1. If there is magic on this planet it is contained in water.
LOREN EISLEY

2. Aquatic Biodiversity (8)
Saltwater and freshwater aquatic life zones cover almost three-fourths of the earth’s surface with oceans dominating the planet.
1. 71% saltwater
2. 2.2% freshwater
The global ocean is one continuous body of water, it is divided into 4 large areas (Atlantic, Pacific, Arctic, and Indian Oceans). The Pacific is the largest, containing half of the Earth’s water and cover 1/3 of the Earth’s surface.
Most freshwater is trapped in glaciers and ice caps. Liquid water is found (listed from most to least) in:
1. Groundwater
2. Lakes
3. Soil moisture
4. Atmospheric moisture
5. Rivers
6. Streams

3. Aquatic Life Zones
Aquatic life zones are equivalents to biomes on land.
The key factors determining biodiversity in aquatic systems are:
1. Temperature
2. Dissolved oxygen content
3. Availability of food
4. Availability of light and nutrients
necessary for photosynthesis
5. Salinity or the amount of
dissolved salts(Mainly NaCl)
in the water
Aquatic life zones are categorized into
two major types:
1. Saltwater or marine which include: oceans, estuaries, coastal wetlands, shorelines, coral reefs, and mangrove forests.
2. Freshwater which include: lakes, rivers, streams, and inland wetlands.

4. Oceanic Life Zones
Coastal Zone: that region in which tides expose the sea bottom for some part of each day. The habitats are alternately submerged under salt water and waterlogged for hours and then exposed to the air and dried out for hours. Also known as littoral, or intertidal zone.
Pelagic Zone: located seaward of the coastal zone’s low-tide mark, this contains the vast open waters of the ocean. Two subdivision are recognized:
1.  Neretic Zone (Sublittoral zone): the water overlying the continental shelf. With the exception of Antarctica, these waters usually extend to a depth of 600 ft. Sunlight penetrates the entire water column.
2. Oceanic Zone: The region of the sea extending from the edge of the continental shelf, over the continental slope, and over ocean floor. It is characterized by darkness and tremendous pressure. Vertical life zones are significant here.

5. Further Divisions are Based on Light
Euphotic  zone: The top of the water column as far down as light is available for photosynthesis. Depending upon water clarity, the bottom of the euphotic zone is about 500 ft below sea level. Also known as epipelagic zone.
Aphotic zone: the remainder of the water column below the euphotic zone. Food chains usually begin with detritus or living algae and bacteria sinking from above.  This zone is further subdivided by depth as follows:
Mesopelagic zone: 500 to 3,280 ft below the sea surface. Bathyal zone: 3,280 to 13,000 ft below the sea surface Abyssal zone: 13,000 to 20,000 ft below the sea surface Hadal zone: 20,000 to 35,000  ft below the sea surface.
Benthic Zone: This zone contains all the habitats of the sea bottom, whether in coastal, continental shelf, or deep sea environments. Organisms may live within the bottom material or on its surface.

6. Euphotic Zone Continental shelf
High tide
Low tide
Sun
Depth in meters
Coastal Zone
Open Sea
Sea level
Photosynthesis 50
Euphotic Zone
Estuarine Zone
100
Continental shelf
200
500
Bathyal Zone
Twilight
1,000
1,500
2,000
Water temperature drops rapidly between the euphotic zone and the abyssal zone in an area called the thermocline .
Abyssal Zone
3,000
Darkness
4,000
5,000
10,000 5 10 15 20 25 30
Water temperature (°C)

7. Species Live in Specific Depths
Life in most aquatic systems life is found in surface, middle, and bottom layers. Aquatic systems contain floating, drifting, swimming, bottom-dwelling, and decomposer organisms.
Saltwater and freshwater life zones contain several major types of organisms:
Plankton: Weak swimming, free floating organisms.
A. Phytoplankton (drifting Plants): Photosynthesizing groups of algae. With the addition of rooted shoreline plants, these are the primary producers that support most aquatic food webs.
B. Zooplankton (drifting animals): Primary consumers (herbivores) and secondary consumers that include protozoa and jellyfish.
Food stock for larger consumers
C. Ultra plankton: Small photosynthetic bacteria responsible for 70% of the productivity near the ocean surface.

8. Nekton: strongly swimming consumers such as fish, turtles, and whales
Nekton: strongly swimming consumers such as fish, turtles, and whales. Top consumers in the aquatic ecosystem
Benthos: consist of bottom dwellers such as oysters, lobsters, clams, worms, and crabs. Primary consumers and decomposers
Decomposers: mostly bacteria that recycle organic material and release nutrients to be used by aquatic primary producers.

9. Saltwater ecosystems are irreplaceable reservoirs of biodiversity and provide major ecological and economic services.

10. Marine Ecosystem
The coastal zone is the warm, nutrient rich, shallow water that extends from the high-tide mark on land to the gently sloping, shallow edge of the continental shelf.
Makes up less than 10% of the ocean’s area.
Contains 90% of all marine species and is the site of most commercial fisheries.
High NPP (Net primary productivity) based on supplies of sunlight and nutrients.
Include estuaries, coastal wetlands, mangrove forests and coral reefs.
A wetland is a land area that is saturated with water, either permanently or seasonally, such that it takes on the characteristics of a distinct ecosystem. Includes Estuaries, marshes, bogs, swamps and seagrass beds. Wetlands are also considered the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal life.

11. Estuaries
An estuary is a partly enclosed coastal body of brackish water (mix of fresh and salt water) with one or more rivers or streams flowing into it, and with a free connection to the open sea.
Three of the main challenges of estuarine life are the variability in salinity, temperature and sedimentation. Many species of fish and invertebrates have various methods to control to the shifts in salt concentrations and are termed osmoregulators. Many animals also burrow to avoid predation and to live in the more stable sedimental environment. Phytoplankton are key primary producers in estuaries.
Estuaries form a transition zone between river environments and maritime environments and are subject to both marine influences, such as tides, waves, and the influx of saline water; and riverine influences, such as flows of fresh water, pollutants and sediment. The inflows of both sea water and fresh water provide high levels of nutrients in both the water column and sediment, making estuaries among the most productive and fertile natural habitats in the world.

12. Human Impact on Estuaries
Estuaries provide habitats for many fish nurseries, depending upon their locations in the world, such as salmon and sea trout. Also, migratory bird populations.
Just one acre of estuary provides $75,000 worth of free waste treatment, and has a value of about $83,000 when recreation and fish for food are included.
Prime Kansas farmland has a top value of $1,200 and an annual production value of $600.
The banks of many estuaries are amongst the most heavily populated areas of the world, with about 60% of the world's population living along estuaries and the coast. As a result, many estuaries are suffering degradation by many factors, including sedimentation from soil erosion from deforestation, overgrazing, and other poor farming practices; overfishing; drainage and filling of wetlands; eutrophication due to excessive nutrients from sewage and animal wastes; pollutants including heavy metals, polychlorinated biphenyls, and hydrocarbons from sewage inputs; and diking or damming for flood control or water diversion.

