''Macrocystis'' is a monospecific genus
of
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 ...
(large
brown algae
Brown algae (: alga) are a large group of multicellular algae comprising the class (biology), class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate ...
) 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
Brown algae (: alga) are a large group of multicellular algae comprising the class (biology), class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate ...
. ''Macrocystis'' has
pneumatocysts at the base of its
blade
A blade is the Sharpness (cutting), sharp, cutting portion of a tool, weapon, or machine, specifically designed to puncture, chop, slice, or scrape surfaces or materials. Blades are typically made from materials that are harder than those they a ...
s.
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 ...
s are perennial and the individual may live for up to three years; stipes/fronds within a whole individual undergo
senescence
Senescence () or biological aging is the gradual deterioration of Function (biology), functional characteristics in living organisms. Whole organism senescence involves an increase in mortality rate, death rates or a decrease in fecundity with ...
, where each frond may persist for approximately 100 days. The genus is found widely in
subtropical
The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...
, temperate, and sub-Antarctic oceans of the Southern Hemisphere and in the northeast Pacific. ''Macrocystis'' is often a major component of temperate
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 ...
s.
Despite its appearance, it is not a
plant
Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...
; it is a
heterokont
The stramenopiles, also called heterokonts, are protists distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached to flagella, in some they are attached to other areas of the cellular surface, an ...
. Giant kelp is common along the coast of the northeastern
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...
, from
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 ...
north to southeast
Alaska
Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
, and is also found in the southern oceans near
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
,
South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
,
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
, and
New Zealand
New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
. Individual algae may grow to more than long at a rate of as much as per day. Giant kelp grows in dense stands known as
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 ...
s, which are home to many marine animals that depend on the algae for food or shelter. The primary commercial product obtained from giant kelp is
alginate
Alginic acid, also called algin, is a naturally occurring, edible polysaccharide found in brown algae. It is hydrophilic and forms a viscous gum when hydrated. When the alginic acid binds with sodium and calcium ions, the resulting salts are k ...
, but humans also harvest this species on a limited basis for use directly as food. It is rich in
iodine
Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...
,
potassium
Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...
, and other minerals. It can be used in cooking in many of the ways other sea vegetables are used, and particularly serves to add flavor to bean dishes.
Description
''Macrocystis'' is a monospecific genus; the sole species is ''M. pyrifera''. Some individuals are so huge that the thallus may grow to up to 60 m (200 ft).
[C. van den Hoek, D.G. Mann and H.M. Jahns (1995) ]
Algae An Introduction to Phycology
'. Cambridge University Press, Cambridge. The stipes arise from a
holdfast and branch three or four times from near the base. Blades develop at irregular intervals along the stipe.
[Mondragon, Jennifer and Mondragon, Jeff (2003) ''Seaweeds of the Pacific Coast.'' Sea Challengers, Monterey, California. ][I.A. Abbott and G.J. Hollenberg (1976) ''Marine Algae of California.'' Stanford University Press, California. ] ''M. pyrifera'' grows to over 45 m (150 ft) long.
The stipes are unbranched and each blade has a gas bladder at its base.
[ Kain, J M (1991) ''Cultivation of attached seaweeds'' in Guiry, M D and Blunden, G (1991) ''Seaweed Resources in Europe: Uses and Potential.'' John Wiley and Sons.]
''Macrocystis pyrifera'' is the largest of all
algae
Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...
. The stage of the life cycle that is usually seen is the
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 ...
, which is perennial and individuals persist for many years. Individuals may grow to up to long or more. The kelp often grows even longer than the distance from the bottom to the surface as it will grow in a diagonal direction due to the ocean current pushing against the kelp.
[Hoek, C van den; D G Mann & H M Jahns. (1995) ]
Algae: An Introduction to Phycology
'. Cambridge: Cambridge University Press. The stalks arise from a basal meristem, with as many as 60 stalks in older well protected individuals.
Blades develop at irregular intervals along the stipe, with a single
pneumatocyst (gas bladder) at the base of each blade.
