Ocean Pollution Unit II: Examples of Pollution (5 pts)

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1 Examples of Ocean Pollution Unit (Topic 13B-2) page 1 Name: Section: Ocean Pollution Unit II: Examples of Pollution (5 pts) In this unit, we will examine specific examples of ocean pollutants. DDT DDT is a pesticide that was commonly in use in the United States until the 1970s, by which time its dangers had been realized. It washed off crops, down rivers, and into the oceans where it bioaccumulated (e.g., passed up the food chain). In one famous example, the population of brown pelicans in southern California dropped rapidly when high DDT concentrations in their food caused their eggs to break: mother birds were sitting on and crushing their babies. DDT is a calcium inhibitor. It weakens the calcium carbonate in the egg shells. Another example: By the 1960s, DDT reduced nesting bald eagle population to 417 birds! They were finally taken off the endangered species list in In southern California, the Montrose plant in Torrance (and others) dumped their wastes into the local sewer system from the 1940s until the 1970s. Sewage pipes dumped DDT and other chemicals into the ocean south of Palos Verdes, and lots of them are still present in the local sediments. As a result, we have a large ocean superfund site in the United States, right here along our coastline. Superfund is the nickname for the law (CERCLA, 1980) that allows the Environmental Protection Agency (EPA) to identify and assess places with chemicals that are dangerous to human health and the local environment. The EPA has ranked how dangerous each place is, and prioritizes getting the most dangerous places cleaned up. According to the Superfund law, the EPA can force polluters to clean up their mess, but in some cases like Palos Verdes there is so much pollution that the original polluters cannot afford to clean it up: If the government tried to make them do so, then the polluters would immediately go out of the business, and the pollution would not get cleaned up. Thus, the government (i.e., our tax dollars) has to the clean up most of the mess one way or the other, and polluters if they are still in business have to contribute a reasonable amount. Government agencies and environmental groups try to warn fishermen and the public not too catch, sell, or eat certain kinds of fish, particularly those that eat worms and other animals that might have been living in toxic mud. They are also told to avoid eating fatty tissues, which are more likely to have the toxins in them. Recent measurements by the Environmental Protection Agency (2009) suggest that DDT and PCB levels have dropped by 90% in the sediments since the last sampling five years before, much faster than the 1-2% per year that had been measured previously. However, levels in ocean life have not gone down much at all. Where much of the DDT has gone and why is still unclear. Since only a few samples were taken (to keep down costs), perhaps they just happened to take samples in spots with low concentrations.

2 Examples of Ocean Pollution Unit (Topic 13B-2) page 2 Controversially, DDT is still used in some places to kill malaria-causing mosquitoes. Some people think widespread malaria is worse for public health than pollution-related illnesses and environmental damage. 1. A superfund site is a place that the Environmental Protection Agency has identified as one of the most contaminated areas in the United States. Where is the most highly polluted ocean superfund site in southern California? 2. What is the contaminant at the superfund site? 3. Who released the contaminant into the environment? 4. How did the contaminant get into the ocean? PCBs PCBs are a family of chemical compounds that are difficult to break down. This made them valuable in many products, particularly as insulators in electronics. Other products with PCBs included rubbers, paints, and oils (it makes oils less liking to burn!). PCBs durability makes them dangerous pollutants, because they break down into their harmless components very slowly. Unfortunately, PCBs potential for harming people was not realized until decades after their widespread use and the unrestricted dumping of products containing them. Known health problems among humans include liver damage and a painful and disfiguring skin disease. Perhaps the most interesting aspect of PCBs in the ocean is how widespread they are. Even though products were dumped primarily in developed countries, PCBs are a problem for many animals who live near the Poles, thus showing how effective the ocean s currents and the atmosphere s winds are at spreading out pollutants. For example, bioaccumulation of PCBs has caused female polar bears to develop male genitals. Studies of people who live in the Arctic and eat pilot whales have shown that PCBs appear to reduce the effectiveness of vaccines against illnesses like tetanus. 5. There is not much manufacturing and dumping of PCBS near the Poles, yet there are plenty PCBs found in the ocean there. How did the PCBs probably get there?

