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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Slides prepared by Jay Withgott and Heidi Marcum Copyright © 2008.

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Presentation on theme: "Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Slides prepared by Jay Withgott and Heidi Marcum Copyright © 2008."— Presentation transcript:

1 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Slides prepared by Jay Withgott and Heidi Marcum Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Ch 16 Marine and Coastal Systems: Resources, Impacts, and Conservation Part 2: Environmental Issues the Search for Solutions

2 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings This lecture will help you understand: The marine environment Major marine ecosystems Human uses of marine resources Human impacts on the marine environment The state of ocean fisheries Marine protected areas and reserves

3 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Central Case: collapse of the cod fisheries No fish has more impact on human civilization than the Atlantic cod Eastern Canadians and U.S. fishermen have fished for cod for centuries Large ships and technology have destroyed the cod fishery Even protected stocks are not recovering -Prey may now be competing with, and eating, young cod

4 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Cod are groundfish They live or feed along the bottom -Halibut, pollock, flounder Cod eat small fish and invertebrates They grow to cm long and can live 20 years Inhabit cool waters on both sides of the Atlantic There are 24 stocks (populations) of cod

5 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Oceans cover most of the Earth’s surface The oceans influence global climate, team with biodiversity, facilitate transportation and commerce, and provide resources for us They cover 71% of Earth’s surface and contain 97% of Earth’s surface water Oceans influence the atmosphere, lithosphere, and biosphere

6 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The oceans contain more than water Ocean water is 96.5% water -Plus, ions of dissolved salts Evaporation removes pure water and leaves a higher concentration of salt Nutrients (nitrogen and phosphorus) Dissolved gas -Oxygen is added by plants, bacteria, and atmospheric diffusion

7 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Ocean water is vertically structured Temperature declines with depth Heavier (colder saltier) water sinks -Light (warmer and less salty) water remains near the surface Temperatures are more stable than land temperatures -Water’s high heat capacity -It takes much more heat to warm water than air Oceans regulate the earth’s climate -They absorb and release heat -Ocean’s surface circulation

8 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The ocean has several layers Surface zone -Warmed by sunlight and stirred by wind -Consistent water density Pycnocline = below the surface zone -Density increases rapidly with depth Deep Zone = below the pycnocline -Dense, sluggish water -Unaffected by winds, storms, sunlight, and temperature

9 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Ocean water flows horizontally in currents Currents = the ocean is composed of vast riverlike flows -Driven by density differences, heating and cooling, gravity, and wind -Influence global climate and El Niño and La Niña -Transport heat, nutrients, pollution, and the larvae of many marine species Some currents such as the Gulf Stream are rapid and powerful -The warm water moderates Europe’s climate

10 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The upper waters of the oceans flow in currents

11 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Surface winds and heating create vertical currents Upwelling = the vertical flow of cold, deep water towards the surface -High primary productivity and lucrative fisheries -Also occurs where strong winds blow away from, or parallel to, coastlines Downwellings = oxygen-rich water sinks where surface currents come together

12 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Seafloor topography can be rugged and complex The seafloor consists of… -Underwater volcanoes -Steep canyons -Mountain range -The planet’s longest range is under water -Mounds of debris -Trenches -Some flat areas

13 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Understanding underwater geography Maps show… -Bathymetry = the measurement of ocean depths -Topography = the physical geography or the shape and arrangement of landforms Continental shelves = gently sloping areas that underlie the shallow waters bordering continents Shelf-slope break = sudden drop off of the continental shelf Continental slope = connects the continental shelf to the ocean floor

14 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings A stylized bathymetric profile of the ocean

15 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Regions of ocean differ greatly Some zones support more life than others Photic zone = well-lighted top layer that supports high primary productivity Pelagic = habitats and ecosystems occurring between the ocean’s surface and floor Benthic = habitats and ecosystems occurring on the ocean floor

16 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Open ocean systems vary in biodiversity Microscopic phytoplankton constitute the base of the marine food chain in the pelagic zone -Algae, protists, and cyanobacteria These organisms feed zooplankton -Which then feeds fish, jellyfish, whales, etc. Predators at higher trophic levels include larger fish, sea turtles, sharks, and fish-eating birds

17 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Animals of the deep ocean Animals adapt to extreme water pressure and the absence of light -Scavenge carcasses or organic detritus -Some are predators, while others have mutualistic relationships with bacteria -Some species carry bacteria that produce light chemically by bioluminescence Hydrothermal vents support tubeworms, shrimp, and other chemosynthetic species om/watch?v=D69hGv CsWgA