13. Salt Marsh
A salt marsh is a coastal ecosystem in the upper coastal intertidal zone between land and open salt water or brackish water that is regularly flooded by the tides. It is dominated by dense stands of salt-tolerant plants such as herbs, grasses, or low shrubs. These plants are terrestrial in origin and are essential to the stability of the salt marsh in trapping and binding sediments. Salt marshes play a large role in the aquatic food web and the delivery of nutrients to coastal waters. They also support terrestrial animals and provide coastal protection (defense against flooding and erosion).
The ground here is saturated with water and there is little oxygen, so decay takes place slowly. It has a surface inlet and outlet, and contains many invertebrates. It is also the breeding ground for many ocean animals. Ex. crabs and shellfish. They are susceptible to the same human impact as estuaries.

14. Mangrove Swamp
Mangrove swamps are coastal wetlands found in tropical and subtropical regions. They are characterized by halophytic (salt loving) trees, shrubs and other plants growing in brackish to saline tidal waters. Mangrove swamps protect the land from soil erosion and the effects of storms. They also act as a form of pollution control, naturally filtering out industrial and human waste.
They provide a breeding nursery for some 2000 species of fish, invertebrates, and plants.
Approximately 35% of mangrove area was lost during the last several decades of the 20th century. It is estimated that shrimp farming causes approximately a quarter of the destruction of mangrove forests

15. Kelp Forests
Kelp forests are underwater areas with a high density of kelp. They are recognized as one of the most productive and dynamic ecosystems on Earth (next to estuaries). Smaller areas of anchored kelp are called kelp beds.
Kelp forests occur worldwide throughout temperate and polar coastal oceans.
Kelp forests provide a unique three-dimensional habitat for marine organisms:
1. It reduces the effects of eutrophication
2. It provides shelter for fish
3. It serves as a food supply for many invertebrates
4. It protects the coastline
However, the influence of humans has often contributed to kelp forest degradation. Of particular concern are the effects of overfishing near shore ecosystems, which can release herbivores from their normal population regulation and result in the over-grazing of kelp and other algae. The implementation of marine protected areas (MPAs) is one management strategy useful for addressing such issues since it may limit the impacts of fishing and buffer the ecosystem from additive effects of other environmental stressors.

16. Intertidal Zone
Intertidal zones are an area of shoreline exposed to water during high tide and air during low tide. The movement of water brings in nutrients and takes away waste products leaving an area of rich biodiversity.
Organisms must be able to adapt to extremes in temperature, salinity, and being submerged or left high and dry.
Most intertidal organisms hold on to something, dig in or hide in shells to keep from being swept away.
Intertidal zones come in two basic forms based on the structure of the shoreline:
Rocky shores: lead to tide pools
Sandy shores (Barrier beaches): gently sloping sands that hide burrowing animals.
Runoff from land brings pollution that threaten intertidal zones.

17. Coral Reefs
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps belong to a group of animals known as Cnidaria, which also includes sea anemones and jellyfish. Unlike sea anemones, coral polyps secrete hard carbonate exoskeletons which support and protect their bodies. Reefs grow best in warm, shallow, clear, sunny and agitated waters. They are the most biologically diverse of all marine ecosystems.
Often called "rainforests of the sea", coral reefs form some of the most diverse ecosystems on Earth. They occupy less than 0.1% of the world's ocean surface, about half the area of France, yet they provide a home for 25% of all marine species, including fish, mollusks, worms, crustaceans, echinoderms, sponges, tunicates and other cnidarians.
The waters where coral reefs are found are often poor in nutrients. Yet, other factors are favorable such as temperature, sunlight year round, and zooxanthellae (symbiotic algae).

18. Coral reefs deliver ecosystem services to tourism, fisheries and shoreline protection. The annual global economic value of coral reefs is estimated between US$ billion.
Important ecological and economic services
1. Moderate atmospheric temperatures (bind carbon dioxide from the atmosphere to build their skeletons = reduce greenhouse gas)
2. Act as natural barriers protecting coasts from erosion
3. Provide habitats
4. Support fishing and tourism businesses
5. Provide jobs and building materials (the sand and rubble they leave on the shores can be used to make concrete)
6. Studied and enjoyed
The Brain Coral
Coral reefs are fragile ecosystems, partly because they are very sensitive to water temperature. They are under threat from climate change (If the ocean gets too hot, corals will bleach or their zooxanthellae leaves or dies. Without their algae, the corals will starve to death), oceanic acidification, blast fishing, cyanide fishing for aquarium fish, overuse of reef resources, and harmful land-use practices, including urban and agricultural runoff and water pollution, which can harm reefs by encouraging excess algal growth.

19. Seagrass Beds
Seagrasses form extensive beds or meadows. In temperate areas, usually one or a few species dominate, whereas tropical beds usually are more diverse.
Seagrass beds are highly diverse and productive ecosystems, and can harbor hundreds of associated species from all phyla, for example juvenile and adult fish, algae, mollusks, bristle
worms, and nematodes. Seagrass herbivory is a highly important link in the food chain, with hundreds of species feeding on seagrasses worldwide, including green turtles, dugongs, manatees, fish, geese, swans, sea urchins and crabs.
Some fish species that feed on the seagrass raise their young in adjacent mangroves or coral reefs. Seagrass trap sediment and slow water movement, causing suspended sediment to fall out. The trapping of sediment benefits coral by reducing sediment loads in the water. When humans drive motor boats over shallow seagrass areas, sometimes the propeller blade can tear out or cut the seagrass. Protecting seagrass meadows include nutrient and pollution reductions, using marine protected areas, and restoration using seagrass transplantation.

20. Open Sea Separated into 3 major zones:
1. The euphotic zone: brightly lit upper zone where phytoplankton carry out about 40% of the world’s photosynthesis. Nutrients levels are low but dissolved oxygen is high. Dominated by large, fast swimming predatory fish like tuna, swordfish and sharks.
2. Bathyal zone: dimly lit middle zone. Contains zooplankton (don’t photosynthesize) and smaller fish that migrate to the surface to feed.
3. Abyssal zone: the deep, dark and cold zone. It is high in nutrient due to marine snow (dead and decaying organisms sinking from above) and low in oxygen. The marine snow allows the deep bottom to support large numbers of species even though there is no photosynthesis.
Deposit feeders (take in mud and extract nutrients) and filter feeders (extract nutrients from the water) take advantage of marine snow in the deep open sea.

