Case Study Videos

National Geographic Video Case Studies
Wright, Environmental Science, 9^th Edition

 These videos are available to textbook adopters by contacting their Prentice Hall representative.

Riding the Commuter Rail to Bombay (2m. 53s.)

What is it like to live in a populous developing world city? In this segment about the Indian railway system, the "8:54 group" of commuters to Bombay shows how they get a place on the platform so that when the train arrives, some of the group is positioned to leap on board before the train stops to save places for the other members. Bombay, with a population of 13 million and a density six times that of New York City, is the financial capital of India. Five million people pour into and out of the city daily, mostly on the commuter trains that arrive in the city every two minutes. Trains designed to hold 1700 passengers are packed with up to 7000, producing "hyperdense" crush loads. Bombay is one of many developing world megacities whose infrastructures are overwhelmed by the needs of their expanding populations. In Kerala, the southernmost state of India, fertility has dropped to below replacement level, but this is not the norm. Most of India is still stuck in the middle of the demographic transition, and scenes like the Bombay commuter rail are indicative of the challenge ahead. Wright reference: Chapter 5, pp. 132, 146-147; Chapter 6, pp. 151-152.

Colorado River Water Wars (4m. 10s.)

The only significant surface water source in the southwestern United States is the Colorado River. Seven states and Mexico vie for its water, with the result that the river disappears into the sand before reaching the Gulf of California. The video depicts the plight of Las Vegas, which uses its entire allocation of Colorado water and is faced with supplying water to the thousands moving to the city each year. The major competition is California, whose desert landscapes are fed with Colorado River water to support its rich Imperial Valley farms and other irrigated croplands. Both the Hoover Dam and the Glen Canyon Dam have harnessed much of the river's flow and changed the ecology of the river, but the bottom line is the rainfall that feeds the Colorado River basin, and that is placing limits on all uses of the river's waters. How the southwest will settle the "water wars" caused by the growing demands on water for irrigation and domestic needs is anybody's guess. Wright reference: Chapter 7, pp. 180, 192-193, 199-201.

The Potomac River: Water for a Sprawling Megalopolis (4m. 52s.)

Another "water war" is brewing in the heavily populated eastern United States. The Potomac River supplies water for more than 3 million residents of the DC area. As the suburbs continue to sprawl out into the countryside of Maryland and Virginia, the demand for clean water is challenging water authorities in both states, especially during times of drought. A curious historical arrangement is described in this video segment, where Maryland claims to "own" the river because of a King's grant in 1632. Virginia has challenged this claim, especially since 40% of the Potomac's flow originates in the state. The video highlights the fact that clean, safe drinking water is a key resource that can not be taken for granted. Wright reference: Chapter 7, 189-191, 200-202; Chapter 23, 637-645.

Mapping the Rice Genome: Biotechnology's Promise (3m.)

The techniques of genetic engineering have made it possible to read the entire genome of a species; this has now been done for humans, mice, many bacteria and viruses, and as shown in this segment, rice. The film points out that more than half the world's people eat rice daily, and countless millions toil daily to cultivate this essential food crop. Two teams have completed a "draft genome," to be filled out in more detail with time. Although not mentioned, one of the teams is from China's Beijing Genomics Center, a healthy sign that biotechnology is spreading to the developing world, where food needs are the greatest. The program points out the hope that the genome's mapping should make further work to enhance the nutritional quality and agricultural potential of rice quite feasible. It is hoped that as a result, the food security of many hungry people will be enhanced. Wright reference: Chapter 9, 233-234, 243-247.

The Florida Panther: Endangered Species on a Comeback (4m. 7s.)

Once found across the southern United States, the Florida panther is now confined to a small corner of the Everglades of south Florida, where some 70 to 100 animals represent the last of this race of the cougar. This film shows the steps being taken to bring this population back from its low of 30 animals in 1984. One unusual step was to introduce 8 female cougars from Texas in order to revitalize the gene pool of the Florida race. This seems to have worked well, and the Texas panthers have been removed, leaving offspring with genes from both cougar populations. Many of the panthers are wearing radio collars, providing vital information to wildlife managers on the habitat and range of the animals (single animals need some 50 to 200 square miles). Mortality studies indicate deaths from other panthers and alligators, but the greatest threat to the animals is the urban sprawl that characterizes south Florida and the breakup of the habitat that leads to dangerous contacts with traffic and suburban environments. For more, see http://www.panther.state.fl.us/.  Wright reference: Chapter 10, p. 269-274; Chapter 11, p. 297-299.

Restoring the Cod to Newfoundland's Waters. (4m. 10s.)

In a somewhat irreverent play on an American theme, Newfoundlanders have highlighted the economic backbone of their province with the saying "In Cod We Trust!" The Grand Banks off Newfoundland and Nova Scotia were once the richest fishing grounds in the North Atlantic, but overfishing brought the cod to "commercial extinction," forcing the Canadian government to declare a moratorium on cod fishing in 1992 across many of the traditional fishing grounds. Once skeptical of the fisheries scientists for their dire forecasts, the fishing community is now working together with the scientists in an effort to collect vital information on the fish and build up a vital data base. The sad news is that a total moratorium was declared in 2003 on all cod fishing off Newfoundland, the Maritimes and Quebec, because the cod were not rebounding as expected. This is an all too common story across the northern waters that once held abundant populations of cod, haddock, flounder and other important food species, and it points to the crucial need for tight management of ocean fisheries based on sound science – a difficult task. Wright reference: Chapter 11, pp. 304-308.