3 Examples of Ocean Pollution Unit (Topic 13B-2) page 3 Mercury Like DDT and PCBs, mercury becomes dangerous in the ocean via bioaccumulation: some bacteria use mercury for a process like chemosynthesis and in doing so make it more toxic. The bacteria are eaten by zooplankton, and the more they eat, the more toxic they become. Of course, fish then eat the zooplankton, and the more they eat, the more toxic they become. The bacteria also can release the mercury into the water where it can be absorbed by phytoplankton and other organisms. However, unlike DDT and PCBs, mercury is not a man-made substance, so we do not harm the environment by making mercury mercury is a natural substance but by releasing mercury in unnaturally large quantities into the environment. Mercury is used in several industries, and often released into the atmosphere via smokestacks that are burning coal. The mercury is then washed out of the atmosphere when it rains, where it gets into soil and the ocean. Mercury can cause neurological disorders: A few of the many possible effects include blindness, brain damage, and birth defects. Some people are unable to control their own bodies: they might shake uncontrollably or become paralyzed. An example of what the disorder might do to someone is the Mad Hatter from Alice in Wonderland whose character is based on real-life hatters who tended to become a little crazy from mercury-poisoning back in Victorian England. Hatters making felt hats worked too closely with mercury. We just didn t know any better back then. 6. How does mercury typically get into the bodies of fish and other ocean animals? 7. How did most of the mercury in the ocean get into the ocean? 8. What are the effects of mercury poisoning? How will it harm you?

4 Examples of Ocean Pollution Unit (Topic 13B-2) page 4 Eating Fish and Other Seafood: Some Recommendations Eating fish is an important part of a healthy diet. Most fish have omega-3 fatty acids (good for your heart) and are low in saturated fats, making them an excellent source of protein. However, to reduce the risk of mercury-related diseases (e.g., damage to hearing, hand-eye coordination, learning ability and more) in their children, pregnant women should probably avoid eating a lot of fish. Young children should have no more than 1/3 of a (solidly-packed) can of tuna per week, and women who may become pregnant should not eat more than 1 (solidly-packed) can per week. (You want to keep the levels in your body down if are thinking about having children anytime in the near future, say within the next couple of years. About 10% of women of childbearing age have mercury levels above those considered safe by the EPA.) Examples of seafood which typically have low levels of mercury include salmon, shrimp, clams, tilapia, crab, and scallops. (Eat up to 12 oz. a week. Fish sticks and fish sandwiches are made from lowmercury fish!) Albacore light tuna typically contains more mercury than light tuna. The FDA recommends avoiding large, predatory fish like shark, swordfish, tilefish, and king mackerel. In short: Eating organisms lower on the food chain is safer (less bioaccumulation, fewer toxins). According to a Food and Drug Administration study (FDA), human flesh is unfit for consumption, because the concentration of pollutants is too high (bad news for cannibals). Like other top predators, we get a large dose of pollutants in the foods we eat. 9. Who should be careful about how much fish they eat? 10. Is it probably healthier to eat larger fish or smaller fish?

5 Examples of Ocean Pollution Unit (Topic 13B-2) page 5 Plastics Plastics have been called a man-made miracle substance. Just think of all the items around you that are made out of plastic: pens, pencils, computer keyboards, combs, binders, car dashboards, cups, straws, action figures, and much, much more. Plastics are great because they can easily be molded into a wide variety of forms and are strong, durable, light-weight, and cheap to manufacture. Thus, you can make nearly anything out of them, the object will last, it will be easy to carry, and everyone can afford to buy what you make. These advantages are precisely what make plastics a dangerous ocean pollutant. (Some people consider plastic to be the worst ocean pollutant.) Since they are lightweight, plastics have a low density and thus float at the surface of the ocean where most ocean life is found. Plastics are strong and durable, so they do not break down easily or become soft. Many animals like seals, sea turtles, and sea gulls are strangled by or choke on plastics, presumably mistaking them for the transparent jellies that they normally eat. Their dead bodies contain stomachs full of plastic products, interfering with their ability to take in and digest their food. When the dead bodies decompose, the plastic is released back into the environment to kill again. Plastics do slowly break down over time, especially when exposed to sunlight, and become small particles. (Small plastic particles are making up a larger and larger part of our beach sediments!) However, plastics have a tendency to absorb toxic ocean pollutants including DDT and PCBs, so these tiny plastic particles may cause even more harm to ocean life through bioaccumulation than large plastic products do by choking animals. Tiny plastic particles are eaten by animals filter feeding plankton from the ocean: the more the animals eat, the more toxins build up in their bodies and in the bodies of predators who eat them. Plastic also takes up space in animals stomachs, so it interferes with their ability to take in and digest their food. Since plastic products are cheap to make, lots are made, lots are bought, and people don t worry about throwing them away, since it is cheap to buy more. Thus, a lot of plastics end up getting washed down storm drains and into the ocean, and organisms are more likely to encounter and eat them. About 1 in 6 plastic water bottles are recycled. In the next 10 years, people will throw away enough plastic water bottles to cover the entire coast of California 6-inches deep and 20- feet wide. Almost every bit of plastic that we have made still exists. (A very small amount has been incinerated.) Most plastic litters the land or ended up in landfills, but a large amount has also congregated in the center of the ocean gyres, pushed and held there by the prevailing surface winds and ocean currents. People who sail through these waters see plastics floating on the surface as far as the eye can see in every direction. In these places, the amount of plastic is 6 times heavier than the amount of plankton. In the North Pacific Ocean, plastic debris covers an area twice the size of Texas.