At the base of each stalk is a cluster of blades that lack pneumatocysts; instead they develop small sacks on the blade that release the biflagellated
zoospore
A zoospore is a motile asexual spore that uses a flagellum for locomotion in aqueous or moist environments. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Certain zoospores are ...
s: these are the sporophylls.
The smaller morphs, formerly identified as ''Macrocystis integrifolia'', have deep brown color on flattened rhizomes which are profusely dichotomously branched. Each is attached by branched root-like structures coming out of the sides of the rhizomes. Slender main stipes (about wide to long) come from the rhizome which is up to at the widest. Periodically wide and long flattened leaf-like branches derive from the stipe. They have furrowed surfaces and taper gradually, but then have an oval or rounded float where attached to the stipe. The blade-like branches have notched denticulate edges leading to the terminal blade at the tip of the stipe, which is separated by several smaller branches.
[ Phylum: Phaeophyta, Class: Phaeophyceae, Order: Laminariales, Family: Lessoniaceae, Macrocystis integrifolia (Bory)](_blank)
Pearson College UWC. Retrieved 6 February 2013 It grows to only long. It is found on intertidal rocks or shallow subtidal rocks along the
Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...
coast of
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
(
British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
to
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
) and South America.
AlgaeBase
AlgaeBase is a global species database of information on all groups of algae, both seaweed, marine and freshwater algae, freshwater, as well as sea-grass.
History
AlgaeBase began in March 1996, founded by Michael D. Guiry, Michael Guiry. Text ...
Species: Macrocystis integrifolia
/ref> In New Zealand ''M. pyrifera'' is found in the subtidal zone of southern North Island, the South Island, Chatham, Stewart, Bounty, Antipodes, Auckland and Campbell Islands. The species can be found on rock and on sheltered open coasts.
File:Giant Kelp - Macrocystis pyrifera (29296895168).jpg
File:Macrocystis pyrifera.jpg
File:Kelp forest Channel Islands.JPG, ''M. pyrifera'' growing in the Channel Islands
File:Bryozoans on Macrocystis01.jpg, ''Macrocystis integrifolia''
File:Sanc0063 - Flickr - NOAA Photo Library.jpg, Giant kelp
File:Alger, Macrocystis pyrifera, Nordisk familjebok.png,
File:Giantkelp2 300.jpg,
File:CAS Macrocystis 2.JPG,
File:CAS Macrocystis 4.JPG,
File:Kelpharvest 300.jpg,
File:Seaweed, Santa Cruz Harbor.JPG,
File:Paralabrax clathratus - Tokyosealifepark - 2019 1 8.webm,
Life cycle
The 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 ...
has many specialized blades growing near the holdfast. These blades bear various sori containing sporangia
A sporangium (from Late Latin, ; : sporangia) is an enclosure in which spores are formed. It can be composed of a unicellular organism, single cell or can be multicellular organism, multicellular. Virtually all plants, fungus, fungi, and many ot ...
, which release haploid
Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Here ''sets of chromosomes'' refers to the num ...
spores
In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plant ...
, which will grow into microscopic female and male gametophyte
A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the se ...
s. These gametophytes, after reaching the appropriate substrata, grow mitotically to eventually produce gametes.
Females release their eggs (oogonia
An oogonium (: oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes.
In the mammalian fetus
Oogonia are formed in lar ...
) along with a pheromone
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
, the lamoxirene. This compound triggers sperm release by males. The ''Macrocystis'' sperm consists of biflagellate non- synthetic antherozoids, which find their way to the oogonia following the lamoxirene. The egg is then fertilized to form the zygote
A zygote (; , ) is a eukaryote, eukaryotic cell (biology), cell formed by a fertilization event between two gametes.
The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individ ...
, which, through mitosis, begins growth.
