Now We’re Cooking

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From Afghanistan to Zimbabwe, people around the world are turning to the sun as a viable source of energy. Most practical in climates near the equator, solar ovens offer an alternative for those who depend daily on firewood and charcoal to cook their food. The devices, ranging from simple to complex, are meant to slow deforestation and the slew of problems that come with it—such as biodiversity loss, global warming, desertification, landslides, and floods. In addition, solar ovens offer a safe alternative for women who may walk for miles in search of wood in depleted forests or refugee camps and a healthier alternative for families who inhale smoke from wood-burning ovens. Currently, indoor air pollution kills almost 2 million women and children around the world each year.

On the island of Madagascar, deforestation has been widespread. Where lush, green forests once sustained a diversity of endemic species, today the land is used to graze cattle or lays barren. Ninety percent of Madagascar’s original forests have been lost, mostly to use as firewood. When the human population grew from four to 20 million after 1960, the demand for firewood climbed beyond sustainable levels.

A Swiss organization called ADES (Association for the Development of Solar Energy) introduced solar cookers to Madagascar. Since 2001, ADES has produced and sold solar cookers on the island to help ease the burden on the environment. With around 300 sunny days per year, conditions in Madagascar are perfect for solar cooking. However, the acceptance of any new technology can take time. Some challenges that the organization is currently facing are described below.

  • Madagascar is one of the poorest countries in the world. Even though the basic box cooker is sold at less than it costs to produce it, it is still too expensive for most.
  • People are comfortable with and used to cooking with firewood and charcoal.
  • Food that is not cooked over flames doesn’t taste the same, and the cooker can’t be used to prepare ranovola, a burnt rice tea that is served with most meals.
  • Cooking with the box solar cooker, which generates temperatures up to 150°C, takes much longer than cooking with traditional ovens


1. Work with a small group to brainstorm solutions to each of the problems listed above

2. Using the following links or others, research solar cooker designs:

Select an alternative solar cooker design to introduce to the people of Madagascar, or describe your own design, using elements of existing plans. Explain your choice.

3. Draw a concept map showing how technology advancement, economy, environment, and social issues are related in this case study.

More to Explore
Solar Cookers International
Solar Cooker’s World Network Madagascar Site
ADES Website
Solar Cooker Newsletter

Stocking Lakes with Fish

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Fishing is a popular pastime, and the practice of stocking lakes with fish to catch is popular, too. Organizations that manage natural resources add fish to lakes and streams to make fishing more fun for anglers. It can provide sport fishers with fish that are big enough to keep, and sometimes fish that are big enough to be considered trophy-sized.  Rainbow trout (Oncorhyncus mykiss), walleye (Stizostedion vitreum), Atlantic salmon (Salmo salar), northern pike (Exox lucius), blue gill (Lepomis macrochirus), and muskellunge (Esox masquinongy), commonly called muskie, are some species of fish that are raised in hatcheries and released for sport fishing. Many species that are used for stocking have low reproductive rates and slow growth rates. They are easily overfished if their populations are not supplemented through stocking.  Stocking lakes and streams can create new recreational fishing opportunities, support existing native populations of fish, and restore threatened or endangered populations. Lakes are often stocked right before the fishing season opens, or when a park is holding a regional celebration. If people have a good chance to catch a big, desirable fish, they are more likely to buy a fishing license. More fishing licenses sold means more revenue to use to protect and maintain natural resources.

Despite the benefits of fish stocking, not everyone feels that stocking lakes and streams with fish is a good idea. One large waterway conservation group, the Pacific Rivers Council (PRC), believes that using fish stocking as a management technique diverts money and other resources that could be better used in other conservation and protection efforts. The PRC has also found that a decline of native golden trout in California is linked to fish stocking. In total, 35 species of fish and amphibians have been affected by stocking practices in California alone.  Genetic hybridization between introduced and natural fish species can occur, which lowers the fitness of the natural populations. Adding fish to a lake or stream can also introduce disease, to which hybrid fish are more susceptible. A scientific study of Virginia streams found that the infectious pancreatic necrosis virus was found only in brook trout populations that had a history of fish stocking. In Wisconsin, seven species of fishes were found to have lymphocytis due to the stocking of walleye.

