Pidwirny, 2004
Peixoto and Kettani, 1973
Source: Natural Resources Canada
Percentage of Population with Access
to Water Supply Services
Solutions for Depletion: Desalination
• Desalinization
removal of salt from seawater to create freshwater
• Perfecting this technology would mean the oceans
could provide us with unlimited freshwater.
• Most of the world’s 7,500 desalination plants are
in wealthy oil states of the Middle East, where
water is scarce enough to make desalination
economically feasible.
How we Use Water
• Consumptive use
water is removed from an aquifer or surface body, and not
returned (most agricultural, industrial, and some
residential use)
• Nonconsumptive use = removal of water is only
temporary (passing water through a hydroelectric dam)
Agricultural Water Use
• Agriculture = 87% of world’s consumptive use of water
• Global consumption has risen in tandem with irrigation.
Disappearance of the Aral Sea
(Kazakhstan and Uzbekistan)
The Aral Sea was once the
fourth largest freshwater body
in the world, but has all but
disappeared
Groundwater Extraction
• 1 in 3 humans relies on groundwater for drinking.
• 99% of the rural U.S. & much of Canada relies on
groundwater for drinking.
• Extraction from aquifers is increasing, especially in
developing nations whose agriculture intensified with
green revolution.
Aquifers
• Aquifer = a porous spongelike layer of rock, sand, or
gravel that holds groundwater
• Confined or artesian aquifer = water under pressure,
trapped within impermeable layers (often clay)
• Unconfined aquifer = water under less pressure; no
overlying impermeable layer
• Aquifer recharge zone = geographic area where water
infiltrates soil and recharges aquifer.
Groundwater and Aquifers
Impacts of Water Mining
• When water is mined, ground may suddenly
collapse in sinkholes.
Other impacts:
Slow subsidence
(Venice, Mexico
City)
Saltwater intrusion
into drinking water
Wetland destruction
Figure 14.14
Surface Diversion
• Colorado River
water is heavily
diverted today
from a series of
dams, mostly
for agriculture.
Are the Great
Lakes next?
Flood control
• We build dikes and levees to prevent floods when river
levels rise.
• Flood control has saved many towns and crops from ruin.
• But long term, flood control can be self-defeating:
• Forces floodwater to stay in channel, creating risk of
catastrophic overflow, rising river base due to deposition or
dike break downstream
• Deprives farmland of nutrients that floods bring; decreases
soil productivity
Dams
• We build dams blocking the flow of rivers in order to:
–•Prevent floods
–•Generate electricity
–•Provide drinking water
–•Provide irrigation
• 45,000 dams over 15 meters high have been built in the
world.
• Few major rivers today are not dammed.
Benefits and costs of dams
Figure 14.11
Sedimentation and burial of
archaeological sites are
cited by critics
Photo: Greg Baker, Guardian
Precipitation
Glaciers
Groundwater
Surface water
• Most intensively farmed and
irrigated region in Canada
• 1/3 of the province’s sales of
agricultural products
•90 % of all water in the Oldman
and its tributaries to irrigated
agriculture
•food processing becoming bigger
industry - requires high quality water
resources
•City of Lethbridge growing quickly
•Master Apportionment Agreement
50% of South Saskatchewan’s water
must enter Saskatchewan
•maximum daily production is
120 million litres of water from
Oldman
•6% of Canadians not served by
wastewater treatment
•41% now receive tertiary treatment
Lethbridge &
Calgary apply
UV disenfection
after tertiary
Treatment (sludge
used as fertilizer)
Types of Pollution: Pathogens
• Waterborne disease from viruses, bacteria, etc.,
contributes to 5 million deaths per year.
• Diarrhea: 4 billion cases/year, 2.2 million deaths
• Intestinal worms: 1 in 10 people in developing world
• Blindness from trachoma: 6 million people
• Schistosomiasis from blood flukes: 200 million people
See: http://www.trachoma.org/
+2.5 to +3.3C
3 to 7%
Alberta
Population
1991: 2,545,553
2001: 2,974,807
A 16% increase in
10 years
Often locate near water bodies for:
•Transportation
•Clean Water Source
•Cooling
•Effluent Discharge
Contamination of groundwater or
large water bodies leads to decades,
centuries or more of pollution!
