Mexico : Norma Muñoz: “La gente no está informada de los efectos del sargazo, dice que las afectaciones las mandó Dios”

La coordinadora del Centro Interdisciplinario de Investigaciones del Instituto Politécnico de México lidera una investigación sobre los efectos en la salud de la macroalga

La coordinadora del Centro Interdisciplinario de Investigaciones del Instituto Politécnico de México, Norma P. Muñoz, en una foto de archivo. CORTESÍA NORMA P MUÑOZ

Los pobladores de Punta Allen se mantienen ajenos al acontecer del mundo. El pueblo de pescadores de apenas 400 habitantes se ubica en el extremo sur de la Riviera Maya, en el Estado de Quintana Roo, escondido en la reserva de la biosfera de Sian Ka’an, México. Además del difícil acceso por la falta de caminos pavimentados, la localidad no tiene señal para celular, y cuenta con electricidad solo a ciertas horas del día. No hubo contagios de covid, pero tampoco tenían cómo saber que los mareos, cansancio, ardor en los pies y ojos que sufren algunos pescadores son los efectos de convivir con el sargazo que arriba a las playas cada vez en una mayor cantidad.

Se enteraron recientemente cuando un grupo de investigadores arribó al lugar. Norma Patricia Muñoz Sevilla, coordinadora del Centro Interdisciplinario de Investigaciones y Estudios sobre Medio Ambiente y Desarrollo del Instituto Politécnico Nacional de México y su equipo los entrevistaron como parte de los estudios que hacen sobre el impacto ambiental del sargazo y sus efectos en la salud pública. “La gente no está informada y dice que las afectaciones que tiene las mandó Dios”, dice Muñoz.

El fenómeno también ha destruido sus bienes. “Hay un efecto corrosivo de los gases (ácido sulfhídrico, amoniaco y metano) que ha averiado sus aparatos electrónicos, refrigeradores, televisiones y teléfonos”, advierte. Tras más de 150 entrevistas a lo largo de la costa del Estado, no tiene dudas sobre los efectos de esa marea parda en la salud de la población, sobre todo de quienes tienen contacto directo con ella. “Ya no es que creamos que los está afectando, es así”, dice en entrevista con América Futura.

Un turista camina sobre una playa cubierta de sargazo, en Cancún, el 5 de abril de 2022. ALONSO CUPUL (EFE)

El sargazo es una macroalga cuya proliferación comenzó a sentirse en 2011 llegó en el Caribe mexicano, el extremo este de la península de Yucatán. Desde 2015 no ha dejado de arribar. Según la Secretaría de Ecología y Medio Ambiente de Quintana Roo, llegan unas 200.000 toneladas al año, con impactos negativos para el ambiente, las playas y el turismo. “Es un problema económico, ambiental y también de salud pública”, afirma Muñoz Sevilla.

Pregunta. ¿Cómo llega el sargazo al Caribe mexicano de manera creciente?

Respuesta. Es una especie viva que se reproduce en su camino y se nutre en el océano Atlántico, en la costa oeste de África, luego llega a la costa este de Sudamérica y posteriormente al Caribe. Cuando llega a la desembocadura de los grandes ríos, como el Congo, Amazonas y Orinoco, se nutre tremendamente y se duplica. En 10 días, un metro cúbico de sargazo puede convertirse en seis metros cúbicos.

P: ¿Qué relación tiene con el cambio climático?

R: Los modelos conceptuales de cómo se mueve y por qué, nos indican que la superficie del mar ha subido su temperatura. Las corrientes marinas han sufrido cambios en sus direcciones y movimientos en virtud de la contaminación de la masa de agua en el océano. Los vientos tienen una afectación importante también. Todo esto ha logrado que el sargazo se desprenda, se derive hacia el sur del océano Atlántico, pasando el Ecuador.

P: ¿Cómo empiezan a investigar los efectos en la salud?