6 Examples of Ocean Pollution Unit (Topic 13B-2) page 6 Most ocean pollution is found near the coasts, because most pollution is washed off the land, including plastics. That being said, plastics are becoming a major exception to the rule that most pollution is found near the coasts. 11. How do large pieces of plastic harm ocean animals? 12. How do small pieces of plastic harm ocean animals? 13. Does plastic have a high density or a low density? Does it float or sink in ocean water? 14. How does the fact that plastic pollution floats make it an especially harmful ocean pollutant? 15. True or false? Most plastic pollution is found in the middle of the oceans, far from land. 16. True or false? Most ocean pollution is found close to land, not in the middle of the ocean.

7 Examples of Ocean Pollution Unit (Topic 13B-2) page 7 Oil When people are asked to think of an example of ocean pollution, often the first thing that they think of is an oil spill. Ironically, some scientists consider oil to be one of the least harmful ocean pollutants, because oil is a hydrocarbon: it is a fossil fuel, and thus was originally a carbohydrate in a living organism. (Carbohydrates have 1 water molecule per carbon atom. The oxygen atoms are removed to make it into a hydrocarbon. You can see how the word hydrocarbon is the word carbo-hydrate reversed.) In other words, oil is a natural substance that is biodegradable; for example, it is the source of energy for some chemosynthetic bacteria. Oil is an example of a natural substance that humans introduce into the environment in unnaturally high concentrations. It is the unnaturally high concentration that can make it a pollutant. Humans have only caused the amount of oil in the ocean to nearly double its natural level, mainly because of oil leaking from our cars and other machines that is washed into the ocean (not oil spills): The amount of oil washed off the land and into the ocean each year is equal to about 17 Exxon Valdez (a large tanker) oil spills. Oil, natural gas, tar, and other petroleum products naturally leak from the bottom of the ocean in many places including southern California and support chemosynthetic communities of organisms. (See topic 10B, Deep-Sea Life, for more information.) Most of the oil in the ocean (over 60%) has leaked naturally from the ocean bottom. Of course, oil spills do cause tremendous harm to ocean life. Lots of algae, animals, and plants quickly die after being coated with oil. Oil ruins the insulating feathers and fur of marine birds and mammals, so they become too cold and die. Some animals are poisoned by ingesting the oil. The toxic compounds mixed in with the oil often hit plankton the worst, killing both the plankton at base of the food chain and the eggs and larvae of large animals: an entire generation can be lost. However, most populations begin to rebound within a few years, and within years the environment will have pretty much recovered. The major exception is beaches; toxic oil remains among the sediments for many more years to come. Unlike the open ocean, waves and currents have great difficulty spreading out the pollution within the sediments of the beach (and thus making it less harmful). Humans have just as much difficulty cleaning up beaches after oil spills as nature does. Our best cleaning tools scalding-hot water from high pressure hoses and harsh chemical cleaners are very effective at cleaning the sediments, but they also kill the surviving algae and animals, essentially sterilizing the beach. In some cases, beaches that were not cleaned by humans have recovered faster than beaches that were cleaned! So, it is very important to keep oil spills from reaching the shoreline; doing so can save a vast amount of time and money on clean-up efforts and reduce the time for the environment to heal. In 1969, the death and destruction produced by the blowout of an oil platform near Santa Barbara helped inspire many of the first environmental organizations in the United States. The

