Plant
Algae comprise several different groups of organisms which produce food by photosynthesis and thus have traditionally been included in the plant kingdom. The seaweeds range from large multicellular algae to single-celled organisms and are classified into three groups, the brown, red and green algae. There is good evidence that the brown algae evolved independently from the others, from non-photosynthetic ancestors that formed endosymbiotic relationships with red algae rather than from cyanobacteria, and they are no longer classified as plants as defined here.
Ocean storage of carbon dioxide
In order to mitigate global warming, seaweed farming is both a possible and plausible way. This method was adopted in early ocean algae proposals to mitigate global warming. This is done through commercial kelp farms designed to take up tens of thousands of square kilometres of the open ocean. Through this method, seaweed beds will perform as an effective sinks by decreasing the level of dissolved inorganic carbon (DIC) in the ocean.
Seaweeds do the above by removing carbon through the process of photosynthesis, taking in excess CO2 and producing O2. Facts and figures have shown that 0.7 million tonnes of carbon are removed from the sea each year by commercially harvested seaweeds. Even though seaweed biomass is small as compared to the coastal region. They remain essential due to their biotic components, the ability to provide valuable ecosystem services and high primary productivity. Seaweeds are different from mangroves and seagrasses, they are photosynthetic algal organisms and non-flowering. Even so, they are primary producers that grows in the same way as their terrestrial counterparts, both of which assimilate carbon by the process of photosynthesis and generates new biomass by taking up phosphorus, nitrogen, and other minerals.