R: Recientemente cinco países del Caribe ganamos un proyecto para establecer estaciones fijas para monitorear la calidad del aire y poder definir cuáles son las concentraciones de gases que el sargazo provoca. La isla de La Martinica lideró el proyecto, y nos otorgó todos los equipos que instalamos en Quintana Roo en septiembre. Este año también hicimos encuestas y entrevistas a lo largo de la costa con la gente que trabaja en quitarlo.

P: ¿En dónde colocaron los equipos?

R: Abarcamos desde Cancún hasta la frontera con Belice, se instalaron 12 equipos a lo largo de 700 kilómetros.

P: ¿Cuál es la experiencia de la Martinica en este tema?

R: Desde hace cinco años están trabajando con un semáforo que determina en tiempo real la concentración de gases, y cada día envían un boletín informando a su población sobre la calidad del aire para que no se acerquen. Es a lo que aspiramos hacer en el país.

P: ¿A quiénes entrevistaron?

R: Hicimos más de 150 entrevistas desde el sur hasta el norte del Estado, y les preguntamos cuáles eran sus padecimientos. Los sargaceros trabajan para los hoteles o el Gobierno en la orilla de la playa, ocho horas al día, sin protección. Pero no hay forma de que saquen el sargazo de manera constante por lo que se descompone y emite gases a la atmósfera.

P: ¿Qué tipo de gases emanan del sargazo?

R: Ácido sulfhídrico, amoniaco y metano. Cuando llega a la playa deja de ser un recurso natural y se descompone, se convierte en un residuo peligroso.

P: ¿Qué respondían las personas en las entrevistas?

R: Dicen que sienten que se les están quemando los pies, tienen problemas respiratorios, cambian de humor, problemas de la vista, algunos pierden el conocimiento por los gases. En la Martinica los trabajadores (que remueven el sargazo) llevan botas, equipo de protección, máscara, guantes, gorro. Aquí lo hacen sin zapatos, sin guantes, sin cubrebocas, a veces sin playera, porque hace calor.

 

Fuente: El Pais 22/11/2022

 

Mexico : EL SARGAZO NO SE CONVIERTE EN ARENA

Por Iván Penié, Oceanus International

Steven Czitrom, Instituto de Ciencias del Mar y Limnología, UNAM-Año Sabático en
Oceanus International;

y Vivianne Solís, Instituto de Ciencias del Mar y Limnología, UNAM.

Según datos del Instituto de Ingeniería de la UNAM, el sargazo en su estructura posee 90.7% de humedad e incluso una elevada fracción volátil del 82.8%, por lo tanto, uno de los mitos más arraigados al respecto de esta macroalga que inunda las playas de Quintana Roo, al respecto de que “el sargazo se convierte en arena”, es absolutamente falso.

Sin embargo, existen dos hechos contundentes que promueven la confusión:

1. La elevada superficie de contacto del sargazo, dada por su estructura ramificada de tallos, hojas, vesículas y espinas en algunas especies, así como por su gran capacidad de conglomeración, promueven que, sobre todo en condiciones húmedas, queden adheridas y asociadas grandes cantidades de arena que yace en las playas e incluso pequeños granos suspendidos en el aire. Esa adherencia lógicamente se incrementa cuando se revuelve el sargazo húmedo con la arena durante las actividades de limpieza de playas. Por lo tanto, al avanzar el proceso de desecación y descomposición del sargazo, donde una gran parte de su estructura se evapora, quedan en el lugar
las cantidades de arena que estaban adheridas en su estructura.

2. Asociadas a las diferentes especies de sargazo habita una amplia comunidad de invertebrados epífitos (por ejemplo, briozoos, gusanos serpúlidos y algas rojas, entre otros), cuya composición calcárea también promueve la generación de grandes cantidades de carbonatos en el proceso de secado, posterior a la arribazón o retiro del sargazo de las playas.

Es por estas características que una de las funciones ecológicas más importantes del sargazo es, precisamente, la estabilización de las playas; por lo que la principal y más conveniente práctica con relación a la afluencia de sargazo es dejarlo y esparcirlo en la medida de lo posible sobre las propias playas donde arribó. No obstante, y como es sabido, a partir del año 2011 y, en especial, los años 2015, 2018 y el presente 2022, la afluencia de sargazo hacia las playas ha sido muy frecuente y excesiva, con el consecuente impacto ambiental, turístico y económico, lo cual ha promovido el emprendimiento de diversos (e ineficaces) métodos de contención, colecta y retiro del sargazo de las playas.

