7doc.docx

Can Cambodia heed a warning from history? Phenomenon Silently, a fishing canoe leaves a floating house on the Cambodian lake called Tonie Sap In southeast Asia. Its target? The same fishes, from the same lake that fed the ancient Khmer Empire and its capital Angkor a thousand years ago. But that fi...

Can Cambodia heed a warning from history? Phenomenon Silently, a fishing canoe leaves a floating house on the Cambodian lake called Tonie Sap In southeast Asia. Its target? The same fishes, from the same lake that fed the ancient Khmer Empire and its capital Angkor a thousand years ago. But that fishery, which was productive for hundreds of years, is in danger of collapse today ... for some of the same reasons that led to the fall of Angkor and the Khmer empire, centuries ago. What kind of trouble is the fishery in? That floating house isn't in trouble. It always floats during the rainy season, when Tonie Sap is in flood stage. Local residents welcome the annual rains, which cause the lake to expand to five times its dry-season size, flooding sur­ rounding wetlands and forest. Nutrients in the floodwaters power the aquatic food chain and enrich wetlands and forests This complex ecosystem is home to an incredible diversity of fishes-lots of them! More than 350,000,000 kilograms of fish are harvested each year. This incredibly produc tive inland fishery, has been feeding millions of people globally. But Tonie Sap is in trouble. Fish catches are dropping. While some people move to the area to fish or farm, others move to cities for jobs as fish disappear. Land around the lake is being converted from forest to rice paddies. Many fishes feed and breed in the seasonally flooded forest, so cutting them removes vital habitat. Hydroelectric dams are planned for rivers that flow into Tonie Sap, because most people in the region have no electricity. But in addition to interfering with water and sediment flow, dams would block migrating fishes. Climate change adds to these stresses, creating what investigator Les Kaufman and his colleagues know that history offers reason to worry that all these changes could cause an ecological disaster. Not far from Tonie Sap lie the ruins of Angkor. Once housing more than a million people, Angkor was the largest city in the preindus­ trial world. Today the city lies in ruins, except for its famous temples. Some temples are decorated with carvings of fishes, offering evidence that Angkor depended on Tonie Sap for food. Then, about 600 years ago, Angkor was abandoned. What happened to Angkor back then? Could it happen again now? Tonie Sap is an example of the challenge of providing three basic human needs: water, food, and energy. Kaufman and his colleagues are gathering data and creating sophisticated models that combine ecological and socioeconomic data. The models predict possible futures for the ecosystem under different regional develop­ ment plans. Some of these projections show possibilities of ecosystem collapse. How might planners avoid those outcomes? What would the warning signs be? How could a model guide planning? Humanity Global System change An astronaut's view of Earth as an island of life in empty space fit well with the term "spaceship Earth." Until recently, we could think of ourselves simply as passengers on our planetary spaceship. Why? Because we thought global systems worked like a spaceship's life­ support systems. We knew that human activity had affected local ecosystems. But we thought global systems were too big for us to change and would function regardless of we did. We were wrong. Humanity's Global Impact Why were we wrong? How can we wrap our heads around the fact that human activity is causing significant changes in several global systems? The Understanding Global Change model we've been building can help. But first we need to understand how, and why, each of us impacts the environment, and how the size of our global population and technology amplify that impact. Ecological Footprints Let's start with what ecologists call your ecological footprint. Your ecological footprint is the total area of healthy­ land and water ecosystems needed to provide the resources you use, and to absorb wastes you produce. As Figure 7-1 shows, your footprint includes all the resources that enable you to live as you do. Energy is used for transportation, as well as to heat our homes. Growing food requires land and fresh water. Everything you buy-from clothes to cell phones-is produced using energy and materials that come from somewhere. You also produce wastes including sewage, trash, and greenhouse gases. National Footprints This world map shows each country in proportion to its ecological footprint. The United States has an ecological foot­ print roughly three times the world's average. By contrast, the African nation of Zambia has a footprint a little over one fourth the global average. Compare each country's "foot­ print" size to its actual size on the smaller m p below. National and Global Ecological Footprints There is no universally accepted formula for calculating ecological footprints. Still, we can make useful comparisons among footprints of people in different countries, as shown in Figure 7-2. To determine a country's ecological footprint, researchers calculate the footprint of a typical citizen and .multiply that by the size of the population. According to some calculations, the average American has an ecological footprint roughly three times larger than the global average. An average American uses almost twice the resources of an average person in England, more than twice the