Chapter 6Chapter 6Aquatic BiodiversityAquatic Biodiversity

AP Environmental ScienceAP Environmental Science

Edinburg North High SchoolEdinburg North High School

Chapter 6: Aquatic BiodiversityChapter 6: Aquatic Biodiversity

Focus Questions:• What are the basic types of aquatic life zones,

and what factors influence the kinds of life they contain?

• What are the major types of saltwater life zones, and how do human activities affect them?

• What are the major types of freshwater life zones, and how do human activities affect them?

Core Case Study:Core Case Study:

Why Should We Care about Coral Reefs?Why Should We Care about Coral Reefs?

• Coral reefsCoral reefs– Warm coastal watersWarm coastal waters– Marine equivalents of tropical rainforest (Marine equivalents of tropical rainforest (Fig. 6-1a))– Polyps (jellyfish relative), CaCOPolyps (jellyfish relative), CaCO33, symbiotic zooxanthellae, symbiotic zooxanthellae– 0.1% of world’s ocean area0.1% of world’s ocean area

• Ecological and economic servicesEcological and economic services– Moderate atmospheric temperatureModerate atmospheric temperature– Natural barriers protective 15% of world’s coastlineNatural barriers protective 15% of world’s coastline– Provides habitats for marine organismsProvides habitats for marine organisms– Produce one-tenth of global fish catchProduce one-tenth of global fish catch– Building materials for poor countriesBuilding materials for poor countries– EcotourismEcotourism

• ConservationConservation– 20% of the world’s coral reefs lost to coastal 20% of the world’s coral reefs lost to coastal

development, pollution, overfishing, warmer development, pollution, overfishing, warmer oceans, and other stressesoceans, and other stresses

– Another 30% will be lost in next 20-40 yrAnother 30% will be lost in next 20-40 yr– Coral bleaching, linked to warmer water and Coral bleaching, linked to warmer water and

silt from land (silt from land (Fig. 6-1b))

I. Aquatic EnvironmentsI. Aquatic Environments

• The Water Planet: Saltwater and FreshwaterThe Water Planet: Saltwater and Freshwater– Oceans cover 71% earth’s surface, freshwaterOceans cover 71% earth’s surface, freshwater

< 1% (< 1% (Fig. 6-2)– Major types of organisms determined by Major types of organisms determined by salinitysalinity..– Aquatic life zones classified into two major types:Aquatic life zones classified into two major types:

• MarineMarine, or , or saltwatersaltwater, includes estuaries, coastlines, coral reefs, , includes estuaries, coastlines, coral reefs, coastal marshes, mangrove swamps, and oceans.coastal marshes, mangrove swamps, and oceans.

• FreshwaterFreshwater, includes lakes, ponds, streams, rivers, and inland , includes lakes, ponds, streams, rivers, and inland wetlands.wetlands.

– Distribution of the worlds major saltwater oceans, coral Distribution of the worlds major saltwater oceans, coral reefs, mangroves and freshwater lakes and riversreefs, mangroves and freshwater lakes and rivers((Fig. 6-3)

– Play vital roles in ecosystems and human Play vital roles in ecosystems and human systemssystems• Biological productivityBiological productivity• ClimateClimate• Biogeochemical cyclesBiogeochemical cycles• BiodiversityBiodiversity• Fisheries: fish and shellfishFisheries: fish and shellfish• Oil, natural gas, and mineralsOil, natural gas, and minerals• Recreation and transport routesRecreation and transport routes

• What kinds of organisms live in aquatic life What kinds of organisms live in aquatic life zones?zones?– PlanktonPlankton

• PhytoplanktonPhytoplankton• ZooplanktonZooplankton• UltraplanktonUltraplankton

– NektonNekton– BenthosBenthos– DecomposersDecomposers

• Life in LayersLife in Layers– Three main layers: surface, middle, and bottomThree main layers: surface, middle, and bottom– Factors that determine the distribution and Factors that determine the distribution and

abundance of organisms:abundance of organisms:• Temperature, light, DO, nutrientsTemperature, light, DO, nutrients

– Photosynthesis confined to upper layer, or Photosynthesis confined to upper layer, or euphotic zoneeuphotic zone..• Depth depends on water clarity.Depth depends on water clarity.

