CHAPTER 11 The Coastal Ocean

Overview Coastal waters support about 95% of total biomass in ocean Coastal waters support about 95% of total biomass in ocean Most commercial fish caught within 320 km (200 m) from shore Most commercial fish caught within 320 km (200 m) from shore Important also for shipping, oil and gas production, and recreation Important also for shipping, oil and gas production, and recreation Many pollutants found here Many pollutants found here

Ocean ownership 1609 sea is free to all (mare liberum) 1609 sea is free to all (mare liberum) Assumed fish resources are inexhaustible Assumed fish resources are inexhaustible 1702 territorial sea under coastal nation’s sovereignty (3 nautical miles from shore) 1702 territorial sea under coastal nation’s sovereignty (3 nautical miles from shore) Distance of cannon shot Distance of cannon shot

United Nations and ocean laws United Nations Law of the Sea Conferences United Nations Law of the Sea Conferences National sovereignty extends 12 nautical miles National sovereignty extends 12 nautical miles Exclusive Economic Zone (EEZ) 200 nautical miles (370 km) from land (mineral and fishing resources) Exclusive Economic Zone (EEZ) 200 nautical miles (370 km) from land (mineral and fishing resources) Right of free passage for ships Right of free passage for ships Open ocean mining regulated by International Seabed Authority Open ocean mining regulated by International Seabed Authority United Nations arbitrates disputes United Nations arbitrates disputes

EEZ of the U.S.--about 30% more than land area of entire U.S. Fig. 11.1

Characteristics of coastal waters Adjacent to land (to edge of continental shelf) Adjacent to land (to edge of continental shelf) Influenced by river runoff, wind, tides Influenced by river runoff, wind, tides Salinity variable Salinity variable Freshwater runoff Freshwater runoff Winds Winds Mixing by tides Mixing by tides

Characteristics of coastal waters Temperature variable Temperature variable Low-latitudes: restricted circulation, very warm Low-latitudes: restricted circulation, very warm High-latitudes: sea ice High-latitudes: sea ice Seasonal changes Seasonal changes Prevailing winds Prevailing winds

Salinity characteristics Fig. 11.2

Temperature characteristics Fig. 11.3

Coastal geostrophic currents Wind and runoff Wind and runoff Piled up surface water affected by Coriolis effect Piled up surface water affected by Coriolis effect Flow parallel to coast Flow parallel to coast Example, Davidson Current Example, Davidson Current

Fig. 11.4

Types of coastal waters Estuary Estuary Partially enclosed coastal area with ocean water and freshwater (runoff) mixing Partially enclosed coastal area with ocean water and freshwater (runoff) mixing Coastal wetland Coastal wetland Ecosystem with water table close to surface Ecosystem with water table close to surface Lagoon Lagoon Shallow coastal water separated from ocean Shallow coastal water separated from ocean Marginal sea Marginal sea Relatively large semi-isolated body of water Relatively large semi-isolated body of water

Origin of estuaries Rising sea level “drowns” what was once land Rising sea level “drowns” what was once land Coastal plain estuary Coastal plain estuary Former river valley now flooded with seawater Former river valley now flooded with seawater Fjord Fjord Former glaciated valley now flooded with seawater Former glaciated valley now flooded with seawater Bar-built estuary Bar-built estuary Lagoon separated from ocean by sand bar or barrier island Lagoon separated from ocean by sand bar or barrier island Tectonic estuary Tectonic estuary Faulted or folded downdropped area now flooded with ocean Faulted or folded downdropped area now flooded with ocean

Origin of estuaries

Classification of estuaries Based on mixing of freshwater and saltwater Vertically mixed Vertically mixed Shallow, low volume Shallow, low volume Slightly stratified Slightly stratified Deeper Deeper Upper layer less salty; lower layer more salty Upper layer less salty; lower layer more salty Estuarine circulation Estuarine circulation Highly stratified Highly stratified Deep, relatively strong halocline Deep, relatively strong halocline Salt wedge Salt wedge Deep, high volume Deep, high volume Strong halocline Strong halocline

Classification of estuaries Fig. 11.7c

Estuaries and human activities Important breeding grounds for many marine animals Important breeding grounds for many marine animals Protective nurseries Protective nurseries Pressures from increasing human populations Pressures from increasing human populations Columbia River estuary (salt wedge) Columbia River estuary (salt wedge) Damages due to dams, logging Damages due to dams, logging