resources used by an aver­ age person in Japan, and almost six times the resources used by an average person in China. Now think, not just about your foot­ print, but about the footprints of nearly 9 billion people together. That incredible amount of human activity is what drives changes in global systems. Describe What is one way to calculate the ecological footprint of a country? I Calculating Ecological Footprint Problem How can you calculate your use of natural resources? In this lab, you will determine what your ecologi­ cal footprint is regarding three types of natural resources: water, land, and fossil fuels. Then, you will explore ways to effectively reduce your eco­ logical footprint in one of these areas. You can find this lab in your digital cours The Age of Humans Humans have affected local environments for a long time. Ancient civilizations in China, Southeast Asia, Central America and South America cut down vast forests to build cities and farms. Even the most remote parts of the Amazon basin were changed by human activity long ago. But that was all "local stuff." Our effects on global systems started growing more rapidly during Europe's Industrial Revolution in the 1800s. That's when a series of brilliant inventions· harnessed fossil fuels to power machinery. Railroads and other forms of transportation connected cities around the globe. Mass production began and spread. And that was just the beginning of the change. The Great Acceleration The greatest change in humanity's relationship with Earth began during "The Great Acceleration" in the 1950s. What was accelerating? Just about everything related to humanity and our impact on the environment, as shown in Figure 7-3. Humans burned more fossil fuels. We farmed more land enriched with more fertilizers and we caught more fish, so we could feed more people. Medical discoveries saved millions of lives. Within a single lifetime, the well-being of millions of people improved dramatically. Death rates fell worldwide. Birth rates stayed high, so global population grew rapidly. Advancing technol­ ogy was used by more people, multiplying our impact on local and global systems. The Great Acceleration {1950-2010) Sources: (1) Olivier Rousseau, IFA; IFA database. (2) A Grubler, International Institute for Applied Systems Analysis (IIASA); Grubler et al. (2012). (3) M Florke, Centre for Environmental Systems Research, University of Kassel; Rorke et al. (2013); aus der Beek et al. (2010); Alcamo et al. (2003). (4) Mack zie et al. (2002). The Anthropocene Global systems are driven by geological, chemical, and physical processes, along with biological processes such as photosynthesis and respiration. At first, human activity was a small part of those biological processes. Today, human activities drive measurable changes in several global systems. We have altered roughly three quarters of all land outside polar regions and mountain ranges, as shown in Figure 7-4. We move more sediment and rock every year than is moved by erosion and all the world's rivers. We've dramatically altered the global nitrogen cycle by fixing and distribut­ ing vast quantities of nitrogen for fertilizer. By burning fossil fuels, and through other activities, we've increased greenhouse gases to concentrations higher than Earth has seen for more than a million years. Given the scale of those activities, and given how quickly they've accelerated, how could anyone imagine that we're not affect­ ing global systems? As we discuss global effects of human activity, remember that human causes of global change occupy a larger part of our model's outer ring than non-human causes. Given our new role as a the most powerful source of global change, many scientists call the time period we're living in the Anthropocene. The Anthropocene, or "age of humans," is the period during which human activity has become the major cause of global change. Anthromes The continental United States' human-altered biomes or anthromes, are shown on this map. Understanding and Modeling Global Change The Great Acceleration "promoted" us from passengers on space­ ship Earth to ,,crew." There's just one problem. We've grabbed the controls-but don't know how they work! We need to write an operating.manual ourselves now ... and quickly! How do we begin? To plan for humanity's future, we need to understand the best available scientific data on how Earth systems work, and to build a model'that shows how both human and nonhuman causes of change are affecting those systems. The full Understanding Global Change model (UGC), is shown in Figure 7-5. Imagine that this graphic represents spaceship Earth's "control panel." Pushing "buttons" in the outer ring is like hitting an accelerator, stepping on a brake, or turning a steering wheel. Each action affects earth systems in the middle ring and causes measurable changes in the inner circle. Thinking about the model this way will help you make cause-and-effect connections among phenomena, and better understand the impacts of human activities on natural systems. Global system processes and phenomena occur in the hydro­ sphere, atmosphere, geosphere, biosphere, and across two or more of those "spheres." This model includes most of what some scien­ tists call the cryosphere ("frozen" sphere) within the hydrosphere. Biogeochemical cycles and other global system processes occupy the model's middle ring. Plant and animal populations, communities, ecosystems, and their interactions with global systems are also in that middle ring, mainly in the biosphere. Causes of global change that affect those systems are in the