21. Ocean currents
There are a number of ocean currents found around the Earth. A current is like a vast river within the ocean, flowing from one place to another. These currents are caused by differences in temperature, differences in salinity, and by wind. Currents are responsible for a vast amount of movement of the water found in the Earth’s oceans.
The Northern Hemisphere is dominated by land and the Southern Hemisphere by ocean.
Temperature differences between summer and winter are more extreme in the north because land warms and cools faster than water.
Heat is transported from the equator to the poles by air and ocean currents
Surface ocean currents are generally wind driven and develop their typical clockwise spirals in the northern hemisphere and counter clockwise rotation in the southern hemisphere because of

22. Great Ocean Conveyor Belt
In the deep ocean, the predominant driving force is differences in density, caused by salinity and temperature variations (increasing salinity and lowering the temperature of a fluid both increase its density, cold salty water sinks).
Warm water move north in the Atlantic Ocean and loses heat to the atmosphere and sinks (down welling). Cold water from Antarctica enters the Indian and Pacific oceans where the atmosphere warms it and the water comes to the surface (upwelling).
Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water. The nutrient-rich upwelled water stimulates the growth and reproduction of primary producers such as phytoplankton.

23. The Gulf Stream
The Gulf Stream, together with its northern extension towards Europe, the North Atlantic Drift, is a powerful, warm, and swift Atlantic ocean current that originates at the tip of Florida, and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean.
The Gulf Stream influences the climate of the east coast of North America from Florida to Newfoundland, and the west coast of Europe. Although there has been recent debate, there is consensus that the climate of Western Europe and Northern Europe is warmer than it would otherwise be due to the North Atlantic drift, one of the branches from the tail of the Gulf Stream.

24. Degrading Marine Systems: Human Impact
Human activities threaten aquatic biodiversity and disrupt ecological and economic services provided by saltwater systems.
Major threats to marine systems
1. Coastal development: destroys and pollutes coastal habitats
2. Overfishing
3. Runoff of nonpoint source pollution: fertilizers, pesticides, livestock waste
4. Point source pollution: Sewage from cruise ship and oil spills
5. Habitat destruction
6. Introduction of invasive species
7. Climate change from human activities: warmer ocean temperatures (coral bleaching) and ocean acidification (Ocean acidification is the ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere

25. Freshwater Ecosystems
NATURAL CAPITAL
Freshwater Systems
Freshwater ecosystems provide major ecological and economic services and are irreplaceable reservoirs of biodiversity.
Ecological Services
Economic Services
Climate moderation
Food
Nutrient cycling
Drinking water
Freshwater life zones include:
1. Standing (lentic) water such as lakes, ponds, and inland wetlands.
2. Flowing (lotic) systems such as streams and rivers.
Waste treatment
Irrigation water
Flood control
Hydroelectricity
Groundwater recharge
Habitats for many species
Transportation corridors
Genetic resources and biodiversity
Recreation
Scientific information
Employment

26. Lakes
Lakes are large natural bodies of standing freshwater formed from precipitation, runoff, and groundwater seepage. In freshwater aquatic environments sunlight and/or phosphorus levels limit the amount of primary production.
Lakes are divided into four zones based on depth and distance from shore
Littoral zone
Limnetic zone
Profundal zone
Benthic zone
Littoral

27. Littoral Zone
A shallow area near the shore, to the depth at which rooted plants stop growing. Ex. Animals: frogs, snails, insects, fish, Ex: plants: cattails, rushes and water lilies.
Littoral zones are at particular risk for two reasons. First, human settlement is often attracted to shorelines, and settlement often disrupts breeding habitats for littoral zone species. For example, many turtles are killed on roads when they leave the water to lay their eggs in upland sites.
Fish can be negatively affected by docks and retaining walls which remove breeding habitat in shallow water. Some shoreline communities even deliberately try to remove wetlands since they may interfere with activities like swimming.
An equally serious problem is the tendency to stabilize lake or river levels with dams. Dams removed the spring flood which carries nutrients into littoral zones, and reduces the natural fluctuation of water levels upon which many wetland plants and animals depend.[

28. Limnetic Zone
The limnetic zone is the well-lit, open surface waters in a lake, away from the shore. This is the main photosynthetic body of the lake. This zone produces the oxygen and food that support the lake's consumers.
It can be defined as the lighted surface waters in the area where the lake bottom is too deep and unlit to support rooted aquatic plants. This area is occupied by a variety of phytoplankton, consisting of algae and cyanobacteria, as well as zooplankton, small crustaceans, and fish.
Some large fish spend most of their time here, with occasional visits to the littoral zone to feed and breed.

29. Profundal and Benthic Zone
The profundal zone is a deep zone of an inland body of freestanding water, such as a lake or pond, located below the range of effective light penetration. This is typically below the thermocline, the vertical zone in the water through which temperature drops rapidly. The profundal zone is part of the aphotic zone.
The benthic zone is the bottom of the lake. It is inhabited by decomposers and some fish. It is nourished by dead matter sinking from the littoral and limnetic zones.

30. Thermal Stratification
Thermal Lake stratification is the separation of lakes into three layers based on temperature:
1. Epilimnion - top of the lake.
2. Metalimnion (or thermocline) - middle layer that may change depth throughout the day.
3. Hypolimnion - the bottom layer.
The thermal stratification of lakes refers to a change in the temperature at different depths in the lake, and is due to the change in water's density with temperature. Cold water is denser than warm water and the epilimnion generally consists of water that is not as dense as the water in the hypolimnion.
In temperate regions where lake water warms up and cools through the seasons, a cyclical pattern of overturn (Oxygen is brought from the surface to the lake bottom and nutrients from the bottom are brought to the top) occurs that is repeated from year to year as the cold dense water at the top of the lake sinks.

31. Spring and Fall Turnover
In the winter ice forms and the entire lake becomes one temperature (4o C) and acts as one layer and no turnover.
Hypolimnion
In the spring the warming/melting of the ice layer at the surface and the much smaller temperature differences in the water column, winds and storms are able to create a spring turnover with little difficulty. Oxygen and nutrients get distributed throughout the water column as the water mixes.
Epilimnion
Thermocline
Hypolimnion
In the summer the lake becomes stratified and the thermocline stops turnover.
In the fall the temperatures begin to drop, the surface layer becomes more dense, and it sinks to the bottom. This mixing brings nutrients from the bottom up to the surface and sends oxygen to the bottom (fall overturn).

32. Lake Nutrients
Eutrophication: (well nourished body of water) A natural nutrient enrichment of a shallow lake, estuary, or slow moving stream, mostly from runoff of plant nutrients such as phosphates and nitrates from the surrounding land. High NNP
Oligotrophic: (Under nourished) A lake that is low in nutrients and will have very clear water. Low nutrients reduce organisms like algae that make the water murky. Low NPP.
Cultural eutrophication: (water pollution) near urban areas, human activities increase nutrients above the natural nutrient enrichment. Nitrogen-phosphorus containing substances make their way to bodies of water from: farmlands, animal feedlots, chemically fertilized backyards, mining site, municipal sewage.
Oligotrophic lake
Cultural Eutrophication is considered pollution.
Because this gets into our water supply from runoff, etc.,
and is something that is not normally in the water,

33. Problems with Cultural Eutrophication
During hot weather and drought, this nutrient overload produces dense growths or “blooms” of organisms.
The water is cloudy and usually resembles pea soup because of the algae, duckweed and cyanobacteria that are supported by the nutrients.
These blooms reduce lake productivity and fish growth by blocking solar energy for phytoplankton that support fish.
When the blooms die their decomposition by aerobic bacteria deplete DO. This can kill fish and other aerobic animals. If nutrients continue to be added the water loses enough DO to allow anaerobic organisms to take over. These organisms produce smelly gases like hydrogen sulfide and flammable methane.
According to the EPA about 33% of medium lakes and 85% of large lakes near major population centers in the U.S. have some degree of cultural eutrophication.

