Ocean water
This presentation is the property of its rightful owner.
Sponsored Links
1 / 20

Ocean Water PowerPoint PPT Presentation


  • 43 Views
  • Uploaded on
  • Presentation posted in: General

Ocean Water. Salts and Gases. The Dissolving Power of Water. Dissolving power results from polar nature of H 2 O molecule. Na + and Cl - are held together by ionic bonds (attraction of opposite charges). H 2 O reduces the ionic bonding and pulls Na + and Cl - apart.

Download Presentation

Ocean Water

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Ocean water

Ocean Water

Salts and Gases


The dissolving power of water

The Dissolving Power of Water

  • Dissolving power results from polar nature of H2O molecule

  • Na+ and Cl- are held together by ionic bonds (attraction of opposite charges)

  • H2O reduces the ionic bonding and pulls Na+ and Cl- apart


Salinity in oceans

Salinity in Oceans

  • Salinity

  • Total amount of dissolved solids expressed in grams in 1 kg of water

  • Average salinity in oceans = 35 ‰

  • 35 parts per thousand (ppt)

  • 35 g/kg

  • Salinity variations

  • Due to differences in local rates of evaporation and precipitation (water budget)


Constituents of sea water

Constituents of Sea Water

  • Most abundant seawater elements are sodium (Na+) + chloride (Cl-)

  • Major constituents: SO42-,Mg2+, Ca2+, K+, and HCO3-

  • Minor and trace elements also present


Seawater versus river water

Seawater versus River Water


Salts in the ocean

Salts in the Ocean

Why is the ocean salty?

  • Salts come from:

  • Rocks = cations

  • Gases from mantle

  • Why is the ocean not getting saltier?

  • Salts going in = salts going out


Salts going out

Salts Going Out

  • Sea Sra

  • Sea Spray

  • Evaporites

  • Biological

    • Fecal pellets

    • Shell formation

  • Adsorption

  • Mid-ocean ridge magma


Principle of constant proportions

Principle of Constant Proportions

  • The amount of salt varies, but the relative proportions of ions are constant

  • Because of this principle, it is necessary to test for 1 salt ion (usually Cl) to determine total amount of salt present


Determining salinity

Determining Salinity

1. Calculating Salinity

  • Salinity=1.8065 x chlorinity (‰)

2. Salinometers

Cl-

Na+

  • Salinity determined by the electrical conductivity produced by dissolved salts

Deionized water

with salt


Factors affecting salinity

Factors Affecting Salinity

  • Precipitation

  • Evaporation

  • Run off

  • Freezing


Residence times

Residence Times

  • Average length in time that a substance remains in solution in seawater

  • Ions with longer residence times are most abundant in ocean


Effects of salinity

Effects of Salinity

  • Freezing point depression; boiling point elevation

  • Disrupts Hydrogen bonding

    (freezing point of seawater =-2°C)

2.Changes density

  • Pure water density = 1 kg/l

  • Seawater density = 1.024 kg/l

3. Changes vapor pressure

  • ↑ ‰, ↑ P


Desalination

Desalination

  • Fresh H20 from Salt H20

  • Methods

  • Distillation

  • Electrodialysis

  • Reverse Osmosis


Gases in seawater

Gases in Seawater

  • Major Gases: N2, O2 and CO2

  • O2 and CO2 important for life processes


Co 2 and o 2 with depth

CO2 and O2 with depth

  • Surface (0m)

  • Oxygen (O2) abundant gas

  • Photosynthesis dominant

  • ~ 200m - ~1,000m

  • Oxygen (O2) ↓

  • Carbon Dioxide (CO2) ↑

  • Respiration dominant

  • Organic matter decay

  • 1,000m – 4,000m

  • O2↑ slightly

  • Oxygenated bottom waters

  • Cold salty oxygenated H2O sinks in polar region transported to depth

  • CO2continues to ↑

  • Organic matter decay


Gases summary

GasesSummary

  • Photosynthesis

  • CO2 consumed; O2 produced

  • Therefore, O2 more abundant than CO2 in photic zone

  • Respiration

  • O2 consumed; CO2 produced

  • Organic matter (OM) decay

  • O2 consumed; CO2 produced

  • Respiration and OM decay

    • = ↑ CO2 below photic zone


The ph scale

The pH Scale

  • An acid has excess [H+] (Hydrogen ions)

  • A base has excess [OH-] (Hydroxyl ions)

  • CO2 controls acidity

  • ↑ CO2 = ↑ acidity

  • ↓ CO2 = ↓ acidity

pH of seawater = 7.5-8.5; Average = 7.8


Gases in seawater carbonate buffering system

Gases in SeawaterCarbonate Buffering System

  • Dissolved CO2 in water acts as a buffer

  • Prevents large shifts in pH

  • Seawater too basic:

    • H2CO3 HCO3- + H+ (pH drops)

  • Seawater too acidic:

    • HCO3- + H+ H2CO3 (pH rises)


Gas cycling

Gas Cycling

  • Photosynthesis produce O2

  • Respiration & decomposition of O.M. use O2

  • O.M. buried doesn’t consume all O2

  • Rocks consume O2

  • O2 Cycling

  • CO2 Cycling

  • Organisms use CO2 for tissue

  • Decay of organic matter releases CO2 back to ocean


Nutrients and organics

Nutrients and Organics

  • Required for plant growth

  • Cycled by plant growth and decay

  • Organics used by organism or buried


  • Login