CHAPTER 11CHAPTER 11The Coastal OceanThe Coastal Ocean

Overview Overview Coastal waters support about 95% of Coastal waters support about 95% of

total biomass in oceantotal biomass in ocean Most commercial fish caught within Most commercial fish caught within

320 km (200 m) from shore320 km (200 m) from shore Important also for shipping, oil and Important also for shipping, oil and

gas production, and recreationgas production, and recreation Many pollutants found hereMany pollutants found here

Ocean ownershipOcean ownership 1609 sea is free to all (1609 sea is free to all (mare mare

liberumliberum)) Assumed fish resources are Assumed fish resources are

inexhaustibleinexhaustible 1702 territorial sea under coastal 1702 territorial sea under coastal

nation’s sovereignty (3 nautical nation’s sovereignty (3 nautical miles from shore)miles from shore) Distance of cannon shotDistance of cannon shot

United Nations and ocean United Nations and ocean lawslaws 1958-1982 United Nations 1958-1982 United Nations Law of the Law of the

SeaSea Conferences Conferences National sovereignty extends 12 nautical National sovereignty extends 12 nautical

milesmiles Exclusive Economic Zone (EEZ)Exclusive Economic Zone (EEZ) 200 200

nautical miles (370 km) from land nautical miles (370 km) from land (mineral and fishing resources)(mineral and fishing resources)

Right of free passage for shipsRight of free passage for ships Open ocean mining regulated by Open ocean mining regulated by

International Seabed AuthorityInternational Seabed Authority United Nations arbitrates disputesUnited Nations arbitrates disputes

EEZ of the U.S.--about 30% EEZ of the U.S.--about 30% more than land area of entire more than land area of entire U.S.U.S.

Fig. 11.1

Characteristics of coastal Characteristics of coastal waterswaters Adjacent to land (to edge of Adjacent to land (to edge of

continental shelf)continental shelf) Influenced by river runoff, wind, Influenced by river runoff, wind,

tidestides Salinity variableSalinity variable

Freshwater runoffFreshwater runoff WindsWinds Mixing by tidesMixing by tides

Characteristics of coastal Characteristics of coastal waterswaters Temperature variableTemperature variable

Low-latitudes: restricted Low-latitudes: restricted circulation, very warmcirculation, very warm

High-latitudes: sea iceHigh-latitudes: sea ice Seasonal changesSeasonal changes Prevailing windsPrevailing winds

Salinity characteristicsSalinity characteristics

Fig. 11.2

Temperature characteristicsTemperature characteristics

Fig. 11.3

Coastal geostrophic Coastal geostrophic currentscurrents Wind and runoffWind and runoff Piled up surface water affected by Piled up surface water affected by

Coriolis effectCoriolis effect Flow parallel to coastFlow parallel to coast

Example, Davidson CurrentExample, Davidson Current

Fig. 11.4

Types of coastal watersTypes of coastal waters EstuaryEstuary

Partially enclosed coastal area with ocean Partially enclosed coastal area with ocean water and freshwater (runoff) mixingwater and freshwater (runoff) mixing

Coastal wetlandCoastal wetland Ecosystem with water table close to surfaceEcosystem with water table close to surface

LagoonLagoon Shallow coastal water separated from oceanShallow coastal water separated from ocean

Marginal seaMarginal sea Relatively large semi-isolated body of waterRelatively large semi-isolated body of water

Origin of Origin of estuariesestuaries Rising sea level “drowns” what was once landRising sea level “drowns” what was once land Coastal plain estuaryCoastal plain estuary

Former river valley now flooded with Former river valley now flooded with seawaterseawater

FjordFjord Former glaciated valley now flooded with Former glaciated valley now flooded with

seawaterseawater Bar-built estuaryBar-built estuary

Lagoon separated from ocean by sand bar Lagoon separated from ocean by sand bar or barrier islandor barrier island

Tectonic estuaryTectonic estuary Faulted or folded downdropped area now Faulted or folded downdropped area now

flooded with oceanflooded with ocean

Origin of Origin of estuariesestuaries

Classification of Classification of estuariesestuariesBased on mixing of freshwater and saltwaterBased on mixing of freshwater and saltwater Vertically mixedVertically mixed

Shallow, low volumeShallow, low volume Slightly stratifiedSlightly stratified

DeeperDeeper Upper layer less salty; lower layer more Upper layer less salty; lower layer more

saltysalty Estuarine circulationEstuarine circulation

Highly stratifiedHighly stratified Deep, relatively strong haloclineDeep, relatively strong halocline

Salt wedgeSalt wedge Deep, high volumeDeep, high volume Strong haloclineStrong halocline

Classification of estuariesClassification of estuaries

Fig. 11.7c

Estuaries and human Estuaries and human activitiesactivities Important breeding grounds for Important breeding grounds for

many marine animalsmany marine animals Protective nurseries Protective nurseries Pressures from increasing human Pressures from increasing human

populationspopulations Columbia River estuary (salt wedge)Columbia River estuary (salt wedge) Damages due to dams, loggingDamages due to dams, logging

