Transcript chapter20ppt

CHAPTER 19 & 20
Susquehanna
Patapsco
Chester
Potomac
Patuxent
Choptank
Nanticoke
Rappahannock
Pocomoke
York
James
THE CHESAPEAKE BAY
• largest estuarine system in the United States
• has a watershed of almost 64,000 square miles.
• This unique ecosystem also contains more than
1,500 square miles of wetlands that provide critical
habitat for fish, shellfish, and wildlife; filter and
process residential, agricultural, and industrial
wastes; and buffer coastal areas against storm and
wave damage.
THE CHESAPEAKE BAY
• Five major tributary systems--the Potomac,
Susquehanna, Rappahannock, York, and
James Rivers
• Major Problems facing the bay: Overfishing,
Overharvesting, Nutrient Overload, Toxic
Chemicals, Pollution, Habitat Destruction
“Clean Water Act”
Reading and Questions
POLLUTION
Ocean dumping
trash – 17th annual Coastal Cleanup in
September 2002
2.8 million lb. of trash and debris in 3 hours
1.3 million cigarette butts and filters
226,251 glass bottles
238,826 metal cans
2,529 syringes
61% of trash collected was plastic
82 animals found trapped in the debris
POLLUTION
Ocean dumping (continued)
plastic
strength and durability of plastic make it
one of the most hazardous materials in
the sea
commercial dumping
garbage, sewage and toxic chemicals
have been dumped into the New York
Bight since 1890
It is estimated there are more than 13,000 pieces of plastic
litter on every square kilometer of the ocean surface.
(1 Km= .6 miles)
THE WATERS OFF THE NEW YORK/NEW JERSEY COASTS WERE
ONCE SO CONTAMINATED THEY WERE THE JOKE OF THE NATION.
THE NY/NJ BIGHT WAS KNOWN AS THE "OCEAN DUMPING CAPITAL
OF THE WORLD" DUE TO EIGHT OCEAN DUMPSITES.
THIS MAP INDICATES THE LOCATION OF THESE OCEAN DUMPSITES.
POLLUTION
Ocean dumping (continued)
military refuse
discarded military hardware
and munitions
toxic gases and chemicals
radioactive wastes
disposal of radioactive
materials in trench subduction
zones has been proposed
In 1964, mustard gas canisters are pushed into the Atlantic Ocean off New
Jersey. Millions of pounds were dumped this way.
HUNDREDS OF DOLPHINS WASHED ASHORE IN VIRGINIA AND
NEW JERSEY SHORELINES IN 1987 WITH BURNS FROM TO
MUSTARD GAS EXPOSURE.
POLLUTION
Pollution via land and air
urban pollution
50% of the U.S. population lives within 50
miles of coastline (including the Great
Lakes)
this population needs energy, industry and
waste treatment
coastal seas and habitats are polluted by
associated runoff from land
pesticides, fertilizers, gasoline, oil, sewage,
chemicals used to treat sewage
POLLUTION
Pollution via land and air (continued)
pesticides and toxic materials from
industry
pesticides (e.g. DDT), toxic organic
compounds (e.g. PCBs), heavy metals
(e.g. mercury, lead, zinc, and chromium)
biological magnification—concentration
of toxins in the tissues of animals as
they are passed up the food chain
without being broken down or excreted
POLLUTION
Pollution via land and air (continued)
air pollution
sulfur dioxide from burning of fossil fuels can
precipitate in water and lower pH
greenhouse gases (e.g. CO2, methane)
contribute to global warming
global warning is thought to cause coral
bleaching, raise sea levels, killing corals that
must remain close to the surface to obtain
sufficient sunlight for zooxanthellae
POLLUTION
Nutrient pollution
human wastes
disease agents
coliform bacteria, found in the intestines of
many animals, are counted to monitor water
quality
eutrophication – leads to blooms of
phytoplankton and other marine microbes
increased productivity
sometimes, the addition of sewage and
animal wastes can boost the productivity of
a marine community
POLLUTION
Nutrient pollution (continued)
agricultural wastes
fertilizers and animal wastes have effects similar
to those of human wastes
pesticides are also found in runoff from farms
POLLUTION
Controlling pollution
legislation was passed to prohibit
dumping of sewage sludge or industrial
wastes in the ocean after Jan. 1, 1992
largest threat is increasing coastal
populations and improperly controlled
commercial and residential development
THE 11TH HOUR
POLLUTION
Petroleum pollution
petroleum products
crude oil contains aromatic hydrocarbons
and aliphatic hydrocarbons
aromatic hydrocarbons—molecules made
up of carbon atoms in ring structures (e.g.
