(s)
- Bo Song
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.,Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, China
| | - Sijie Chen
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Wenbin Chen
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
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43
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Cramwinckel MJ, Huber M, Kocken IJ, Agnini C, Bijl PK, Bohaty SM, Frieling J, Goldner A, Hilgen FJ, Kip EL, Peterse F, van der Ploeg R, Röhl U, Schouten S, Sluijs A. Synchronous tropical and polar temperature evolution in the Eocene. Nature 2018; 559:382-386. [PMID: 29967546 DOI: 10.1038/s41586-018-0272-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 04/13/2018] [Indexed: 11/09/2022]
Abstract
Palaeoclimate reconstructions of periods with warm climates and high atmospheric CO2 concentrations are crucial for developing better projections of future climate change. Deep-ocean1,2 and high-latitude3 palaeotemperature proxies demonstrate that the Eocene epoch (56 to 34 million years ago) encompasses the warmest interval of the past 66 million years, followed by cooling towards the eventual establishment of ice caps on Antarctica. Eocene polar warmth is well established, so the main obstacle in quantifying the evolution of key climate parameters, such as global average temperature change and its polar amplification, is the lack of continuous high-quality tropical temperature reconstructions. Here we present a continuous Eocene equatorial sea surface temperature record, based on biomarker palaeothermometry applied on Atlantic Ocean sediments. We combine this record with the sparse existing data4-6 to construct a 26-million-year multi-proxy, multi-site stack of Eocene tropical climate evolution. We find that tropical and deep-ocean temperatures changed in parallel, under the influence of both long-term climate trends and short-lived events. This is consistent with the hypothesis that greenhouse gas forcing7,8, rather than changes in ocean circulation9,10, was the main driver of Eocene climate. Moreover, we observe a strong linear relationship between tropical and deep-ocean temperatures, which implies a constant polar amplification factor throughout the generally ice-free Eocene. Quantitative comparison with fully coupled climate model simulations indicates that global average temperatures were about 29, 26, 23 and 19 degrees Celsius in the early, early middle, late middle and late Eocene, respectively, compared to the preindustrial temperature of 14.4 degrees Celsius. Finally, combining proxy- and model-based temperature estimates with available CO2 reconstructions8 yields estimates of an Eocene Earth system sensitivity of 0.9 to 2.3 kelvin per watt per square metre at 68 per cent probability, consistent with the high end of previous estimates11.
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Affiliation(s)
- Margot J Cramwinckel
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands.
| | - Matthew Huber
- Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA
| | - Ilja J Kocken
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Claudia Agnini
- Department of Geosciences, University of Padova, Padova, Italy
| | - Peter K Bijl
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Steven M Bohaty
- Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, UK
| | - Joost Frieling
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Aaron Goldner
- Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA
| | - Frederik J Hilgen
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Elizabeth L Kip
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Francien Peterse
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Robin van der Ploeg
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Ursula Röhl
- MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Stefan Schouten
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands.,NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry and Utrecht University, Den Burg, The Netherlands
| | - Appy Sluijs
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
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44
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Some like it hot: the physiological ecology of C 4 plant evolution. Oecologia 2018; 187:941-966. [PMID: 29955992 DOI: 10.1007/s00442-018-4191-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 06/05/2018] [Indexed: 10/28/2022]
Abstract
The evolution of C4 photosynthesis requires an intermediate phase where photorespiratory glycine produced in the mesophyll cells must flow to the vascular sheath cells for metabolism by glycine decarboxylase. This glycine flux concentrates photorespired CO2 within the sheath cells, allowing it to be efficiently refixed by sheath Rubisco. A modest C4 biochemical cycle is then upregulated, possibly to support the refixation of photorespired ammonia in sheath cells, with subsequent increases in C4 metabolism providing incremental benefits until an optimized C4 pathway is established. 'Why' C4 photosynthesis evolved is largely explained by ancestral C3 species exploiting photorespiratory CO2 to improve carbon gain and thus enhance fitness. While photorespiration depresses C3 performance, it produces a resource (photorespired CO2) that can be exploited to build an evolutionary bridge to C4 photosynthesis. 'Where' C4 evolved is indicated by the habitat of species branching near C3-to-C4 transitions on phylogenetic trees. Consistent with the photorespiratory bridge hypothesis, transitional species show that the large majority of > 60 C4 lineages arose in hot, dry, and/or saline regions where photorespiratory potential is high. 'When' C4 evolved has been clarified by molecular clock analyses using phylogenetic data, coupled with isotopic signatures from fossils. Nearly all C4 lineages arose after 25 Ma when atmospheric CO2 levels had fallen to near current values. This reduction in CO2, coupled with persistent high temperature at low-to-mid-latitudes, met a precondition where photorespiration was elevated, thus facilitating the evolutionary selection pressure that led to C4 photosynthesis.
