Transcript Chapter 11: The coastal ocean

The Coastal Ocean
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
Characteristics of coastal waters
Adjacent to land (to edge of continental
shelf)
 Influenced by river runoff, wind, tides
 Salinity variable

 Freshwater runoff
 Winds
 Mixing by tides
Characteristics of coastal waters

Temperature variable
 Low-latitudes: restricted circulation, very
warm
 High-latitudes: sea ice
 Mid-latitudes
○ Seasonal changes
○ Prevailing winds
Types of coastal waters

Estuary
 Partially enclosed coastal area with ocean
water and freshwater (runoff) mixing; mouths
of rivers, bays, etc.
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Lagoon
 Shallow coastal water separated from ocean by
barrier island

Marginal sea
 Relatively large semi-isolated body of water
Estuaries - Origin of estuaries
Rising sea level “drowns” what
was once land
 Coastal plain estuary

 Former river valley now flooded with
seawater
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Fjord
 Former glaciated valley now flooded
with seawater
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Bar-built estuary
 Lagoon separated from ocean by sand
bar or barrier island

Tectonic estuary
 Faulted or folded down-dropped area
now flooded with ocean
Estuaries - Classification of estuaries
4 types - Based on mixing of freshwater and saltwater

Vertically mixed

Slightly stratified

Highly stratified

Salt wedge
 Shallow, low volume
 Salinity uniform
 Deeper than previous
 Upper layer less salty; lower layer more salty
 Estuarine circulation
 Deep, relatively strong halocline
 Deep, high volume
 Strong halocline
 Typical at mouths of deep, high volume rivers
Lagoons
Water isolated by barrier islands
 3 main zones:

○ Freshwater zone
○ Transition zone of brackish water
○ Saltwater zone

Hypersaline in arid regions
Indian River Lagoon
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
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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
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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
Coastal Wetlands - Types of coastal wetlands
o
o
o
Ecosystems that are saturated with
water
o Swamps, tidal flats, coastal
marshes, bayous
Salt marsh
o Any latitude
Mangroves
o 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

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Half of U.S. coastal
wetlands lost to
development (housing,
industry, agriculture)
U.S. Office of Wetland
Protection, 1986
 Minimize loss of
wetlands
 Protect or restore
wetlands
http://www.on.ec.gc.ca/wildlife/factsheets/images/glfs-coast-stress.jpg
Marine pollution

Any harmful substance or energy put into the
oceans by humans
 Harmful 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.
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

 Toxic
 Long life dissolved in seawater
 Accumulated in food chain
 Bioaccumulation – it’s happening in us, also!
Bioaccumulation and biomagnification
Bioaccumulation – organisms
concentrate pollutant from seawater
 Biomagnification – organisms gain more
pollutant by eating other organisms

DDT

Decline in bird
populations and thin
eggshells
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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 – numbness, muscle
weakness, paralysis, coma, congenital defects
Non-point-source pollution and
trash

Not from underwater pipelines
 Hard to regulate
 For example, from storm drains
 Pesticides and fertilizers
 Road oil
 Trash
Trash from dumping

Some trash can be legally
dumped far from shore
 Biodegradable (e.g., food) or
 Sinkable (e.g., glass, metal)

Some trash cannot be
dumped
 Plastic
○ 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!
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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 –What have we learned that
make the following statements false?
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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.
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Sunshine State Standards
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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.