Vital Water Alice Newton University of Algarve Joint Master in Water and Coastal Management University of Bergen 2005-2006
Bibliography
Books :
Philip Ball 1999: H 2 O A biography of Water ISBN 0 75381 092 1
Peter H. Gleick 1993: Water in Crisis Oxford University Press
Open University course team 1997 : Seawater: its composition, properties and behaviour
Frank J. Millero 1996 : Chemical Oceanography, CRC Press
Bibliography 2
Web
United Nations Environment Program www.unep.org Vital Water Graphics
Global International Water Assessment www.giwa.net
Intergovernemntal Panel on Climate Change www.IPCC.org
Objectives
Vital water is an introductory lecture that relates both to integrated river basin management or integrated coastal zone management
It also links up with many other modules in the course
Requirements
No special skills are required for this lecture
A knowledge of basic inorganic and environmental chemistry is useful.
Programme
The constituents of water
The water molecule
Properties of water
The origin of water
The hydrological cycle
Composition of natural waters
Ice and glaciation
Water and life
Water the destroyer
Water and society, resources, uses and abuses
Learning outcomes
After completing this module you should know: that although water is a very common substance on Earth, it has strange properties and is a scarce resource
After completing this module you should be able to: Explain why water is so special and what some consequences are for water and coastal management
Other skills
Consult scientific literature and websites
The Constituents of Water… a little chemistry
Hydrogen (H )
Oxygen (O)
H 2 O is the basic unit of water
Ratio 2:1 is a consequence of the atomic structure
Hydrogen (H)
About ¾ of the mass of the Universe is Hydrogen!
H atom has 1 proton
H usually has no neutrons, so the atomic mass is 1
0.000015 % of H has 1 neutron, so atomic mass is 2 (1 proton + 1 neutron)
This isotope (different number of neutrons) is called “heavy” water, Deuterium, or Hydrogen-2
Oxygen (O)
O atom has 8 protons
Mass of O is about 16 x mass of H (different isotopes and neutons)
O can have 7, 8 , 9 or 10 neutrons
O is the third most abundant element in the Universe
(the second most abundant element in the Universe is Helium, relatively unreactive)
The Origin of H and O… a little cosmo-chemistry
Current scientific theory
Protons (H + ) formed a millionth of a second after Big Bang, T~ a trillion degrees
Nucleosynthesis started one hundredth of a second later (protons+neutrons), T~ three billion degrees
Hydrogen atoms form, T~ 4000 ° C
The Origin of H, O and Water
Gravity leads to formation of Galaxies and Stars Hans Bethe 1939
Elements (C-N- O) formed in stars by fusion
Mainly generates 15 O but also 16 O 17 O Burbridge,Burbridge, Fowler and Hoyle 1957
Water formed by reaction of H and O
From “Element” to compound
Water classically was thought of as an Element
Lavoisiers’ experiments 1784 prove that water is formed by burning Hydrogen in the presence of oxygen. Hydrogen means “water former”
Nicholson and Carlisle split water by electrolysis to form hydrogen and oxygen
Berzelius recognized the fixed ratios H=2, O=1
Water as a Liquid
Liquid water
At present most of the water on Earth is in the liquid phase
Most liquid water (~97%) is in seawater
Water is the main component (~96%) of seawater
The Water Molecule
Hydrogen (H) and Oxygen (O)
H 2 O is the basic unit of water
Ratio 2:1
Consequence of atomic and molecular structure
Molecular Structure of Water
Hydrogen atoms have a partial positive charge.
Oxygen has 2 unbonded pairs of electrons with partial negative charges.
Tetrahedral, distorted by charges to minimize repulsion
Molecular structure is "bent" to yield a 104.5° angle between the hydrogen atoms instead of 109.5° for a regular tetrahedron .
Hydrogen bonds
A partly positive hydrogen atom of one water molecule attracts the partly negative unbonded electron pair in the oxygen atom, forming a hydrogen bond.
Hydrogen bonds
The oxygen atom of a water molecule is the hydrogen bond acceptor for two hydrogen atoms .
Each O-H group serves as a hydrogen bond donor.
