Glacial atmospheric CO 2 lowering must be due to greater storage in ocean at equilibrium, atmospheric pCO 2 determined by Henry’s Law pCO 2 = [CO 2 ] /

Slides:

Advertisements

Similar presentations

Phase Diagram for Water

Advertisements

Strong Acids/ Bases Strong Acids more readily release H+ into water, they more fully dissociate H2SO4  2 H+ + SO42- Strong Bases more readily release.

Dissociation and pH Dissociation of weak acids/bases controlled by pH Knowing the total amount of S and pH, we can calculate activities of all species.

Water Science Electroneutrality, pH, Alkalinity, Acidity

ENVE 201 Environmental Engineering Chemistry 1 Alkalinity Dr. Aslıhan Kerç.

Solubility of CO2 and Carbonate Equilibrium

Carbon Dioxide Sources and Sinks: Respiration and Photosynthesis

1 Carbon Cycle 9 Carbon cycle is critically important to climate because it regulates the amount of CO 2 and CH 4 in the atmosphere. Carbon, like water,

Dissociation of H 2 O:H 2 O ↔ H + + OH - K w = a H+ a OH- a H2O Under dilute conditions: a i = [i] And a H2O = 1 Hence: K w = [H + ] [OH - ] At 25 o C.

Carbonate System and pH

EVPP 550 Waterscape Ecology and Management Professor R. Christian Jones Fall 2007.

Dissolution of calcite in sediments -- metabolic dissolution.

Class evaluations.

Solubility Products Consider the equilibrium that exists in a saturated solution of BaSO 4 in water: BaSO 4 (s) Ba 2+ (aq) + SO 4 2− (aq)

Introduction to Groundwater Chemistry October 04, 2010.

ANALYTICAL CHEMISTRY CHEM 3811 CHAPTER 12 DR. AUGUSTINE OFORI AGYEMAN Assistant professor of chemistry Department of natural sciences Clayton state university.

Karst Chemistry I. Definitions of concentration units Molality m = moles of solute per kilogram of solvent Molarity [x]= moles of solute per kilogram.

Lecture 2 - Major Ions in Sea Water Why do we care about the major ions? What is the composition of seawater? What defines Major Ions? What are their concentrations?

Carbonate System Alkalinity Lecture 21. TOTH TOTH is the total amount of component H +, rather than the total of the species H +. o Every species containing.

The Carbon Cycle The carbon cycle describes the exchange of carbon atoms between various reservoirs within the earth system. The carbon cycle is a geochemical.

1 Acid-base reactions and carbonate system. 2 Topics for this chapter Acid base reactions and their importance Acid base reactions and their importance.

Lecture 10: Ocean Carbonate Chemistry: Ocean Distributions Controls on Distributions What is the distribution of CO 2 added to the ocean? See Section 4.4.

Lecture 2 - Major Ions in Sea Water What is the composition of seawater? What defines Major Ions? What are their concentrations? What are their properties?

THE RELATIONSHIP BETWEEN H2CO3* AND HCO3-

Lecture 14. Charge balance Sum of positive charges = sum of negative charges In natural waters: [H + ]+2[Ca 2+ ]+2[Mg 2+ ]+[Na + ]+[K + ]=[HCO 3 - ]+2[CO.

Ocean Water Salts and Gases.

Lecture Goals To review how pH and alkalinity work.

Introduction: coccolithophores

Effects of global warming on the world’s oceans Ashley A. Emerson.

1 Chapter 7 Ocean Chemistry About solutions and mixtures A solution is made of two components, with uniform (meaning ‘the same everywhere’) molecular properties:

Seawater Chemistry 70% of the Earth is covered by ocean water!

Overview of Some Chemistry in Natural Waters Gases dissolve according to Henry’s law: K H =[X(aq)]/P X ; X=O 2, CO 2, H 2 S, SO 2, etc.  Oxidation-Reduction,

Chapter 16: Applications of Aqueous Equilibria Renee Y. Becker Valencia Community College 1.