•17% of Canadian municipalities report
a water availability problem
•10% of Canadians rely exclusively on
groundwater (population growth is
problematic in these areas)
•Canadians use more water per capita than
anyone else in the world and our water is
the cheapest
1. Correct leakage (thousands of L)
2. Use efficient toilets and washers
3. Take shorter showers
4. Don’t over-irrigate lawn & garden
5. Be aware of water use
POINT SOURCES
•Septic systems
•Leaky petroleum pipelines/tanks
•Industrial chemical leaks, spills & discharge
•Municipal landfill sites
•Livestock waste
•Leaky sewer lines
•Wood preservation chemicals
•Tailings in mining areas
•Fly ash from coal-fired power plants
•Sludge disposal areas at petroleum refineries
•Sewage or sewage sludge fertilization
•Graveyards
•Road and highway salt & salt storage runoff
•Wells for disposal of liquid wastes
•Highway or railway accident spills
•Coal tar at old coal gasification sites
•Asphalt production and equipment cleaning
sites
Distributed Sources of Water Pollution
•Fertilizers on agricultural land
•Pesticides on agricultural land and forests
•Lawns, gardens and golf courses
•Phosphates from car washes & laundry
•Contaminants in rain, snow, and dry
atmospheric fallout
•71% of Earth’s Surface
•Reservoir for CO2
•Temperature regulator
•Habitat for 250 000 species
•Dilution of Pollutants
•Resources
•Species rich
•Dampen wave energy
•Food and shelter for fish
and invertebrates
•Antimicrobial and antiviral
compounds
AN ECOSYSTEM UNDER THREAT
- rising water temperature
- land reclamation
- siltation
- tourism
- rising seas
Declining concentrations of photosynthetic
pigments within the zooxanthellae
Partially enclosed bodies of water formed
where freshwater from rivers and streams
flows into the ocean
Transition: FRESHWATER to SALTWATER
Photo:
Campbell River Estuary
Nature Conservancy of Canada
Tidal, sheltered, highly productive bodies of water
Varied in form: bays, lagoons, inlets etc.
Shore birds, fish, crabs and lobsters, marine
mammals, shellfish, marine worms, sea birds,
and reptiles
1. Euphotic Zone
•Upper 100 – 200 m
•Sunlight permits photosynthesis
phytoplankton
whales
zooplankton
small fish
tuna
mackeral
seals
decomposer
& scavenger
2. Bathyl Zone (200m – 2km)
•Twilight
•Low density of large animals
(eg. sperm whales, giant squid)
3. Abyssal Zone (2km+)
•Very little light penetration
•Animals adapted to darkness
Benthic Environment = ocean floor
http://msnbc.com/news/674647.asp?0sl=-42&cp1=1
1. Littoral Zone
•High nutrient availability
•Available sunlight
•Most productive zone of lake
•Rooted plants (producers)
•Fish, frogs, turtles, worms, crustaceans
and insects
2. Limnetic zone
•Further from shore, few or no rooted plants
•Phytoplankton, zooplankton
•Fish (some large)
OVERTURN 4°C
OLIGOTROPHIC
EUTROPHIC
MESOTROPHIC
3.
http://users.rcn.com/jkimball.ma.ultranet
Wetland Environments
•Cover 14 to 18% of Canada
•Mainly just to the south of treeline in discontinuous and
sporadic permafrost
•Pockets further north
•Major carbon sink
•Potential future source of greenhouse gases
•Hydrophyllic vegetation present due to water table at or
above mineral soil
Bog
•
•
Sphagnum moss dominated
Receives nutrients only from precipitation
Fen
•
•
A peatland receiving nutrients from mineral soil below
Flora is more abundant and diverse, including sedges, grasses,
shrubs and even trees (tamarack)
Swamp
•
•
•
A wooded wetland
May develop into a peatland
Coniferous and deciduous trees, shrubs, herbs and mosses
Marsh
•
•
Periodically inundated wetland (fresh or salt water)
Little peat accumulation
Why does peat accumulate ?
