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  • 1
    Online Resource
    Online Resource
    Cham :Springer International Publishing AG,
    Keywords: Porous materials. ; Electronic books.
    Description / Table of Contents: This unitary resource sets out the derivation of conservation, thermodynamic, and evolution equations used in modeling multiphase porous media systems. It includes detailed, multiscale applications and a forward-looking discussion of open research issues.
    Type of Medium: Online Resource
    Pages: 1 online resource (609 pages)
    Edition: 1st ed.
    ISBN: 9783319040103
    Series Statement: Advances in Geophysical and Environmental Mechanics and Mathematics Series
    DDC: 620.116015118
    Language: English
    Note: Intro -- Preface -- Contents -- Notation -- Greek Symbols -- Superscripts -- Subscripts -- Other Mathematical Symbols -- Abbreviations -- Chapter 1 Elements of Thermodynamically Constrained Averaging Theory -- 1.1 Overview -- 1.2 Identification of Scales for Modeling -- 1.2.1 Length Scales -- 1.2.2 Time Scales -- 1.3 Thermodynamically Constrained Averaging Theory Approach -- 1.3.1 Overview -- 1.3.2 Microscale Conservation Principles -- 1.3.3 Microscale Thermodynamics -- 1.3.4 Microscale Equilibrium Conditions -- 1.3.5 Averaging Theorems -- 1.3.6 Larger-scale Conservation Principles -- 1.3.7 Larger-scale Thermodynamics -- 1.3.8 Evolution Equations -- 1.3.9 Constrained Entropy Inequality -- 1.3.10 Simplified Entropy Inequality -- 1.3.11 Closure Relations -- 1.3.12 Closed Models -- 1.3.13 Subscale Modeling and Applications -- 1.4 Summary -- Exercises -- References -- Chapter 2 Microscale Conservation Principles -- 2.1 Overview -- 2.2 General Conservation and Balance Principles -- 2.2.1 General Qualitative Formulation -- 2.2.2 General Quantitative Formulation -- 2.2.3 Species-based Quantitative Formulation -- 2.3 Conservation and Balance Principles for a Phase -- 2.3.1 General Microscale Point Forms -- 2.3.2 Specific Conservation and Balance Principles -- 2.4 Conservation and Balance Principles for an Interface -- 2.4.1 General Microscale Point Form -- 2.4.2 Specific Conservation and Balance Principles -- 2.5 Conservation and Balance Principles for a Common Curve -- 2.5.1 General Microscale Point Form -- 2.5.2 Specific Conservation and Balance Principles -- 2.6 General Multispecies Formulation for a Common Point -- 2.6.1 General Microscale Point Form -- 2.7 Summary -- Exercises -- References -- Chapter 3 Microscale Thermodynamics -- 3.1 Overview -- 3.2 Essence of Equilibrium Thermodynamics -- 3.3 Fluid-phase Equilibrium Thermodynamics. , 3.3.1 Fundamental and Differential Forms -- 3.3.2 Euler Equation for Internal Energy -- 3.3.3 Gibbs-Duhem Equation for a Fluid -- 3.4 Normalized Internal Energy Formulation -- 3.5 Other Thermodynamic Potentials -- 3.5.1 Helmholtz Free Energy -- 3.5.2 Enthalpy -- 3.5.3 Gibbs Free Energy -- 3.5.4 Comments on Energy Potentials -- 3.6 Relation between -- and -- 3.7 Solid-phase Equilibrium Thermodynamics -- 3.8 Interface and Common Curve Equilibrium Thermodynamics -- 3.8.1 Interface Thermodynamics -- 3.8.2 Common Curve Thermodynamics -- 3.9 Microscale Multiphase System Notation -- 3.10 Partial Mass Quantities -- 3.10.1 Fluid Phase -- 3.10.2 Solid Phase -- 3.10.3 Interface -- 3.10.4 Common Curve -- 3.11 Classical Irreversible Thermodynamics (CIT) -- 3.12 Other Thermodynamic Theories -- 3.12.1 Rational Thermodynamics (RT) -- 3.12.2 Extended Irreversible Thermodynamics (EIT) -- 3.12.3 Theory of Internal Variables (TIV) -- 3.13 Summary -- Exercises -- References -- Chapter 4 Microscale Equilibrium Conditions -- 4.1 Overview -- 4.2 Components of Variational Analysis -- 4.3 Variation of Microscale Quantities -- 4.3.1 Variation of Green's Strain Tensor -- 4.4 Variation of Energy Integrals -- 4.4.1 Analysis of the Integral of -- 4.4.2 General Condition of Equilibrium -- 4.5 Single-fluid-phase Porous Medium System -- 4.5.1 Equilibrium Conditions -- 4.6 Two-fluid-phase Porous Medium System -- 4.6.1 Identification of Index Sets -- 4.6.2 Identification of Simpler Equilibrium Conditions -- 4.6.3 Equilibrium Variational Analysis -- 4.6.4 Additional Equilibrium Conditions -- 4.7 Summary -- Exercises -- References -- Chapter 5 Microscale Closure for a Fluid Phase -- 5.1 Overview -- 5.2 System Definition -- 5.3 Conservation and Thermodynamic Equations -- 5.3.1 Entropy Inequality -- 5.3.2 Conservation Equations -- 5.3.3 Thermodynamic Relations. , 5.4 Constrained Entropy Inequality -- 5.4.1 Introduction of Constraints -- 5.4.2 Selection of Lagrange Multipliers -- 5.4.3 Reduction to the CEI -- 5.5 Simplified Entropy Inequality -- 5.5.1 Introduction of Approximations -- 5.5.2 Consideration of Equilibrium Conditions -- 5.6 Closure Relations -- 5.6.1 Count of Variables -- 5.6.2 Diffusive Flux Rearrangement -- 5.7 Special Cases -- 5.7.1 Single-species Phase -- 5.7.2 Single-species, Isothermal Phase -- 5.8 Conjugate Force-flux Closure -- 5.8.1 Stress Tensor -- 5.8.2 Diffusion Vector -- 5.8.3 Non-advective Heat Flux -- 5.8.4 Chemical Reaction -- 5.9 Cross-coupled Closure -- 5.10 Summary -- Exercises -- References -- Chapter 6 Macroscale Conservation Principles -- 6.1 Overview -- 6.2 Averaging Conventions and Notation -- 6.2.1 Intrinsic Averages -- 6.2.2 Mass Averages -- 6.2.3 Unique Averages -- 6.2.4 Examples of Averaging Notation -- 6.3 Averaging Theorems -- 6.3.1 Averaging Theorems for Phases -- 6.3.2 Averaging Theorems for Interfaces -- 6.3.3 Averaging Theorems for Common Curves -- 6.3.4 Averaging Theorem for Common Points -- 6.4 Application of Averaging Process -- 6.5 Macroscale Principles for a Phase -- 6.5.1 Conservation of Mass -- 6.5.2 Conservation of Momentum -- 6.5.3 Conservation of Energy -- 6.5.4 Balance of Entropy -- 6.5.5 Body Force Potential -- 6.6 On the Forms of Macroscale Equations -- 6.7 Macroscale Principles for an Interface -- 6.7.1 Example: Conservation of Species Mass -- 6.7.2 Comment on Interface Equations -- 6.8 Macroscale Principles for a Common Curve -- 6.8.1 Example: Conservation of Common Curve Momentum -- 6.8.2 Comment on Common Curve Equations -- 6.9 Mixed Forms of Macroscale Equations -- 6.9.1 Species-based Equations -- 6.9.2 Entity-based Energy and Entropy -- 6.9.3 Entity-based Momentum, Energy, and Entropy -- 6.10 Internal Energy Equation. , 6.10.1 Species- and Entity-based Equations -- 6.10.2 Mixed Formulation with Species Conservation -- 6.11 Summary -- Exercises -- References -- Chapter 7 Macroscale Thermodynamics -- 7.1 Overview -- 7.2 Macroscale Euler Equations -- 7.2.1 Fluid Phase -- 7.2.2 Solid Phase -- 7.2.3 Interface and Common Curve -- 7.3 Macroscale Energy Differentials -- 7.4 Fluid Energy Dynamics -- 7.4.1 Fluid Species Energy -- 7.4.2 Fluid Species Potential Energy -- 7.4.3 Fluid-phase Energy -- 7.4.4 Fluid-phase Potential Energy -- 7.5 Solid-phase Energy Dynamics -- 7.5.1 Solid Species Energy -- 7.5.2 Solid Species Potential Energy -- 7.5.3 Solid-phase Energy -- 7.5.4 Solid-phase Potential Energy -- 7.6 Interface Energy Dynamics -- 7.6.1 Interface Species Energy -- 7.6.2 Interface Species Potential Energy -- 7.6.3 Interface-entity Energy -- 7.6.4 Interface-entity Potential Energy -- 7.7 Common Curve Energy Dynamics -- 7.7.1 Common Curve Species Energy -- 7.7.2 Common Curve Species Potential Energy -- 7.7.3 Common Curve Entity Energy -- 7.7.4 Common Curve Entity Potential Energy -- 7.8 Equilibrium Conditions -- 7.8.1 Two-phase Equilibrium Conditions -- 7.8.2 Three-phase Equilibrium Conditions -- 7.9 Summary -- Exercises -- References -- Chapter 8 Evolution Equations -- 8.1 Overview -- 8.2 Derivation of Evolution Equations -- 8.2.1 General Expression -- 8.3 Single-fluid-phase Flow -- 8.3.1 Phases -- 8.3.2 Interface -- 8.4 Single-fluid-phase Flow Geometric Relations -- 8.5 Two-fluid-phase Flow -- 8.5.1 Solid Phase -- 8.5.2 Fluid Phases -- 8.5.3 Fluid-solid Interfaces -- 8.5.4 Fluid-fluid Interface -- 8.5.5 Common Curve -- 8.6 Two-fluid-phase Flow Geometric Relations -- 8.6.1 Solid Phase and Fluid-solid Interfaces -- 8.6.2 Fluid-fluid Interface Evolution -- 8.6.3 Common Curve Evolution -- 8.7 Average Normal Velocities -- 8.7.1 Fluid-fluid Interface Velocity Approximation. , 8.7.2 Common Curve Velocity Approximation -- 8.8 Summary -- Exercises -- References -- Chapter 9 Single-fluid-phase Flow -- 9.1 Overview -- 9.2 Single-phase-flow System Definition -- 9.3 Conservation and Thermodynamic Equations -- 9.3.1 Entropy Inequality -- 9.3.2 Conservation Equations -- 9.3.3 Thermodynamic Relations -- 9.4 Constrained Entropy Inequality -- 9.4.1 Augmented Entropy Inequality -- 9.4.2 Selection of Lagrange Multipliers -- 9.4.3 Elimination of Time Derivatives -- 9.4.4 Manipulation Insights -- 9.4.5 Formulation of the CEI -- 9.5 Simplified Entropy Inequality -- 9.5.1 The Need for Approximations -- 9.5.2 Elimination of Terms -- 9.5.3 Approximation of Averages -- 9.5.4 General SEI -- 9.6 Example Restricted Application -- 9.6.1 Statement of Secondary Restriction -- 9.6.2 Count of Variables -- 9.6.3 Reduction in Number of Variables -- 9.6.4 Conjugate Force-flux Closure -- 9.6.5 Closed Conservation Equation Set -- 9.7 Model of Fluid and Elastic Solid -- 9.7.1 Compressible Elastic Solid with Small Deformation -- 9.7.2 Passive Solid Phase -- 9.8 Summary -- Exercises -- References -- Chapter 10 Single-fluid-phase Species Transport -- 10.1 Overview -- 10.2 System Definition by Primary Restrictions -- 10.3 Constrained Entropy Inequality -- 10.3.1 Augmented Entropy Inequality -- 10.3.2 Determination of Lagrange Multipliers -- 10.3.3 Formulation of the CEI -- 10.4 Simplified Entropy Inequality -- 10.4.1 Elimination of Small Terms -- 10.4.2 Breaking of Averages -- 10.4.3 General SEI -- 10.5 SEI for Application to Non-isothermal Species Transport -- 10.5.1 Imposition of Secondary Restrictions -- 10.6 Isothermal Transport with No Interphase Mass Exchange -- 10.6.1 Simplification of SEI -- 10.6.2 Count of Equations and Variables -- 10.7 Isothermal Transport with Interphase Mass Exchange -- 10.7.1 Simplification of the SEI. , 10.7.2 Additional Variables and Constraints.
