Chapter 6

World Forests

• Boreal and Tropical Forests Are Most Abundant
• Forests Provide many Valuable Products
• Many Forests Are Being Cleared Rapidly

Ø  Cause of Deforestation

Ø  Forest Protection

• Temperate Forests Are Also At Risk

Ø  Old-Growth Forests

Ø  Harvesting Methods

Ø  Roads and Logging

Ø  Fire Management

Ø  Ecosystem Management

Grasslands

• Grazing Can Be Sustainable or Damaging
• Overgrazing Threatens Many Rangelands
• Ranchers Are Experimenting With New Methods

Parks and Reserves

• Many Countries Have Created Nature Preserves
• Not All Preserves Are Preserved
• Marine Ecosystems Need Greater Protection
• Conservation and Economic Development Can Work Together
• Native People Can Play Important Roles In Nature Protection
• Special Survival Can Depend On Preserve Size and Shape

Boreal and tropical forests are most abundant

Most of the remaining forests are in cold boreal, taiga regions, and humid tropics. What is a forest, according to the (FAO) any area where trees cover more than 10 percent of the land. A closed-canopy forest is where tree crowns cover most of the ground below. Many of these forests have been destroyed with the highest rates of forest destruction in Africa, but there are other areas also being deforested like in Southeast Asia and Central America. Forests hold more than 422 billion metric tons of carbon but when these forests are cut down or burned many of these carbons are released into the atmosphere. Studies done recently have suggested that much of the deforestation in the amazon could affect the American Midwest in the form of perspiration. The greatest forests in the world are the old-growth forests as they have the greatest ecological remnants much of this is due to the fact that most of the forest has been undisturbed by humans and if they have been disturbed it’s to a very same degree. Forest cover about half of what they did a one point worldwide, but worst is that only one third of these forests are old-growth forests.

Forests provide many valuable products

Wood is the most important commodity as it is used in more activities of the modern economy than any other. Wood consumption is at 4 billion m3 which is more than plastic and steel combined. “International trade in wood and wood products amounts to more than $100 billion each year” (Cunningham & Cunningham). Developed counties in North America, Europe, and Asia use the most wood accounting for 80 percent of its consumption. While less developed countries only use the other twenty percent but produce more than half of the wood production. Global demand for wood is causing deforestation in Southeast Asia, West Africa, and other regions around the world. A problem is begging in the fuel wood area as more two billion people depend upon it and the number is growing. Fuel wood is slightly less than the global population growth rate. Fuel wood (firewood) is become one of the main reasons for deforestation. While there are many countries that have begun to replant forests, there is a major flaw as much of the planting is of one spice making these forests monoculture forests. While these kinds of forests are rapid growing forests and make for easier harvesting they don’t support a diverse ecosystem and do little to control soil erosion. Two countries that have had successful reforestation programs are Korea and Japan which are both know 70 percent forested.

Infra-red photo from space 1992 - rainforest is red

Infra-red photo from space 2006 - rain-forest is red

Tropical forests are being cleared rapidly

Of all the forest a tropical forest is the most diverse ecosystems in the world. Thought, they only occupy about 10 percent of the world’s surfaces they contain two-thirds of the higher plant biomasses and at least half of the plant, animal, and microbial spices in the world. These forest have been cut down over the centuries and a century ago there was more than 12.5 million km2 of them around the world. While many argue on the term deforestation whether it is a clearing, complete change, and others include any area that has been logged selectively. With all of this in mind there are different numbers on deforestation which range from 5 to 20 million ha per year, but the FAO estimates that 10 million ha deforested which is considered the most widely accepted.

                Causes of deforestation

Deforestation is caused by things whether it’s for firewood or paper products and especially in tropical forests it’s for the hardwoods such a teak and mahogany which is very valuable compared to other woods. “Logger’s may take only one or two of the largest trees per hectare, the canopy of tropical forests is usually so strongly linked by vines and interlocking branches that felling one tree can bring down a dozen others” (Cunningham & Cunningham). The building of roads in the forest is very destructive to the forest not just that it kills many more trees, but also allows access to farmers, miners, hunters, and many others that can cause further damage to the environment. When forests are cut down rainfall patterns can change and rainfall decreases. “The tiny island-nation of Nauru in the western Pacific is the smallest and most remote republic in the world. It also is a case study in humanity's ability to plunder its environment” (Administrator, 2007). This study shows the effects of destroying your environment for a natural element in your environment and the effects it has on the environment.  

                Forest protection

While much of the news about forest is not good there is hope as many countries are starting to see that forests are valuable resources and should be protected. Only about 14 percent of the world’s forests are protected in some form, but there are more and more efforts being made to increase this number every year. Dan Janzen stated that “One of the keys to success is involving local people in the project” (Cunningham & Cunningham). Dan is a worker in Guanacaste, Costa Rica working to reforest the topical forests in Costa Rica. During the 2009 Copenhagen Climate Conference an agreement in principle to fund the REDD program. What is the REDD program? It is a program that works to protect forests and restoring forests and while REDD the program won’t start until 2013 there have been several new programs around the world to help forests.

Temperate forests also are at risk

While tropical forests are being cut down there are also temperate forests that are being cut down at the same time around the world. If you look at the U.S. Forest Service which has an official policy of “multiple use” which by many implies that you can do many things with a forest that can be bad for the actual forest and its ecosystem.