Chesapeake Bay Chesapeake Bay EstuaryEstuary Slightly stratifiedSlightly stratified Seasonal changes Seasonal changes

in salinity, in salinity, temperature, temperature, dissolved oxygendissolved oxygen

Anoxic conditionsAnoxic conditions below pycnocline in below pycnocline in summersummer

Major kills of Major kills of commercially commercially important marine important marine animalsanimals

Fig. 11.9

Types of coastal wetlandsTypes of coastal wetlands Ecosystems saturated with waterEcosystems saturated with water

Swamps, tidal flats, coastal marshes, Swamps, tidal flats, coastal marshes, bayousbayous

Salt marshSalt marsh Any latitudeAny latitude

MangrovesMangroves Low latitudeLow latitude

Characteristics of coastal Characteristics of coastal wetlandswetlands Biologically importantBiologically important

Nurseries, feeding grounds for Nurseries, feeding grounds for commercially important marine commercially important marine animalsanimals

Efficiently cleanse polluted waterEfficiently cleanse polluted water Absorb water from coastal Absorb water from coastal

floodingflooding Protect shores from wave erosionProtect shores from wave erosion

Loss of coastal wetlandsLoss of coastal wetlands Half of U.S. coastal wetlands lost to Half of U.S. coastal wetlands lost to

development (housing, industry, development (housing, industry, agriculture)agriculture)

U.S. Office of Wetland Protection, U.S. Office of Wetland Protection, 19861986 Minimize loss of wetlandsMinimize loss of wetlands Protect or restore wetlandsProtect or restore wetlands

Predicted rise in sea level over next Predicted rise in sea level over next 100 years will destroy or shift 100 years will destroy or shift wetlands inlandwetlands inland

Lagoons Lagoons Freshwater Freshwater

zonezone Transition zone Transition zone

of brackish of brackish waterwater

Saltwater zoneSaltwater zone Hypersaline in Hypersaline in

arid regionsarid regions

Fig. 11.11

Marginal seasMarginal seas Mostly from tectonic eventsMostly from tectonic events

Ocean crust between continents, Ocean crust between continents, e.g., Mediterranean Seae.g., Mediterranean Sea

Behind volcanic island arcs, e.g., Behind volcanic island arcs, e.g., Caribbean SeaCaribbean Sea

Shallower than oceanShallower than ocean Connected to oceanConnected to ocean

Mediterranean SeaMediterranean Sea Remnant of Tethys Sea Remnant of Tethys Sea Deeper than usual marginal seaDeeper than usual marginal sea Underlain by oceanic crustUnderlain by oceanic crust Thick salt deposits Thick salt deposits

Fig. 11.13a

Mediterranean circulationMediterranean circulation

Atlantic Ocean surface flowAtlantic Ocean surface flow High rates of evaporationHigh rates of evaporation Mediterranean Intermediate Water very saltyMediterranean Intermediate Water very salty Returns to Atlantic Ocean as subsurface flowReturns to Atlantic Ocean as subsurface flow Circulation opposite to estuarine circulationCirculation opposite to estuarine circulation

Fig. 11.13b

Marine pollutionMarine pollution Any harmful substance or energy put Any harmful substance or energy put

into the oceans by humansinto the oceans by humans Harmful to living organismsHarmful to living organisms

Standard laboratory bioassay – Standard laboratory bioassay – concentration of pollutant that causes concentration of pollutant that causes 50% mortality among test organisms50% mortality among test organisms

Hindrance to marine activities (e.g., Hindrance to marine activities (e.g., fishing)fishing)

Reduction in quality of sea waterReduction in quality of sea water

Waste disposal in oceanWaste disposal in ocean Diluting pollutants with huge volume Diluting pollutants with huge volume

of ocean waterof ocean water Long term effects not knownLong term effects not known Debate about dumping wastes in Debate about dumping wastes in

oceanocean None at allNone at all Some, as long as properly disposed Some, as long as properly disposed

and monitoredand monitored

Main types of marine Main types of marine pollutionpollution PetroleumPetroleum Sewage sludgeSewage sludge DDTs and PCBsDDTs and PCBs MercuryMercury Non-point-source pollution and Non-point-source pollution and

trashtrash

PetroleuPetroleum m

Fig. 11.14

Oil spillsOil spills due to due to accidents in accidents in transporttransport

Blowout of Blowout of undersea oil undersea oil wellswells Example, Example,

Ixtoc #1, Ixtoc #1, Gulf of Gulf of Mexico, Mexico, 19791979

PetroleumPetroleum Biodegradable Biodegradable

hydrocarbonshydrocarbons Recovery faster Recovery faster

than expectedthan expected Exxon ValdezExxon Valdez oil oil

spill, 1989spill, 1989 But many But many

organisms killed organisms killed outrightoutright

Long-term Long-term consequences consequences uncertainuncertain

Fig. 11.15

Oil spills in Oil spills in U.S.U.S.