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  • 2
    Keywords: Porous materials Fluid dynamics ; Mathematical models ; Multiphase flow Mathematical models ; Porous materials Fluid dynamics ; Mathematical models ; Multiphase flow Mathematical models ; Porengrundwasserleiter ; Mehrphasenströmung ; Hydraulik ; Grundwasserstrom ; Stoffübertragung ; Modellierung ; Mehrphasenströmung ; Poröser Stoff ; Porengrundwasserleiter ; Hydraulik ; Grundwasserstrom ; Stoffübertragung ; Modellierung
    Type of Medium: Book
    Pages: XIII, 256 S. , Ill., graph. Darst.
    ISBN: 0470317620 , 9780470317624
    DDC: 624.1/513
    RVK:
    Language: English
    Note: Includes index
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  • 3
    Online Resource
    Online Resource
    San Diego :Elsevier Science & Technology,
    Keywords: Hydrology--Mathematical models. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (308 pages)
    Edition: 1st ed.
    ISBN: 9781483270425
    DDC: 551.4/8/018
    Language: English
    Note: Front Cover -- Finite Element Simulation in Surface and Subsurface Hydrology -- Copyright Page -- Table of Contents -- Dedication -- Preface -- Chapter 1. Introduction -- 1.1 Purpose and Scope of the Book -- 1.2 Approximations, Errors, and Significant Figures -- 1.3 Initial Value and Initial Boundary Value Problems -- 1.4 Classification of Partial Differential Equations -- 1.5 Matrix Operations Related to the Finite Element Method -- 1.6 Direct Methods for the Solution of Linear Algebraic Equations -- 1.7 Iterative Methods for the Solution of Linear Algebraic Equations -- References -- Chapter 2. Introduction to Finite Difference Theory -- 2.1 Why Consider Finite Difference Theory? -- 2.2 Finite Difference Approximations -- 2.3 Temporal Finite Difference Approximations -- References -- Chapter 3. The Method of Weighted Residuals -- 3.1 Finite Element Applications -- 3.2 The Fundamentals of Weighted Residual Procedures -- 3.3 Galerkin's Method -- 3.4 Convergence of the Finite Element Method -- 3.5 Approximations in the Time Domain -- 3.6 Summary of Approximation Methods -- References -- Chapter 4. Finite Elements -- 4.1 The Finite Element Concept -- 4.2 Linear Basis Functions -- 4.3 Higher-Degree Polynomial Basis Functions -- 4.4 Hermitian Polynomials -- 4.5 Transient Problem in One Space Variable -- 4.6 Finite Elements in Two Space Dimensions -- 4.7 Relationship between the Finite Element and Finite Difference Methods -- 4.8 Triangular Finite Elements in Two Space Dimensions -- 4.9 Use of Triangular Finite Elements in Two Space Dimensions for Transient Problems -- 4.10 Curved Isoparametric Elements -- 4.11 Three-Dimensional Elements -- 4.12 Odds and Ends -- References -- Chapter 5. Finite Element Method in Subsurface Hydrology -- 5.1 Introduction -- 5.2 Flow of Homogeneous Fluids in Saturated Porous Media. , 5.3 Flow of Nonhomogeneous Fluids in Saturated Porous Media -- 5.4 Saturated-Unsaturated Flows -- 5.5 Saturated-Unsaturated Flow of a Single Fluid -- 5.6 Saturated-Unsaturated Transport -- References -- Chapter 6. Lakes -- 6.1 Introduction -- 6.2 The Equations Which Describe the Flow -- 6.3 Simplified Flow Model -- 6.4 Generalized Flow Model -- 6.5 Hydrothermal Model for Lakes -- 6.6 Conclusions -- References -- Chapter 7. Analysis of Model Behavior -- 7.1 Stability and Consistency -- 7.2 Equations and Restrictions -- 7.3 Analytical Solution -- 7.4 Numerical Solution -- 7.5 Central Implicit Scheme on Linear Elements -- 7.6 Higher-Order Central Implicit Scheme -- 7.7 Alternative Time Stepping Scheme -- 7.8 Uncentered Implicit Scheme -- References -- Chapter 8. Estuaries and Coastal Regions -- 8.1 Scope of the Study -- 8.2 Basic Equations -- 8.3 Linearized Hydrodynamic Model -- 8.4 Implicit Nonlinear Model -- 8.5 Contaminant Transport in Estuaries -- 8.6 Summary -- References -- Index.