4 Hydrogen bonds
Leads to the formation of 4 hydrogen bonds by water
The tetrahedral structure of the water hydrogen bonds is a consequence of the sp3 hybridization of the oxygen's electrons.
The two hydrogen bonds between the oxygen and the hydrogen atoms on another water molecule utilize the two partly-negative pairs of unbonded electrons on oxygen.
Structure of liquid water
The hydrogen bonding pattern of water is more irregular than that of ice.
The absolute structure of liquid water has not been determined .
Many theories e.g. Frank and Wen flickering cluster model : as a liquid, water has partly crystalline “clusters” but some “loose molecules”
Properties of Water The Strange Liquid
Density anomaly
Most substances are denser in the solid than in the liquid phase
The structure of ice at 0 o C is less dense than that of liquid water at 0 o C because ice has a more rigid lattice.
Density maximum at 4 o C
Ice forms at surface and floats
Enormous implications for climate
High Specific Heat Capacity
Very high energy required to change the temperature of water
Water is slow to heat and slow to cool
Warm ocean currents can therefore transport huge amounts of heat
Gulf Stream transports more heat daily than would be produced by burning global quantity of coal mined annually
Latent Heat Capacity
Energy to change phase without changing temperature
When water is heated to 100ºC, is doesn’t all instantly evaporate to steam. A lot of heat has to be supplied to transform all the liquid into vapour.
When ice is reaches 0ºC, is doesn’t all instantly melt. A lot more heat must be applied to transform all the ice into liquid water
Specific Heat and Latent Heat Heat Energy Supplied 100 ºC 0 ºC T ºC Boiling Point Freezing Point Specific Heat of Water Specific Heat of Ice Latent Heat of Water Latent Heat of Ice
Phase transitions solid-liquid-gas
Boundaries of phases are controlled by temperature and pressure
Phase diagram plots phases on a graph of temperature and pressure
T P
Phase diagram of water
Triple Point
Solid, Liquid and Gas phases can co-exist
Below Triple Point , solid sublimes to gas
Gas and Solid extend throughout T and P
Liquid is a “contigent” state, not always necessary
Critical Point
Boundary between Liquid and Solid stops at Critical Point
Supercritical region: gas and liquid behave in same way
Gas and Liquid are both Fluids phases
More anomalous properties
Excellent solvent , especially of ionic compounds
Highly reactive and therefore corrosive
Viscosity increases with pressure
High boiling point and freezing point
Low dissociation, but can act as an Acid or Alkali and is an electrolyte
Water as Ice
Molecular structure of ice
Water molecules in ice form an open hexagonal lattice in which every water molecule is hydrogen bonded to four others.
The geometric regularity of these hydrogen bonds contributes to the strength of the ice crystal.
All hydrogen bonds are satisfied in ice.
Structure of Ice I “ normal” ice
“ Normal” ice
Ice I has hexagonal symmetry that we associate with snowflakes
Dendritic ( branching ) growth from a “seed” particle
Many types of ice
Under pressure, Ice I can change to other forms e.g. ice II and ice III.
1998 Ice XII was discovered!
Some forms are very unstable e.g. ice IV and ice XII
I-V the hexagonal lattice is buckled
VI-XII several interlocking lattices
“ Weird” ice
At ~ 3500 atm, Ice I can change to other forms e.g. ice II and ice III.
Ice VI will remain solid up to 80ºC, but melts at pressures less than 6500 atm !
Ice VII is formed at 22000 atm, is twice as dense as ice I and melts at 100 ºC !
Ice IX cannot exist at temperatures above -100 ºC !
Amorphous, glassy ice
Low density amophous ice forms by rapid freezing to -140 ºC
There is no “time” to form the lattice
Can only exist between -140 ºC and -120 ºC
Behaves like very viscous liquid
High density amorphous ice is formed from ice I at 10 000 atm and -196 ºC
Supercooled water
Liquid water can also be supercooled
High altitude, low temperatures and pressures e.g. cirrus clouds ~38 ºC
Solutes also decrease the freezing point, e.g. seawater freezes at – 1.9 ºC
Where did the water on Earth come from?