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45
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Valenzuela JJ, López García de Lomana A, Lee A, Armbrust EV, Orellana MV, Baliga NS. Ocean acidification conditions increase resilience of marine diatoms. Nat Commun 2018; 9:2328. [PMID: 29899534 PMCID: PMC5997998 DOI: 10.1038/s41467-018-04742-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 05/21/2018] [Indexed: 11/25/2022] Open
Abstract
The fate of diatoms in future acidified oceans could have dramatic implications on marine ecosystems, because they account for ~40% of marine primary production. Here, we quantify resilience of Thalassiosira pseudonana in mid-20th century (300 ppm CO2) and future (1000 ppm CO2) conditions that cause ocean acidification, using a stress test that probes its ability to recover from incrementally higher amount of low-dose ultraviolet A (UVA) and B (UVB) radiation and re-initiate growth in day-night cycles, limited by nitrogen. While all cultures eventually collapse, those growing at 300 ppm CO2 succumb sooner. The underlying mechanism for collapse appears to be a system failure resulting from "loss of relational resilience," that is, inability to adopt physiological states matched to N-availability and phase of the diurnal cycle. Importantly, under elevated CO2 conditions diatoms sustain relational resilience over a longer timeframe, demonstrating increased resilience to future acidified ocean conditions. This stress test framework can be extended to evaluate and predict how various climate change associated stressors may impact microbial community resilience.
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Affiliation(s)
| | | | - Allison Lee
- Institute for Systems Biology, Seattle, WA, 98109, USA
| | - E V Armbrust
- School of Oceanography, University of Washington, Seattle, WA, 98105, USA
| | - Mónica V Orellana
- Institute for Systems Biology, Seattle, WA, 98109, USA.
- Applied Physics Laboratory, Polar Science Center, University of Washington, Seattle, WA, 98105, USA.
| | - Nitin S Baliga
- Institute for Systems Biology, Seattle, WA, 98109, USA.
- Departments of Biology and Microbiology, University of Washington, Seattle, WA, 98195, USA.
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, 98195, USA.
- Lawrence Berkeley National Lab, Berkeley, CA, 94720, USA.
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46
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Holbourn AE, Kuhnt W, Clemens SC, Kochhann KGD, Jöhnck J, Lübbers J, Andersen N. Late Miocene climate cooling and intensification of southeast Asian winter monsoon. Nat Commun 2018; 9:1584. [PMID: 29679005 PMCID: PMC5910391 DOI: 10.1038/s41467-018-03950-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 03/23/2018] [Indexed: 11/09/2022] Open
Abstract
The late Miocene offers the opportunity to assess the sensitivity of the Earth's climate to orbital forcing and to changing boundary conditions, such as ice volume and greenhouse gas concentrations, on a warmer-than-modern Earth. Here we investigate the relationships between low- and high-latitude climate variability in an extended succession from the subtropical northwestern Pacific Ocean. Our high-resolution benthic isotope record in combination with paired mixed layer isotope and Mg/Ca-derived temperature data reveal that a long-term cooling trend was synchronous with intensification of the Asian winter monsoon and strengthening of the biological pump from ~7 Ma until ~5.5 Ma. The climate shift occurred at the end of a global δ13C decrease, suggesting that changes in the carbon cycle involving the terrestrial and deep ocean carbon reservoirs were instrumental in driving late Miocene climate cooling. The inception of cooler climate conditions culminated with ephemeral Northern Hemisphere glaciations between 6.0 and 5.5 Ma.