34. Preventing, Reducing and Fixing Cultural Eutrophication
Prevention and reduction techniques:
1. Use expensive waste treatment to remove nitrates and phosphates before waste water enters lakes and oceans.
2. Banning or limiting phosphates in household detergents and cleaners.
3. Use soli conservation to reduce soil nutrient runoff.
Fixing Eutrophication (IPM)
Use herbicides and algaecides to kill plants
Deepen lakes to increase area for animals to live and increase oxygen content.
3. Artificially oxygenating the water by pumping in fresh oxygen.
4. Introducing competitors or insects that eat the plants.
5. Mechanically remove excess weeds and plants.
La Jolla, San Diego: Harmful algal bloom (HAB) events can be very bad for us. People who eat shellfish from waters experiencing toxic blooms can become very ill and can even die.

35. Flowing Water: Stream and Rivers
When precipitation does not sink in the ground into becomes surface water. It becomes runoff when it flows in a stream. A watershed or drainage basin is the land that delivers runoff, sediment and dissolved substances to a stream.
There are 3 zones in the downhill flow of water:
1. Source zone: Narrow headwaters, shallow, cold, clear and swiftly flowing. As the water flows over rapids and waterfalls oxygen dissolves in from the air. DO is very high but productivity is low. The small amount of nutrients come from decaying plants and insects that fall in the water.
Living organisms are dominated by strong swimming, cold water fish (trout) that need a lot of DO. Other fish are flat to secure spots under rocks. Most plants stick to rocks under water.

36. 2. Transition zone: Here headwaters merge to form wider, deeper slower moving waters. They tend to have more suspended material and lower DO. They support more producers and fish like bass and catfish.
3. Floodplain zone: Slower-moving water, less oxygen, warmer temperatures, and lots of algae and cyanobacteria.

37. Natural Capital
Ecological Services of Rivers
Deliver nutrients to sea to help sustain coastal fisheries
Deposit silt that maintains deltas
Purify water
Renew and re-nourish wetlands
Provide habitats for wildlife

38. Inland Wetlands
Inland wetlands are lands covered with freshwater all or part of the time (excluding lakes, rivers and reservoirs) and are located away for the coastal area. They act as vital sponges that absorb and store excess water from storms and provide a variety of wildlife habitats.
A marsh is a type of wetland that is dominated by herbaceous rather than woody plant species. Marshes can often be found at the edges of lakes and streams, where they form a transition between the aquatic and terrestrial ecosystems. They are often dominated by grasses, rushes or reeds. If woody plants are present they tend to be low-growing shrubs. Freshwater marshes make up the most common form of wetland in North America.
Prairie potholes are found in the northern parts of North America. This landscape was once covered by glaciers, and as a result shallow depressions were formed in great numbers. These depressions fill with water in the spring. They provide important breeding habitat for many species of waterfowl. Some pools only occur seasonally while others retain enough water to be present all year.

39. A swamp is a wetland that is forested
A swamp is a wetland that is forested. Many swamps occur along large rivers where they are critically dependent upon natural water level fluctuations. Other swamps occur on the shores of large lakes. Some swamps have hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodic inundation.
A bog is a mire that accumulates peat, a deposit of dead plant material—often mosses, and is one of the four main types of wetlands.
A floodplain or flood plain is an area of land adjacent to a stream or river that stretches from the banks of its channel to the base of the enclosing valley walls and experiences flooding during periods of high discharge.

40. Ecological Services of Wetlands
Provide free ecological and economic services
1. Filter and degrade toxic wastes and pollutants
2. Reduce flooding and erosion absorbing storm water, overflows from lakes and streams and releasing them slowly
3. Help to replenish streams and recharge groundwater aquifers
4. Increase biodiversity by supplying many habitats and niches
5. Food (berries, fish and shellfish) and timber
6. Recreation areas
Developers and farmers want Congress to revise the definition of wetlands. This would make 60-75% of all wetlands unavailable for protection. The Audubon Society estimates that wetlands provide water quality protection worth $1.6 billion per year, and they say if that wetlands are destroyed, the U.S. would spend $7.7 billion to $31 billion per year in additional flood-control costs.
Freshwater wetlands are categorized into marshes, bogs, swamps etc. based on three properties:
Hydrology is the study of the movement, distribution, and quality of water it contains.
The type of soil that constitutes the shores and bottom of wetland.
The composition of species or biodiversity of living organisms (especially plants) that live in the area.

41. Case Study: the Florida Everglades
The world’s largest ecological restoration project involves trying to undo some of the damage inflicted on the Everglades by human activities.
90% of park’s wading birds have vanished.
Other vertebrate populations down 75-95%.
Large volumes of water that once flowed through the park have been diverted for crops and cities.
Runoff has caused noxious algal blooms.
As Miami develops, it encroaches on everglades. Plus, it prompts people vs. wildlife. It is freshwater and local areas are draining it.
Build huge aqueduct, or find other sources of fresh water and protect it federally under endangered species act, etc.
Loss of wetlands has led to
Increased flood and drought damage
Lost due to
Growing crops, Mining, Forestry, Oil and gas extraction, building highways and Urban development

42. Degrading Freshwater Systems: Human Impact
Human activities threaten biodiversity and disrupt ecological and economic services provided by freshwater lakes, rivers, and wetlands.
Threats
1. The creation of dams and water-diversion systems (40% of rivers) blocks migration routes for fish and disrupts habitats.
2. Water withdrawal for human use shrinks and degrades habitats.
3. Runoff from agricultural and urban areas hurts water quality.
4. Draining of wetlands for development of cities and farm depletes habitats.
5. Overexploitation and pollution threaten groundwater supplies.
6. Invasion of exotic species can harm native animals and plants.
7. Global warming may lead to devastating floods and droughts.
Solutions
1. Restrict the construction of dams.
2. Provide incentives for farming business to reduce the use of pesticides.
3. Establish protected wetlands areas.
4. Regulate water withdrawal for human use.

