Oceans and the Blue Economy

In the run up to the Malta Commonwealth Heads of Government Meeting 2015 CHEC is to publish a special issue of its Journal on Water Security. In this background article Eva Ekehorn, CHEC's Hon. Secretary, discusses some of the major challenges that face the world's oceans.
Introduction
The oceans are vast, enormous and appear to go on for ever.  Water covers 70% of the Earth’s surface and to call it the Blue Planet would seem apt. Whilst humans have lived by and traversed the oceans for centuries, our knowledge about life and chemistry in the oceans is still limited.  The deep sea, down to 11,000m in the deep trenches, is of course even less explored but with new technology, our knowledge of the oceans is slowly increasing.Oceans are an essential source of life. The oceans contain 97% of all water and act as the ‘reversed lungs’ of the Earth’s water cycle through the evaporation of water into the atmosphere and its subsequent falling on land where it provides living creatures with drinking water.  The oceans provide us with half the oxygen we breathe.  They also act as a buffer on temperature fluctuations and regulate the climate.  The oceans are all connected and water moves constantly, with surface water sinking at turning points and continuing to flow in the depths of the sea.So will this seemingly unlimited source of sustainable ecologies be able to cope with the stresses from of an industrial world inhabited by 8 to 9 billion human beings?  Well, it appears that it cannot.  There are many ways human populations have an impact on the water, its chemistry and its organic life.  We have done so for a long time, but are now becoming more aware that the ocean is not infinitely resilient to human encroachment.  This paper is an attempt to highlight the interaction between humans and the ocean and the consequences of this interaction.
Long term changes in the oceans
The oceans absorb 30% of the CO2 from human activities.  Over millennia the rate of absorption has changed, due to shifting continents and long term changes in the Earth’s climate, but it is now accelerating due to the burning of fossil fuels and the consequent increase in CO2 in the atmosphere.   The oceans are becoming increasingly more acidic, dissolving calcium that creatures require.  Many crabs and crustaceans depend upon it to build protective shields, and coral reefs require calcium for their construction. A lack of calcium could subtly but significantly damage the ability of life to thrive on the sea-bed.However, this is not the only threat to the oceans and its living organisms.In 2003 the UN specialised agency International Maritime Organisation (IMO) defined four major threats to the ocean and the marine life.  They were, not necessarily in this order of importance: 1) aquatic invasive organisms in ballast water; 2) land-based sources of marine pollution; 3) over-exploitation of living marine resources and 4) physical alteration of coastal and marine habitat.Humans have always lived along the Earth’s waters.  They have used materials from timber trunks to reed floats to go exploring, to fish or to trade.  The differential impact of today’s huge steel container ships, however, is potentially irrevocable. In the contemporary ‘Anthropocene’ period, the human-ecological relation between humans and nature is defined by the often unseen damage that industrial technologies cause beneath the surface of the oceans.