Uno de los métodos más perjudiciales en el manejo de la macroalga ha sido cavar trincheras en la playa y enterrar el sargazo, motivado por la creencia de que “el sargazo se convierte en arena”, o con fines estéticos, al “quitar la desagradable mancha café de la vista”, lo cual ha causado grandes impactos en los perfiles y estabilidad de las playas. Otra mala práctica es barrer el sargazo sobre la arena y hacer montículos que luego son acarreados con abundante arena; así como priorizar la recolecta de “sargazo viejo”, debido a que en muchas ocasiones es el “sargazo fresco”, el que se acumula por la acción del oleaje sobre el ya emplayado, formando capas que impiden el secado de la macroalga por la acción del Sol.

Las grandes acumulaciones de sargazo que no se retiran de las playas promueven también su erosión, al formar bermas que, en función del viento incidente, la marea y el oleaje, pueden arrastrar grandes volúmenes de sargazo mezclados con la arena conglomerada en dichas bermas. Cabe señalar que cuando el proceso de secado, por los grandes volúmenes no puede ser en capas de poco espesor de sargazo (10 cm o menos), se produce una descomposición húmeda y anaeróbica de la macroalga que genera diversos gases y compuestos lixiviados, que son altamente tóxicos al ambiente y a la salud humana. El cambio de composición y coloración en las arenas,
además, limita su uso posterior para rellenar las propias playas, en especial si estas constituyen sitios de anidación de tortugas marinas

Por lo tanto, entre las principales recomendaciones en el precario manejo actual del sargazo en las playas, estaría tratar de levantar siempre la macroalga que esté “fresca” o recién arribada, directamente desde la orilla del mar hacia las carretillas o vehículos “livianos” que se usan para tal fin. Dispersar el sargazo siempre que haya oportunidad por el espacio disponible, en capas de 10 cm de espesor, para evitar la formación de bermas que contribuyen a los procesos erosivos y permitir su secado al Sol sobre la misma playa.

 

Fuente: UNAM – Mexico 2021

France : Bilan du BRGM : les taux mesurés en arsenic et en chlorure de sodium dépassent les normes imposées

Quant à la chlordécone trouvée, ici, à Viard, elle est issue d’une pollution antérieure des sols bien connue. • ©R. Gadet

Arsenic, chlorure de sodium dépassant les normes sur 80% des sites…Le rapport final du BRGM sur l’impact environnemental des sites de stockages des sargasses est très inquiétant.

C’est certainement le chiffre à retenir de cette étude. 83% des sites expertisés montrent des dépassements en Arsenic, que ce soit dans les eaux ou les sols. Ce metalloïde est extrêmement toxique et les seuils fixés par la réglementation de ce type d’installation de stockage de déchets inertes sont, par exemple, dépassés dans les eaux stagnantes en contact aux Raisins Clairs, à l’Anse Maurice, à l’Anse du Belley ou encore au Cap à Capesterre de Marie-Galante. Les scientifiques du Bureau de recherches géologiques et minières (BRGM) se sont, eux, attachés à mesurer cette eau dans les sols mais aussi dans les eaux stagnantes, les eaux de surface comme les rivières ou les mares, les eaux de mer et les eaux souterraines.

Les quantités les plus importantes d’arsenic ont été trouvées dans les jus de sargasses, les lixiviats : près de 6000 mg/L sur le site de l’Anse Maurice par exemple à Petit-Canal.

Un cocktail délétère qu’il faut à tout prix empêcher de pénétrer les eaux souterraines hors certains sites dont le sol est essentiellement constitué de substrats sableux comme celui du Belley ou de Pont-Pierre aux Saintes n’ont pas pu empêcher la pollution des eaux souterraines qui présentaient donc des valeurs importantes de l’ordre de la centaine de microgramme par litre sur les deux sites cités.