8 Examples of Ocean Pollution Unit (Topic 13B-2) page 8 public reaction led to President Nixon signing the bill that founded the Environmental Protection Agency (EPA). For more information, see the link in the website section of the course website. To keep oil from reaching land, we use booms and skimmers. Booms are long, thin, floating barriers. Since oil floats, booms can block oil. However, waves can push oil over booms, and harsh winds and waves can sink them. We also skim oil off the surface: Typically, oil is collected using booms and then rotating plastic drums or discs are inserted into the oil. The oil sticks to the specially-designed or treated plastic and is brought onboard, scrapped off, and the drums or discs are reinserted to skim more oil. If weather conditions are right, the oil is simply lit on fire to burn it away. Dispersants can be added to the water to break up the oil, much as you use soap to get oils and grease off your dishes. This allows the oil to spread out into smaller toxic pieces that will do less damage to ocean life, and also allows the oil to sink deeper, away from the surface where most ocean life lives. However, these dispersants are also toxic to ocean life, and for this reason they are not introduced down deep where there are few waves and currents to spread them out, because they are more likely to stay concentrated and make the bottom sediments toxic. Controversially, the company BP added dispersants deep in the ocean to try to reduce the damage being caused by oil rising up from the ocean floor from the Deepwater Horizon oil spill (2010). The company argued that adding dispersants would keep concentrated oil from reaching the surface, and thus reduce damage to the life at the surface at the ocean. Their critics pointed out that it would also mean less oil at the surface for cameras to record, and that the oil and dispersants would remain down deep and cause damage for a much longer period of time than if they reached the surface but the damage would happen where few could see or record it. A fast response to an oil spill will greatly reduce its harmfulness and make it much cheaper to clean up. The lightest parts of oil evaporate away within a few days at most, leaving behind mousse: a thick mixture of oil, air, water, and anything in the ocean water. Skimming, burning, and dispersants are much less effective on mousse. This is why oil companies are suppose to have emergency plans and clean-up equipment nearby before they start drilling. 17. How did most of the oil in the ocean get into the ocean? 18. What is the major way in which humans contribute to the amount of oil in the ocean? 19. Is oil biodegradable? If so, what breaks it down? If not, why is it so hard to break down?

9 Examples of Ocean Pollution Unit (Topic 13B-2) page Why do many people consider oil to be one of the least dangerous ocean pollutants? 21. When there is an oil spill, what should the priority be: to keep the oil from reaching the coast or to keep the oil from drifting out into the ocean? Bioremediation One interesting method of cleaning up oil spills and other forms of pollution is bioremediation. Bioremediation is using living organisms to clean up pollution. For example, geneticallyengineered plants are being developed do soak up mercury from soil and lakes, keeping it from getting washed into the ocean. The plants can then be harvested and properly disposed of. In the case of oil, chemosynthetic bacteria that live off of oil can be introduced in the area of the oil spill. In principle, they will multiply quickly, decompose ( break down ) the oil, and then die off or go dormant when their task is done. Research on beaches in Scotland (it is near the North Sea where there are lots of oil rigs) have shown that beaches recover from a second oil spill faster than the first, presumably because of dormant bacteria that originally came to the beach after the first spill. When sand from a beach that had recovered from an oil spill was transplanted to a beach which had never endured an oil spill, researchers showed that it helped vaccinate the pristine beach against a future oil spill. As we have discussed before, if humans add or allow too many nutrients to enter the ocean, the nutrients can cause harmful algal blooms like red tides and dead zones. Wetland plants and algae are excellent at absorbing nutrients from rainwater runoff, reducing how many nutrients reach the rest of the ocean. Also, filter feeders (plankton-eaters) like oysters, mussels, clams, and other shellfish can eat very small plankton, including phytoplankton, preventing their numbers from becoming large enough to cause harmful algal blooms. Thus, two ways to prevent harmful red tides and dead zones are to restore wetlands along the coast and to create reefs of filter feeders like oysters in estuaries. 22. What is bioremediation? 23. Give a specific example of bioremediation.

10 Examples of Ocean Pollution Unit (Topic 13B-2) page 10 Sewage and Sewage Treatment In the movie Find Nemo, the characters repeat the line All drains lead to the ocean again and again. They are right, but there are two different systems which carry our water to the ocean: the sewer system and the storm drain system. The sewer system includes the pipes that are connected to the drains in your home: the kitchen sink, the bathroom sink, the toilet, the bathtub, the shower, the washing machine, etc. The used water from these drains goes to a sewage treatment plant where materials are separated out according to their density, broken down using chemicals and bacteria, and sterilized (e.g., using chlorine) to kill any remaining bacteria (which might cause illness). The resulting solid materials are rich in nutrients and often sold as compost, and some treated water is used by golf courses, parks, and others. The rest of the treated water and disinfected material is released into the ocean, typically miles from shore via long, underwater sewer pipes. Sewage treatment does not remove all chemicals from wastewater. For example, sucralose, the artificial sweetener in Splenda, goes through your body without being altered and is excreted. It then goes through wastewater treatments plants and is also not affected by the treatment process. When it rains, extra water goes down drains that are connected to the sewage system, and if the rainfall is heavy, water can start to back up in the sewage treatment plant. Sometimes the plant has to release untreated water into the ocean to avoid getting flooded! From a Sanitation District mailer sent to me: The Sanitation Districts clean you wastewater (sewage) and turn it into resources 24 hours a day, 7 days a week, 365 days a year. This is a complex process that ensures that pollutants are safely removed to protect public health and the environment. You are receiving this notice to inform you of a proposed rate increase and the public hearing scheduled for its consideration. We serve over 5.6 million people in 78 cities and unincorporated areas throughout Los Angeles County, treating 424 million gallons of wastewater per day in a way that is both environmentally sound and cost effective. That is enough water to fill the Rose Bowl five times every single day. Your city owns the local sewers that collect the sewage generated in your homes and businesses. From there, we transport your sewage to one of our 11 wastewater treatment plants, through a conveyance systems of 1,400 miles of large diameter sewers and 48 pumping plants. The sewage is then highly treated, producing recycled water that is suitable for a wide range of uses. Although our recycled water essentially meets drinking water standards, we don t directly drink it. Instead we use it to replenish our groundwater supplies. It s also used to irrigate parks, golf courses, schools, and other greenbelt areas, reducing the demand on our potable water supply (drinking water supply). By recycling water, we also lessen the need for importable water (water imported from other places).

