Red Tide and Sargassum Shake Things Up in Yucatan

Ah, the azure waters of the Yucatan coast, a tropical paradise that conjures images of swaying palm trees and pristine beaches. However, beneath the idyllic surface lies a tale of two aquatic adversaries: the notorious red tide and the less worrisome sargassum invasion. In this article, we dive deep into the oceanic realm to explore the nuances of these natural phenomena and shed light on the current situation facing the Yucatan Peninsula.

If you've ever heard locals mention the infamous "red tide," you might have wondered what it actually means. Well, it turns out that these crimson-colored blooms of algae have been a recurring concern along the Yucatan coast since as far back as 1948. Eduardo Batllori Sampedro, a distinguished researcher at the Centro de Investigación y de Estudios Avanzados del IPN in Mérida, reveals that the most significant red tide events occurred in 2001, 2003, and 2008.

Over the years, a total of 15 harmful algal species have made their presence felt in the region, but recent events have brought about three particularly tenacious species that have lingered for weeks on end. Covering an expansive area of 5,000 to 10,000 square kilometers, these stubborn blooms contain densities of six to 12 million cells per liter, dwarfing the usual count of just a few thousand cells under normal conditions.

As these menacing red tides encroach upon the coastline, their impact on the local marine ecosystem becomes evident. Last year, the Yucatecan coast witnessed a significant presence of the menacing "red marea" (as the locals call it). Alarming reports from Cinvestav revealed that algal blooms persisted from July to August, resulting in the unfortunate discovery of numerous deceased marine species washing ashore. The Ministry of Health, in response to this unsettling phenomenon, advised against consuming these stranded animals to avoid potential health risks.

In the grand aquatic drama unfolding off the Yucatan Peninsula, sargassum plays a supporting role—though not entirely devoid of significance. Unlike its flamboyant counterpart, the red tide, sargassum has not yet reached worrisome levels in Yucatan. Eduardo Batllori Sampedro clarifies that while neighboring Quintana Roo faces massive accumulations of the brown seaweed, Yucatan experiences a dispersed presence of sargassum on its platform. The fluctuating currents, propelled by trade winds and the changing tides, contribute to the movement and distribution of sargassum across the Yucatecan waters.

The Tides of Change

As the seasons change and the Caribbean currents accelerate, a fascinating phenomenon occurs—an upwelling of nutrients from the ocean depths. This surge in nutrients fuels the growth of various biological blooms, triggering both the sargassum proliferation and the red tide. With the weakening of the northerlies, these currents transform into conduits of life-giving sustenance, yet they also set the stage for potential algae troubles.

In the ever-shifting maritime landscape, it would be wise to remain vigilant regarding the sargassum invasion. However, it is the red tide that demands our utmost attention. Although the Yucatan Peninsula has yet to experience a significant surge in sargassum, the risk of red tide outbreaks looms large. The period from May to September is the prime season for the formation of large, sticky patches that can cling to the coastline, fueled by the southeast winds.

As you tread the shores of the Yucatan, let this article serve as your guide to the perplexing world of red tides and sargassum invasions. While sargassum may presently be a mere annoyance, the red tide poses a more imminent threat to the delicate balance of marine life in the region. Stay informed, heed the warnings of the authorities, and let us collectively protect the stunning biodiversity that thrives beneath the sun-kissed waves of this cherished coastal haven.

What is red tide?

Red tide is a term used to describe events in which the water turns certain colors due to a high concentration of marine algae. However, not all red tides are harmful. Some toxic or harmful events can occur without changes in water color but still have enough toxins to pose a risk.

How does red tide affect human health?

Red tide poisoning can affect the nervous, respiratory, and digestive systems, leading to symptoms like amnesia, respiratory arrest (in severe cases), diarrhea, and paralysis of extremities. Certain microalgae produce potent toxins, which can accumulate in mollusks and gastropods that feed on them. Consuming contaminated shellfish can cause intoxication, with the severity depending on the toxin type and dose. Cooking, adding vinegar or lemon, or consuming alcohol does not inactivate the toxins, and there are no antidotes. Annually, there are over 2,000 reported cases of human poisonings associated with red tide, with a 15% mortality rate.

How to prevent red tide intoxications?

To avoid health risks:

• Avoid collecting mollusks and shellfish from beaches for home consumption.
• Follow provisions, ordinances, and public notices regarding shellfish extraction and consumption restrictions.
• Do not buy seafood preparations from unauthorized vendors.
• Only purchase shellfish with proper health certificates from authorized fishmongers, restaurants, or food stores.

What to do in case of red tide poisoning?

In case of intoxication from consuming two-shell mollusks contaminated by red tide, such as clams, oysters, mussels, and scallops, it is essential to seek immediate medical attention.

Frequency of occurrence

Harmful algal blooms (HABs) occur in various forms and have multiple impacts. The most significant impact is when toxic phytoplankton is consumed by filter-feeding bivalve mollusks, leading to the accumulation of algal toxins that can cause poisoning symptoms in humans.

It's worth noting that other organisms in the food chain, such as certain gastropods, can also transfer biotoxins produced by these algae. The severity of intoxication depends on the predominant species causing it. In Mexico, about 157 algae species have been identified, of which only 45 are potentially toxic.

How are mollusks contaminated?

Mollusks can become contaminated due to changes in climatic conditions or an increase in nutrients in the ocean, which promotes the rapid reproduction of toxin-producing microorganisms.

During a red tide alert, authorities provide the following recommendations:

• Report any changes in the color of marine waters to the authorities.
• Pay attention to official information disseminated.
• Avoid consuming mollusks during the alert.
• If a red warning flag is raised, refrain from swimming and bury dead fish found on the beaches to prevent contamination.