Water in the Universe
“ Excited” molecules of water radiate MASERS (Microwave Amplified Stimulated Emission of Radiation)
Water is
common in
the Universe
e.g. Orion’s
Horse Head
Nebula
Townes 1969
Solar Systems
Material orbiting stars can form a planetary solar system (such as ours)
Our solar system consists of
Inner “rock” planets e.g. Earth and Mars
Outer “gas” planets e.g. Jupiter and Saturn
Planetesimals such as asteroids, meteorites and comets that maybe rich in water, CO 2 and NH 3
Our Solar System
Water in our Solar System
Carbonaceous Chondrites (type of meteorite) contain 20% water as ice or in the structure of consitutent minerals
Common meterorites (Chondrites) contain 0.1% water
Comets contain huge amounts of water, typically one thousand trillion kgs!
e.g. Halley’s Comet
Size 8km x 16km
Mass 100 trillion Kg
Mostly ice
Origins of Water on Planet Earth
Collisions with Planetesimals such as asteroids, meteorites and comets brought water, CO 2 and NH 3 to the Earth
Formation of Lithosphere
As Earth cooled, a rocky surface, the lithosphere, formed on the molten magma
Formation of early Atmosphere
Cooling magma released volatiles by degassing to form early atmosphere
Early atmosphere was mainly CO 2 , N 2 and water vapour
Formation of Hydrosphere
Between 4.4 and 4.0 billion years ago
Temperature low enough for condensation of water
Formation of clouds and rain
Formation of oceans
The Blue Planet
Water controls our Planet
Geological change : erosion by rivers, glaciers and coastal erosion
Short term climate : El Niño, North Atlantic Oscillation
Climate change : Ice-ages
El Niño
El Niño mechanism http://www.pmel.noaa.gov/tao/elnino/nino-home.html#
Some facts and figures…
Planet Water would be more appropriate as a name than planet Earth!
More than 2/3 of planet surface is water
More than 1/20 of planet surface is ice
Only tiny proportion, 1/10000, is freshwater
The Hydrological Cycle
Hydrological cycle
Very dynamic cycling, main mechanisms are evaporation and condensation / precipitation
Balance between water in 3 states : solid, liquid, gas; ice, water and vapour
Hydrological cycle regulates and controls many other biogeochemical cycles
Water in the Sky… Clouds
Volume equal to all the oceans passes through atmosphere ~3100 years
Atmosphere only contains about 0.001% of total water at any one time as clouds
Represents only 0.035% of all freshwater
Equivalent to about 2.5 cm of rain over all surface of globe
Formation of Clouds
Process of condensation
Condensation nuclei
Airborne particles e.g.
dust,
soot,
DMS
Dimethyl Sulphide (DMS)
Produced by phytoplankton
In atmosphere forms sulphate
Coalesces with sodium and magnesium ions from sea-salt
Forms crystalline particles that are condensation nuclei
Clouds
Cumulus
Stratus
Alto-cumulus
Alto-stratus
Cirrus
Cumulo-nimbus
Cumulus
low altitude
formed by convection of air
“ warm clouds“ mostly above 0ºC
fluffy and billowing
Image ID: wea00079, Historic NWS Collection Photo Date: September 1980 Photographer: Ralph F. Kresge #1126
Stratus
low altitude,
formed by convection of air meeting a stable layer
mostly above 0ºC
static
typical of overcast sky
Image ID: wea02051, Historic NWS Collection Location: Oahu, Hawaii Photo Date: March, 1976 Photographer: Ralph F. Kresge
Alto-cumulus
At higher altitudes
Formed at a lower temperature (0 to -39ºC)
Also Alto-stratus
Image ID: wea00039, Historic NWS Collection Photographer: Ralph F. Kresge #1201
Cirrus
high altitude
temperature below -39ºC
feathery
Image ID: wea00062, Historic NWS Collection Location: Looking SSW at Rossmoor, Maryland Photo Date: 10:45 A.M., January 29, 1976 Photographer: Ralph F. Kresge
