MACROCYSTIS PYRIFERA: CHARACTERISTICS, TAXONOMY, LIFE CYCLE - BIOLOGY - 2024

The Macrocystis Pyrifera is a macroalgae belonging to the class Phaeophyceae (brown algae). It is one of the largest algae on the planet, having a predilection for cold-water marine habitats.

It was described for the first time by the Swedish botanist Carl Adolph Agardh in 1820. It is an algae that forms true marine forests, in which it serves as sustenance for various species of aquatic animals.

Macrocystis pyrifera. Source: By Claire Fackler, CINMS, NOAA. (NOAA Photo Library: sanc0058), via Wikimedia Commons However, they can also be the cause of some unfortunate incidents, as they are so abundant that they can become entangled in the thrusters of boats.

This macroalgae is one of those that brings the greatest amount of benefits to human beings. For its applications in gastronomy, ecology and in the health field, it has earned a well-deserved place of honor.

However, many aspects of Macrocystis pyrifera remain unknown. This is why studies on its properties have multiplied in recent years.

This alga is expected to become one of the best natural allies of man when it comes to caring for health and the planet.

Taxonomy

The taxonomic classification of Macrocystis pyrifera is as follows:

Domain: Eukarya

Kingdom: Protista

Phylum: Heterokontophyta

Class: Phaeophyceae

Order: Laminariales

Family: Laminariaceae

Genus: Macrocystis

Species: Macrocystis pyrifera

Morphology

Macrocystis pyrifera is one of the largest algae known, which is why it is established that they are multicellular organisms. It has even been classified as the longest aquatic living being, since despite its average size being 30 meters, specimens have been found that reach a length of between 50 and 70 meters.

In the same way, it is an alga whose growth is quite active. According to various studies, it has been established that it grows an average of 12 cm per day.

Morphologically speaking, the alga is composed of a fixation structure, known as a rhizoid, which can be up to 40cm in diameter and a total of 38cm in height. Its stipes (stem pedicle) are quite long and cylindrical in shape.

Blades arise from the stipes, which are rough with certain serrated edges. The sheets that are far from the base have structures known as pneumatophores, which fill with air and allow the algae to float.

The characteristic color of these algae covers a spectrum that goes from yellow to brown, passing through greenish brown.

General characteristics

Habitat

These algae are distributed throughout the globe, having a predilection for low-temperature waters, with an average of 21 ° C.

They are located on almost every continent. On the American continent it is found in South America and North America (from California to Alaska); in Africa it is particularly abundant in South Africa; in Oceania it can be found in South Australia and New Zealand.

They have pigments

The algae belonging to the species Macrocystis pyrifera present, like all algae, various pigments that provide certain characteristic coloration.

Among the pigments present in this type of algae we can mention xanthophylls such as fucoxanthin (brown color) and flavoxanthin (golden yellow color). There are also two types of chlorophyll, a and c.

Although it is true that xanthophylls are responsible for the coloration of the algae, chlorophyll plays a preponderant role in the photosynthesis process carried out in the algae cells.

Nutrition

Macrocystis pyrifera algae are autotrophic organisms. This means that it is capable of synthesizing its own nutrients and it does so through the process of photosynthesis.

Photosynthesis is one of the fundamental processes for the maintenance of life on the planet. Macrocystis pyrifera can carry out photosynthesis thanks to the fact that it has chlorophyll in its cells, which is responsible for absorbing sunlight, an element also essential for the process to develop optimally.

It is very useful in ecosystems

On the seabed, these algae constitute true forests. Therefore, they are refuge, habitat and food for a large number of species of fish and invertebrates. They can also be substrates for other types of algae.

Macrocystis pyrifera is sustenance and refuge for many species of fish. Source: By Stef Maruch (kelp-forest.jpg), via Wikimedia Commons

In the same way, thanks to their photosynthetic activity, they are considered primary producers of great importance within the ecosystem. For this reason, they are responsible for the fixation of large amounts of carbon.

Reproduction

These algae manifest the two types of reproduction that exist: asexual and sexual.

Asexual reproduction is given by the production of spores, known as zoospores, while sexual reproduction occurs by the union and fertilization of a female gamete by a male gamete.

Lifecycle

This type of algae has a life cycle in which alternation of heteromorphic generations is appreciated: the sporophyte and the gametophyte. The sporophyte (diploid) constitutes the visible macroscopic plant, while the gametophyte (haploid) is microscopic in size.

