''Durvillaea antarctica'', also known as ' and ', is a large, robust species of southern bull kelp found on the coasts of

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, southern

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island country ...

, and

Macquarie Island Macquarie Island is an island in the southwestern Pacific Ocean, about halfway between New Zealand and Antarctica. Regionally part of Oceania and politically a part of Tasmania, Australia, since 1900, it became a Tasmanian State Reserve in ...

.Smith, J.M.B. and Bayliss-Smith, T.P. (1998). Kelp-plucking: coastal erosion facilitated by bull-kelp ''Durvillaea antarctica'' at subantarctic Macquarie Island, ''Antarctic Science'' 10 (4), 431–438. . ''D. antarctica'', an

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mi ...

, does not have air bladders, but floats due to a unique honeycomb structure within the alga's blades, which also helps the

kelp Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant - it is a heterokont, a completely unrelated group of organisms. Kelp grows in "under ...

avoid being damaged by the strong waves.Maggy Wassilieff
Seaweed - Bull kelp’s honeycombed structure
''Te Ara - the Encyclopedia of New Zealand'', Ministry of Culture and Heritage. Updated 2 March 2009. Retrieved 9 March 2010.

Taxonomy

The species was first described in 1822, as ''Fucus antarcticus'', and revised in 1892 as ''Durvillaea antarctica''. The genus name ''Durvillaea'' was given in memory of the French explorer

Jules Dumont d'Urville Jules Sébastien César Dumont d'Urville (; 23 May 1790 – 8 May 1842) was a French explorer and naval officer who explored the south and western Pacific, Australia, New Zealand, and Antarctica. As a botanist and cartographer, he gave his n ...

, while the

Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

derived epithet refers to

antarctic The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and oth ...

. In 2012, a taxonomic revision led to the recognition of a new species, '' Durvillaea poha'', based on genetic, morphological and ecological evidence, which was previously recognised as the 'cape' lineage of ''Durvillaea antarctica''. ''D. poha'' is the only other species in the genus to share the honeycombed structure and buoyancy of ''D. antarctica.'' ''D. poha'' occurs only in southern New Zealand and on subantarctic islands (including Snares and

Auckland Islands The Auckland Islands (Māori: ''Motu Maha'' "Many islands" or ''Maungahuka'' "Snowy mountains") are an archipelago of New Zealand, lying south of the South Island. The main Auckland Island, occupying , is surrounded by smaller Adams Island, ...

), whereas ''D. antarctica'' has a wider distribution, and is found around New Zealand, Chile and other subantarctic islands. In southern New Zealand, ''D. poha'' and ''D. antarctica'' can be found growing together, although ''D. poha'' normally grows higher up or further back on the rock platforms, or in more sheltered bays, where wave force is weaker. ''D. poha'' generally has wider fronds than ''D. antarctica'', and can appear more 'orange' across the frond area. Mitochondrial

introgression Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Intr ...

has been observed between the two species, where some plants in Wellington exhibited the nuclear DNA of ''D. poha'' but also mitochondrial DNA belonging to ''D. antarctica''. Further diversity, with additional unclassified lineages have been identified within the species.

Description

The blades of ''Durvillaea antarctica'' are green to golden brown with a leathery texture. The honeycomb structure of the blade gives strength and buoyancy. This novel structure is thought to be responsible for the wide distribution of this genus, as the kelp is able to float when its holdfast fails. It can colonise other coastlines in this manner, and has been shown to carry communities of invertebrates across vast ocean distances from one shore to another. Specimens of ''D. antarctica'' have been found to float for up to 210 days, during which time high wind speeds transport kelp rafts up to 10,000 km. Environmental factors such as temperature, solar radiation and surface winds (all of which vary with latitude) affect buoyancy of rafts and their rate of travel. Rafts of ''D. antarctica'' are more likely to disperse offshore if plants detach during outgoing tides during autumn and winter. It is thought that this 'rafting' with ''Durvillaea antarctica'' and other floating seaweeds allowed a wide range of species to recolonise sub-Antarctic shores scoured clean by ice during the last Ice Age. The holdfast of ''D. antarctica'' is large and is very difficult to remove. ''D. antarctica'' has to resist forces equivalent to 1100 km/h on land. The holdfast failing is usually the result of worms and molluscs which feed on the tissue because of the sheltered habitat it creates. It is also common for its host rock to be broken off without the holdfast losing its grip, with this contributing significantly to erosion in some areas. Recruitment rates of this species is very low, therefore the ecological impact of harvesting this species is too great.

Life cycle

''Durvillaea antarctica'' reproduces sexually by producing egg and sperm that are released into the water. Eggs and sperm are produced on specific sites of the frond. A large individual can produce 100 million eggs in twelve hours. The season when reproduction occurs varies with location, but is generally during winter months.

Distribution

''Durvillaea antarctica'' has a circumpolar distribution between the latitudes of 29°S and 55°S, found in Chile, southern New Zealand, and Macquarie Island. The type locality is Cape Horn, Chile. It is found on exposed shores, especially in the northern parts of its range, and attaches itself with a strong holdfast.