Fish stocking can also change the balance of an ecosystem. Fish that are stocked are often apex predators. Native fish species may become prey of the introduced fish, and existing populations will also have to compete for food and habitat. Many fish species prefer to have cover, such as undercut banks, abundant vegetation, or large rocks to hide beneath, but cover is limited in many aquatic ecosystems. Stocked rainbow trout have outcompeted many of the native brook trout populations in the southeastern United States. Even bird populations that feed on fish can be affected. Cormorants and other predator bird species prey heavily on trout when they are first stocked in Washington lakes. Trout that have been raised in hatcheries tend to stay near the surface of the water for the first few weeks until they start cuing into the natural food sources closer to the bottom of the lakes. How the sudden, short-term abundance of food for these bird populations affects the entire food web is unknown.

Despite all of these concerns, fish stocking happens regularly and often multiple times in a lake or stream during one season. In Virginia, researchers have found that despite regular stocking of rainbow trout, 80 percent of fish in streams are still native brook trout.  Minnesota’s Department of Natural Resources (DNR) determined that stocked muskie will coexist with natural fish species because the DNR uses biologically-based guidelines in choosing which lakes to stock and do not stock high densities of the predator fish. Some Minnesota residents, however, feel that the increased boat traffic that fish stocking causes also increases the risk of introducing invasive species such as Eurasian milfoil, an aquatic plant that is difficult to control. Throughout history of humankind, there have been many examples of introduced species that have caused havoc on ecosystems. Is fish stocking a similar story, or a sound management technique? 


1. What are the benefits of fish stocking?

2. What are the disadvantages of fish stocking?

3. In your opinion, is fish stocking ever a good idea, or should it be completely banned? Explain your answer.

More to Explore
Texas Parks and Wildlife Department Winter Trout Stocking Program Angling Tips
Endangered Fishes Hatchery

Drinking Bottled Water

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Does your family buy a case of bottled water when they go to the grocery store? Do you buy a bottle of water from a vending machine or convenience store when you are away from home? The good news is that we are making healthier beverage choices and drinking more water than ever before. Large soda corporations have bought up bottled water companies because water is the biggest area of growth in the beverage industry worldwide. The bad news is that many of the plastic bottles that contained water are ending up in landfills. These plastic bottles can take many centuries to biodegrade. Do we need to change our habits, or are environmental groups making water bottles an undeserved villain? Consider these points of view from an environmental group and a bottled water company:

Environmental Group spokesperson: Plastic bottles are recyclable. They are commonly reused to make new bottles or containers, carpet, fleece clothing, and construction material for decks and playgrounds. But many more water bottles are thrown away than are recycled. Only about one out of every six bottles makes it to a recycling plant. Think of your habits and the habits of your family and friends. Even if we recycle at home, we often throw our water bottles away in the trash if recycling is not readily available at the park, school, or other public place.

It is not just the landfills that are impacted by water bottles. Plastic bottles are lightweight and often end up along our roadsides, in streams and lakes, and ultimately as marine debris in our oceans. Plastics are made with petroleum and it takes a lot of energy to make, fill, cap, and ship the bottles around the world. One study found that filling a water bottle one-quarter of the way full with oil demonstrates how much fuel it takes to bring that bottle of water to a consumer. Petroleum is a limited, nonrenewable resource and producing water bottles is an unnecessary use of energy by big companies just out to make money. Drilling for oil and the inevitable spills and leaks of that industry also harm the environment. When oil is used to produce energy, it contributes to air pollution, greenhouse gas production, and global climate change.

Bottled water is also a big rip-off for consumers. Although almost every place in the United States has safe municipal tap water to drink for about 0.00002 cents per ounce, we pay 1000-4000 times more for water that is shipped from far-flung places such as small tropical islands or European countries like France. These places may rank high in tourism but that does not mean they have superior water. Some of it is even from municipal water supplies in our own backyards. Even though some people might have the perception that bottled water tastes better than tap, scientific studies have shown otherwise. At a blind taste test at one college campus, tap water was chosen over bottled water by the majority of people four out of five times.

