Sargassum in Mexico

Seaweed in the Caribbean, a new reality.

Adam Duffy · 1 August 2019

Is seaweed on all the beaches in Mexico? When is the perfect time to go to the beach in Mexico? As usual, traveling is not a bad idea, and the beach is always an excellent option to cool off. However, if you have traveled to the beach lately, you may have noticed piles of seaweed stacked on the coastline and a smell like rotten eggs. The past few years during the summer months, the east-facing coasts in the Carribean have been overwhelmed by sargassum. If you are curious to know more about when and where and what sargassum is, then you have come to the perfect place. We will try to answer the different and most common questions you can ask about sargassum in Mexico.


What is it?

    Sargassum is a particular type of brown seaweed possibly originating from the coasts of Africa, despite its origin large groups of this can easily be found in the Atlantic, specifically in an area of waters that bears the name "the sea of sargassum" such a title derives from the fact that a vast region of the North Atlantic has an exorbitant concentration of this type of algae, it is characterized by being free-floating seaweed and not being tied to the seafloor; its anatomy is composed by different leafy structures and by a significant quantity of elements similar to berries called pneumatocysts, these are mainly full of oxygen, and they are in charge of providing to the seaweed as much a high level of buoyancy as its characteristic appearance.

    Perhaps you will be able to appreciate such seaweed in some vacations that you have spent in the Caribbean or Mexico, because for years’ large quantities of sargassum appear somewhat sporadically in Playa del Carmen, Tulum, most of the Mayan Riviera and most of the Caribbean islands, however, the impact that such seaweed has in each of these places is very different (in some areas tends to be worse than in others).


Where it's being affected the most

    Since the sporadic and massive (literally massive) appearance of sargassum in different locations from late 2011, many of the beaches belonging to islands and coasts bordering the Caribbean are saturated with it, for example large quantities of sargassum have appeared in Playa del Carmen, in Cancun and so many other tourist sites to the point that they have accumulated on the shores of the beaches preventing beachgoers from entering what once was a beautiful blue sea and considerably damaging the landscape.

    In spite of all the above you should not worry, because not all beaches in the Caribbean or the gulf must deal with the constant and sudden appearance of such annoying seaweed, because only beaches that have certain chemical or climatic conditions are an excellent home for the sargassum, because of it some coasts of Barbados, Curacao, Dominican Republic, Trinidad and Tobago, Florida, Alabama, Texas, New Orleans, as well as so many other islands or the Caribbean Sea have really been affected by the excessive presence of seaweed, however it is necessary to highlight the fact that there are locations that are entirely free of sargassum. The trick is finding a west-facing coast. Since the sargassum is coming from the open ocean and travels west, the east-facing coasts will receive all the sargassum. So islands off the Mexican Riviera are a life hack on avoiding sargassum. Consider Cozumel or Isla Mujeres when you’re planning your next Mexican Riviera vacation. These islands west coast have dodged a bullet. Allowing them to maintain their characteristics and beautiful blue water beaches which have been a significant tourist focus for many years.


Why it's here?

    As explained in the previous section, the sargassum tends to frequent beaches that provide certain favorable chemical conditions, as it can settle on them, feed and grow relatively calmly, at least until it is dragged to the shore by the rising tides (because there it begins to decompose and its smell could be a little annoying).

    The frequent appearance of sargassum in the Caribbean and in the Gulf of Mexico is due to the fact that most of the beaches in such geographical regions have excellent conditions in terms of temperature, which allow the sargassum to feed and reproduce quickly and simply once it has come into direct contact with such waters, since the sargassum has an unusual method of reproduction that allows it to expand on its own, which makes it really difficult to eliminate it once it has spent a lot of time on the beach.


How it gets here?

    In reality the transport method used by the sargassum is a bit mysterious because although it is estimated that it is transported from one place to another when it is washed away by sea currents or by the strong winds of storms, the large amount of seaweed that appears on the coasts and the frequency with which it does so (which can easily scratch the absurd) has led more than one to question the speed at which seaweed is transported, for although sea currents may take it to genuinely uncertain destinations the imsma often settles very punctually to the north of the Pacific Ocean in the already mentioned "Sea of Sargassum", and then be dragged in small quantities to different points of the Caribbean Sea and the Gulf of Mexico, where it will reproduce to create large groups capable of providing the right level of problems to tourists who frequent such areas as well as fish, shellfish and turtles living in them this is due to the fact that it is an invasive species, capable of significantly deteriorating some natural processes developed in the different ecosystems to which it is integrated.


Where it comes from?

