''Nereocystis'' (Greek, 'mermaid's bladder') is a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus of subtidal

kelp Kelps are large brown algae or seaweeds that make up the order (biology), order Laminariales. There are about 30 different genus, genera. Despite its appearance and use of photosynthesis in chloroplasts, kelp is technically not a plant but a str ...

containing the species ''Nereocystis luetkeana''. Some English names include edible kelp, bull kelp, bullwhip kelp, ribbon kelp, bladder wrack, and variations of these names. Due to the English name, bull kelp can be confused with southern bull kelps, which are found in the Southern Hemisphere. ''Nereocystis luetkeana'' forms thick beds on subtidal rocks, and is an important part of

kelp forest Kelp forests are underwater areas with a high density of kelp, which covers a large part of the world's coastlines. Smaller areas of anchored kelp are called kelp beds. They are recognized as one of the most productive and dynamic ecosystems on E ...

Etymology

The species ''Nereocystis luetkeana'' was named (as ''Fucus luetkeanus'') after the German-Russian explorer Fyodor Petrovich Litke (also spelled Lütke) by Mertens. The species was renamed in a description by Postels and Ruprecht.

Description

''Nereocystis'' is a brown macroalgae that derives chemical energy from

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

. ''Nereocystis'' in particular, similar to ''Pelagophycus porra'', can be identified by a single large pneumatocyst between the end of its hollow stipe and the blades.FOREMAN, R. E. (1970). ''Physiology, Ecology, And Development Of The Brown Alga, Nereocystis Luetkeana (mertens) P. & R'' (Order No. 7109813). Available from ProQuest Dissertations & Theses Global. (302503381). Individuals can grow to a maximum of . ''Nereocystis'' has a holdfast of about , and a single stipe, topped with a

pneumatocyst In phycology, a pneumatocyst is a floating structure that contains gas found on brown seaweed. A seaweed's thallus may have more than one. They provide buoyancy to lift the blades toward the surface, allowing them to receive more sunlight for p ...

containing

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

, from which sprout the numerous (about 30-64) blades. The blades may be up to long, and up to wide. It is usually annual, sometimes persisting up to 18 months. ''Nereocystis'' is the only kelp which will drop spore patches, so that the right concentration of spores lands near the parent's holdfast. The

thallus Thallus (: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. A thallus usually names the entir ...

of this common canopy-forming kelp has a richly branched holdfast ( haptera) and a cylindrical stipe 10–36 m (33–118 ft) long. The stipe terminates in a single, gas-filled pneumatocyst from which many blades grow. Each blade can grow up to 10 m (33 ft) long, and blade growth can reach 15 cm (5.9 in) per day. ''Nereocystis'' grows in areas where ''Pterygophora'' ''californica'' also inhabits. Bull kelp will often grow on the stipe of ''Pterygophora'', with up anywhere from 10 to 20 individuals of ''Nereocystis'' attaching to a single ''Pterygophora'' stipe.

Reproduction

Reproduction in ''Nereocystis'' is characterized by an

alternation of generations Alternation of generations (also known as metagenesis or heterogenesis) is the predominant type of life cycle in plants and algae. In plants both phases are multicellular: the haploid sexual phase – the gametophyte – alternates with a diploi ...

. The

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

generation is the recognizable macroscopic

sporophyte A sporophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the biological life cycle, life cycles of plants and algae. It is a diploid multicellular organism which produces asexual Spo ...

. During sexual reproduction, reproductive patches (sori) develop on the blades of the sporophyte and drop to the seafloor at maturity. The sori release haploid spores, which become the microscopic

gametophytes A gametophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has o ...

. The gametophytes produce

gametes A gamete ( ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. The name gamete was introduced by the Ge ...

, and if

fertilization Fertilisation or fertilization (see American and British English spelling differences#-ise, -ize (-isation, -ization), spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give ...

occurs, a new sporophyte organism may develop and begin to grow up from the seafloor.

Distribution

The species is common along the Pacific Coast of North America, from

Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...

to the

Aleutian Islands The Aleutian Islands ( ; ; , "land of the Aleuts"; possibly from the Chukchi language, Chukchi ''aliat'', or "island")—also called the Aleut Islands, Aleutic Islands, or, before Alaska Purchase, 1867, the Catherine Archipelago—are a chain ...

, Alaska. However, drift individuals disperse with ocean currents further south into northwest

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

, Mexico. Offshore beds can persist for one or many years, usually in deeper water than ''

Eualaria ''Eualaria'' is a monotypic genus of subtidal kelp containing the species ''Eualaria fistulosa''. Distribution and habitat It is native to the northern Pacific Ocean, where it ranges from the coast of Alaska and the Aleutian Islands to the Comma ...

