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CHAPTER 11The Coastal Ocean
Overview
Coastal waters support about 95% of total biomass in ocean
Most commercial fish caught within 320 km (200 m) from shore
Important also for shipping, oil and gas production, and recreation
Many pollutants found here – that’s a problem!
http://www.safmc.net/Portals/0/shrimp%20trawler2.jpg
Ocean ownership 1609 sea is free to all (mare liberum = free)
Assumed fish resources are inexhaustible
1702 territorial sea under coastal nation’s sovereignty (3 nautical miles from shore)Distance of cannon shot
http://www.kid-friendly-family-vacations.com/image-files/fort_sumter.jpg
Fort Sumter, Charleston harbor, South Carolina
United Nations and ocean laws 1958-1982 United Nations
Law of the SeaLaw of the Sea ConferencesNational sovereignty extends 12
nautical milesExclusive Economic Zone (EEZ)Exclusive Economic Zone (EEZ)
200 nautical miles (370 km) from land (mineral and fishing resources)
Right of free passage for shipsOpen ocean mining regulated by
International Seabed Authority○ This has changed, still very
contentiousUnited Nations arbitrates disputes
http://upload.wikimedia.org/wikipedia/commons/thumb/7/7d/Zonmar-en.svg/300px-Zonmar-en.svg.png
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) Influenced by river runoff, wind,
tides Salinity variable
Freshwater runoffWindsMixing by tides
http://upload.wikimedia.org/wikipedia/commons/5/58/Outer_Continental_Shelf_map.png
Characteristics of coastal waters Temperature variable
Low-latitudes: restricted circulation, very warm
High-latitudes: sea iceMid-latitudes○ Seasonal changes○ Prevailing winds
Types of coastal waters EstuaryEstuary
Partially enclosed coastal area with ocean water and freshwater (runoff) mixing
Coastal wetlandCoastal wetlandEcosystem with water table close to
surface Lagoon – type of estuaryLagoon – type of estuary
Shallow coastal water separated from ocean
Marginal seaMarginal seaRelatively large semi-isolated body of water
Estuaries - Origin of estuaries Rising sea level “drowns”
what was once land Coastal plain estuaryCoastal plain estuary
Former river valley now flooded with seawater
FjordFjord Former glaciated valley now flooded
with seawater Bar-built estuaryBar-built estuary
Lagoon separated from ocean by sand bar or barrier island
Tectonic estuaryTectonic estuary Faulted or folded down-dropped area
now flooded with ocean
Estuaries - Classification of estuaries4 types - Based on mixing of freshwater and
saltwater
Vertically mixedVertically mixed Shallow, low volume Salinity uniform
Slightly stratifiedSlightly stratified Deeper than previous Upper layer less salty; lower layer more salty Estuarine circulation
Highly stratifiedHighly stratified Deep, relatively strong halocline
Salt wedgeSalt wedge Deep, high volume Strong halocline Typical at mouths of deep, high volume rivers
Figure 11.8
Severely effected by human activity, freshwater wedge can be traceable far out to sea
Indian River Lagoon Estuary Well-mixed due to winds
and shallow depths Seasonal changes in
salinity, temperature, dissolved oxygen
Most biologically diverse estuary in north america…over 4,000 species of plants and animals
Threats: habitat destruction, stormwater runoff, and invasive exotic species
http://www.indianriverlagoon.org/docs/irlmap.html
Sebastian Inlet
Chesapeake Bay Estuary
Anoxic conditionsAnoxic conditions below pycnocline in summer Runoff of sewage and fertilizer cause algae bloom when these organisms die, increased decomposition causes
anoxic conditions Decrease in oxygen levels in water
Major kills of commercially important marine animals
Coastal Wetlands - Types of coastal wetlands
o Ecosystems that are saturated with watero Swamps, tidal flats, coastal
marshes, bayous
