KELP

Kelp are large brown algae or seaweeds that make up the order Laminariales. There are about 30 genera. Despite its appearance and use of photosynthesis in chloroplasts, kelp is not a plant but a stramenopile (a group containing many protists). Kelp grow from stalks close together in very dense areas like forests under shallow temperate and Arctic oceans. They were previously thought to have appeared in the Miocene, 5 to 23 million years ago based on fossils from California. Kelps were present in the northeastern Pacific Ocean by at least 32 million years ago. These organisms require nutrient-rich water with temperatures between 6 and 14 °C (43 and 57 °F). They are known for their fast growth —the genera Macrocystis and Nereocystis can grow as fast as half a metre a day (that is, about 20 inches a day), ultimately reaching 30 to 80 metres (100 to 260 ft). Through the 19th century, the word "kelp" was closely associated with seaweeds that could be burned to obtain soda ash (primarily sodium carbonate). The seaweeds used included species from both the orders Laminariales and Fucales. The word "kelp" was also used directly to refer to these processed ashes. Alaskan beach kelp The thallus (or body) consists of flat or leaf-like structures known as lamina (or blades) that originate from elongated stem-like structures, referred to as the stipes. A root-like structure (called the holdfast) anchors the kelp to the substrate of the ocean. Gas-filled bladders (pneumatocysts) form at the base of blades of American species, such as Nereocystis lueteana, to hold the kelp blades close to the surface to access light for photosynthesis.(Mert. & Post & Rupr.) The stipes are generally covered with a slimy mucilage layer, rather than a waxy cuticle. Growth occurs at the base of the meristem, where the blades and stipe meet. Growth may be limited by grazing. Sea urchins, for example, can reduce entire ecosystems to kelp-less wastelands known as urchin barrens. The kelp life cycle involves a diploid sporophyte and haploid gametophyte stage. The haploid phase begins when the mature organism releases many spores, which then germinate to become male or female gametophytes. Sexual reproduction then results in the beginning of the diploid sporophyte stage, which will develop into a mature individual.
https://www.youtube.com/watch?v=F3kyMtv-iIA
Kelp: Hidden Treasure of the Salish Sea | Changing Seas
https://www.youtube.com/watch?v=rCRncbD1X7g
Reviving Giants: A Journey into the Restoration of Tasmania’s Giant Kelp Forests
https://www.youtube.com/watch?v=LBgaRonO660
Our Kelp Forest Has Sprung to Life! - here’s how we did it