– Nutrients (nitrates, phosphates, iron, and others) Nutrients (nitrates, phosphates, iron, and others) more limited in open ocean.more limited in open ocean.• Upwellings (see Suppl. 10) however has high NPP.Upwellings (see Suppl. 10) however has high NPP.

– Most deep bottom organism depend on dead Most deep bottom organism depend on dead debris that falls to the bottom.debris that falls to the bottom.

II. Saltwater Life ZonesII. Saltwater Life Zones

• Why should we care about the oceans?Why should we care about the oceans?– They provide many important ecological and They provide many important ecological and

economic services (economic services (Fig. 6-4).– We know less about the oceans and We know less about the oceans and

freshwater systems than we do about the freshwater systems than we do about the surface of the moon.surface of the moon.• Further study could yield immense ecological and

economic benefits.

• The Coastal Zone: Where Most of theThe Coastal Zone: Where Most of theAction isAction is– Two major life zones: coastal and open ocean (Two major life zones: coastal and open ocean (

Fig. 6-5).– Extends from high tide mark to end of Extends from high tide mark to end of continental continental

shelfshelf..• Relatively shallow, nutrient-richRelatively shallow, nutrient-rich• Numerous interaction with land, so easily affected by Numerous interaction with land, so easily affected by

human activities.human activities.

– Only 10% of the world’s ocean area, but contains Only 10% of the world’s ocean area, but contains 90% of marine species90% of marine species

– Site of most large commercial fisheriesSite of most large commercial fisheries– High NPP because of ample nutrients and High NPP because of ample nutrients and

sunlight.sunlight.

• Estuaries and Coastal Wetlands: Centers of Estuaries and Coastal Wetlands: Centers of ProductivityProductivity– EstuaryEstuary – area where rivers meet the sea – area where rivers meet the sea

• Seawater mixes with freshwater along with nutrients Seawater mixes with freshwater along with nutrients and pollutants (and pollutants (Fig. 6-6)

– Coastal wetlandsCoastal wetlands – coastal land areas covered – coastal land areas covered with water all or part of the yearwith water all or part of the year• River mouths, inlets, bays, sounds, and salt marshes (River mouths, inlets, bays, sounds, and salt marshes (

Fig. 6-7; in temperate areas) and mangrove forests in tropical zones (in tropical areas).

• Significant daily and seasonal changes in tidal and Significant daily and seasonal changes in tidal and river flows, and land runoff of sediment and other river flows, and land runoff of sediment and other pollutantspollutants

– Estuaries and coastal wetlands very productiveEstuaries and coastal wetlands very productive

– Mangrove forests are the tropical equivalents of Mangrove forests are the tropical equivalents of salt marshes.salt marshes.• 70 % of gently sloping sandy and silty coastlines in 70 % of gently sloping sandy and silty coastlines in

tropical and subtropical regions.tropical and subtropical regions.• Mangrove trees can grow in saltwater (Mangrove trees can grow in saltwater (Fig. 6-8).).• Systems provide important ecological and economic Systems provide important ecological and economic

servicesservices– Filter toxic pollutants, excess nutrients, and sediments.Filter toxic pollutants, excess nutrients, and sediments.– Reduce storm damageReduce storm damage– Provide food, habitats, and nursery sitesProvide food, habitats, and nursery sites– Intact mangroves worth $200,000-$900,000/kmIntact mangroves worth $200,000-$900,000/km22

• Based on sustainable fishing and fuel wood use; does Based on sustainable fishing and fuel wood use; does not include ecological services.not include ecological services.

• 10-45x more worth than when cleared for aquaculture10-45x more worth than when cleared for aquaculture• Protecting mangrove forest cost only $1000/kmProtecting mangrove forest cost only $1000/km22

• More than a third of the world’s have been destroyed.– For shrimp farms, crops, and coastal development– Bangladesh and the Philippines have lost almost ¾

• Rocky and Sandy Shores: Living with the Rocky and Sandy Shores: Living with the TidesTides– Gravitational pull from the sun and the moon Gravitational pull from the sun and the moon

causes tides to rise and fall every 6 hours causes tides to rise and fall every 6 hours (depending).(depending).

– Intertidal zoneIntertidal zone – area of the shoreline – area of the shoreline between low and high tides.between low and high tides.