outer ring, with nonhuman causes in the lower portion, and human causes in the upper portion. Measurable changes in Earth systems that are produced when causes of change affect those systems are in Earth systems that are produced when causes of change affect those systems in the model's inner circle. Anthropogenic Global Change and its effect How do human activities change the atmosphere and climate? How do changes in the atmosphere drive climate change and other changes in global systems? How do the ways we use land drive change in global systems? How do humans directly effect populations? What kinds of pollutants are drivers of global change? Global change can be driven by both human and non-human pro­ cesses. Most non-human causes of change operate very slowly, on timescales of thousands to millions of years. Today, human causes of change affect global systems more rapidly, producing measurable changes on time scales as short as years or decades. Some human causes of change are now more powerful than non-human causes of change. Human Causes of Global Change Humanity's total ecological footprint includes activities that affect global systems and drive measurable changes in those systems. Human activities affect global systems by changing the com­ position of the atmosphere in ways that change climate and ocean chemistry, by changing the way we use land, by over­ harvesting some species, by introducing species to new envi­ ronments, and by producing pollutants and wastes that include plastics. These actions create stress on organisms and ecosystems that threatens biodiversity and ecosystem services. Stress caused by all human activities together is much more powerful than the stress caused by any singTe activity. In addition, a single activity, such as converting biomes to anthromes or burning fossil fuels, can affect several global systems. As we discuss each of these activities, keep referring back to Fig re 7-5 to see how it fits into the UGC model. Changing the Atmosphere Human activity is changing Earth's atmosphere faster than it has changed over the entire history of life. Some activities raise con­ centrations of greenhouse gases, driving climate change. Other activities release different gases, causing other effects on global systems. Burning Fossil Fuels Quantitative data confirm two scientific facts. These are that atmospheric carbon dioxide concentration have been increasing since the Industrial Revolution, and that cur­ rent concentrations are higher than they have been for more than a million years. Other data confirm that most of that "extra" carbon dioxide is released by-burning fossil fuels. Burning fossil fuels also releases several forms of nitrogen that can travel over long distances through the air in dry form as tiny particles or dissolved in water droplets. Because nitrogen is a limiting nutrient for primary produc­ ers in some environments, nitrogen enrichment from burning fossil fuels can affect growth of land plants or cause algal blooms. Climate Change Climate change is defined as measurable long­ term changes in averages of temperature, clouds, winds, precipita­ tion, and frequency of extreme weather events such as droughts, floods, major storms, and heat waves. Recall from Chapter 3 that the climate system is powered by the total amount of heat retained within the atmosphere and is shaped by the distribution of heat between the equator and the poles. Higher concentrations of green­ house gases, such as carbon dioxide and methane, trap more heat in the biosphere and cause global warming, which drives climate change. Global warming is the increase in average global tempera­ tures. Changes in the glob I distribution of heat affect winds, ocean currents, and other parts of the global climate system in ways that change patterns of precipitation and other environmental factors. Now recall that organisms have tolerance ranges for environ­ mental conditions. If climate change alters environmental conditions beyond organisms' tolerance ranges, they must adapt, move to more suitable areas, or face extinction. For similar reasons, climate change has major impacts on agriculture. Crop plants have tolerance ranges too. So, if an area gets warmer and drier, crops that grow well in a particular place now may not grow well there us in the future. Increasing temperature also effect marine life. You will learn about climate change and its effects in the next lesson How Does Acid Affect Shells? Vinegar is a solution of acetic acid. Mix vinegar and water in 5 beakers. Put only water in one beaker, only vinegar in another beaker, and mixtures of varying concentrations iR the other beakers. Label each beaker with its contents and the concentration of vinegar {if appropriate). Place 6 tb 10 crushed pieces of egg shells in each beaker. Wait one day. Then pour out the liquid from each beaker, and place the egg shell pieces on a paper towel. Examine the egg shell pieces. ANALVZE AND CONCLUDE Observe How did vinegar - affect the egg shell pieces? Make a chart to record your observations. Draw Conclusions Egg shells are made of cal­ cium carbonate. How could ocean acidification affect corals, lobsters, snails, and other marine organisms that also have skeletons or shells made of calcium carbonate? Construct an Argument How could ocean acidi­ fication become a severe problem? Use evidence and logical reasoning to support your answer. Acid Rain Burning fossil fuels also releases sulfur dioxide (S20) and nitrous oxides (N20) that dissolve in fog or raindrops to form sulfuric acid and nitric acid. This creates acid rain, fog, and