Strange marine life's origin in one sort of water (7)
I believe the answer is:
mineral
'one sort of water' is the definition.
'strange marine life's origin' is the wordplay.
'strange' indicates anagramming the letters.
'origin' indicates taking the first letters.
The initial letter of 'lifes' is 'l'.
'marine' is an anagram of 'minera'.
'minera'+'l'='MINERAL'
'in' acts as a link.
(Other definitions for mineral that I've seen before include "Ore; soft drink" , "Metal ore" , "Made from inorganic matter" , "E.g. bauxite, quartz" , "Neither animal nor vegetable" .)