Taking as a starting point the diploid sporophyte, when it has reached an approximate age of between six and twelve months, it produces the zoospores.

These zoospores are stored in a structure known as sporophils. They are the product of numerous meiotic divisions, so, genetically speaking, they are haploid.

Zoospores are released from the sporophils, which settle on the rocky substrate in which they inevitably germinate. Through numerous successive mitotic divisions, the spores generate gametophytes (female and male) that are microscopic in size.

The male gametophyte generates biflagellate and mobile cells called anterozoids. The female gametophyte generates the ovum, which is immobile.

Once the fertilization or union of the male and female sex cells occurs, a zygote is generated that is diploid. It develops gradually and grows through a large number of mitotic divisions. At four weeks, small 1-2mm blades can be seen.

Two months after fertilization, the sporophyte is fully visible, reaching a length of between 5 and 10 cm. Over time, the sporophyte continues to undergo mitosis divisions, growing and becoming apparent. At 12 months the algae can already reach a length of 20 m.

Once fully developed, the sporophyte is able to produce more zoospores, thus completing the cycle and starting a new one.

Applications

Macrocystis pyrifera is one of the algae that has the greatest number of uses for human benefits. The versatility of this alga has allowed it to be used in various fields such as pharmacology, the environment and the food industry.

Pharmacological uses

This species of brown algae has been very useful in the field of pharmacology. It is an abundant source of agar, which can be used in the preparation of some medicines.

First of all, agar has certain properties that allow the body to cleanse. It is an excellent cleanser and laxative. These properties are due to the fact that agar stimulates intestinal transit. It is beneficial because in addition to this, it does not cause the discomfort (colic, abdominal cramps) that other laxatives do.

Likewise, this property is also related to a decrease in cholesterol and triglycerides, since it accelerates the passage of these compounds through the intestine, preventing them from being fully absorbed and passing into the bloodstream.

Similarly, numerous studies have shown that certain components obtained from this algae contribute to controlling diabetes, since it slows the absorption of glucose by intestinal cells.

Other studies that are still in the experimental phase have determined that some compounds that are extracted from these algae, known as fulcans and sulfated galactans, have anticoagulant action.

Its long-term effects have yet to be determined. If proven to be safe, they would be a great advance in the treatment of certain pathologies of the cardiovascular system.

Uses in the food industry

Agar that is extracted from various algae, including Macrocystis pyrifera, has been widely used in the gastronomic area.

One of the uses that they are given is in the preparation of desserts such as jellies. It is used thanks to its gelling effect and because it is tasteless, which does not interfere with the taste of desserts and foods to be prepared.

Likewise, another compound extracted from these algae, alginic acid, is widely used as an emulsifier and thickener in certain foods widely used by the entire population. These include sauces, salad dressings, and baby food, among others.

In addition to this, the seaweed itself is used in various international cooking recipes. Particularly in Peru and Chile they are part of many dishes.

Ecological use

Macrocystis pyrifera contains in its composition a large amount of sugars. In fact, they make up over 60% of your full weight. Well, advances in biotechnology have made it possible to obtain forms of fuels through the processing of organic compounds.

In this case, the carbohydrates that are contained in Macrocystis pyrifera are processed and fermented to convert them into a biofuel known as ethanol. It can also be transformed into other types of biofuel.

This is of great importance at an environmental level, since when using biofuels the emission of toxic gases into the atmosphere, as a result of combustion, is greatly reduced.

References

1. Alveal, K., Romo, H. & Avila, M. (1982). Study of the life cycle of Macrocystis pyrifera from Isla Navarino, Chile. Bot. 39: 1-12.
2. A. Jackson, "Modeling the growth and harvest yield of the giant kelp Macrocystis pyrifera", Institute of Marine Resources, Scripps Institution of Oceanography, University of California, San Diego, Marine Biology 95 (611-624), 1987
3. Mondragon, Jennifer & Jeff Mondragon. (2003) Seaweeds of the Pacific Coast. Monterey, California: Sea Challengers
4. North, WJ, GA Jackson, & SL Manley. (1986) "Macrocystis and its environment, knowns and unknowns." Aquatic Biology 26: 9-26
5. Ríos, C. and Mutschke, E. (2009). Contribution to the knowledge of Macrocystis pyrifera: bibliographic review on the “huriales” distributed in the Magallanes region. Annals Instituto Paragonia. 37 (1). 97-102.