Quant à la chlordécone trouvée à Sainte-Claire ou Viard, elle est issue d’une pollution antérieure des sols bien connue à part sur un des prélèvements de Sainte-Claire qui interroge. En somme, les sites de stockage clairement pointés du doigt sur l’Anse Maurice, l’Anse du Belley, le Cap de Capesterre de Marie-Galante, et l’Anse Colibri à la Désirade qui présente, elle, des pollutions également aux hydrocarbures et aux substances chimiques liées à l’industrie marine. Les algues qui sont stockées sont essentiellement celles draguées au cœur du port de l’île.

Un certain nombre de préconisations par le bureau
Compte tenu de ces résultats, les scientifiques préconisent d’abord de réguler les accès. Ce n’est pas le cas. Ces espaces constituent souvent des lieux d’abreuvages et une source de contamination certaine pour les visiteurs. Le clôturage est même recommandé pour les plus pollués comme du Belley, Anse Maurice, le Cap ou Anse Colibri.

Et une signalétique a minima pour les autres ou ceux à venir car certains pourraient être fermés notamment tous les sites de stockage qui sont à proximité d’habitations. Une hérésie, d’ailleurs, les nouveaux sites devront être choisis en fonction de leur non proximité donc avec les lieux d’habitation mais aussi avec les zones touristiques ou encore les zones protégées.

Il convient également de les aménager en y incluant des fossés pour canaliser les jus de sargasses hautement toxiques. Les sites de stockage qui présentent, par ailleurs, des enjeux capitaux pour la ressource en eau potable comme celui de Marie-Galante, doivent impérativement faire l’objet désormais d’un suivi de la qualité de l’eau. Enfin, les experts du bureau d’études préconisent également de sortir de la norme qui règlementent actuellement ces sites pour tendre vers une autre, nettement plus adaptée.

 

Source: Guadeloupe La 1re du 26/09/2022

Sargassum is worsening the conditions of the poorest people in Ghana

provided by Dr Victoria Dominguez Almela1 & Dr Philip-Neri Jayson-Quashigah2 and tells the story learned during the SARTRAC fieldtrip to the remote coastal areas of Sanzule, Beyin and Esiama, Ghana.

Sargassum, a type of brown seaweed, has been invading coastal areas across the Atlantic since 2011 and has become a major issue for fisheries, tourism and recreational industries. From Central America to West Africa, communities living along the coast are facing daily challenges due to the invasion of Sargassum.

Fishers from affected communities in Ghana (including Sanzule, Beyin and Esiama) are finding, for two to three months a year, that they are catching sargassum in their nets instead of fish (Picture 1).

Fishing is one of the main livelihood sources for most of the coastal communities in Ghana, so the whole coastal economy is affected by this seaweed influx.

Fishermen, who spend money on petrol for their boats, get insufficient fish from the sea to recover that money. The fish processors and sellers, predominantly women, cannot buy fish from the fishers, nor sell it on to the community as part of their livelihoods. Survival is under threat in those villages that rely on fisheries to provide their daily food (fish) and to generate their incomes (through fish sales, fish processing and the support industries).

Sargassum is affecting life in coastal Ghana in other ways too. Saturday is the day that communities typically spend time on the beach, relaxing, playing football, swimming, etc, but the presence of Sargassum on the beach hinders these recreational activities. The pungent scent released from the seaweed is affecting the people, with some reporting difficulties in breathing from allergic and asthmatic reactions. As the beaches are more frequently covered in seaweed, some users are starting to change the way they perceive the beach: from recreation hotspot to a toilet – which further discourages people from using the beach for recreation. Limited access to toilet facilities in some villages, is part of this problem.

Communities have tried to give visibility to the problem of seaweed influxes by reporting their plight to the District Assembly and council. In 2016 the government launched a programme to clear sargassum from the coast, but this has now stopped. Yet the problem continues. No long-term management has been put in place yet, and communities feel powerless to fight this hazard on their own.