o Salt marsho Any latitude
o Mangroveso Low latitude
Characteristics of coastal wetlands Efficiently cleanse polluted water Absorb water from coastal flooding
during storms Protect shores from wave erosion
http://soundwaves.usgs.gov/2008/03/WetlandLG.jpg
Coastal Wetlands - Loss of coastal wetlands Half of U.S. coastal
wetlands lost to development (housing, industry, agriculture)
U.S. Office of Wetland Protection, 1986Minimize loss of
wetlandsProtect or restore
wetlands
http://www.on.ec.gc.ca/wildlife/factsheets/images/glfs-coast-stress.jpg
Lagoons Freshwater zone Transition zone of brackish water Saltwater zone Hypersaline in arid regions
Marginal seas Mostly from tectonic events
Ocean crust between continents, e.g., Mediterranean Sea
Behind volcanic island arcs, e.g., Caribbean Sea
Shallower than ocean Connected to ocean
http://www.shinesforall.com/images/Caribbeanmap.gif
Caribbean Sea On Caribbean plate defined by Greater
and Lesser Antilles – volcanic island arc Relatively shallow marginal sea – deepest
is Cancun Trough at 7,686 m (25,220 ft) Underlain by oceanic crust
http://woodshole.er.usgs.gov/project-pages/caribbean/images/PBATHY1.GIF
Mediterranean Sea Remnant of Tethys Sea – when all the continents
were together Deeper than usual marginal sea Underlain by oceanic crust Thick salt deposits – almost dried up about 6
million years ago
Fig. 11.14a
Mediterranean circulation
High rates of evaporation Mediterranean Intermediate Water very
salty
Fig. 11.14b
Marine pollution Any harmful substance or energy put into
the oceans by humansHarmful to living organisms○ Standard laboratory bioassay – concentration of pollutant
that causes 50% mortality among test organisms
Hindrance to marine activities (e.g., fishing)Reduction in quality of sea water
Waste disposal in ocean Diluting pollutants with huge volume of
ocean water Long-term effects not known Debate about dumping wastes in ocean
None at all ??Some, as long as properly disposed and
monitored ??
Main types of marine pollution Petroleum Nutrient excess
○ Sewage sludge○ Fertilizer runoff
DDTs and PCBs Mercury Non-point-source pollution and trash
○ Drainage from roads, canals, etc.
Petroleum Biodegradable Biodegradable
hydrocarbonshydrocarbonsRecovery faster than
expected○ Exxon Valdez oil
spill, 1989But many organisms
killed outrightLong-term
consequences uncertain○ Research is still
being done in this area, some animal populations have not completely recovered
Fig. 11.16
BP Deepwater Horizon Oil Spill in Gulf of MexicoApril 20, 20104.9 MILLION barrels of oil were leakedWhat are future effects?
Cleaning oil spills Natural
processesVolatilizationPhoto oxidationEmulsificationBiodegration by
pelagic organisms
Biodegration by benthic organisms
Artificial processesOil dispersantsIsolate spill with
boomsSkimming or
absorbing surface oil slick
Bioremediation by “hydrocarbon-eating” bacteria
Preventing oil spills Double hulled oil tankers by
20151990 Oil Pollution Act
Burn oil before it spreads1999 M/V New Carissa
http://www.modelshipmaster.com/products/ocean_liners/tube.jpg
http://www.ec.gc.ca/EnviroZine/images/aerial.jpg
Sewage sludge
Semisolid material after treatment No dumping of sludge in ocean after
1981Clean Water Act, 1972
HOWEVER - many exceptions/waivers
New York’s sewage sludge disposal
First, shallow water sites
Then (1986), deeper water site
Adverse effects on fish 1993 all sewage
disposed on land
Fig. 11.25
DDT and PCBs Pesticide DDT and industrial chemicals
PCBs (polychlorinated biphenyls)○ DDT – pesticide that was widely used○ PCBs – used in transformers and other areas of
industry
Widespread in oceans Persistent organic pollutants
ToxicLong life dissolved in seawaterAccumulated in food chain
Bioaccumulation – it’s happening in us, also!