11 Examples of Ocean Pollution Unit (Topic 13B-2) page 11 Most people do not like the idea of using treated water in their gardens or homes, but I am told that it is actually quite safe. If you think about it, the water we use is always treated. People living farther inland raw water from rivers and aquaducts for their needs, treat it, and dump it back into the rivers and aquaducts that then bring the water to us. We then treat (clean) the water before we use it in our home for drinking, cooking, cleaning, etc. Even if you are drinking bottled water, you are drinking water which has been drawn from rivers and aquaducts and treated by a private company (instead of a public utility). 24. How is the water coming out of sewage pipes treated before it is released into the ocean? What is in sewage water that we are trying to remove by treating the water? 25. How or why can untreated sewage cause a bloom of harmful algae? Storm Drains You can see storm drains everywhere along the sides of our streets. Since rain water cannot soak into the ground anymore (because we have paved over so much of the land of our cities), the job of storm drains is to get rain water off our streets as quickly as possible so that that water does not make driving dangerous or flood our homes and businesses. The rain water also picks up animal feces (from both pets and wild animals) and other materials (e.g., yard wastes like dead leaves and grass, oil drippings from cars, arsenic left behind by car tires, various heavy metals, fertilizers and pesticides from landscaped areas) which are washed directly into the ocean. In the past, these materials were typically filtered out of the runoff by forests and wetlands. Bacteria on the fecal material can cause beachgoers to get sick (liver, breathing, and stomach problems; ear and eye infections; hepatitis; paralysis). The ocean helps the bacteria get into our bodies through our eyes, ears, mouth, etc.: the water offers support to the bacteria so that they can drift to us. Note that it is bacteria from land animals that typically make human swimmers sick. Most ocean bacteria are not well adapted to invade that bodies of land mammals like humans. 85% of beach closures occur because of unacceptably high levels of fecal bacteria in the water. According to the EPA, if a beach has the maximum acceptable amount of bacteria (for the beach to stay open), about 2% of swimmers (1 in 50) will get sick. Local officials must wait a day or two for the results of water tests. During this time, beachgoers may be exposed to harmful bacteria and substances. Moreover, the surf zone is extremely turbulent, so by the time the test results are in, waves and currents may have moved significant amounts of pollutants to other beaches.

12 Examples of Ocean Pollution Unit (Topic 13B-2) page 12 Note that soaking into the ground is not necessarily a good thing anymore, because the water can pick up chemicals that can poison our water supply. In addition, groundwater in aquifers can move from the land into the ocean, so it is another route by which chemicals can enter the ocean. 26. What is the purpose of storm drains? What benefits do they provide to us? 27. What is the most harmful substance that is in storm drain water? Who is typically harmed by it, people who eat seafood or swim at the beach? What does the pollutant do to them? Coastal Development It is estimated that about 1,500 new homes are built along the coastline of the United States each day. Right now, more than 50% of our population lives in coastal counties (that cover 17% of the land in the lower 48 states), so that does not even count the population of the counties that are just a little bit inland like San Bernardino and Riverside. Coastal populations are increasing fast: they are expected to grow by over 30% between 2000 and As we pave over more land and more people generate more wastes than before, we can only expect more ocean pollution problems in the future. This is true throughout the world. You can tell that most people in the United States live close to the coast from the presidential election results in Trump got 46% of the vote and Clinton got 48% of the vote. (The Electoral College determined who won.) Thus, about half of the people voted for the Republican candidate and half voted for the Democratic candidate. If you look at the electoral maps, though, you will see that most of the country looks pretty red (Republican), except for the west coast and New England. Thus, even though red covers more than twice the area covered by blue, its population is not any larger; well over half our population has to be living near the coast. 28. True or false? Most people in the world live close to the coast, not inland.

