Oceans
Vitally Important to Our Planet
• Ocean conveyor (current) regulates world
temperatures by transporting heat from
tropical regions to northern regions
• Starting point of the Hydrological Cycle
(evaporation, water vapour, clouds, snow,
ice)
• Carbon sinks and producers of oxygen
(phytoplankton produce 25% of the world’s
oxygen)
Ocean Pollution
• Shared dumping
ground
• Shoreline areas,
which teem with
aquatic life are the
most polluted areas of
our oceans
• Rivers bring
agricultural, city and
industrial waste
• Tides bring pollutants
back to shore
Types of Marine Pollution
• Oil : in transit for our use
– Tanker accidents “Exxon Valdez”
• Biggest culprit “US” ; oil from drains, streets. The oily runoff
from a city of 5m people can be equivalent to one oil tanker
spill
• Bilges; past a problem but more regulation
• Technology now ‘fingerprinting oil’
• Satellite tracking
• Recycling of used oil
• Recreational boating
• Off shor oil drilling
• Illegal dumping by cruise ships
Can carry 2,600 people and 1200 crew
Many now have sewage treatment on board
Agricultural run-off
• fertilizers, pesticides and herbicides used to
increase crop yields
• Chemicals are not bio-degradable
• Rainwater washes them into streams
• Infiltration carries them through the soil and out,
often super-enrich these streams increasing
plant growth until it becomes oxygen starved –
eutrophication
• creating dead zones ; often near river mouths
Sewage
• waste from urban centers
– Cost to treat waste
– Primary treatment (just removing solids)
• Many urban centers barge waste out to sea and
dump it
• Worst Canadian centers, Victoria, Saint John,
Halifax, St. John’s
• Storm and sanitary sewers (combines snow this
has stopped in many centers)
• Industrial waste and thermal pollution
• Chemicals and heavy metals
Why Should We Be Concerned?
• Oceans like Tropical Rainforests
…oxygen, carbon dioxide and the
hydrologic cycle
• We might need to become ‘farmers of the
seas’