Codium is a type of green macroalgae, also known as Seaweed, that belongs to the order Bryopsidales. The name comes from a Greek word related to its soft texture.
Paul Claude Silva, a professor at the University of California, Berkeley, was a leading expert on Codium taxonomy.
He described 36 species of Codium, and one of them, C. silvae, was named in his honor.
What Is the Taxonomy and Nomenclature of Codium?
Codium is the largest member of the algal family Codiaceae, which is part of the order Bryopsidales.
There are currently about 143 confirmed species and four unresolved members.
The type species of Codium is C. tomentosum. Unfortunately, there were some taxonomic errors made by Stackhouse when he failed to provide holotype specimens for C. tomentosum and some other species.
P.C. Silva later corrected these mistakes by establishing neotypes for each species and clarifying the differences between C. tomentosum, C. fragile, and C. vermilara.
What Is the Morphology of Codium?
Codium has a unique structure that is made up of a single, multinucleated, branched, tubular cell called a siphon. The siphons end in a swollen part called the utricle.
The siphons intertwine to form a mesh-like center called the medulla, and the utricles surround this layer to form a green to a dark-green outer layer called the cortex.
There are three main forms of Codium thalli:
- Mat-forming: The thalli encrust and adhere to a substrate using medullary filaments.
- Spherical: The thalli form a ball and attach to an area using rhizoidal filaments.
- Erect thalli: These are typically dichotomously branched with the medulla surrounded by utricles.
The utricles that form the thallus can also have a variety of shapes and thicknesses, mostly based on their apical wall thickness and apex shapes.
Like many seaweed species, Codium exhibits a wide range of morphological plasticity, which has made taxonomy based on morphology challenging.
Where Is Codium Found?
Codium is found in tropical to temperate areas, but it’s not found in the frigid polar regions. In Ireland, two species, Codium adhaerens and Codium bursa, are very rare.
Codium adhaerens has been recorded on the west and north coasts, while Codium bursa has been found in Mulroy Bay and near Belfast.
Worldwide, Codium species have been found in countries such as Australia, New Zealand, the United States, Canada, South Africa, and countries in Europe.
However, some species have managed to invade other areas through marine traffic, causing biodiversity and aquacultural losses.
One example is C. fragile spp. tomentosoides, also known as the ‘oyster thief,’ which has spread from Japan to Europe and the United States.
What Is the Ecology of Codium?
Codium is found in both the intertidal zone and the subtidal area.
It has a diplontic life history, meaning that the dominant diploid (2N) thallus produces male and female gametangia that produce haploid (N) gametes through meiosis.
Codium can also reproduce through fragmentation, which has contributed to its spread across the globe.
How Is Codium Exploited, Harvested, and Cultivated?
South Korea is the world’s largest consumer and producer of farmed Codium, which is known as Cheonggak in South Korea.
In 2017, they produced about 4000 metric tons of fresh weight, valued at 2 million US dollars.
Farming and cultivation involve seeding a rope line with isolated pieces of utricles and medullary filaments and transferring it to the open sea for grow-out cultivation.
What Are the Chemical Properties and Uses of Codium?
Research on the bioactivity of Codium has shown that its polysaccharides, glycoproteins, galactans, anionic macromolecules, and other extracts have various uses.
They can be used as immunostimulatory, anticoagulant, anticancer, anti-inflammatory, antibacterial, antifungal, and antiviral agents.
How Is Codium Utilized and Managed?
Codium can be eaten fresh or dried and is typically cooked and seasoned with soy sauce and vinegar or mixed with kimchi.
Its various chemical properties make it a valuable resource for both food and medicine.
Codium Characteristics
| Care Level: | Easy |
| Growth Rate: | Slow |
| Nutrient Uptake: | Fair |
| Required Lighting: | Moderate High |
| Required Water Flow: | High |
| Is Palatable? | No |
| Maximum Size: | 12 in (30.5 cm) |
Scientific Classification
| Kingdom: | Plantae |
| Order: | Bryopsidales |
| Family: | Codiaceae |
| Genus: | Codium |
| Scientific Name: | Codium |
| Conservation Status: | Unknown |