Horst D. Schulz Matthias Zabel Marine Geochemistry 2nd revised, updated and extended edition

Horst D. Schulz Matthias Zabel Editors

Marine Geochemistry 2nd revised, updated and extended edition

With 303 Figures, 49 in color

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Professor Dr. Horst D. Schulz Universität Bremen, FB 5 Geowissenschaften Klagenfurter Straße 28359 Bremen Germany Dr. Matthias Zabel Universität Bremen, FB 5 Geowissenschaften Klagenfurter Straße 28359 Bremen Germany

Library of Congress Control Number: 2006920339

ISBN-10 3-540-32143-8 Springer Berlin Heidelberg New York ISBN-13 978-3-540-32143-9 Springer Berlin Heidelberg New York ISBN 3-540-66453-X (1st edition) Springer Berlin Heidelberg New York This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable to prosecution under the German Copyright Law. Springer is a part of Springer Science+Business Media Springeronline.com © Springer-Verlag Berlin Heidelberg 1999, 2006 Printed in Germany The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover design: E. Kirchner, Heidelberg Typesetting: camera-ready by editors Production: Almas Schimmel Printing and binding: Stürtz AG, Würzburg Printed on acid-free paper 32/3141/as 5 4 3 2 1 0

PREFACE 2ND EDITION

Almost six years have passed since the launching of the first edition of this textbook. The friendlyacceptance and brisk demand of the “Marine Geochemistry” have encouraged us to prepare thesecond edition. Six years mean a comparatively long period for a relatively young discipline such asmarine geochemistry. Data and measurements from numerous expeditions, results of different newmethods and techniques, as well as findings of various research programs justify a careful revision ofthe first edition.

The authors of the first edition have revised and substantially updated and enlarged their chapters.We had to give up the partial chapter on sedimentary magnetism of the first edition. In chapter 6 theauthors now concentrate on benthic cycles, and the new co-author Heide N. Schulz especially reportson phosphorus cycles and the microbial parts. Chapter 8 was extended to the complete marine sulfurcycling in connection with anaerobic methane oxidation. Gerhard Bohrmann and Marta E. Torrescontribute their completely new chapter 14 on methane hydrates in marine sediments, representing awell-rounded presentation of this exciting discipline, which will be of major interest in the future.

We also had to consider that other new textbooks (Boudreau and Jørgensen 2001, Fasham 2003,Zhu and Anderson 2002) are now available, whereas revised editions of books (Chester 2000, 2003,Hoefs 2004) were published.

Horst D. Schulz and Matthias Zabel Bremen, November 2005

References

Anderson, R.N., 1986. Marine geology - A planet Earth perspective. Wiley & Sons, NY, 328 pp.Berner, R.A., 1980. Early diagenesis: A theoretical approach. Princeton Univ. Press, Princeton, NY, 241pp.Boudreau, B.P., 1997. Diagenetic models and their impletation: modelling transport and reactions in aquaticsediments. Springer-Verlag, Berlin, Heidelberg, NY, 414 pp.Boudreau, B.P. and Jørgensen, B.B., 2001. The Benthic Boundary Layer. Oxford University Press, 404 pp.Broecker, W.S. and Peng, T.-H., 1982. Tracer in the Sea. Lamont-Doherty Geol. Observation Publ., 690 pp.Chester, R., 1990. Marine Geochemistry. Chapman & Hall, London, 698 pp.Chester, R., 2000, 2003. Marine Geochemistry. Blackwell Science Ltd, Oxford, 2nd ed., pp. 506.Clark, I. and Fritz, P., 1997. Environmental isotopes in hydrogeology. Lewis Publ., NY, 328 pp.Engel, M.H. and Macko, S.A., 1993. Organic Geochemistry. Plenum Press, 861 pp.Faure, G., 1986. Principles of Isotope Geology. Wiley & Sons, NY, 589 pp.Grasshoff, K., Kremling K. and Ehrhardt, M., 1999. Methods of Seawater Analysis. Wiley-VCH, Weinheim, NY,3rd ed., 600 pp.Hoefs, J., 1997. Stable Isotope Geochemistry. Springer, Berlin Heidelberg NY, 4th ed., 201 pp.Hoefs, J., 2004. Stable Isotope Geochemistry. Springer, Berlin Heidelberg NY, 5th ed., 244 pp.Kennett, J.P., 1982. Marine Geology. Prentice Hall, New Jersey, 813 pp.Stumm, W. and Morgan, J.J., 1996. Aquatic Chemistry. Wiley & Sons, 1022 pp.Zhu, C. and Anderson, G., 2002. Environmental Applications of Geochemical Modelling. Cambridge UniversityPress, 284 pp.