Bottled water is not even the healthiest choice in most cases. Tap water has higher standards of quality than bottled water. For instance, bottled water is not held to the same fecal matter standards that tap water is. Bottled water that has been stored on shelves for a few weeks can leach chemicals from the plastic into the water, including endocrine-disrupting phthalates that have been linked to cancers and infertility. People need to carry water with them in reusable bottles and stop buying water in plastic bottles. There should also be a national bottle deposit law so that people have an incentive to recycle water bottles.

Bottled water company spokesperson: Plastic water bottles are unfairly targeted by environmentalists. They represent only a small fraction of the amount of waste in landfills and an even tinier fraction of the amount of petroleum used every day. There are many other plastic containers in people’s refrigerators that should be recycled yet water bottles have gotten all of the bad press. Plastic bottle production is responsible for only one third of a percent of the energy consumption in the United States. If the bottles were recycled properly, there would be less petroleum consumed in making water bottles.

There are many more benefits to using plastic water bottles than there are disadvantages. They are lightweight and reduce shipping costs of beverages that were formerly contained in glass bottles. The plastics industry is constantly working on making plastics that are even lighter weight and biodegradable. Some beverage companies are now using recycled plastics in making the new bottles and have introduced innovations such as being able to make the bottles more compact for easier recycling.

Water bottles end up in landfills simply because there are limited recycling opportunities in communities. People buy bottled water because it is a healthy choice when they are on the go. The real issue is getting the water bottles to recycling centers. Many recycling centers in the United States have a shortage of the plastic materials they could use to make so many other products. Recycling bins need to be placed in parks and schools and people need to get in the habit of taking their water bottles home to recycle when recycling bins are not available. It does not make sense to force a bottled-water deposit law on people because it just means people will end up paying more for their bottled water.

We should be celebrating the fact that people are making health-conscious decisions. We are reducing caffeine and sugar in our diets. Some people prefer the taste of a particular brand of bottled water over tap water and they should be able to have that choice. Other people do not have safe water to drink from their taps. We need to continue to make healthy choices as convenient for people as possible.


1. What points did you agree on that the environmental spokesman made? Disagree?

2. What points did you agree on that the water bottle industry spokesman made? Disagree?

3. Do you think any laws should be enacted to reduce the number of plastic water bottles in landfills? Explain.

4. Are there any changes in habit that you or your family could make to reduce the number of water bottles that are thrown away? Explain.

More to Explore

Container Recycling Institute: Bottled Water
Bottle Bill Resource Guide

African Elephants and the Ivory Trade

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Millions of elephants once roamed the continent of Africa. African elephants, which are the largest terrestrial animals, dig watering holes, trim vegetation, disperse seeds, and help trees germinate as they wander. Like so many species, African elephant populations have suffered from habitat destruction and conflict with humans. But sadly, the biggest threat to elephants today is poaching, or illegal killing. Driven by a soaring ivory market in Eastern countries, elephants are being hunted and slaughtered for their tusks like never before. Tens of thousands of elephants were killed in 2012 and the numbers appear to be rising.

Elephant tusks are actually modified teeth. Unlike Asian elephants, both male and female African elephants have tusks, and so are equally at risk. The tusks continue to grow over the course of the animal’s life, and may reach 5 to 8 feet in length. African elephants use their tusks mainly for digging, stripping bark, and to defend themselves. People use elephant tusks to create carved objects such as statues or jewelry.

In 1989, the Convention on International Trade and Endangered Species (CITES) placed a worldwide ban on ivory trade. The ban appeared to be making a difference, and many elephant populations began to rebound. Replacement materials have been found to make products that were once made of ivory such as piano keys and billiard balls. But a loophole was introduced when it was determined that ivory from elephants that died of natural causes could be sold legally. In 2008, Africa sold 73 tons of ivory to Asia, where it was used to carve religious statues and other objects.

The result has been a dramatic increase in the demand for such ivory products, and where there are riches to be made from such a demand, there are people willing to fill it. Because monitoring vast wildlife preserves and enforcing anti-poaching laws is difficult to do with the limited resources that African governments have to devote to the cause, elephants continue to be killed and the ivory is smuggled out of Africa. In Asia, dealers can make it rich as they sell the ivory and carvings, often under the disguise of legally obtained or artificial ivory.

The outlook for the African elephant is bleak as things currently stand in the ivory market. In China, for example, sales of religious products have reached over $15 billion a year, new ivory carving factories have opened up, and students can learn ivory carving at the Beijing University of Technology.