                Old-growth Forests

Most of the contentious battles in Canada and United States have been about old-growth forests on whether to allow or ban logging in these forests. One of the main reasons to protect these old-growth forests is because they protect some of the most endangered species in the world from the northern spotted owl, vaux’s swift, and the marbled murrelet, many of the animals are so adapted to their environment that they would not live anywhere else. The U.S. Northwest forest management plan attempts to integrate human and economic dimensions in forests while also protecting forests, wildlife, and waterways for long-term health. The plan uses scientific studies along with legal responsible strategies to implement new plans. These plans and retractions in recent history have help many spices are still becoming endangered such as the salmon steelhead trout.

                Harvesting methods

Many of the United States lumber and pulpwood is harvested in a clear-cutting faction. Clear-cutting is where every tree in given area is cut down, regardless of the size of the tree. The problem with clear-cutting is that it causes erosion to the soil and destroys habitats for animals. There are alternatives to clear-cutting one of them is shelter-wood harvesting. This harvesting technique takes the mature trees. Another technique is strip-harvesting; this is where a narrow area of trees is harvested. Finally there is selective cutting which is the least destructive to the forest. This technique is where a percent of the mature trees are cut down in 10-20 year rotations.

                Roads and logging

Many people in America want to have logging banned on federal land, of course there is several people opposed to this as it work take away most of the logging jobs. There is also the people that feel that logging should only be done on private owned land. The wood harvested in America 4 percent is harvested in national forests which have many people upset, and the fact that it only contributes $4 billion to the economy whereas recreational events in national forests contribute $224 billion to the economy. Roads in National Forests have increased tenfold in the past 40 years mainly for logging. The total number of land now used for roads is 343,000 mi.

                Fire management

 During the 1930s there were a series of massive fires that destroyed millions of hectares of forests. The Forest Service started a new policy to combat fire by not allowing a fire to burn past 10 am they also created Smokey the bear. The policies did help but new studies show that biological communities adapt to fire and need it for regeneration. There is also the fact that many forests have massive amounts of fire starters like pine needles, pine cones, dead leafs, and other material that burn quickly, that if a fire were to start in these forests they would be big fires. “The U.S. Forest Service estimates that 73 million acres, or about 40 percent of all federal forestlands, are at risk of severe fires” (Cunningham & Cunningham). There is also the fact that many 40 million Americans now live in high risk wildfire areas.

                Ecosystem management

Federal agencies in the 1990s changed form an economic policy to an ecosystem management. There new principals include: manage areas with ecological time scales. Make decisions with dependable scientific data. Consider the needs of humans and make sure to promote economic and communities. Keep diversity in biological areas while maintaining ecosystem process. Always look to have cooperative institutional arrangements. Involve the public and facilitate collective decision making. Make management be looked at overtime through experimentation and routine monitoring. There are always critics of anything many argue that we don’t have enough knowledge of ecosystems that we can’t make decisions on something that we don’t have enough information on.

Grazing can be sustainable or damaging

When ranchers, and pastoralists use conscientious to manage their animals it can help improve the range. The facts show the opposite thought that many are not moderating or don’t have anywhere else to move their herds causing overgrazing. Nearly three-quarters of all rangeland in the world shows signs of either degraded vegetation or soil erosion, and one-third is due to overgrazing. There are people that have taken on this change and are reclaiming deserts and repairing the effects of neglect and misuse.

Rangeland degradation since 1945

Overgrazing threatens many rangelands

Politics and economics have caused many of the ranges around the world to be overgrazed. There are statistics that claim that rangelands in America are badly overgrazed as 30 percent are in fair condition and that 55 percent are in poor or very poor condition. Overgrazing has caused many plants like sage, mesquite, cheat grass, and cactus to grow rapidly. Many people want grazing on public land banned because cattle and sheep stating that only 2 percent of the total forage consumed by beef cattle and supports only 2 percent of all livestock producers. There is also the fact that the 31,000 permits for range grazing only produce $11 million while it costs $47 million for maintenance of these permits.

Ranchers are experimenting with new methods

Cattle and sheep tend to eat only the tender, best tasting grass leaving the tough, unpalatable species to flourish. There are different things ranchers do now one is called rotational grazing where you confine the heard to a small area for a short time. Another is to have the livestock eat everything equally, to trample the ground thoroughly with the own herds manure helps to keep weeds in check. This doesn’t work everywhere especially in U.S. deserts of the southwest. As fire can help in forests it can also help grasslands too. Another approach ranchers are doing is raise wild spices like impala, wildebeest, deer, and elk as these animals eat less and will eat a wider variety of plant materials. Many of these animals have leaner meat often getting a better finical return than with beef.

131 priority conservation areas in Arizona which harbor almost 600 species

Many countries have created nature preserves

There are five different categories for protected areas separated on the human use or presence. The five one is cultural which allows for medium to high human impact. The four is habitat and wildlife which allows for medium human impact. The third is natural monuments and archaeological sites, which allows low to medium human impact. The second one is national parks which allow low human impact. Finally the first one is ecological reserves which allow little to no human impact. Many countries have begun to protect their environments whether it is five level of protection or number one it is still a step in the right direction.