43. By treating the oceans with more respect
and by using them more wisely,
we can obtain more from these life-supporting waters
while also maintaining healthy
and diverse marine ecosystems
BRIAN HALWEIL

44. Sustaining Aquatic Biodiversity (11)
Biodiversity of the oceans follow three general patterns:
1. Greatest marine biodiversity occurs in coral reefs, estuaries and the deep ocean floor.
2. Biodiversity is higher near the coast then in the open ocean because the coast has more producers and habitats.
3. Biodiversity is higher in the bottom region than the surface because the bottom has more producers and habitats.
Human activities are destroying aquatic habitats
(H. I. P. P. C. O.)
H. Destruction of coral reefs, mangrove swamps, coastal wetlands and rivers where 90% of the fish living in the ocean spawn. Trawler boats drag large nets that tear up the bottom of the ocean. Dams and excess water withdrawal form rivers and lakes destroy freshwater habitats. 51% of freshwater fish are threatened.
Many inland wetlands have been drained or filled for agriculture or (sub)urban development.
Dams, diversions and canals have fragmented about 40% of the world’s 237 large rivers.

45. Area of ocean before and after a trawler net, acting like a giant plow, scraped it.
I. Hundreds of harmful invasive species have been accidentally or deliberately introduces into aquatic systems. These invaders are responsible for 2/3 of the fish extinctions and cost the country 14 million dollars per hour. No matter what other damage an invader does the number one problem is that they outcompete native species for resources.
Lake Victoria has lost their endemic fish species to large introduced predatory fish.
Reasons for Lake Victoria’s loss of biodiversity:
1. Introduction of Nile perch.
2. Lake experienced algal blooms from nutrient runoff. Reduction of fish that eat algae.
3. Invasion of water hyacinth has blocked sunlight and deprived oxygen.
4. Nile perch is in decline because it has eaten its own food supply.

46. The Zebra Mussel:
The native distribution of the species is in the Black Sea and Caspian Sea in Eurasia. Zebra mussels have become an invasive species in North America, Great Britain, Ireland, Italy, Spain, and Sweden. They disrupt the ecosystems and damage harbors and waterways, ships and boats, and water treatment and power plants. Water treatment plants are most affected because the water intakes bring the microscopic free-swimming larvae directly into the facilities. The zebra mussels also cling on to pipes under the water and clog them.
North American invasion
They were first detected in Canada in the Great Lakes in 1988, in Lake St. Clair, located north of Detroit, Michigan, and Windsor, Ontario. It is believed they were inadvertently introduced into the lakes in the ballast water of ocean-going ships traversing the St. Lawrence Seaway. Another possible often neglected mode of introduction is on anchors and chains, although this has not been proven. Since adult zebra mussels can survive out of water for several days or weeks if the temperature is low and humidity is high, chain lockers provide temporary refuge for clusters of adult mussels that could easily be released when transoceanic ships drop anchor in freshwater ports. They have become an invasive species in North America, and as such they are the target of Federal policy to control them, for instance in the National Invasive Species Act (1996).

47. The National Invasive Species Act (NISA) was sponsored by U. S
The National Invasive Species Act (NISA) was sponsored by U.S. House Representative Steve LaTourette on 28 September 1996, and it became Public Law No (H.R. 4283) on 26 October The official purpose, as introduced, is: “To provide for ballast water management to prevent the introduction and spread of non-indigenous species into the waters of the United States, and for other purposes.” It was created to reauthorize and amend a previous measure, the Non-indigenous Aquatic Nuisance Prevention and Control Act of 1990 (NANPCA),[and one of its prime focuses is to prevent invasive species from entering the Great Lakes through ballast water.
P.P. Population growth equals more pollution( 80% of people live on or near the coast). Other problems include over-drawing fresh water, and over-building so that water can’t seep into the ground (reducing re-charge areas for aquifers)
Each year plastic items dumped from
ships and left as litter on beaches
threaten marine life.
Runoff brings pollutants to aquatic ecosystems as well as nutrients that can lead to eutrophication.
Decomposition of this excess plant material consumes dissolved oxygen which can cause hypoxia.

48. C. Climate change causes sea levels to rise (10-20 cm in the past 100 years). This rise will destroy coral reefs, swamp some low-lying areas and drowned coastal wetlands.
Coral bleaching is the loss of intracellular endosymbionts (Symbiodinium, also known as zooxanthellae) through either expulsion or loss of algal pigmentation. The corals that form the structure of the great reef ecosystems of tropical seas depend upon a symbiotic relationship with algae-like unicellular flagellate protozoa that are photosynthetic and live within their tissues. Zooxanthellae give coral its coloration, with the specific color depending on the particular species. Under stress, corals may expel their zooxanthellae, which leads to a lighter or completely white appearance, hence the term "bleached".
What causes bleaching?
increased (most commonly), or reduced water temperatures. oxygen starvation caused by an increase in zooplankton levels as a result of overfishing
increased solar irradiance (photosynthetically active radiation and ultraviolet band light)
changes in water chemistry (in particular acidification)
increased sedimentation (due to silt runoff)

49. O. The human demand for seafood is outgrowing the sustainable yield of most ocean fisheries. Industrialized fishing fleets vacuum up fish faster than they can replenish. Most fishing techniques hunt and capture one or a small number of commercially valuable species. Their large nets and long lines of hooks capture non target fish called by-catch. About 1/3 of the fish by weight are by-catch and are thrown back dead or dying. Overharvesting is the greatest threat to aquatic species.
Fishing techniques:

50. Only 1% of the world’s oceans are closed to fishing.
Purse-seine fishing: A large purse-like net is put into the ocean and is then closed like a drawstring purse to trap the fish.
Tuna is a fish typically caught in purse seines
Dolphins are a by-catch of purse seines
Long-line fishing: Lines are put out that can be up to 80 miles long w/ thousands of baited hooks on them. These are left out free-floating for days and then the boat comes back and picks them up.
Pilot whales, dolphins, sea turtles, and birds are by-catch of this technique.
Only 1% of the world’s oceans are closed to fishing.
Drift-net fishing: Each net hangs as much as 50 feet below the surface and up to 34 miles long.
Anything that comes into contact w/ these nearly invisible nets are entangled.
This leads to overfishing
Many unwanted fish and marine mammals, turtles and seabirds are caught.
With the world’s fish numbers in a decline the only way to keep catching the same number of fish is to fish for a longer period of time each year.
Trawler fishing: is used to catch shrimp, cod scallops and other fish by dragging large nets through the ocean.

51. Aquaculture "is understood to mean the farming of aquatic organisms including fish, mollusks, crustaceans and aquatic plants. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated."
Particular kinds of aquaculture include fish farming, shrimp farming, oyster farming, mariculture, algaculture (such as seaweed farming), and the cultivation of ornamental fish.
Aquaculture can be more environmentally damaging than exploiting wild fisheries on a local area basis. Local concerns include waste handling, side-effects of antibiotics, competition between farmed and wild animals, and using other fish to feed more marketable carnivorous fish. Many farmed raised fish have large amounts of parasites and sea lice.
Fish waste is organic and composed of nutrients necessary in all components of aquatic food webs. In-ocean aquaculture often produces much higher than normal fish waste concentrations. The waste collects on the ocean bottom, damaging or eliminating bottom-dwelling life. Waste can also decrease dissolved oxygen levels in the water column, putting further pressure on wild animals.