Alto-stratus
At higher altitudes
formed at a lower temperature (0 to -39ºC)
Cumulo-nimbus
cumulus topped by cirrus
storm cloud
Image ID: wea00094, Historic NWS Collection Location: Mauna Kea, Hawaii Photo Date: February 1976 Photographer: Ralph F. Kresge #0221
Water Vapour and Global Change
Water vapour is a greenhouse gas
Global warning may cause positive feedback : warming puts more water-vapour into atmosphere which causes further warming
Alternately more water-vapour into atmosphere may cause more, violent precipitation
Also consider albedo effect versus greenhouse effect
Evaporation and Transpiration
~ 875 cubic km of water evaporate from the oceans every day
Equivalent to about 1m of the oceans annually
~ 160 cubic km of water evaporate from land and plants ( transpiration ) every day
Residence times
Biospheric water
Atmospheric water
River channels
Swamps
Lakes and reservoirs
Soil moisture
Ice caps and glaciers
Ocean and seas
Groundwater
1 week
1.5 weeks
2 weeks
1-10 years
10 years
2 weeks-1 year
1000-100 000 years
4000 years
2 weeks-10 000 years
Runoff
Precipitation on land - Evaporation on land = Runoff
~100 cubic km per day
Deserts: precipitation = evaporation
Amazon:
precipitation >> evaporation
1/5 of freshwater input into oceans
Oceans and Seas are all interconnected basins
Atlantic
Pacific
Indian
Southern (Antarctic)
2/3 in South Hemisphere
Mediterranean Sea
Black Sea
North Sea
Red Sea
Arabian Sea
East and South China Seas
Arctic
Oceans … a little oceanography
½ of the globe is 3 000-6 000m deep!
Ocean trenches reach 11 000m, mountains only 8000m
Mid-ocean ridges are the greatest mountain chains
Topography of Ocean Basins
Surface Currents
wind
rotation (gyres)
N. Equatorial
S. Equatorial
West wind drift
Norway
North Atlantic
Canary
Brazil
Agulhas
Alaska
Oyashio
Kuroshio
Peru
Global Ocean Surface Currents http://web.uvic.ca/~rdewey/eos110/webimages.html
Deep Circulation, Global Conveyor
thermohaline
Density driven
(T and S)
http://web.uvic.ca/~rdewey/eos110/webimages.html
Tidal currents
Up to 14m!
Gravitational pull (moon + sun)
24 h and 50 min cycle
Semi diurnal (High-Low-High-Low)
Lunar cycle (Spring-Neap-Spring-Neap)
River basins
Nile
Length: 6650 km
Catchment: ~ 3 million km 2
Amazon
Length: 6450 km
Catchment:
~ 7 million km 2
Volume of water transported
Different climatic regions ( e.g. Nile and Amazon)
Dams
Aswan: Lake Nasser 500km, +900 000 acres of arable land, ¼ of Egypt’s power
Itaipu
Three gorges estimate 18200 megawatts, reservoir ~660 km long
Aswan Dam Lake Nasser
River basins
Different geomorphology
Different size of flood plains
Erosion of rocks
Sediment transport
Dams
Groundwater
Some rain permeates through ground ( aquifer ) until it reaches impermeable bedrock or clay.
Upper limit is water table
Groundwater quality
Depends on rocks of aquifer
Hard water: chalk and limestone
Soft water: slate and granite
Mineral water: high concentration of dissolved minerals. Maybe volcanically heated, thermal.
Maybe contaminated by pesticides, fertilizers from agriculture or leachates from landfills
Characterization of Water by Mineral Composition … a little hydrochemistry
Ca 2+
Rain is acidic (~pH 5.5)
Dissolves carboniferous rocks Ca CO 3
Temperature is important ( solubility decreases with increasing temperature)
K= [Ca 2+ ] [CO 3 2- ] = 10 -8,3
(1:1)
P CO2 in soil < a P CO2 in the atmos ( P CO2 in soil ≈ 3 x 10 -4 atm.)
K= [Ca 2+ ] [HCO 3 - ] 2 = 10 -5,8 P CO2
(1:2)
Bicarbonate HCO 3 -
H 2 CO 3 Equilibrium
Controlled by pH
Normally HCO 3 - is dominant specie
Determine alkalinity of water
How do we represent the composition of water?
