DOCSLIB.ORG

University of Southampton Research Repository Eprints Soton

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
University of Southampton Research Repository Eprints Soton University of Southampton Research Repository ePrints Soton Copyright © and Moral Rights for this thesis are retained by the author and/or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder/s. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given e.g. AUTHOR (year of submission) "Full thesis title", University of Southampton, name of the University School or Department, PhD Thesis, pagination http://eprints.soton.ac.uk UNIVERSITY OF SOUTHAMPTON FACULTY OF NATURAL AND ENVIRONMENTAL SCIENCES Ocean and Earth Sciences Investigating the drivers of perturbations to the Cenozoic carbon-climate system by David Ian Armstrong McKay Thesis for the degree of Doctor of Philosophy August 2015 UNIVERSITY OF SOUTHAMPTON ABSTRACT FACULTY OF NATURAL AND ENVIRONMENTAL SCIENCES Ocean and Earth Sciences Thesis for the degree of Doctor of Philosophy INVESTIGATING THE DRIVERS OF PERTURBATIONS TO THE CENOZOIC CARBON-CLIMATE SYSTEM David Ian Armstrong McKay Over the course of the Cenozoic the Earth system has shifted from a CO2-rich ‘Greenhouse’ climate state to a CO2-poor ‘Icehouse’ climate state. This trend is punctuated by numerous perturbations to the carbon-climate system, but the extent of the coupling between the carbon cycle and climate system, the drivers of these perturbations, and their relationship to the longer-term Cenozoic trend is still debated. In this thesis, I use biogeochemical modelling and numerical analysis to explore the key research question: ‘What were the drivers of carbon-climate system perturbations during the Cenozoic?’, with a focus on perturbations during the Eocene- Oligocene Transition and the mid-Miocene, the role of tipping points during these periods, and the long-term evolution of the ocean carbonate system. The potential impact of the Columbia River Basalt large igneous province on the mid-Miocene Earth system is investigated using two biogeochemical box models. This modelling indicates that ‘cryptic degassing’ from intrusive and/or crust-contaminated magma of a magnitude within the estimated possible range can drive the observed carbon cycle perturbation and warming around 16.0 Ma, but cannot by itself explain other features of the mid-Miocene palaeorecords. The hypothesised drivers of the Eocene-Oligocene Transition (EOT) carbon cycle perturbation are explored using a biogeochemical box model. The results suggest that the glacioeustatic fractionation of carbonate burial from shelf to basin can explain most of the deepening of the carbonate compensation depth (CCD) at the EOT, but that the benthic carbon isotope excursion most likely requires additional drivers. The shelf-basin carbonate burial fractionation hypothesis is examined further in order to quantify the relationship between shelf carbonate burial extent, the CCD, and changing sea-level during the Cenozoic. This analysis confirms that carbonate burial fractionation can drive most of the CCD deepening at the EOT but is less important either before or since then, and also indicates that the sensitivity of the CCD to sea level change has significantly declined during the Cenozoic. Palaeorecords of a number of perturbations to the carbon-climate system during the Cenozoic are analysed in search for ‘early warning signals’ (EWS) indicative of systemic instability and impending critical transitions, and the reliability of this method when applied to palaeorecords is critically explored. EWS are found prior to some (e.g. the EOT and Palaeocene-Eocene Thermal Maximum) but not all of the events, and the results and technique are judged to be moderately reliable. Table of Contents Table of Contents ................................................................................................... i List of Tables .......................................................................................................... v List of Figures ..................................................................................................... vii Declaration of Authorship ............................................................................. xiii Acknowledgements ............................................................................................ xv Some thoughts on modelling, complexity and climate change ....... xvii List of Abbreviations and Symbols ............................................................. xix Chapter 1: Introduction and Background .............................................. 1 1.1 The Goldilocks question ............................................................................. 1 1.2 Cenozoic climate change ............................................................................ 3 1.2.1 Long-term Cenozoic cooling ......................................................... 3 1.2.2 Abrupt climate shifts .................................................................... 5 1.2.3 Cenozoic climate chronology ........................................................ 6 1.2.4 Palaeoclimatology and the Anthropocene ................................. 8 1.3 The geological carbon cycle: conceptual and numerical models .......... 9 1.3.1 A conceptual model of the carbon cycle ..................................... 9 1.3.2 Numerical models of the carbon cycle ...................................... 16 1.4 Thesis aims and structure ....................................................................... 23 1.4.1 Key research questions ............................................................... 23 1.4.2 Thesis structure ........................................................................... 