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Affiliation(s)
- Ann E Holbourn
- Institute of Geosciences, Christian-Albrechts-University, Kiel, D-24118, Germany.
| | - Wolfgang Kuhnt
- Institute of Geosciences, Christian-Albrechts-University, Kiel, D-24118, Germany
| | - Steven C Clemens
- Earth, Environmental and Planetary Sciences, Brown University, Box 1846, Providence, RI, 02912, USA
| | - Karlos G D Kochhann
- Institute of Geosciences, Christian-Albrechts-University, Kiel, D-24118, Germany.,Technological Institute of Micropaleontology, Unisinos University, São Leopoldo, 93022-750, Brazil
| | - Janika Jöhnck
- Institute of Geosciences, Christian-Albrechts-University, Kiel, D-24118, Germany
| | - Julia Lübbers
- Institute of Geosciences, Christian-Albrechts-University, Kiel, D-24118, Germany
| | - Nils Andersen
- Leibniz Laboratory for Radiometric Dating and Stable Isotope Research, Christian-Albrechts-University, Kiel, D-24118, Germany
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47
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Huang S, Eronen JT, Janis CM, Saarinen JJ, Silvestro D, Fritz SA. Mammal body size evolution in North America and Europe over 20 Myr: similar trends generated by different processes. Proc Biol Sci 2018; 284:rspb.2016.2361. [PMID: 28202809 DOI: 10.1098/rspb.2016.2361] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/25/2017] [Indexed: 11/12/2022] Open
Abstract
Because body size interacts with many fundamental biological properties of a species, body size evolution can be an essential component of the generation and maintenance of biodiversity. Here we investigate how body size evolution can be linked to the clade-specific diversification dynamics in different geographical regions. We analyse an extensive body size dataset of Neogene large herbivores (covering approx. 50% of the 970 species in the orders Artiodactyla and Perissodactyla) in Europe and North America in a Bayesian framework. We reconstruct the temporal patterns of body size in each order on each continent independently, and find significant increases of minimum size in three of the continental assemblages (except European perissodactyls), suggesting an active selection for larger bodies. Assessment of trait-correlated birth-death models indicates that the common trend of body size increase is generated by different processes in different clades and regions. Larger-bodied artiodactyl species on both continents tend to have higher origination rates, and both clades in North America show strong links between large bodies and low extinction rate. Collectively, our results suggest a strong role of species selection and perhaps of higher-taxon sorting in driving body size evolution, and highlight the value of investigating evolutionary processes in a biogeographic context.
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Affiliation(s)
- Shan Huang
- Senckenberg Biodiversity and Climate Research Centre (BiK-F), Frankfurt am Main, Germany
| | - Jussi T Eronen
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.,BIOS Research Unit, Helsinki, Finland
| | - Christine M Janis
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
| | - Juha J Saarinen
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.,Natural History Museum, London, UK
| | - Daniele Silvestro
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Susanne A Fritz
- Senckenberg Biodiversity and Climate Research Centre (BiK-F), Frankfurt am Main, Germany.,Institute of Ecology, Evolution and Diversity, Goethe University, Frankfurt am Main, Germany
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48
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Verstraete B, Janssens S, Rønsted N. Non-nodulated bacterial leaf symbiosis promotes the evolutionary success of its host plants in the coffee family (Rubiaceae). Mol Phylogenet Evol 2017; 113:161-168. [PMID: 28552505 DOI: 10.1016/j.ympev.2017.05.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/23/2017] [Accepted: 05/23/2017] [Indexed: 11/15/2022]
Affiliation(s)
- Brecht Verstraete
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, 1307 Copenhagen, Denmark.
| | | | - Nina Rønsted
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, 1307 Copenhagen, Denmark.
