Human Impacts on Ecosystems (College Board AP® Environmental Science): Flashcards
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What can happen to organisms exposed to a pollutant outside their range of tolerance?
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What can happen to organisms exposed to a pollutant outside their range of tolerance?
Outside their range of tolerance, organisms may suffer physiological stress, limited growth, reduced reproduction, and in extreme cases death.
How do sediments and fertilizers in runoff damage coral reefs?
Sediments and fertilizers in runoff suffocate corals and promote algae growth.
True or False?
Coral bleaching is caused by rising ocean temperatures.
True.
Rising ocean temperatures cause corals to release the symbiotic algae that feed them, which can lead to reef death.
Ocean acidification lowers the pH of seawater, making it hard for corals to form skeletons.
Ocean acidification lowers the pH of seawater, making it hard for corals to form calcium carbonate skeletons.
Which destructive fishing practices damage coral reefs?
Destructive fishing practices include blast fishing, using cyanide to stun fish, bottom trawling, which breaks reef structures, and overfishing of key reef species.
How does oil coating the feathers of seabirds harm them?
Oiled birds may lose their buoyancy and ability to fly, and they ingest the oil when cleaning themselves, which can lead to death.
Why does an oil spill make sea otters vulnerable to hypothermia?
Oil disrupts the air insulation in sea otters' fur, so they cannot stay warm.
True or False?
Oil spills only harm the large animals that come into direct contact with the oil.
False.
Oil spills also harm primary producers such as phytoplankton, which disrupts the food web and affects larger predators.
How can an oil spill increase the risk of coastal erosion?
Oil settles in the root systems of mangroves and salt marshes and chokes the roots, killing the plants and increasing the risk of coastal erosion.
What are the positive economic impacts of an oil spill on the local economy?
Positive impacts include jobs during the cleanup, increased local revenue in shops, restaurants, and hotels, and financial aid such as grants, settlements, and disaster relief.
True or False?
The negative economic impacts of an oil spill are mainly short-term.
False.
The negative impacts are long-term, including lost tourist revenue, lost commercial fishing revenue, and lower coastal property values.
Which two industries did the 2010 Deepwater Horizon oil spill significantly damage?
The Deepwater Horizon spill significantly damaged the fishing and tourist industries of the Gulf of Mexico coast.
Define dead zone.
A dead zone is an area of water with very low or absent dissolved oxygen where no life can be found.
What is the main cause of oceanic dead zones?
The main cause is nutrient pollution (excess nitrogen and phosphorus) from agricultural runoff and sewage, which drives eutrophication.
True or False?
Oil spills contribute to dead zones by triggering algal blooms.
False.
Oil spills and dumped toxic chemicals contribute to dead-zone conditions through direct toxicity, not through algal blooms.
The Gulf of Mexico dead zone is largely caused by nutrient pollution from agricultural runoff in the River.
The Gulf of Mexico dead zone is largely caused by nutrient pollution from agricultural runoff in the Mississippi River.
Define oxygen sag curve.
An oxygen sag curve is a plot of dissolved oxygen levels against the distance from a point source of pollution.
True or False?
Warm water can hold more dissolved oxygen than cool water.
False.
The cooler the water, the more dissolved gases, such as oxygen, it can hold.
Define biochemical oxygen demand (BOD).
Biochemical oxygen demand is the amount of dissolved oxygen needed to break down the organic material in a given volume of water through aerobic biological activity.
Why is the sample in the 5-day BOD test incubated in the dark?
The sample is kept in the dark to prevent photosynthesis from adding oxygen back to the water.
How is BOD calculated from the 5-day BOD test?
BOD = DO₀ − DO₅, the initial dissolved oxygen minus the dissolved oxygen after 5 days of incubation at 20 °C.
Water that contains no dissolved oxygen at all is described as .
Water that contains no dissolved oxygen at all is described as anoxic.
Why do heavy metals pose a long-lasting threat to aquatic food chains?
Heavy metals do not degrade in the environment and build up in living tissue (bioaccumulation), disrupting the food chain.
Which heavy metal is liquid at room temperature and produces a toxic, odorless vapor?
Mercury (Hg) is liquid at room temperature and produces a toxic, odorless vapor.
How can swallowed litter harm aquatic animals?
Swallowed litter can cause internal damage, digestive tract blockage, and a false impression of fullness, leading to malnutrition and death.
True or False?
Plastics in water can absorb pollutants.
True.
Plastics absorb pollutants from the water and release harmful chemicals when animals ingest them.
How does sediment in waterways affect aquatic plants?
Sediment blocks sunlight from reaching aquatic plants, reducing photosynthesis and food availability in the ecosystem.
Fine sediment can block the of fish, reducing their ability to exchange oxygen.
Fine sediment can block the gills of fish, reducing their ability to exchange oxygen.
What do bacteria in water convert mercury into?
Bacteria convert mercury into highly toxic methylmercury, which accumulates in the bodies of fish.
True or False?
The concentration of methylmercury decreases as it passes up the food chain.
False.
Methylmercury concentration increases as larger fish eat smaller fish (biomagnification), so humans who eat large predatory fish such as tuna build it up.
What was the effect of the 1956 methylmercury release into Minamata Bay, Japan?
Local people who ate contaminated fish and shellfish suffered mercury poisoning, causing paralysis, death, or birth defects in newborns.
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