Not all Preserves are preserved

Even areas with high designated protection are being changed whether it is political or exploitation. In Greece a new hydroelectric dam is being planned to be built in the middle of the park and with excessive stock grazing and forestry exploitation are causing erosion and loss of wildlife. Many developing countries don’t have the needed funds to protect their parks or protected areas. Even developed countries are having a hard time at it too, thought, the united states for example is having problems in popular parks like Yellowstone and the grand canyon as to many people are in the parks causing problems with crowds and pollution. There is also the fact that many parks used to and some still do but most don’t allow or encourage to feed wildlife. Some parks even changed their environments like Yellowstone and Teton National Parks which allowed elk to grow to 25,000 animals or about twice the amount the environment can support. Some new rules in parks are created due to these problems some have banned private automobiles and some parks are even considering limiting the number of visitors admitted in a day. 13 U.S. National Monuments are open to oil and gas drilling. U.S. National Park System which is underfunded and maintenance is backlogged to an estimated five billion dollars. IUCN has developed a world conservation strategy which has three objectives: (1) maintain ecological processes and life-support systems; (2)preserve diversity for breeding and improve cultivated plants and domestic animals; (3) ensure that any utilization of wild species and ecosystems is sustainable.

Marine ecosystems need greater protection

Ocean fish stocks are become increasingly depleted every year. Many biologists are calling for protected areas, and although about 14 of land area is protected there is only 5 percent of near shore marine biomes are protected. One why that has helped replenish fish stocks is by limiting the kinds of fishing techniques. Because 90 percent of all coral reefs face threats from rising temperatures, fishing techniques, and human disturbances, marine biologists are calling on nations to protect 20 percent of their near shore territories as marine refugees. Australia has one of the largest marine reserves at 344,000 km2. President G. W. Bush declared more than 505,000 km2 of ocean and pacific islands as national monuments.

Conservation and economic development can work together

Many developing countries in the world have the most biologically rich communities many of these are in the tropics. Many people in these countries are poor and look to anything whether it is good or bad for the environment to meet their own needs. Some people see that there are ways to protecting the environment but still making a profit off it with ecotourism which means tourism that is ecologically and socially sustainable for the long term environment.

Native people can play important roles in nature protection

Many important biomes have aboriginal people and a have a legitimate right to purse traditional life. Of the 5,000 native cultures many possess ecological knowledge, which can be valuable for ecosystem management. Some countries have taken many native people from these parks which can be very useful for protecting wildlife against pouters as guards are often at the forests. There is a down side, thought, as native can also be killed for simply trying to return home or collect fire wood or hunt for small game. The UNESCO initiated the man and biosphere program which encourages the designation of biosphere reserves. A good example of a biosphere reserve is in Mexico the Sian KA’an reserve which has many rare spices but also has about 25,000 people.

Species survival can depend on preserves size and shape

Parks around the world are shrinking yet many are looked to become more and more important ofr maintaining biological diversity. Many conservation biologists have disputed on whether a single large or several small reserves is better for spices. Ideally a reserve should be large enough to support populations of endangered spices. Some spices with small territories can have viably population in small reserves. One solution to small habitats is corridors which connect other small habitats with each other by. How well a corridor works is mainly on the fact of how big it is and how long it is. Many feel though that a large reserve is best as it with have a core habitat, which is deep in the reserve that has better conditions for specialized species. Edge effects are the edges of the reserve that might have open areas of wooded areas which are not good for the species as they are used to a different kinds of an environment usually different than that found on the edges of the reserve.           

Chapter 7 

Global Trends in Food and Nutrition

• Food Security is Unevenly Distributed

• Famines Usually Have Political and Social Roots

How Much Food Do We Need?

• A Healthy Diet Includes the Right Nutrients

• Overeating is a Growing World Problem

• More Production Doesn’t Necessarily Reduce Hunger

What Do We Eat?

• Rising Meat Production is a Sign of Wealth

• Seafood is Both Wild and Farmed, But Not Nearly All Depends On Wild-Source Inputs

• Biohazards Can Arise In Industrial Production

Living Soil Is a Precious Resource

• What is Soil?

• Healthy Soil Fauna Can Determine Soil Fertility 

• Your Food Comes Mostly From the A Horizon

The Uneven Distribution of Food Security

Over the last 50 years, the world's population has risen from three billion to about seven billion and food production has increased even faster. However, hunger is still with us. Approximately one in every eight people on earth suffers chronic hunger and about 95% of the hungry people are in developing countries. The ability to obtain sufficient, healthy food on a day-to-day basis, or food security, is not available in some regions of the world, especially in sub-Saharan Africa. These problems are made further worse because of economic, environmental and social conditions. This problem is not just in poor countries, however. Wealthy countries also have millions who lack a sufficient, healthy diet. Women and children suffer the most with at least 6 million children under 5 years old dying every year from diseases exacerbated by hunger and malnutrition. 

The Political and Social Roots of Famines

Large-scale food shortages or famines can cause widespread starvation, social disruption and economic chaos. In an attempt to keep themselves alive, people will eat their seed grain and slaughter their breeding livestock. Famines also start mass migrations to relief camps, where people survive but cannot maintain a healthy and productive life. There is a correlation between corrupt governments and farmers who are unable to survive. Armed conflict and political oppression are almost always at the root of famine and no democratic country with a relatively free press has have had a major famine. 