13 Examples of Ocean Pollution Unit (Topic 13B-2) page 13 The Clean Water Act In the past, sewage did not have to be treated so extensively, so many coastal waters and estuaries near cities and industrial plants were heavily polluted. Since the Clean Water Act of 1972, sewage treatment plants have been required to improve the quality of the water that they release to a much higher standard, and sewage sludge nearly untreated solid materials rich in chemicals is no longer being dumped along the coasts of the United States. (In developing countries, some cities discharge untreated sewage directly into rivers and the ocean.) In addition to untreated sewage, farming can also add large amount of nutrients to the ocean. Farmers put lots of artificial fertilizers on their crops, helping them grow more food per acre. However, large amounts of these nutrients are washed off the fields and into rivers which carry them to the ocean. In addition, big-business agriculture involving industrial production of livestock (e.g., cattle, pigs, chickens) generates vast amounts of manure, which often gets washed into nearby lakes and streams when it rains. Note that while storm drain water does contain some nutrients from the land, the nutrients are not nearly as concentrated as they are in sewage and fertilizer runoff from farms. Thus, storm drain water does not typically cause harmful blooms of algae like red tides and dead zones. Harmful Blooms Offhand, you might expect that causing blooms is a good thing: more nutrients means more phytoplankton and thus ultimately more animals for us to eat. However, as we have dumped more and more nutrients into the ocean, we have found that they can also encourage the growth of harmful microorganisms. Some attack fish and other organisms directly, causing wounds (e.g., Pfisteria piscicida), or inhibiting feeding and/or breathing (produce lots of mucus, clog gills, e.g., species of Chaetoceros), but many harm other organisms and the environment by accident. 29. What must be present in a pollutant for it to cause a bloom of harmful algae? 30. What are the two major kinds of pollution that cause harm blooms of algae? 31. True or false? Storm drain runoff is a common cause of harmful blooms of algae.

14 Examples of Ocean Pollution Unit (Topic 13B-2) page 14 Red Tides: An example of a harmful bloom Red tides are a bloom of red-colored phytoplankton (typically dinoflagellates); there are so many phytoplankton in the water that they make the water look red (or brown or yellowish). Some red tide algae but not all! produce chemicals like domoic acid that are toxic to vertebrates like birds, mammals, and humans. Filter feeders Clam (or suspension feeders) like clams and other shellfish strain the algae out of the water during a bloom. They eat lots of algae, and the more they eat, the more toxic they become. (This is called bioaccumulation.) If we or other vertebrates (e.g., seals, sea gulls) eat the shellfish, we can become sick. Illnesses caused by toxins being passed up the food chain in this way include ciguatera fish poisoning (CFP), diarrhetic shellfish poisoning (DSP), and paralytic shellfish poisoning (PSP). In general, though, it is safe to swim in red tides; you won t swallow nearly enough water to become poisoned. However, the algae do leak toxins into the water, and these cause some people to develop rashes. As long as you get out of the water when you notice the rash and wash it off, you should be fine. Breaking waves can catapult these toxins into the air, and some of these toxins cause respiratory (breathing) problems for people who live near the coast. Note that the phytoplankton are not poisonous because of toxic chemicals absorbed from the water. Like many land plants, the phytoplankton naturally produce chemicals that are harmful to humans. The most dangerous organisms to eat are filter-feeders like clams, mussels, oysters and so on, because they are more likely to build up lots of toxins in their bodies (the toxins do not kill them). It should be safe to eat them in restaurants, because the United States has good regulations and does a good job of inspecting seafood. Restaurants will import shellfish if the local ones may be poisonous. 32. What are red tides? In other words, why does the water become red? 33. How can red tides harm humans? 34. How can red tides kill humans? 35. In general, is it safe to swim in a red tide? Why or why not? 36. In general, is it safe to eat in local restaurants during a toxic algae bloom? Why or why not?

15 Examples of Ocean Pollution Unit (Topic 13B-2) page 15 Dead Zones: An example of a harmful bloom Another example of a harmful algae bloom is a dead zone. At the end of the bloom (once the phytoplankton have used up all the nutrients), the water will be filled with a lot of dead phytoplankton. This encourages the growth of bacteria who decompose ( break down ) the bodies. In doing so, the bacteria use up the oxygen in the water. Animals that do not swim away (either because they cannot swim or because they cannot survive in the open ocean), die because they cannot breathe. One of the best known examples of a dead zone is the one that occurs at the end of the Mississippi River. The Mississippi drains practically the entire middle of the United States, including a vast amount of farmland. The fertilizers that the farmers put on their land to help them grow more food per acre and animal wastes from huge factory farms are washed off the land and into rivers. These rivers join with the Mississippi, which carries these nutrient-rich materials into the ocean. The resulting dead zone harms the livelihoods of the local fishermen. Harmful algae blooms cost the United States an estimated $100 million dollars each year in lost fisheries and tourism revenues. Dead zones were common in the Port of Los Angeles in the 1950s. The Clean Water Act limited the amount of nutrient pollution that could be dumped in the harbor, and since the mid- 1980s there have not been any more dead zones. Dead zones are most common where industries and cities add large amount of nutrients to the ocean (e.g., raising huge number of animals like cattle for food, intensive farming, dumping untreated sewage) Dead zones are more common than in the past, because more nutrients are entering the ocean than in the past. For example, the amount of nutrient nitrogen in the ocean increased by about 80% from 1860 to Scientists use the word eutrophication to describe the dead zone phenomenon, and the word anoxic ( no oxygen ) to describe the lack of oxygen in the water. 37. Why do animals die in an ocean dead zone? What do they die of? In other words, what kills them? 38. How or why can a bloom of phytoplankton create a dead zone? 39. What do humans add to the ocean that causes harmful blooms of algae? 40. How or why does this substance cause algae to bloom?

