Seawater constituent
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Transcript of Seawater constituent
Seawater
Earth is an Ocean Planet
Topics
• Origin of the Ocean and Atmosphere
• Hydrologic Cycle
• Biogeochemical Cycle
• Seawater Salinity
• Variations in Seawater Chemistry
• Carbonic Acid System
Topics
• Origin of the Ocean and Atmosphere
• Hydrologic Cycle
• Biogeochemical Cycle
• Seawater Salinity
• Variations in Seawater Chemistry
• Carbonic Acid System
Seawater Salinity
Seawater SalinityMajor Constituents, Minor Constituents, Trace
Elements, and Gases
Seawater is 96.5% H2O (solvent)
Seawater is 96.5% H2O (solvent)
3.5% dissolved constituents (solutes)
Seawater Constituents
Seawater Constituents
• Four categories of solutes:
Seawater Constituents
• Four categories of solutes:1. Major constituents
Seawater Constituents
• Four categories of solutes:1. Major constituents2. Minor constituents
Seawater Constituents
• Four categories of solutes:1. Major constituents2. Minor constituents3. Trace elements
Seawater Constituents
• Four categories of solutes:1. Major constituents2. Minor constituents3. Trace elements4. Gases
Salinity
Salinity
• Salinity of seawater is relatively uniform
Salinity
• Salinity of seawater is relatively uniform• Small changes are significant
Salinity
• Salinity of seawater is relatively uniform• Small changes are significant• Examples:
3.40%3.49%
Average Salinity
Average Salinity
• 3.5%
Average Salinity
• 3.5%
• 3.5 per cent
Average Salinity
• 3.5%
• 3.5 per cent
• 3.5 parts per hundred
Average Salinity
• 3.5%
• 3.5 per cent
• 3.5 parts per hundred
• 35‰
Average Salinity
• 3.5%
• 3.5 per cent
• 3.5 parts per hundred
• 35‰
• 35 per mil
Average Salinity
• 3.5%
• 3.5 per cent
• 3.5 parts per hundred
• 35‰
• 35 per mil
• 35 parts per thousand
Average Salinity
• 3.5%
• 3.5 per cent
• 3.5 parts per hundred
• 35‰
• 35 per mil
• 35 parts per thousand
35 ppt
Average Salinity
• 3.5%
• 3.5 per cent
• 3.5 parts per hundred
• 35‰
• 35 per mil
• 35 parts per thousand
35 ppt34.7 ppt
Major Constituents
Major Constituents
• Most seawater constituents are ions
Major Constituents
• Most seawater constituents are ions• e.g. Cl- and Na+
Major Constituents
• Most seawater constituents are ions• e.g. Cl- and Na+
• Six major constituents
Major Constituents
• Most seawater constituents are ions• e.g. Cl- and Na+
• Six major constituents• Constitute >99% of seawater salinity
Major Constituents
• Most seawater constituents are ions• e.g. Cl- and Na+
• Six major constituents• Constitute >99% of seawater salinity• Concentrations of the major constituents
determine the salinity of seawater
Major Constituents
Major Constituents
1. Cl-
Major Constituents
1. Cl-
2. Na+
Major Constituents
1. Cl-
2. Na+
3. SO42-
Major Constituents
1. Cl-
2. Na+
3. SO42-
4. Mg2+
Major Constituents
1. Cl-
2. Na+
3. SO42-
4. Mg2+
5. Ca2+
Major Constituents
1. Cl-
2. Na+
3. SO42-
4. Mg2+
5. Ca2+
6. K+
Major Constituents
1. Cl-
2. Na+
3. SO42-
4. Mg2+
5. Ca2+
6. K+
Salinity of Seawater
Major Constituents
Major Constituents
NaCl86%
Range of Salinity
Range of Salinity
• Salinity is relatively uniform - 35 ppt
Range of Salinity
• Salinity is relatively uniform - 35 ppt• Salinity varies (over a small range)
Range of Salinity
• Salinity is relatively uniform - 35 ppt• Salinity varies (over a small range)• General range of variation in the open
ocean is 33-37 ppt
Range of Salinity
• Salinity is relatively uniform - 35 ppt• Salinity varies (over a small range)• General range of variation in the open
ocean is 33-37 ppt
33 ppt - 37 ppt
Marcet’s Principle
Marcet’s Principle
• Despite small variations in seawater salinity, the relative proportions of the major constituents are constant