•Production by plants exceeds decomposition
•Abundant growth due to available moisture during
growing season
•Preservation of plants (cool conditions)
•Saturated conditions - slow, anaerobic decomposition by
methanogenic bacteria
•Release of methane rather than CO2
Salmonid Species
Chinook
Chum
Trout
Coho
Pink
Cutthroat
Sockeye
(Steelhead)
Dolly Varden
Pacific Cod
Rockfish
Flounder
Herring
Eel
Commercial Fishing
• $500 million yr-1 industry (salmon)
• 8 million fish caught annually
Aquaculture
•$400 million yr-1
•Mainly salmon
Shellfish
•clams and oysters
Shellfish
Shrimp, scallops, crabs
Birds
Eagle, vulture, heron, cormorant,
swan, goose, grebe, duck, hawk,
falcon, grouse, ptarmigan, quail,
crane, plover, sandpiper, gull, finch,
woodpecker, owl, jay, raven, swallow
wren, warbler, sparrow, blackbird
Marine mammals
Whales, porpoises, dolphins,
sea otters, seals, sea lions
http://www2.news.gov.bc.ca/nrm_news_releases/2002AGF0020-000827.htm
Closures of shellfish harvesting
•sewage contamination
•high levels of dioxins and furans
Quotas are lower
every year
FINFISH:
Cod, haddock, plaice, flounder,
herring, mackerel, tuna, salmon
and capelin
INVERTEBRATE:
Shrimp, lobster, crab, scallops, clams
Pits animal
rights activists
against
fishing industry
Photo: CBC
(also leads to a decline in sea bird populations)
Source: NCAR
Annual average surface water temperature in
the Labrador Sea vs. North Atlantic Oscillation
•Falling temperatures: the result
of increased ice sheet melting? NAO?
change in thermohaline circulation?
•Salinity is also on the decrease
•Temperature and salinity changes
alter the spatial distribution and health
of a species
•These changes are thought to be
related to the collapse of the cod
fishery (with overfishing and predation)
•Damages ocean floor environments
•Catch too many fish/ too young
YEAR TONNES
VALUE
1/3 of
suitable
shellfish
sites are
closed
due to
contamination
Lobster Dispute (Nova Scotia)
•1760 Treaty between Chief
Augustine (Micmac) and
King George
•Guaranteed aboriginal
rights to use resources
•Dispute with non-native
fishers in regulated industry
•Government allows just 40
traps during off-season:
confiscated boats and traps
•Violence escalated in ’99/’00:
police rammed boats, fires
set by both sides
Cause: mismanagement of
lobster fishery
• Over 1 million km2 of shelf waters
• Most of food for Canadian Inuit
• ¼ of productivity of Atlantic/Pacific
due to thick sea ice
• Highest productivity near polynyas and
between shorefast and drifting pack ice
Source: Yngve Kristoffersen
•Input of water is from the Norwegian
Current (warmer and more saline - NA drift)
•Beaufort Sea Gyre clockwise due to polar
easterlies
•Cold, relatively fresh water leaves the
Arctic Ocean via the Fram Strait (becomes
the East Greenland Current)
•Net export of water (little evaporation)
Differences from fresh water
•Freezes between -1.65°C and -1.92°C
(more heat loss required to freeze)
•Maximum density is freezing point
(water column is destabilized)
Mixed layer of several metres required
for freeze-up !