Bar charts or Collins diagram
Pie charts
Kite or stiff diagrams
Radial diagrams
Triangular or Piper diagrams
Semi-logarithmic or Schoeller diagrams
Exploitation of aquifers
Over exploitation may cause land subsidence e.g. London and Mexico
In coastal regions, seawater intrusion
Ice… the cryosphere
Ice Ages
Thought to be caused by astronomical variations called Milankovitch cycles
Obliquity
Precession
Eccentricity
Milankovitch cycles
The ice ages were due to the so-called Milankovitch cycles, that is a combination of the Earths eccentricity (the difference in distance to the sun throughout the year), the tilt of the Earth relative to the Earth-sun plane (difference summer – winter) and the time of the year when the Earth is closest to the sun.
Milutin Milankovitch
The 3 Milankovitch cycles
Precession : Orientation of the rotation axis with respect to Sun, 20 000 year cycle
Obliquity : tilt of rotation axis currently at 23.5º to plane of orbit, 40 000 year cycle
Eccentricity : elliptical shape of orbit, 100 000 year cycle
Precession
Orientation of the rotation axis with respect to Sun 20 000 year cycle
Obliquity : tilt of rotation axis currently at 23.5º to plane of orbit 40 000 year cycle Eccentricity : elliptical shape of orbit, 100 000 year cycle
Last Ice Age
18 000 years ago
Sea-level 120 m below present
Water bound up as continental icesheets
Laurentide ice sheet of N.America
Fennoscandinavian ice sheet of N.Europe
Present Occurrence of Ice
Water bound up in ice as:
Continental icesheets
Sea ice: iceshelves or pack-ice and icebergs
Mountain glaciers
Present cryosphere
Includes permafrost in tundra and snow at high altitudes
2% of total water volume
¾ of Earth’s freshwater
5.7% of surface of globe (seasonal fluctuations)
Most ice is stored in Antarctica
High albedo
Antarctic Icesheets and ice-shelves
Mean thickness 2100m
Maximum thickness 4800m
East Antarctic icesheet is larger than West Antarctic icesheet
East Antarctic icesheet on bedrock above sea level
West Antarctic icesheet on rock below sealevel
Also Ross and Ronne ice-shelves over sea
Ice cores
Icesheets are maintained by application of new coats of ice compressing previous layers
East Antarctic icesheet at 3000m is 250 000 years old
Analysis of cores of polar ice reveal previous composition of atmosphere
Greenland Plateau and Vostok, Antarctica Ice plateau on Greenland Vostok
Antarctic temperatures – during the last 400 000 years
Last four ice ages recorded in Antarctica http://www.grida.no/climate/ipcc_tar/wg1/fig2-22.htm
Icestreams and Icebergs
Melting of icesheets
can form icestreams
or icebergs
Mountain Glaciers
Frozen rivers
Flow slowly down with gravity
Glacial features
U-shaped valleys
Truncated spurs
Hanging valleys
Moraines
Fjords
Glacier melt water
Discharged into rivers, or directly into sea at high latitudes
Cryosphere and global change
Seasonal glacial retreat
Retreat over several years maybe symptom of global change and warming
Increase number of icebergs in N. Atlantic
Decrease thickness of pack-ice in Arctic
Glacier retreat
The Nigard valley. The picture shows the retreat of the glacier. Photo: Bjørn Wold, NVE.