16 Examples of Ocean Pollution Unit (Topic 13B-2) page 16 More about Dead Zones Low oxygen conditions are usually worst on the bottom. Dead, decaying material sinks to the bottom, and the bacteria remove oxygen from the water as they decompose the dead bodies. In addition, in shallow coastal waters, the abundant phytoplankton near the surface block sunlight from reaching the bottom where macroalgae (seaweeds) live. The macroalgae die; instead of adding oxygen to the water near the bottom, their decomposing bodies help use up the remaining oxygen. If the density difference between the bottom water and surface is too high, waves and tidal currents will have difficulty bringing oxygen-rich surface water down to the bottom. Thus, global warming may be making dead zones worse: it keeps the warm surface water from mixing with cooler, deeper water. In addition, warm water cannot hold as much oxygen as cold water, so more oxygen is given to the atmosphere and less mixes downwards. This may be one of the reasons that dead zones are becoming larger and more common, and that oxygen levels below the surface are dropping in the Pacific Ocean. Why don t zooplankton eat the phytoplankton? Why do bacteria grow abundant and decompose the phytoplankton instead? Zooplankton (e.g., copepods) cannot eat all the new phytoplankton; there are simply too many. Phytoplankton and bacteria can reproduce much faster than zooplankton, so while the zooplankton population grows too, zooplankton cannot keep the phytoplankton from becoming dangerously overpopulated. One major example of the restoration of a dead zone demonstrates that it is best not to let the dead zone become large and widespread in the first place. With the collapse of communism (c. 1989), many eastern European economies collapsed as well, so fewer nutrients entered the Black Sea, and its dead zone became smaller. The recovery of ocean bottom has been very slow: the animals (e.g., fish) that once lived there did not simply bounce back when conditions became better. The new dominant species, jellies (an invasive species is one of the worst see the next section), eat plankton the fishes food and the fishes eggs and larvae, keeping fish populations from growing quickly or at all. Scientists call this a regime shift from a population of organisms that we like to eat to a population of organisms that we do not like to eat. Unfortunately, the new, jelly-dominated regime is quite stable: things are not going to change back to the way they were without a major disturbance. The future ocean may be a better place for jellies and worse place for fish. Warm water tends to have less oxygen than cold water: warm (fast-moving) water molecules form weaker bonds, so warm water cannot hold onto as many oxygen molecules as cold water can. Also, as the ocean absorbs our carbon dioxide pollution from burning fossil fuels (like oil and coal), it is becoming more acidic. Many species of jellies can tolerate low-oxygen water and acidic water, so they may grow more abundant in the ocean in the future and displace fish or other organisms in the food chain. Some biologists call these jellies dead end species, because many fish and other predators that we like to eat cannot live off the jellies. The fish population may be unable to

17 Examples of Ocean Pollution Unit (Topic 13B-2) page 17 bounce back even if we stop overfishing and polluting the ocean, because the jellies eat their fish eggs and larvae, keeping their populations down. Dead zones and red tides can occur naturally. Brief strong winds are becoming more common along the coast of Oregon. They produce brief, strong upwelling events followed by brief, massive blooms of phytoplankton. Since zooplankton cannot eat them all, many dead bodies sink deep into the ocean. Bacteria bloom as they decompose the bodies and in doing so use up all the oxygen in the deep waters, killing many of the animals who live there. Even unnaturally large blooms of good phytoplankton that do not result in dead zones can cause problems. Many ocean animals begin life as zooplankton that feed on phytoplankton. When then grow up, they become nekton or benthos that eat other things (e.g., seaweed, zooplankton, corals). If humans cause an unnaturally large bloom of phytoplankton, too many of these animals will survive into adulthood because they can grow quickly since they have abundant food when they are babies and they can disrupt their ecosystem by eating too much as adults. For example, they might eat an entire kelp forest or coral reef before their own predators can reduce their population to their original and stable level. 41. Where are the low oxygen conditions worst, near the surface or near the bottom? 42. Under which conditions is a dead zone most likely to occur, if the water is warm, if the water is cold, or if a layer of warm water is floating on top of a layer of cold water? 43. Why might there be more jellyfish and fewer fish in the oceans of the future? 44. Why might the fish population fail to grow back and replace jellies even if we stop polluting the ocean? 45. True or false? Harmful blooms like red tides and dead zone are caused by humans. In other words, harmful blooms do not occur naturally, so humans are always responsible.

