Oceans: A Very Short Introduction

The importance of the oceans to life on Earth cannot be overstated. Liquid water covers more than 70% of our planet's surface and, in past geological time, has spread over 85%. Life on Earth began in the oceans over 3.5 billion years ago and remained there for the great majority of that time. Today the seas still provide 99% of habitable living space, the largest repository of biomass, and holds the greatest number of undiscovered species on the planet. Our oceans
are vital for the regulation of climate, and with global warming and decreasing land area, they have become increasingly important as the source of food, energy in the form of oil and gas, and for their mineral wealth. Oceans also form a key part of the biogeochemical cycles of carbon, nitrogen, and
other elements critical to life. Nutrients in upwelling areas are spread by ocean currents, and the plankton of the seas supports a wealth of wildlife.