Pack Ice
Far from shoreline (moves due to
currents and winds)
Shorefast Ice: Close to shore but still moves up
and down
Ice foot:
Frozen solid to the shore (unaffected
by tides), formed by wave action
The ice foot is separated from shorefast ice by a
tidal crack
International North Water Polynya Study
http://www.fsg.ulaval.ca/giroq/now/polyb.jpg
Frazil forms near the surface in the mixed layer
around suspended particles (centres of nucleation)
In calm water: Frazil accumulates on the surface
forming grease ice
In turbulent water: Frazil freezes into balls/pans
which freeze together when the ice dampens the
waves
When there is stable ice cover, elongated crystals
grow downward
Limits exchange of sensible and latent heat
(lowers temperature and precipitation)
Increases albedo (decreases temperature)
Limits exchange of oxygen and carbon dioxide
Blocks light, virtually eliminating photosynthesis
Restricts range of some marine mammals
(eg. whales) but extends the range of others
(sea ice is important to seals)
•Semi-permanent areas of open water
•Remain unfrozen despite high arctic climate
Latent Heat Polynyas:
Currents or winds remove new ice
Sensible Heat Polynyas:
Warm water continually brought upward to
a site
•Polynyas are biologically important
•Oxygen exchange with the air allows marine
life to continue throughout the winter
•Nutrients brought by currents maintain an
active food chain in the winter
•Marine mammals like walrus and whales can
live here year-round
•Important sites for northern hunting culture
Arctic sea-ice extent decreased by 2.9%
per decade (1978-1996)
Sea ice has thinned
Northwest Passage new route from Asia to
Europe?
•Mainly subsistence hunting/fishing
•Commercial fishery includes:
- Arctic Char ($1.2 million yr-1)
- Turbot ($ 1 million yr-1)
- clams, shrimp, scallops (local)
Arctic
Char
(Balena mysticetus)
“Greenland Right Whale”
•A baleen whale:
Filters zooplankton and krill through a mesh
of thin, flexible, bony plates up to 3m long,
suspended from the upper jaw
•20m in length; weighs up to 70 tons
Females are larger than males
Distribution:
Between 55°N and the permanent polar pack
•Original population around 50000
Mid 1800’s: 5 populations near extinction
1970’s: 4500
Today: 8500
•Spend winter around polynyas
•Hide from killer whales around ice floes
•Canada withdrew from the IWC in 1982
•Cetacean Protection Act (Canada)
Inuit: 1 bowhead per year (1995)
Delphinapterus leucas
“White Whale”
•Most common whale in Canadian Arctic
•4-5m in length, 540-765 kg
•Nutrition: Bottom-dwelling fish, benthic
invertebrates, squid & arctic cod
•Lifespan: Approximately 25-30 years
Population:
10000 in Lancaster Sound
10000 in Beaufort Sea
1500 in east Hudson Bay
25000 in west Hudson Bay
Beluga whale carcasses are toxic waste!
20% have cancers at death
Toxins accumulate most in fatty tissues
List of toxins
include
chemicals
banned for
decades
Monodon monoceros
•Spiralled tusk – function uncertain (mating?)
•Narwhals are 5m long + 2m tusk
•600 -1200 kg (males larger)
•More restricted distribution beluga whale:
Many in Lancaster Sound area.
Seldom seen south of the Arctic Circle
Migratory: winters in heavy pack ice of
Baffin Bay and in the Davis Strait – some in
mouth of Hudson Strait
• Migrate northward in summer
• Narwhals dive more deeply than beluga whales
Nutrition: Crustaceans, molluscs, squid, shrimp,
Arctic Cod
Population: 20000 in Lancaster Sound, 2000 in
north Hudson Bay
Hunting:
Can only be hunted by Inuit for subsistence and
domestic purposes (quota since 1977)
• They are hunted for their tusks and for muktuk
Orcinus orca
•Hunt in packs of 3-40 animals
Location:
Throughout world’s oceans but most abundant in
cool, temperate waters.
In Arctic, they are found from Davis Strait to
Lancaster Sound and may penetrate Hudson Bay.
Killer whales like to avoid heavy pack ice
Migratory: Follow migration herds of seals;
migrate south in winter
Nutrition: Eat fish, squid, seabirds, seals (dislodge
them from beneath ice floes), other cetaceans
Size: Males 6-9m, females 4-5m
Lifespan: 40-50 years