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  • 4
    Online Resource
    Online Resource
    Milton :Taylor & Francis Group,
    Keywords: Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (118 pages)
    Edition: 1st ed.
    ISBN: 9781351085922
    Language: English
    Note: Cover -- Title Page -- Copyright Page -- AUTHOR'S INTRODUCTION -- THE AUTHOR -- Table of Conents -- Introduction -- Direct Use of Fungi as Food -- Mushrooms as Human Food -- Fungi as Animal Food -- Use of Fungi in Food Processing -- Fungi in the Processing of Cheese -- Aging and Flavoring of Meat -- Oriental Fungus-Processed Foods -- Potential Additional Uses of Fungi as Food -- Mycelia of Fleshy Fungi -- Mold Type of Mycelium -- Myxomycéte Plasmodia -- Toxic Substances in Fungi -- Stachybotryotoxicosis -- Aspergillustoxicosis -- Moldy Corn Toxicosis -- Facial Eczema in Ruminants -- Alimentary Toxic Aleukia (ATA) -- Estrogenic Condition in Swine -- Toxic Moldy Rice -- Aflatoxin and Other Toxins -- Summation -- Acknowledgments -- References.
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  • 5
    Type of Medium: Book
    Pages: 28 Bl , graph. Darst
    Series Statement: Atmospheric science technical paper 35.1962
    Language: English
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  • 6
    Publication Date: 2019-08-19
    Description: Planktic foraminifera census data have been used to reconstruct past temperatures through transfer functions, as well as changes in ocean ecosystems, chemistry and circulation. Here we present new multinet, plankton net and core-top census data from 20 sites in the Subpolar North Pacific. We combine these with previous data to provide an up to date compilation of North Pacific planktic foraminifera assemblage data. Our compilation is used to define 6 faunal zones: the subpolar zone; transitional zone; upwelling zone; subtropical zone; east equatorial zone; west equatorial zone; based on the distribution of 10 major species of planktic foraminifera. Two species of planktic foraminifera Neogloboquadrina pachyderma and Globigerina bulloides provide the basis for many subpolar paleo-reconstructions. Through the analysis of new multinet and CTD data we find that G. bulloides and N. pachyderma are predominantly found within 0–50 m of the water column and coincide with high food availability. N. pachyderma also shows a strong temperature control and can thrive in food poor waters where temperatures are low. Both species bloom seasonally, particularly during the spring bloom of March to June, with G. bulloides exhibiting greater seasonal variation. We suggest that percentage abundance of N. pachyderma in paleo-assemblages can be used to assess relative changes in past temperature, with G. bulloides abundance more likely to reflect changes in food availability. By comparing our core-top and multinet data, we also find a dissolution bias of G. bulloides over N. pachyderma in the North Pacific, which may enrich assemblages in the latter species.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 7
    Publication Date: 2022-11-06
    Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 36(5), (2022): e2022GB007388, https://doi.org/10.1029/2022gb007388.