Scientists point to an unusual weather event in 2010 as the starting point of the seaweed invasion, with ocean currents and winds determining the areas affected. In Ghana, coincidentally, sargassum started to beach just around the same time offshore oil drilling started off the western coast, which made the communities think that oil companies were responsible for the seaweed. This has brought a tension between local residents and the oil companies. Local residents welcome any research that helps them to better understand the drivers of sargassum and how to best deal with the consequences.

Through the SARTRAC project, partnerships have been developed among universities in the Caribbean, Ghana and the UK. These partnerships are strengthening capacity and research on sargassum monitoring, reporting, management, value assessment and re-use. We look forward to engaging local community members, including students and researchers, to find a lasting solution to sargassum, its scientific composition and possible uses.

1School of Geography and Environmental Science, University of Southampton, Southampton SO17 1BJ, UK

2Institute for Environment and Sanitation Studies, University of Ghana, Ghana

 

Source: SARTRAC 16/09/2022

Un mystère aux proportions océaniques : des algues sargasses forment désormais un pont végétal entre l’Amérique et l’Afrique

 

C’est la plus grande prolifération d’algues marines jamais enregistrée, s’étendant sur 8 850 kilomètres à travers l’océan Atlantique. Vingt millions de tonnes de Sargasses, soit plus que le poids de 200 porte-avions, envahissent la surface de la mer ; et cette masse ne cesse de croître depuis 2011. Cette prolifération jamais vue serait causée par les rejets de polluants de part et d’autre de l’Atlantique, par la déforestation et le réchauffement climatique.

À l’aide de données satellitaires de la NASA et d’échantillons recueillis sur le terrain, des chercheurs américains ont observé l’évolution de ce que l’on connaît depuis longtemps comme étant « la Grande ceinture de sargasses de l’Atlantique ». Mais ce qu’ils ont découvert, et qui fait l’objet d’un article dans la revue Science, dépasse toutes leurs prévisions. Cette ceinture prolifère a un point tel, qu’elle établit désormais une jonction entre le golfe du Mexique, les Antilles et l’embouchure de l’Amazone, à l’Ouest, et la côte Ouest de l’Afrique. Selon les chercheurs, le point de basculement se situe en 2011. Depuis cette date, l’expansion de la ceinture de Sargasses n’a cessé de croître et selon leurs prévisions, va continuer de plus belle.

Les chercheurs sont prudents sur les causes exactes de ce phénomène inédit. Toutefois, ils établissent un faisceau de présomptions pour
incriminer l’augmentation de la déforestation et de l’utilisation d’engrais au Brésil et dans toute l’Amazonie, à partir du début de la décennie. « Les
preuves de l’enrichissement en éléments nutritifs sont préliminaires et fondées sur des données de terrain limitées et d’autres données
environnementales, et nous avons besoin de plus de recherche pour confirmer cette hypothèse », déclare Chuanmin Hu, directeur de l’étude et
océanographe à l’Université de Floride du Sud.
L’autre cause vraisemblable pourrait être une élévation du niveau de la mer au large de l’Afrique de l’Ouest qui aurait soulevé des quantités de
nutriments des eaux profondes vers la surface.
Enfin, les scientifiques pensent que l’élévation de la température de l’eau de l’océan et des proportions de sa salinité ont joué un rôle considérable
dans la prolifération de ces algues.
La question qui se pose immédiatement est celle de savoir si cette prolifération est un danger pour l’océan. La réponse n’est pas tranchée. En effet,
les sargasses forment de vastes bancs d’algues brunes tissés en mailles serrées, sur une épaisseur qui peut atteindre un mètre ; elles fournissent des habitats à de nombreuses espèces marines comme les tortues, les crabes, certains poissons et oiseaux. Elles produisent de l’oxygène en abondance, ce qui permet à la vie marine de bien se développer.
En revanche, une trop grande prolifération de sargasses peut restreindre la circulation et la respiration de certaines espèces, notamment autour des régions côtières. De plus, quand les sargasses meurent, elles étouffent les coraux et certaines variétés de la flore marine.

