Print version Updated: 23 February 2020 Lecture #18 Dissolved - - PowerPoint PPT Presentation

▶
print version
SMART_READER_LITE
LIVE PREVIEW

Print version Updated: 23 February 2020 Lecture #18 Dissolved - - PowerPoint PPT Presentation

Apr 04, 2023 129 likes •281 views

Print version Updated: 23 February 2020 Lecture #18 Dissolved Carbon Dioxide: Introduction (Stumm & Morgan, Chapt.4 ) Benjamin; Chapter 5.4 & 7 David Reckhow CEE 680 #18 1 An Aquatic Humic Structure Hydroxy Acid OH COOH

slide-1
SLIDE 1

Lecture #18 Dissolved Carbon Dioxide: Introduction

(Stumm & Morgan, Chapt.4 )

Benjamin; Chapter 5.4 & 7

David Reckhow CEE 680 #18 1

Updated: 23 February 2020

Print version

slide-2
SLIDE 2

David Reckhow CEE 680 #18 2

COOH O COOH COOH COOH HOOC HOOC HO OH COOH H3CO OH Hydroxy Acid Aromatic Dicarboxylic Acid Aromatic Acid Aliphatic Acid Aliphatic Dicarboxylic Acid Phenolic-OH HO

From Thurman, 1985

An Aquatic Humic “Structure”

slide-3
SLIDE 3

Titration of Humics

 Model for

aquatic humic substances

 Acetic acid +

phenol

David Reckhow CEE 680 #18 3

slide-4
SLIDE 4

Acid Neutralizing Capacity

 Net deficiency of protons

 with respect to a proton reference level

 when the reference level is H2CO3, the

ANC=Alkalinity  conservative, not affected by T or P  In a monoprotic system:

 [ANC] = [A-] + [OH-] - [H+] 

= CTα1 + [OH-] - [H+]

David Reckhow CEE 680 #18 4

[ ]

∫

= =

=

x f n f

dpH ANC β

slide-5
SLIDE 5

Dissolved Carbon Dioxide

 Importance

 regulating pH in natural waters, also source

  • f carbon for autotrophic organisms

 Sources

 volcanism, combustion, respiration,

weathering

 Sinks

 photosynthesis, precipitation

David Reckhow CEE 680 #18 5

CaCO3 (s) + CO2 + H2O ←→ Ca+2 + 2HCO3

  • Base

Acid

Hardness Alkalinity

slide-6
SLIDE 6

Major Forms of Carbon on Earth

David Reckhow CEE 680 #18 6

Source Mass, 10

15 Kg

Percent Geologic inorganic minerals 60,000 83% Geologic organic minerals

a

12,000 17% Oceanic inorganics 40 0.056 Atmosphere 0.7 0.00097 All life on earth 0.6 0.00083

Ray, Table 3.3, pg. 37

slide-7
SLIDE 7

Carbon Forms: Definitions

David Reckhow CEE 680 #18 7

CO2 = carbon dioxide (dissolved and gas) H2CO3 = carbonic acid (dissolved) HCO3

  • = bicarbonate (dissolved)

CO3

  • 2

= carbonate (dissolved) CaCO3 = calcium carbonate (mineral)

Inorganic Carbon Organic Carbon

C6H12O6 = glucose (a sugar) CH3COOH = acetic acid (a carboxylic acid)

slide-8
SLIDE 8

The Carbon Cycle

David Reckhow CEE 680 #18 8

Atmospheric CO2 Aqueous Carbonates Plant Organic-C Animal Organic-C Geologic carbonates Fossil fuel Organic-C Combustion Dissolution Precipitation Consumption After: Ray, Figure 3.9

slide-9
SLIDE 9

Global Carbon Dioxide

David Reckhow CEE 680 #18 9

Atmospheric carbon dioxide, ppm.

https://www.esrl.noaa.gov/gmd/ccgg/trends/

slide-10
SLIDE 10

TOC Trends in US Rivers

David Reckhow CEE 680 #18 10

Reckhow, Rees & Nusslein, 2006

slide-11
SLIDE 11

Lake Erie

David Reckhow CEE 680 #18 11

Total Organic Carbon levels from 2004 to 2011 in the Western Basin of Lake Erie (Baldwin Raw) and in treated water (Baldwin FE)

slide-12
SLIDE 12

Tri-state Region

David Reckhow CEE 680 #18 12

The Northeast Climate Change Report has projected increases in temperature of 8- 12ºF in winter and 6-14°F in summer based on the higher emissions scenario. In general a great annual rainfall is expected, with more high flow events in winter and spring, higher intensity storms and longer annual droughts in summer. This is projected to cause a loss of spruce, fir, hemlock, maple beech and birch, and a migration to a oak/hickory forest. There may be more complete export of agriculturally-applied nutrients. The loss

  • f hemlocks could speed up

decomposition and nutrient cycling in soils, increasing nitrate runoff into streams.

slide-13
SLIDE 13

To next lecture

David Reckhow CEE 680 #18 13