Transcript OCEAN POLLUTION

OCEAN
POLLUTION
How Pollution Gets into the Oceans
• At least 85% of ocean pollution comes from
activities on the land.
• Pollution can enter rivers and be carried
downstream near coasts where sensitive coastal
environments like reefs and estuaries (where
streams and rivers empty into coastal waters)
are the hardest hit.
• The rest of ocean pollution can be attributed to
pollutants being deliberately dumped into ocean
waters.
Pollutants
Pollutants get into oceans by one of several ways…
• Pollutants like sludge (wastewater treatment by-product)
and the wastewater or garbage from Ocean-liners can
be dumped directly into the oceans.
• Accidental oil spills such as the 1989 Exxon Valdez oil
spill at Prince William Sound, Alaska. About 5% of oil
spills happen in open ocean, the rest usually occur
during the loading and unloading of oil.
Plastic is a SERIOUS type of
oceanic pollution. Fishing lines
entangle and strangle marine life.
Turtles suffocate by eating clear plastic
bags thinking they are jellyfish. Sixpack plastic rings strangle sea birds
and cut fish.
The Great Pacific Garbage Patch
(Trash Vortex)
• The Great Pacific Garbage Patch, also described as the
Eastern Garbage Patch or the Pacific Trash Vortex is an
area of marine debris in the central North Pacific Ocean
located roughly in an area between 135° to 155°W and
35° to 42°N. The patch is characterized by exceptionally
high concentrations of suspended plastic and other
debris that have been trapped by the currents of the
North Pacific Gyre.
www.wikipedia.org
The Great Pacific Garbage Patch
(Trash Vortex)
• Like other areas of concentrated marine debris in the
world's oceans, the Eastern Garbage Patch has formed
gradually over the last decades as a result of higher
levels of marine pollution and the action of prevailing
oceanic currents.
• The rotational pattern of the North Pacific Gyre draws in
waste material from the reaches of the North Pacific
Ocean, including the coastal areas of North America and
Japan.
• As material circulates in the current, wind-driven surface
currents gradually move floating debris toward the
center, trapping it in the circular oceanic region.
www.sailworld.com
The Great Pacific Garbage Patch
(Trash Vortex)
• It is estimated that 80% of the garbage comes from landbased sources, and 20% from ships at sea.
• Currents carry debris from the east coast of Asia to the
center of the gyre in a year or less, and debris from the
west coast of North America in about five years.
• For every pound of plankton, there are 6 pounds of
garbage… maybe over 100 million tons (1T=2204 lbs)
• The size is somewhere between 1% and 8% of the entire
Pacific Ocean!
• CBC News Clip on North Pacific Gyre and Plastic Pollution
http://www.cbsnews.com/stories/2004/01/06/eveningnews/main591770.shtml
G Word Clip on Trash Vortex –
http://planetgreen.discovery.com/tv/g-word/ocean-trash.html
Preventing Ocean Pollution
• MARPOL or the International Convention for the
Prevention of Pollution from Ships, prohibits the
discharge of oil and plastic in oceanic and coastal
environments.
• The 1974 Helsinki Convention signed by 120 countries
seeks to control land-based pollution such as toxic
dumping, runoff and discharge of raw wastewater into
oceans. This agreement has also created 15 marine
refuges for endangered marine species, like the sea
turtle.
• It is very difficult to monitor every ship and the success of
these laws and conventions depends on all nations
obeying the laws and honouring the agreements.
Who Owns the Oceans?
• The Law of the Sea Treaty (signed by 134 countries
except the USA) gives countries control over 22km of
water extending from their coastlines. This area is called
the “territorial sea”. Up to 370km of water is considered
a country’s exclusive economic zone.
• The rest of the ocean is considered a communal
property good which falls under the International Seabed
Authority.
Questions
• What is the major kind of ocean pollution, point or nonpoint?
• How can plastic be eliminated from the oceans?
• Identify three things YOU could do at home to decrease
ocean pollution.