Possible Clues:

• Large leathery brown seaweed
• Aquatic source of iodine
• Sea urchin's snack
• Dashi ingredient
• Marine vegetation
• Large seaweeds with leathery fronds
• Marine growth rich in iodine
• From nickel, potential source of iodine
• Brown algae
• ___ Forest, place where Spongebob and Squidward probably go to do shrooms and sex stuff