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In this unit, I will be referring mainly to true tropical rainforests unless otherwise noted. True tropical rainforests receive 160-400” of rain annually with temperatures averaging 80°F. In comparison, New York City receives an average of 43” of rain each year. Tropical rain forests contain valuable hardwoods, various food products, and vital medications, not to mention the millions of plant and animal species. More species of plant grow in the Panamanian rain forests than in all of Europe. 1,500 bird species ( 16% of all bird species ) live in the Indonesian rain forests alone. A single acre of tropical rain forest supports 60-80 tree species compared to the United State’s richest temperate forests at 25 species per acre.
Inter-American Bank and World Bank have promoted rainforest ranching by loaning almost $4 billion to ranchers in the 1970s. To meet the demand for mahogany, teak meranti, and ebony, at least eleven million acres are logged each year. Since these hardwoods take hundreds of years to mature, they cannot be readily replaced. Although only the oldest and largest trees are supposed to be felled, more than half of the forest may be damaged by the time all of the work is finished. Tropical hardwoods are especially valuable because of their beauty, durability, and resistance to insect damage. Industrial countries buy over eighteen times more hardwood today than they did fifty years ago. A lack of local political control has allowed overcutting in many forests. Studies show that logging can result in the loss of valuable economic revenues in the areas of tourism, food products, and fisheries. Increased sedimentation of many rivers threatens fish populations downstream. Alternatives to typical clear-cutting practices, such as selective logging and small-patch clear-cutting can lead to sustainable timber harvesting. Unfortunately, neither practice is widely used. According to the International Tropical Timber Organization (ITTO), such efforts have had “negligible” success. Continuing at the current pace, high profits from commercial logging will be short-lived. Presently, the tropical timber trade produces $6 billion per year. However, by the year 2000, that figure will drop to only $2 billion because of shrinking supplies and poor logging management. In many countries, slash-and-burn agriculture is a leading cause of tropical deforestation. Slash-and-burn agriculture is a farming method in which patches of tropical rainforest are cut and then burned to clear the land for crops. For the first few years, crops do quite well due to the nutrients in the soil and ashes. But eventually, the soil wears out and the plot is usually abandoned. On a small scale, slash-and-burn agriculture is sustainable but only if the land is given time to regenerate itself. Unfortunately, this is often not the case and the land does not recover. It is imperative that the rainforests be saved because the trees and plants help to keep the air around us clean. They use water, sunlight, and air to make food. Plants and trees make use of carbon dioxide and produce oxygen, which helps everyone breathe. When the rainforests are burnt down or destroyed, the trees stop using carbon dioxide and instead, produce more CO2 which pollutes our atmosphere.
- bromeliads—tropical plants in the pineapple family that often grow on the trunks and branches of trees.
- buttresses—woody flanges that radiate from the bases of tall tropical trees which help support shallow-rooted trees.
- deforestation—the destruction of a forest.
- epiphyte—a plant that grows on other plants.
- ethnobotany—the study of how people use plants.
- extinction—when the last member of an animal or plant species dies out.
- indigenous—referring to tribal peoples, such as American Indians, who lived in an area before Europeans arrived.
- shaman—a tribal priest/doctor who has great knowledge of the medicinal qualities of native plants.
- sustainable development—development that uses natural resources in an efficient way and without destroying the basis of their productivity.
- tropical rainforest—an evergreen forest located at low elevations in regions between the Tropics of Cancer and Capricorn. It is characterized by abundant rainfall and a warm, humid climate year-round.