1. Draw a diagram describing how economics relate to ecology in this case study.

2. The end-buyers of ivory products may not be fully aware that they are indirectly supporting the killing of elephants. Write the content for a simple educational web page to educate consumers.

3. The World Wildlife Fund (WWF) believes that involved governments need to increase anti-poaching law enforcement. Brainstorm steps a nonprofit organization or multinational organization such as the United Nations could take to help them achieve this goal.

More to Explore

World Wildlife Federation Elephant Page
African Elephant Conservation Fund

Medicine From Nature

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The bountiful diversity of life on Earth is slipping away at an alarming rate. By one estimate, 40 percent of all species are endangered. Why does it really matter how many species exist on Earth? Of all the arguments for why we need biodiversity, there is one selfish reason that should be most relevant to anyone who has ever been sick or in pain. It is that most of our medicines come from biodiversity. They are first “invented” by plants or animals over millions of years of evolution, and only then adapted by us. According to a recent study of more than 1,000 drugs approved over a 20-year period, not a single one was truly synthetic. All were derived from, or at least based on, a natural source. Plant toxins have long been a source of medicine for people. Now scientists are discovering that animal toxins, such as those in the venom of species from snakes to spiders to bees, may prove to be useful as well.

Venom is really modified saliva. A complex concoction, venom is made up of toxins and hundreds of other ingredients. Each venomous species’ concoction is unique, consisting of molecules modified to attack very specific targets. For example, some toxins target red blood cells, others the muscle cells of the heart, others nerve cells, and still others target fat cells. Because they are so targeted, drugs based on these toxins have the potential of causing very few side effects.

Such is the case with the first drug developed from snake venom. Scientists noticed that workers in banana plantations bit by the Brazilian pit viper would collapse suddenly from a drop in blood pressure. They developed a drug based on the viper’s venom to intentionally lower blood pressure—it was the first ACE inhibitor. Today ACE inhibitors are widely used to treat high blood pressure and cause fewer side effects than any other blood pressure medication.

Dozens of other toxin-based drugs have since been invented, with many more currently under development, to treat everything from diabetes to asthma. A toxin from the Chilean Rose tarantula may stop heart attacks. Cone snail and box jellyfish toxins may lead to non-addictive painkillers. Sea anemone toxins may treat paralysis and multiple sclerosis. And a drug based on a giant yellow Israeli scorpion toxin may deliver radioactive iodine to brain tumor cells, effectively removing tumor cells left behind after surgery.

Despite the great potential of toxins in medicine, our knowledge about them, even for known species, is minimal. Only now are scientists beginning to scour the Earth, collecting the genetic sequences of toxins for storage and possible use before they could be lost forever.


1. In order to justify the allocation of resources to biodiversity preservation, some organizations are attempting to quantify the value of biodiversity. Using the 2006 data from the report in this link, or a more recent source, estimate the annual value of nature-based pharmaceuticals. Assume that 63 percent of the market is derived from natural sources.

2. Despite the potential for medical applications, only a small fraction of Earth’s species have been explored for this purpose. Speculate on the reasons for this.

3. The toxins of many marine invertebrates including cone snails, jellyfish, sea anemones, and sea stars may lead to new medicines. Research and describe one of these applications.

4. Use your research from Question 3 to write an argument persuading the public to value marine biodiversity.

More To Explore

Venoms as a Platform for Human Drugs: Translating Toxins into Therapeutics
The Venom Cure PBS Video

The Native Species That Could

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When an “exotic” species is brought to a new environment and makes its home there, everything changes. Many native species die out as their biotic and abiotic resources are taken over or are fundamentally altered. Enormous damage is done as the invasive species spreads faster than people can eradicate it. Examples of destructive invasions can be found everywhere in the United States, from zebra mussels in the Great Lakes to kudzu in the South. However, new evidence is providing the hopeful message that not all native species necessarily succumb to invasions. As a striking example of evolution in action, scientists have found that some native species are adapting to the changes brought on by invaders, and can do so rapidly.

