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Lesson N °12 :
Impact of shipping on the marine environment :
Even though shipping is the most climate-friendly form of commercial
transport it is not at all environmentally friendly.
Shipping is responsible for a number of prssures and risks to the seas
and oceans :discharge of hazardous substances such as oil , atmospheric
emissions , noise pollution , discharge and disposal of sewage and litter ,
introduction of non-indigenous species and risk of oil spill .
The release of airbone pollutants by ships has harmful impacts on the
ecosystem and the atmosphere . Of key importance
for the marine
environment are sulfur dioxide (SO 2 ) and nitrogen oxide ( NO 2 )
emissions that result in the acidification
and euthrophication of sea
water.
Heavy oil or bunker oil are used as fuel in ships . these oils have a high
sulfur content of around 3% , which leads to high SO 2 emissions.
Another problem is the emission of particulate matter , which not only
affects the climate but also human health. The most important
greenhouse gas emitted by by shipping is CO 2 . A large proportion of
emission are released near the coast.
As a consequence , atmospheric
emission from ships have created a serious quality problem in some
port cities.
Shipping is an important source of oil inputs in the sea. Oil enters the
marine environment via incidental , operational , illegal discharges and
accidental oil spills . oils and their components can damage the marine
esosystem in a variety of ways , such as toxic effects on organisms that
ingest oil components.
Other harmful substances in the marine environment stemming from
shipping are antifouling agents .
Ship traffic has been shown to be a major source of low-frequency noise
in the sea , especially in coastal waters.
Furthermore , shipping is the main vector
for introducing nonindigenous species in the seas and oceans . they are usually transported