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Cladophora is a genus of branching filamentous green algae in the classUlvophyceae. They may be referred to asreticulated algae,branching algae,[2] orblanket weed.[3] The genus has a worldwide distribution, mainly found in marine or brackish waters; a few species are found infreshwater.[4] It is harvested for use as a food and medicine.
Cladophora forms thalli consisting of branched, uniseriate (one cell thick) filaments which are usually sparsely to profusely branched (rarely without any branching). The thallus may be attached to a substrate viarhizoid cells produced by the basal cell, or by a simple disc-like holdfast; alternatively it may be unattached. Filaments are wider at the base and narrower near the tips. Cells produce a branch directly below the cross-wall, or may be pseudo-dichotomously branched. Cells are cylindrical, barrel-shaped or club-shaped.[4]
The cells withinCladophora are large and multinucleate (with multiplenuclei) and have many parietal roundchloroplasts each with a singlepyrenoid, which usually join into a net-like reticular formation.[4]Cladophora bright grass-green in color due tochlorophyll a, andchlorophyll b, in ratios similar to those of higher plant; it also containsβ-carotene andxanthophylls.[5] Thick-walled swollen cells, calledakinetes, develop under unfavorable conditions.[4] times of shortphotoperiods, low temperatures or nutrient unavailability. The cell walls ofCladophora species often containcellulose andpectin, providing strength and flexibility.[5]
The filaments can be quite long and may form dense mats or tufts in aquatic environments. WhenCladophora becomes detached from the rocky substrate that it grows upon, it can then build up on shorelines, making their reticular formations, (dense mats) visible to onlookers. When dense mats form, this can affect light penetration and oxygen levels in aquatic ecosystems. Mats may also serve as habitat and food for various aquatic organisms.[5]
Temperature, water currents and waves affect their metabolism and morphology, and branching patterns. At 15–20 °C branches appear alternate, they can also appear completely absent in temperatures below 25 °C.[5]
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This plant is annual and can reproduce through both sexual and asexual mechanisms. Some species have isogametic capacities but little is known about this and it seems to be a rare occurrence present in few species. The few cases that have occurred were in apical and sub apical un-specialized cells. Cladophora generally reproduces asexually using 2 flagellatedzoospores using mitotic division and distal cells of side branches.
This occurs when the male and female gametes fuse, usually in water. The fusion of gametes results in the formation of a diploid zygote. The diploid zygote undergoes mitotic divisions to form a diploid sporophyte. The sporophyte phase is often short-lived and less conspicuous. It produces haploid spores through meiosis. Haploid spores are released from the sporophyte and can be dispersed by water currents or other means. Haploid spores germinate to form new haploid gametophytes, completing the life cycle. Reproductive cells, often referred to as zoospores, are typically motile and possess flagella, allowing them to move in water.
UnlikeSpirogyra the filaments ofCladophora branch and do not undergo conjugation.
There are two multicellular stages in its life cycle – ahaploidgametophyte and adiploidsporophyte – which look highly similar. The only way to tell the two stages apart is to either count theirchromosomes, or examine their offspring. The haploid gametophyte produces haploid gametes bymitosis and the diploid sporophyte produces haploid spores bymeiosis. The only visible difference between the gametes and spores ofCladophora is that the gametes have twoflagella and the spores have four.