For example, toxic cane toads were brought to Australia in 1935. Today, less than 30 generations later, some species of snakes have evolved as a response. Australian black snakes from toad-invaded areas have acquired an increased resistance to the toad’s toxin. In addition, the black snake and other species, including the death adder, have evolved smaller head sizes in areas where the cane toad is present. The snakes with smaller heads cannot eat toads that are large enough to kill them, so natural selection has favored those with smaller heads.

Likewise, some plants in invaded areas have shown signs of adaptation. Cheatgrass is an invasive grass that has spread across the deserts of the Intermountain West. It sprouts earlier in the spring than the native grasses and saps nutrients from the soil. Cheatgrass is extremely flammable and has led to an increase in wildfires in the region. Once a fire has wiped out the existing vegetation, the invasive grass spreads farther across the open land.

Scientists compared several hundred native perennial grasses from communities with and without cheatgrass. Each plant was divided in two and brought to a greenhouse. One plant of each pair was grown with cheatgrass to measure its ability to survive and compete. They found that plants from the invaded areas had adapted by sprouting earlier, and two species began flowering earlier in order to better compete with the cheatgrass.

In another study, scientists found that a native grass called big squirreltail has adapted to cheatgrass invasion by developing smaller shoots and larger roots. The altered squirreltail roots take back the nutrients that cheatgrass has been stealing from the native plants and suppress the cheatgrass’ growth.

Other scientists have even found evidence of coevolution, in which both the native species and the invasive species have evolved in response to each other. Garlic mustard is a stubborn invasive herb that releases a compound called sinigrin. Sinigrin kills fungi that native plants need to absorb nutrients from the soil. However, a native species known as clearweed has shown increased resistance to garlic mustard. Garlic mustard has, in turn, adapted by releasing more sinigrin in areas where more native species are present. What may at first appear to just be a clump of boring-looking weeds, may actually be an example of a dramatic evolutionary arms race in progress.

1. Just because one population of a native species has evolved a response to an invader doesn’t mean another will, given the chance. How might strategic transplantation be used in the management of invasive species? Give a specific example.

2. Consider another invasive species that you already know about. Design an investigation to find out if any native species are adapting to the presence of the invasive species.

3. How could scientists determine whether genetic changes have occurred in adapted native species? What might be done with this information?

4. Speculate on the long-term consequences of native and invasive species evolution.

More to Explore
 Native Plants Evolve to Fight Off Invading Species
Coevolution and Evolutionary Arms Races
Native Species Fight Back: First Evidence of Coevolution Between Invasive, Native Species
Native Perennial Grasses Show Evolutionary Response to Bromus tectorum (Cheatgrass) Invasion

Rock Snot Does Not Rock

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Nicknamed “rock snot” because of its slimy green appearance, the single-celled protist, didymo (Didymosephenia geminata) is invading rivers across the country. Didymo has been historically confined to cold, clear, low-nutrient streams in northern Europe, Russia, and northern North America. Recently, a new strain has been found in warmer climates and nutrient-rich waters.

Didymo can survive for months in fishing equipment and has been unintentionally carried by humans from location to location. Even a single microscopic cell of didymo can be enough to start a new colony. In this way, didymo has been spread to an increasing number of states in the U.S., and even all the way to New Zealand.

Didymo can form carpet-like “blooms” that wreak havoc on river systems. The blooms consist of stalks that the didymo uses to attach to rocks on the bottom of a riverbed. The didymo eventually die off but vast masses of stalks persist, choking out the native species of algae and plants, disrupting insect habitats, and affecting their fish predators. Didymo can also clog water intake pipes such as irrigation pipes or municipal water pipes.

The presence of didymo has been confirmed for the first time in the Youghiogheny River in Pennsylvania. Your task is to assume the role of one of the following members of a Pennsylvania community:

Trout Fisherman
Environmental Activist
Aquatic Biologist
Fish and Boat Commission Director
Department of Conservation and Natural Resources Official
Local Resident
Bureau of State Parks Director

You will attend a community meeting to discuss what should be done about the existence of didymo in Pennsylvania. Use the research questions below to help you prepare for the meeting. As you research and conduct your meeting, consider how the didymo issue affects you specifically in your role.


1. What should or can be done to eliminate the existing didymo populations from the Youghiogheny River?

2. What specific laws or regulations, if any, should be put into place to prevent the further spread of didymo?

3. What public information may help prevent the further spread of didymo and how should it be distributed? If signage is used, where should it be placed?