PREFACE 1ST EDITION

Today, most branches of science have been extensively described. As to their objectives andinterrelationships they are also well distinguished from the adjoining science disciplines. In this regard,marine geochemistry makes an exception, as does geochemistry in general, for - depending on thescientist’s educational and professional career - this particular field of research can be understood moreor less in terms of geology, chemistry, biology, even mineralogy or oceanography. Despite some occasionalobjection, we conceive our interdisciplinary approach to marine geochemistry rather as an opportunity -even if our own origins most certainly lie in the geosciences. R. Chester (1990) emphasized the chemistryof the water column and the relations to continental inputs in his book on “Marine Geochemistry”. For us,however, the investigation of the marine surface sediments and the (bio)geochemical processes takingplace therein will be of major concern. We therefore see our book as a continuation of whatR.A. Berner (1980) initiated with his classical work “Early Diagenesis”, with which he had a determininginfluence in pointing the way ahead. The concept and the contents we present here is addressed tograduated students of earth science who specialize in marine geochemistry.

Before the background of a continually expanding field of research, it appears impossible for atextbook on marine geochemistry to cope with the task of achieving completeness. Some parts ofmarine geochemistry have been described in more detail elsewhere and with an emphasis placed on adifferent context. These parts were permitted to be treated in brief. The classical subjects of “MarineGeology” are therefore to be found in J.P. Kennet (1982), or with a different perspective inR.N. Andersen (1986). No book on “Aquatic Chemistry” can hardly be better than the one written byW. Stumm and J.J. Morgan (1996). There is furthermore the textbook written by K. Grasshoff,K. Kremling, and M. Ehrhardt (1999) which is concerned with the analytical measurements in seawater.“Tracers in the Sea” by W.S. Broecker and T.-H. Peng (1982) still remains an essential work of standard,albeit a new edition is dearly awaited for. The important field of “Isotope Geochemistry” is exquisitelyrepresented by the books written by G. Faure (1986), Clark and Fritz (1997) and J. Hoefs (1997),as much as “Organic Geochemistry” is represented by the book published by M.H. Engel andS.A. Macko (1993). “Diagenetic Models and Their Implementation” are described from the perspectiveof a mathematician by B.P. Boudreau (1997), owing to which we were able to confine ourselves to thegeochemist’s point of view.

Marine geochemistry is generally integrated into the broad conceptual framework of oceanographywhich encompasses the study of the oceanic currents, their interactions with the atmosphere, weatherand climate; it leads from the substances dissolved in water, to the marine flora and fauna, the processesof plate tectonics, the sediments at the bottom of the oceans, and thus to marine geology. Our notion ofmarine geochemistry is that it is a part of marine geology, wherefore we began our book with a chapteron the solid phase of marine sediments concerning its composition, development and distribution. Thefirst chapter written by Dieter K. Fütterer is therefore a brief summarizing introduction into marinegeology which describes all biochemically relevant aspects related to the subject. Monika Breitzke andUlrich Bleil are concerned in the following chapter with the physical properties of sediments andsedimentary magnetism in a marine-geophysical context, which we deem an important contribution toour understanding of geochemical processes in the sediment.

In the third chapter, Horst D. Schulz demonstrates that the method to quantify biogeochemicalprocesses and material fluxes in recent sediments affords the analysis of the pore-water fraction.Jürgen Rullkötter subsequently gives an overview of organic material contained in sediments whichultimately provides the energy for powering almost all (bio)geochemical reactions in that compartment.The fifth chapter by Bo. B. Jørgensen surveys the world of microorganisms and their actions inmarine sediments. The chapters six, seven, and eight are placed in the order of the oxidative agents

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that are involved in the oxidation of sedimentary organic matter: oxygen and nitrate (Christian Hensenand Matthias Zabel), iron (Ralf R. Haese) and sulfate (Sabine Kasten and Bo. B. Jørgensen). Theyclose the circle of primary reactions that occur in the early diagenesis of oceanic sediments.