Bioaccumulation and biomagnification BioaccumulationBioaccumulation – organisms
concentrate pollutant from seawater BiomagnificationBiomagnification – organisms gain
more pollutant by eating other organisms
DDT
Decline in bird populations and thin eggshells Long Island osprey California brown
pelican
DDT banned in U.S. in 1972
Some marine bird populations rebounded
Mercury and Minamata disease
Methyl mercury toxic to most living organisms
Chemical plants, Minamata Bay, Japan, released mercury in 1938
By 1950 first reported ecological changes By 1953 humans poisoned
Neurological disorder
Bioaccumulation and biomagnification
Safe levels of mercury determined byRate of fish
consumption by people
Mercury concentration in fish consumed
Minimum ingestion rate of mercury to cause damages
Non-point-source pollution and trash Not from underwater pipelines
Hard to regulateFor example, from storm drainsPesticides and fertilizersRoad oil Trash
Trash from dumping Some trash can be legally
dumped far from shoreBiodegradable (e.g., food) orSinkable (e.g., glass, metal)
Some trash cannot be dumpedPlastic○ Lightweight (floats)○ Not easily biodegradable○ Plastic can incorporate
pollutants, such as DDT and PCBs
http://www.sciencepunk.com/v5/gallery/greenpeace_table.JPG
It is up to us!
Don’t throw trash out your car window Don’t leave trash on the beach Don’t throw trash off the side of your
boat Don’t use fertilizers irresponsibly Don’t just dump things down the drain
without reading about proper disposal Get onto people you know that do this!
○ Think of your kids and grandkids!
Problems with Contaminants in Oceans Research into immunosuppression
and reproductive problems in many species
Chemicals that are banned in US and other countries are still used in others – it is 1 ocean, doesn’t matter where it is dumped○ It will effect us all!
All drains lead to the ocean!
Fig. 11.32a,b
Misconceptions Science and technology can solve all of our
problems. The Earth can absorb and neutralize any amount of
waste and pollution over time. Dilution is the solution to the problem. Microorganisms are not important to human survival. Local people cannot improve their environments; it is
out of their hands. If we run out of oil and gas we will just find more. Earth is both an endless supply of resources and a
limitless sink for the waste products of our society.
Ocean Literacy Principles 1.d - Sea level is the average height of the ocean relative to the
land, taking into account the differences caused by tides. Sea level changes as plate tectonics cause the volume of ocean basins and the height of the land to change. It changes as ice caps on land melt or grow. It also changes as sea water expands and contracts when ocean water warms and cools.
1.h - Although the ocean is large, it is finite and resources are limited.
5.f - Ocean habitats are defined by environmental factors. Due to interactions of abiotic factors such as salinity, temperature, oxygen, pH, light, nutrients, pressure, substrate and circulation, ocean life is not evenly distributed temporally or spatially, i.e., it is “patchy”. Some regions of the ocean support more diverse and abundant life than anywhere on Earth, while much of the ocean is considered a desert.
5.i - Estuaries provide important and productive nursery areas for many marine and aquatic species.
Sunshine State Standards SC.6.E.6.1 - Describe and give examples of ways in which Earth's surface is built up and torn down by
physical and chemical weathering, erosion, and deposition. SC.6.E.6.2 - Recognize that there are a variety of different landforms on Earth's surface such as coastlines,
dunes, rivers, mountains, glaciers, deltas, and lakes and relate these landforms as they apply to Florida. SC.912.E.6.6 - Analyze past, present, and potential future consequences to the environment
resulting from various energy production technologies. SC.912.L.17.2 - Explain the general distribution of life in aquatic systems as a function of chemistry,
geography, light, depth, salinity, and temperature. SC.912.L.17.3 - Discuss how various oceanic and freshwater processes, such as currents, tides, and
waves, affect the abundance of aquatic organisms. SC.912.L.17.8 - Recognize the consequences of the losses of biodiversity due to catastrophic events,
climate changes, human activity, and the introduction of invasive, nonnative species. SC.912.L.17.11 - Evaluate the costs and benefits of renewable and nonrenewable resources, such as
water, energy, fossil fuels, wildlife, and forests. SC.912.L.17.13 - Discuss the need for adequate monitoring of environmental parameters when making
policy decisions. SC.912.L.17.16 - Discuss the large-scale environmental impacts resulting from human activity, including
waste spills, oil spills, runoff, greenhouse gases, ozone depletion, and surface and groundwater pollution.
SC.912.L.17.20 - Predict the impact of individuals on environmental systems and examine how human lifestyles affect sustainability.