52. Laws, Treaties, Money, Sanctuaries and Reserves Protect Marine Species.
Protecting marine biodiversity is difficult:
The human ecological footprint is expanding into aquatic areas and the impact is hard to monitor.
Most of the damage to oceans and other bodies of water is not visible to most people
Many people view the ocean as an inexhaustible resource that can absorb anything we throw at it and still produce the food we need
Most of the ocean lies outside the legal jurisdiction of any country.
Clean water acts:
Safe Drinking Water Act: (SDWA, 1974) set maximum contaminant levels for pollutants in drinking water that have adverse effects on human health. Ex: Lead
Clean Water Act: (CWA, 1972) set maximum permissible amounts of water pollutants that can be discharged into waterways. Purpose is to make surface waters swimmable and fishable.
Ocean Dumping Ban Act (1988) bans ocean dumping of sewage sludge and industrial waste in the ocean.

53. Animal Protection Acts
CITES (the Convention on International Trade in Endangered Species: 1975) Its aim is to ensure that international trade in specimens of wild animals and plants does not threaten the survival of the species in the wild, and it accords varying degrees of protection to more than 35,000 species of animals and plants.
The Endangered Species Act of 1973 it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and development." The U.S. Supreme Court found that "the plain intent of Congress in enacting" the ESA "was to halt and reverse the trend toward species extinction, whatever the cost.“
The Marine Mammal Protection Act of 1972 (MMPA) was the first act of the United States Congress to call specifically for an ecosystem approach to natural resource management and conservation. MMPA prohibits the taking of marine mammals, and enacts a moratorium on the import, export, and sale of any marine mammal, along with any marine mammal part or product within the United States. The Act defines "take" as "the act of hunting, killing, capture, and/or harassment of any marine mammal; or, the attempt at such." The MMPA defines harassment as "any act of pursuit, torment or annoyance which has the potential to either: a. injure a marine mammal in the wild, or b. disturb a marine mammal by causing disruption of behavioral patterns, which includes, but is not limited to, migration, breathing, nursing, breeding, feeding, or sheltering."
Whale Conservation and Protection act 1976, International Convention on Biological diversity 1995.

54. Economic Incentives to Protect Aquatic Biodiversity
For example: Sea turtle tourism brings in 3 times more money than does the sale of turtle meat, leather and eggs.
Some people still take turtles to make a quick buck not seeing the deeper value of keeping them alive. Education about turtle value may help communities protect the turtles.
By international law a country has control over their shoreline waters that extends 370 km (200 miles) from shore. Ocean water further out is considered high seas. Many countries have set up marine protected areas, sanctuaries and reserves in these waters to help protect marine species. Their goal is to reduce fishing in these areas and increase biodiversity.
Environmental mitigation describe projects or programs intended to offset known impacts to an existing historic or natural resource such as a stream, wetland, endangered species, archeological site or historic structure. To "mitigate" means to make less harsh or hostile. Environmental mitigation is typically a part of an environmental crediting system established by governing bodies which involves allocating debits and credits. Example: Allowing destruction of an ecosystem if a ecosystem of equal value is created somewhere else.

55. Reconciliation ecology is the branch of ecology which studies ways to encourage biodiversity in human-dominated ecosystems. Michael Rosenzweig first articulated the concept in his book Win-Win Ecology, based on the theory that there is not enough area for all of Earth’s biodiversity to be saved within designated nature preserves. Therefore, humans should increase biodiversity in human-dominated landscapes. By managing for biodiversity in ways that do not decrease human utility of the system, it is a “win-win” situation for both human use and native biodiversity.
A simple form of reconciliation ecology: the construction of nest boxes increases densities of bluebirds in areas where natural tree cavities are scarce due to short-rotation forestry
Any business that cooperates with local conservation efforts is practicing reconciliation ecology.

56. About 75% of the commercial fisheries are fished beyond their estimated sustainable yields. When an area is no longer profitable to fish because of overfishing it is termed commercially extinct.

57. The benefits of working with nature’s water cycle,
rather than further disrupting it,
are too compelling to ignore.
SANDRA POSTEL

58. Is There Enough Water? (13)
Freshwater is being managed poorly: We waste it and pollute it.
Freshwater is of major importance to all living things; in some organisms, up to 90 percent of their body weight comes from water. Up to 60 percent of the human body is water, the brain is composed of 70 percent water, and the lungs are nearly 90 percent water. About 83 percent of our blood is water, which helps digest our food, transport waste, and control body temperature. Each day humans must replace 2.4 liters of water (1/2 a gallon), some through drinking and the rest taken by the body from the foods eaten.
The United States in 2000, the per capita average had declined to about 1,430 gallons per day per person (Largest per capita in the world). The lowest per capita use occurs in Africa. Most of that water is used for agriculture. For industry most of the water is used for cooling electrical power plants. The demand for water is twice as high as the human growth rate.

59. Water keeps us alive, moderates climate, sculpts the land, removes and dilutes wastes and pollutants, and moves continually through the hydrologic cycle.
We are using available freshwater unsustainably by wasting it, polluting it, and charging too little for this irreplaceable natural resource (Most waste comes from how cheap water is).
Access to water is
1. A global health issue: One of every six people does not have sufficient access to clean water, and this situation will almost certainly get worse. The WHO estimates that 1.6 million people die form waterborne diseases each year (90% children)
2. An economic issue: Vital for reducing poverty, growing food and producing energy.
3. A women’s and children’s issue: They are usually tasked with finding and carrying water.
4. A national and global security issue: Tension in the Middle East for shared water resources.
5. Environmental issue: Excessive withdrawal of water from rivers and aquifers and pollution of water result in a lower water table, shrinking rivers and lakes, loss of wetlands, loss of fish, etc.
Only about 0.024% of the earth’s water supply is available to us as liquid freshwater (the rest is salty, frozen or deep in the Earth). Fortunately the hydrological cycle collects and purifies the freshwater supply.

61. Ground and Surface Water
Some precipitation infiltrates the ground and is stored in soil and rock (groundwater).
Water that does not sink into the ground or evaporate into the air runs off (surface runoff) into bodies of water.
A drainage basin or watershed (North American English usages) is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point at a lower elevation, usually the exit of the basin, where the waters join another water body, such as a river, lake, reservoir, estuary, wetland, sea, or ocean.
These water bodies supply our drinking water, water for agriculture and manufacturing, reduce flooding, offer opportunities for recreation and provide habitat to numerous plants and animals. Unfortunately various forms of pollution, including runoff and erosion, can interfere with the health of the watershed.