The Right Nutrients Promote a Healthy Diet

A nutritional imbalance caused by a lack of specific nutrients is called malnourishment. A lack of protein in a young child can cause kwashiorkor, which causes a bloated belly and discolored hair and skin.  Another severe condition in children lacking protein and calories is marasmus. Children who suffer from this are generally thin and shriveled. Children who have these deficiencies are more susceptible to disease and infections and may also suffer mental and physical development. Other important nutritional needs are vitamin A, folic acid and iodine. These deficiencies can cause blindness and cause goiters on the thyroid gland. Our bodies need lots of vegetables, grains, moderate amounts of eggs and dairy products and sparing amounts of meat, oils and processed foods to stay healthy. “Every year more than a million children die and another 350,000 go blind from the effects of vitamin A deficiency” (Administrator, 2012). This study looks at the inventions of “Golden rice” which can help people with vitamin A deficiency.

 

Growing World Problem of Overeating

There are probably more overweight people than underweight people in the world, and not just in richer countries. Europe, the US, China and developing countries have more highly processed foods rich in sugars and fats in their diets. About one third of adults Americans are obese, which is generally considered to mean they are more than 20 percent over their ideal weight. There are many diseases that are increased by being overweight including respiratory problems, osteoarthritis, gallbladder disease, stroke, heart attacks, hypertension and diabetes. A contribution to being overweight can also be poverty and not having the proper, good quality foods that make up a healthy diet. 

Hunger Not Necessarily Reduced by More Production

Increasing efficiency of farm production, expanding use of fertilizers and improved seeds, and converting more unused land or forest to agriculture are some strategies for reducing world hunger.  However, an overabundance of food supplies in much of the world suggests that answers to global hunger may lie in better distribution of food resources. 

Increased Meat Production is a Sign of Wealth

The high-value source of protein, iron, fats and other nutrients, meat gives us the energy to lead productive lives. Dairy is also a key protein; however, dairy production per capita has declined slightly while meat productions have doubled in the past 45 years. It is expensive to produce meat, in terms of the resources needed to nourish the animal. Increased production is also possible because of technological and breeding innovations. One of the most important innovations is the confined animal feeding operation, or CAFO, where animals are housed and fed, mainly soy and corn, for rapid growth. Antibiotics in the animal feed make it possible to house and raise large numbers of animals in close quarters.

Seafood Dependent on Wild-Source Inputs

Seafood provides about 15 percent of all animal protein eaten by humans, is a main animal protein source for about 1 billion people in developing countries and is just part of the 140 million metric tons we eat every year. There is a decline in the world's edible ocean fish, crustaceans and mollusks which is making managed conservation a need. Fishing by dragging large nets sweeps the ocean and scoops up everything along its way. An increasing share of the world’s seafood is being provided by aquaculture. The highly productive farm ponds take relatively little space and produce fish like tilapia, which is a plant-eating fish. 

Biohazards can Arise in Industrial Production

With increased and efficient production, there are some externalized and unaccounted for costs in terms of public health. Bacteria in the manure of feedlots or liquid wastes in manure storage lagoons can breach the walls of the manure tank. When Hurricane Floyd hit North Carolina's coastal hog production region in 1999, the waste overflowed into local rivers and caused a dead zone in the Pamlico Sound. Antibiotics administered to livestock are creating antibiotic-resistant diseases. This massive and constant exposure produces antibiotic-resistant pathogens, strains that have adapted to survive antibiotics. This is changing our standard health care for humans as more and more diseases are antibiotic resistant. We are willing to accept these risks because the production makes meat cheaper and more available. 

Soil

There are six components of soil including sand and gravel; silts and clays; dead organic material; soil fauna and flora; water; and air. The variety of the world’s soils depends on the variations of these six components. Depending on the makeup of the soil, it may be rich for growing or sandy and easily drained of moisture. The make-up of the soil also makes the soils different colors and gives us a clue as to what the soil is made up of. 

Soil Fertility dependent on Healthy Soil Fauna

Environmental conditions will determine the health of the soil. These include climate, topography and parent material and frequency of disturbance. Soil fauna needs moisture to survive but too much rain will wash away nutrients and organic matter. Most soil fauna occur in the uppermost layers of a soil, where they consume leave litter. This layer is known as the organize horizon. Below the organize horizon is a layer of mixed organic and mineral soil material, the A horizon or surface soil. The subsoil, or B horizon, lies below most organic activity and tends to have more clays than the A layer. A handful of B soil should hold its shape better than a handful of a soil. The E layer, which lies between the A and B horizons, is a washed out layer that is loose and light colored because most of its clays and organic material have been washed down to the B horizon. Below the subsoil likes the C horizon which is mainly decomposed rock fragments. Under the C layer lays the parent materials which is the sand, wind-blown silt, bedrock or other mineral on which the soil is built. 

A Horizon provides most of our food

The rich black A horizon is ideal farming soil because it is organic-rich. Topsoil is important to our survival and we differentiate soils largely according to the thickness and composition of the upper layers. Thousands of different soils types have been classified by the U.S. Department of Agriculture and we find that the Mollisols, a thick organic-rich A horizon and the alfisols, are slightly thinner A horizon with slightly less organic matter, dominates mort of the farming regions of the United States. 