snow. Combined with other airborne pollutants, acid rain damages plant leaves and harms roots by releasing aluminum and other metals from some soils. Soil acidification can also interfere with bacterial qecay, altering nutrient cycling. Acid rain can also cause acidification of fresh water that kills aquatic organisms from algae to fishes. Ocean Acidification Researchers have compared the amount of carbon dioxide accumulating in the atmosphere to the amount released by burning fossil fuels. They found that atmospheric car­ bon dioxide was not increasing as much as expected, given the, amount of emissions. Where was the "missing" carbon dioxide? In the oceans! As carbon dioxide concentration in the atmosphere increases, more and more of it dissolves in seawater. There, the extra dissolved carbon dioxide drives a chemical reaction that produces an acid, as shown in Figure 7-6. Ocean acidification poses serious prob­ lems for marine life. Many marine organisms, from plankton to corals and shellfish, remove calcium carbonate from seawater to build their skeletons. As seawater becomes more acidic, these organisms expend more energy to build those skeletons, stressing many marine organisms and ecosystems. How does excess carbon dioxide affect marine organisms? Agriculture and the Atmosphere Agriculture is one of the most important and widespread human activities, so it isn't surprising that it affects the atmosphere. Cattle farming and cultivation of rice in flooded paddies release methane, a more·powerful greenhouse gas than carbon dioxicrle. Methane (CHJ contributes to global warm­ ing and climate change. Changes in Land Use It takes a lot of land to provide housing, food, and energy for nearly nine billion people! Human activity has transformed roughly three-quarters of Earth's land surface in several ways and for several reasons. These include agriculture, monoculture, deforestation, and development. Agriculture The dependable food supply provided by agriculture was a key element in fueling the growth of civilization. During the Great Acceleration, agriculture went through changes in technology and farming techniques called the "Green Revolution." The Green Revolution enabled farmers to dramatically increase crop yields to feed the world's growing population. Today, agricultural activities cover more of Earth's land surface than any other human activity. Another key part of the Green Revolution was the use of chemical fertilizers containing nitrogen and other nutrients. High-nitrogen fertil­ izers are produced by industrial processes that fix atmospheric nitro­ gen. This added nitrogen fueled the Green Revolution and helped increase food production. Today, fertilizer manufacture and applica­ tion has more than doubled the amount of biologically active nitro­ gen cycling through the biosphere, dramatically changing the natural nitrogen cycle. Lots of nitrogen "leaks" out of agriculture in soil water runoff. Excess nitrogen in streams and rivers can upset the balance in freshwater and ,marine ecosystems, as shown in Figure 7-7. Toxic Algal Bloom In July 2015, an enormous algal bloom stretched from California to Alaska. One of the algae involved in the bloom produces a toxin that builds up in the food chain and can poison fish, seabirds, marine mammals, and humans. Monoculture One key part of the Green Revolution was a strategy called monoculture, which involves planting large areas with a single highly productive crop year after year. Monoculture enables efficient sowing, tending, and harvesting using machines. These techniques dramatically increa ed crop yields. But large-scale monoculture requires lots of artificial fertilizers and pesticides. When large areas are used for grazing, or to grow monocultures for long periods, fertilizers and pesticides can change soil structure and microbiomes in ways that degrade soil and prevent secondary succession Deforestation/Reforestation Healthy forests hold soil in place, protecting the quality of freshwater supplies, absorbing carbon dioxide, and moderating local climate. When forests are lost, those ecosystem services disappear. Deforestation It's hard to appreciate how much deforestation, or cutting of forests, has altered natural environments. Most of us live in anthromes that haven't been in a natural state for a long time, as Figure 7-8 shows. Between 1620 and 1920, roughly 90 percent of the forests that covered the continental United States were cut for lumber, farming, or both. Deforestation can affect water quality in streams and rivers by altering clarity, taste, and odor. In moun­ tainous areas, deforestation increases soil erosion, which can cause landslides. Deforestation often divides natural ecosystems into frag­ ments, which can cause loss of biodiversity. Natural Regrowth Through Succession Almost anywhere in the United States, east of the Mississippi River, today's forests are secondary forests that grew back after primary forests were cut. This regrowth is possible in the southeast because logged areas can undergo secondary succession. In tropical rain forests, topsoil is thin, and organic matter decomposes rapidly. If small areas are cleared and left alone, secondary succession can occur and restore biodiversity. If large areas are cleared and used for agriculture for more than a short time, regrowth may not be possible. Reforestation Scientifically-informed, grassroots reforestation, guided by long­ term partnership between local communities and the non­ governmental organization Ecologic Development Fund, is restoring the integrity of local watersheds in Totonicapan, Guatemala. Reforestation