Marcet’s Principle
• Despite small variations in seawater salinity, the relative proportions of the major constituents are constant
• Also called the principle of constant proportions
Marcet’s Principle
Example of Marcet’s Principle:
Marcet’s Principle
• Station 1
Example of Marcet’s Principle:
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt
Example of Marcet’s Principle:
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = x
Example of Marcet’s Principle:
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = x• Mg/K = y
Example of Marcet’s Principle:
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = x• Mg/K = y• Ca/SO4 = z
Example of Marcet’s Principle:
Cl/Na
Cl/Na
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = 1.8• Mg/K = y• Ca/SO4 = z
Mg/K
Mg/K
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = 1.8• Mg/K = 3.4• Ca/SO4 = z
Ca/SO4
Ca/SO4
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = 1.8• Mg/K = 3.4• Ca/SO4 = 0.15
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = 1.8• Mg/K = 3.4• Ca/SO4 = 0.15
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = 1.8• Mg/K = 3.4• Ca/SO4 = 0.15
• Station 2
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = 1.8• Mg/K = 3.4• Ca/SO4 = 0.15
• Station 2• Salinity - 36.3 ppt
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = 1.8• Mg/K = 3.4• Ca/SO4 = 0.15
• Station 2• Salinity - 36.3 ppt• Cl/Na = 1.8
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = 1.8• Mg/K = 3.4• Ca/SO4 = 0.15
• Station 2• Salinity - 36.3 ppt• Cl/Na = 1.8• Mg/K = 3.4
Marcet’s Principle
• Station 1• Salinity - 33.9 ppt• Cl/Na = 1.8• Mg/K = 3.4• Ca/SO4 = 0.15
• Station 2• Salinity - 36.3 ppt• Cl/Na = 1.8• Mg/K = 3.4• Ca/SO4 = 0.15
Marcet’s Principle
Marcet’s Principle
• Despite small variations in seawater salinity, the relative proportions of the major constituents are constant
Marcet’s Principle
• Despite small variations in seawater salinity, the relative proportions of the major constituents are constant
• The principle of constant proportions
Determine Salinity
Determine Salinity
• Station 3: salinity = x
Determine Salinity
• Station 3: salinity = x• To determine the salinity at a location,
oceanographers need to know the concentrations of the major constituents
Determine Salinity
• Station 3: salinity = x• To determine the salinity at a location,
oceanographers need to know the concentrations of the major constituents
• Constitute >99% of seawater salinity
Determine Salinity
• Station 3: salinity = x• To determine the salinity at a location,
oceanographers need to know the concentrations of the major constituents
• Constitute >99% of seawater salinity• Concentrations of the major constituents
determine the salinity of seawater
Major Constituents
Question
Question
• Considering Marcet’s principle -
Question
• Considering Marcet’s principle -how many of the major constituents must be measured to determine the salinity of seawater?
Major Constituents
Determine Salinity
Determine Salinity
• Only need to measure the concentration of one major constituent
Determine Salinity
• Only need to measure the concentration of one major constituent
• Use Marcet’s principle to calculate the concentrations of the other constituents
Determine Salinity
• Only need to measure the concentration of one major constituent
• Use Marcet’s principle to calculate the concentrations of the other constituents
• Which major constituent generally is measured?
Determine Salinity
• Only need to measure the concentration of one major constituent
• Use Marcet’s principle to calculate the concentrations of the other constituents
• Which major constituent generally is measured?