    Description: The cycling of biologically produced calcium carbonate (CaCO3) in the ocean is a fundamental component of the global carbon cycle. Here, we present experimental determinations of in situ coccolith and foraminiferal calcite dissolution rates. We combine these rates with solid phase fluxes, dissolved tracers, and historical data to constrain the alkalinity cycle in the shallow North Pacific Ocean. The in situ dissolution rates of coccolithophores demonstrate a nonlinear dependence on saturation state. Dissolution rates of all three major calcifying groups (coccoliths, foraminifera, and aragonitic pteropods) are too slow to explain the patterns of both CaCO3 sinking flux and alkalinity regeneration in the North Pacific. Using a combination of dissolved and solid-phase tracers, we document a significant dissolution signal in seawater supersaturated for calcite. Driving CaCO3 dissolution with a combination of ambient saturation state and oxygen consumption simultaneously explains solid-phase CaCO3 flux profiles and patterns of alkalinity regeneration across the entire N. Pacific basin. We do not need to invoke the presence of carbonate phases with higher solubilities. Instead, biomineralization and metabolic processes intimately associate the acid (CO2) and the base (CaCO3) in the same particles, driving the coupled shallow remineralization of organic carbon and CaCO3. The linkage of these processes likely occurs through a combination of dissolution due to zooplankton grazing and microbial aerobic respiration within degrading particle aggregates. The coupling of these cycles acts as a major filter on the export of both organic and inorganic carbon to the deep ocean.
    Description: This work was funded by NSF OCE-1220301 to W.B., NSF OCE-1220600 to J.F.A., and startup funding for A.V.S.
    Description: 2022-11-06
    Keywords: Calcium carbonate ; Dissolution ; Carbon cycle
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 8
    Publication Date: 2022-05-26
    Description: This is the second part in three of an observational study of tropical oceanic clouds and their relation to the large-scale flow patterns. The first part appeared in preliminary form in 1959 in a volume entitled "Cloud Structure am.d Distributions over the Tropical Pacific. Part I", an unpublished Technical Report (Reference No.58-62) of the Woods Hole Oceanographic Institution. The four authors were the same as those of this report. In addition, a very brief summary of the work (by J. Malkus and C. Ronne) was published in Monograph No.5 of the American Geophysical Union in 1960. A review of the cloud code evolved during this program has been published by M. Alaka in the Bulletin of World Meteorological Organization for April, 1960. The basic material for this study consists of three photographic flights made during July and August 1957 on Military Air Transport (MATS) cargo aircraft flying on regular schedules between San Francisco and the Phillipines. The photographer was Claude Ronne of Woods Hole, accompanied by Joanne Malkus om. the third flight. The appropriate synoptic data were kindly collected by Prof. Colin Ramage of the University of Hawaii and were analyzed by Professor Riehl (then at the University of Chicago) and his colleague Mr. W.S.Gray. The first report described the purposes and methods of the inquiry and presented the results of the first trans-Pacific flight. This report is concerned primarily with the results of the Second flight. A third report on the last flight is planned later, as well as eventual publication of all three parts together. The part of the program reported here has been supported jointly by the Office of Naval Research and the National Science Foundation.
    Description: Office of Naval Research under Contract No. 1721(00) and to the National Science Foundation under Grantt No.7368 with the Woods Hole Oceanographic Institution.