Immediately following a spill, low-boiling hydrocarbons such as benzene and toluene cause the sudden death of shellfish and many fish in their larval forms. Other chemicals remain on the surface that adhere to sea otters, birds, rocks, and other objects. This “coat” of oil destroys the animals’ natural insulation and buoyancy. Most ultimately die from loss of body heat or drown. Heavy oil components that sink to the ocean floor have the most devastating effects on marine life. They kill crabs, oysters, clams, mussels, and completely alter all food chains. Generally, marine life can recuperate within three years of such accidents, but cold, polar waters take longer for recovery. It is generally accepted that the heavier the oil, the less toxic it is. While scientists theorize that oceans are strong and resilient, the toxification of the water is closely connected to other pollutants that threaten Earth’s biodiversity. As John Cairns, a marine ecologist, states, “should an entire ocean be damaged, the time required for recovery staggers the imagination.” Oil spills have been with us for quite a while in our history. Reports of oil damage date back to the Civil War. Back in 1912, the New York Zoological Society reported that it could not use local harbor water for its aquarium tanks because oil contamination was killing specimens.
Since 1973, the actual number of accidents per year has decreased due to better training, and improved safety measures. However, this relaxed attitude toward standards by oil companies led to disasters such as the Exxon Valdez. Some 10,000 spills occurred in the year alone following the Exxon accident. At least three of those were in the million-gallon range. Since these smaller spills occur all of the time, the constant toxic pressure on coastal ecosystems is tremendous when accompanied by the occasional huge spill. Estimates are that anywhere from 1-10 million tons of oil are spilled each year into our oceans.
The fate of spilled oil depends on the nature of the crude. Number 6 heavy crude barely floats and is extremely viscous. Number 4, which is light crude, and Number 2 heating oil are lighter and less viscous, therefore spreading more easily across the oceans surface. These lighter oils contain more aromatic hydrocarbons and lower boiling alkanes. The low boilers induce anesthesia and narcosis among fish and invertebrates.(Taken from The Environment by Gerald Leinwand)
In the early 1970s, conservationists predicted there would be a large spill so they urged politicians to transport oil via a pipeline to reduce potential damage. The oil companies won by a 50-49 vote in the United States Senate. Since 70% of the worlds oil output travels by sea, it is quite apparent why the conservationists were concerned about the oceans future.
The 1989 spill, which covered some 4,000 miles of shoreline, killed hundreds of thousands of marine birds and thousands of sea otters and fish. Large, but indeterminable amounts of seals, sea lions, porpoises, dolphins, and whales are presumed dead as well. Human clean-up crews were also exposed to health risks by the toxic chemicals. Tar is fed upon by marine turtles and, accompanied by plastic garbage in the water, is a major cause of their decreasing numbers. Finally, bald eagles and other birds may also be affected indirectly through the toxins built throughout the food chain. The final toll, however, will never be known because many of the animals sank.
The area of the spill is known as Alaskas Emerald Jewel -Prince William Sound. The eleven million gallons of thick, toxic crude oil cost nearly $2 billion to clean up, making it one of the costliest spills ever. What is especially sad is that this major tragedy could have been avoided, or at the very least, controlled. Most of the clean-up measures were not effective. In hindsight, it would have cost Exxon only $22.4 million to have a second, protective hull built. The ultimate irony is that the captain of the Exxon Valdez was drunk on duty according to blood tests. His automobile drivers license was revoked due to his alcohol problems yet Exxon still let him take charge of a super tanker more than three football fields in length.
While Exxons corporate greed was a major factor in the tragedy, we as consumers must also share some of the blame. Our careless and wasteful habits have created such large demands for domestic oil. Ironically, oil carelessly dumped by consumers (from automobile, lawn, and recreational equipment) is equal in volume to twenty or more spills by the Exxon Valdez on an annual basis. The argument has been made that the Exxon Valdez was an accident, whereas our own oil spills are done with reckless intent.
During the Exxon Valdez spill, a method was attempted that actually turned out to be more destructive in the long run. The clean-up crews tried to wash the oil from the beach by using powerful streams of hot water. The ultimate effect was that this cooked marine organisms in 65øc water. Since oil spills will continue to occur, as seen recently in the Shetland Islands, solutions to this problem will come from future generations.
