Possible Clues:

• Sailor and where he might be first obtaining preservative
• Chef's sprinkle, perhaps
• Gourmet cook's condiment
• Alternative to sodium chloride
• Ocean condiment
• With 8-Across, World records? * Natural seasoning
• Preservative for ocean-going sailor
• Gourmet condiment
• Content of oceans seen in new atlases
• It's left when ocean water evaporates