18 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Kelp forests harbor many organisms Kelp = large, dense, brown algae growing from the floor of continental shelves Dense strands form kelp forests along temperate coasts Shelter and food for organisms Absorbs wave energy and protects shorelines from erosion Eaten by people Alginates serve as thickeners in cosmetics, paints, paper, and soaps

19 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

20 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Coral reefs are treasure troves of biodiversity Located in shallow subtropical and tropical waters Corals = tiny colonial marine organisms -Related to sea anemones and jellyfish -Remain attached to rock or existing reef and capture passing food with stinging tentacles -Derive nourishment from symbiotic algae, zooxanthallae

21 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Coral reefs consist of millions of corals Coral reef = a mass of calcium carbonate composed of the skeletons of corals -Consists of millions of densely packed individuals -Protect shorelines by absorbing waves -Innumerable invertebrates and fish species find food and shelter in reef nooks and crannies utube.com/wat ch?v=5d3qie3 jbHk

22 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Coral reefs are in worldwide decline Coral bleaching = occurs when zooxanthellae leave the coral -Coral lose their color and die, leaving white patches -From climate change, pollution, or unknown natural causes Nutrient pollution causes algal growth, which covers coral Divers damage reefs by using cyanide to capture fish Acidification of oceans deprives corals of necessary carbonate ions for their structural parts

23 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Deepwater coral reefs exist They thrive in waters outside the tropics -On ocean floor at depths of m ( ft) Occur in cold-water areas Little is known about these reefs Already, many have been badly damaged by trawling -Some reefs are now being protected

24 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Intertidal zones undergo constant change Intertidal (littoral) ecosystems = where the ocean meets the land -between the uppermost reach of the high tide and the lowest limit of the low tide Tides = periodic rising and falling of the ocean’s height due to the gravitational pull of the sun and moon -Intertidal organisms spend part of their time submerged in water and part of their time exposed to sun and wind

25 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings A typical intertidal zone

26 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Intertidal zones are a tough place to live But they have remarkable diversity -Rocky shorelines, crevices, pools of water (tide pools) -Anemones, mussels, barnacles, urchins, sea slugs, starfish, and crabs Temperature, salinity, and moisture change dramatically from high to low tide -Sandy intertidal zones have slightly less biodiversity

27 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Salt marshes occur widely Salt marsh = occur along coasts at temperate latitude -Tides wash over gently sloping, sandy, silty substrates -High primary productivity -Critical habitat for birds and commercial fish and shellfish species -Filter pollution -Stabilize shorelines against storm surges

28 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings People have changed and destroyed salt marshes People have altered or destroyed salt marshes for development -We lose key ecosystem service -Flooding worsens

29 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Mangrove forests line coasts In tropical and subtropical latitudes -Replace salt marshes along sandy coasts Mangroves = trees with unique roots -Curve upwards for oxygen -Curve downwards for support Nurseries for commercial fish and shellfish Nesting areas for birds Food, medicine, tools, construction materials

30 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Mangrove forests have been destroyed Development for residential, commercial, and recreational uses Shrimp farming Half the world’s mangrove forests are gone Once destroyed, coastal areas no longer -Slow runoff -Filter pollutants -Retain soil -Protect communities against storm surges We are protecting only 1% of remaining mangroves

31 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Estuaries: where fresh and salt water meet Estuaries = water bodies where rivers flow into the ocean -Wide fluctuations in salinity Critical habitat for shorebirds and shellfish Transitional zone for anadromous (spawn in freshwater, mature in salt water) fishes Affected by development, pollution, habitat alteration, and overfishing

32 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Oceans provide transportation routes Humans have interacted with oceans for thousands of years -Moving people and products over vast distances -Accelerated global reach of cultures Has substantial impact on the environment -Moves resources around the world -Ballast water transplants organisms, which may become invasive

33 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings We extract energy from oceans Crude oil and natural gas -Oil spills damage fisheries Methane hydrate = a potential energy source -Ice-like solid methane embedded in water crystals -A vast supply, but research needs to be done Renewable energy sources, such as waves, tides, heat

34 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings We extract minerals from oceans Minerals such as sand, gravel, sulfur, calcium carbonate, and silica Rich deposits of copper, zinc, silver, and gold Manganese nodules are scattered along the ocean’s floor -But, they are too hard to currently mine