24 Chapter 2: Estimating the impact of the cryptic degassing of Large Igneous Provinces: A mid-Miocene case-study ........................ 25 2.1 Abstract ...................................................................................................... 25 2.2 Introduction ............................................................................................... 26 2.3 The mid-Miocene and the Columbia River Basalt eruptions ............. 28 2.4 Materials and Methods ............................................................................ 30 2.4.1 Modelling ...................................................................................... 30 2.4.2 MTW08 sensitivity analyses...................................................... 32 i 2.4.3 Eruption chronology ................................................................... 32 2.4.4 Cryptic degassing estimates ...................................................... 33 2.5 Results and Discussion ............................................................................ 37 2.5.1 Modelled emission scenario ....................................................... 38 2.5.2 The CCD and the mid-Miocene Climate Transition .............. 40 2.5.3 Mid-Miocene climate change ..................................................... 41 2.6 Conclusions ................................................................................................ 43 2.7 Acknowledgements ................................................................................... 43 2.8 Supporting Information ........................................................................... 44 2.8.1 Model parameters ....................................................................... 44 2.8.2 Sensitivity analyses .................................................................... 46 Chapter 3: Global carbon cycle perturbation across the Eocene- Oligocene climate transition .......................................................... 49 3.1 Abstract ...................................................................................................... 49 3.2 Background ................................................................................................ 50 3.2.1 The Eocene-Oligocene Transition ............................................. 50 3.2.2 Potential drivers of the EOT carbon cycle perturbation ....... 51 3.2.3 Study aims ................................................................................... 55 3.3 Method ........................................................................................................ 55 3.3.1 Modelling ...................................................................................... 55 3.3.2 Hypotheses ................................................................................... 56 3.4 Results and Discussion ............................................................................ 58 3.4.1 Scenarios ...................................................................................... 58 3.4.2 Implications ................................................................................. 68 3.5 Conclusions ................................................................................................ 71 3.6 Acknowledgements ................................................................................... 72 3.7 Supporting Information ........................................................................... 73 3.7.1 The SWC scenario and the climate-weathering feedback .... 73 3.7.2 Extra calcium input feedbacks ................................................
Load more

Recommended publications
  • The Crazy Calcium Cycle. Eduardo A. Espeso Department of Cellular And
    The CRaZy calcium cycle. Eduardo A. Espeso Department of Cellular and Molecular Biology Centro de Investigaciones Biológicas, CSIC. Ramiro de Maeztu, 9. 28040-Madrid. Spain. Key words: Crz1, calcineurin signaling, calcium pump, calcium channel, P-type ATPase, magnesium homeostasis Summary. Calcium is an essential cation for a cell. This cation participates in the regulation of numerous processes in either prokaryote s or eukaryotes, from bacteria to humans. Saccharomyces cerevisiae has served as a model organism to understand calcium homeostasis and calcium-dependent signaling in fungi. In this chapter it will be reviewed known and predicted transport mechanisms that mediate calcium homeostasis in the yeast. How and when calcium enters the cell, how and where it is stored, when is reutilized, and finally secreted to the environment to close the cycle. As a second messenger, maintenance of a controlled free intracellular calcium concentration is important for mediating transcriptional regulation. Many environmental stimuli modify the concentration of cytoplasmic free calcium generating the "calcium signal". This is sensed and transduced through the calmodulin/calcineurin pathway to a transcription factor, named c alcineurin-r esponsive z inc finger, CRZ, also known as "crazy" , to mediate transcriptional regulation of a large number of genes of diverse pathways including a negative feedback regulation of the calcium homeostasis system. A model of calcium regulation in yeasts In higher eukaryotes entry of calcium in the cell starts concatenated signaling events some of them are of enormous importance in animals such as initiation of the heartbeat or the synapses between neurons. In the budding yeast calcium mediates adaptation to a variety of stimuli such as the presence of mating pheromones (Iida et al., 1990), a damage to endoplasmic reticulum (Bonilla and Cunningham, 2003), and different ambient stresses like salinity, alkaline pH or high osmolarity [reviewed in (Cunningham, 2005)].