Sargasses rejetées sur une plage du Mexique en juin 2019

L’inconvénient le plus visible se situe toutefois sur les plages de l’Atlantique, des Antilles, des Caraïbes ou d’Afrique touchées par cette prolifération d’algues. La Sargasse rejetée sur les côtes, quand elle entre en putréfaction, produit de l’ammoniac et de l’hydrogène sulfuré. Ces gaz dégagent non seulement une odeur désagréable d’œuf pourri, mais aussi peuvent être très toxiques, voire mortels, pour la santé humaine ou celle des animaux terrestres. Les conséquences économiques sont désastreuses pour les villes côtières touchées par cette marée brune : les touristes fuient et le sports sont paralysés, privant certaines îles et zones côtières de tout approvisionnement.
Les îles des Antilles françaises sont particulièrement touchées par cette invasion pestilentielle. La saison 2022 a vu des nappes continues de végétaux arriver le long des côtes. Une centaine de sites sont affectés dont une vingtaine de sites naturels où les algues étouffent progressivement la mangrove. L’odeur est insupportable et la santé des riverains est déjà atteinte par ces proliférations : céphalées, problèmes digestifs, cardiaques, risque de prééclampsies chez les femmes enceintes vivant près du littoral.

Les communes antillaises font de leur mieux pour effectuer le ramassage et le stockage des algues, mais la tâche est herculéenne et leurs moyens
sont limités. L’Etat, quant à lui apparaît peu visible. Plusieurs amendements ont été déposés au fil des mandatures au Parlement mais aucun n’est
parvenu à faire reconnaître les échouages de sargasses comme une catastrophe naturelle afin que les riverains puissent espérer une indemnisation. Certes, les plans Sargasse se succèdent mais les mesures administratives sont lentes à se mettre en place pour tenter de résoudre le problème. Pendant ce temps, l’urgence grandit mettant en danger quotidiennement la santé des habitants.

Source: UP’Magasine 31/08/2022

Republica Dominicana : Sargazo llega hasta las costas de Samaná afectando las aguas del mar

Una gran cantidad de sargazo está afectando la zona de la Talanquera del distrito municipal de las Galeras en la provincia de Samaná.

A través de un audiovisual se puede observar la gran cantidad de sargazo que arropa las aguas del mar, el cual llega hasta las costas de Samaná.

En los últimos tiempos el sargazo ha afectado la zona este del país, donde se ven impactadas las playas de Juan Dolio, Punta cana, Samaná, Hato Mayor, entre otros.

El pasado 20 de junio ser envió el primer contenedor lleno de sargazo a Finlandia como parte de la búsqueda de solución a las macroalgas que se mantienen afectando las playas del país.

Mientras que el Instituto Tecnológico de Santo Domingo (Intec) y la Asociación Nacional de Hoteles y Turismo de República Dominicana (Asonahores) firmaron un convenio de colaboración para realizar actividades de capacitación, de investigación y de identificación y promoción de soluciones a los problemas ocasionados por el sargazo.

Se recuerda que en el 2020 el presidente de la República, Luis Abinader, firmó dos acuerdos en torno a esta problemática, con lo que se comprometió a la intervención y rescate de 35 playas del país.

Ver la video aqui:   https://youtu.be/YpQyov5Z3bo  

Fuente : n.m.com.do

Mexico : Sargazo, amenaza para el turismo y la salud

Los trabajadores que retiran el sargazo de las playas, se exponen a una elevada cantidad de gas que se desprende al escarbarlo.

Se espera que el 2022 sea el año en que más sargazo se acumule en las playas mexicanas

El problema del sargazo que se acumula en algunas playas de la Riviera Maya, como Tulum, Xcalak y Playa del Carmen, no solo tiene que ver con el mal olor, es también una cuestión de salud por el riesgo que representa el retirar ‘montañas’ de algas, según científicos.

Cuando se descompone, el sargazo produce un ácido sulfhídrico, un gas que en cantidades pequeñas representa solo una molestia por su olor sulfúrico, parecido a un huevo podrido. Pero cuando se trata de enormes cantidades acumuladas en las playas, son muy peligrosas para los trabajadores que padecen de problemas respiratorios, pues las retiran con rastrillos bajo unos fuertes rayos del sol y sin tapabocas.

