Marine life appeared in the form of fish, which live exclusively in water. Some of these evolved into amphibians which spend portions of their lives in water and portions on land. Other fish evolved into land mammals and subsequently returned to the ocean as seals, dolphins or whales. Plant forms such as kelp and algae grow in the water and are the basis for some underwater ecosystems. Plankton, and particularly phytoplankton, are key primary producers forming the general foundation of the ocean food chain. Marine invertebrates exhibit a wide range of modifications to survive in poorly oxygenated waters including breathing tubes (see
Short food supply chains can develop autonomous marketing strategies based on differentiation. These strategies give farmers the possibility of keeping a bigger share of the value added within the farm and within the local economies. Given these characteristics, short food supply chains are increasingly taken into consideration by rural and food policies as a driver of change in the food system and a policy tool for rural development. The analysis of short food supply chains has fed a broader debate on "alternative food chains", "alternative food networks", and "sustainable food chains". SFSCs are considered the most appropriate channels for organic and locally specific products