Pollution
Occurs when human activity adds a substance to the environment that affects organisms
adversely and at a greater rate than at which it can be rendered harmless.
Point source = release of pollutants from a single, clearly identifiable source
Non-point source = release of pollutants from several, dispersed sources
UNESCO Decade of Ocean Science for Sustainable Development:
Aims to reduce threat to oceans by Sustainable Development Goal 14, 2015 (SDG14).
Integrates a range of partners and stakeholders – International Maritime Organisation
(IMO), NGO, Government, Food and Agricultural Organisation (FAO)
Forms of pollution
Burning fossil fuels:
CO2, SO2, nitrogen oxides + particulates
• 100,000 ocean cargo vessels operate 24 hours / day and 280 days / year
Powered by bunker fuel high in pollutants
• 9% SO2 and 20% NO2 emissions annually; 4% all anthropogenic emissions
• Concentrated along busiest international shipping routes in N.hemisphere + major
ports (San Francisco). Popular cruise destinations (Caribbean and Alaska); restricted
coastal inlets create haze of diesel fumes
• ‘slow steaming’ = reducing speed; significant fuel savings
• Better ship design (efficient hulls + propeller shapes)
• Scrubber units remove 99% emissions, cost $2 million each
• Shipping air-pollution limits only established in 2005
Industrial pollution
• River discharge / washed out of atmosphere by precipitation. Waste dumping;
radioactive water from Sellafield into Irish sea
• Used to remove raw sewage and industrial effluent in LIDCs extremely toxic,
harmful to human health and ecosystems. Environment compromised in
development.
Radioactive waste:
• Industry increases post WW2 in Europe, China + USA for energy, medicine, industry
+ nuclear weapons
• 1946-1993 13 countries disposed into oceans. 10,000s radioactive steel drums + 8
nuclear submarines sunk (corrosive sea water causes release)
• Fukushima, Japan 2011 tsunami
Government bans on catching/consumption of fish/shellfish due to radiation accumulation
in food chains.
Air-borne radiation carried to NW USA
Oceanographers believe serious threat only local scale
Pollutants + algal blooms
Development:
1. Nutrients leached into sea (phosphates + nitrates)
2. Rapid algae growth → algal bloom
3. Algae cover sea surface, prevent light reaching lower water column
4. Bacteria feed on dead algae biomass
5. Aerobic respiration of decomposers removes dissolved O2
6. Decreased O2 concentration impacts other organisms
Nutrient sources:
Organic waste, detergents, pesticides, agricultural growth hormones
Impacts:
• Local fishing industry → fish decrease, catch not economically viable
• Local tourist industry → water appears green
• Human health → fish consumption limited, increased water treatment costs
Case study – Deepwater Horizon 2010