4. How are other states handling this issue?

More to Explore

Rock Snot Found in Pennsylvania
USDA Invasive Species Profile for Didymo
West Virginia Best Practices

Wind Energy and Land Rights

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In 2008 the U.S. Department of Energy released a plan for 20 percent of energy to be wind-generated by 2030. Finding land to place wind turbines (windmills), however, is difficult. Long-term studies must be done to make sure there is enough wind to generate electricity. The land must be in reasonable reach of power lines and have road access. Developers also must be fairly sure that future development nearby will not obstruct the wind. Placement of wind turbines also needs to be in an area where it will not interrupt air, television, and microwave signals.

A wind energy developer wants to place 30 turbines along a mountain ridgeline in between two rural towns. The developer has leased the land from a single private owner, who approves of the project. The majority of the townspeople of both nearby towns also approve of the project. It will bring work to the area where there are not many jobs, although most of the work will be temporary construction projects placing the turbines. The townspeople will also receive tax benefits once the turbines are running, and their electricity bills will decrease. Most residents also feel that the rows of spinning turbines in the distance will enhance the landscape and represent progress in an area where there are few signs of modern technology.

The wind developer has spent two years getting all the permits needed to begin construction. However, just below the area where the turbines are to be placed are large vacation homes owned by wealthy people that have chosen to locate their second homes in an area where they can have unobstructed views of the majestic mountains. Many of their homes have been built with large picture windows facing the ridgeline where the turbines are planned to be placed. In other cases where turbines are located near homes, wind developers have given nearby homes central air conditioning units so residents do not have to open their windows when the turbines are running. These homes, however, already have central air conditioning and the residents are not won over by offers of money to compensate for their loss of pristine mountain views. They believe that the view of the turbines will lower their property values below what they originally paid to build their homes.

The small group of homeowners has formed a group to oppose development. They have hired an environmental consultant company and have filed a lawsuit that has held up the project. The lawsuit centers on an access road that will have to be constructed to move the heavy equipment to the proposed wind turbine site. The road must cross over several streams. The streams will need bridges built over them, which will require the riverbanks to be altered. Water flow may change and possibly affect species within the streams. If necessary, these homeowners are ready to file a second lawsuit claiming the access road would break up habitat for bears and other wildlife in the area. The homeowners are also looking into possible effects wind farm development might have on the bird and bat populations in the area.

The local townspeople are angered that, though they approved the wind farm project through a vote and permits have been approved for work on the project to start, a small group of “outsiders” that live in the area only a few months a year have stopped a major project that could bring money to their community. The local government has hired its own environmental consultant that recommends proceeding with the project due to the benefit of wind energy in slowing global climate change. Wind energy is considered a clean, non-polluting form of energy due to its low carbon emissions.

All the publicity from the lawsuit has caused a private non-profit environmental conservation group to take notice. It has offered to purchase the land to prevent development and preserve the landscape as scenic open space. If the conservation group purchased the land, it could be used for recreation but would not be developed for any use in the foreseeable future.


1. Who are the stakeholders in this scenario?

2. If wind power was a major source of energy in the U.S, there would likely be a measureable decline in air and water pollution, and a certain decline in our reliance on imported fossil fuels for our energy needs. What obstacles to the development of wind-powered energy were brought up in this scenario?

3. There are a number of different environmental concerns in this case. What are the potential local and global effects of wind-power development in this case, both positive and negative?

4. The view of a field of turbines is pleasing to some and displeasing to others. In this case, townspeople thought it would enhance the landscape while the vacation homeowners thought the view would lower their property value.  What is likely the reason for their major differences of opinion?

5. Should a wind turbine field be developed in this area? Justify your reasoning.

More to Explore

How is wind used to generate electricity?
How are sites for wind energy development picked?
What are the United States federal and state policies surrounding wind energy development?