In the ninth chapter, marine carbonates are dealt with as a part of the global carbon cycle whichessentially contributes to diagenetic processes (Ralf R. Schneider, Horst D. Schulz and Christian Hensen).Ratios of stable isotopes are repeatedly used as proxy-parametes for reconstructing the paleoclimateand paleoceanography. Hence, in the succeeding chapter, Torsten Bickert discusses the stable isotopesin the marine sediment as well as the processes which bear influence on them. Geoffrey P. Glasby hasdedicated a considerable part of his scientific work to marine manganese. He visited Bremen severaltimes as a guest scientist and therefore it goes without saying that we seized the opportunity to appointhim to be the author of the chapter dealing with nodules and crusts of manganese. Looking at thebenthic fluxes of dissolved and solid/particulate substance across the sediment/water interface, theprocesses of early diagenesis contribute primarily to the material budgets in the world’s oceans and thusto the global material cycles. In chapter 12, Matthias Zabel, Christian Hensen and Michael Schlüter haveventured to make initial methodological observations on global interactions and balances, a subject whichis presently in a state of flux. A summarizing view on hot vents and cold seeps is represented by a chapterwhich is complete in itself . We are indebted to Peter M. Herzig and Mark D. Hannington for havingtaken responsibility in writing this chapter, without which a textbook on marine geochemistry wouldalways have remained incomplete. In the final chapter, conceptual models and their realization intocomputer models are discussed. Here, Horst D. Schulz is more concerned with the biogeochemicalprocesses, their proper comprehension, and with aspects of practical application rather than thedemonstration of ultimate mathematical elegance.

This book could only be written because many contributors have given their support. First of all, wehave to mention the Deutsche Forschungsgemeinschaft in this regard, which has generously fundedour research work in the Southern Atlantic for over ten years. This special research project[Sonderforschungsbereich, SFB 261] entitled “The South Atlantic in the Late Quaternary:Reconstruction of Material Budget and Current Systems”, covered the joint activities of theDepartment of Geosciences at the University Bremen, the Alfred-Wegener-Institute for Polar andMarine Research in Bremerhaven, and the Max-Planck-Institute for Marine Microbiology in Bremen.

The marine-geochemical studies are closely related to the scientific publications submitted by ourcolleagues from the various fields of biology, marine chemistry, geology, geophysics, mineralogy andpaleontology. We would like to thank all our colleagues for the long talks and discussions we hadtogether and for the patient understanding they have showed us as geochemists who were not at alltimes familiar with the numerous particulars of the neighboring sciences.

We were fortunate to launch numerous expeditions within the course of our studies in which severalresearch vessels were employed, especially the RV METEOR. We owe gratitude to the captains andcrews of these ships for their commitment and services even at times when duty at sea was rough. Allchapters of this book were subject to an international process of review. Although all colleaguesinvolved have been mentioned elsewhere, we would like to express our gratitude to them once more atthis point. Owing to their great commitment they have made influential contributions as to contents andcharacter of this book.

Last but not least, we wish to thank our wives Helga and Christine. Although they never had theopportunity to be on board with us on any of the numerous and long expeditions, they still have alwaysunderstood our enthusiasm for marine geochemistry and have always given us their full support.

Horst D. Schulz and Matthias Zabel Bremen, May 1999

Acknowledgements

Along with the authors we are deeply indebted to the reviewers of the first and the second edition.Their helpful comments have considerably improved the contents of this book:

David E. Archer, University of Chicago, USA; Wolfgang H. Berger, Scripps Institution ofOceanography, La Jolla, USA; Ray Binns, CSIRO Exploration & Mining, North Ryde, Australia;Walter S. Borowski, Exxon Exploration Company, Housten, USA; Timothy G. Ferdelman, Max-Planck-Institut für marine Mikrobiologie, Bremen, Germany; Henrik Fossing, National Environmental ResearchInstitute, Silkeborg, Denmark; John M. Hayes, Woods Hole Oceanographic Institution, USA; Bo B.Jørgensen, Max-Planck-Institut für marine Mikrobiologie, Bremen, Germany; David E. Gunn,Southampton Oceanography Centre, United Kingdom; Richard A. Jahnke, Skidaway Institute ofOceanography, Savannah, USA; Karin Lochte, Institut für Ostseeforschung Warnemünde, Germany;Philip A. Meyers, University of Michigan, USA; G.M. McMurtry, University of Hawaii; Jack Middelburg,Netherland Institute of Ecology, Yerske, Netherlands; C.L. Morgan, Planning Solutions, Hawaii; NikolaiPetersen, Universität München, Germany; Christophe Rabouille, Unité Mixte de Recherche CNRS-CEA, Gif-sur-Yvette, France; Jürgen Rullkötter, Universität Oldenburg, Germany; Graham Shimmield,Dunstaffnage Marine Laboratory, Oban, United Kingdom; Ulrich von Stackelberg, Bundesanstalt fürGeowissenschaften und Rohstoffe (BGR), Hannover, Germany; Doris Stüben, Universität Karlsruhe,Germany; Bo Thamdrup, Odense Universitet, Denmark; Cornelis H. van der Weijden, UtrechtUniversity, Netherland; John K. Volkman, CSIRO, Hobart, Tasmania, Australia.