18 Examples of Ocean Pollution Unit (Topic 13B-2) page 18 Invasive Species Invasive species are non-native species. They are animals, algae, bacteria, etc. that have been introduced to new place. Invasive species are also known as alien or exotic species. Invasive species are not really an example of pollution, but are an example of how human actions and negligence can harm an ocean environment. If you think about it, there are 3 things that can happen when a foreign species is introduced into a new environment: It will die out: it is quickly eaten (it is an exotic snack for the locals), cannot find food (nothing looks appetizing), have no one to reproduce with (nobody s here but us guys), etc. It will be able to survive and become a new member of the environment. It will be better than the native species (e.g., at finding food, won t have any predators) Almost all introduced species will die out, but a few will fall into the last category; its advantages will allow it to take over the environment where it was introduced, and the native species begin to die out. Invasive species can arrive in a new place on their own, but nowadays humans are carrying more and more with them as we quickly and easily travel the globe. Sometimes we even introduce new species intentionally, thinking that we will make a place better. So many foreign species have been introduced to San Francisco Bay, intentionally and unintentionally, that it almost entirely contains foreign species; we don t even know what it was originally ( naturally ) like. There are many examples of aquatic invasive species, but I will only discuss three. Toxic dinoflagellates (a kind of phytoplankton, some of which cause red tides) have been transported from estuary to estuary, presumably by ballast water (see below), and have poisoned the food chain in their new homes via bioaccumulation. Probably the most famous example of an aquatic invasive species is zebra mussels, a kind of mollusk (clam-like animal) that grows on hard surfaces like rocks. The zebra mussel was introduced to the Great Lakes from Europe in the 1980s, and spread quickly since it has no natural predators. It has killed native species by growing over them, taking the space where they want to live, or eating lots of plankton, causing native species to starve. In addition, they grow everywhere, clogging all kinds of pipes (e.g., storm drains, sewer pipes, power plant inflow and outflow pipes). The United States spends over $100 million per year scrapping them off, a breathtaking amount and waste of money. In southern California we have our own invader: caulerpa taxifolia, a fast-growing tropical seaweed that has caused havoc in the Mediterranean Sea already. Caulerpa taxifolia pushes aside native algae, and local animals do not eat it, so it just spreads and spreads. It is a popular decoration in aquariums, and it is thought that it was introduced along our coast when someone dumped their aquarium in the ocean. Caulerpa taxifolia was found in San Diego and Orange

19 Examples of Ocean Pollution Unit (Topic 13B-2) page 19 County in 2000, but fortunately, our (expensive) efforts to get it under control appear to be succeeding, thus preserving the food supply for native species. Marine invasive species are most commonly carried from place to place in the ballast water of cargo ships. Ballast water is water that is pumped into a ship from the ocean when a ship is not fully loaded. The water weighs the ship down so that it does not tilt when one end or side of the ship is unload, it does not rock back and forth too much, it is at the right height to be unloaded by cranes on land, and its propeller and rudder are at the right depth for maneuvering. The problem is that the ballast water may contain lots of plankton, and if they survive the trip, they may be pumped out into a foreign estuary, and take over. Scientists have worked on a number of systems to kill animals in ballast water (the main concern with this solution is that the poison will get released out into estuaries with the ballast water, and poison native animals and our food supply). A simple solution is to require ships to dump their ballast water in the middle of the ocean and take on new ballast water out there as well. Unfortunately, this costs time and money (fuel to get the huge cargo ship going and to bring it to a stop), so most ship owners are unwilling to do it. Local communities like our own have no right to make them do so, because only the federal government can Ballast Water make rules about interstate and international commerce. In 2004, the George W. Bush administration finally abandoned its use of voluntary guidelines (only about 30% of ships were complying) and instituted mandatory regulations with fines ranging up to $27, What are invasive species? 47. How are marine invasive species typically transported from one estuary to another estuary by humans? 48. Give several examples of how an invasive species could disrupt an ecosystem. For example, how could an invasive species harm the native inhabitants of an ecosystem?

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