SARGASSUM: CHARACTERISTICS, TAXONOMY, REPRODUCTION, BENEFITS - BIOLOGY - 2025

The Sargasso (Sargassum) is a genus of perennial and floating macroalgae belonging to the family of the Fucales Sargassaceae order. The name sargasso derives from the Portuguese "sargasso" which translates as "grapes", alluding to the air vesicles on its surface.

This genus is essentially made up of the species S. natans and S. fluitans that seasonally renew their abundant branches. They are photosynthetic organisms capable of synthesizing their own food and completing their life cycle from sunlight and inorganic substances.

Sargassum natans. Source: James St. John

Pelagic sargassum is a brown algae that floats freely on the surface of the oceans and never goes down to the seabed. In fact, these free-living algae are only found floating in the Atlantic Ocean, being characteristic of the famous "Sargasso Sea".

In its environment, it constitutes a particular ecosystem for various marine species, providing shelter and food for fish, crabs, shrimp and turtles. Certain factors such as the increase in water temperature or nutrients, marine currents and winds favor their reproduction and invasion in coastal areas.

General characteristics

Morphology

The body of the alga or thallus has an extensively branched tree shape with a leathery texture. In addition, it has numerous lanceolate leaves, with a prominent central rib and several main axes.

The thallus, with an acute and fungal aspect, of a few centimeters or more than one meter, is yellowish-brown in color. At the base of each leaf, spherical vesicles or aerocysts of parenchymal material develop that contain air or other gases that favor their flotation.

Habitat

Sargassum is found in warm, temperate or tropical marine environments, being found along the low tide line. It is a common species around the coasts, being easy to see from a few meters to 30-50 m deep.

Sargassum vulgare is the most representative species of the genus. It contains numerous air vesicles on its surface, thus forming floating tangles on the surface. In fact, ships tend to slow down due to the accumulation of sargassum in the middle of the ocean.

Sargassum invasion on Mexican beaches. Source: pixabay.com

Chemical composition

Sargassum flour has been used as a nutritional supplement for laying hens, optimizing egg quality and reducing the percentage of cholesterol. Likewise, it has been used as feed for sheep, improving their metabolic level and increasing the productivity values ​​of these species.

In this regard, the flour of Sargassum spp. It contains various percentages of inorganic materials and carbohydrates of nutritional interest. Among the elements with the highest concentration are sodium, potassium, calcium and magnesium, as well as traces of copper, iron and zinc.

The presence of omega 3 fatty acid and high concentrations of vitamin C and retinol are also common. In addition, it is a source of various amino acids, such as lysine, tyrosine, phenylalanine, threonine, asparagine and glutamine.

Taxonomy

- Kingdom: Chromista.

- Phylum: Heterokontophyta.

- Class: Phaeophyceae.

- Order: Fucales.

- Family: Sargassaceae.

- Genus: Sargassum.

Species

Sargassum detail. Source: Jonathan Wilkins

Reproduction

The fruiting body of Sargassum is made up of a sporophyte, which is the diploid multicellular stage in the life cycle of this alga. However, this organism does not multiply asexually by spores, but reproduces vegetatively or through sexual organs.

Indeed, in the formation of new individuals, the combination of the process of sexual reproduction, through gametes, and asexual reproduction occurs. Asexual reproduction is a fast process that limits diversity, and on the contrary, the slower sexual process allows increasing genetic diversity.

Vegetative reproduction by fragmentation is the usual form of reproduction for free and floating sargassum species. On the other hand, sexual reproduction is oogamic and consists of the fusion of a smaller male zoogamete with a larger female gamete.

In oogamic reproduction, the gametophytes are female or male, promoting the respective formation of ovules or sperm. Zoogametes or spermatozoa are biflagellates of the mastigonemate type, that is, with two flagella: one towards the front and the other towards the rear.

The fusion of the gametes occurs in the ovagina or female germ cell, which will give rise to the oocyte and finally the egg will develop. In this case, the zygote arises in response to certain conditions of temperature and light.

In Sargassum the cycle is monogenetic, since only one generation occurs. In fact, the zygote gives rise directly to the new gametocytes, closing the cycle, without the need to produce spores.

Benefits

Algae are an abundant, inexpensive and interesting resource to use as an ingredient in food or food supplement. In fact, it is an ingredient that provides bioactive and nutritional compounds, and also has special properties that favor its use as a raw material.

Sargassum. Source: Ocean Explorer / NOAA

Industrial

Brown algae, including Sargassum, contain alginate, an anionic polysaccharide widely present in their cell walls. For an algae to be considered commercial it must have 20% of its dry weight as alginate.

Alginates are used in the pharmaceutical industry, as food thickeners, and in the textile industry as fabric dyes. In the process of obtaining alginates, the application of calcium salt is necessary to develop the alginate gel required for the various branches of production.

Medicinal

Sargassum has been used by traditional Chinese medicine since ancient times. Its high content of iodine and bromine, as well as salts in the form of iodides and bromides are very useful for the treatment of thyroid disorders.

Indeed, its main use is for the treatment of goiter or increases in the size of the thyroid gland. The use of the brown seaweed Sargassum is a common reference among artisanal treatments to alleviate this disease.

In the same way, it is used for the treatment of other thyroid complaints, such as chronic thyroiditis or Hashimoto's disease. In addition, it is recommended as a diuretic by increasing urine production, as a vermifuge, resolutive and to mitigate edema.

Its topical application allows to relieve the pain of testicular hernias and inflammation. On the other hand, combined with other medicinal herbs such as chestnut, it can alleviate the chronic disease of the respiratory system called silicosis.

Organic fertilizers

With the algae collected from the banks, a liquid fertilizer with a high content of organic elements can be made. Its application in fruit species has allowed to increase flowering and fruiting, obtaining abundant and healthy harvests.

References

1. Báez, José C. (2018) Sargassum vulgare. Coastal Species of the Province of Malaga.
2. Carrillo, S., Bahena, A., Casas, M., Carranco, ME, Calvo, CC, Ávila, E., & Pérez-Gil, F. (2012). Sargassum spp. as an alternative to reduce the cholesterol content in the egg. Cuban Journal of Agricultural Science, 46 (2).
3. Casas-Valdez, M, Hernández-Contreras, H, Marín-Álvarez, A, Águila-Ramírez, RN, Hernández-Guerrero, CJ, Sánchez-Rodríguez, I, & Carrillo-Domínguez, S. (2006). Sargassum seaweed (Sargassaceae): a tropical alternative for feeding goats. Journal of Tropical Biology, 54 (1), 83-92.
4. Romero Zarco, C. (2017) Brown algae (Div. Feofitas) Department of Plant Biology and Ecology, University of Seville. Recovered at: personal.us.es
5. Sargassum. (2019, May 30). Wikipedia, The Free Encyclopedia. Recovered at: es.wikipedia.org
6. Uses of sargassum (2017) Sargassum and its reactions in the human body. Recovered in: sargazo-y-el-ser-humano.blogspot.com
7. What is Sargassum (2017) NOAA Ocean Explorer. Recovered at: oceanexplorer.noaa.gov