We would also like to express our gratitude to numerous unnamed support staff at the University ofBremen.

Table of Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IX

Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XIX

1 The Solid Phase of Marine SedimentsDIETER K. FÜTTERER

1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Sources and Components of Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . 11.2.1 Lithogenous Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.2.2 Biogenous Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81.2.3 Hydrogenous Sediments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.3 Classification of Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111.3.1 Terrigenous Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121.3.2 Deep-Sea Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131.4 Global Patterns of Sediment Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161.4.1 Distribution Patterns of Shelf Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161.4.2 Distribution Patterns of Deep-Sea Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171.4.3 Distribution Patterns of Clay Minerals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191.4.4 Sedimentation Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221.5 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2 Physical Properties of Marine SedimentsMONIKA BREITZKE

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282.2 Porosity and Wet Bulk Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292.2.1 Analysis by Weight and Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302.2.2 Gamma Ray Attenuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312.2.3 Electrical Resistivity (Galvanic Method) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352.2.4 Electrical Resistivity (Inductive Method) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392.3 Permeability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422.4 Acoustic and Elastic Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422.4.1 Biot-Stoll Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442.4.2 Full Waveform Ultrasonic Core Logging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 472.5 Sediment Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522.5.1 Full Waveform Core Logs as Acoustic Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542.5.2 P- and S-Wave Velocity, Attenuation, Elastic Moduli and Permeability . . . . . . . . . . 54

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2.6 Sediment Echosounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572.6.1 Synthetic Seismograms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572.6.2 Narrow-Beam Parasound Echosounder Recordings . . . . . . . . . . . . . . . . . . . . . . . . . 642.7 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

3 Quantification of Early Diagenesis:Dissolved Constituents in Marine Pore WaterHORST D. SCHULZ

3.1 Introduction: How to Read Pore Water Concentration Profiles . . . . . . . . . . . . 753.2 Calculation of Diffusive Fluxes and Diagenetic Reaction Rates . . . . . . . . . . . . 773.2.1 Steady State and Non-Steady State Situations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 773.2.2 The Steady State Situation and Fick’s First Law of Diffusion . . . . . . . . . . . . . . . . . . 793.2.3 Quantitative Evaluation of Steady State Concentration Profiles . . . . . . . . . . . . . . . . 823.2.4 The Non-Steady State Situation and Fick’s Second Law of Diffusion . . . . . . . . . . . . 873.2.5 The Primary Redox-Reactions: Degradation of Organic Matter . . . . . . . . . . . . . . . . . 883.3 Sampling of Pore Water for Ex-Situ Measurements . . . . . . . . . . . . . . . . . . . . . 903.3.1 Obtaining Samples of Sediment for the Analysis of Pore Water . . . . . . . . . . . . . . . . 903.3.2 Pore Water Extraction from the Sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 933.3.3 Storage, Transport and Preservation of Pore Water . . . . . . . . . . . . . . . . . . . . . . . . . 1013.4 Analyzing Constituents in Pore Water, Typical Profiles . . . . . . . . . . . . . . . . . . 1023.5 In-Situ Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1053.6 Influence of Bioturbation, Bioirrigation, and Advection . . . . . . . . . . . . . . . . . . 1123.7 Signals in the Sediment Solid Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1173.7.1 Analysis of the Sediment’s Solid Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1173.7.2 Interpretation of Element Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1183.7.3 Correlation of Sediment Cores by the Contents of Elements . . . . . . . . . . . . . . . . . 1193.8 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

4 Organic Matter: The Driving Force for Early DiagenesisJÜRGEN RULLKÖTTER

4.1 The Organic Carbon Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1254.2 Organic Matter Accumulation in Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . 1264.2.1 Productivity Versus Preservation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1274.2.2 Primary Production of Organic Matter and Export to the Ocean Bottom . . . . . . . . . . 1284.2.3 Transport of Organic Matter through the Water Column . . . . . . . . . . . . . . . . . . . . . 1304.2.4 The Influence of Sedimentation Rate on Organic Matter Burial . . . . . . . . . . . . . . . . . 1314.2.5 Allochthonous Organic Matter in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . 1324.3 Early Diagenesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1344.3.1 The Organic Carbon Content of Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . 1344.3.2 Chemical Composition of Biomass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1384.3.3 The Principle of Selective Preservation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1424.3.4 The Formation of Fossil Organic Matter and its Bulk Composition . . . . . . . . .. . . . . . 1444.3.5 Early Diagenesis at the Molecular Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1464.3.6 Biological Markers (Molecular Fossils) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