Epifauna, parasites and rafting

Holdfasts of ''D. antarctica'' are often inhabited by a diverse array of epifaunal invertebrates, many of which burrow into and graze on the kelp. In New Zealand, epifaunal species include the crustaceans '' Parawaldeckia kidderi'', '' P. karaka'' and '' Limnoria stephenseni'', and the

molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is es ...

'' Cantharidus roseus'', '' Onchidella marginata'', '' Onithochiton neglectus'', and '' Sypharochiton sinclairi''. The intertidal spider '' Desis marina'' also inhabits the holdfasts of ''D. antarctica''.Vink, C., McQuillan, B., Simpson, A., & Correa-Garhwal, S. (2017). The marine spider, ''Desis marina'' (Araneae: Desidae): new observations and localities. ''The Weta, 51'', 71-79. Retrieved from http://publications.ento.org.nz/index.php/weta/article/view/167 Plants of ''D. antarctica'' can from detach substrates, particularly during storms. The kelp floats as a raft and can travel vast distances at sea, driven by ocean currents. Kelp-associated invertebrates can be transported inside of drifting holdfasts, potentially leading to long-distance dispersal and a significant impact upon the population genetic structure of those species. Fronds of ''D. antarctica'' can be infected by an endophytic, phaeophycean algal parasite '' Herpodiscus durvillaeae'' (Lindauer) G. R. South. Fronds can also be infected '' Maullinia'', a genus of intracellular, protistan parasites. Based on genetic evidence, both ''H. durvillaeae'' and ''Maullinia'' have likely been dispersed across the Southern Hemisphere via rafting bull kelp.

Human use

Chilean culture

Use in cuisine

Stems and holdfasts of ''D. antarctica'' and '' D. incurvata'' are harvested from the coast of Chile and is used in

Chilean cuisine Chilean cuisine stems mainly from the combination of traditional Spanish cuisine, Chilean Mapuche culture and local ingredients, with later important influences from other European cuisines, particularly from Germany, the United Kingdom an ...

for various recipes, including

salad A salad is a dish consisting of mixed, mostly natural ingredients with at least one raw ingredient. They are typically served at room temperature or chilled, though some can be served warm. Condiments and salad dressings, which exist in a va ...

s and

stew A stew is a combination of solid food ingredients that have been cooked in liquid and served in the resultant gravy. A stew needs to have raw ingredients added to the gravy. Ingredients in a stew can include any combination of vegetables and ...

s. In Quechua the species is called: ' (': lake, and ': weed), and ''hulte''. The

Mapuche The Mapuche ( (Mapuche & Spanish: )) are a group of Indigenous peoples of the Americas, indigenous inhabitants of south-central Chile and southwestern Argentina, including parts of Patagonia. The collective term refers to a wide-ranging ethnicit ...

indigenous people refer to it as or .

Expression

The expression ''remojar el cochayuyo'' (literally: to soak the cochayuyo) is used in

Chilean Spanish Chilean Spanish ( es, español chileno) is any of several varieties of the Spanish language spoken in most of Chile. Chilean Spanish dialects have distinctive pronunciation, grammar, vocabulary, and slang usages that differ from those of Stand ...

to refer to

sexual intercourse Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal pene ...

.La Ficha Pop
,

La Cuarta ''La Cuarta'' ( es, The Fourth One) is a Chilean daily tabloid and part of the Copesa group. The newspaper is famous for its tone and plebeian style of headlining stories. The newspaper began publication on 13 November 1984. On 17 November 20 ...

, 31 October 2006. The expression derives from the fact that harvested ''D. antarctica'' is preserved by being sun-dried and then softened by soaking in a dish of water.

Māori culture

Along with '' D. poha'', blades of ''D. antarctica'' are used to make traditional pōhā bags, which are used to carry and store food and fresh water, to propagate live

shellfish Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater e ...

, and to make clothing and equipment for sports. Pōhā are especially associated with

Ngāi Tahu Ngāi Tahu, or Kāi Tahu, is the principal Māori (tribe) of the South Island. Its (tribal area) is the largest in New Zealand, and extends from the White Bluffs / Te Parinui o Whiti (southeast of Blenheim), Mount Mahanga and Kahurangi Poin ...

and are often used to carry and store muttonbird (tītī) chicks. The species is called ' in

Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the ...

References

External links

Algaebase: 'Durvillaea antarctica'' (Chamisso) Hariot

Museum of New Zealand Te Papa Tongarewa: ''Durvillaea antarctica'' (Cham.) Har. (Species)

Critter of the Week NZ Bull Kelp
( Critter of the Week) {{Taxonbar, from=Q1765472 Fucales Biota of Chile Flora of Gough Island Flora of New Zealand Flora of Macquarie Island Flora of Heard Island and McDonald Islands Flora of the Kerguelen Islands Flora of the Prince Edward Islands Edible seaweeds Species described in 1822