– For an organism, lots of physical and For an organism, lots of physical and physiological stress.physiological stress.• Crashing wavesCrashing waves• High and low tides – periodic immersion and High and low tides – periodic immersion and

emersionemersion• Changing levels of salinityChanging levels of salinity

– Rocky shoresRocky shores ( (Fig 6-9a))• Are pounded by wavesAre pounded by waves• Numerous pools and other niches in the intertidal Numerous pools and other niches in the intertidal

zonezone• Remarkable number of niches in response to daily Remarkable number of niches in response to daily

and seasonal changes inand seasonal changes in– TemperatureTemperature– Water flowWater flow– Salinity Salinity

– Barrier beachesBarrier beaches, or , or Sandy ShoresSandy Shores ( (Fig. 6-9b))• Gently sloping shoresGently sloping shores• Many critters burrow into the sandMany critters burrow into the sand• Variety of shorebirds with specialized feeding niches Variety of shorebirds with specialized feeding niches

(Fig. 4-8)(Fig. 4-8)

– Barrier IslandsBarrier Islands ( (Fig. 6-10) • Low, narrow, sandy islands that form offshore from Low, narrow, sandy islands that form offshore from

a coastline.a coastline.• Prime targets for developmentPrime targets for development

– Examples: Atlantic City, NJ; Palm Beach, FL; South Examples: Atlantic City, NJ; Palm Beach, FL; South Padre Island, TXPadre Island, TX

– Development prone to destruction from mother natureDevelopment prone to destruction from mother nature• Flooding, beach erosion, and hurricanesFlooding, beach erosion, and hurricanes

– According to climate models many of the world’s barrier According to climate models many of the world’s barrier islands may be under water by end of century.islands may be under water by end of century.

• Undisturbed barrier islandsUndisturbed barrier islands– One or more rows of sand dunesOne or more rows of sand dunes– Dunes act as a line of defense against storm surgesDunes act as a line of defense against storm surges– Development disrupts these natural barrier island Development disrupts these natural barrier island

formationsformations• ““People inaccurately call these human-influenced People inaccurately call these human-influenced

events ‘natural disasters’.”events ‘natural disasters’.”

• Threats to Coral Reefs: Increasing StressesThreats to Coral Reefs: Increasing Stresses– Coral reefs found in clear,warm tropical and Coral reefs found in clear,warm tropical and

subtropical waterssubtropical waters• Thrive in clear, warm, fairly shallow water of constant Thrive in clear, warm, fairly shallow water of constant

salinity.salinity.• Temperature range (18Temperature range (18––30 30 ooC); bleaching can be C); bleaching can be

triggered with an increase of just one degree.triggered with an increase of just one degree.

– One-fourth of all marine species (One-fourth of all marine species (Fig. 6-11))• Biodiversity can be reduced by:Biodiversity can be reduced by:

– Severe stormsSevere storms– Freshwater floodsFreshwater floods– Invasion of predatory fishInvasion of predatory fish– Human activities (Fig. 6-12)Human activities (Fig. 6-12)

– Loss of Coral ReefsLoss of Coral Reefs• 20% are so damaged that they are unlikely to 20% are so damaged that they are unlikely to

recoverrecover• By 2050, 30-50% could be lost due to climate By 2050, 30-50% could be lost due to climate

change, habitat loss, pollution, and overfishingchange, habitat loss, pollution, and overfishing• Only 300 of 6000 reefs are protected (at least on Only 300 of 6000 reefs are protected (at least on

paper)paper)

– Ecology and EconomyEcology and Economy• Worth an estimated $100,000-$600,000 kmWorth an estimated $100,000-$600,000 km-2 -2 yy-1 -1 from from

small-scale sustainable fishing, tourism, and pet small-scale sustainable fishing, tourism, and pet trade.trade.

– Does not include ecological servicesDoes not include ecological services– If included, much cheaper to protect than to use them If included, much cheaper to protect than to use them

unsustainablyunsustainably

– There is evidence that coral reefs can recover.There is evidence that coral reefs can recover.• protection by restricted fishingprotection by restricted fishing• reducing inputs of nutrients and other pollutantsreducing inputs of nutrients and other pollutants

• Biological Zone in the Open Ocean: Light Biological Zone in the Open Ocean: Light RulesRules– Open sea – at edge of continental shelf.Open sea – at edge of continental shelf.– Divided into three vertical zones depending on Divided into three vertical zones depending on

light availability (Fig. 6-5)light availability (Fig. 6-5)– Euphotic zoneEuphotic zone – brightly lit upper zone – brightly lit upper zone

• Phytoplankton carry out photosynthesisPhytoplankton carry out photosynthesis• Nutrients low except at upwellingsNutrients low except at upwellings• DO highDO high• Populated with fast-swimming predatory fishPopulated with fast-swimming predatory fish

– Bathyal zoneBathyal zone – dimly lit middle zone – dimly lit middle zone• No photosynthesizersNo photosynthesizers• Zooplankton and smaller fishZooplankton and smaller fish

– Migrate to surface to feed at night.Migrate to surface to feed at night.