''Macrocystis integrifolia'' is found on intertidal rocks or shallow subtidal rocks along the Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...
coast of North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
from British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
to California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
.[Abbott, I. A. & G. J. Hollenberg. (1976) ''Marine Algae of California.'' California: Stanford University Press. ][Macrocystis integrifolia Bory](_blank)
DeCew's Guide to the Seaweeds of British Columbia, Washington, Oregon, and Northern California, Center for Phycological Documentation, University Herbarium, University of California, Berkeley, 2002. 13 July 2007 It prefers water about to deep and exposed to the open sea and normal salinities, yet sheltered from full wave action.
Pearson College UWC. Retrieved 6 February 2013
''Macrocystis integrifolia'' alternates heteromorphic phases from a macroscopic sporophyte to dioecious microscopic gametophytes. It has been studied as a plant fertilizer, increasing bean yields up to 24% and chemical studies indicate presence of phytohormone-like substances.[Temple, W. D., A. A. Bomke]
Effects of kelp (Macrocystis integrifolia and Ecklonia maxima) foliar applications on bean crop growth
Plant and Soil, June 1989, Volume 117, Issue 1, pp. 85-92 (paywall)
Growth
''Macrocystis pyrifera'' is one of the fastest-growing organisms on Earth.[White, L P & L G Plaskett, (1982) ''Biomass as Fuel.'' Academic Press. ] They can grow at a rate of a day to reach over long in one growing season.[Davis, Chuck. (1991) ''California Reefs.'' San Francisco, California: Chronicle Books. ]
Juvenile giant kelp grow directly upon their parent female gametophyte
A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the se ...
. To establish itself, a young kelp produces one or two primary blades, and begins a rudimentary holdfast, which serves to anchor the plant to the rocky bottom. As the kelp grows, additional blades develop from the growing tip, while the holdfast enlarges and may entirely cover the rock to which it is attached.
Growth occurs with lengthening of the stipe (central stalk), and splitting of the blades. At the growing tip is a single blade, at the base of which develop small gas bladders along one side. As the bladders and stipe grow, small tears develop in the attached blade. Once the tears have completed, each bladder supports a single separate blade along the stipe, with the bladders and their blades attached at irregular intervals.[Prescott, G W. (1968) ''The Algae: A Review.'' Boston: Houghton Mifflin Company.]
Ecology
''Macrocystis'' typically grow forming extensive beds, large "floating canopies", on rocky substrata between the low intertidal. It was harvested by barges which used large blades to harvest up to 300 tons a day along the coast of California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
.
''Macrocystis pyrifera'' is found in North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
(Alaska
Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
to California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
), South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
, South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
, New Zealand
New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
, and southern Australia.AlgaeBase
AlgaeBase is a global species database of information on all groups of algae, both seaweed, marine and freshwater algae, freshwater, as well as sea-grass.
History
AlgaeBase began in March 1996, founded by Michael D. Guiry, Michael Guiry. Text ...
Species: Macrocystis pyrifera
/ref> It thrives in cooler waters where the ocean water temperature remains mostly below . The species is also found near Tristan da Cunha
Tristan da Cunha (), colloquially Tristan, is a remote group of volcano, volcanic islands in the South Atlantic Ocean. It is one of three constituent parts of the British Overseas Territories, British Overseas Territory of Saint Helena, Ascensi ...
in the Mid-South Atlantic Ocean.
Where the bottom is rocky and affords places for it to anchor, giant kelp forms extensive kelp beds with large "floating canopies". When present in large numbers, giant kelp forms 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 ...
s that are home to many marine species that depend upon the kelp directly for food and shelter, or indirectly as a hunting ground for prey. Both the large size of the kelp and the large number of individuals significantly alter the availability of light, the flow of ocean currents, and the chemistry of the ocean water in the area where they grow.[Lobban, C S & P J Harrison. (1994) ''Seaweed Ecology and Physiology.'' Cambridge: Cambridge University Press. ]
In high-density populations, giant kelp individuals compete with other individuals of the species for space and resources. Giant kelp may also compete with '' Pterygophora californica'' in these circumstances.