    It is not known precisely where the seaweed originates, however (and from the above) it is estimated that the plant originates from the coasts of Africa and that it is later concentrated in different specific points of the Atlantic Ocean once it is transported by sea currents as well as storms and winds, one of these points of concentration is the well-known "sea of the sargassum" it is emphasized that the site is "known" by the fact that it is alluded to in different literary works, an extension of waters of approximately 1,100 km wide by 3,200 km long, in which there is an incredible amount of masses of sargassum, such a region despite being called sea, does not have any type of limitation understood by land, but instead is delimited in its 4 cardinal points by the currents of gulf stream, north atlantic, canary, and north atlantic equatorial which limit it in the west, north, east and south respectively, Because of these conditions, it is estimated that this is the main origin of the large quantity of sargassum that is housed almost massively in the Gulf of Mexico, where it is transported by winds and currents to the south of North America, especially to Alabama and Florida and the different Caribbean islands.


The good and bad of it 

    Not everything related to sargassum is negative, starting from this it is possible to say that the existence of sargassum is not entirely harmful to the environment, in fact, it is usually beneficial for some environments, given that it is generally used as a refuge for different species that somehow or other have converted large areas of this in their natural habitat, on the other hand, the seaweed represents an essential source of nutrients for all those species that despite not developing their lives in it, usually use it as their primary source of food.

    On the other hand the sargassum in the right measure is able to provide exciting contributions to the beaches in which it concentrates, because it usually anchors the sand satisfactorily to encourage the creation of dunes and thanks to the enormous amount of nutrients available, works as an excellent fertilizer for a large number of plants, also such nutrients have prompted a significant number of companies to carry out different studies in order to evidence the possible medicinal faculties and even energy as biofuel of seaweed.

    Although the different benefits that sargassum can bring to both nature and humanity have been exposed, it is necessary to emphasize that the massive appearance of sargassum in cancun, and in so many other areas where coral reefs are located, can be genuinely detrimental to both fully submarine algae species and to the fish and animals that inhabit the area, as large tracts of algae are often able to hinder the sun rays that are extremely necessary for other specimens to carry out the photosynthesis process and obtain important basic nutrients that only these provide, coupled with this when seaweed is massively present in such environments it tends to absorb most of the oxygen present in the water thus creating an overload of carbon dioxide that settles in the ocean, causing different species of marine animals to die of suffocation, but this does not end there, as the lack of oxygen also produces a substantial increase in the acid levels of the pH of the sea, event that while it is not capable of directly hurting humans, it is capable of directly attacking the life of different shellfish endemic to a given area because its exterior shell is composed mainly of calcium, and the same can be dissolved easily due to high levels of acidity. 

    The sargassum not only directly affects the invaded ecosystem, because when it occurs in large quantities it is usually pushed by the waves to the beach, where it piles up and eventually decomposes, during its decomposition process the seaweed emits a strong odor capable of producing a human, nausea, dizziness and severe headaches, It is because of this that large concentrations of seaweed on a coast or in a given geographical region can be detrimental to the performance of specific economic activities such as tourism because tourists prefer to avoid environments saturated with sargassum since they tend to be unattractive and have a terrible smell. Also fishing activity is impaired since sargassum tends to significantly deteriorate the engines of boats and the various tools used by fishermen, It is, therefore, vital for the authorities of all those geographical regions that tend to become saturated with sargassum to design efficient measures that allow them to deal with seaweed without significantly harming the environment each time it is incorporated into the environment.


When it's the worst?

    As mentioned above, the sargassum usually settles very often along the Gulf of Mexico and the Caribbean since its first massive appearance in mid-2011, because of this different experts conducted research and concluded that the seaweed appears more frequently in summer because in such a season are increased air currents (which together with sea currents) that are responsible for transporting the sargassum to most of the east coast of the American continent.


How is doing what about it?

    The University of Florida, in conjunction with the UNAM and some other organizations, has made the publication of various documents aimed at clarifying doubts about sargassum and encourage the development of manual harvesting processes of seaweed, in order to avoid deteriorating the ecosystem through the use of heavy machinery, On the other hand, these documents also propose different procedures and uses designed to address the crisis of sargassum in a "advantageous" manner, through the efficient integration of both governmental and non-governmental entities (private companies) in order to give useful use to sargassum in different areas that could take advantage of the large amount of nutrients in the seaweed; On the other hand, the organization seeks to monitor through reports and photos published by tourists and other organizations the number and location of beaches affected by this phenomenon in order to keep a competent record of the regions affected by the massive appearance of sargassum.


Check out Dive Into Life's article about sargassum in the area here


  1. Básicas y diferentes generalidades relacionadas con el sagassum.

  2. Sargassum the what, where and why of this seaweed. Principales sitios y costas afectadas por el sargassum, principales periodos en los cuales tal seaweed aparece

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