Short Notes:

Seaweed is the name for algae that live in sea water. Like most land plants, seaweeds create energy through photosynthesis. The raw materials for this process are readily available: Water is absorbed directly into the seaweed, along with the carbon dioxide that is dissolved in the water. The sun's rays that penetrate the water's surface provide enough light to catalyse the reaction.

Seaweed's watery environment adds an unusual aspect to photosynthesis. When sunlight passes through air, all seven of its component colours - red, orange, yellow, green, blue, indigo, and violet - travel in unison. But in water, some components pass through more easily than others. For this reason, many seaweeds have evolved with "auxilliary pigments" that aid in the absorption of specific components of sunlight, making photosynthesis more efficient.