The Great Pacific Garbage Patch

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In 1997, Charles Moore had just finished a sailing race in Hawai’i and decided to take a different route traveling back to California than most sailors do. He sailed through a region that is sometimes known as “the doldrums” due to the region’s light winds. More scientifically, the area is called the North Pacific Subtropical Gyre (NPSG). A gyre is an area of circulating currents that is usually very calm at its center. Moore sailed through the eastern region of the NPSG. He might have expected some slow travel though the area, but what he didn’t expect was to be surrounded by pieces of plastic floating in the water. His discovery of what is now known as “The Great Pacific Garbage Patch” led Moore to dedicate his life to educating people about the role all of us play in literally trashing the oceans.

Moore isn’t the only person interested in The Great Pacific Garbage Patch. Since its discovery, scientists around the world have taken notice. This region has few big mammals or predatory fish, but it is rich in phytoplankton and zooplankton. It also contains what amounts to millions of pounds of trash, most of it plastic. To make matters worse, there is more than one patch. The Great Pacific Garbage Patch is made up of both the Western Pacific Garbage Patch, located between Hawai’i and California and another, the Eastern Pacific Garbage Patch, located between Japan and Hawai’i. Running between the two patches is a thin, 6,000 mile current called the Subtropical Convergence Zone. This zone acts like an interstate highway, carrying trash along the current to the two gyres that make up the eastern and western garbage patches.  The Subtropical Convergence Zone, unlike the garbage patches, is rich in many types of sea life. In addition, there is also a garbage patch in the Atlantic Ocean. In fact, there are five or six major gyres in the world’s oceans, so it is likely that there are even more garbage patches out there.

Where is all this garbage coming from? Some comes from the fishing industry. Abandoned fishing nets are dangerous to sea life and are estimated to make up about 10 percent of the trash in the oceans. Somewhere around another 10 percent is from the shipping industry. Accidents at sea cause entire shipping containers full of goods to be overturned into the ocean. The world’s military ships and recreational boaters are to blame for a percentage of the garbage too. But much of the trash comes from land. The 2011 tsunami in Japan has added to the ocean debris. Beachgoers that leave behind trash and belongings in the sand also are to blame. And all of the plastic that we use, from laundry detergent bottles and toothbrushes to grocery sacks, typically gets tossed into a landfill. Winds blow and carry trash into streams and rivers, or blow out of garbage trucks and eventually blow offshore. It can take six years for trash from the west coast of the United States to make it to the Western Pacific Garbage Patch. It takes about a year for trash from Asia to reach the Eastern Pacific Garbage Patch. Regardless of the time at sea, plastic does not disintegrate. Microbes, which are responsible for biodegrading most materials, do not consider plastic as food. Plastic does, however, photodegrade. That means it breaks down in the sunlight. Most non-plastic trash will settle down to the ocean floor. Plastic, however, floats and is carried along the currents, exposed to the sun all the while.

Because the plastic breaks down in ever-smaller pieces, by the time it reaches the Great Pacific Garbage Patch, most of it is no longer identifiable. The garbage patches cannot even be seen from aerial photos, because the pieces are so small and many float below the surface of the ocean. This aspect also makes cleaning up the patches almost impossible. The currents change with the seasons, making even the size and shape of the garbage patches hard to measure and their locations tough to pinpoint. Scooping up the plastic with nets would also remove at least as many plankton as plastic pieces from the ocean, and plankton are the foundation of the marine food chain. In fact, seabirds such as albatrosses often think the plastic is plankton or other food, and they feed it to their chicks. Many thousands of albatross chicks are killed every year by ingesting large amounts of the tiny pieces of plastic. The plastics can also contain hazardous toxins from the colorants and plasticizers used to produce them. They also absorb toxins already in the ocean, concentrating them and introducing them to our food supply when we eat fish that has eaten plastic. Science has many questions yet to answer about the Great Pacific Garbage Patch and other marine garbage patches, but everyone is clear on one point. Plastics do not belong in our oceans.


1. Any attempt to clean up the Great Pacific Garbage Patch would be extremely costly and almost impossible. Also, no country wants to be solely responsible for the task since the trash is not within the boundary of any nation. What actions can every person take to prevent more trash from making it to the ocean, even if they do not live by a coast?

2. There have been claims that the Great Pacific Garbage Patch is larger than the United States, while other researchers claim that the actual trash accumulation is closer to 1 percent the size of Texas. What are factors that make the garbage patch so hard to measure?