Changes in sea-ice thickness in the Arctic United Nations Environment Programme (UNEP) –Grid Arendal Overall change -1.3 m (40%) Positions with comparison USS Archerfish Measurements ’60s and ’90s
The destructive forces of Water
Floods
River floods and ice jams
Coastal floods
Hurricanes and cyclones
Tsunamis
Floods and mortalities
40% of deaths from natural disasters are due to floods
1965-85 half of Federal disasters in USA due to floods
Hurricane Agnes: 3.5 billion US, 120 lives
In USA, floods cost 2-4 Billion US dollars annually and about 200 lives
Figures much higher in some other parts of world
River floods
1992 Pakistan and India: 2000 lives
China: 2297 BC
1332 AD 7 000 000 lives
1887 6 000 000 lives
Bangladesh: Ganges, Bramaputra and Megna rivers, low elevation frequent floods
Egypt: historical flooding of Nile
1993 Mississipi flood: 15 billion U$ 487 lives
Ice jams and melts
1936 New England: 107 lives
Coastal floods
High tides and storm surges 1953 North Sea
Tropical cyclones
Hurricanes (Caribbean)
Typhoons (W. Pacific)
Tsunami
Hurricanes
1900 Galveston 10 000 lives
Hugo 1989 and Andrew 1992 30 billion US dollars
Formed over warm seas
Hurricane Hugo http://www.photolib.noaa.gov/historic/nws/hugo1.html Digitized Charleston WSR-57 radar image of Hugo with superimposed winds Real-time winds measured onboard NOAA research aircraft flying into Hugo Wind velocity transmitted to NHC through a satellite link as eyewall hit coast Sustained winds of 155 mph at 10,000 feet and 135 mph at surface Higher gusts were estimated in area of landfall Image ID: wea00455, Historic NWS Collection Photographer: Dr. Frank Marks, AOML Hurricane Research Division
Hurricane Andrew http://www.photolib.noaa.gov/historic/nws/andy1.html Hurricane Andrew - visible satellite image taken by METEOSAT 3 This picture depicts Andrew during period of maximum intensity over Bahamas August 23,1992 Image ID: wea00520, Historic NWS Collection
Scientists' Fears Come True as Hurricane Floods New Orleans
John Travis
Katrina held few surprises for hurricane experts, who have repeatedly warned about the potential catastrophic consequences for New Orleans if such a storm were to make landfall nearby.
Lake Pontchartrain and New Orleans
New Orleans flooded
Breeched Levee
Breeched Levee
Loss of Wetlands An ambitious $14 billion plan known as Coast 2050 attempts to protect more than 10,000 square kilometers of Louisiana's wetlands, which are disappearing at a rate of up to 90 square kilometers per year, one of the highest rates of land loss in the world. But a number of unanswered scientific questions swirl around the plan. And it could run afoul of powerful interests in the shipping, petroleum, and fishing industries. Louisiana's Vanishing Wetlands: Going, Going ... Joel Bourne Science 2000 290: 456. (in Letters) [Full Text]
Altered Delta
Tropical cyclones in Indian Ocean
Bangladesh: large areas only 3m altitude
1737: 1 000 000 lives
1876
1970: 200 000 lives
1991: 100 000 lives
The 1998 flood in Bangladesh
Floods in Bangladesh
Tsunami
caused by:
Earthquakes and Sea-floor displacement : e.g. 26 December 2004 Aceh
Landslides : e.g. Alaska 1957
Volcanoes : e.g. Krakatau 1883
Tsunami
1792 Japan: 15 000 lives
1896 Japan: 27 000 lives
1957 Alaska: wave 60m devasted trees upland to 530m
1883 Krakatau: 36 000 lives
2004 Aceh and Indian Ocean: 300 000+ lives
26 December 2004 off Aceh, Indonesia
Indonesia: lhoknga_iko_2004364
Sri Lanka_qbd_2004361
Sea Level Change
Linked to climate change and ice ages
Last ice age, sea level 120m below present
Still enough ice in ice-sheets and glaciers to raise sea level by 66m!