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4.4 Organic Geochemical Proxies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1494.4.1 Total Organic Carbon and Sulfur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1494.4.2 Marine Versus Terrigenous Organic Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1504.4.3 Molecular Paleo-Seawater Temperature and Climate Indicators . . . . . . . . . . . . . . . . 1544.5 Analytical Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1584.5.1 Sample Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1584.5.2 Elemental and Bulk Isotope Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1594.5.3 Rock-Eval Pyrolysis and Pyrolysis Gas Chromatography . . . . . . . . . . . . . . . . . . . . 1594.5.4 Organic Petrography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1594.5.5 Bitumen Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1604.6 The Future of Marine Geochemistry of Organic Matter . . . . . . . . . . . . . . . . . . . 1614.7 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

5 Bacteria and Marine BiogeochemistryBO BARKER JØRGENSEN

5.1 Role of Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1695.1.1 From Geochemistry to Microbiology - and back . . . . . . . . . . . . . . . . . . . . . . . . . . . 1695.1.2 Approaches in Marine Biogeochemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1715.2 Life and Environments at Small Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1735.2.1 Hydrodynamics of Low Reynolds Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1745.2.2 Diffusion at Small Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1745.2.3 Diffusive Boundary Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1755.3 Regulation and Limits of Microbial Processes . . . . . . . . . . . . . . . . . . . . . . . . . . 1765.3.1 Substrate Uptake by Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1775.3.2 Substrate Limitations in the Deep Sub-surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1785.3.3 Temperature as a Regulating Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1795.3.4 Other Regulating Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1805.4 Energy Metabolism of Prokaryotes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1805.4.1 Free Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1825.4.2 Reduction-Oxidation Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1825.4.3 Relations to Oxygen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1845.4.4 Definitions of Energy Metabolism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1845.4.5 Energy Metabolism of Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1855.4.6 Chemolithotrophs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1855.4.7 Respiration and Fermentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1885.5 Pathways of Organic Matter Degradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1895.5.1 Depolymerization of Macromolecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1905.5.2 Aerobic and Anaerobic Mineralization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1905.5.3 Depth Zonation of Oxidants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1925.6 Methods in Biogeochemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1955.6.1 Incubation Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1965.6.2 Radioactive Tracers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1965.6.3 Example: Sulfate Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1985.6.4 Specific Inhibitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1985.6.5 Other Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2005.7 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

XIV

6 Benthic Cycling of Oxygen, Nitrogen and PhosphorusCHRISTIAN HENSEN, MATTHIAS ZABEL AND HEIDE N. SCHULZ

6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2076.2 Distribution of Oxygen, Nitrate and Phosphate in Seawater . . . . . . . . . . . . . . . 2086.3 The Role of Oxygen, Nitrogen and Phosphorus in Marine Sediments . . . . . . . . 2106.3.1 Respiration and Redox Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2106.3.1.1 Nitrification and Denitrification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2106.3.1.2 Coupling of Oxygen and Nitrate to other Redox Pathways . . . . . . . . . . . . . . . . . . . . 2156.3.1.3 Anaerobic Oxidation of Ammonium with Nitrate (Anammox) . . . . . . . . . . . . . . . . . . 2176.3.1.4 Nitrogen Isotopes in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2186.3.2 Input and Redistribution of Phosphate in Marine Sediments . . . . . . . . . . . . . . . . . . 2196.3.2.1 P-Species and Forms of Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2196.3.2.2 Authigenic Formation of Phosphorites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2216.3.2.3 Release of Phosphate by Bacterial Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2216.4 Determination of Consumption Rates and Benthic Fluxes . . . . . . . . . . . . . . . . 2236.4.1 Fluxes and Concentration Profiles Determined by In-Situ Devices . . . . . . . . . . . . . . 2256.4.2 Ex-Situ Pore Water Data from Deep-Sea Sediments. . . . . . . . . . . . . . . . . . . . . . . . 2266.4.3 Determination of Denitrification Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2266.5 Significance and Quantitative Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . 2296.5.1 Estimation of Global Rates and Fluxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2296.5.2 Variation in Different Marine Environments: Case Studies . . . . . . . . . . . . . . . . . . . . 2306.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2346.7 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

7 The Reactivity of IronRALF R. HAESE

7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2417.2 Pathways of Iron Input to Marine Sediments . . . . . . . . . . . . . . . . . .. . . . . . . . . 2417.2.1 Fluvial Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2417.2.2 Aeolian Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2427.3 Iron as a Limiting Nutrient for Primary Productivity . . . . . . . . . . . . . . . . . . . . . 2447.4 The Early Diagenesis of Iron in Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2467.4.1 Dissimilatory Iron Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2477.4.2 Solid Phase Ferric Iron and its Bioavailability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2487.4.2.1 Properties of Iron Oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2487.4.2.2 Bioavailability of Iron Oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2497.4.2.3 Bioavailability of Sheet Silicate Bound Ferric Iron. . . . . . . . . . . . . . . . . . . . . . . . . . . 2517.4.3 Iron Reactivity towards S, O2, Mn, NO3