      

Chapter 10

Water Resources

• The Hydrologic Cycle Constantly Redistributes Water

Major Water Compartments

• Glaciers, Ice, and Snow Contain Most Surface, Fresh Water

• Groundwater Stores Large Resources

• Rivers, Lakes, and Wetlands Cycle Quickly

• The Atmosphere Is One of the Smallest Compartments

Water Pollution

• Pollution Includes Point Sources and Nonpoint Sources

• Biological Pollution Includes Pathogens and Waste

Ø  Pathogens

Ø  Biological Oxygen Demand

Ø  Plant Nutrients and Cultural Eutrophication

• Inorganic Pollutants Include Metals, Salts, and Acids

Ø  Metals

Ø  Nonmetallic Salts

Ø  Acids and Bases

• Organic Chemicals Include Pesticides and Industrial Substances
 
• Is Bottle Water Safer?

• Sediment and Heat Also Degrade Water

Hydrolic Cycle constantly redistributes Water

The hydrolic cycle is the evaporation of water from moist surfaces, falls as rain or snow, passes through living organisms, and returns to the ocean. A layer about 1.4 inches thick evaporates from the ocean every year and more than 90 percent of that moisture falls back on the ocean. The moisture that is carried onshore joins the evaporation from lakes, rivers, soil and plants to become our annual, renewable freshwater supply. Moisture distribution is influenced by water, sunlight and mountains.  Each region gets so much rain or snowfall depending on these factors. Water availability is dependent on whether there is rainfall year-round, especially in the growing season, and whether hot, dry weather evaporates available moisture.

Most Surface, Fresh Water comes from Glaciers, Ice, and Snow

Ninety percent of the 2.4 percent water that is fresh is tied up in glaciers, ice caps and snowfields. The winter snowpack on the western slope of the Rocky Mountains provides seventy five percent of the flow in the Colorado River and these and other snowfields provide fresh water supply to billions of people. 

Groundwater Stores Large Resources

Groundwater makes up the largest compartment of liquid, fresh water by originating as precipitation that percolates into layers of soil and rock. Groundwater within 1km of the surface is more than 100 times the volume of all the freshwater lakes, rivers and reservoirs combined. The zone of aeration is a relatively shallow layer of soil containing both air and water and plants get their moisture from this zone. This zone of aeration may be a few centimeters or many meters deep, depending on the rainfall amounts, soil type and surface topography. The zone of saturation is a lower soil layer where all soil pores are filled with water and this is the source of water in most wells. The top of this zone is the water table. Aquifers are geologic layers that contain water. These porous layers of the aquifers may consist of sand or gravel or of cracked or porous rock. A relatively impermeable layer of rock or clay, below an aquifer, keeps water from seeping out at the bottom. Artesian wells or springs are formed when the impermeable layers lie above an aquifer causing pressure within the water-bearing layer and make a well flow freely at the surface. The recharge zones are areas where surface water filters into an aquifer.  Contaminants can enter aquifers through the recharge zones and this is especially a problem in urban or agricultural areas. 

Wetlands, Lakes and Rivers Cycle Quickly

One of our most precious resources is fresh, flowing surface water. The amount of water that passes a fixed point in any given amount of time is how rivers are measured. This is called comparing the size of rivers in terms of discharge and is measured as liters or cubic feet of water per second. Lakes are also important in terms of water supplies and lakes contain nearly 100 times as much water as all rivers and streams combined. The lush plant growth of the wetlands also plays a vital role in the hydrologic cycle.  The plant life stabilizes soil and holds back surface runoff, allowing time for infiltration into aquifers and producing even, year-long stream flow. “Therefore, all these users must conserve and share groundwater resources to prevent its depletion and to limit the amount of water pollution” (Naseri, 2005).

One of the Smallest Compartments is the Atmosphere

The most important mechanism for redistributing water around the world is the atmosphere. An individual water molecule resides in the atmosphere for about 10 days, on average. While some water evaporates and falls within house, it can also travel around the world before it falls which replenishes the streams and aquifers on land.

Pollution includes point sources and nonpoint sources

Regulations and standards of pollution-control are usually distinguished between point and nonpoint pollution sources. Factories, power plants, sewage treatment plants, underground coal mines, and oil wells are classified as point sources because they discharge pollution from specific locations, such as drain pipes, ditches, or sewer outfalls. The ultimate in diffuse, nonpoint pollution is atmospheric deposition of contaminants carried by air currents and precipitated into watersheds or onto surface waters. There has been found to be accumulating industrial chemicals in The Great Lakes that cannot be accounted for by local sources alone. Many times, these chemicals and toxins are carried to the lakes from as far as thousands of kilometers away.

