Nereocystis | |
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Nereocystis luetkeana at Caspar Point, California | |
Scientific classification | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | SAR |
Clade: | Stramenopiles |
Phylum: | Gyrista |
Subphylum: | Ochrophytina |
Class: | Phaeophyceae |
Order: | Laminariales |
Family: | Laminariaceae |
Genus: | Nereocystis Postels & Ruprecht |
Species: | N. luetkeana |
Binomial name | |
Nereocystis luetkeana (K.Mertens) Postels & Ruprecht | |
Nereocystis (Greek, 'mermaid's bladder') is a monotypic genus of subtidal kelp containing the species Nereocystis luetkeana. [1] Some English names include edible kelp, bull kelp, bullwhip kelp, ribbon kelp, bladder wrack, and variations of these names. [2] Due to the English name, bull kelp can be confused with southern bull kelps, which are found in the Southern Hemisphere. [3] [4] Nereocystis luetkeana forms thick beds on subtidal rocks, and is an important part of kelp forests.
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. [5]
Nereocystis is a brown macroalgae that derives chemical energy from photosynthesis. 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. [6] Individuals can grow to a maximum of 36 m (118 ft). [7] Nereocystis has a holdfast of about 40 cm (16 in), and a single stipe, topped with a pneumatocyst containing carbon monoxide, from which sprout the numerous (about 30-64) blades. The blades may be up to 4 m (13 ft) long, and up to 15 cm (5.9 in) 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 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 Pterygophoracalifornica 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. [6]
Reproduction in Nereocystis is characterized by an alternation of generations. [7] The diploid generation is the recognizable macroscopic sporophyte. During sexual reproduction, reproductive patches (sori) develop on the blades of the sporophyte and drop to the seafloor at maturity. [8] The sori release haploid spores, which become the microscopic gametophytes. The gametophytes produce gametes, and if fertilization occurs, a new sporophyte organism may develop and begin to grow up from the seafloor. [9]
The species is common along the Pacific Coast of North America, from Southern California to the Aleutian Islands, Alaska. [10] However, drift individuals disperse with ocean currents further south into northwest Baja California, Mexico. [11] Offshore beds can persist for one or many years, usually in deeper water than Eualaria or Macrocystis , 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. [6] Its distribution is limited by the requirement of light for photosynthesis, and preference for areas of high water movement where the microscopic gametophyte stage will not be covered by sediment. [12]
Other factors such as salinity, turbidity and water temperature can affect Nereocystis distribution. Nereocystis tends to thrive in temperatures ranging from 5 to 20 degrees Celsius. [13] It is rarely found in environments with high turbidity and low salinity. [10] Nereocystis fails to thrive in areas of reduced salinity, such as brackish estuarine 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.
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. [14] 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. [15] In bull kelp forests, kelp crabs are important grazers that control the ecosystem by feeding on large canopy kelps such as Nereocystis. [16]
Nereocystis fosters microbacteria species, affecting the ecology on a microscopic level. These microbial bacteria species foster the growth of seaweed, producing growth-promoting substances. [17] 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. [18]
Abalone mariculture (the commercial farming and harvest of abalone) 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. [19] Since bull kelp tend to only reproduce once a year, removal of these organs renders Nereocystis unable to reproduce. [20] The tissues of bull kelp are processed and turned into liquid fertilizer as well as food for abalones.
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. [20]
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. [20]
Kelps are large brown algae or seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant but a stramenopile, a group containing many protists.
Brown algae are a large group of multicellular algae comprising the class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, Macrocystis, a kelp of the order Laminariales, may reach 60 m (200 ft) in length and forms prominent underwater kelp forests that contain a high level of biodiversity. Another example is Sargassum, which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Some members of the class, such as kelps, are used by humans as food.
Membranipora membranacea is a very widely distributed species of marine bryozoan known from the Atlantic and Pacific Oceans, usually in temperate zone environments. This bryozoan is a colonial organism characterized by a thin, mat-like encrustation, white to gray in color. It may be known colloquially as the coffin box, sea-mat or lacy crust bryozoan and is often abundantly found encrusting seaweeds, particularly kelps.
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 Earth. Although algal kelp forest combined with coral reefs only cover 0.1% of Earth's total surface, they account for 0.9% of global primary productivity. Kelp forests occur worldwide throughout temperate and polar coastal oceans. In 2007, kelp forests were also discovered in tropical waters near Ecuador.
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 photosynthesis.