Cladophora exist in multiple ecosystems which include both tropical and moderate climates, freshwater, wastewater, and marine water ecosystems, and in multiple biomes which include lakes, ponds, dam reservoirs, large rivers and the coastallittoral zones as well as in areas of oceanic depth (which determines temperatures and light availability as well as oxygen availability, which can become a limiting factor). This taxon needsnitrates, and orthophosphates, as well as hard water conditions with pH levels between 7–10, high light intensity and nutrient densities that are rich in nature.Cladophora may attach to submerged surfaces like rocks or other aquatic substrates, enabling it to grow more rapidly through optimization of space availability, (another limiting factors and source of infraspecific, intraspecies and interspecies competition).[6]
In Europe, only 15 known subtypes ofCladophora are freshwater.Cladophora exists in Africa, Asia, the Pacific Islands, Australia, Europe, the Atlantic Islands, North America, New Zealand, as well as the Caribbean. In some Asian countries, almost 5% of human diets are algae, and its consumption is popular in France, Thailand, as well as the Hawaiian Islands.[5]
Cladophora balls are formed from the filaments of the algae[7] which are photosynthetic. Large numbers of these balls were thrown ashore in Devon, England. They had an average diameter of 2.5 cm and several million balls were found forming a layer.[8]
The genusCladophora iscosmopolitan and accordingly infestations cannot often be regarded logically as being invasive. Where they occur they may at various times be seen as beneficial, as a nuisance, or an outright pest.[citation needed]
Modest growth ofCladophora is generally harmless; the growth is an important food for many fish and other aquatic animals, as a buffer for the sequestration of nutrients in the water body and for protection of some aquatic organisms from solarultraviolet radiation.[citation needed]Cladophora species can be an environmental nuisance, however, causing major alterations tobenthic conditions linked particularly with increasedphosphorus loading.[5]
WhereCladophora becomes a pest is generally where special circumstances cause such drastic overgrowth thatalgal blooms develop and form floating mats. Typical examples include wherehypertrophication or high mortality of rival organisms produce high concentrations of dissolved phosphorus. Extensive floating mats prevent circulation that is necessary for the aeration of deeper water and, by blocking the light, they kill photosynthesising organisms growing beneath. The mats interfere with the fishing industry by clogging nets and preventing the use of lines. Where they wash ashore the masses of rotting material reduce shoreline property values along water bodies such as theGreat Lakes in the United States.[9]
Quagga mussel populations have increased tremendously during the same time frame as the blooming ofCladophora, though their ecological relationships are not yet clear and may be complex.[10]
SomeCladophora species, includingCladophora fascicularis, have been investigated for their use inphytoremediation.Cladophorafascicularis may contribute to improving water quality in contaminated aquatic ecosystems. This algae isbiologically active.Cladophora possesses unprecedented capacities to filter toxins from water such asheavy metals and pollutants and efficiently absorb nutrients, includingnitrogen andphosphorus.[5]
Cladophora is known for its blooming activities which are seasonal, (early spring to summer) and indicate theireutrophic abilities as well as that pollution may be present in the environment that they are growing within.[5]
Cladophora can be eaten as a food item either dried or fresh, however it loses some of its nutritional value with increased processing and with genetic modification. It is considered a carbohydrate when consumed.[5]
InLaos,Cladophora are commonly eaten as a delicacy and usually known in English under the name "Mekong weed". The algae grow on underwater rocks and thrive in clear spots of water in theMekong river basin. They are harvested 1 to 5 months a year and most often eaten in dry sheets similar to Japanesenori, though much cruder in their format.Luang Prabang's speciality is dry khai with sesame (kaipen), whileVang Vieng is famous for its roasted kháy sheets. They can be eaten in strips as anappetizer, with a meal or as a snack with Beer Lao. Luang Prabang kháy sheetskaipen are the most readily available form of Mekong weed and are famous throughout the country and in the neighbouringIsaan, though difficult to find beyondVientiane. Mekong weed can also be eaten raw, in soups, or cooked insteamed curries.[citation needed]
Trans-esterification ofCladophora can be used to transform it into biodiesel. Alcohols and enzymes andCladophora oils are used to form this reaction, but production is often highly dependent on oil content.[5]
Cladophora has pharmacological uses as medication.Cladophora is purported to have antimicrobial,antihistamine, antiviral, antioxidant, anti-sclerosis, anti-inflammatory and weight loss properties as well assecondary metabolites andbioactive components that have uses in diabetes, hypertension, cancer, and serves as a protection from parasites. However, as of December 2023,Cladophora has yet to be utilized commercially as a pharmacological agent.[5]
There is an additional demand forCladophora forbiomass productivity with utilization commercially as material for value added products. It can be used for cosmetic application and used as a fertilizer.[5]Marimo used to be classified inCladophora, though is now calledAegagropila linnaei. Algae balls are significant in the hobby aquarium trade.[citation needed]
As of 2025,AlgaeBase accepts 190 species within the genusCladophora.[1]
Cladophora has had a long and complicated taxonomic history. It was first described byFriedrich Traugott Kützing in 1843, who described many new species and varieties based on minor differences in morphology; subsequent authors did the same, resulting in hundreds of species names.[4] HoweverCladophora displays extensivephenoplastic plasticity in response to different environmental conditions;[11] the same plant may have a drastically different appearance in fresh or salt water. In the 20th century,Christian van den Hoek and other authorssynonymized many names, gradually reducing the number of accepted species. On the other hand, molecular data has shown thatCladophora containscryptic diversity. Therefore, it is difficult to know the true number ofCladophora species.[4]
The simple morphology ofCladophora has independently evolved multiple times in the order Cladophorales, making itpolyphyletic. Taxonomic studies includingmolecular phylogenetics have begun to splitCladophora into smallermonophyletic genera, but the resulting genera often overlap significantly in terms of morphology.[4]
Some species include:
Related genera with species formerly included inCladophora are:
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