• Cl-
Determine Salinity
Determine Salinity
• Measure the concentration of Cl-
Determine Salinity
• Measure the concentration of Cl-
• Cl- = 19.35 ppt
Determine Salinity
• Measure the concentration of Cl-
• Cl- = 19.35 ppt• Cl-/Na+ = 1.8
Determine Salinity
• Measure the concentration of Cl-
• Cl- = 19.35 ppt• Cl-/Na+ = 1.8• Na+/Cl- = 0.56
Determine Salinity
• Measure the concentration of Cl-
• Cl- = 19.35 ppt• Cl-/Na+ = 1.8• Na+/Cl- = 0.56• 19.35 x 0.56 = 10.8 ppt
Determine Salinity
• Measure the concentration of Cl-
• Cl- = 19.35 ppt• Cl-/Na+ = 1.8• Na+/Cl- = 0.56• 19.35 x 0.56 = 10.8 ppt
measure Cl-
calculate Na+
Determine Salinity
Determine Salinity
• Measure Cl-
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
• Mg2+/Cl- = 0.07
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
• Mg2+/Cl- = 0.07
• Ca2+/Cl- = 0.02
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
• Mg2+/Cl- = 0.07
• Ca2+/Cl- = 0.02
• K+/Cl- = 0.02
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
• Mg2+/Cl- = 0.07
• Ca2+/Cl- = 0.02
• K+/Cl- = 0.02
• 19.35 ppt
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
• Mg2+/Cl- = 0.07
• Ca2+/Cl- = 0.02
• K+/Cl- = 0.02
• 19.35 ppt
• 19.35 ppt x 0.56 = 10.8 ppt
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
• Mg2+/Cl- = 0.07
• Ca2+/Cl- = 0.02
• K+/Cl- = 0.02
• 19.35 ppt
• 19.35 ppt x 0.56 = 10.8 ppt
• 19.35 ppt x 0.14 = 2.7 ppt
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
• Mg2+/Cl- = 0.07
• Ca2+/Cl- = 0.02
• K+/Cl- = 0.02
• 19.35 ppt
• 19.35 ppt x 0.56 = 10.8 ppt
• 19.35 ppt x 0.14 = 2.7 ppt
• 19.35 ppt x 0.07 = 1.3 ppt
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
• Mg2+/Cl- = 0.07
• Ca2+/Cl- = 0.02
• K+/Cl- = 0.02
• 19.35 ppt
• 19.35 ppt x 0.56 = 10.8 ppt
• 19.35 ppt x 0.14 = 2.7 ppt
• 19.35 ppt x 0.07 = 1.3 ppt
• 19.35 ppt x 0.02 = 0.4 ppt
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
• Mg2+/Cl- = 0.07
• Ca2+/Cl- = 0.02
• K+/Cl- = 0.02
• 19.35 ppt
• 19.35 ppt x 0.56 = 10.8 ppt
• 19.35 ppt x 0.14 = 2.7 ppt
• 19.35 ppt x 0.07 = 1.3 ppt
• 19.35 ppt x 0.02 = 0.4 ppt
• 19.35 ppt x 0.02 = 0.4 ppt
Determine Salinity
• Measure Cl-
• Na+/Cl- = 0.56
• SO42-/Cl- = 0.14
• Mg2+/Cl- = 0.07
• Ca2+/Cl- = 0.02
• K+/Cl- = 0.02
• 19.35 ppt
• 19.35 ppt x 0.56 = 10.8 ppt
• 19.35 ppt x 0.14 = 2.7 ppt
• 19.35 ppt x 0.07 = 1.3 ppt
• 19.35 ppt x 0.02 = 0.4 ppt
• 19.35 ppt x 0.02 = 0.4 ppt
35.0 ppt
Determine Salinity
Determine Salinity
• To determine salinity within 1%, need to know the concentrations of only the major constituents
Determine Salinity
• To determine salinity within 1%, need to know the concentrations of only the major constituents
• Major constituents are >99% of salinity
Determine Salinity
• To determine salinity within 1%, need to know the concentrations of only the major constituents
• Major constituents are >99% of salinity• Only have to measure one major
constituents to determine salinity
Determine Salinity
• To determine salinity within 1%, need to know the concentrations of only the major constituents
• Major constituents are >99% of salinity• Only have to measure one major
constituents to determine salinity• Measure one constituent and calculate
the others using Marcet’s principle
Determine Salinity
• To determine salinity within 1%, need to know the concentrations of only the major constituents
• Major constituents are >99% of salinity• Only have to measure one major
constituents to determine salinity• Measure one constituent and calculate
the others using Marcet’s principle• Generally measure Cl-
Conservative Property