Chesapeake Bay Estuary Slightly stratified Slightly stratified Seasonal changes in salinity, temperature, dissolved oxygen Seasonal changes in salinity, temperature, dissolved oxygen Anoxic conditions below pycnocline in summer Anoxic conditions below pycnocline in summer Major kills of commercially important marine animals Major kills of commercially important marine animals Fig. 11.9

Types of coastal wetlands Ecosystems saturated with water Ecosystems saturated with water Swamps, tidal flats, coastal marshes, bayous Swamps, tidal flats, coastal marshes, bayous Salt marsh Salt marsh Any latitude Any latitude Mangroves Mangroves Low latitude Low latitude

Characteristics of coastal wetlands Biologically important Biologically important Nurseries, feeding grounds for commercially important marine animals Nurseries, feeding grounds for commercially important marine animals Efficiently cleanse polluted water Efficiently cleanse polluted water Absorb water from coastal flooding Absorb water from coastal flooding Protect shores from wave erosion Protect shores from wave erosion

Loss of coastal wetlands Half of U.S. coastal wetlands lost to development (housing, industry, agriculture) Half of U.S. coastal wetlands lost to development (housing, industry, agriculture) U.S. Office of Wetland Protection, 1986 U.S. Office of Wetland Protection, 1986 Minimize loss of wetlands Minimize loss of wetlands Protect or restore wetlands Protect or restore wetlands Predicted rise in sea level over next 100 years will destroy or shift wetlands inland Predicted rise in sea level over next 100 years will destroy or shift wetlands inland

Lagoons Freshwater zone Freshwater zone Transition zone of brackish water Transition zone of brackish water Saltwater zone Saltwater zone Hypersaline in arid regions Hypersaline in arid regions Fig

Marginal seas Mostly from tectonic events Mostly from tectonic events Ocean crust between continents, e.g., Mediterranean Sea Ocean crust between continents, e.g., Mediterranean Sea Behind volcanic island arcs, e.g., Caribbean Sea Behind volcanic island arcs, e.g., Caribbean Sea Shallower than ocean Shallower than ocean Connected to ocean Connected to ocean

Mediterranean Sea Remnant of Tethys Sea Remnant of Tethys Sea Deeper than usual marginal sea Deeper than usual marginal sea Underlain by oceanic crust Underlain by oceanic crust Thick salt deposits Thick salt deposits Fig a

Mediterranean circulation Atlantic Ocean surface flow Atlantic Ocean surface flow High rates of evaporation High rates of evaporation Mediterranean Intermediate Water very salty Mediterranean Intermediate Water very salty Returns to Atlantic Ocean as subsurface flow Returns to Atlantic Ocean as subsurface flow Circulation opposite to estuarine circulation Circulation opposite to estuarine circulation Fig b

Marine pollution Any harmful substance or energy put into the oceans by humans Any harmful substance or energy put into the oceans by humans Harmful to living organisms Harmful to living organisms Standard laboratory bioassay – concentration of pollutant that causes 50% mortality among test organisms Standard laboratory bioassay – concentration of pollutant that causes 50% mortality among test organisms Hindrance to marine activities (e.g., fishing) Hindrance to marine activities (e.g., fishing) Reduction in quality of sea water Reduction in quality of sea water

Waste disposal in ocean Diluting pollutants with huge volume of ocean water Diluting pollutants with huge volume of ocean water Long term effects not known Long term effects not known Debate about dumping wastes in ocean Debate about dumping wastes in ocean None at all None at all Some, as long as properly disposed and monitored Some, as long as properly disposed and monitored

Main types of marine pollution Petroleum Petroleum Sewage sludge Sewage sludge DDTs and PCBs DDTs and PCBs Mercury Mercury Non-point-source pollution and trash Non-point-source pollution and trash

Petroleum Fig Oil spills due to accidents in transport Oil spills due to accidents in transport Blowout of undersea oil wells Blowout of undersea oil wells Example, Ixtoc #1, Gulf of Mexico, 1979 Example, Ixtoc #1, Gulf of Mexico, 1979

Petroleum Biodegradable hydrocarbons Biodegradable hydrocarbons Recovery faster than expected Recovery faster than expected Exxon Valdez oil spill, 1989 Exxon Valdez oil spill, 1989 But many organisms killed outright But many organisms killed outright Long-term consequences uncertain Long-term consequences uncertain Fig