'' or ''

Macrocystis ''Macrocystis'' is a monospecific genus of kelp (large brown algae) with all species now synonymous with ''Macrocystis pyrifera''. It is commonly known as giant kelp or bladder kelp. This genus contains the largest of all the Phaeophyceae or b ...

'', where they co-occur. This annual kelp grows on rock from the low intertidal to subtidal zones; it prefers semi-exposed habitats or high-current areas. It also does not grow in areas with breaking waves or swells. Its distribution is limited by the requirement of light for

, and preference for areas of high water movement where the microscopic gametophyte stage will not be covered by sediment. Other factors such as salinity,

turbidity Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of both water clarity and wa ...

and water temperature can affect ''Nereocystis'' distribution. ''Nereocystis'' tends to thrive in temperatures ranging from 5 to 20 degrees Celsius. It is rarely found in environments with high turbidity and low salinity. ''Nereocystis'' fails to thrive in areas of reduced salinity, such as brackish

estuarine An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...

waters, because it has difficulty adjusting to changes in salinity. The increased turbidity of such waters also decreases light available for photosynthesis, limiting its growth. Additionally, disease, competition, and herbivory can affect distribution.

Ecology

''Nereocystis'', like other large, canopy forming kelps, play a crucial role in maintaining the biologically diverse kelp forests in the temperate marine environments where they flourish. Its fast growth and size provide an important habitat not only for the fish and invertebrates that reside in kelp forests, but also for species that use kelp forests as foraging grounds. In bull kelp forests, kelp crabs are important grazers that control the ecosystem by feeding on large canopy kelps such as ''Nereocystis''.

Microbial communities

''Nereocystis'' fosters microbacteria species, affecting the ecology on a microscopic level. These microbial bacteria species foster the growth of seaweed, producing growth-promoting substances. According to studies by Weigel, the microbial communities that grow on ''Nereocystis'' are composed mostly of Proteobacteria, Bacteroidetes, Verrucomicrobia, and Planctomycetes. ''Nereocystis'' is unique in that it contains a large percentage of Verrucomicrobia, with it composing approximately 10% of microbacteria populations on ''Nereocystis''.

Human effects

Abalone mariculture (the commercial farming and harvest of

abalone Abalone ( or ; via Spanish , from Rumsen language, Rumsen ''aulón'') is a common name for any small to very large marine life, marine gastropod mollusc in the family (biology), family Haliotidae, which once contained six genera but now cont ...

) and an increasing demand in human consumption have led to a notable and marked increase in ''Nereocystis'' extraction. This extraction is done by hand and removes the top two meters of the forest. These first two meters contain bull kelp's pneumatocysts and its reproductive organs, so this method of extraction destroys kelp forests that depend on ''Nereocystis''.Hansen GI, Mumford TF (1995) 1994/1995 Regulations for Seaweed Harvesting on the West Coast of North America. Since bull kelp tend to only reproduce once a year, removal of these organs renders ''Nereocystis'' unable to reproduce.Springer, Yuri; Hays, Cynthia; Carr, Mark; Mackey, Megan; Bloeser, Jennifer (March 2007). "Ecology and Management of the Bull Kelp, Nereocystis Luetkeana" (PDF). The tissues of bull kelp are processed and turned into liquid fertilizer as well as food for abalones.

Human uses

''Nereocystis'' was not commercially harvested off the coast of California until around the 1980s. The beginning of this harvest is attributed to the Abalone International company, which was seeking mariculture expansion and efficiency. Kelp harvesters are legally mandated to record every aspect of their harvest, including but not limited to the amount of kelp, the species, and the location where it was taken from. Kelp is currently harvested from the Californian coast, Oregon, Washington, British Columbia, and Alaska. Human uses of ''Nereocystis'' include consumption and agriculture. It is pickled and eaten as a delicacy as well as used for creative purposes. In South Korea, ''Nereocystis'' used to make '' miyeok-guk'' (Korean kelp soup) weekly by new mothers as it's revered as a blood-cleanser. It is also customary to eat it on one's birthday.

References

External links

*
''Nereocystis luetkeana'' (K.Mertens) Postels & Ruprecht on Algaebase

{{Taxonbar, from=Q15156786, from2=Q3008573 Laminariaceae Flora of the Pacific Marine biota of North America Flora of Alaska Flora of California Flora of the West Coast of the United States Edible algae Laminariales genera Monotypic brown algae genera Flora without expected TNC conservation status Biota of the Temperate Northern Pacific