In Asia Porphyra (nori) is marketed and sold as a seaweed eaten whole either dried or in soups, or as a tasty wrapping for sushi and rice. standing of that environment as a whole. The oceans cover roughly 71% of the Earth's surface and contain 97% of the Earth's water. Not surprisingly, the oceans are the largest source of biotic diversity on the planet. It is estimated that as much as 80% of all life on Earth is found under the ocean surface and an estimated 90% of all photosynthetic life occurs in the oceans. This means that seaweeds and the microscopic algae of the oceans make up roughly nine tenths of all the plant-like life on Earth. Kelp have a number of economic, medicinal and nutritional values. In Japanese culture, agar from red seaweeds is used to bind confectionery products. Did you know these 10 facts about seaweeds? Most of the world’s oxygen (about 70%) comes from seaweeds and other microscopic algae. Seaweeds support primary production levels that are 6-10 times greater that the most intensive land-based agricultural systems. It is estimated that there are nine times more microscopic algae and seaweeds in the oceans than there are plants on land. Species from the genus Porphyra make up at least 80% of all seaweed harvested across the world.