Water Chemistry: pH. pH pH is the measure of hydrogen ions (H+) –Negative logarithm of the H+ concentration Higher the pH, the lower the H+ concentration.

Chemical and Physical Structures of the Ocean. Oceans and Temperature Ocean surface temperature strongly correlates with latitude because insolation,

Seawater Chemistry.

The Chemistry of Seawater An Introduction to the World’s Oceans Sverdrup et al. - Chapter Six - 8th Ed.

Class The Oceans More on the chemistry of the Oceans... DISSOLVED GASES IN SEA WATER Solubility of atmospheric gases Solubility of atmospheric gases.

Chapter 7 Activity and the Systematic Treatment of Equilibrium

Ocean Chemistry Unit 5.  The chemical properties of the ocean are important to understand because the marine environment supports the greatest abundance.

Regulation of [H + ] Acid-Base Physiology.. pH vs [H + ]

Shipwrecks, Corrosion and Conservation Summary Slides PART 4 – Jack Dengate.

The Carbon Cycle. Carbon Dioxide and Carbonate system Why is it important? 1. CO 2 regulates temperature of the planet 2. Important for life in the ocean.

General Chemistry Element –composed of atoms Nucleus –protons (+) and neutrons (0) Electrons (-)

Solubility Chapter 17. No only do acids and bases dissolve in aqueous solutions but so do ionic compounds –Many ionic compounds tend to be strong electrolytes.

The Carbon Cycle. Carbon Dioxide and Carbonate system Why is it important? 1. CO 2 regulates temperature of the planet 2. Important for life in the ocean.

Solubility Equilibria 16.6 AgCl (s) Ag + (aq) + Cl - (aq) K sp = [Ag + ][Cl - ]K sp is the solubility product constant MgF 2 (s) Mg 2+ (aq) + 2F - (aq)

The Carbon Cycle. Carbon Dioxide and Carbonate system Why is it important? 1. Regulates temperature of the planet 2. Important for life in the ocean 3.

PH and Chemical Equilibrium. Acid-base balance Water can separate to form ions H + and OH - In fresh water, these ions are equally balanced An imbalance.

Solubility Equilibria Solubility Product Constant, K sp Precipitation Complex Ions.

1 Basic Ocean Chemistry AOSC 620 Why do we care? Source of much food. Sink for much CO 2 and acids. Biodiversity. Great store and transport of heat. Source.

Anthropogenic CO 2 invasion. I. Anthropogenic CO 2 uptake.

Lecture 20. Equivalence Points Particularly simple relationships occur when the activities of two species are equal. These are determined by equilibrium.

Carbon cycle theme #1 The Earth’s carbon cycle has a stabilizing mechanism against sudden addition of CO 2 to the atmosphere – About 50% of carbon emission.

1.Acid-base review Carbonate system in seawater 2.Carbonate sediments Dissolution / preservation 3.Pore water evidence of respiration-driven dissolution.

The Carbon Cycle. Carbon Dioxide and Carbonate system Why is it important? 1. Regulates temperature of the planet 2. Important for life in the ocean 3.

Carbonate Solubility Solubility Dissolution mechanisms Dissolution rate expressions Saturation state in the ocean T, P, and CO 2 release In situ [CO 3.

Objectives: 1) Describe the importance of water to living systems 2) Explain how each of water’s properties relate to polarity and H-bonding.

Chemical & Physical Properties of SeaWater

Storing carbon dioxide Learning objectives:  Describe the factors determining the relative solubility of a solute in aqueous and non aqueous solvents.

Acid Base Disturbance and Strong Ion Difference Dr Rob Stephens Joint Intensive Care Symposium 17/18 June 2010.

1.Acid-base review Carbonate system in seawater 2.Carbonate sediments Dissolution / preservation 3.Pore water evidence of respiration-driven dissolution.

Seawater Chemical Properties. 2 / 33 Phases of Substances.

ENVR 403 Introduction to Environmental Chemistry

Buffers Complexation.

Carbon cycle theme The Earth’s carbon cycle has a stabilizing mechanism against sudden addition of CO2 to the atmosphere About 50% of carbon emission is.

