Ulva australis | |
---|---|
Scientific classification | |
(unranked): | Viridiplantae |
Division: | Chlorophyta |
Class: | Ulvophyceae |
Order: | Ulvales |
Family: | Ulvaceae |
Genus: | Ulva |
Species: | U. australis |
Binomial name | |
Ulva australis Areschoug, 1854 | |
Ulva australis, the southern sea lettuce, is a species of bright green coloured seaweed in the family Ulvaceae that can be found in waters around Australia and was first described by Swedish botanist Johan Erhard Areschoug. It is an edible green algae, although sometimes designated as a seaweed. [1] General characteristics of Ulva australis include a smooth surface, distromatic blades, lobed fronds, and thallus color from dark green to light grass green. It can be either free floating or attached by a single holdfast. Its cells appear to be irregularly arranged, have rounded edges, and have shapes such as rectilinear, square, and pentagonal. [2]
It has been researched for a number of scientific properties in distinct fields such as environmental protection, medicine, and pharmacology. [3] [4] [5] [6] Ulva rigida has sometimes been confused with this species. [7]
The taxa of Ulva macro-algae are distributed worldwide, and because they have so few characters that are often different among the taxa members, they are known to be difficult to classify. Many Ulva members found near the Australia has been equated with species elsewhere in the world, and Ulva australis, first described from the samples Arechoug collected in Southern Australia, is one of them. [2]
Once considered to be a temperate species, Ulva pertusa is one of the most common green algae in Japan that lives in the intertidal coast, and it is native to northeastern Asia. Upon studying the DNA fragments extracted from collected specimens, Ulva pertusa has almost identical DNA sequences, with very small sequence divergence when comparing with the reported genetic data from Australia. The researchers tested the hypothesis that U. australis is an independent species, but, the hypothesis was rejected due to U. australis' natural habitat along the shoreline being suppressed by the U. pertusa populations. Therefore, it can be concluded that the Ulva australis is a species introduced to Australia that originated in Japan. However, the researchers hypothesize that the U. australis was not directly introduced from Japan to Australia, but rather from non-indigenous populations elsewhere in northeastern Asia. [8]
Researchers used a factorial experimental design to test the three factors that has influence on the growth of Ulva australis with two levels of each factor: Carbon dioxide (380 and 750 ppm), nutrient (control and PES medium), and irradiance (50 and 100 μmol photons m−2 s−1). It was experimentally shown that the growth and photosynthesis of Ulva australis increases when the levels of carbon dioxide and nutrient are higher, i.e. 750 ppm and PES medium in the experiment. However, the optimal level for irradiance for their growth and photosynthesis differed among the three lives stages. The germlings favored higher level of irradiance, whereas the preferred lower level of irradiance. [9]
Ulva australis has the ability to participate in environmental protection. Human activities has released metals into the sea, and when these metals exceed the standard, they will cause metal pollution. Measuring and removing these pollutants has always been a problem. When Ulva australis are in the sea area with serious metal pollution, the metal ions in their cell walls and vacuoles will increase, which indicates that they can absorb metals in the ocean. In addition, the research results also show that compared with other metals, they have stronger absorption capacity for zinc. The results indicate that the metal pollution of a given area could be known by transplanting Ulva australis into the polluted area and measuring the metal ion content in its cell wall and vacuole. Moreover, Ulva australis can also be used as biological tools to remove metal pollution. The metal absorption capacity of Ulva australis has an upper limit, and excessive metal pollution will damage their thallus, thus it is necessary to replace Ulva australis regularly during use. [10]
Ulva australis, as an edible seaweed, is very rich in minerals, vitamins, and noncaloric dietary fiber, [11] and has many uses in medical and biotechnological fields. The decoction of U. australis can be used to treat several illness such as hyperlipidemia, sunstroke, and urinary diseases. [12] Several biological activities such as anti-hyperlipidemic, [13] antioxidant, [14] antiviral, [15] immunomodulatory, [16] and anti-radiation activities [17] were all observed from the algal sulfated polysaccharides they have. [18] The organic extracts of Ulva australis also show different many other biological activities, such as radical scavenging activity (RSA) and metal chelating activity. Moreover, Ulva australis also shows inhibitory effects on the pathogenic factors of Alzheimer's disease, hyperpigmentation, Type-2 diabetes mellitus and skin sagging. This shows that Ulva australis as a common food source can be used to treat, prevent or alleviate a variety of diseases. [19]
