Codium | |
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Codium spongiosum off the Réunion coast | |
Scientific classification | |
Clade: | Viridiplantae |
Division: | Chlorophyta |
Class: | Ulvophyceae |
Order: | Bryopsidales |
Family: | Codiaceae |
Genus: | Codium Stackhouse, 1797 |
Type species | |
Codium tomentosum Stackhouse, 1797 | |
Species | |
See text |
Codium is a genus of edible green macroalgae (or seaweed) 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. [1] [2] Silva was able to describe 36 species for the genus, and in honor of his work on Codium, [1] the species C. silvae was named after the late professor. [3]
This genus is the largest member of the algal family Codiaceae and consequently under order Bryopsidales and it currently has about 143 confirmed species and four (4) unresolved members. [4] Stackhouse, unfortunately, failed to provide holotype specimens for C. tomentosum (type species) and some of its dichotomously branching congeners leading to misidentifications; P.C. Silva delineated C. tomentosum, C. fragile, and C. vermilara and established neotypes for each species to finally resolve this taxonomic blunder. [5]
Being a member of the order Bryopsidales, Codium is coenocytic and siphonous. [4] Their spongy thallus is composed of a single, multinucleated, branched, tubular cell called siphon which terminates at a swollen end called the utricle. [2] [3] [4] These siphons intertwine with each other to form the clear mesh-like center of the Codium thallus called the medulla while the utricles surround this central layer to form a green to dark-green palisade layer called the cortex. [5] [4]
The genus has a wide variety of thalli forms: (1) mat-forming, the thalli encrusts and adheres to given a substrate using its medullary filaments; (2) spherical, the thalli forms a ball and is superficially attached to an area using rhizoidal filaments; and (4) erect thalli, typically dichotomously branched with its medulla surrounded by utricles. [6] In addition to its thalli variations, the utricles which forms its thallus also has variety of forms, mainly based on their apical wall thickness and apex shapes. [6]
Similar to most seaweed species, Codium species also exhibit a wide range of morphological plasticity which has been a great challenge to its morphology-based taxonomy. [6] [7] [8]
In terms of its natural range, Codium has a latitudinal range that encompasses the tropical to temperate areas, however, this genus is not found in the frigid polar regions of the world. [9] [6]
Two of these species are very rare in Ireland. Codium adhaerens has been recorded from a few sites on the west coast and from Tory Island on the north coast in County Donegal. In 1837 it was found in Church Bay in County Antrim, [10] but has not been found there since.
There are other species of "doubtful validity":- Codium amphibium is included in William Henry Harvey's Phycologia Britannica Pl.xxxv. and noted as: "spreading in patches of great extent along the edge of the sea, over the surface of a turf-bog which meets the shore at Roundstone Bay" (Ireland).
Even though Codium species are well-distributed across the globe, certain species have managed to escape their natural range and invade other areas. In the case of C. fragile spp. tomentosoides, commonly known as "oyster thief", the increasing marine traffic has made it possible for it to escape its natural locality (Japan) and spread to Europe and USA forcing devastating biodiversity and aquacultural losses. [12]
Codium has been observed to inhabit both from the intertidal zone down to the subtidal area. [4]
Codium, like most ulvophycean seaweeds, exhibit a diplontic life history wherein the dominant diploid (2N) thallus produces the male and female gametangia that will produce the haploid (N) gametes through meiosis. [13] Moreover, Codium are also capable of fragmentation, which has led to its unwanted spread across the globe.
South Korea is the leading consumer and producer of farmed Codium (commonly known as cheonggak) in the world; with about 4000 metric tons of fresh weight produced in 2017 and valued at 2 million US dollars. [14] Farming and cultivation of Codium in South Korea is a thriving industry; their method first involves seeding a rope line with isolated pieces of utricles and medullary filaments [15] and finally transferring it into the open sea for the grow-out cultivation. [16]
A recent review on the bioactivity of the genus Codium has revealed that most of its polysaccharides, glycoproteins, galactans, anionic macromolecules, and other extracts/compounds have shown to have a variety of uses as immunostimulatory, anticoagulant, anticancer, anti-inflammatory, antibacterial, antifungal, and antiviral agent. [17]
Codium is used either fresh or dry and is typically cooked and seasoned with soy sauce and vinegar or mixed with kimchi. [14]
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.
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.
Gracilaria, also known as irish moss or ogonori, is a genus of red algae in the family Gracilariaceae. It is notable for its economic importance as an agarophyte meaning that it is used to make agar, as well as its use as a food for humans and various species of shellfish. Various species in the genus are cultivated among Asia, South America, Africa and Oceania. They produce over 90% of the world's agar.
Chordariaceae is a family of brown algae. Members of this family are may be filamentous, crustose with fused cells at the base, or they may be terete and differentiated into a central medulla and an outer photosynthetic cortex. They have a sporphytic thallus usually aggregated to form a pseudo-parenchyma.
Dictyotales is a large order in the brown algae containing the single family Dictyotaceae. Members of this order generally prefer warmer waters than other brown algae, and are prevalent in tropical and subtropical waters thanks to their many chemical defenses to ward off grazers. They display an isomorphic haplodiploid life cycle and are characterized by vegetative growth through a single apical cell. One genus in this order, Padina, is the only calcareous member of the brown algae.
Struvea is a genus of green macroalgae in the family Boodleaceae.
Udotea is a genus of green algae in the family Udoteaceae.
Turbinaria is a genus of brown algae (Phaeophyceae) found primarily in tropical marine waters. It generally grows on rocky substrates. In tropical Turbinaria species that are often preferentially consumed by herbivorous fishes and echinoids, there is a relatively low level of phenolics and tannins.
Halimeda tuna is a species of calcareous green seaweed in the order Bryopsidales. It is found on reefs in the Atlantic Ocean, the Indo-Pacific region and the Mediterranean Sea. Halimeda tuna is the type species of the genus Halimeda and the type locality is the Mediterranean Sea. The specific name "tuna" comes from the Taíno language, meaning "cactus" and referring to the resemblance of the thallus to the growth form of an Opuntia cactus.
Bangia is an extant genus of division Rhodophyta that grows in marine or freshwater habitats. Bangia has small thalli with rapid growth and high reproductive output, and exhibits behavior characteristic of r-selected species. The plants are attached by down-growing rhizoids, usually in dense purple-black to rust-colored clumps. The chloroplasts of Bangia, like others in the division Rhodophyta, contain chlorophyll a and sometimes chlorophyll d, as well as accessory pigments such as phycobilin pigments and xanthophylls. Depending on the relative proportions of these pigments and the light conditions, the overall color of the plant can range from green to red to purple to grey; however, the red pigment, phycoerythrin, is usually dominant.
Amphiroa is a genus of thalloid red algae under the family Corallinaceae.
Codium fragile, known commonly as green sea fingers, dead man's fingers, felty fingers, forked felt-alga, stag seaweed, sponge seaweed, green sponge, green fleece, sea staghorn, and oyster thief, is a species of seaweed in the family Codiaceae. It originates in the Pacific Ocean near Japan and has become an invasive species on the coasts of the Northern Atlantic Ocean.
Jania is a genus of red macroalgae with hard, calcareous, branching skeletons in the family Corallinaceae.
Laurencia is a genus of red algae that grow in temperate and tropical shore areas, in littoral to sublittoral habitats, at depths up to 65 m (213 ft).
Blidingia minima is a species of seaweed in the Kornmanniaceae family. It was described by Johann Kylin in 1947.
Hypnea is a genus of red algae, and a well known carrageenophyte.
Dictyota is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of 2017, some 237 different diterpenes had been identified from across the genus.