– Abyssal zoneAbyssal zone – lowest zone, dark and very – lowest zone, dark and very cold, and has little DOcold, and has little DO• Contains enough nutrients to support a large Contains enough nutrients to support a large

number of speciesnumber of species• Ocean floor is complexOcean floor is complex

– Mid-Atlantic RidgeMid-Atlantic Ridge– CanyonsCanyons– Trenches deeper than the height of Mt. EverestTrenches deeper than the height of Mt. Everest

• Food rains from above, called Food rains from above, called marine snowmarine snow– Deposit feedersDeposit feeders– Filter feedersFilter feeders

– Average productivity and NPP per unit area is Average productivity and NPP per unit area is low except at equatorial upwellingslow except at equatorial upwellings• Absolute productivity is large because ocean Absolute productivity is large because ocean

covers large area.covers large area.• Productivity increase as latitude increases.Productivity increase as latitude increases.

• Effect of Human Activities on Marine Effect of Human Activities on Marine Systems: Red AlertSystems: Red Alert– Humans have an affinity for the coastHumans have an affinity for the coast– Ecological and economic services being Ecological and economic services being

degraded or destroyed (Fig. 6-13)degraded or destroyed (Fig. 6-13)– In 2006, 45% of world’s pop. and more than In 2006, 45% of world’s pop. and more than

half in the US lived near the coasthalf in the US lived near the coast– By 2010, 80% projected to live near the coastBy 2010, 80% projected to live near the coast

III. Freshwater Life ZonesIII. Freshwater Life Zones

• Freshwater SystemsFreshwater Systems– 1% of earth’s surface1% of earth’s surface– LenticLentic, or standing: lakes, ponds, and inland , or standing: lakes, ponds, and inland

wetlands.wetlands.– LoticLotic, or flowing: streams and rivers, or flowing: streams and rivers– Ecological and economic services (Fig. 6-14)Ecological and economic services (Fig. 6-14)

• Lakes: Water-Filled DepressionsLakes: Water-Filled Depressions– Large natural standing bodies of standing Large natural standing bodies of standing

freshwater formed from precipitation, runoff, and freshwater formed from precipitation, runoff, and groundwater seepage.groundwater seepage.• Causes of depressions:Causes of depressions:

– Glaciation, crustal displacement, and volcanic activityGlaciation, crustal displacement, and volcanic activity

– Water supplied by rainfall, melting snow, and Water supplied by rainfall, melting snow, and streamsstreams

– Vary tremendously in size, shape and nutrient Vary tremendously in size, shape and nutrient availabilityavailability

– Four distinct zones defined by depth and Four distinct zones defined by depth and distance from shore (Fig.6-15)distance from shore (Fig.6-15)• Littorral zoneLittorral zone

– Shallow, near shore to depth rooted plants cannot growShallow, near shore to depth rooted plants cannot grow– Most productive zoneMost productive zone– Biodiversity high: algae, rooted plants, turtles, frogs, Biodiversity high: algae, rooted plants, turtles, frogs,

crayfish, bass, perch, carpcrayfish, bass, perch, carp

• Limnetic zoneLimnetic zone– Open sunlit layer away from shoreOpen sunlit layer away from shore– Main photosynthetic body of the lakeMain photosynthetic body of the lake– Primary organism: phyo- and zooplanktonPrimary organism: phyo- and zooplankton– Large fish inhabit this zone, move into littoral zone to feed Large fish inhabit this zone, move into littoral zone to feed

and reproduceand reproduce

• Profundal zoneProfundal zone– Open water where it is too dark for photosynthesisOpen water where it is too dark for photosynthesis– Fish adapted to lakes cooler, darker and lower oxygen Fish adapted to lakes cooler, darker and lower oxygen