Conservative Property
• Concentrations of the major constituents are conservative properties of seawater
Conservative Property
• Concentrations of the major constituents are conservative properties of seawater
• Conservative properties are
Conservative Property
• Concentrations of the major constituents are conservative properties of seawater
• Conservative properties are1. altered primarily at the ocean’s surface
Conservative Property
• Concentrations of the major constituents are conservative properties of seawater
• Conservative properties are1. altered primarily at the ocean’s surface2. not significantly affected by biological activity
Change Salinity
• Salinity is altered primarily at the ocean’s surface by
Change Salinity
• Salinity is altered primarily at the ocean’s surface by
1. addition of water (precipitation)
Change Salinity
• Salinity is altered primarily at the ocean’s surface by
1. addition of water (precipitation)2. removal of water (evaporation)
Change Salinity
Explains Marcet’s Principle
Na+
Cl- Cl-
35 ppt
Cl-/Na+ = 1.8
Despite small variations in seawater salinity, the relative
proportions of the major constituents are constant
Na+
Cl- Cl-
35 ppt
Cl-/Na+ = 1.8
Na+
Cl- Cl-
Explains Marcet’s Principle
Na+
Cl- Cl-
35 ppt
Cl-/Na+ = 1.8
Na+
Cl- Cl-
Explains Marcet’s Principle
Na+
Cl- Cl-
35 ppt
Cl-/Na+ = 1.8
Na+
Cl- Cl-
37 ppt
Explains Marcet’s Principle
Na+
Cl- Cl-
35 ppt
Cl-/Na+ = 1.8
Na+
Cl- Cl-
37 ppt
Cl-/Na+ = 1.8
Explains Marcet’s Principle
Na+
Cl- Cl-
35 ppt
Cl-/Na+ = 1.8
Na+
Cl- Cl-
37 ppt
Cl-/Na+ = 1.8
Na+
Cl- Cl-
Explains Marcet’s Principle
Na+
Cl- Cl-
35 ppt
Cl-/Na+ = 1.8
Na+
Cl- Cl-
Na+
Cl- Cl-
37 ppt
Cl-/Na+ = 1.8
Explains Marcet’s Principle
Na+
Cl- Cl-
35 ppt
Cl-/Na+ = 1.8
Na+
Cl- Cl-
Na+
Cl- Cl-
37 ppt
Cl-/Na+ = 1.8
33 ppt
Explains Marcet’s Principle
Na+
Cl- Cl-
35 ppt
Cl-/Na+ = 1.8
Na+
Cl- Cl-
Na+
Cl- Cl-
37 ppt
Cl-/Na+ = 1.8
33 ppt
Cl-/Na+ = 1.8
Explains Marcet’s Principle
Uniformity of Salinity
• Why is salinity relatively uniform?
Uniformity of Salinity
• Why is salinity relatively uniform?a small open ocean range of 33-37 ppt
Uniformity of Salinity
• Why is salinity relatively uniform?a small open ocean range of 33-37 ppt
• Uniform because the ocean is well mixed
Uniformity of Salinity
• Why is salinity relatively uniform?a small open ocean range of 33-37 ppt
• Uniform because the ocean is well mixed• To explain how the ocean became well mixed,
oceanographers use the
Uniformity of Salinity
• Why is salinity relatively uniform?a small open ocean range of 33-37 ppt
• Uniform because the ocean is well mixed• To explain how the ocean became well mixed,
oceanographers use thelong residence times of the major constituents
Uniformity of Salinity
• Why is salinity relatively uniform?a small open ocean range of 33-37 ppt
• Uniform because the ocean is well mixed• To explain how the ocean became well mixed,
oceanographers use thelong residence times of the major constituentsshort mixing time of the ocean
Uniformity of Salinity
All of the major constituentshave residence times > 106 yr
Ocean Mixing pattern
Atlantic Indian Pacific
Ocean Mixing pattern
Atlantic Indian Pacific
Ocean Mixing pattern
Atlantic Indian Pacific
Ocean Mixing pattern
Atlantic Indian Pacific
Ocean Mixing pattern
Atlantic Indian Pacific
Ocean Mixing pattern
Atlantic Indian Pacific
Mixing time ≈ 1000 yr
Ocean Mixing pattern
Mixing time ≈ 1000 yr
Ocean Is Well Mixed
Ocean Is Well Mixed
• Residence times of the major constituents are much, much longer than the mixing time
Ocean Is Well Mixed