Pathogens and Waste are also apart of Biological Pollution

Pathogens are some of the most serious water pollutants in terms of human health worldwide. Waterborne diseases include typhoid, cholera, bacterial and amoebic dysentery, enteritis, polio, infection hepatitis, and schistosomiasis. At least twenty five million deaths each year are blamed on water-related diseases and nearly two-thirds of these deaths are of children 5 years or younger. It is difficult, time-consuming and costly to detect specific pathogens in water so water quality is usually described in terms of concentrations of coliform bacteria. This type of bacteria is the types of bacteria that lie in the colon or intestines of humans and other animals. If any coliform bacteria are present in water sample, infectious pathogens are assumed to be present as well and the water is deemed unsafe for drinking. A good indicator of water quality and the kinds of life it will support is by the amount of oxygen dissolved in the water. Oxygen is so important in water; dissolved oxygen levels are often measured to compare water quality in different places. Another standard measure of water contamination is biochemical oxygen demand or the amount of dissolved oxygen consumed by aquatic microorganisms. Measurement of a water source for contaminants downstream is a good way to measure from a water source. Any oxygen decline downstream is called the oxygen sag. Sediments, chemicals and the abundance of plankton organisms affect water clarity or transparency. Clarity is a useful measure of water quality and water pollution. Oligotrophic refers to river sand lakes that have clear water and low biological productivity. On the other hand waters that are rich in organisms and organic materials are called eutrophic. Human activities can accelerate eutrophication which is an effect called cultural eutrophication. Marine ecosystems can also have eutrophication, especially in near shore waters and partially enclosed bays or estuaries. Partially enclosed seas tend to be in especially critical condition. Marine animals in hypoxic zones die not only because of deplete oxygen, but also because of high concentrations of harmful organisms, including toxic algae, pathogenic fungi and parasitic protists. 

Metals, Salts and Acids are some of the Inorganic Pollutants

Chemicals of great concern in the water are heavy metals such as mercury, lead, tin, and cadmium.  Super toxic elements such as selenium and arsenic also are a hazard in some waters. Mercury, lead, cadmium, and nickel are highly toxic metals in minute concentrations. These metals can accumulate in food chains and have a cumulative effect in humans. Mercury is released from incinerators and coal-burning power plants and transported through the air into water supplies where it bio concentrates in food webs to reach dangerous levels in top predators. Top marine predators, such as shark, swordfish, Bluefin tuna, and king mackerel tend to have especially high mercury content. Soluble salts such as toxic selenium and arsenic are found in high concentrations in some soils. Sodium chloride is harmless in low concentrations but can be dangerous for plants and animals when it is concentrated by evaporation.  Acid water pollution is caused as by-products of industrial processes leach into water. Thousands of kilometers of streams in the US have been acidified by acid mine drainage so severely that they are essentially lifeless. These acids can also leach into the soil and rock, further destabilizing ecosystems.

Organic Chemicals include pesticides and Industrial substances

The chemical industry uses thousands of different natural and synthetic organic chemicals to make pesticides, plastics, pharmaceuticals, pigments and other products that we use in everyday life. Some of these chemicals are highly toxic and can persist in the environment because they are resistant to degradation and toxic to organisms that ingest them. Chemicals in water come from two principal sources: (1) improper disposal of industrial and household wastes and (2) pesticide runoff from farm fields, forests, roadsides, golf courses and private lawns. 

Is it safer to drink bottled water?

Municipal water is often safer than bottled water because most large cities test their water supplies every hour for up to 25 different chemicals and pathogens. Bottled water is often simply reprocessed municipal water or is drawn from groundwater aquifers, which may or may not be safe. Also, water that has been sitting in plastic bottles for weeks or months can leach out plasticizers and other toxic chemicals. In the long run, you are doing yourself a favor by drinking tap water.

Heat and Sediment also degrade water

Sediment is a natural part of river systems and it helps to fertilize floodplains and create fertile deltas.  However, farming and urbanization has greatly accelerated erosion and increased sediment loads in rivers and is the largest source of water pollution in the U.S. Sediment fills lakes and reservoirs, obstructs shipping channels, clogs hydroelectric turbines, and makes purification of drinking water more costly. They also smother gravel beds in which insects take refuge and fish lay their eggs.  Photosynthesis and oxygen are also in decline because sunlight is blocked out in the water. Thermal pollution also alters water temperature. The lowering or raising of water temperatures from normal levels can adversely affect water quality and aquatic life. If the temperature of tropical oceans is lowered even by one degree, it can be lethal to some corals and other reef species. Temperatures that are raised can also have devastating effects on sensitive organisms.         

Chapter 11

Chapter 11

Earth Processes Shape Our Resources

·         Earth is a Dynamic Planet

·         Tectonic Processes Reshape Continents and Cause Earthquakes

Minerals and Rocks

·         The Rock Cycle Creates and Recycles Rocks

·         Weathering and Sedimentation

 

Economic Geology and Mineralogy

·         Metals Are Essential To Our Economy

·         Nonmetal Mineral Resources Include Gravel, Clay, Glass, and Salts

·         Currently, the Earth Provides Almost All Our Fuel

Environmental Effects of Resource Extraction

·         Mining and Drilling Can Degrade Water Quality

·         Processing contaminates Air, Water, and Soil

Conserving Geologic Resources

·         Recycling Saves Energy As Well As Materials

·         New Materials Can Replace Mined Resources

Geologic Hazards

·         Earthquakes Are Frequent and Deadly Hazards

·         Volcanoes Eject Deadly Gases and Ash

·         Floods Are part of a River’s Land-Shaping Processes

Ø  Flood Control

      ·         Mass Wasting Includes Slides and Slumps

·         Erosion Destroys Fields and Undermines Buildings

The Dynamic Planet – Earth

The earth is a sphere that is layered and the core is a composed of a dense, hot mass of metal, thousands of kilometers in diameter.  This immense mass, that is solid in the center but more fluid in the outer core, generates the magnetic field that envelops the earth.  The mantle is a pliable layer of rock and it surrounds the molten outer core of the earth.  The mantle is made up of a high concentration of lighter elements such as silicon, oxygen, and magnesium.  The crust is the outermost layer of the earth and is the cool, lightweight layer. 