It is important to mention that oil spills are not the only threat to our oceans. Sewage, industrial waste, insecticides, herbicides, natural runoff, and constant polluting all account for the problems. In 1988, everyone can remember beaches along the eastern U.S. closing due to contamination from medical wastes. Every individual can do his/her part to keep our oceans clean. By conserving oil, recycling, being informed consumers, writing letters to politicians, and car pooling, we can all improve the quality of our oceans. After all, were not called the Blue Planet for nothing!
As David Bulloch aptly states in his book, The Wasted Ocean, We simply do not comprehend the extent to which we have stretched the resiliency of nature, nor do we recognize that nature, bent under these new and strange stresses, is losing its elasticity. Experience has yet to teach us that neither the private ownership of land nor the use of common water conveys the right to spoil them. Land, water, and wildlife are not artifacts along the course of civilization. They are its roots.
Our scientists have concluded the second leg of their journey. They will gather all of their data from Valdez, Alaska, and have a final report upon their return to Connecticut. Our scientific group will also present methods to stop the contamination of our oceans and various techniques to effectively clean-up oil spills.
During their research, Molina concluded that each chlorine atom from CFCs collides with an ozone molecule. While ordinary oxygen molecules have two atoms, ozone is made of three oxygen atoms and is very unstable. Ozone will tend to give up one of its oxygen atoms to other gases and turn back into oxygen. In brief, the breakdown of CFCs by sunlight would set off a catalytic chain reaction in which one chlorine atom could eat up 100,000 molecules of ozone, turning them into impotent oxygen molecules.
Derived from the Greek work ozein which means to smell, ozone at the ground level gives off an acrid odor. The ozone layer is really only an eighth of an inch thick. For every 1% decrease in the ozone layer, cases of nonmelanoma skin cancer are expected to increase 5-6%. Since some CFCs take one hundred years to decompose in the atmosphere, we will live with the consequences of CFCs for another 100-150 years at least. As Vice-President Al Gore stated, While we have hardly begun to make the dramatic changes that will be necessary, it is a revolutionary step for society to recognize the problem at all.
Reactions to Molina and Rowlands 1974 discovery was minimal at best. Du Pont, the worlds largest CFC manufacturer, discredited their findings and refused to initially acknowledge the ozone problem as a serious threat to the environment.
The history of the chlorofluorocarbon is an interesting one indeed. CFCs were discovered in 1928 by Du Pont chemist Thomas Midgley,Jr. A colleague had told Midgley that the refrigeration industry needed to improve. At that time, ammonia or sulfur dioxide was used but they were not very effective. The new refrigerant must be nonflammable, nontoxic, and stable. After much experimentation, Midgley created the compound fluorocarbon. Freon was the trademark name that Du Pont gave to its new class of fluorocarbon chemicals. Freons F-11 and F-12 were the most widely used in the 1930s and now it turns out that they are the most dangerous to the ozone. Other health threats associated with the use of aerosols and CFCs include the risk of cardiac arrest when CFCs are in high concentrations. In smaller doses, they could cause changes in normal heart rhythms. Although the nations policymakers were aware of the CFC threats, it would take them the next fifteen years before any serious action would occur. American consumers did not waffle on the issue, however. The CFC-ozone theory generated more letters to politicians than any issue since Vietnam. About half of the people surveyed said they had already stopped using aerosol products. In 1984, Rowland expressed frustration and disgust that ten years after their revelation, nothing was still being done about the problem.
Unfortunately, this means that if there is a disaster in the making in the stratosphere, we are probably not going to avoid it, Rowland warned. Sadly, Rowland would be proven correct just months later when the British Antarctic Survey released data showing that the ozone hole was increasing over the South Pole. Scientist Joe Farman and his research assistants had been studying at Halley Bay, Antarctica, since 1957. Since they had spent twenty-five years there, the results of their findings had credibility. Having used the old ground-based Dobson spectrophotometers to read ultraviolet light that reached earth, however, Farman doubted his own results at first and requested brand new equipment. Nevertheless, the new equipment confirmed the previous data. The ozone had actually begun to decrease back in 1977. The Nimbus 7 satellite took ozone readings from 600 miles above the earths surface. The Antarctic ozone hole suddenly appeared before our eyes
One possible explanation for the 1983 ozone decrease was the volcanic eruption of El Chichon in Mexico in April 1982. Rowland theorized that the massive amounts of sulfuric acid spewn into the atmosphere could react with chlorine nitrate and cause ozone loss. Rowland and other researchers debated over this theory. After experimenting with chlorine nitrate, hydrogen chloride, and water, the group concluded that the volcano could have created some ozone depletion.
