12 marks: Coasts

1. How can one coastal landscape provide a strong barrier against disease diffusion?

• Coastlines = physical barrier to diffusion.

• Coastal flooding/tsunamis - exacerbate threat of disease.

• Tombolos make islands accessible for disease diffusion.

• Salt marshes - breeding ground for disease (stagnant water).

• Human activity - contaminate sea water e.g. oil spills increases rates of disease. (contaminated)

Example?

Low lying countries e.g. Bangladesh have problems with stagnant water & dense populations increase spread of infectious disease.

2. How can rising sea levels on coasts increase spread of disease?

• Rising sea levels - flooding of delta areas & increase spread of disease.

• Flooding: contaminate drinking supplies/sanitation.

• E.g. 2020 Bangladesh river flood, led to spread of diarrhoea & water-born diseases.

Another example?

• Hurricane Katrina

• Coastal flooding cause by storms cause stagnant water to be present.

• Breeding grounds for mosquitos that are vectors for West Nile Virus.

• Led to increase in infectious, communicable diseases in coastal regions - worse as climate change progresses.

3. How can physical factors on coasts lead to spread of disease?

• Increased water temps on coasts - algal blooms.

• Warmer waters encourage algal blooms - release toxins that are harmful to sea life & humans e.g. red rides in Hawaii.

• Consumption of toxins (water or fish) can lead to diarrhoea - spread amongst communities not dealt with.

4. How can ocean currents alter temps, impacting prevalence of diseases?

• Warmer ocean currents - warm air above it leading to warmer air temps & increased humidity.

• Favourable physical conditions for tropical diseases to increase e.g. malaria.

Cold ocean currents?

• Create drier conditions & cold air temps = reduce physical conditions for tropical diseases e.g. malaria & west nile virus.

• But could help encourage spread of influenza - more efficient at lower temps.

• Thus, ocean currents dictate air temps & humidity, causing physical conditions for tropical diseases.

5. How can coastal winds and waves lead to spread of diseases?

• Coastal winds can blow sources of pollution out to sea e.g. air pollution.

• Thus, coastal winds can reduce formation of non-communicable diseases e.g. lung cancer by removing the source of pollution from area.

• Or pushing it into a new area & causing high concentrations.

Economic activity?

• Economic activity & management - increase spread of disease.

• Sand mining (Mangawhai Pakiri) can cause coastal retreat due to increased erosion - increases chance of coastal flooding.

• Increases chance of flooding - can cause stagnant pools of water for vectors, & contamination of water-sewage source = water-borne diseases.