The ocean is still an undiscovered world, yet it accounts for 90% of the biosphere, covers 71% of the earth's surface, absorbs 50% of greenhouse gas emissions and provides more than 50% of the oxygen we breathe. It is also a source of sustenance and development for human civilisation, as long as its balance is not compromised. Issue 45 of Renewable Matter is a voyage into the complicated relationship between man and the sea, following the route of an increasingly sustainable blue economy.