benzene, naphthalen, cyclohexane)
POLLUTION
Petroleum pollution
petroleum products
aliphatic hydrocarbons—straight-chain
molecules (e.g. heptane, octane, nonane)
petroleum products are persistent, difficult for
microbes to degrade, and toxic to organisms
POLLUTION
Petroleum pollution (continued)
oil spills
largest oil spill in the U.S. was in March 1989,
when the tanker Exxon Valdez ran onto a
rocky reef 25 miles from Valdez, Alaska
largest and longest-lasting oil spill ever was in
June 1979, when an offshore oil well in the
Gulf of Mexico, the Ixtoc 1, blew out and
caught fire
oil spills are deadly for marine organisms
POLLUTION
Petroleum pollution (continued)
ecological effects of oil spills
effects on birds and mammals
effects on invertebrates and algae
community effects
BP OIL SPILL
BP OIL SPILL
210 million gallons
far bigger than Exxon Valdez, making it the
worst spill in American history.
The National Wildlife Federation reports
that already more than:
150 threatened or endangered sea
turtles are dead
316 sea birds, mostly brown pelicans and
northern gannets, have been found dead
POLLUTION
Petroleum pollution (continued)
oil spill cleanup
oil booms and oil skimmers help to
confine the spill to a smaller area
and recover some of the oil
straw is used to soak up the oil,
then burned
a bacterium genetically engineered
to degrade crude oil is being tested
HABITAT DESTRUCTION
Wetlands
provide nutrients, shelter and spawning
grounds for a variety of marine organisms
have been drained, filled or dredged to
provide more ground for industry,
channels into ports/harbors, and beachfront real estate
legislation now protects wetlands, but the
government continually changes the
definition of “wetlands”
HABITAT DESTRUCTION
Beaches
direct effects of beach use and
development on marine life
disturbs nesting sites of birds, sea
turtles and horseshoe crabs
destruction of habitat
interfering with natural processes
longshore currents—generated by waves
that break at an angle to the beach,
moving parallel to the beach
longshore transport process—transport
of sediments by longshore currents
Oceans in Peril:
Overfishing
AN OCEAN IN CRISIS
The oceans are facing collapse due to
overfishing.
According to the U.N. Food and
Agriculture Organization 75 percent of
the world's fisheries are now either
overexploited, fully exploited,
significantly depleted or recovering
from overexploitation.
Biggest single threat to marine
ecosystems today is
overfishing.
Overfishing: catching so many
fish that too few are left in
the ocean to reproduce at
rates that can sustain a
healthy population
Demand for fish is exceeding
ecological limits with
devastating impacts
Overfishing results in profound
changes in our oceans
A large yellow fin tuna
being cut up.
Yellow fin and big eye tuna
may be commercially
extinct in 3-5 years
BETTER CHOICES
Alaska King Crab
Catfish (farmed)
Clams
Crab: Blue, Dungeness, King
Crawfish
Halibut (Pacific)
Mussels (Black, Green-lipped)
Oysters (farmed)
Pollack (Alaska)
Prawns (trap-caught, Pacific)
Rock Lobster (Australian)
Salmon (Wild Alaskan)
Scallops (Bay - farmed)
Shrimp (US farmed)
Squid (Pacific)
Tilapia (farmed)
Tuna: Pacific Albacore
EPILOGUE
• Natural changes are small and
occur over long periods of time
• Changes caused by humans can
be instantaneous and involve
entire marine communities
• Understanding the underlying
patterns and processes of the sea
allows people to use the sea’s
resources without jeopardizing its
environmental or economic value
for the future