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49
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Abstract
Modern mangroves are among the most carbon-rich biomes on Earth, but their long-term (≥106 years) impact on the global carbon cycle is unknown. The extent, productivity and preservation of mangroves are controlled by the interplay of tectonics, global sea level and sedimentation, including tide, wave and fluvial processes. The impact of these processes on mangrove-bearing successions in the Oligo-Miocene of the South China Sea (SCS) is evaluated herein. Palaeogeographic reconstructions, palaeotidal modelling and facies analysis suggest that elevated tidal range and bed shear stress optimized mangrove development along tide-influenced tropical coastlines. Preservation of mangrove organic carbon (OC) was promoted by high tectonic subsidence and fluvial sediment supply. Lithospheric storage of OC in peripheral SCS basins potentially exceeded 4,000 Gt (equivalent to 2,000 p.p.m. of atmospheric CO2). These results highlight the crucial impact of tectonic and oceanographic processes on mangrove OC sequestration within the global carbon cycle on geological timescales.
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50
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Groeneveld J, Henderiks J, Renema W, McHugh CM, De Vleeschouwer D, Christensen BA, Fulthorpe CS, Reuning L, Gallagher SJ, Bogus K, Auer G, Ishiwa T. Australian shelf sediments reveal shifts in Miocene Southern Hemisphere westerlies. SCIENCE ADVANCES 2017; 3:e1602567. [PMID: 28508066 PMCID: PMC5425240 DOI: 10.1126/sciadv.1602567] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 03/09/2017] [Indexed: 05/10/2023]
Abstract
Global climate underwent a major reorganization when the Antarctic ice sheet expanded ~14 million years ago (Ma) (1). This event affected global atmospheric circulation, including the strength and position of the westerlies and the Intertropical Convergence Zone (ITCZ), and, therefore, precipitation patterns (2-5). We present new shallow-marine sediment records from the continental shelf of Australia (International Ocean Discovery Program Sites U1459 and U1464) providing the first empirical evidence linking high-latitude cooling around Antarctica to climate change in the (sub)tropics during the Miocene. We show that Western Australia was arid during most of the Middle Miocene. Southwest Australia became wetter during the Late Miocene, creating a climate gradient with the arid interior, whereas northwest Australia remained arid throughout. Precipitation and river runoff in southwest Australia gradually increased from 12 to 8 Ma, which we relate to a northward migration or intensification of the westerlies possibly due to increased sea ice in the Southern Ocean (5). Abrupt aridification indicates that the westerlies shifted back to a position south of Australia after 8 Ma. Our midlatitude Southern Hemisphere data are consistent with the inference that expansion of sea ice around Antarctica resulted in a northward movement of the westerlies. In turn, this may have pushed tropical atmospheric circulation and the ITCZ northward, shifting the main precipitation belt over large parts of Southeast Asia (4).
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Affiliation(s)
- Jeroen Groeneveld
- MARUM–Center for Marine and Environmental Sciences, Department of Geosciences, University of Bremen, 28359 Bremen, Germany
- Corresponding author.
| | - Jorijntje Henderiks
- Department of Earth Sciences, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden
| | - Willem Renema
- Naturalis Biodiversity Center, PO Box 9517, 2300 RA Leiden, Netherlands
| | - Cecilia M. McHugh
- School of Earth and Environmental Sciences, Queens College (City University of New York), 65-30 Kissena Boulevard, Flushing, NY 11367, USA
| | - David De Vleeschouwer
- MARUM–Center for Marine and Environmental Sciences, Department of Geosciences, University of Bremen, 28359 Bremen, Germany
| | - Beth A. Christensen
- Environmental Studies, Adelphi University, 1 South Avenue SCB 201, Garden City, NY 11530, USA
| | - Craig S. Fulthorpe
- Institute for Geophysics, University of Texas at Austin, 10100 Burnet Road (R2200), Austin, TX 78758–4445, USA
| | - Lars Reuning
- Energy and Mineral Resources Group (EMR), Geological Institute Rheinisch-Westfälische Technische Hochschule (RWTH), Aachen University, Wuellnerstrasse, Aachen 52056, Germany
| | - Stephen J. Gallagher
- School of Earth Sciences, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Kara Bogus
- International Ocean Discovery Program, Texas A&M University, 1000 Discovery Drive, College Station, TX 77845–9547, USA
| | - Gerald Auer
- Institute of Earth Sciences, University of Graz, Heinrichstrasse 26, Graz 8010, Austria
| | - Takeshige Ishiwa
- Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8564, Japan
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