Where surface waters are poor in nutrients, nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
in the form of amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...
s is translocated up the stipe through sieve elements that very much resemble the phloem
Phloem (, ) is the living tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is ...
of vascular plant
Vascular plants (), also called tracheophytes (, ) or collectively tracheophyta (; ), are plants that have lignin, lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified Ti ...
s. Translocation of nutrients along the stipe may be as rapid as per hour. Most translocation occurs to move carbon
Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...
-rich photosynthate, and typically transfers material from mature regions to actively growing regions where the machinery of 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 ...
is not yet fully in place. Translocation also moves nutrients downward from light-exposed surface fronds to sporophylls (reproductive fronds) at the base of the kelp, where there is little light and thus little photosynthesis to produce food.
Recent research has shown that Arctic kelp forests can steadily increase pH levels by 0.15 units over a 10-day period during extended daylight conditions in summer. This pH regulation, driven by sustained photosynthetic activity, helps mitigate the harmful effects of ocean acidification and supports calcifying organisms such as bivalves and sea urchins.
Species
Initially, 17 species were described within the genus ''Macrocystis''. In 1874, Hooker, following blade morphology, put them all under the same taxon, ''Macrocystis pyrifera''. In modern times, the large number of species were re-classified based on the holdfast morphology, which distinguished three species ('' M. angustifolia'', '' M. integrifolia'', and '' M. pyrifera'') and on blade morphology, which added a fourth species ('' M. laevis'') in 1986. In 2009 and 2010, however, two studies that used both morphological and molecular assessments demonstrate that ''Macrocystis'' is monospecific (as ''M. pyrifera''), which is currently accepted by the phycological community (see AlgaeBase).
Morphs
Although ''Macrocystis'' is a monospecific genus, some split it into the four morphs, or sub-species, described below, following pre-2010 taxonomy:
* ''Macrocystis pyrifera
''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 br ...
'', known as giant kelp, most widely distributed ''Macrocystis'' species, found in intermediate-to-deep water of North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
(Alaska
Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
to California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
), South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
, South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
, New Zealand
New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
, and southern Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
.
* ''Macrocystis integrifolia'', typically found on intertidal rocks or shallow subtidal rocks of British Columbia, Mexico, Peru and Northern Chile. It was considered a distinct species based on blade and holdfast morphology.
* ''Macrocystis laevis'', a smaller, intertidal species, is found on the Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...
coast of North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
(British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
to California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
) and South America.
* ''Macrocystis angustifolia'' Bory, known as southern giant kelp, is found in shallow waters of South Africa and South Australia.[J.M. Huisman (2000) ''Marine Plants of Australia.'' University of Western Australia Press. ]
Distribution
''Macrocystis'' is distributed along the eastern Pacific coast from Alaska to Mexico and from Peru and along the Argentinian coast as well as in Australia, New Zealand, South Africa and most sub-Antarctic islands to 60°S.
Aquaculture
''Macrocystis pyrifera'' has been utilized for many years as a food source; it also contains many compounds such as iodine
Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...
, potassium
Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...
, other minerals vitamins and carbohydrates
A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ma ...
and thus has also been used as a dietary supplement.[Bushing, William W (2000]
''Giant Bladder Kelp ''
[Connor, Judith & Charles Baxter. (1989) ''Kelp Forests.'' Monterey, California: Monterey Bay Aquarium. ] In the beginning of the 20th century California kelp beds were harvested as a source for soda ash. With commercial interest increasing significantly during the 1970s and the 1980s this was primarily due to the production of alginate
Alginic acid, also called algin, is a naturally occurring, edible polysaccharide found in brown algae. It is hydrophilic and forms a viscous gum when hydrated. When the alginic acid binds with sodium and calcium ions, the resulting salts are k ...
s, and also for biomass production for animal feed due to the energy crisis during that period.[Neushul M (1987) Energy from marine biomass: The historicalrecord. In: Bird KT, Benson PH (eds), Seaweed Cultivation for Renewable Resources, ''Elsevier Science Publishers'', Amsterdam, 1–37.] However the commercial production of ''M. pyrifera'' never became reality. With the end of the energy crisis and the decline in prices of alginates, the research into farming ''Macrocystis'' also declined.