A rise of only 5m would be catastrophic for Pacific Islands, Bangladesh, the Netherlands, Vietnam, Florida
Current estimates vary 20cm-1m by 2100
Thermal expansion is main cause of rise
Water and Society
Religions: water Gods, creation, floods
Ceremonies: baptism, cleansing before worship, sacred and holy water
Ancient Civilizations and Waterways
Mesopotamia
India
China
Egypt
Tigris and Euphates
Ganges
Yellow River
Nile
Water and Health
Cholera
Typhoid
Dysentry
Hepatitis A
Maleria and other mosquito-borne diseases (Dengue, West Nile fever)
Water as a Resource
The uses of water
Domestic
Drinking
Hygiene
Cleaning
Industrial
Heavy industry
Light industry
Food industry
Power generation
Recreation
Bathing
Sailing
Agricultural
Irrigation
Aquaculture
Fisheries
Water and Energy
Hydroelectric power
Water as a “fuel” by splitting
Electolysis,
Photolysis,
Photosynthesis
H-O fuel cells
Tidal mills and barrages
Ocean currents
Water as a scarce resource
Uneven distribution of rainfall
2/3 of rainfall flows to sea
Global use of water
Tripled between 1950-90
Half of available runoff used by 1996
Use of water by sector differs
Use of domestic water differs…
Uganda and Burundi 5-25 Liters per day per person
Europe 100 to 260 liters per day per person
USA 400-500 liters per day
Same water quality for brushing teeth, flushing toilet and washing car
Agriculture
Most increases in crop production due to irrigation
Increasing water stress
Abuses of water
Wastage in distribution, leaks e.g. UK
Inefficient irrigation e.g. Middle East
Over extraction and salinization e.g. Mediterranean
Desertification e.g. MidWest dust bowl Sahel
Pollution
Pollution
Drinking water can be affected
Pesticides, Herbicides, Fungicides
Fertilizers
Industrial PCBs (paints, plastics, adhesives)
Metals from mines and industry
Hydrocarbons and Crude oil
Sewage pathogens
Organic Matter
Detergents
Acid rain
New or recycled water
Recycle grey water for agriculture
Desalination
Shipping water from countries where it is abundant e.g. Alaska to China, Norway to S. Europe
The Global International Waters Assessment
GIWA
Comprehensive strategic assessment
Designed to identify priorities for remedial and mitigatory actions in international waters.
GIWA's assessment tools Incorporate 5 major environmental concerns and application of the DPSIR framework.
DPSIR framework
Driving forces
Pressures
Impacts
State
Responses
Black Sea,
Amazon,
Gr. Barrier Reef,
Agulhas Current
GIWA Case Studies
Water and Life
Carbon life-forms…
All known life-forms are C-based
Many other elements essential for organic (C) life, e.g. N, P
All known life-forms also require water
Many organisms more than 70% water, some more than 90%
Humans require min. 1 liter per day
The Beginning of Life
~3.8 billion years ago.
Atmosphere contained N, CO 2 and water as well as H 2 S and CH 4 from volcanoes
Very little oxygen, anoxic, reducing
Current scientific theory: first life-forms were aquatic in shallow lagoons, or hydrothermal vents
Early life forms
Oldest fossils:
Rocks in SW Greenland
Australian Stromatolites 3.5 billion years
First life-forms:
anaerobic heterotrophs using simple organic molecules available by glycolysis or fermentation
chemosynthetic autotrophs using H 2 S
photosynthetic autotrophs using H 2 S
Oxygen and early life-forms
Oxygen produced by one type of photosynthesis
Uses H 2 O as a proton donor instead of H 2 S
Oxygen is oxidating, reactive, corrosive gas
Oxygen is TOXIC to aerobic life-forms
Oxygen accumulated slowly in the atmosphere
Permited the evolution of facultative anerobes and aerobic heterotrophs and
Aerobic respiration is far more energetic than fermentation
Aquatic life-forms
Aquatic life-forms usually restricted in their distribution to fresh or salt water
Osmotic pressure one of the colligative properties of water
Special adaptations needed for estuarine organisms to survive salinity changes and migratory organisms such as eels and salmon
Terrestrial plant-forms
Photosynthetic cyanobacteria probably first organisms to survive on land
460 million years ago bryophytes (mosses and liverworts) and ferns
325 million years ago tropical forests
Vascular plants “higher” supported by water-based fluids xylem and phloem
Depend on properties of water such as osmosis and capillary action
Transpiration from plants is important in Hydrological cycle
Terrestrial animal-forms
Many land-based animals need special adaptations to live out of water such e.g.
Molluscs such as gastropod snails
Crustacea such as crabs
Amphibians first vertebrates on land
Animals also have many water based fluids such as cytoplasm, blood plasma and lymph
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