levelslevels

• Benthic zoneBenthic zone– Bottom of the lakeBottom of the lake– Decomposers, detritus feeders, and fish that move from one Decomposers, detritus feeders, and fish that move from one

zone to another.zone to another.– Nourished from limnetic and littoral, and sediments that Nourished from limnetic and littoral, and sediments that

wash inwash in

– Thermoclines form in winter ad summer, but mix Thermoclines form in winter ad summer, but mix in the fall and spring.in the fall and spring.• These These overturnsoverturns mix the water equalizing mix the water equalizing

temperature, taking oxygen to the bottom, and temperature, taking oxygen to the bottom, and nutrients to the top.nutrients to the top.

• Effects of Plant Nutrients on Lakes: Too Much of a Effects of Plant Nutrients on Lakes: Too Much of a Good ThingGood Thing– Lake classified according to their nutrient content and Lake classified according to their nutrient content and

primary productivity.primary productivity.• OligotrophicOligotrophic – poorly nourished (Fig. 6-16a) – poorly nourished (Fig. 6-16a)

– Newly formed, deep, steep banksNewly formed, deep, steep banks

– Low NPP Low NPP clear water clear water

– Small populations of phytoplankton and fish (e.g., smallmouth bass Small populations of phytoplankton and fish (e.g., smallmouth bass and trout)and trout)

• EutrophicEutrophic – well-nourished (Fig. 6-16b) – well-nourished (Fig. 6-16b)– Excessive phosphates and nitrates Excessive phosphates and nitrates high NPP high NPP

– Sediments, organic material, and inorganic nutrients have washed Sediments, organic material, and inorganic nutrients have washed inin

– Plant growth and decompositionPlant growth and decomposition

– Typically shallow, murky brown or green w/ poor visibilityTypically shallow, murky brown or green w/ poor visibility

• Cultural eutrophicationCultural eutrophication• Many lakes are Many lakes are mesotrophicmesotrophic

• Freshwater Streams and Rivers: From Freshwater Streams and Rivers: From Mountains to the OceansMountains to the Oceans– Surface water – precipitation that does not Surface water – precipitation that does not

sink into the ground or evaporate.sink into the ground or evaporate.– Runoff – surface water that flows into streamsRunoff – surface water that flows into streams– Watershed, or drainage basin – land area that Watershed, or drainage basin – land area that

delivers runoff, sediment, and dissolved delivers runoff, sediment, and dissolved substances into a stream.substances into a stream.

– Most streams begin in elevated areas (e.g., Most streams begin in elevated areas (e.g., mountains, hills)mountains, hills)

– Flow from a mountain can be divided in to three different Flow from a mountain can be divided in to three different life zones (Fig. 6-17):life zones (Fig. 6-17):

• Source zone (or headwaters)Source zone (or headwaters)– Usu. Shallow, cold, clear, and swiftly moving Usu. Shallow, cold, clear, and swiftly moving high O high O22

– Low production Low production lack of nutrients and phytoplankton lack of nutrients and phytoplankton

– Nutrients mostly from once living material (leaves, branches, Nutrients mostly from once living material (leaves, branches, insects)insects)

– Plants, algae and mosses that attach to rockPlants, algae and mosses that attach to rock

– Fish and other animals have compact or flattened bodies to live Fish and other animals have compact or flattened bodies to live under stonesunder stones

• Others with streamlined, muscular bodies to swim in strong Others with streamlined, muscular bodies to swim in strong currents.currents.

• Transition zoneTransition zone– Merging of headwaters forming wider, deeper, and warmer streamsMerging of headwaters forming wider, deeper, and warmer streams

– Gentler slopes with fewer obstaclesGentler slopes with fewer obstacles

– Higher turbidity, slower moving, less oxygenHigher turbidity, slower moving, less oxygen

– More phytoplankton, and cool and warm-water fishes with less More phytoplankton, and cool and warm-water fishes with less oxygen requirements.oxygen requirements.