Research shows that Ulva australis can play a great role in abalone aquaculture: improve the survival rate of abalone, and reduce the cost of abalone farming. Abalone is widely known as an expensive seafood with large demand. However, the utilization rate of Undaria pinnatifida as its feed is not high in winter and it will lead to unbalanced nutrition, which not only reduces the survival rate of abalone, but also increases the cost of aquaculture. Therefore, some researchers use Ulva australis instead of Undaria pinnatifida as abalone feed to experiment, to observe whether Ulva australis can be used as an effective abalone feed. The results showed that when 60% Ulva australis and 40% Undaria pinnatifida were used to feed abalone, the survival rate and abundance of abalone reached the maximum. Moreover, even if abalone is completely fed with Ulva australis instead of Undaria pinnatifida, abalone will not be negatively affected. [20] [21]
Green tide, a phenomenon of excessive green algae in a certain area, is mainly caused by Ulva spp. [22] In Jeju Island and its coastal areas of South Korea, Ulva australis, a specie of Ulva spp., has caused serious ecological and marine pollution. Therefore, it is imminent to resolve the issue. Some researchers have carried out experiments with different control measures and found that the reproductive capacity of Ulva australis in low salinity water is inhibited. Moreover, lower pH value and temperature higher than 30 °C will also cause serious damage to Ulva australis. In addition, the researchers also pointed out that oxidants such as hydrogen peroxide and sodium percarbonate can cause the rapid death of Ulva australis, thus these chemicals can be used to control the green tide caused by Ulva australis. [20]
Chlorophyta is a taxon of green algae informally called chlorophytes. The name is used in two very different senses, so care is needed to determine the use by a particular author. In older classification systems, it is a highly paraphyletic group of all the green algae within the green plants (Viridiplantae) and thus includes about 7,000 species of mostly aquatic photosynthetic eukaryotic organisms. In newer classifications, it is the sister clade of the streptophytes/charophytes. The clade Streptophyta consists of the Charophyta in which the Embryophyta emerged. In this latter sense the Chlorophyta includes only about 4,300 species. About 90% of all known species live in freshwater. Like the land plants, green algae contain chlorophyll a and chlorophyll b and store food as starch in their plastids.
Mariculture or marine farming is a specialized branch of aquaculture involving the cultivation of marine organisms for food and other animal products, in enclosed sections of the open ocean, fish farms built on littoral waters, or in artificial tanks, ponds or raceways which are filled with seawater. An example of the latter is the farming of marine fish, including finfish and shellfish like prawns, or oysters and seaweed in saltwater ponds. Non-food products produced by mariculture include: fish meal, nutrient agar, jewellery, and cosmetics.
The green algae are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as sister of the Zygnematophyceae. Since the realization that the Embryophytes emerged within the green algae, some authors are starting to include them. The completed clade that includes both green algae and embryophytes is monophyletic and is referred to as the clade Viridiplantae and as the kingdom Plantae. The green algae include unicellular and colonial flagellates, most with two flagella per cell, as well as various colonial, coccoid and filamentous forms, and macroscopic, multicellular seaweeds. There are about 22,000 species of green algae. Many species live most of their lives as single cells, while other species form coenobia (colonies), long filaments, or highly differentiated macroscopic seaweeds.
Wakame(Undaria pinnatifida) is a species of kelp native to cold, temperate coasts of the northwest Pacific Ocean. As an edible seaweed, it has a subtly sweet, but distinctive and strong flavour and texture. It is most often served in soups and salads.
The sea lettuces comprise the genus Ulva, a group of edible green algae that is widely distributed along the coasts of the world's oceans. The type species within the genus Ulva is Ulva lactuca, lactuca being Latin for "lettuce". The genus also includes the species previously classified under the genus Enteromorpha, the former members of which are known under the common name green nori.
Caulerpa is a genus of seaweeds in the family Caulerpaceae. They are unusual because they consist of only one cell with many nuclei, making them among the biggest single cells in the world.
Ulva lactuca, also known by the common name sea lettuce, is an edible green alga in the family Ulvaceae. It is the type species of the genus Ulva. A synonym is U. fenestrata, referring to its "windowed" or "holed" appearance.
Halimeda is a genus of green macroalgae. The algal body (thallus) is composed of calcified green segments. Calcium carbonate is deposited in its tissues, making it inedible to most herbivores. However one species, Halimeda tuna, was described as pleasant to eat with oil, vinegar, and salt.
Fucoidan is a long chain sulfated polysaccharide found in various species of brown algae. Commercially available fucoidan is commonly extracted from the seaweed species Fucus vesiculosus, Cladosiphon okamuranus, Laminaria japonica and Undaria pinnatifida. Variant forms of fucoidan have also been found in animal species, including the sea cucumber.