3. Scientists studying the Atlantic Garbage Patch were surprised at research findings that it has not increased in size since the mid-1980s. What are factors that might explain it has remained the same size for the past 30 years?  What are possible factors in their research methods that might make these results inaccurate?

4. Another effect of having tiny bits of plastic floating on and near the ocean’s surface is that it blocks out the sunlight for the phytoplankton, possibly threatening their populations and lowering the amount of global oxygen available. What could be the effects of a significant decrease in phytoplankton on marine food chains? Use specific examples in your answer.

5. Before the plastics break down into tiny pieces, they still cause many hazards to sea life. What hazards might trash such as plastic bags and soda rings cause to sea turtles, seals, and other sea life?

6. Some scientists feel that the claims by other researchers about the Great Pacific Garbage Patch are exaggerated. What would be the possible danger to exaggerating findings to the public in order to get their attention?

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Why is the world’s largest landfill in the Pacific Ocean?
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Don’t Take That Banana for Granted

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“What’s a banana?” is not a question you are likely to hear anytime soon. But future generations of children may not grow up eating bananas like we did. If the world’s large-scale banana crops cannot be sustained, the slender fruit could someday look more like the exotic food that it truly is than a cheap American staple.

Given the way we eat bananas, you would think they were grown across the American plains. Americans eat more bananas than any other fruit. And we pay less for them than most other fruits. But most of our bananas come from Central America, and they are not at all easy to cultivate. Most of the thousands of banana varieties in existence are too bland, ripen too quickly, or yield too small a bunch to make it in the global market.

One variety, the Cavendish, makes up 99 percent of the banana export market. The Cavendish has what it takes—but just barely. Cavendish bananas must be picked while they are still green, they bruise easily during shipping, and they survive only two weeks once they’re off the tree.

Perhaps the biggest problem with our reliance on the Cavendish is that the banana plants they come from are all genetic clones. Without genetic diversity in the population, they are extremely vulnerable to disease. Diseases such as Black Sigatoka have led to the heavy use of expensive fungicides and pesticides to keep the crops alive. The cost of spraying is almost $1000 per acre and the plants must be sprayed almost every week.

And then there are the diseases that are not controllable by sprays. One such disease, Tropical Race Four, is a soil-born fungus that has already destroyed Cavendish populations in Indonesia, Malaysia, and Taiwan, causing tens of millions of dollars’ worth of damage. Most scientists agree that it is just a matter of time before it spreads to banana crops grown in Africa and Central America.

It would not be the first time a fungus has knocked out the global banana supply. In the 1960s, a similar fungus called Panama disease caused the Cavendish’s predecessor, the Gros Michel, to essentially go extinct. The Asian Cavendish was found to be resistant to Panama disease and became its replacement. Finding a potential replacement for the Cavendish has been a challenge.

Scientists led by Juan Fernando Aguilar of the Fundación Hondureña de Investigación Agrícola (FHIA) in Honduras are attempting to create new banana varieties through laborious cross-breeding techniques. In several labs elsewhere around the world, genetic engineers are working on creating disease-resistant bananas through genetic manipulation.

At this point, you may be wondering how bananas came to be such big business in the first place. In the late 19th century United Fruit Company (now Chiquita) built railroads through Central America in exchange for thousands of acres of rain forest land, which would be cleared for banana growing. United Fruit Company and others did an unprecedented job of marketing bananas to Americans. They reportedly even hired doctors to convince families that bananas were good for their children. Their tactics  worked—by the early 1900s, Americans were crazy about bananas. Banana peel litter actually contributed to the development of the first waste-removal networks in cities. The cost of bananas was kept down by poor wages and working conditions in the banana fields, and lack of health care and other rights for fieldworkers.

The question now is how to sustain the banana habit that has been created, or if we even should.


1. You are leading a team that is working on breeding the “perfect banana.” List the criteria you would use to evaluate potential new breeds.

2. Assuming there is no such thing as the “perfect banana,” which of the above criteria would you be willing to compromise? Defend your decision.

3. What might be the consequences of compromising the criterion you chose?

4. Which qualities of a banana would you be willing to compromise as a consumer? Explain.

5. Is the banana a good candidate for genetic manipulation? Why or why not?

6. Research and explain the difference between organic and fair-trade bananas.

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The FHIA Banana Program

Banana Biology