• Flood plain zoneFlood plain zone– Streams join into wider, deeper rivers that flow across broad, Streams join into wider, deeper rivers that flow across broad,

flat valleysflat valleys– Water usu. w/ higher temp and less DOWater usu. w/ higher temp and less DO– Support large populations of producers: algae, Support large populations of producers: algae,

cyanobacteria, and rooted aquatics along the shorecyanobacteria, and rooted aquatics along the shore– Muddy and contains high concentration so suspended siltMuddy and contains high concentration so suspended silt– Main channels support distinctive varieties of fish (e.g., carp Main channels support distinctive varieties of fish (e.g., carp

and catfish)and catfish)– Backwaters support species similar to lakesBackwaters support species similar to lakes– Mouth of river may be divided in to many channels as is Mouth of river may be divided in to many channels as is

flows through the deltaflows through the delta• Sediments deposit here and in the coastal wetlands and Sediments deposit here and in the coastal wetlands and

estuaries.estuaries.

– Coastal deltas, wetlands and inland floodplains Coastal deltas, wetlands and inland floodplains are important parts of earth’s natural capital.are important parts of earth’s natural capital.• Relatively high diversity and productivityRelatively high diversity and productivity• Absorb floodwater and protect against tropical storms Absorb floodwater and protect against tropical storms

and tsunamisand tsunamis

– Human activities have degraded or destroyed the Human activities have degraded or destroyed the natural protection of coastal surface formationsnatural protection of coastal surface formations• Hurricanes, typhoons and tsunamis become partially Hurricanes, typhoons and tsunamis become partially

unnatural disasters (see Case Study, p. 140)unnatural disasters (see Case Study, p. 140)

– Streams shape the land over which they pass.Streams shape the land over which they pass.– Watershed must be the focus when we wish to Watershed must be the focus when we wish to

protect streams and rivers from excessive inputs protect streams and rivers from excessive inputs of nutrients and pollutants.of nutrients and pollutants.

• Freshwater Inland Wetlands: Vital SpongesFreshwater Inland Wetlands: Vital Sponges– Inland wetlandsInland wetlands – lands covered with freshwater – lands covered with freshwater

all or part of the time, excluding lakes, reservoirs, all or part of the time, excluding lakes, reservoirs, and streams, located away from coastal areas.and streams, located away from coastal areas.• MarshesMarshes• Swamps (Fig. 6-18)Swamps (Fig. 6-18)• Prairie potholesPrairie potholes• FloodplainsFloodplains• Arctic tundra in summerArctic tundra in summer

– When a wetland is dry, a wetland may be When a wetland is dry, a wetland may be recognized by soil composition and certain recognized by soil composition and certain plants.plants.

– Highly productiveHighly productive– Habitats for game fish, muskrats, otters, beavers, Habitats for game fish, muskrats, otters, beavers,

migratory waterfowl, and other birdsmigratory waterfowl, and other birds

– Inland wetlands provide free ecological and Inland wetlands provide free ecological and economic services.economic services.• Filter and degrade toxic wastes and pollutantsFilter and degrade toxic wastes and pollutants

– In US, worth at least $1.6 billion/yrIn US, worth at least $1.6 billion/yr

• Reduce flooding and erosion by absorbing and Reduce flooding and erosion by absorbing and releasing stormwater slowly, and by absorbing releasing stormwater slowly, and by absorbing overflows from streams and lakesoverflows from streams and lakes

– In US, worth $3-4 billion/yrIn US, worth $3-4 billion/yr

• Help replenish stream flows during dry periodsHelp replenish stream flows during dry periods• Help recharge groundwater aquifersHelp recharge groundwater aquifers• Help maintain biodiversityHelp maintain biodiversity• Supply valuable products such as fish and shellfish, Supply valuable products such as fish and shellfish,

blueberries, cranberries, wild rice, and timberblueberries, cranberries, wild rice, and timber• Provide recreation for birdwatchers, nature Provide recreation for birdwatchers, nature

photographers, boaters, anglers, and waterfowl photographers, boaters, anglers, and waterfowl huntershunters

• Impacts of Human Activities on Freshwater Impacts of Human Activities on Freshwater SystemsSystems– Four major impactsFour major impacts

• FirstFirst, dams, diversions, or canals fragment about 40% , dams, diversions, or canals fragment about 40% of world’s 237 large rivers.of world’s 237 large rivers.

• SecondSecond, flood control levees and dikes alter and , flood control levees and dikes alter and destroy aquatic habitats.destroy aquatic habitats.

• ThirdThird, cities and farmlands as pollutants and excess , cities and farmlands as pollutants and excess nutrients to watershed.nutrients to watershed.