62. Groundwater
The soil close to the Earth’s surface hold little moisture. Below a certain depth (varies from place to place) is the zone of saturation where the spaces between the soil particles are completely filled with water. The top of this zone is the water table, which fluctuates throughout the year.
Deeper down are underground water storage areas called aquifers. An aquifer is an underground layer of water-bearing permeable rock or unconsolidated materials (gravel, sand, or silt) from which groundwater can be extracted using a water well. Groundwater is one of our most important sources of freshwater.
Renewability – the circulation rate of groundwater is slow (300 to 4,600 years). Groundwater flows very slowly typically about 1 meter or 3 feet per day.
Groundwater recharge is a hydrological process where water moves downward from surface water to groundwater. Groundwater is recharged naturally by rain and snow melt and to a smaller extent by surface water called lateral recharge (rivers and lakes).
Recharge area is the area of permeable soil that allows water to percolate to the water table to replenish the groundwater supply.

63. Aquifers
An unconfined aquifer is an aquifer with a permeable water table. A confined aquifer is bounded above and below by less permeable beds of rock where the water is confined under pressure. Some aquifers are replenished by precipitation; others are not.

64. Human Impact on Groundwater
Human impact groundwater in several ways:
Aquifer depletion
Loss of recharge area: Covering natural soil with pavement and buildings (urbanization), which inhibits the ability of water to reach the water table.
Logging: Destabilizes soil causing runoff of water not absorption.
Sinkholes form when the roof of an underground cavern collapses after being drained of groundwater.
Contamination/pollution
A. Coliform bacteria: The W.H.O. recommends there be zero colonies of bacteria per 100ml of drinking water and 200 colonies per 100ml of swimming water. The average human excretes 2 billion organisms per day (see how easily untreated sewage can contaminate water?).

65. Saltwater intrusion is the movement of saline water into freshwater aquifers, which can lead to contamination of drinking water sources and other consequences. Saltwater intrusion occurs naturally to some degree in most coastal aquifers. Because saltwater has a higher mineral content than freshwater, it is denser and has a higher water pressure. As a result, saltwater can push inland beneath the freshwater. Certain human activities, especially groundwater pumping from coastal freshwater wells, have increased saltwater intrusion in many coastal areas. Water extraction drops the level of fresh groundwater, reducing its water pressure and allowing saltwater to flow further inland.

66. Ogallala Aquifer
This is the world’s largest known aquifer, and fuels agricultural regions in the U.S. It extends from South Dakota to Texas. It’s essentially a non-renewable aquifer from the last ice age with an extremely slow recharge rate. In some cases, water is pumped out 8 to 10 times faster than it is renewed. Northern states will still have ample supplies, but for the south it’s getting thinner. It is estimated that ¼ of the aquifer will be depleted by 2020.
The Ogallala, the world’s largest aquifer, is most of the red area in the center (Midwest).
Areas of greatest aquifer depletion from groundwater overdraft in the continental U.S.

68. Surface Water
Surface water is the freshwater from precipitation and snow melt that flows across the Earth’s surface and into rivers, streams, lakes, wetlands, estuaries and ultimately into the ocean.
Any water that does not infiltrate the land or return to the atmosphere by evaporation is called surface runoff. Surface runoff is stored in watersheds or drainage basins.
Reliable surface runoff is the water that humans can generally relay on as a source of freshwater from year to year. Only 1/3 of the seasonal precipitation is reliable (the other 2/3 is lost in floods.
We currently use more than half of the world’s reliable runoff of surface water and could be using 70-90% by The per capita water withdrawal has quadrupled in the last century.
About 70% of the water we withdraw from rivers, lakes, and aquifers is used for irrigation of crops and not returned to these sources. Industry uses 20% and cities the remaining 10%.

69. Water Shortages Will Grow
Major factors contributing to growing water shortages:
1. Living in dry climates
2. Drought: a prolonged period of time where precipitation is at least 70% lower and evaporation is higher than normal.
3. Too many people using the reliable water supply.
4. Wasteful use of water. We waste water because it is so cheap.
There are water wars out west. California bought the water from the Colorado River, but Arizona wants it. Who owns it? The same thing is happening in Texas. More water rights are sold than the actual amount of water. How do you share water? This is a problem all over the world.

70. Surface Water Problems in the U.S.
The polluted Mississippi River (non-source point pollution) Stretches of the Mississippi River exceed water quality standards for mercury, bacteria, sediment, PCBs (polychlorinated biphenyl), and nutrients. Unfortunately, these "impairments" can make the water unsuitable for fishing, swimming, and drinking.
In the Eerie Canal, which connects the ocean to the Great Lakes, lampreys came in and depleted the fish. The zebra mussel is also a problem in the Great Lakes. These introduced species compete more effectively and reduce or eliminate native species.

71. Overdrawing Surface Water
Lake levels drop, recreation use drops, fisheries drop, and salinization occurs.
Ex. Soviet Union (Aral Sea); Formerly one of the four largest lakes in the world with an area of 68,000 km2 (26,300 sq mi), the Aral Sea has been steadily shrinking since the 1960s after the rivers that fed it were diverted by Soviet irrigation projects. By 2007, it had declined to 10% of its original size, splitting into four lakes .
About 85% of the wetlands have been eliminated and roughly 50% of the local bird and mammal species have disappeared.
Since 1961, the sea’s salinity has tripled and the water has dropped by 22 meters most likely causing 20 of the 24 native fish species to go extinct.

72. California’s Water Demand
WATER PROJECTS AND THE STATE'S ECONOMY
Water development has three primary goals: flood control, water storage, and hydroelectric power generation. California is home to four massive water projects, plus numerous local projects. The map to the right shows the water projects located throughout the state. The Los Angeles Aqueduct brings water from the Owens Valley south to Los Angeles. The Colorado River Aqueduct brings water from the Colorado River to Southern California for urban uses.
Moving water around the state is an energy intensive process. Total energy used to pump and treat water accounts for at least 6.5% of total electricity used statewide. Hydroelectric power does produce a portion of this energy back, but whether the project is a net user or net producer of energy depends upon the distance the water must be moved. In most cases, more energy is used than is produced by these projects.

73. The Colorado River Basin
These are dams & reservoirs that feed from the Colorado River all the way to San Diego, LA, Palm Springs, Phoenix & Mexico. So far has worked because they haven’t withdrawn their full allocations.
The area drained by this basin is equal to more than one-twelfth of the land area of the lower 48 states.
The Colorado River has so many dams and withdrawals that it often does not reach the ocean.
Glenn Canyon Dam: hydroelectric plants located on the Colorado River
14 major dams and reservoirs, and canals. Provides electricity from hydroelectric plants for 30 million people (1/10th of the U.S. population).
Water is mostly used in desert areas of the U.S.
Lake Powell, is the second largest reservoir in the U.S.
Glen Canyon Dam

74. Lake Mead is the largest reservoir in the United States in maximum water capacity. It is located on the Colorado River about 24 mi (39 km) from the Strip southeast of Las Vegas, Nevada, in the states of Nevada and Arizona. Formed by the Hoover Dam, Lake Mead holds 28 million acre-feet (35 km3) of water, when filled to capacity. However, the lake has not fully reached this capacity since 1983 due to a combination of drought and increased water demand.
Dams are structures built across rivers to control water flow. A dam creates an artificial lake called a reservoir. Building a dam and reservoir systems has greatly increased water supplies in some areas, but it has disrupted ecosystems and displaced people.