Earthquakes are caused by tectonic processes that reshape continents

Tectonic plates are the huge convection currents in the mantle and these are thought to break the overlying crust into huge, mosaic blocks.  Like wind-driven ice sheets on water, these plates slide slowly across the earth’s surface and, in some places, break up into smaller pieces.  Larger landmasses are also created when the plates crash into each other.  Mid-ocean ridges are formed with magma rock is forced up through the cracks of the ocean floor and this crust piles up underwater.  When an oceanic plate collides with a continental landmass, the continental plate usually rides up over the seafloor, while the oceanic plate is subducted, or pushed down into the mantle, where it melts and rises back to the surface as magma.  Volcanoes form where the magma erupts through vents and fissure in the overlying crust. 

The creation and recycling of rocks

Rocks are part of a relentless cycle of formation and destruction and they are crushed, folded, melted and recrystallized by dynamic processes related to those that shape the large-scale features of the earth’s crust.  The rock cycle is the cycle of creation, destruction and metamorphosis of the rocks.  Igneous, metamorphic, and sedimentary are the three major rock classifications.  From the Latin world for fire, igneous rocks are solidified from hot, molten magma or lava.  The earth’s crust is mostly igneous.   The melting, contorting and recrystallizing of other rocks form the metamorphic rocks.  These rocks are found deep in the ground and tectonic forces squeeze, fold, heat, and recrystallize solid rock.

These rocks are classified by their chemical composition and by the degree of recrystallization.  Jade and diamonds form under extreme pressure and heat while graphite and talc form under more moderate conditions.  There are other rocks that are formed when loose grains of other rocks are consolidated by time and pressure and these are called sedimentary rocks.  Some examples of these rocks are sandstone which is solidified from layers of sand and mudstone is from extremely hardened mud and clay. 

Sedimentation and Weathering

Weathering is a process of crystalline rocks being exposed to air, water, changing temperatures and reactive chemicals which slowly breaks the rock down.  The selective removal or alteration of specific minerals in rocks is chemical weathering and leads to weakening and disintegration of rock.  Sedimentation is when particles of rock are loosened by wind, water, ice and other weathering forces and carries the particles downhill, downwind, or downstream until they come to rest in a new location. 

Essential to our economy are metals

Economic and political power for individuals and nations has been determined by the availability of metals.  Metals are highly useful and valuable because they are relatively light, are strong and can be reshaped into many purposes.  China, Japan, Europe, and the United States are all consumers of these metals which include iron, aluminum, manganese, and chromium.  The worldwide trade market of these metals has become crucially important to the economic and social stability of the nations involved.

Gravel, Clay, Glass, and Salts are part of the nonmetal mineral resources

Soils, limestone, salts, gravel, sand and gemstones are part of the nonmetal minerals that we use.  The greatest volume and dollar value of all the nonmetal mineral resources are sand and gravel production which is used for road and building construction.  For glass we use high-purity silica and all these materials are usually retrieved from surface pit mines and quarries.  Other materials that we use in great quantity are halite, or rock salt, which is used for water softening and ice melting on winter roads and when refined, is our source of table salt.  Gypsum is used to make plaster wallboard, potash is an evaporate composed of a variety of potassium chlorides and potassium sulfates and these highly soluble potassium salts are used as a soil fertilizer. 

Almost all our fuel is currently provided by the earth

Oil, coal and natural gas are the energies on which modern society largely functions.  About twenty percent of our electricity is run by nuclear energy, which runs on uranium.  Extreme heat and pressure over many years create oil, coal and gas and they are organic, however, they are not minerals because they have no crystalline structure.  Along with providing energy, oil is the source material for plastics and natural gas is used to make agricultural fertilizers. 

Mining and drilling can degrade water quality

Underground mining, open-pit, mining and strip mining are some of the most common methods for extracting geologic materials.  An ancient method of accumulating gold, diamonds and coal is placer mining, in which pure nuggets are washed from stream sediments and another much more dangerous method is underground mining.  The method of extraction of methane gas from coal deposits that are too deep or too disperse for mining is a current controversy in the U.S.  Under both the Rocky Mountains and the Appalachian Mountains lie great deposits of coal-bearing shale but the gas doesn’t migrate easily through tight shales and so it requires many closely spaced wells to extract the methane.  The effect these wells has on the water supply is serious as each of the wells produces up to 76,000 liters of salty water per day and this toxic waste is dumped into streams which causes widespread pollution. Open pit mines are also a challenge to the water supply as water accumulates in the bottom of the pit and mixes with the metals left behind and creates a toxic soup which cannot be detoxified.  Strip mining, used to mine coal, is also a great concern as long strips of land are excavated, disturbing land and removing top soil.  Even though the soil is put back in ridges, without the topsoil and vegetation, there is great erosion of these ridges.  In recent years, there has been talk between mining companies and concerned citizens about making the mining companies socially responsible and protecting the environment. 

