More than 70% of the surface of the Earth is covered with seawater, which has a huge influence on life on our planet. Oceans play an important role in communication, whether via ship, cable, pipeline or air traffic, and are reservoirs of natural resources. Yet the potential of the sea is largely untapped and even unexplored, partly because of the logistical difficulties and the specialist equipment needed to reach all areas (Fig. 1). Reserves of gas and oil have not been fully identified, and we have not yet begun to exploit alternative energy sources, such as thermal, wind, wave or tidal energy, significantly, let alone the mineral stores beneth the sea bed.
Oceans also play a central role in scientific research, whether it is focused on economic endpoints or on understanding the natural world through questions of climatology, palaeoclimatology, biology or geophysics. The seas play an important role in global weather patterns: oceanic currents, such as the Gulf Stream, influence the global climate and affect the climatological features of different regions. The oceans are themselves influenced by climate change: ice melting in the Arctic and its influence on the Arctic Ocean is one example.
The world’s oceans are also deeply affected by global economic and demographic developments. Technical advances and explosive population growth in the past century have led to an increased consumption of marine resources. Use of the oceans for wind farms or waste disposal have created conflicts. The overexploitation of resources, pollution of the seas and climate change have damaged marine resources, leading to drastically reduced fish stocks and even the extinction of some species of marine life, as well as ecological damage to the marine environment.