• Residence times of the major constituents are much, much longer than the mixing time
1,000,000 yr >>> 1,000 yr
Ocean Is Well Mixed
• Residence times of the major constituents are much, much longer than the mixing time
1,000,000 yr >>> 1,000 yr106 yr >>> 103 yr
Ocean Is Well Mixed
• Residence times of the major constituents are much, much longer than the mixing time
1,000,000 yr >>> 1,000 yr106 yr >>> 103 yr
• Residence time/mixing time = X
Ocean Is Well Mixed
• Residence times of the major constituents are much, much longer than the mixing time
1,000,000 yr >>> 1,000 yr106 yr >>> 103 yr
• Residence time/mixing time = X106 yr/103 yr = 103
Ocean Is Well Mixed
• Residence times of the major constituents are much, much longer than the mixing time
1,000,000 yr >>> 1,000 yr106 yr >>> 103 yr
• Residence time/mixing time = X106 yr/103 yr = 103
• In 1,000,000 yr, the ocean mixes itself 1000x
Minor Constituentsand Trace Elements
Minor Constituentsand Trace Elements
• Minor constituents measured in ppm
Minor Constituentsand Trace Elements
• Minor constituents measured in ppm• Trace elements measured in ppb or pptr
Minor Constituentsand Trace Elements
• Minor constituents measured in ppm• Trace elements measured in ppb or pptr• In general,
Minor Constituentsand Trace Elements
• Minor constituents measured in ppm• Trace elements measured in ppb or pptr• In general,
Marcet’s principle does not apply
Minor Constituentsand Trace Elements
• Minor constituents measured in ppm• Trace elements measured in ppb or pptr• In general,
Marcet’s principle does not applytend to be nonconservative
Minor Constituentsand Trace Elements
• Minor constituents measured in ppm• Trace elements measured in ppb or pptr• In general,
Marcet’s principle does not applytend to be nonconservativetend to have shorter residence times
Biolimiting Nutrients
Biolimiting Nutrients
• Primary biolimiting nutrients are in trace concentrations:
N, P, Si, Fe
Nutrient concentrations are low in the open ocean
Nutrient concentrations are low in the open ocean
Water is clear
Atmospheric Gases
Gases
Gases
• Atmospheric Gases
Gases
• Atmospheric Gases
N2 - 78%
Gases
• Atmospheric Gases
N2 - 78%
O2 - 21%
Gases
• Atmospheric Gases
N2 - 78%
O2 - 21%
CO2 - 0.035%
Gases
• Atmospheric Gases
N2 - 78%
O2 - 21%
CO2 - 0.035%
• Oceanic Gases
Gases
• Atmospheric Gases
N2 - 78%
O2 - 21%
CO2 - 0.035%
• Oceanic Gases
N2 - 48%
Gases
• Atmospheric Gases
N2 - 78%
O2 - 21%
CO2 - 0.035%
• Oceanic Gases
N2 - 48%
O2 - 36%
Gases
• Atmospheric Gases
N2 - 78%
O2 - 21%
CO2 - 0.035%
• Oceanic Gases
N2 - 48%
O2 - 36%
CO2 - 15%
Gases
Gases
• Are N2, O2, and CO2 conservative or nonconservative?
Gases
• Are N2, O2, and CO2 conservative or nonconservative?
• N2 is conservative
Gases
• Are N2, O2, and CO2 conservative or nonconservative?
• N2 is conservative• O2 is nonconservative
Gases
• Are N2, O2, and CO2 conservative or nonconservative?
• N2 is conservative• O2 is nonconservative• CO2 is nonconservative
Gases
• Are N2, O2, and CO2 conservative or nonconservative?
• N2 is conservative• O2 is nonconservative• CO2 is nonconservative
Both O2 and CO2 are strongly affected by biological activity
Gases
• Are N2, O2, and CO2 conservative or nonconservative?
• N2 is conservative• O2 is nonconservative• CO2 is nonconservative
Both O2 and CO2 are strongly affected by biological activityThe concentrations of O2 and CO2 are altered below the ocean’s surface
Banded Ironstone
Variations in Seawater Chemistry
Variations in Seawater Chemistry
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