c. 30 species; see text
Laminaria is a genus of 31 species of brown algae commonly called "kelp". Some species are also referred to as tangle. This economically important genus is characterized by long, leathery laminae and relatively large size. Some species are referred to by the common name Devil's apron, due to their shape, or sea colander, due to the perforations present on the lamina. It is found in the north Atlantic Ocean and the northern Pacific Ocean at depths from 8 to 30 m (26 to 98 ft) (exceptionally to 120 m (390 ft) in the warmer waters of the Mediterranean Sea and off Brazil). Laminaria form a habitat for many fish and invertebrates. 
The life cycle of Laminaria has heteromorphic alternation of generations which differs from Fucus. At meiosis the male and female zoospores are produced separate then germinate into male and female gametophytes. The female egg matures in the oogonium until the male sperm fertilizes it. Life-Cycle: The most apparent form of Laminaria is its sporophyte phase, a structure composed of the holdfast, the stipe, and the blades. While it spends its time predominately in the sporophyte phase, it alternates between the sporophyte and its microscopic gametophyte phase.
Laminaria arrived in China from Hokkaido, Japan in the late 1920s. Once in China, Laminaria was cultivated on a much larger industrial scale. The rocky shores at Dalian, the northern coast of the Yellow Sea, along with the cold waters provided excellent growing conditions for these species. Laminaria was harvested for food and 1949 yielded 40.3 metric tons of dry weight. Laminaria need cold water to survive and can only live 36° N latitude. With summer the heat difference in the summer, some of the southern plants quickly die due to increased temperatures.
In 1949, the Chinese started to commercially grow laminaria as a crop. This increased the production of dry weight to 6,200 metric tons. Farming laminaria is still a large production for China. However, after the 1980s production drop due to new technology in mariculture.
Laminaria is generally farmed using the floating raft method in which young laminaria sporophytes are attached to submerged ropes. These ropes are then attached to floating rafts.
Laminaria is found in colder ocean waters, such as arctic regions. Preferring to stay in regions where there are rocky shores, this allows the laminaria to attach. Due to the height of the Laminaria, they provide protection for creatures that the open ocean does not often give. Invertebrates are just one of the organisms that live among the algae. Sea snails and other invertebrates feed on the blades (leaves) of the laminaria. Other organisms like sea urchins feed on the holdfasts which end up killing the algae. red sea urchins, found on the North America Pacific Coast, can decimate kelp, like Laminaria, if the urchins are not managed by sea otters.
Laminaria expresses a haplo-diplophasic life history in which it alternates from a macroscopic thallic sporophyte structure, consisting of the holdfast, a stipe, and the blades, to a filamentous, microscopic gametophyte. The sporophyte structure of laminaria can grow to 7 metres (23 ft), which is large in comparison to other algae, but still smaller than the giant kelps such as Macrocystis and Nereocystic that can grow up to 40–50 metres (130–160 ft). The gametophyte structure, however is no more than a few millimeters in length. In opposition to the gametophyte phase, which only consists of one type of tissue, the more complex sporophyte phase is made up of different types of tissue. One of these tissues includes a sieve-like element which translocates photassimilates(Schmitz 1982). These structures are very similar to mesophyll cells found in higher plant leaves.
A laminaria stick may be used to slowly dilate the cervix to induce labor and delivery, or for surgical procedures including abortions or to facilitate the placement of an Intrauterine Device. The stick is made up of a bundle of dried and compressed laminaria that expands as water is absorbed.
Certain carbohydrates such as mannitol, laminarin, and alginate can be extracted from laminaria. Mannitol is used to decrease high pressure in the eyes, and to lower excessive intracranial pressure. Laminarin has two forms, soluble and unsoluble. The soluble form of Laminarin has high antitumor activity, can be used in the treatment of antibiotic-resistant nosocomal infections, can aid in normalizing enteric metabolisms, helps to improve enzymatic processes of the intestine and does not possess antigenic or pyrogenic properties. Laminarin continues to be of active study in today’s medical field.
Various species of Laminaria have been used for food purposes since ancient times wherever humans have encountered them. Typically, the prepared parts, usually the blade, are consumed either immediately after boiling in broth or water, or consumed after drying, or drying then re-hydrating. The greater proportion of commercial cultivation is for algin, iodine, and mannitol, which are used in a range of industrial applications. In South Korea it is processed into a sweetmeat known as Laminaria jelly, in other countries it is also used in fresh salad form, which is also canned for preservation for deliverу and selling purposes in other regions. Many countries produce and consume laminaria products, but the largest is China.
Due to their ability to grow underwater and in salt water, algae is being looked into as a source of biofuel. Laminaria is one of the five macroalgaes farmed for products such as food. Those five genera contribute to 76% of the total tonnage for farmed macroalgae. Laminaria is less desired due to the high ash content when burned. Laminaria has an ash content of 33% while wood has about a 2% ash content when burned. The large amount of ash can be problematic for efficiency of the boilers. Algae have a large water content which requires a large about of energy to dry the algae out before being able to properly use it.
More research is being done with anaerobic digestion, which is the most promising practice to extract energy from Laminaria. There are still issues with moving forward with anaerobic digestion, such as cost. 
The ability of laminaria along with other brown algae to absorb heavy metals is a current area of interest in terms of potentially using them to remove heavy metals from wastewater. Laminaria has been shown by recent research to have a favorable M/G ratio for heavy metal absorption in its alginate. This M/G ratio is the ratio between the L-gluronate (G) and D-mannuronate (M) in the alginate, a natural anionic polymer that is found in all brown algae. This alginate is able to form a gel that contains carboxyl groups that can bind heavy metal cations such as Cu2+
, and Pb2+
, thereby allowing these metals to be removed from wastewater.
- Laminaria abyssalis A.B. Joly & E.C. Oliveira – South American Atlantic
- Laminaria agardhii Kjellman – North American Atlantic 
- Laminaria appressirhiza J. E. Petrov & V. B. Vozzhinskaya 
- Laminaria brasiliensis A. B. Loly & E. C. Oliveira
- Laminaria brongardiana Postels & Ruprecht 
- Laminaria bulbosa J. V. Lamouroux
- Laminaria bullata Kjellman
- Laminaria complanata (Setchell & N. L. Garder) Muenscher
- Laminaria digitata (Hudson) J. V. Lamouroux
- Laminaria ephemera Setchell – Pacific of North America: From Vancouver to California 
- Laminaria farlowii Setchell – Coast of the North American Pacific 
- Laminaria groenlandica – British Columbia
- Laminaria hyperborea (Gunnerus) Foslie – Northeast Atlantic, Baltic Sea and North Sea.
- Laminaria inclinatorhiza J. Petrov & V. Vozzhinskaya
- Laminaria multiplicata J. Petrov & M. Suchovejeva
- Laminaria nigripes J. Agardh
- Laminaria ochroleuca Bachelot de la Pylaie
- Laminaria pallida Greville – South Africa,  Indian Ocean, Canary Islands and de Tristán da Cunha 
- Laminaria platymeris Bachelot de la Pylaie
- Laminaria rodriguezii Barnet
- Laminaria ruprechtii (Areschoug) Setchell
- Laminaria sachalinensis (Miyabe) Miyabe
- Laminaria setchellii P. C. Silva
- Laminaria sinclairii (Harvey ex J. D. Hooker & Harvey) Farlow, Anderson & Eaton – North American Pacific coast 
- Laminaria solidungula J. Agardh
- Laminaria yezoensis Miyabe
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