• FourthFourth, draining or filling of inland wetlands to grow , draining or filling of inland wetlands to grow crops (Fig. 6-19) or have been converted with crops (Fig. 6-19) or have been converted with concrete, asphalt, and buildings.concrete, asphalt, and buildings.

• Case Study: Inland Wetland Losses in the United Case Study: Inland Wetland Losses in the United States (Science and Politics)States (Science and Politics)– In US 95% of wetlands are freshwater; remaining are In US 95% of wetlands are freshwater; remaining are

saltwater or coastal.saltwater or coastal.– Alaska has more wetlands than the other 49.Alaska has more wetlands than the other 49.– More than half the inland wetlands in continental US More than half the inland wetlands in continental US

have been lost since the 1600s.have been lost since the 1600s.• 80% for crops80% for crops• Rest for mining, forestry, oil and gas extraction, highways, and Rest for mining, forestry, oil and gas extraction, highways, and

urban developmenturban development• Iowa has lost 99%Iowa has lost 99%

– Loss of this natural capital has been an important factor Loss of this natural capital has been an important factor in increased flood and drought damage.in increased flood and drought damage.

– Other countries too: France and Germany lost 80%Other countries too: France and Germany lost 80%

A Healthy Coral Reef (Fig 6-1a)A Healthy Coral Reef (Fig 6-1a)

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Bleaching in Coral Reefs (6-1b)Bleaching in Coral Reefs (6-1b)

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The Ocean Planet (Figure 6-2)The Ocean Planet (Figure 6-2)

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Distribution of Major Oceans, Coral Reefs, Mangroves, and Distribution of Major Oceans, Coral Reefs, Mangroves, and Freshwater Lakes and Rivers (Figure 6-3)Freshwater Lakes and Rivers (Figure 6-3)

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(Fig. 6-4)(Fig. 6-4)

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Major Ocean Life Zones (Fig. 6-5)Major Ocean Life Zones (Fig. 6-5)

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Back to Back to Open SeaOpen Sea

Sediment Plume at Mouth of Madagascar’s Sediment Plume at Mouth of Madagascar’s Betsiboka River (Fig. 6-6)Betsiboka River (Fig. 6-6)

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Components and Interactions in a Components and Interactions in a Temperate Salt Marsh Ecosystem (Fig. 6-7)Temperate Salt Marsh Ecosystem (Fig. 6-7)

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Mangrove Forest in Daintree National Park Mangrove Forest in Daintree National Park In Queensland, Australia (Fig. 6-8)In Queensland, Australia (Fig. 6-8)

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Specialized Niches in a Rocky Specialized Niches in a Rocky Shore (Fig. 6-9)Shore (Fig. 6-9)

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Specialized Niches in a Sandy Specialized Niches in a Sandy Shore (Fig. 6-9b)Shore (Fig. 6-9b)

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Typical Barrier Island Profile Typical Barrier Island Profile (Fig. 6-10)(Fig. 6-10)

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Components and Interactions in a Components and Interactions in a Coral Reef Ecosystem (Fig. 6-11)Coral Reef Ecosystem (Fig. 6-11)

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Major Threats to Coral Reefs (Fig 6-12)Major Threats to Coral Reefs (Fig 6-12)

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Major Human Impacts on the World’s Major Human Impacts on the World’s Marine Systems (Fig. 6-13)Marine Systems (Fig. 6-13)

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Major Ecological and Economic Services Major Ecological and Economic Services (Fig. 6-14)(Fig. 6-14)

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Life Zones in a Temperate Zone Life Zones in a Temperate Zone Lake (Fig. 6-15)Lake (Fig. 6-15)

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Oligotrophic Lake (Fig. 6-16a)Oligotrophic Lake (Fig. 6-16a)

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Eutrophic Lake (Fig. 6-16b)Eutrophic Lake (Fig. 6-16b)

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Three Zones in the Downhill Flow of Water Three Zones in the Downhill Flow of Water (Fig. 6-17)(Fig. 6-17)

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Cypress Swamp in Tennessee (Fig. 6-18)Cypress Swamp in Tennessee (Fig. 6-18)

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Prairie Pothole Wetland That Has Been Prairie Pothole Wetland That Has Been Ditched and Drained for Cropland (Fig. 6-19)Ditched and Drained for Cropland (Fig. 6-19)

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