    [Show full text]
  • The Calcium Cycle
    Curriculum Units by Fellows of the Yale-New Haven Teachers Institute 1985 Volume VII: Skeletal Materials- Biomineralization The Calcium Cycle Curriculum Unit 85.07.08 by Bill Duesing INTRODUCTION This unit is designed to be part of the Ecology course which is taught by High School in the Community at the West Rock Nature Center for four hours a day during the last quarter of the school year, The present ecology course involves both theoretical and practical studies relating to the earth and how it works. We will trace calcium in the biosphere from its location in igneous rocks in the early history of the earth to its location in the skeletons of high school students at the Nature Center. In the process of studying the transport and deposition of calcium we have a vehicle which touches on many of the important concepts we are teaching and relates to some of the hands-on activities the students are involved in. Some of the connections between the calcium cycle and the Ecology course are: Geology: Many of the students have no idea of the age and history of the earth and the great changes which it has gone through. How the calcium stored in the rocks in northwestern Connecticut came to be there touches on much of this chemistry: Most of the students have had very little exposure to chemistry, yet it is important in the study of ecology. Using the study of calcium, some simple chemical principles can be introduced such as the fact that calcium is intimately associated with carbon dioxide (CO2), as the solid calcium carbonate (CaCO3), and therefore is involved with life and life forms.
    [Show full text]
  • Calcium Isotopes in Scleractinian Fossil Corals Since the Mesozoic: Implications for Vital Effects and Biomineralization Through Time ∗ Anne M
    Earth and Planetary Science Letters 444 (2016) 205–214 Contents lists available at ScienceDirect Earth and Planetary Science Letters www.elsevier.com/locate/epsl Calcium isotopes in scleractinian fossil corals since the Mesozoic: Implications for vital effects and biomineralization through time ∗ Anne M. Gothmann a, , Michael L. Bender a, Clara L. Blättler a, Peter K. Swart b, Sharmila J. Giri b, Jess F. Adkins c, Jarosław Stolarski d, John A. Higgins a a Princeton University, Department of Geosciences, Princeton, NJ, USA b University of Miami, Department of Marine Geosciences, Miami, FL, USA c California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA, USA d Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland a r t i c l e i n f o a b s t r a c t 44/40 Article history: We present a Cenozoic record of δ Ca from well preserved scleractinian fossil corals, as well as fossil 44/40 Received 24 September 2015 coral δ Ca data from two time periods during the Mesozoic (84 and 160 Ma). To complement the Received in revised form 27 February 2016 coral data, we also extend existing bulk pelagic carbonate records back to ∼80 Ma. The same fossil Accepted 6 March 2016 corals used for this study were previously shown to be excellently preserved, and to be faithful archives Available online 7 April 2016 44/40 of past seawater Mg/Ca and Sr/Ca since ∼200 Ma (Gothmann et al., 2015). We find that the δ Ca Editor: H. Stoll compositions of bulk pelagic carbonates from ODP Site 807 (Ontong Java Plateau) and DSDP Site 516 (Rio 44/40 Keywords: Grande Rise) have not varied by more than ∼±0.20h over the last ∼80 Myr.