However, vehement arguments as to what was causing the ozone hole arose from the entire scientific community. A popular theory called the dynamicists theory suggested that air movement was the cause of the hole. A third theory, called the odd nitrogen theory, suggested that the solar cycle was the cause of abnormal ozone fluctuation.
In a 1985 report by NASA, statistics showed that if CFC emissions continued at 1980 rates, the ozone would decrease 4.9 to 9.4% by the next century. Even if the Antarctic hole was linked to CFCs, regulations of non aerosol uses would be difficult to control. In the 1970s, consumers had a vote and they chose to protest aerosol products. Now,however, it is harder to walk into an automobile dealership and request a car with an air conditioner free of fluorocarbon-12.
In June 1986, a series of hearings and meetings were scheduled in Washington. Both sides of the issue brought out their toughest tactics. Environmentalists and scientists testified that the greenhouse effect was a cause for concern. According to the EPA, changes in climate could cause the extinction of some species. Crops in semiarid regions would die. The number of 100øf + days would increase from 3 to 20 in Omaha, Nebraska, for example. Sea-level increases of 2-12 feet by the year 2100 could easily flood coastal cities such as New Orleans. Protecting wetlands, beaches, and even drinking water would be impossible. Just protecting our countrys east coast could cost an estimated $10-100 billion. Traces of CFC contributed to the greenhouse effect at rates comparable to carbon dioxide.
Other shocking reports stated that ultraviolet radiation could reduce seed quality, lower a species resistance to pests and diseases, damage aquatic systems, and destroy fisheries. A 25% loss in ozone would result in a 35% loss of phytoplankton, the main food source for many marine animals..
Surprisingly, the instruments were performing well enough to gather solid data. In Antarctica, its a challenge to do anything. Temperatures often reach -90 F By the end of the expedition, they had gathered strong evidence to prove that chemicals were causing the rapid ozone depletion. Solomon discovered high levels of chlorine dioxide which implicated CFCs. Satellite data showed that ozone was being depleted in a huge region to at least 45 south latitude (the Southern tips of South America and Australia).
A larger and more detailed expedition was needed in 1987 to accurately solidify the chemical theory. The $10 million project would hopefully resolve many of the uncertainties from NOZE I.
On September 1 6,1986, the Alliance for Responsible CFC Policy held a press conference announcing that it would encourage the limit on the growth of CFCs. Replacing CFCs in refrigerators, air conditioners, and solvents would be much more difficult than the substitutes of aerosol sprays. The three main chemicals that needed to be replaced were: CFC-11 (used in making polyurethane foam); CFC-12 (used in refrigeration,air conditioning, and foam blowing); and CFC-113 (used as a solvent in the electronics industry). On September 14,1987, the Montreal Protocol was signed by 43 nations. The 43 countries agreed to a freeze on consumption and production of CFCs at 1986 levels by 1990; a 20% reduction by January 1,1994, and an additionalcut of 30% by January 1,1999. The Protocol stated that all nations would meet again to eventually eliminate ozone-destroying chemicals.
To familiarize students with the three geographical locations of their journey: Brazil, Alaska, and the South Pole. To create an understanding of mileage, costs, time zones, and governmental restrictions while traveling to these destinations.
Atlases, travel guides, passports,travelers checks, a scientific journal for logging information.