35 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Marine pollution threatens resources Even into the mid-20th century, coastal U.S. cities dumped trash and untreated sewage along their shores Oil, plastic, chemicals, excess nutrients make their way from land into oceans Raw sewage and trash from cruise ships Abandoned fishing gear from fishing boats In 2006, 359,000 Ocean Conservancy volunteers from 66 nations picked up 3.2 million kg (7 million lbs.) of trash

36 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Nets and plastic debris endangers marine life Plastic items dumped into the sea harm or kill wildlife Plastic is non-biodegradable -Drifts for decades -Washes up on beaches -Wildlife eat it or get entangled and die Marine debris affects people -Equipment damage The 2006 Marine Debris Research, Prevention and Reduction Act

37 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Oil pollution comes from spills of all sizes Major oils spills (i.e., the Exxon Valdez) make headlines and cause serious environmental problems Most pollution comes from small sources -Boat leakage and runoff from land -Naturally occurring leaks from the seabed Oil spills coat and poison wildlife

38 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Oil pollution has decreased Governments have implemented more stringent regulations The U.S. Oil Pollution Act of Creates a $1 billion prevention and cleanup fund -Requires all ships have double hulls by 2015 Recently, oil spills have decreased -The oil industry resists such safeguards

39 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Toxic pollutants contaminate seafood Mercury contamination -From coal combustion and other sources -Bioaccumulates and biomagnifies -Dangerous to young children and pregnant or nursing mothers -Avoid eating swordfish, shark, and albacore tuna -Eat seafood low in mercury (catfish, salmon, canned light tuna) Avoid seafood from areas where health advisories have been issued

40 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Excess nutrients cause algal blooms Harmful algal blooms = nutrients increase populations of algae that produce powerful toxins Red tide = algal species produce reddish pigments that discolor water -Illness and death to wildlife and humans -Economic losses to fishing industries and beach tourism Reduce runoff and prevent consumption of affected organisms

41 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Emptying the oceans We are placing unprecedented pressure on marine resources -Half the world’s marine fish populations are fully exploited -25% of fish population are overexploited and heading to extinction Total fisheries catch leveled off after 1998, despite increased fishing effort -It is predicted that populations of all ocean species we fish for today will collapse by the year 2048

42 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The total global fisheries catch has increased

43 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings We have long overfished People began depleting sea life centuries ago Some species hunted to extinction: Steller’s sea cow, Atlantic gray whale, Caribbean monk seal Overharvesting of Chesapeake Bay oyster beds led to the collapse of its fishery, eutrophication, and hypoxia Decreased sea turtle populations causes overgrowth of sea grass and can cause sea grass wasting disease People never imagined that groundfish could be depleted -New approaches or technologies increased catch rates

44 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fishing has industrialized Factory fishing = highly industrialized, huge vessels use powerful technologies to capture fish in huge volumes -Even process and freeze their catches while at sea Driftnets for schools of herring, sardines, mackerel, sharks Longline fishing for tuna and swordfish Trawling for pelagic fish and groundfish

45 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fishing practices kill nontarget animals By-catch = the accidental capture of animals Driftnetting drowns dolphins, turtles, and seals -Fish die from air exposure on deck -Banned or restricted by many nations Longline fishing kills turtles, sharks, and albatrosses -300,000 seabirds die each year Bottom-trawling destroys communities -Likened to clear-cutting and strip mining

46 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Modern fishing fleets deplete marine life rapidly Grand Banks cod have been fished for centuries Catches more than doubled with immense industrial trawlers -Record-high catches lasted only 10 years

47 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Industrialized fishing depletes populations Catch rates drop precipitously with industrialized fishing -90% of large-bodied fish and sharks are eliminated within 10 years -Populations stabilize at 10% of their former levels Marine communities may have been very different before industrial fishing -Removing animals at higher trophic levels allows prey to proliferate and change communities

48 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Oceans today contain only one-tenth of the large-bodied animals they once did

49 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Several factors mask declines Industrialized fishing has depleted stocks, global catch has remained stable for the past 20 years -Fishing fleets travel longer distances to reach less- fished portions of the ocean -Fleets spend more time fishing and have been setting out more nets and lines, increasing effort to catch the same number of fish -Improved technologies: faster ships, sonar mapping, satellite navigation, thermal sensing, aerial spotting -Data supplied to international monitoring agencies may be false

50 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings We are “fishing down the food chain” Figures on total global catch do not relate the species, age, and size of fish harvested As fishing increases, the size and age of fish caught decline -10-year-old cod, once common, are now rare As species become too rare to fish, fleets target other species -Shifting from large, desirable species to smaller, less desirable ones -Entails catching species at lower trophic levels

