Free images results:

Seaweed pictures, stock photos and images


Harbour Royalty Free Stock Photo
Author: Monkie
Reef roof Stock Images
Author: Duey
Seaside Stock Photography
Author: Abdone
Uniqueness Royalty Free Stock Photography
Author: Lisafx
Lost Stock Images
Author: Gummy231
Cruise 1 Stock Image
Author: Scottman
Seaside Stock Image
Author: Abdone
Sea life Royalty Free Stock Image
Author: Synnous

Also, here are some commercial RF-licensed images that match your search criteria:  
Seaweed Stock Photos
Author: Maigi
Seaweed Royalty Free Stock Photo
Author: Davinci