    Keywords: Clouds ; Marine meteorology--Tropics ; Pacific Ocean
    Repository Name: Woods Hole Open Access Server
    Type: Technical Report
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  • 9
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    PANGAEA
    In:  Supplement to: Drury, Anna Joy; Lee, Geoffrey P; Gray, William Robert; Lyle, Mitchell W; Westerhold, Thomas; Shevenell, Amelia E; John, Cédric M (2018): Deciphering the state of the late Miocene to early Pliocene equatorial Pacific. Paleoceanography and Paleoclimatology, 33, 246-263, https://doi.org/10.1002/2017PA003245
    Publication Date: 2023-03-06
    Description: The late Miocene-early Pliocene was a time of global cooling and the development of modern meridional thermal gradients. Equatorial Pacific sea surface conditions potentially played an important role in this global climate transition, but their evolution is poorly understood. Here, we present the first continuous late Miocene-early Pliocene (8.0-4.4 Ma) planktic foraminiferal stable isotope records from eastern equatorial Pacific Integrated Ocean Drilling Program Site U1338, with a new astrochronology spanning 8.0-3.5 Ma. Mg/Ca analyses on surface dwelling foraminifera Trilobatus sacculifer from carefully selected samples suggest mean sea-surface-temperatures (SSTs) are ~27.8±1.1°C (1 Sigma) between 6.4-5.5 Ma. The planktic foraminiferal d18O record implies a 2°C cooling between 7.2-6.1 Ma and an up to 3°C warming between 6.1-4.4 Ma, consistent with observed tropical alkenone paleo-SSTs. Diverging fine-fraction-to-foraminiferal d13C gradients likely suggest increased upwelling from 7.1-6.0 and 5.8-4.6 Ma, concurrent with the globally recognized late Miocene Biogenic Bloom. This study shows that both warm and asymmetric mean states occurred in the equatorial Pacific during the late Miocene-early Pliocene. Between 8.0-6.5 and 5.2-4.4 Ma, low east-west d18O and SST gradients and generally warm conditions prevailed. However, an asymmetric mean climate state developed between 6.5-5.7 Ma, with larger east-west d18O and SST gradients and eastern equatorial Pacific cooling. The asymmetric mean state suggests stronger trade winds developed, driven by increased meridional thermal gradients associated with global cooling and declining atmospheric pCO2 concentrations. These oscillations in equatorial Pacific mean state are reinforced by Antarctic cryosphere expansion and related changes in oceanic gateways (e.g., Central American Seaway/Indonesian Throughflow restriction).
    Keywords: Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP
    Type: Dataset
    Format: application/zip, 5 datasets
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  • 10
    facet.materialart.
    Unknown
    PANGAEA
    In:  Supplement to: Taylor, Ben J; Rae, James W B; Gray, William Robert; Darling, Kate F; Burke, Andrea; Gersonde, Rainer; Abelmann, Andrea; Maier, Edith; Esper, Oliver; Ziveri, Patrizia (2018): Distribution and ecology of planktic Foraminifera in the North Pacific: Implications for paleo-reconstructions. Quaternary Science Reviews, 191, 256-274, https://doi.org/10.1016/j.quascirev.2018.05.006
    Publication Date: 2023-03-06
    Description: Planktic foraminifera census data have been used to reconstruct past temperatures through transfer functions, as well as changes in ocean ecosystems, chemistry and circulation. Here we present new multinet, plankton net and core-top census data from 20 sites in the Subpolar North Pacific. We combine these with previous data to provide an up to date compilation of North Pacific planktic foraminifera assemblage data. Our compilation is used to define 6 faunal zones: the subpolar zone; transitional zone; upwelling zone; subtropical zone; east equatorial zone; west equatorial zone; based on the distribution of 10 major species of planktic foraminifera. Two species of planktic foraminifera Neogloboquadrina pachyderma and Globigerina bulloides provide the basis for many subpolar paleo-reconstructions. Through the analysis of new multinet and CTD data we find that G. bulloides and N. pachyderma are predominantly found within 0-50 m of the water column and coincide with high food availability. N. pachyderma also shows a strong temperature control and can thrive in food poor waters where temperatures are low. Both species bloom seasonally, particularly during the spring bloom of March to June, with G. bulloides exhibiting greater seasonal variation. We suggest that percentage abundance of N. pachyderma in paleo-assemblages can be used to assess relative changes in past temperature, with G. bulloides abundance more likely to reflect changes in food availability. By comparing our core-top and multinet data, we also find a dissolution bias of G. bulloides over N. pachyderma in the North Pacific, which may enrich assemblages in the latter species.
    Keywords: AWI
    Type: Dataset
    Format: application/zip, 6 datasets
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