Scientifically guided reforestation, or replanting of forests, can replace trees that have been cut. Reforestation efforts by local communities around the world are bringing back forests and restoring ecosystem services. Figure 7-9 shows reforestation work by a local Mayan community in Totonicapan, Guatemala, where deforestation had caused local streams and springs to dry up. Those water sources are now returning and supplying clean drinking water. Development/Urbanization As modern societies develop, many people move to cities and to suburbs. Roughly two-thirds of Americans live in urban areas today, and migration to cities is increasing in devel­ oping countries around the world. These dense human communities produce large amounts of wastes. If these wastes are not disposed of properly, they affect air, water, and soil resources. Development also consumes farmland and divides natural habitats into fragments One result of urbanization has been an increase in production of sewage, which includes everything you flush down the toilet or the drain. In some cities, sewage includes runoff from roofs, sidewalks, and streets. Sewage isn't always poisonous, but it does contain lots of nitrogen and phosphorus, as well as drugs and hormones that can affect aquatic organisms. Reasonable amounts of these nutrients can be processed and absorbed by healthy ecosystems. But large amounts of sewage can disrupt nutrient cycles and stimulate the growth of toxic or ecologically damaging blooms of bacteria and algae. Raw sewage also contains microorganisms that can spread disease Habitat Loss, Fragmentation, and Restoration Human­ caused changes in natural habitats can occur in a number of ways and for several reasons. As discussed in Chapter 6, these include habitat loss, habitat fragmentation, and habitat restoration What is the relationship be een habitat size and the number of species that can live there? Direct Human Effects on Populations In addition to activities that indirectly affect plant and animal .popu­ lations, humans have directly interacted with wild species for many centuries. Humans have hunted some terrestrial animals extinction, have overfished both fresh and saltwater species, and have introduced invasive species into new habitats. One result of urbanization has been an increase in production of sewage, which includes everything you flush down the toilet or the drain. In some cities, sewage includes runoff from roofs, sidewalks, and streets. Sewage isn't always poisonous, but it does contain lots of nitrogen and phosphorus, as well as drugs and hormones that can affect aquatic organisms. Reasonable amounts of these nutrients can be processed and absorbed by healthy ecosystems. But large amounts of sewage can disrupt nutrient cycles and stimulate the growth of toxic or ecologically damaging blooms of bacteria and algae. Raw sewage also contains microorganisms that can spread disease Hunting and Fishing Hunting animals for food has been an important part of human culture for thousands of years. When human populations were small, and when hunting served mainly to pro- vide food, our ancestors' actions had relatively limited effects. But as our population has grown, and as technologies used in hunting and fishing have become more sophisticated, these activities have threatened many species with extinction. In addition, many animals are killed in large numbers for sport, for hides, feathers, ivory, or body parts believed to have medicinal properties. Illegal trophy hunting threatens many species, including rhinos, gorillas and elephants. Overfishing is causing dramatic declines in fish populations worldwide. In the United States, endangered species on land, and in both freshwater and saltwater habitats, are protected from hunting and fishing. The Convention on International Trade in Endangered Species {CITES) bans international trade in products from endan­ gered species, but it's difficult to enforce laws in remote areas Invasive Species Recall that organisms introduced to new habitats where they lack predators and parasites can experience exponential population growth and become invasive species. An invasive species is any nonnative species whose introduction causes, or is likely to cause, economic harm, environmental harm, or harm to human health. Some invasive animal species eat animals, while oth­ ers become parasites on native plants or crops. Invasive species of both plants and animals may compete with native species for limited resources, including water, space, food or nutrients, and sunlight. Any of these interactions can drive native species to extinction, and disrupt ecosystem services. Most invasive species are carried to new habitats by human trade and travel. Sometimes, invasives are introduced by accident, as "stowaways" in fruits, vegetables, or plants. Other times,,they have been introduced intentionally, without understanding the problems they can cause. Ecological problems caused by invasive species around the world have grown to the point where they are included as drivers of global change. There are roughly 3000 invasive species in the United States, with over 200 in the San Francisco area alone. Figure 7-10 show some examples of invasive species in California Invasive Species Three invasive species that are common in California include the northern water snake; ailanthus trees, and the brown marmorated stink bug Pollution A pollutant is any harmful material created by human activity and released into the environment. Many pollutants threaten biodiversity. Certain kinds of pollution that were once