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 proximate, extended. Face to face are characterized by physical encounters between producers and consumers (as in the case of farmers' markets). In the proximate short food supply chains producers are not necessarily managing product distribution (as in the case of consumers' cooperatives). In the extended short food supply chains, although geographical distances between producers and consumers may be long, consumers are aware of the identity of the producers and of the products (such as in the case of fair trade and protected denominations of origin). An action plan developed in 2009 at the Ministry of Agriculture, Agrifood, and Forestry of