Alaria esculenta is an edible seaweed, also known as dabberlocks or badderlocks, or winged kelp, and occasionally as Atlantic Wakame. It is a traditional food along the coasts of the far north Atlantic Ocean. It may be eaten fresh or cooked in Greenland, Iceland, Scotland and Ireland. It is the only one of twelve species of Alaria to occur in both Ireland and in Great Britain.
Laminaria is a genus of brown seaweed in the order Laminariales (kelp), comprising 31 species native to the north Atlantic and northern Pacific Oceans. This economically important genus is characterized by long, leathery laminae and relatively large size. Some species are called Devil's apron, due to their shape, or sea colander, due to the perforations present on the lamina. Others are referred to as tangle. Laminaria form a habitat for many fish and invertebrates.
Macrocystis is a monospecific genus of kelp 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 brown algae. Macrocystis has pneumatocysts at the base of its blades. Sporophytes are perennial and the individual may live for up to three years; stipes/fronds within a whole individual undergo senescence, where each frond may persist for approximately 100 days. The genus is found widely in subtropical, temperate, and sub-Antarctic oceans of the Southern Hemisphere and in the northeast Pacific. Macrocystis is often a major component of temperate kelp forests.
Postelsia palmaeformis, also known as the sea palm or palm seaweed, is a species of kelp and classified within brown algae. It is the only known species in the genus Postelsia. The sea palm is found along the western coast of North America, on rocky shores with constant waves. It is one of the few algae that can survive and remain erect out of the water; in fact, it spends most of its life cycle exposed to the air. It is an annual, and edible, though harvesting of the alga is discouraged due to the species' sensitivity to overharvesting.
Alaria is a genus of brown alga (Phaeophyceae) comprising approximately 17 species. Members of the genus are dried and eaten as a food in Western Europe, China, Korea, Japan, and South America. Distribution of the genus is a marker for climate change, as it relates to oceanic temperatures.
Haliotis rufescens is a species of very large edible sea snail in the family Haliotidae, the abalones, ormers (British) or pāua. It is distributed from British Columbia, Canada, to Baja California, Mexico. It is most common in the southern half of its range.
Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of Rhodophyta (red), Phaeophyta (brown) and Chlorophyta (green) macroalgae. Seaweed species such as kelps provide essential nursery habitat for fisheries and other marine species and thus protect food sources; other species, such as planktonic algae, play a vital role in capturing carbon and producing at least 50% of Earth's oxygen.
Ecklonia maxima, or sea bamboo, is a species of kelp native to the southern oceans. It is typically found along the southern Atlantic coast of Africa, from the very south of South Africa to northern Namibia. In these areas the species dominates the shallow, temperate water, reaching a depth of up to 8 metres (26 ft) in the offshore kelp forests.
Pterygophora californica is a large species of kelp, commonly known as stalked kelp. It is the only species in its genus Pterygophora. It grows in shallow water on the Pacific coast of North America where it forms part of a biodiverse community in a "kelp forest". It is sometimes also referred to as woody-stemmed kelp, walking kelp, or winged kelp.
Laminaria hyperborea is a species of large brown alga, a kelp in the family Laminariaceae, also known by the common names of tangle and cuvie. It is found in the sublittoral zone of the northern Atlantic Ocean. A variety, Laminaria hyperborea f. cucullata is known from more wave sheltered areas in Scandinavia.
Aquaculture of giant kelp, Macrocystis pyrifera, is the cultivation of kelp for uses such as food, dietary supplements or potash. Giant kelp contains iodine, potassium, other minerals vitamins and carbohydrates.
Lessonia trabeculata is a species of kelp, a brown alga in the genus Lessonia. It grows subtidally off the coasts of Peru and northern and central Chile, with the closely related Lessonia nigrescens tending to form a separate zone intertidally. Lessonia trabeculata kelp have gained a great economic importance for alginate production, and its harvest has greatly intensified along the Chilean coast during past two decades
Laminaria ochroleuca is a large kelp, an alga in the order Laminariales. They are commonly known as golden kelp, due to their blade colouration, distinguishing them from Laminaria hyperborea
Lessonia corrugata is a species of kelp, a brown algae in the genus Lessonia, commonly known as strapweed, common crapweed, or Tasmanian kombu. It is a subtidal species endemic to Tasmania and southern Victoria, Australia, and is the least studied of the only three Laminarian kelps in the region. The species was first described by Arthur Henry Shakespeare Lucas in 1931, and is most closely related to the New Zealand species Lessonia variegata.