    [Show full text]
  • Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions
    Article Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions Guilin Han 1,* , Anton Eisenhauer 2, Jie Zeng 1 and Man Liu 1 1 Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing 100083, China; [email protected] (J.Z.); [email protected] (M.L.) 2 GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany; [email protected] * Correspondence: [email protected]; Tel.: +86-10-82-323-536 Abstract: In order to better constrain calcium cycling in natural soil and in soil used for agriculture, we present the δ44/40Ca values measured in rainwater, groundwater, plants, soil, and bedrock samples from a representative karst forest in SW China. The δ44/40Ca values are found to differ by ≈3.0‰ in the karst forest ecosystem. The Ca isotope compositions and Ca contents of groundwater, rainwater, and bedrock suggest that the Ca of groundwater primarily originates from rainwater and bedrock. The δ44/40Ca values of plants are lower than that of soils, indicating the preferential uptake of light Ca isotopes by plants. The distribution of δ44/40Ca values in the soil profiles (increasing with soil depth) suggests that the recycling of crop-litter abundant with lighter Ca isotope has potential effects on soil Ca isotope composition. The soil Mg/Ca content ratio probably reflects the preferential plant uptake of Ca over Mg and the difference in soil maturity. Light Ca isotopes are more abundant 40 Citation: Han, G.; Eisenhauer, A.; in mature soils than nutrient-depleted soils. The relative abundance in the light Ca isotope ( Ca) is Zeng, J.; Liu, M.
    [Show full text]
  • Cellular Calcium Pathways and Isotope Fractionation in Emiliania
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE Cellular calcium pathways and isotope fractionation inprovided by Electronic Publication Information Center Emiliania huxleyi Nikolaus Gussone Research Centre Ocean Margins, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany Gerald Langer ⎤ Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Silke Thoms ⎥ Germany Gernot Nehrke ⎦ Anton Eisenhauer Leibniz Institute of Marine Sciences at the University of Kiel, Dienstgeba¨ude Ostufer, Wischhofstraße 1-3, 24148 Kiel, Germany Ulf Riebesell Leibniz Institute of Marine Sciences at the University of Kiel, Dienstgeba¨ude Westufer, Du¨sternbrooker Weg 20, 24105 Kiel, Germany Gerold Wefer Research Centre Ocean Margins, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany ABSTRACT in coccolithophores, because previous work indicates a strong kinetic 2Ϫ The marine calcifying algae Emiliania huxleyi (coccolitho- effect of the carbonate ion concentration [CO3 ] on calcium isotope 2Ϫ phores) was grown in laboratory cultures under varying conditions fractionation (Lemarchand et al., 2004). Since reduced [CO3 ] leads with respect to the environmental parameters of temperature and to a decrease in calcification rate of Emiliania huxleyi (Riebesell et al., 2؊ carbonate ion concentration [CO3 ] concentration. The Ca isotope 2000), it should also be reflected in the Ca isotopic composition of composition of E. huxleyi’s coccoliths reveals new insights the coccolith. The apparent temperature dependence on Ca isotope 2Ϫ into fractionation processes during biomineralization. The fractionation was also proposed to be caused by [CO3 ] via the temperature-dependent Ca isotope fractionation resembles previ- temperature-dependent dissociation of carbonic acid (Lemarchand et ous calibrations of inorganic and biogenic calcite and aragonite.
    [Show full text]
  • Coupled Nitrogen and Calcium Cycles in Forests of the Oregon Coast Range
    Ecosystems (2006) 9: 63–74 DOI: 10.1007/s10021-004-0039-5 Coupled Nitrogen and Calcium Cycles in Forests of the Oregon Coast Range Steven S. Perakis,1,2* Douglas A. Maguire,2 Thomas D. Bullen,3 Kermit Cromack,2 Richard H. Waring,2 and James R. Boyle2 1US Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, Oregon 97331, USA; 2Department of Forest Science, Oregon State University, Corvallis, Oregon 97333, USA; 3US Geological Survey, Branch of Regional Research, Water Resources Discipline, Menlo Park, California 94025, USA ABSTRACT Nitrogen (N) is a critical limiting nutrient that concentrations are highly sensitive to variations in regulates plant productivity and the cycling of soil Ca across our sites. Natural abundance calcium other essential elements in forests. We measured isotopes (d44Ca) in exchangeable and acid leach- foliar and soil nutrients in 22 young Douglas-fir able pools of surface soil measured at a single site stands in the Oregon Coast Range to examine showed 1 per mil depletion relative to deep soil, patterns of nutrient availability across a gradient of suggesting strong Ca recycling to meet tree de- N-poor to N-rich soils. N in surface mineral soil mands. Overall, the biogeochemical response of ranged from 0.15 to 1.05% N, and was positively these Douglas-fir forests to gradients in soil N is related to a doubling of foliar N across sites. Foliar N similar to changes associated with chronic N in half of the sites exceeded 1.4% N, which is deposition in more polluted temperate regions, and considered above the threshold of N-limitation in raises the possibility that Ca may be deficient on coastal Oregon Douglas-fir.