Inorganic Carbon.

Composition of Seawater

Acid/Base Balance and Density

Global terrestrial carbon estimation map ecosystem extents

Presentation transcript:

Glacial atmospheric CO 2 lowering must be due to greater storage in ocean at equilibrium, atmospheric pCO 2 determined by Henry’s Law pCO 2 = [CO 2 ] / K 0 need mechanisms to lower [CO 2 ] or raise K 0 (solubility) Modern surface pCO 2 (Takahashi et al., 2002)

dissolved inorganic carbon (DIC):  CO 2 = [CO 2 ] + [HCO 3 - ] + [CO 3 2- ] ~1% ~90% ~10% where CO 2  CO 2 (aq) + H 2 CO 3 Therefore we can lower [CO 2 ] by: decreasing DIC shifting DIC equilibrium away from CO 2 (‘to right’) cooling (slightly influences K 1 & K 2 ) freshening (slightly influences K 1 & K 2 ) alkalinity:DIC change

Temperature & salinity (effects on K values only) LGM temperature (colder) CO 2 more soluble in cold waters (K 0  ) DIC also shifts away from CO 2 ([CO 2 ]  ) could account for -30 ppm LGM salinity (saltier) CO 2 less soluble in salty waters (K 0  ) DIC also shifts toward CO 2 ([CO 2 ]  ) could result in +10 ppmv (Takahashi et al., 2002)

Alkalinity:DIC ratio also affects the speciation of DIC (at constant T, S) Electroneutrality In any solution, the sum of cation charges must balance the sum of anion charges Conservative alkalinity Excess of conservative cations over conservative anions (conservative: no [ ] change with pH, T, or P) Alk =  (conserv. cation charges) -  (conserv. anion charges) = ([Na + ] + 2[Mg 2+ ] + 2[Ca 2+ ] + [K+]…) - ([Cl - ] + 2[SO 4 2- ]…)  2350  eq/kg

The conservative alkalinity excess positive charge is balanced primarily by non-conservative anions from three systems: DIC, boron, and water Alk  [HCO 3 - ] + 2[CO 3 2- ] + [B(OH) 4 - ] + [OH - ] – [H + ] carbonate alkborate alkwater alk DIC therefore shifts to right (away from CO 2 ) as conservative alkalinity increases, providing more negative charges

pH, DIC, and B systems ‘move together’ in terms of charge DIC buffers pH changes add strong acid: CO 2 forms, consuming H +, hindering pH drop DIC speciation and pH H + OH -

Conservative alkalinity and DIC together increase Alk/DIC: DIC shifts to right (pCO 2 drops) decrease Alk/DIC: DIC shifts to left (pCO 2 rises) add Alk/DIC at 1/1: very little change in DIC speciation CO 2 gas Invasion:  Alk:DIC Evasion:  Alk:DIC Organic matter Respiration:  Alk:DIC Photosynthesis:  Alk:DIC CaCO 3 Dissolution:  Alk:DIC 2:1 Formation:  Alk:DIC 2:1 IncreaseDecrease Lesser increaseLesser decrease

Takahashi et al. (2002) cold photosynthesis & stratification upwelling Organic matter Respiration:  Alk:DIC Photosynthesis:  Alk:DIC

Carbonate system parameters carbonate system can be reduced to four interdependent, measurable parameters: DIC alkalinity pCO 2 pH full characterization requires measurement of only two

Some useful approximations DIC  [HCO 3 - ] + [CO 3 2- ] Alk  carbonate alk = [HCO 3 - ] + 2[CO 3 2- ] Therefore: [HCO 3 - ]  2DIC – Alk [CO 3 2- ]  Alk – DIC And since: pCO 2 = K 2 [HCO 3 - ] 2 / K 0 K 1 [CO 3 2- ] It follows that: pCO 2  K 2 (2DIC – Alk) 2 / K 0 K 1 (Alk – DIC) Using average surface water values: 1% increase in DIC gives ~10% increase in pCO 2 1% increase in Alk gives ~10% decrease in pCO 2