Exploring Oceans

The use of oceans as escape routes for migrants

Types of migration International Monetary Fund (IMF) defines globalisation as ‘the growing economic interdependence of countries worldwide through increasing volume and variety of crossborder transactions in goods and services, freer international capital flows, and...

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Oceans present hazardous obstacles to human activities

Piracy: The act of boarding any vessel with intent to commit theft or any other crime, and with intent or capacity to use force in furtherance of this. Hot spots: Somalia, Indonesia and Nigeria Vulnerable route through Gulf of Aden and Red Sea, the Malacca and...

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Climate change is altering high latitude oceans

60 degrees North or South Formation of sea ice: 1. In the high latitudes more heat leaves the system than is inputted creating annual net deficit in heat budget. 2. Deficit occurs because the sun’s rays hit the surface at a low angle meaning less energy is spread over...

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Climate change is altering sea levels

Monitored by Intergovernmental Panel on Climate Change (IPCC). Eustatic sea level change is increasing, currently 3.00mm per year. If all ice fields melted sea level would rise 70m. Causes • Thermal expansion of water Global warming increases surface temperatures and...

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Climate change and the ocean system

Ocean acidification 30% anthropogenic CO2 produced in the last 250 yrs has been absorbed in the ocean sink. Rising temperature reduces ability to absorb. Tipping point = the critical threshold which leads to irreversible change if passed Average global surface ocean...

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Ocean currents disperse / concentrate pollution

Ocean circulation Marine debris from fluvial discharge, ship dumping and accidental discard. Global pollution: • ¾ UK beaches polluted with nurdles • Fishery equipment and ropes; breakdown forms microplastics • Most polluted place – Henderson Island, 17,000 tonnes...

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The world’s oceans are a distinctive feature of the Earth

The global distribution of the world’s oceans: The relief of ocean basins: Water deepens along continental shelf. Slope angle increases at continental slope. Wide, gently sloping continental rise. Flattest and deepest section abyssal plain which includes seamounts...

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Water in the world’s oceans varies

Horizontal and vertical changes in salinity and temperature: Salinity = A measure of the concentration of salt (NaCl). Measured as g per 1000g water (ppt) by NASA’s Aquarius Satellite. Freshwater - <0.5ppt Seawater – 35ppt Salinity is lowest in the surface zone and...

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The biodiversity of oceans

Factors affecting oceanic ecosystems: Net Primary Productivity (NPP) = the amount of carbon fixed by photosynthesis that exceeds respiration demands of the plant and goes into growth. Light Most intense over the equator. With increasing distance from the equator,...

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