FloridaFlorida, , MassachusettsMassachusetts, 1969, 1969 Sharp Sharp

reduction in reduction in species species diversity in diversity in tidal flat tidal flat areasareas

Recovery in Recovery in 3-5 years3-5 years

Still oil in Still oil in subsurface subsurface sediments sediments (15 cm or 6 (15 cm or 6 in)in)

Fig. 11.18

Oil spills in U.S.Oil spills in U.S. Argo MerchantArgo Merchant, Nantucket, 1976, Nantucket, 1976

No oil on shoreNo oil on shore Mainly plankton damagedMainly plankton damaged

Fig. 11.19a

Cleaning oil spillsCleaning oil spills Natural processesNatural processes

VolatilizationVolatilization Photo oxidationPhoto oxidation EmulsificationEmulsification Biodegration by pelagic organismsBiodegration by pelagic organisms Biodegration by benthic organismsBiodegration by benthic organisms

Artificial processesArtificial processes Skimming or absorbing surface oil slickSkimming or absorbing surface oil slick Bioremediation by “hydrocarbon-eating” Bioremediation by “hydrocarbon-eating”

bacteriabacteria

Cleaning oil spillsCleaning oil spills

Fig. 11.21

Preventing oil spillsPreventing oil spills Double hulled oil tankers by Double hulled oil tankers by

20152015 1990 Oil Pollution Act1990 Oil Pollution Act

Burn oil before it spreadsBurn oil before it spreads 1999 M/V 1999 M/V New CarissaNew Carissa

Sewage sludgeSewage sludge

Semisolid material after Semisolid material after treatmenttreatment

No dumping of sludge in ocean No dumping of sludge in ocean after 1981after 1981 Clean Water Act, 1972Clean Water Act, 1972

Many exceptions/waiversMany exceptions/waivers

New York’s sewage sludge New York’s sewage sludge disposaldisposal First, shallow First, shallow

water siteswater sites Then (1986), Then (1986),

deeper water deeper water site site

Adverse effects Adverse effects on fishon fish

1993 all sewage 1993 all sewage disposed on landdisposed on land

Fig. 11.24

Boston Harbor sewage Boston Harbor sewage projectproject

Cleanup of harbor where sewage dumped in Cleanup of harbor where sewage dumped in shallow watershallow water

Treated sewage released into deep water Treated sewage released into deep water via tunnels (1998)via tunnels (1998)

Fig. 11.25a

DDT and PCBsDDT and PCBs Pesticide DDTPesticide DDT Industrial chemicals PCBs Industrial chemicals PCBs

(polychlorinated biphenyls)(polychlorinated biphenyls) Widespread in oceansWidespread in oceans Persistent organic pollutantsPersistent organic pollutants

ToxicToxic Long life dissolved in seawaterLong life dissolved in seawater Accumulated in food chainAccumulated in food chain

DDTDDT

Fig. 11.26

Decline in bird Decline in bird populations and populations and thin eggshellsthin eggshells Long Island Long Island

ospreyosprey California brown California brown

pelicanpelican DDT banned in DDT banned in

U.S. in 1972U.S. in 1972 Some marine Some marine

bird populations bird populations reboundedrebounded

Mercury and Minamata diseaseMercury and Minamata disease

Methyl mercury toxic to most living Methyl mercury toxic to most living organismsorganisms

Chemical plants, Minamata Bay, Japan, Chemical plants, Minamata Bay, Japan, released mercury in 1938released mercury in 1938

By 1950 first reported ecological changesBy 1950 first reported ecological changes By 1953 humans poisonedBy 1953 humans poisoned

Neurological disorderNeurological disorder

Bioaccumulation and Bioaccumulation and biomagnificationbiomagnification Bioaccumulation – organisms Bioaccumulation – organisms

concentrate pollutant from seawaterconcentrate pollutant from seawater Biomagnification – organisms gain Biomagnification – organisms gain

more pollutant by eating other more pollutant by eating other organismsorganisms

Safe levels of mercury determined bySafe levels of mercury determined by Rate of fish consumption by peopleRate of fish consumption by people Mercury concentration in fish consumedMercury concentration in fish consumed Minimum ingestion rate of mercury to Minimum ingestion rate of mercury to

cause damagescause damages

Bioaccumulation and Bioaccumulation and biomagnification for mercurybiomagnification for mercury

Fig. 11.28

Non-point-source pollution and Non-point-source pollution and trashtrash Not from underwater pipelinesNot from underwater pipelines

For example, from storm drainsFor example, from storm drains TrashTrash Pesticides and fertilizersPesticides and fertilizers Road oil Road oil

Trash from dumpingTrash from dumping Some trash can be legally dumped Some trash can be legally dumped

far from shorefar from shore Biodegradable (e.g., food) orBiodegradable (e.g., food) or Sinkable (e.g., glass, metal)Sinkable (e.g., glass, metal)

Some trash cannot be dumpedSome trash cannot be dumped PlasticPlastic

Lightweight (floats)Lightweight (floats) Not easily biodegradableNot easily biodegradable Plastic can incorporate pollutants, Plastic can incorporate pollutants,

such as DDT and PCBssuch as DDT and PCBs

End of CHAPTER 11End of CHAPTER 11The Coastal OceanThe Coastal Ocean

Fig. 11.31a