Transcript Benefits and Threats to Ocean

Benefits of & Threats
to Oceans
Ecology
March 10, 2009
Troubled Waters
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In January 1998, more than 1,600 marine
scientists and conservation biologists from
65 countries have issued an unprecedented
warning to the world's governments and
citizens that the sea is in trouble.
Troubled Waters paints a dismaying picture
of the destruction of marine biological
diversity.
“Year of the Ocean”
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Today, more than two-thirds of the world's
population live within 50 kilometers of the
ocean -- a figure that will likely rise to 75
percent by 2020.
To increase awareness of human impacts on
the world's oceans and the many resources
that the ocean sup plies, the United Nations
named 1998 as the Year of the Ocean
(YOTO).
Most serious threats today… #1
 Species
Overexploitation
 Overfishing
& overhunting of specific
organisms results in a loss of
biodiversity
 Ex:
octopus
in Morocco
Most serious threats today… #2
 Habitat
Degradation
 Destruction
of coral reefs, mangrove
forests, salt marshes, etc. for
development construction, tourism,
mining, & other commercial ventures.
 Damage to the sea floor by huge factor
“trawlers” that drag heavy nets across
the bottom along the continental
shelves, and deep sea floor mining
operations.
Most serious threats today… #3
 Pollution
 Excessive
nutrients (ex: Dead Zone* in
the Gulf of Mexico), fertilizers
(nitrogen & phosphorous), pesticides,
persistent toxic organic pollutants
(POPs) such as PCBs (which can
bioaccumulate in fatty tissue), trash
(ex: plastic), etc. from dumping or
runoff from land.
* Hypoxia (no O2)
A note about
PCBs

PCBs =
Polychlorinated
biphenyls

Found in coolants
and lubricants

Manufacture of
PCBs stopped in
United States in 1977
Most serious threats today… #4
 Upsetting
Balanced Marine
Ecosystems
 Predator-prey
relationships are
disrupted  leads to a steep decline in
the population of some species and
population explosions of other species.
 Ex:
Think about what we learned
about the stellar sea lions in Alaska
Most serious threats today… #5
 Climate
 Global
Change
warming is causing a rise in
ocean levels (melting ice sheets), more
intense storms, & a rise in ocean
temperatures which
can result in the loss
of some species
including plankton
(the base of all
marine ecosystems).
Most serious threats today… #6
 Ozone
 The
Depletion
depletion of the protective ozone
layer allows UV rays to penetrate and
affect
photosynthesis
and even kill
phytoplankton.
Benefits we gain…#1
 Food
 Nearly
1 billion people depend on fish
for 30% of their animal protein.
Benefits we gain…#2
 Transportation
 Includes
sea trade, fishing ships, oil
tankers, aircraft carriers, etc.
 90% of international trade moves by
ocean!!
Benefits we gain…#3
 Mining
 For
sand, gravel, coral, & minerals
(Mg, Au, Ni, and Cu  magnesium,
gold, nickel, & copper) in deep sea
deposits.
Benefits we gain…#4
 Medicines
 Many
current medicines are
produced from chemicals found in
sea organisms, and there is the
potential for many new discoveries.
 Ex: A chemical found in dogfish is
now used to stop the spread of
cancer.
Benefits we gain…#5
 Biological
 32/33
Diversity
types of life forms live in the
ocean.
 Only insects are missing
Benefits we gain…#6
 Oxygen
Production
 Phytoplankton
photosynthesizing in
the ocean (which covers over 70% of
the globe) produce oxygen for the
atmosphere.
 Oxygen exchange between water and
atmosphere.
Benefits we gain…#7
 Regulating
Climate (Global
Warming)
 The
photosynthesizing plankton
remove carbon dioxide form the
atmosphere and most of the world’s
carbon is sequestered in ocean
sediments.
 Carbon dioxide exchange between
atmosphere & water.
Efforts Needed to Save
Oceans
Take out a piece of
paper & write down
what to study for
upcoming test…
See side board
Ecology
March 11, 2009
Efforts Needed to Save Oceans…#1
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Replanting mangrove
trees in warm coastal
areas, saving coastal
wetlands & artificial
reefs
 Serve
as “nurseries” &
shelters for many
marine organisms
(many of which are
endangered)
Efforts Needed to Save Oceans…#2
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Establishing marine refuges & sanctuaries
 Places
where fish & marine mammals can have
a chance to safely reproduce & increase their
numbers
A scuba-diving
researcher
investigating
changes to corals in
the Florida Keys
National Marine
Sanctuary.
(Credit: NOAA)
Efforts Needed to Save Oceans…#3
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Promoting sustainable fish harvesting
methods
 Devise
safer, less
destructive fishing methods
 Put limits on the # of
endangered species that
can be fished legally.
Cod, herring, halibut, flounder, etc.
Efforts Needed to Save Oceans…#4
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Promoting
sustainable mining
practices
 Use
environmentally
friendly extraction
processes so to limit
sea floor disruption.
Efforts Needed to Save Oceans…#5
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Educating people
 Educate
people to see oceans not as a
frontier to exploit, but as a scientific frontier
to explore and use carefully
Efforts Needed to Save Oceans…#6
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Entering into international agreements
 Whose
goals are to cooperatively save our
oceans!
 Marpol Treaty  marine pollution (ex:
plastic trash)