Processing contaminates air, water and soil

One of the most environmentally hazardous processes for extracting metals from ores is smelting.  This process heats or roasts the ores to release the metals and in the process, sulfur dioxide is released into the air.  When this was done in the mid 1800’s in Tennessee, the sulfur dioxide in the dense clouds poisoned the vegetation and acidified the soil to the point that it became a barren landscape.  Another way to extract metals is to use chemicals and one widely used method is called heap-leach extraction which involves piling crushed ore in huge heaps and spraying it with a dilute alkaline-cyanide solution.  This solution percolates through the pile and dissolves gold.  This dissolved gold is then pumped to a processing plant that removes the gold by electrolysis.  The thick clay pad and plastic liner under the ore heap is meant to keep the poisonous cyanide solution from contaminating surface or ground water, but leaks are common place. Mine operators can simply walk away once all the gold is extracted leaving behind a mess for the government to clean up.

Materials as well as energy are saved by recycling

Recycling is an efficient way to extract products that are needed such as aluminum.  Nearly two-thirds of all aluminum beverage cans in the U.S. are recycled and made into new cans.  Recycling is rapid and efficient and half of all the aluminum cans on a grocers shelf will be made into another can within two months.  Another metal that is valuable enough to be retrieved and recycled is platinum from the catalytic exhaust in used cars.  Other commonly recycled metals are gold, silver, copper, lead, iron and steel.  Another operation that is growing is mini-mills which re-melt and re-shape scrap iron and steel.  These mini-mills are cheaper to operate and perform every process from preparing raw ore to finishing iron and steel products.  These mini-mills now produce about half of all the U.S. steel. 

Mined Resources can be replaced by new materials

New materials can be used to reduce the use of mineral and metal consumption.  We see many examples of this in the use of plastic pipe which has reduced our use of copper, lead and steel pipes as well as fiber-optic technology reducing the need for copper telephone wires.  We are seeing less metals being used in vehicles as well as electronic and communication technology using glass cables instead of copper and aluminum. 

Earthquakes are frequent and deadly hazards

Sudden movements in the earth’s crust that occur along faults, or planes of weakness, and one rock mass slides past another, are called earthquakes.  The epicenter is the point on a fault at which the first movement occurs during an earthquake.  Those cities that suffer the most damage from earthquakes are for that are built on poorly consolidated alluvial soil.  This soil is water-saturated and can liquefy when sharpen and when this happens, building can sink out of sight or fall down like a row of dominoes.  Where one plate is be subducted or pushed down beneath another, earthquakes frequently occur. The tsunami is one of the most notorious effects of an earthquake.  Giant sea swells can move at 600 mph, or faster, away from the center of an earthquake.  They can create breakers as high as 200 feet when they approach the shore. “On the morning of January 26, 2001, India’s worst earthquake in half a century struck the northwestern state of Gujarat” (Administrator, 2007). The study looks at the effects of the earthquake in India on January 26, 2001.

  

Deadly gasses and ash are ejected from volcanoes

Undersea magma vents and volcanoes are the sources of most of the earth’s crust.  Weathered volcanic materials are also in many of the world’s fertile soils.  Volcanoes have been a threat to human population since the dawn of time.  Volcanoes emit denser-than-air mixtures of hot gases and ash that are deadly and the temperatures in these clouds may exceed 1100 degrees Celsius.  Volcanoes can also create disastrous mudslides that have buried towns and killed thousands. 

Floods are part of a river’s land-shaping processes

Floods are a natural and normal event that can cause damage.  Floodplains are built as the river carves and shapes the landscape and these floodplains can periodically be inundated - the larger the river, the larger the floodplain.  Floods happen irregularly and the floodplains may appear safe but eventually most floodplains do flood.  Floods take lives, cause property damage, and cause billions of dollars’ worth of damage in the worst floods.   Human activity can also increase the severity and frequency of flooding by covering the land with hardened surfaces, such as parking lots and roads, which allows less absorption of water back into the earth.  Also, building flood control structures to control the rivers just changes the water and creates a problem downstream. 

Flood Control

Flood control structures can create more of a problem when a large flood happens.  When the river is deprived of the ability spill out over the floodplains, it is pushed downstream to create fast currents and deeper floods until a levee gives out somewhere.  This creates a disaster of huge magnitude. 

Mass wasting includes slides and slumps

“Mass-wasting” is the general term used for downhill slides of earth.  Gravity is pulling down on material everywhere and it also loses material to erosion.  The sudden collapse of hillsides is called landslides and in the U.S. alone, landslides cause over one billion in property damage every year.  We see landslides a lot in California where land is expensive and people build their homes on the sides of hills thinking that they are perfectly safe, however, with soil that is exposed or if rainfall is heavy, landslides can take out whole neighborhoods.  On the other hand, soil creep moves material inexorably downhill at an imperceptibly slow pace. 

Erosion destroys fields and undermines buildings

The development of deep trenches on relatively flat ground is called gullying and is seen especially on farm fields which have a great deal of loose soil unprotected by plant roots.  Rainwater running across the surface can dig deep gullies.  Sandy shorelines and beaches see a lot of erosion because of the motion of the waves which are constantly redistributing sand and other sediments.  The beaches that run down the Atlantic coast of North America from New England to Florida are some of the most spectacular and much of this beach lies on some 350 long, thin barrier islands that stand between the mainland and the open sea.  People value the sea view so the marshes and bays along these shores have been filled in to make way for housing or recreation developments.  The construction on these beaches causes irreparable damage to the whole ecosystem. 

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