Oceans on the Edge Revision

8/13/2019 Oceans on the Edge Revision

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Revision Notes


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What you need to know1. Threats to the ocean

2. Ecosystem change

3. Increasing exploitation4. Sustainable management


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How and why are some ecosystemsthreatened with destruction?

The term ecosystem describes a grouping of plants and

animals that is linked with its local physical environment. The oceans, covering two-thirds of our planet, are home

to marine ecosystem communities composed of fish,aquatic plants and sea birds- as well as tiny but veryimportant organisms such as krill and plankton.

HINT: make sure you are able to name some values of theOceans e.g. its uses and value to human and animal life.


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Unsustainable Uses The way we use Oceans is becoming UNSUSTAINABLE thismeans we aren't treating/using it in a way that will preserve itfor future generations. Within the oceans here is a naturalbalance between all life- these relationships form the FOOD

WEB. It is also important to consider the NUTRIENT CYCLE which

is the movement and re-use of important substances e.g.,nitrogen.

DISRUPTIONS TO FOOD WEBS the main three disruptions

you need to understand are:1. Overfishing2. Eutrophication (caused by pollution)3. Siltation (sedimentation)


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Climate Change Climate change also disrupts the oceans.

Warmer Water

Fish in tropical seas could facefamine

Food shortages then develop

throughout entire food webs

More acidic water andbleaching

Carbon dioxide dissolves in water toform carbonic acid

Small rises in acidity can seriouslydamage coral reefs, which thenappear bleached after losing their

vibrant colour

Higher Sea Levels

Melting ice sheets on land masseswill bring sea-level rises

Coastal marine ecosystems such as

mangrove swamp or UK salt marsheswould become permanentlysubmerged and unique maritimecommunities might disappearaltogether


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How should ecosystems be managed

sustainably? There are three ways that marine ecosystems can be

managed and that is again, as with the other units, at a

LOCAL, REGIONAL and GLOBAL SCALE.


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Local Scale Managing coral reefs: Reefs are made of living animals, each piece contains polyp.

They are part of a large colony of marine life. The polyp are

skeletal creatures that form coral in clear, warm andsunlight seas.

Coral reefs are home to of the worlds fish species. It alsoacts as natural barriers that protect the coastline fromerosion. They are also great for tourism. However there aresustainability issues that come with this.

Your case studies are the Great Barrier Reef, the Coral

Triangle, and the Soufriere Marine Management Area


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Coral Reefs Under Threat


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The location of the SMMA, which stands for the Soufriere

Marine Management Area is located in the town of Soufrierein the west coast of the Caribbean island of St.Lucia. The SMMA was formed in 1992 to protect the marine wildlife

and reefs immediately surrounding the town. It brought together the following people, who would normally

come into conflict: The local town council

Local hotel owners Water-taxi owners Dive businesses Fishermen Marine managers

Overall the SMMA has been successful as a model of

sustainability. As a result, some of the best dive sites in the Caribbean are

found in the waters of the SMMA.Result:Some problems the area has become so popular that the marine environment is threatened by mass tourism rapid development in Soufriere encourages siltation and pollutionBut also positives the numbers, sizes and diversity of fish species has increased many stakeholders are now involved in marine conservation


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Regional Scale: Managing the

North Sea

Such as:1. ensuring that the mesh of nets wont catch

undersized young fish2. limiting the number of hours and days that fishing

boats can operate each year3. quota management4. discard management5. setting up marine reserves which protect all species

6. further research into how fishing affects the wholeecosystem

1. The EU Common Fisheries Policy hastried to bring back fish stocks fromcatastrophically low levels in the NorthSea.

2. Fishermen want as large a quota aspossible but marine scientists argue thatonly no fishing marine reserves will savespecies like the cod. But this is expensiveas it means you have topay fishermennot to fish!

3. Additionally, global warming is playing a

part. Cold water species of planktonhave been replaced by warm waterspecies, changing the food available forbaby cod. Furthermore, as the North Seawarms, cod will migrate to Arctic areas.


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Global Scale Global actions are needed to tackle pollution and to

save threatened species from overfishing andextinction. International Organisations play a largerole in ensuring that the oceans are protected.

The United Nations Food and AgricultureOrganisations regulates the management of deep seafisheries. Other examples include IWC, UNCLOS andCITES (see next slide for more details)

Individuals around the world can also do their bit bychanging their shopping habits to ensure that we onlybuy sustainably sources fish and buy dolphin friendlytuna. (Think about what came out of your work onyour DVDs)


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IWC: The International Whaling Convention wasestablished in 1946 to oversee the management of the

whaling industry worldwide. In 1986 it issued anindefinite ban on commercial whale hunting.

UNCLOS: The United Nations Convention on the Law

of the Sea addresses the main sources of oceanpollution land based/coastal activities; continentalshelf drilling for gas and oil; seabed mining; ocean

dumping; and pollution from ships.

CITES: The Convention on International Trade inEndangered Species of Wild Fauna and Flora givesglobal protection to all of the great whales


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Far More Difficult Problems To tackle on a global scale is the growth of the PacificGarbage Patches.

These are enormous rubbish-strewn regions of the

north Pacific. The currents flow creates giant pools ofrubbish soup.


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Practice Questions

1. Using examples, describe the threats facing marine ecosystems(6) Foundation

2. Using named examples, explain the short and long-term threatsfacing marine ecosystems (6) Higher

3. Describe the type of area a coral reef might be found (2)

4. How can an undisturbed coral reef support human activities?(2)

5. How could an increase in demand for one type of fish impact onthe food chain? (6)

6. Explain how the change in oceans currents could impactmarine ecosystems? (6)

7. Explain why the worlds oceans are under threat (4)

8. With reference to an example, explain the problems and

successes of sustainable fishing (4)

Documents

Oceans on the Edge Revision