Each scientific group will obtain their passports (by making them) and create a list of items they will need for their three month long trip. Next, they will use maps and atlases to research mileage to each destination. By contacting travel agencies, they will learn approximate costs of each plane flight. They will next budget how much money they will need to bring and then buy enough travelers checks. After obtaining all of their necessary documents and items, the group is ready to depart for the first stop of their expedition: Brazilian rainforest in South America!
To classify various rainforest animals into their appropriate invertebrate and vertebrate groups. To understand the characteristics and features of each group and distinguish amongst them.
Various pictures of rainforest animals from old magazines or photocopies.
Rested after the long flight, our scientists waste no time in exploring the rainforest. They have spent several days and nights examining and observing the many species of animals located throughout the forests layers. After taking hundreds of pictures and countless notes, they are all gathered back at their lab to study the pictures and research their data. For example, our scientists will put all vertebrates into their appropriate category: fish, reptile, amphibian, bird, or mammal. They will then analyze various survival techniques, unique adaptations, unusual body appendages, and symbiotic relationships in the rainforest. The majority of their work will be with the invertebrates, though. With millions of species of insects alone, our scientists will be very busy classifying these animals.
To experiment with various clean-up techniques of an oil spill. To analyze which methods are the most effective and which are the least productive.
a baking pan, cooking oil, baking soda, dish washing liquid, paper towels, a sponge, cold water.
Our scientists have explored the Prince William Sound area and have now returned to their research lab with various oil specimens. They will attempt to clean the oil from a small confined area so that they might eventually try these techniques on the open waters. First, they will add enough water to a pan to fill it halfway. Then they will add the oil that they collected. Next they will begin their various clean-up techniques such as baking soda, dish washing liquid, skimming the surface with paper towels and soaking the oil with a sponge. The group will record their findings and determine which method was the most effective. Some questions they might ask themselves are: Did any method leave an additional residue on the water?, Did any of these methods create additional harm to marine life?, or Which method would best be attempted on larger areas?
To experiment with various weather watching instruments. To analyze how weather affects how lives and what it is capable of doing to our planet.
thermometer, anemometer, rain gauge, barometer, almanac, atlas, and chart for recording data.
Our scientists are preparing for their trip to Antarctica. While there, they will study the weather intensely, analyzing what affects weather might have on the ozone problem. Prior to their departure, the group will test their meteorological instruments to verify that everything is working properly. For two weeks, our group will check the air temperature, wind speed, wind direction, air pressure, precipitation amounts, and general weather conditions each day. Keeping all of their data on charts, the group will determine the mean temperatures and other averages using their math skills. Knowing that their equipment works properly, our scientists will now use almanacs and other resources to determine average temperatures in Antarctica for the time of the year that they are traveling there. As a final step in this lesson, the scientists will compare and contrast weather conditions in Antarctica with those here in Connecticut. Our group will hypothesize on what effects the weather might have on the depleting ozone layer and possible solutions to this environmental problem. Several groups may want to share their findings with each other to see any similarities or differences.
The Environment by Gerald Leinwand (Facts on File, 1990).
Life in the Rainforests by Lucy Baker (Scholastic, 1990).
Living in the Environment by G.Tyler Miller,Jr. (Wadsworth Publishing, 1990).
Nature’s Revenge by Scott Sullivan (Newsweek, March 2,1987).
Oil Spills and the Marine Environment by Donald F. Boesch (Ballinger Publishing, 1974).
Ozone Crisis by Sharon L. Roan (John Wiley and Sons, 1989).
The Ozone War by Lydia Dotto and Harold Schiff(Doubleday & Co., 1978).
The Rainforest Book by Scott Lewis (Living Planet Press, 1990).
Ranger Rick’s Nature Scope: Rainforests by the National Wildlife Federation (1989).
Save Our Planet by Diane MacEachern (A Dell TradePaperback, 1990). Sea Otter Rescue by Roland Smith (HBJ, 1993).
The Wasted Ocean by David Bulloch (Lyons and Burford Publishers, 1989). Our Mission: Save Planet Earth.
Contents of 1993 Volume V | Directory of Volumes | Index | Yale-New Haven Teachers Institute