considered "local prob­ lems" are now known to have global effects. Air pollution is a serious problem in California, which has been ranked as the state with the worst air quality in the country. This situation has led the California to create one of the most aggressive anti-pollution efforts in the nation. Common forms of air pollution include smog, greenhouse gases, heavy metals, and aerosols. Primary sources of water pol­ lution are industrial and agricultural chemicals, residential sew­ age, and nonpoint sources. Roughly one million Californians around the state lack access to safe drinking water. Notice how pollutants fit into the Understanding Global Change mode CFCs and Stratospheric Ozone, Chlorofluorocarbons (CFCs) are industrially produced gases. CFCs belong to a group of chemicals containing chlorine or fluorine and are known as halogens. CFCs once were widely used as propellants in aerosol cans and fire extinguishers, as coolants in refrigerators and air conditioners, and in the produc­ tion of plastic foams. A few decades ago, the use of CFCs was tied to the destruction of ozone in a section of the upper atmosphere called the stratosphere. This high-level ozone, called the ozone layer, absorbs ultraviolet light, acting like a global sunscreen. Beginning in the 1970s, satellite data revealed that the ozone concentration over Antarctica was decreasing, as shown in Figure 7-11. The area of lower ozone concentration was called an "ozone hole." For several years after the hole was discovered, ozone concentrations continued to drop, and the hole grew larger and lasted longer every ye.ar. Ozone Hole In these satellite images, the size and intensity of the blue region increased from 1981 to 1999, indicating a thinning of the ozone layer over Antarctica. The graph shows how the levels of atmospheric halogens have decreased since legisla­ tion was passed to ban CFCs No one could explain this phenomenon until three research- ers made a breakthrough that earned them a Nobel Prize. In 1974, researchers demonstrated that CFCs act as catalysts to destroy ozone molecules under conditions in the upper atmosphere. This research led to hypotheses that were tested in several ways. Research flights over the poles gathered data demonstrating that CFCs combine with ice crystals in frigid air in a way that allows ' sunlight to destroy ozone. Once this research was published and accepted by the scientific community, the rest was up to policymak­ ers and industry-as you will learn later in this chapter. Ground-Level Ozone Ozone in the upper atmosphere is a good thing for us, but not at ground level. If you live in a large city in California, you've undoubtedly seen smog, a gray-brown haze formed by chemical reactions among pollutants released by industrial processes and automobile exhaust.' Smog in Los Angeles is shown in Figure 7-12. Ozone is one product of these reactions. Ozone and other pollutants at ground level threaten human health, especially for people with respiratory conditions. In 2017, Los Angeles, Long Beach, Bakersfield, and Fresno-Madera had the worst smog levels in the country. In response, California has become a national leader in improving automobile emission standards and clean-air regulations. Air quality has improved, but still has a long way to go. INTERACTIVITY Investigate the impact humans have on ecosystems through pollution, farm- ing, hunting, building, and overfishing. Industrial and Agricultural Pollution Industry, science, and technology provide us with the conveniences of modern life. Lots of energy is used to produce and power these conveniences. We pro­ duce most of this energy by burning fossil fuels that release green­ house gases and other pollutants. Since the Industrial Revolution, many industries have discarded wastes from manufacturing and energy production into air, water, and soil. Largescale monoculture increased the use of pesticides and insecticides. These chemicals can enter the water supply in the form of runoff after heavy rains, or they can seep directly into groundwater. This type of pollution is called nonpoint source pollution. Air quality problems in the Bakersfield <!rea are produced by a combination of industrial activity and agricultural production Biological Magnification In the process of biological magnification, the concentration of a pollutant like DDT-represented by the orange dots-is multiplied as it passes up the food chain from producers to consumers Biological Magnification Living systems can absorb and concentrate these chemicals and pollcitants in a process called biological magnification. Biological magnification occurs when certain pollut­ ants are picked up by organisms and are not broken down or eliminated. Instead, they VOCABULARY climate change • global warming • monoculture • deforestation • invasive species • pollutant • ozone layer • smog • biological magnificatio ecological footprint HS-LS2-7: Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity. EP&Clb: Students should be developing ah understanding that the ecosystem services provided by natural systems are essential to human life and to the functioning of our economies and cultures. EP&CIVa: Students should be developing an understanding that the effects of human activities on natural systems are directly related to the quantities of resources consumed and to the quantity and characteristics of the resulting byproducts. Also: EP&Cla, EP&Clla, EP&Cllc Visual Analogy Ecological Footprint Your ecological footprint includes both land and water areas affected by all the resources you use and the waste that you create.