75. Provides water for year-round irrigation of cropland
Flooded land destroys forests or cropland and displaces people
Large losses of water through evaporation
Provides water for drinking
Downstream cropland and estuaries are deprived of nutrient-rich silt
Reservoir is useful for recreation and fishing
Risk of failure and devastating downstream flooding
Can produce cheap, renewable electricity (hydropower)
Downstream flooding is reduced
Migration and spawning of some fish are disrupted
Fig a, p. 317

76. Power lines
Reservoir
Dam
Powerhouse
Intake
Turbine

77. Building Dams China’s Three Gorges Dam
The Three Gorges Dam is a hydroelectric dam that spans the Yangtze River. The Three Gorges Dam is the world's largest power station. As well as producing electricity, the dam is intended to increase the Yangtze River's shipping capacity and reduce the potential for floods downstream by providing flood storage space.
There is a debate over whether the advantages of the world’s largest hydroelectric dam and reservoir will outweigh its disadvantages.
1. The dam is be 2 kilometers long.
2. The electric output is that of 18 large coal-burning or nuclear power plants.
3. It facilitates ship travel reducing transportation costs.
4. Displaced 1.2 million people.
5. Dam is built over seismic fault and already has small cracks.

78. The James Bay Project refers to the construction is a series of hydroelectric power stations on the La Grande River in northwestern Quebec.
Environmental impacts
Mercury pollution: Boreal forest (taiga) became flooded and this flooded vegetation's stored mercury (Hg) that was released into the aquatic ecosystem
Local climate changes: The establishment of reservoirs containing large amounts of standing water has the ability to produce local climate changes
The Aswan High Dam is an embankment dam situated across the Nile River in Aswan, Egypt.
The High Dam has resulted in protection from floods and droughts, an increase in agricultural production and employment, electricity production and improved navigation that benefits tourism. Conversely, the dam flooded a large area, causing the relocation of over 100,000 people and submerged archaeological sites, some of which were relocated as well. The dam is also blamed for coastline erosion, soil salinity and health problems.

79. Desalination
Desalination refers to any of several processes that remove some amount of salt and other minerals from saline water. It is currently for water short, wealthy countries that can afford it.
Distillation: heating saltwater until it evaporates, leaves behind salt in solid form.
Reverse osmosis: uses high pressure to force saltwater through a membrane filter that is small enough to capture salt.
The resulting salty brine must be disposed of without harming aquatic or terrestrial ecosystems.
Salt water is desalinated to produce fresh water suitable for human consumption or irrigation. One potential byproduct of desalination is salt. Desalination is used on many seagoing ships and submarines. Most of the modern interest in desalination is focused on developing cost-effective ways of providing fresh water for human use. Along with recycled wastewater, this is one of the few rainfall-independent water sources.
Due to relatively high energy consumption, the costs of desalinating sea water are generally higher than the alternatives (fresh water from rivers or groundwater, water recycling and water conservation), but alternatives are not always available.
Due to having the least amount of naturally occurring freshwater per capita, the Middle East uses desalination to supply much of their freshwater needs. The world's largest desalination plant is the Jebel Ali Desalination Plant in the United Arab Emirates. The largest percent of desalinated water used in any country is in Israel, which produces 40% of its domestic water use from seawater desalination. Australia, which traditionally have relied on collecting rainfall behind dams to provide their drinking water supplies is turning to desalination.

80. James Bay
Glenn Canyon Dam
Three Gorges Dam
Asia
Europe
North America
Hoover Dam
Africa
South America
Australia
Stress
High
None
Major desalinization
Aswan High Dam

81. Reducing Water Wastes
65-70% of the water people use throughout the world is wasted through evaporation, leaks and other loses. The United States is the largest user of water and loses about 50% of the water it withdraws.
The main cause of water waste is its low cost to users. By subsidizing water governments:
1. Little or no incentives to invest in water saving technologies.
2. Gives a false message that water is abundant and can afford to be waster.
3. Homeowners are not as quick to fix a leak or broken sprinkler.
We can use water more sustainably by cutting water waste, raising water prices, slowing population growth, and protecting aquifers, forests, and other ecosystems that store and release water.

82. Cut Water Waste in Irrigation
Agricultural practices must be used in order to minimize water loss, runoff and evaporation.
Irrigation is the artificial application of water to the land or soil.
Center pivot
(efficiency 80% with low-pressure sprinkler and 90–95% with LEPA sprinkler)
Drip irrigation
(efficiency 90–95%)
Gravity flow
(efficiency 60% and 80% with surge valves)
Above- or below-ground pipes or tubes deliver water to individual plant roots. The most effective way to conserve water.
Water usually pumped from underground and sprayed from mobile boom with sprinklers.
Water usually comes from an aqueduct system or a nearby river.

84. Flooding
Heavy rainfall, rapid snowmelt, removal of vegetation, and destruction of wetlands cause flooding.
Floodplains, which usually include highly productive wetlands, help provide natural flood and erosion control, maintain high water quality, and recharge groundwater.
To minimize floods, rivers have been narrowed with levees and walls, and dammed to store water.
Comparison of St. Louis, Missouri under normal conditions (1988) and after severe flooding (1993).

85. We can lessen the threat of flooding by protecting more wetlands and natural vegetation in watersheds and by not building in areas subject to frequent flooding.

87. How can you conserve water?
Reduce the length of showers
Shower less frequently
Install low flow shower heads and toilets
Make sure all water leaks are fixed
Turn off water while brushing your teeth
Run dishwasher or washing machine only when full
Use water efficient appliance
Hand wash dishes
Use paper plates and plastic silverware that don’t need a dishwasher
Use plants outside that require little watering (drought tolerant), only water on alternate days, use drip irrigation
Sweep sidewalks and driveways instead of spraying them down
Turn off water while washing car or wash car less often

88. How do we conserve energy?
Turn off electric appliances when no one is in the room
Turn off lights in daylight hours
Replace incandescent light bulbs with fluorescents
Increase insulation
Set thermostats higher in summer and lower in winter
Use an automatic thermostat that lowers/raises temperatures when no one is in the house
Replace appliances with energy-efficient appliances
Open windows and use fans instead of air-conditioning
Hand wash dishes as not to use dishwasher
Line dry clothing instead of using dryer
Use sweaters and blankets instead of using the heater
Caulk and weather strip exterior doors and windows