you are likely to find Marine in/at/on Ocean. Ocean is the opposite of Desert. Desert is related to Valley. Valley is related to Echo. 
Site is related to Area. Area is related to Back. 
Marine --AtLocation--> Ocean <--Antonym--> Desert <--RelatedTo--> Valley <--RelatedTo--> Echo 
Site <--RelatedTo--> Area <--RelatedTo--> Back 