    [Show full text]
  • 1 Constraining Calcium Isotope Fractionation (Δ44/40Ca) in Modern and Fossil Scleractinian Coral Skeleton
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by OceanRep Constraining calcium isotope fractionation (δ44/40Ca) in modern and fossil scleractinian coral skeleton. Pretet Chloé, Samankassou Elias, Felis Thomas, Reynaud Stéphanie, Böhm Florian, Eisenhauer Anton, Ferrier-Pagès Christine, Gattuso Jean-Pierre, Camoin Gilbert Preprint Chemical Geology doi : 10.1016/j.chemgeo.2012.12.006 in press December, 19, 2012 1 Constraining calcium isotope fractionation (δ44/40Ca) in modern and fossil scleractinian coral skeleton. Pretet Chloé1, Samankassou Elias1, Felis Thomas2, Reynaud Stéphanie3, Böhm Florian4, Eisenhauer Anton4, Ferrier-Pagès Christine3, Gattuso Jean-Pierre5, Camoin Gilbert6 1: Section of Earth and Environmental Sciences, University of Geneva, Rue des Maraîchers 13, CH-1205 Geneva, Switzerland 2: MARUM, Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany 3: Centre Scientifique de Monaco, Avenue Saint-Martin, 98000, Monaco 4: Helmholtz Zentrum für Ozeanforschung (GEOMAR), Wischhofstr. 1-3, 24148 Kiel, Germany 5: Université Pierre et Marie Curie-Paris 6, Observatoire Océanologique de Villefranche, 06230 Villefranche-sur-Mer, France / CNRS-INSU, Laboratoire d'Océanographie de Villefranche, BP 28, 06234 Villefranche sur-Mer Cedex, France 6 : CEREGE, UMR 6635, CNRS, BP 80, F-13545 Aix en Provence cedex 4, France 2 Abstract The present study investigates the influence of environmental (temperature, salinity) and biological (growth rate, inter-generic variations) parameters on calcium isotope fractionation (δ44/40Ca) in scleractinian coral skeleton to better constrain this record. Previous studies focused on the δ44/40Ca record in different marine organisms to reconstruct seawater composition or temperature, but only few studies investigated corals.
    [Show full text]
  • Paleogene Calcite Compensation Depth in the Eastern Subtropical Pacific: Answers and Questions David K
    PALEOCEANOGRAPHY, VOL. 20, PA1012, doi:10.1029/2004PA001064, 2005 Paleogene calcite compensation depth in the eastern subtropical Pacific: Answers and questions David K. Rea Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan, USA Mitchell W. Lyle Center for the Geophysical Investigation of the Shallow Subsurface, Boise State University, Boise, Idaho, USA Received 23 June 2004; revised 2 November 2004; accepted 30 November 2004; published 19 February 2005. [1] Ocean Drilling Program Leg 199 drilled a north-south transect across the Eocene paleoequator in the eastern Pacific, permitting reconstruction the calcite compensation depth (CCD) since earliest Eocene time. The CCD was relatively shallow near the early Eocene Pacific equator, 3200 m, and unlike modern latitudinal CCD gradients deepened to the north (to 3600 m; paleolatitude 10°N). At 41 Ma the CCD underwent a brief, sharp, transient deepening of 700 m, then remained shallow until the Eocene/Oligocene boundary. At the E/O boundary, the CCD deepened by 1200 m in less than 300 kyr. This rapid deepening served to more than double the area of seafloor subject to CaCO3 deposition. Sea level fall associated with ice volume buildup, and ensuing shelf-basin fractionation, is unlikely to be the sole cause of the increased deep-ocean CaCO3 burial; rather, a sudden, rapid increase in the amount of Ca entering the ocean appears necessary to explain the observations. Citation: Rea, D. K., and M. W. Lyle (2005), Paleogene calcite compensation depth in the eastern subtropical Pacific: Answers and questions, Paleoceanography, 20, PA1012, doi:10.1029/2004PA001064. 1. Introduction the CCD, such as those on the Ontong-Java Plateau, Shatsky Rise, Ceara Rise, Demerara Rise and Walvis Ridge.