-, P, HCO3-, and Si-Al . . . . . . . . . . . . . . . . . . 251

7.4.3.1 Iron Reduction by HS- and Ligands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2517.4.3.2 Iron Oxidation by O2, NO3

-, and Mn4+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2537.4.3.3 Iron-Bound Phosphorus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2557.4.3.4 The Formation of Siderite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2557.4.3.5 The Formation of Iron Bearing Aluminosilicates . . . . . . . . . . . . . . . . . . . . . . . . . . . 2567.4.4 Iron and Manganese Redox Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2577.4.5 Discussion: The Importance of Fe- and Mn-Reactivity in Various Environments . . . . . 260

XV

7.5 The Assay for Ferric and Ferrous Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2627.6 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

8 Sulfur Cycling and Methane OxidationBO BARKER JØRGENSEN AND SABINE KASTEN

8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2718.2 Sulfate Reduction and the Degradation of Organic Matter . . . . . . . . . . . . . . . . 2728.2.1 Geochemical Zonation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2738.2.2 Dissimilatory Sul fate Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2748.2.3 Sulfate Reduction and Organic Carbon Mineralization . . . . . . . . . . . . . . . . . . . . . . . 2758.3 Anaerobic Oxidation of Methane (AOM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2788.3.1 The AOM Zone in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2798.3.2 Energy Constraints and Pathway of AOM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2808.3.3 Quantitative Role of AOM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2838.4 Effects of Sulfate Reduction on Sedimentary Solid Phases. . . . . . . . . . . . . . . . 2858.4.1 Reactions with Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2858.4.2 Pyrite Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2858.4.3 Magnetite and Barite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2888.4.4 Non-Steady State Diagenesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2898.5 Pathways of Sulfide Oxidation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2938.6 Determination of Process Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2988.7 The Sulfur Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3008.8 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

9 Marine Carbonates: Their Formation and DestructionRALPH R. SCHNEIDER, HORST D. SCHULZ AND CHRISTIAN HENSEN

9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3119.2 Marine Environments of Carbonate Production and Accumulation . . . . . . . . . . 3119.2.1 Shallow-Water Carbonates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3119.2.2 Pelagic Calcareous Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3159.3 The Calcite-Carbonate-Equilibrium in Marine Aquatic Systems . . . . . . . . . . . . 3179.3.1 Primary Reactions of the Calcite-Carbonate-Equilibrium

with Atmospheric Contact in Infinitely Diluted Solutions . . . . . . . . . . . . . . . . . . . . . . 3189.3.2 Primary Reactions of the Calcite-Carbonate-Equilibrium

without Atmospheric Contact. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3209.3.3 Secondary Reactions of the Calcite-Carbonate-Equilibrium in Seawater . . . . . . . . . 3209.3.4 Examples for Calculation of the Calcite-Carbonate-Equilibrium in Ocean Waters . . . 3219.4 Carbonate Reservoir Sizes and Fluxes between Particulate

and Dissolved Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3249.4.1 Production Versus Dissolution of Pelagic Carbonates . . . . . . . . . . . . . . . . . . . . . . . 3259.4.2 Inorganic and Organic Carbon Release from Deep-Sea Sediments . . . . . . . . . . . . . 3279.5 Problems . . . . . . . . . . . . 334

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10.5 Geochemical Influences on 15N/14N Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

10.5.1 δ15N in Marine Ecosystems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35310.5.2 δ15N in Marine Organic Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35510.6 Geochemical Influences on 34S/32S Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356

10.6.1 δ34S of Seawater and Pore Waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35610.6.2 δ34S in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35910.7 Geochemical Influences on 11B/10B Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360

10.7.1 δ11B of Seawater and Pore Waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36010.7.2 δ11B in Marine Carbonates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36110.8 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362