The demand for ''M. pyrifera'' is increasing due to the newfound uses of these plants such as fertilizer
A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Man ...
s, cultivation for bioremediation
Bioremediation broadly refers to any process wherein a biological system (typically bacteria, microalgae, fungi in mycoremediation, and plants in phytoremediation), living or dead, is employed for removing environmental pollutants from air, wate ...
purposes, 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 sea urchin
Sea urchins or urchins () are echinoderms in the class (biology), class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body cove ...
feed. There is current research going into utilizing ''M. pyrifera'' as feed for other aquaculture species such as shrimps. Recently, ''M. pyrifera'' has been examined as a possible feedstock for conversion into ethanol for biofuel
Biofuel is a fuel that is produced over a short time span from Biomass (energy), biomass, rather than by the very slow natural processes involved in the formation of fossil fuels such as oil. Biofuel can be produced from plants or from agricu ...
use.
Conservation
In recent years, the kelp forests have decreased dramatically throughout Japan, Chile, Korea, Australia and North America. Harvesting of kelp as a food source and other uses may be the least concerning aspect to its depletion. In the Northwest Pacific kelp forests in waters near large population centres may be most affected by the sewer/stormwater discharge.
The natural phenomenon known as El Niño
EL, El or el may refer to:
Arts and entertainment Fictional entities
* El, a character from the manga series ''Shugo Chara!'' by Peach-Pit
* Eleven (''Stranger Things'') (El), a fictional character in the TV series ''Stranger Things''
* El, fami ...
cycles warm, tropical water from the South Pacific to Northern waters. This has been known to kill off ''M. pyrifera,'' due to its need for cold waters it would usually find in the North Pacific Ocean. In California, El Niño also brought along a population bloom of purple sea urchins which feed on the giant kelp.
Tasmania
Off the coast of Tasmania
Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...
, kelp forests have been significantly affected by several factors, including warming waters, shifting of the East Australian current
The East Australian Current (EAC) is a warm, southward, western boundary current that is formed from the South Equatorial Current (SEC) crossing the Coral Sea and reaching the eastern coast of Australia. At around 15° S near the Australian co ...
(EAC), and invasion of long-spine sea urchins. Locals have noticed significant effects on the population 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 ...
, a food source for the Aboriginal Tasmanians
The Aboriginal Tasmanians (palawa kani: ''Palawa'' or ''Pakana'') are the Aboriginal people of the Australian island of Tasmania, located south of the mainland. At the time of European contact, Aboriginal Tasmanians were divided into a numb ...
for thousands of years. These changes have also affected the oyster
Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but no ...
farming industry. By saving oysters that have survived disease outbreaks, they have been able to continue their way of life. It was estimated that by 2019, 95 per cent of the giant kelp forests along Tasmania's east coast had been lost within just a few decades.[ Some of this loss was attributed by locals to the harvesting of the forests by Alginates Australia, which opened its factory near Triabunna in 1963, shutting down operations 10 years later as uneconomical. However, expert in ]marine ecosystem
Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in Saline water, waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 7 ...
s Craig Johnson says that the loss of the forests "is almost certainly the result of climate change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
". Water temperatures along the east coast of Tasmania have been rising at nearly four times the average rate globally. The EAC brings warmer waters, which are also nutrient-poor compared to the previously usual cold water around the coast. Common kelp ('' Ecklonia radiata'') is better at nitrogen storage than giant kelp, so has been taking over the areas formerly occupied by giant kelp.
''Macrocystis pyrifera'' has become Australia’s first federally-listed endangered marine community. Scientists and conservationists are continuously looking into ways to restore the once heavily populated species to its original state. Methods include artificial reef
An artificial reef (AR) is a human-created freshwater or marine benthic structure.