Codium is a genus of edible green macroalgae under the order Bryopsidales. The genus name is derived from a Greek word that pertains to the soft texture of its thallus. One of the foremost experts on Codium taxonomy was Paul Claude Silva at the University of California, Berkeley. P.C. Silva was able to describe 36 species for the genus and in honor of his work on Codium, the species C. silvae was named after the late professor.
Monostroma is a genus of marine green algae (seaweed) in the family Monostromataceae. As the name suggests, algae of this genus are monostromatic. Monostroma kuroshiense, an algae of this genus, is commercially cultivated in East Asia and South America for the edible product "hitoegusa-nori" or "hirohano-hitoegusa nori", popular sushi wraps. Monostroma oligosaccharides with degree of polymerization 6 prepared by agarase digestion from Monostroma nitidum polysaccharides have been shown to be an effective prophylactic agent during in vitro and in vivo tests against Japanese encephalitis viral infection. The sulfated oligosaccharides from Monostroma seem to be promising candidates for further development as antiviral agents. The genus Monostroma is the most widely cultivated genus among green seaweeds.
Rhipiliopsis is a genus of green algae in the family Rhipiliaceae. Johnson-sea-linkia is a synonym.
Udotea is a genus of green algae in the family Udoteaceae.
The genus Umbraulva, which is a green alga within the Ulvaceae family, was proposed by Bae and Lee in 2001. Three additional species, including U. kuaweuweu, which was subsequently transferred to another genus, have been added to the genus since it originally had the three species that were initially examined to form the genus. Umbraulva species grow upon hard substrates, and inhabit deep subtidal areas. Species within this genus are widely distributed, and have been identified in Asia, Europe, Hawaii, and New Zealand. The morphological traits of Umbraulva vary among species, but commonly, Umbraulva are macroscopic with olive green blades containing the photosynthetic pigment siphonaxanthin. The blades are flattened and ellipsoid in shape, or are narrow and oval shaped, with perforations and/or lobes present throughout the blade. As Umbraulva often appear very similar in morphology to closely related groups, the main manner in which Umbraulva was differentiated from related groups was through the divergence of ITS and partial SSU rDNA sequences from those of other Ulva species. Umbraulva is closely related to Ulva, which due to wide distributions, high carbohydrate levels, and a lack of lignin, is a good candidate for use in biofuel, bioremediation, carbon sequestration, and animal feed production.
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, producing at least 50% of Earth's oxygen.
Edible seaweed, or sea vegetables, are seaweeds that can be eaten and used for culinary purposes. They typically contain high amounts of fiber. They may belong to one of several groups of multicellular algae: the red algae, green algae, and brown algae. Seaweeds are also harvested or cultivated for the extraction of polysaccharides such as alginate, agar and carrageenan, gelatinous substances collectively known as hydrocolloids or phycocolloids. Hydrocolloids have attained commercial significance, especially in food production as food additives. The food industry exploits the gelling, water-retention, emulsifying and other physical properties of these hydrocolloids.
Seaweed farming or kelp farming is the practice of cultivating and harvesting seaweed. In its simplest form farmers gather from natural beds, while at the other extreme farmers fully control the crop's life cycle.
Ulva linza is a green alga in the family Ulvaceae that can be found in British Isles.
Ulva conglobata is a species of seaweed in the family Ulvaceae that can be found on Jeju Island of Korea, Qingdao province of China and Yokohama, Japan.
Monostroma kuroshiense, a green alga in the division Chlorophyta, is a green seaweed endemic to Kuroshio Coast of Japan. This high-value seaweed is called Hitoegusa or Hirohano hitoegusa (ヒロハノヒトエグサ) in Japanese. Previously this algae was known in binomen Monostroma latissimum, but the latest scientific research based on multilocal phylogeny discovered that this is a new species. The algae is named after Kuroshio Current, naming is done by phycologist Felix Bast This algae is commercially cultivated in East Asia and South America for the edible product "hitoegusa-nori" or "hirohano-hitoegusa nori", popular sushi wraps. Monostroma oligosaccharides with degree of polymerization 6 prepared by agarase digestion from Monostroma nitidum polysaccharides have been shown to be an effective prophylactic agent during in vitro and in vivo tests against Japanese encephalitis viral infection. The sulfated oligosaccharides from Monostroma seem to be promising candidates for further development as antiviral agents. The genus Monostroma is the most widely cultivated genus among green seaweeds.
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