11 Manganese: Predominant Role of Nodules and CrustsGEOFFREY P. GLASBY

11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37111.2 Manganese, Iron and Trace Elements in Seawater . . . . . . . . . . . . . . . . . . . . . . 37111.3 Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37511.3.1 Manganese, Iron and Trace Elements in Deep-Sea Sediments . . . . . . . . . . . . . . . . 37511.3.2 Diagenetic Processes in Deep-Sea Sediments . . . . . . . . . . . . . . . . . . . . . . . . 37711.4 Manganese Nodules and Crusts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38011.4.1 Deep-Sea Manganese Nodules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38011.4.2 Influence of Diagenesis on Nodule Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38611.4.3 Rare Earth Elements (REE) as Redox Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . 38811.4.4 Co-Rich Mn Crusts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39011.4.5 Shallow-Marine Ferromanganese Concretions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39311.4.6 Hydrothermal Manganese Crusts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39511.4.7 Micronodules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39711.4.8 Mineralogy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398

10 Influences of Geochemical Processes onStable Isotope Distribution in Marine SedimentsTORSTEN BICKERT

10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33910.2 Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33910.2.1 Principles of Isotopic Fractionation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33910.2.2 Analytical Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34010.3 Geochemical Influences on 18O/16O Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

10.3.1 δ18O of Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34110.3.2 δ18O in Marine Carbonates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34310.4 Geochemical Influences on 13C/12C Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346

10.4.1 δ13CΣCO2 of Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34610.4.2 δ13C in Marine Organic Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34710.4.3 δ13C in Marine Carbonates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351

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12.5 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44512.5.1 Balancing the Diffusion Controlled Flux of Benthic Silicate in the South Atlantic -

Applications of Kriging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44512.5.2 Global Distribution of Benthic Oxygen Depletion Rates - An Example of Regression

Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44712.5.3 Use of Numerical Models to Investigate Benthic-Pelagic Coupling . . . . . . . . . . . . . . 45012.6 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45212.7 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 452

13 Input from the Deep: Hot Vents and Cold SeepsPETER M. HERZIG AND MARK D. HANNINGTON

13.1 Hydrothermal Convection and Generation of Hydrothermal Fluidsat Mid-Ocean Ridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459

13.2 Onset of Hydrothermal Activity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46213.3 Growth of Black Smokers and Massive Sulfide Mounds . . . . . . . . . . . . . . . . . . 46213.4 Physical and Chemical Characteristics of Hydrothermal Vent Fluids . . . . . . . . 465

11.4.9 Dating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40011.4.10 Mn Crusts as Paleoceanographic Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40311.4.10.1 Recording Hiatuses in Mn Crusts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40311.4.10.2 Application of Isotopic Studies of Co-rich Mn Crusts to the Study of Present-

day Deep-ocean Circulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40711.4.10.3 Application of Isotopic Studies of Co-rich Mn Crusts to the Study of Paleocean

Circulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41011.4.11 Economic Prospects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41111.4.12 Future Prospects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41411.5 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415

12 Quantification and Regionalization of Benthic RefluxeMATTHIAS ZABEL AND CHRISTIAN HENSEN

12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42912.2 Fundamental Considerations and Assessment Criteria

for Benthic Flux Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43012.2.1 Depth Resolution of Concentration Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43112.2.2 Diffusive versus Total Solute Exchange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43212.2.3 In-Situ versus Ex-Situ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43312.2.4 Time-Dependent Variances and Spatial Variations in the Micro-Environment . . . . . . 43312.3 The Interpretation of Patterns of Regionally Distributed Data . . . . . . . . . . . . . . 43512.3.1 Input and Accumulation of Organic Substance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43512.3.2 Vertical versus Lateral Input of Particulate Matter. . . . . . . . . . . . . . . . . . . . . . . . . . . 43812.3.3 Composition of the Sediment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44012.4 Conceptual Approaches and Methods for Regional Balancing . . . . . . . . . . . . . 44212.4.1 Statistical Key Parameters and Regression Analysis. . . . . . . . . . . . . . . . . . . . . . . . 44212.4.2 Variograms and Kriging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44212.4.3 Geographical Information Systems (GIS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443

XVIII

13.5 The Chemical Composition of Hydrothermal Vent Fluids and Precipitates . . . 46813.6 Characteristics of Cold Seep Fluids at Subduction Zones . . . . . . . . . . . . . . . . . 47213.7 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473

14 Gas Hydrates in Marine SedimentsGERHARD BOHRMANN AND MARTA E. TORRES

14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48214.2 Hydrate Crystal Chemistry and Stability of Gas Hydrates . . . . . . . . . . . . . . . . . 48214.2.1 Cages and Three Crystal Structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48214.2.2 Guest Molecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48314.2.3 Stability and Phase Boundaries of Gas Hydrates . . . . . . . . . . . . . . . . . . . . . . . . . . 48414.3 Hydrate Occurrence in The Oceanic Environment . . . . . . . . . . . . . . . . . . . . . . 48514.3.1 Gas Hydrate Stability Zone in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . 48514.3.2 Seismic Evidence for Gas Hydrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48714.3.3 Generation of Gases for Hydrate Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48814.3.4 Methane Transport and Hydrate Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49014.3.5 Gas Hydrate Accumulation in Sediments and Fabric of Natural Gas Hydrates . . . . . . 49214.4 Pore Water Anomalies Associated with Gas Hydrate Formation and

Decomposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49414.4.1 Gas Hydrate and Chloride Anomalies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49514.4.2 Gas Hydrate and Water Isotope Anomalies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50214.5 Gas Hydrate Carbonate Formation and Anaerobic Oxidation of Methane . . . . . 50314.5.1 Petrographic Characteristics of Clathrites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50314.5.2 Carbonate Precipitation through Microbial Activity . . . . . . . . . . . . . . . . . . . . . . . . . . 50414.6 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50614.7 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507

15 Conceptual Models and Computer ModelsHORST D. SCHULZ

15.1 Geochemical Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51315.1.1 Structure of Geochemical Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51315.1.2 Application Examples of Geochemical Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . 51715.2 Analytical Solutions for Diffusion and Early Diagenetic Reactions . . . . . . . . . . 52315.3 Numerical Solutions for Diagenetic Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52415.3.1 Simple Models with Spreadsheet Software (‘Press-F9-Method’) . . . . . . . . . . . . . . . . 52515.3.2 Two-Step Models with Explicit Numerical Solution of Fick’s 2nd Law. . . . . . . . . . . . . . 52915.3.3 Two-Step Models for Combined Complex Transport/Reaction Processes. . . . . . . . . . 53815.4 Bioturbation and Bioirrigation in Combined Models . . . . . . . . . . . . . . . . . . . . . 54315.5 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545

Answers to ProblemsIndex

Authors

Torsten Bickert Universität Bremen, Fachbereich Geowissenschaften, 28359 Bremen,Germany, bickert@allgeo.uni-bremen.de

Gerhard Bohrmann Universität Bremen, Fachbereich Geowissenschaften, 28359 Bremen,Germany, gbohrmann@uni-bremen.de

Monika Breitzke Alfred-Wegener-Institut für Polar- und Meeresforschung, 27515Bremerhaven, Germany, mbreitzke@awi-bremerhaven.de

Dieter K. Fütterer Alfred-Wegener-Institut für Polar- und Meeresforschung, 27515Bremerhaven, Germany, dfuetterer@awi-bremerhaven.de

Geoffrey P. Glasby Universität Bremen, Fachbereich Geowissenschaften, 28359 Bremen,Germany, g.p.glasby@talk21.com

Ralf R. Haese Marine and Coastal Environment Group Geoscience Australia,Canberra ACT 2601 (Australia), Ralf.Haese@ga.gov.au

Mark. D. Hannington Geological Survey of Canada, Ottawa, Canada,markh@gsc.NRCan.gc.ca

Christian Hensen IFM – GEOMAR, Leibniz-Institut für Meereswissenschaften an derUniversität Kiel, 24105 Kiel, Germany, chensen@ifm-geomar.de

Peter M. Herzig IFM – GEOMAR, Leibniz-Institut für Meereswissenschaften an derUniversität Kiel, 24105 Kiel, Germany, pherzig@ifm-geomar.de

Bo Barker Jørgensen Max-Planck-Institut für marine Mikrobiologie, 28359 Bremen,Germany, bjoergen@mpi-bremen.de

Sabine Kasten Alfred-Wegener-Institut für Polar- und Meeresforschung, 27515Bremerhaven, Germany, skasten@awi-bremerhaven.de

Jürgen Rullkötter Universität Oldenburg, Institut für Chemie und Biologie des Meeres,26111 Oldenburg, Germany, j.rullkoetter@ogc.icbm.uni-oldenburg.de

Ralph R. Schneider Institut für Geowissenschaften, Christian-Albrechts-Universität zuKiel, 24118 Kiel, Germany, schneider@gpi.uni-kiel.de

Heide N. Schulz Universität Hannover, Institut für Mikrobiologie, 30167 Hannover,Germany, schulz@ifmb.uni-hannover.de

Horst D. Schulz Universität Bremen, Fachbereich Geowissenschaften, 28359 Bremen,Germany, hdschulz@uni-bremen.de

Marta E. Torres College of Oceanic and Atmospheric Sciences, Oregon State Univ.,Corvallis OR 97331-5503, USA, mtorres@coas.oregonstate.edu

Matthias Zabel Universität Bremen, Fachbereich Geowissenschaften, 28359 Bremen,Germany, mzabel@uni-bremen.de