oceans on the edge

Geography - oceans on the edge

human activity - marine ecosystems

• - pollution and waste disposal (oil spills and dumping rubbish)
• this cause eutrophication. for example nitrate fertilisers cause algae blooms, which uses up all the oxygen and species suffocate.
• - overfishing
• there is an unsustainable supply of fish to reach the increasing demand. for example, overfishing of tuna can decrease shark numbers but increase mackerel.
• - siltation
• plants near the coast get buried in silt from soil which has washed into the sea. plants can't reach sunlight so they die
• - global warming
• sea temperature rise causes extinction of marine species that can't adapt to higher temperatures
• sea level rise causes to drowning of vegetation
• increased acidification of seawater (carbon dioxide)
• bleaching of coral reefs

Firth of Clyde, near Glasgow, Scotland

• conflicts
• government 'no-take' zone policy:
• - increased fish, seals and porpoises
• - increased tourism
• -fishermen have lost jobs
• increased tourism:
• -boosts local economy
• -disrupts wildlife
• oil and gas exploration:
• -provides jobs
• -increased pollution and spoils landscapes
• Pressures
• - overfishing:
• firth of clyde is completely overfished e.g Lamlash bay overfished for scollops
• - sewage disposal:
• laws have stopped sewage disposal of sewage from homes directly into the sea
• - tourism:
• yachting, kayaking and diving are popular activities along the coastline but they disturb wildlife
• - military testing:
• Firth of Clyde is used as a nuclear submarine testing ground

protection of marine ecosystems

• The North Sea
• Greenpeace (a conservation charity) want to introduce marine reserves to reduce over-fishing
• the North Sea was polluted but now governments make industries filter out pollutants and treat sewage.
• the reasons for overfishing in the North Sea are; bigger and faster boats, bigger nets, technology like sonar to track movement of the fish, higher demand
• the EU set quotas every year, however fishermen then aim to catch their whole quota
• a whole-ecosystem approach would benefit the North Sea
• The law of the sea
• no single nations can exploit ocean resources
• there is a treaty that created 4 zones of increasing sizes to give different levels of protection and ownership. for example; territorial seas, exclusive economic zones.
• these zones encourage nations to protect and conserve parts of the ocean closest to them.