    [Show full text]
  • Calcification of Selected Coccolithophore Species: Strontium Partitioning, Calcium Isotope Fractionation and Dependence on Seawater Carbonate Chemistry
    Calcification of selected coccolithophore species: strontium partitioning, calcium isotope fractionation and dependence on seawater carbonate chemistry Dissertation zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften - Dr. rer. nat. - am Fachbereich 2 (Biologie/Chemie) der Universität Bremen vorgelegt von Gerald Langer Bremen, September 2005 "If entire coccospheres are examined ..... it will be found that numerically about 80 per cent. of them contain an internal oval colourless body. Closer examination reveals that this body is in many cases a complete and perfect coccolith....." (Dixon 1900) TABLE OF CONTENTS 1 General Introduction 1 1.1 Coccolithophores 1 1.2 Calcification of coccolithophores 4 1.3 Biogenic calcium carbonate based proxies – a biased selection 8 1.4 The seawater carbonate system 11 1.5 Marine calcifiers and seawater carbonate chemistry 13 1.6 Outline of the thesis 16 1.7 References 17 2 Publications 27 2.1 List of publications 27 2.2 Declaration on the contribution of each publication 28 I Coccolith strontium to calcium ratios in Emiliania huxleyi: The dependence on seawater strontium and calcium concentrations 31 II Temperature dependent calcium isotope fractionation in coccoliths of cultured Calcidiscus leptoporus, Helicosphaera carteri, Syracosphaera pulchra and Umbilicosphaera foliosa 65 III Calcium isotope fractionation during coccolith formation in Emiliania huxleyi 85 IV Coccolithophore calcification adapting to changes in oceanic CO2 levels 111 3 General Discussion 139 3.1 Sr/Ca of coccoliths – implications for proxy use and biomineralisation 139 3.2 δ44/40Ca of coccoliths – implications for proxy use and biomineralisation 141 3.3 Coccolithophore calcification and ocean acidification 144 3.4 Perspectives for future research 146 3.5 References 148 4 Summary 153 5 Zusammenfassung 157 6 Danksagung 161 GENERAL INTRODUCTION 1 1 General Introduction 1.1 Coccolithophores Oceans cover roughly seventy percent of the earth’s surface.
    [Show full text]
  • Calcification Patterns of the Coccolithophore Coccolithus Braarudii (Haptophyta), from the Late Quaternary to Present in the Southern Ocean
    Calcification patterns of the coccolithophore Coccolithus braarudii (Haptophyta), from the late Quaternary to present in the Southern Ocean by Joana Carolina Cubillos BSc. Hons., University of Tasmania Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy University of Tasmania June, 2013 Declaration of Originality I declare that the material presented in this thesis is original, except where due acknowledgement is given, and has not been accepted for award of any other degree or diploma ___________________________ Joana Carolina Cubillos June, 2013 i Authority of Access This thesis may be available for loan and limited copying in accordance with the Copyright Act 1968 ___________________________ Joana Carolina Cubillos June, 2013 ii Statement regarding published work contained in the thesis The publishers of the paper comprising Chapter 2 hold the copyright for that content, and access to the material should be sought from the respective journals. The remaining non-published content of the thesis may be made available for loan and limited copying and communication in accordance with the Copyright Act 1968. iii Statement of authorship (Chapter 2) The following people contributed to the publication of the work undertaken as part of this thesis: Joana C. Cubillos (candidate) (50%), Jorijntje Henderiks (author 2) (35%), Luc Beaufort (author 3) (2.5%), Will R. Howard (author 4) (2.5%), Gustaaf Hallegraeff (author 5) (10%) Details of authors roles: Joana C. Cubillos (the candidate) and Jorijntje Henderiks contributed to the idea, method development and method refinement, presentation and formalization. Luc Beaufort contributed to the original idea and training on the original methodology. Gustaaf Hallegraeff contributed with his expertise, feedback, laboratory facilities, presentation and formalization.