Typically built in areas with a generally featureless bottom to promote Marine biology#Reefs, marine life, it may be intended to control #Erosion prevention, erosio ...
s, reducing numbers of purple sea urchins in overpopulated areas, and planting roots along the ocean floor. Scientists had built 28 artificial reefs off Maria Island by 2019, and were hopeful of bringing the kelp forests back.
See also
* Largest organisms
References
Further reading
*Agardh, C A. (1820) ''Species algarum rite cognitae, cum synonymis, differentiis specificis et descriptionibus succinctis.'' Vol. 1, Part 1, pp. -iv 168. Lund: Berling.
*Buschmann, A., Varela, D., Hernández-González, M., & Huovinen, P. (2008). Opportunities and challenges for the development of an integrated seaweed-based aquaculture activity in Chile: determining the physiological capabilities of ''Macrocystis'' and ''Gracilaria'' as biofilters. ''Journal of Applied Phycology, 20''(5), 571-577.
*Buschmann, A. H., Hernández-González, M. C., Astudillo, C., Fuente, L. d. l., Gutierrez, A., & Aroca, G. (2005). Seaweed cultivation, product development and integrated aquaculture studies in Chile. ''World Aquaculture, 36''(3), 51-53.
*Chaoyuan, W., & Guangheng, L. (1987). Progress in the genetics and breeding of economic seaweeds in China. ''Hydrobiologia, 151-152''(1), 57-61.
* Connor, Judith & Charles Baxter. (1989) ''Kelp Forests.'' Monterey, California: Monterey Bay Aquarium.
* tp://ftp.fao.org/docrep/fao/012/i1013t/i1013t.pdf ''Fishery and Aquaculture Statistics'' (2007). retrieved from ftp.fao.org*Graham, M.H., Vásquez, J.A. and Buschmann, A.H. (2007) Global ecology of the giant kelp ''Macrocystis'': From ecotypes to ecosystems. ''Oceanography and Marine Biology: An Annual Review'' 45: 39-88.
*Huisman, J M (2000) ''Marine Plants of Australia.'' University of Western Australia Press.
* Lopez, James. "''Macrocystis pyrifera''." Monterey Bay Aquarium Research Institute. 2001. Monterey Bay Aquarium Research Institute. 10 Jan 2007
*Macchiavello, J., Araya, E., & Bulboa, C. Production of ''Macrocystis pyrifera'' (Laminariales;Phaeophyceae) in northern Chile on spore-based culture. ''Journal of Applied Phycology'', 1-7.
*Mariculture of Seaweeds. (2010). Retrieved from https://web.archive.org/web/20101226110745/http://aquanic.org/species/documents/6_Algae_3__Culturing.pdf
*North, W J, G A Jackson, & S L Manley. (1986) "''Macrocystis'' and its environment, knowns and unknowns." ''Aquatic Biology'' 26:9-26.
*Schiel, D. R., & Foster, M. S. (2015). ''The Biology and Ecology of Giant Kelp Forests''. University of California Press.
*Simenstad, C.A., Estes, J.A. and Kenyon, K.W., 1978. Aleuts, sea otters, and alternatestable state communities. ''Science, 200'': 403-411.
*Westermeier, R., Patiño, D., Piel, M. I., Maier, I., & Mueller, D. G. (2006). A new approach to kelp mariculture in Chile: production of free-floating sporophyte seedlings from gametophyte cultures of ''Lessonia trabeculata'' and ''Macrocystis pyrifera''. ''Aquaculture Research, 37''(2), 164-171.
*Westermeier, R., Patiño, D., & Müller, D. G. (2007). Sexual compatibility and hybrid formation between the giant kelp species Macrocystis pyrifera and M. integrifoliat (Laminariales, Phaeophyceae) in Chile. Journal of Applied Phycology, 19(3), 215-221.
External links
''Macrocystis pyrifa''
* Bushing, William W (2000
Retrieved 21 September 2008.
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