Aquaculture's Next Wave. (5m. 4s.)

With the collapse of many of the commercial fisheries around the world, the best prospect for meeting the rising demand for fish and shellfish is aquaculture. Currently, aquaculture is expanding at a rapid rate, but not without some problems. Marine aquaculture employs net-based pens and cages suspended in coastal embayments, but these produce wastes and sometimes allow the fish to escape and mix with the wild stock, a potentially disastrous situation. One solution to these problems with current aquaculture is shown in this video segment, which documents the work of Dr. Yonathan Zohar in a facility in Baltimore's inner harbor. The Center of Marine Biotechnology (COMB), directed by Zohar, is experimenting with a completely enclosed aquaculture system for raising fish. Starting with artificial seawater, the fish are raised in circulating tanks, with computer controlled environmental conditions and a key process of biofiltration to process wastes. According to Zohar, this may be the "next wave" of aquaculture technology. For more information on COMB, see http://www.umbi.umd.edu/~comb/index.html.  Wright reference: Chapter 11, pp. 305-306.

Wind Turbines: Snatching Power out of Thin Air. (2 m. 47s.)

The winds that blow across Texas, Kansas and North Dakota are sufficient to power the whole country, according to this report on wind power. Wind turbines are being built all over the world, as wind energy becomes more and more competitive with fossil fuel-based energy. Concerns about greenhouse gases and trouble in the Middle East has spurred moves in many countries towards energy independence. Wind power represents a technology that is readily available and can be quickly installed, and it is spreading throughout Europe and even reaching to India. In the U.S., the Bonneville Power Administration is planning to double the number of wind turbines serving the Pacific northwest, a region that is pushing wind energy in many locations. Although this report doesn't mention the problems with wind power (aesthetic, bird kills), it does show how this energy source is moving ahead with "snatching power out of thin air!" Wright reference: Chapter 14, pp. 374-376, 388-389.

Fuel Cells: Complement to Solar and Wind Power. (4m. 12s.)

Renewable energy from wind turbines and solar PV cells is the key to the 21^st century energy future. One problem, however, is that these sources are not constant. This report suggests that the key is to combine these abundant but intermittent energy sources with fuel cell technology. The video highlights work at Humboldt State University's Telonicher Marine Laboratory in Trinidad, California, where renewable energy combines solar PV cells and fuel cells to power up a research aquarium system. Here hydrogen gas generated by solar panels is stored in tanks and made available for fuel cells whenever solar power is down. Fuel cell technology is explained and compared with the way transistor technology spread through society; the message is that fuel cells will one day be just as revolutionary. The goal of an independent, totally reliable power source is achievable, according to this report, but the technologies still face stiff competition from the conventional fossil fuel-based electrical grid. For more information see http://www.humboldt.edu/~serc/trinidad.html. Wright reference: Chapter 14, pp. 391-394.

Lyme Disease: Fastest Spreading Emerging Disease in the United States. (4m. 8s.)

A cluster of arthritis-like symptoms in children in the town of Old Lyme, Connecticut, in the mid-1970s, led to the discovery of what is now called Lyme disease. An intensive investigation revealed the disease as a result of the bite of a deer tick (Ixodes scapularis) that was carrying a spirochaete bacterium, Borrelia burgdorferi. Mice and deer are key elements of the tick's life cycle. If left untreated, the disease can lead to severe arthritic joint problems and, in some, nervous system disorders. This report follows the tick life cycle, showing how it can attack humans and in many cases, lead to Lyme disease. The classic symptoms of a bulls-eye rash are shown on a patient, who is assured of complete recovery because of early diagnosis. The ticks are becoming common throughout the Eastern, Midwestern, and Pacific coastal United States, carrying with them the bacteria that cause the disease. For a fuller look at Lyme disease and how to avoid it, see http://www.cdc.gov/ncidod/dvbid/lyme/. Wright reference: Chapter 15, pp. 407-408, 422.

Water Rising in Holland. (4m. 25s.)

Many are familiar with the story of the Dutch boy who saw a leak in the dike that held back the sea, put his hand in the gap until help arrived, and saved his town. Those dikes are still present, still protecting the Netherlands from the sea. More than 10 million Dutch live below sea level, protected by the constant work of pumps, barriers and dikes. A new threat now looms, as global climate change brings with it a steadily rising sea level. The changes are expected to bring dryer summers and more intensive winter storms that even today constantly challenge the coastal barrier system. Some ideas presented in this report are radical: instead of struggling, give some of the country back to the sea, where the lowest-lying lands closer to the sea could act as flood control lakes. Another suggestion is to build floating houses, in some ways an attractive option (because people enjoy living near the water) that is already being explored. The Dutch predicament is symptomatic of the challenge of global climate change to all low-lying regions, many of which are found in the Pacific island nations and other developing nations. Somehow, adaptation to the relentless rise in sea level will be necessary, unless the world moves effectively to bring a halt to the rise in anthropogenic greenhouse gases. Wright reference: Chapter 20, pp. 546-564.