    [Show full text]
  • Nutrient Cycles in Marine Ecosystems
    Nutrient Cycles in Marine Ecosystems Chapter 4 Nitrogen, Carbon, Magnesium, Calcium, Phophorous Chapter 4 vocabulary 1. Nutrient 6. Assimilation 11.Leaching 2. Decomposer 7. Residence time 12.Marine snow 3. Reservoir 8. Sink 13.Dissociation 4. Run-off 9. Source 14.Diazotroph 5. Upwelling 10.Infiltration 15.Saprophytic Cycling of elements in the ecosystem Nutrient cycles move nutrients that are essential for life through the food chain through feeding. Nutrients: a chemical that provides what is needed for organisms to live and grow. When organisms die, decomposers break down the organic tissue and return it to inorganic forms. (inorganic forms could remain in ecosystem for millions of years before being synthesized into organic forms) Decomposer: bacteria and fungi that break down dead organic matter and release the nutrients back into the environment. The ocean is a reservoir for elements….. Reservoir: part of the abiotic phase of the nutrient cycle where nutrients can remain for long periods of time. Producers and microorganisms are able to fix inorganic molecules to organic substances. In this way… the abiotic part of the cycle can be moved into the biotic. (Fecal matter/dead organisms) Some are added to coral reefs and/or removed from the ocean altogether from harvesting. Molecules are added in through run-off and upwelling. Run-off: the flow of water from land caused by precipitation Upwelling: the movement of cold, nutrient rich water from deep in the ocean to the surface CONSUMERS BIOTIC PHASE PRIMARY DECOMPOSERS PRODUCERS ABIOTIC PHASE Nutrients found as inorganic ions and compounds in the atmosphere, dissolved in water, forming rocks and sediments Nutrient cycles Nutrients move from from the abiotic to the biotic when nutrients are absorbed and assimilated by producers Assimilation: the conversion of a nutrient into a usable form that can be incorporated into the tissues of an organism.
    [Show full text]
  • Role of Calcium Signaling in the Activation of Mitochondrial Nitric Oxide Synthase and Citric Acid Cycle
    Biochimica et Biophysica Acta 1658 (2004) 64–71 www.bba-direct.com Review Role of calcium signaling in the activation of mitochondrial nitric oxide synthase and citric acid cycle Nathaniel Traaseth, Sarah Elfering, Joseph Solien, Virginia Haynes, Cecilia Giulivi* Departments of Chemistry and Biochemistry and Molecular Biology, University of Minnesota, 10 University Drive, Duluth, MN 55812, USA Received 18 February 2004; received in revised form 21 April 2004; accepted 26 April 2004 Available online 15 June 2004 Abstract An apparent discrepancy arises about the role of calcium on the rates of oxygen consumption by mitochondria: mitochondrial calcium increases the rate of oxygen consumption because of the activation of calcium-activated dehydrogenases, and by activating mitochondrial nitric oxide synthase (mtNOS), decreases the rates of oxygen consumption because nitric oxide is a competitive inhibitor of cytochrome oxidase. To this end, the rates of oxygen consumption and nitric oxide production were followed in isolated rat liver mitochondria in the G presence of either L-Arg (to sustain a mtNOS activity) or N -monomethyl-L-Arg (NMMA, a competitive inhibitor of mtNOS) under State 3 conditions. In the presence of NMMA, the rates of State 3 oxygen consumption exhibited a K0.5 of 0.16 AM intramitochondrial free calcium, agreeing with those required for the activation of the Krebs cycle. By plotting the difference between the rates of oxygen consumption in State 3 with L-Arg and with NMMA at various calcium concentrations, a K0.5 of 1.2 AM intramitochondrial free calcium was obtained, similar to the K0.5 (0.9 AM) of the dependence of the rate of nitric oxide production on calcium concentrations.
    [Show full text]