51 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Consumer choices influence fishing practices Buy ecolabeled seafood -Dolphin-safe tuna Consumers don’t know how their seafood was caught -Nonprofit organizations have devised guides for consumers -Best choices: farmed catfish and caviar, sardines, Canadian snow crab -Avoid: Atlantic cod, wild-caught caviar, sharks, farmed salmon

52 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fisheries management Based on maximum sustained yield -Maximal harvest while keeping fish available for the future -Managers may limit the harvested or restrict gear used Despite management, stocks have plummeted -It is time to rethink fisheries management Ecosystem-based management -Shift away from species and toward the larger ecosystem -Consider the impacts of fishing on habitat and species interactions -Set aside areas of oceans free from human interference

53 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings We can protect areas in the ocean Marine protected areas (MPAs) = established along the coastlines of developed countries -Still allow fishing or other extractive activities Marine reserves = areas where fishing is prohibited -Leave ecosystems intact, without human interference -Improve fisheries, because young fish will disperse into surrounding areas Many commercial, recreation fishers, and businesses do not support reserves

54 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Reserves work for both fish and fisheries Found that reserves do work as win-win solutions Overall benefits included… -Boosting fish biomass -Boosting total catch -Increasing fish size Benefits inside reserve boundaries included… -Rapid and long-term increases in marine organisms -Decrease mortality and habitat destruction -Lessen the likelihood of extirpation of species

55 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Areas outside reserves also benefit Benefits included… -A “spillover effect” when individuals of protected species spread outside reserves -Larvae of species protected within reserves “seed the seas” outside reserves -Improved fishing and ecotourism

56 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings How should reserves be designed? 20-50% of the ocean should be protected in no-take reserves -How large? -How many? -Where? Involving fishers is crucial fisheries in coming with these answers

57 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Conclusion Oceans cover most of our planet and contain diverse topography and ecosystems We are learning about the oceans and coastal environments, intensifying our use their resources and causing severe impacts Setting aside protected areas of the ocean can serve to maintain natural systems and enhance fisheries We may once again attain the ecological systems that once flourished in our waters

58 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review An “upwelling” is defined as…. a)The vertical flow of cold, deep water towards the surface b)The vertical flow of warm, deep water towards the surface c)The vertical flow of cold, shallow water towards the bottom d)The vertical flow of warm, deep water towards the bottom

59 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review The area of an ocean that contains open water that receives sunlight is called the _______zone. a)Littoral b)Photic c)Pelagic d)Benthic

60 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review _____ is defined as “large, dense, brown algae growing from the floor of continental shelves.” a)Coral b)Red tide c)Bottomfish d)Kelp

61 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review Coral bleaching occurs when …. a)Corals reproduce b)Fish move into coral reefs c)Zooxanthellae leave the coral d)Coral reefs expand their range

62 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review An area where rivers flow into the ocean is called a(n) …? a)Estuary b)Mangrove swamp c)Salt marsh d)Coral reef

63 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review Which of the following does not mask the decline of fisheries? a)Fishing fleets travel longer distances b)Fishing fleets spend more time fishing c)Fishing fleets use traditional methods of fishing d)Data supplied to monitoring agencies may be false

64 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review Marine reserves have all the following benefits except: a)Fishing increases in the reserve b)The size of fish increases c)Larvae can “seed” areas outside the reserve d)Decreased mortality and habitat destruction

65 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Interpreting Graphs and Data What does this graph show about the future of global fisheries catch? a)China will be a major player in applying fishing pressure b)China will be player a smaller role in applying fishing pressure c)The world will decrease its fishing pressure d)The U.S. is not included in this graph

66 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Interpreting Graphs and Data Which conclusion can you draw from this graph? a)Oceans today contain far fewer fish b)Oceans today contain far more fish c)It is easier to find fish today d)There is little correlation between fishing and fish stocks

67 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Viewpoints If a developer wants to build a community on an estuary, providing jobs but eliminating the marsh, what should be done? a)Let the developer build; we need the jobs b)Let the developer build, but make him/her pay for any damage from storms c)Let the surrounding landowners vote whether to let the developer build d)Prevent the development; the potential damage is too great

68 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Viewpoints Do you plan to alter your decisions about eating seafood? a)Yes; I will be more selective about what I eat b)No; I will continue to eat the same type and amount of seafood as always


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