Oil spills in U.S. Florida, Massachusetts, 1969 Florida, Massachusetts, 1969 Sharp reduction in species diversity in tidal flat areas Sharp reduction in species diversity in tidal flat areas Recovery in 3- 5 years Recovery in 3- 5 years Still oil in subsurface sediments (15 cm or 6 in) Still oil in subsurface sediments (15 cm or 6 in) Fig

Oil spills in U.S. Argo Merchant, Nantucket, 1976 Argo Merchant, Nantucket, 1976 No oil on shore No oil on shore Mainly plankton damaged Mainly plankton damaged Fig a

Cleaning oil spills Natural processes Natural processes Volatilization Volatilization Photo oxidation Photo oxidation Emulsification Emulsification Biodegration by pelagic organisms Biodegration by pelagic organisms Biodegration by benthic organisms Biodegration by benthic organisms Artificial processes Artificial processes Skimming or absorbing surface oil slick Skimming or absorbing surface oil slick Bioremediation by “hydrocarbon-eating” bacteria Bioremediation by “hydrocarbon-eating” bacteria

Cleaning oil spills Fig

Preventing oil spills Double hulled oil tankers by 2015 Double hulled oil tankers by Oil Pollution Act 1990 Oil Pollution Act Burn oil before it spreads Burn oil before it spreads 1999 M/V New Carissa 1999 M/V New Carissa

Sewage sludge Semisolid material after treatment Semisolid material after treatment No dumping of sludge in ocean after 1981 No dumping of sludge in ocean after 1981 Clean Water Act, 1972 Clean Water Act, 1972 Many exceptions/waivers Many exceptions/waivers

New York’s sewage sludge disposal First, shallow water sites First, shallow water sites Then (1986), deeper water site Then (1986), deeper water site Adverse effects on fish Adverse effects on fish 1993 all sewage disposed on land 1993 all sewage disposed on land Fig

Boston Harbor sewage project Cleanup of harbor where sewage dumped in shallow water Cleanup of harbor where sewage dumped in shallow water Treated sewage released into deep water via tunnels (1998) Treated sewage released into deep water via tunnels (1998) Fig a

DDT and PCBs Pesticide DDT Pesticide DDT Industrial chemicals PCBs (polychlorinated biphenyls) Industrial chemicals PCBs (polychlorinated biphenyls) Widespread in oceans Widespread in oceans Persistent organic pollutants Persistent organic pollutants Toxic Toxic Long life dissolved in seawater Long life dissolved in seawater Accumulated in food chain Accumulated in food chain

DDT Fig Decline in bird populations and thin eggshells Decline in bird populations and thin eggshells Long Island osprey Long Island osprey California brown pelican California brown pelican DDT banned in U.S. in 1972 DDT banned in U.S. in 1972 Some marine bird populations rebounded Some marine bird populations rebounded

Mercury and Minamata disease Methyl mercury toxic to most living organisms Methyl mercury toxic to most living organisms Chemical plants, Minamata Bay, Japan, released mercury in 1938 Chemical plants, Minamata Bay, Japan, released mercury in 1938 By 1950 first reported ecological changes By 1950 first reported ecological changes By 1953 humans poisoned By 1953 humans poisoned Neurological disorder Neurological disorder

Bioaccumulation and biomagnification Bioaccumulation – organisms concentrate pollutant from seawater Bioaccumulation – organisms concentrate pollutant from seawater Biomagnification – organisms gain more pollutant by eating other organisms Biomagnification – organisms gain more pollutant by eating other organisms Safe levels of mercury determined by Safe levels of mercury determined by Rate of fish consumption by people Rate of fish consumption by people Mercury concentration in fish consumed Mercury concentration in fish consumed Minimum ingestion rate of mercury to cause damages Minimum ingestion rate of mercury to cause damages

Bioaccumulation and biomagnification for mercury Fig

Non-point-source pollution and trash Not from underwater pipelines Not from underwater pipelines For example, from storm drains For example, from storm drains Trash Trash Pesticides and fertilizers Pesticides and fertilizers Road oil Road oil

Trash from dumping Some trash can be legally dumped far from shore Some trash can be legally dumped far from shore Biodegradable (e.g., food) or Biodegradable (e.g., food) or Sinkable (e.g., glass, metal) Sinkable (e.g., glass, metal) Some trash cannot be dumped Some trash cannot be dumped Plastic Plastic Lightweight (floats) Lightweight (floats) Not easily biodegradable Not easily biodegradable Plastic can incorporate pollutants, such as DDT and PCBs Plastic can incorporate pollutants, such as DDT and PCBs

End of CHAPTER 11 The Coastal Ocean Fig a