Este 2022, se encamina como el año en que más sargazo se habrá acumulado en las playas, superando el récord del 2018.

De acuerdo con la bióloga Rosa Rodríguez Martínez, los trabajadores se exponen a algo más que a un calor abrasador. “La cantidad de gases que se desprenden al escarbar el sargazo, en una ocasión llegó hasta 56 por millón. Es altísimo arriba de dos y es peligroso para la gente con problemas respiratorios”.

La mayoría de los trabajadores que retiran sargazo, no usa tapabocas ni cuenta con sensores de gases o servicios médicos; tratan de retirarlo de la playa lo más rápidamente posible, cuando todavía está fresco, de acuerdo con una publicación de sandiegouniontribune.com.

Un artículo publicado en Journal of Travel Medicine en el 2019 señalaba que “una exposición crónica a estos gases puede provocar síntomas conjuntivales y neurocognitivos, como pérdida de la memoria y problemas de equilibrio, además de síntomas no específicos como dolores de cabeza, náuseas y fatiga”.

Por su parte, el Departamento de Salud de Florida, en Estados Unidos, indicó que “el ácido sulfhídrico presente en sitios como las playas, donde grandes cantidades de aire pueden diluirlo, no debería afectar la salud”.

No obstante, el tema del sargazo representa molestias para los trabajadores que lo retiran, como para los turistas.

A menudo, en el sargazo hay hidrozoos, parientes de las aguavivas, que cuando se pasa mucho tiempo en contacto con las algas, se pueden sufrir muchas picaduras de hidrozoos, que son tóxicos.

Hoy en día, cuesta trabajo medir el impacto del sargazo en el turismo. La Riviera Maya sufrió una disminución de turistas a causa de la pandemia, sin embargo, la actividad turística no se paralizó porque México no impuso restricciones y los turistas estadounidenses siguieron llegando.

Entre enero y junio de este año, el turismo internacional superó los niveles previos a la pandemia, con 10.26 millones de visitantes, cifra 1.5% mayor que en la primera mitad del 2019. Pero el panorama sigue siendo complicado, ya que mientras siga llegando el sargazo a las costas mexicanas, el problema continuará.

Fuente/Source : realestatemarket.com.mx 01/09/2022

Mexico: On Mexico’s Caribbean coast, mountains of seaweed grow

Workers who were hired by residents remove sargassum seaweed from the Bay of Soliman, north of Tulum, Quintana Roo state, Mexico, Wednesday, Aug. 3, 2022. (AP Photo/Eduardo Verdugo)

TULUM, Mexico (AP) — Scraping the smelly sargassum seaweed off some beaches on Mexico’s resort-studded Caribbean coast has become not only a nightmare, but possibly a health threat, for the workers doing it — with the quantities washing ashore this year seemingly mountains not mounds.

Decomposing sargassum, which is actually algae, generates hydrogen sulfide gas. In small amounts in open areas, it’s not much more than an annoying odor: sulfurous, like rotting eggs.

Birds walk on sargassum seaweed floating on the Caribbean Sea in Tulum, Quintana Roo state, Mexico, Friday, Aug. 5, 2022. (AP Photo/Eduardo Verdugo)

But in the quantities seen in once-paradisical beach towns like Playa del Carmen, Tulum, and Xcalak, scientists say it can be dangerous to workers with respiratory problems as they rake up the seaweed maskless in the scorching heat. This year appears on track to be worse than even the peak sargassum year of 2018.

Ezequiel Martínez Lara is one of thousands of laborers who work six to eight hours per day heaving mounds of sargassum into wheelbarrows with pitchforks and then wheeling them off the beach to a growing pile on a neighboring street.

Martínez Lara used to earn as much as $50 per day guiding sports fishermen on catch-and-release outings, but now makes less than half that for collecting around 40 wheelbarrows of sargassum every day.

Workers who were hired by residents remove sargassum seaweed from the Bay of Soliman, north of Tulum, Quintana Roo state, Mexico, Wednesday, Aug. 3, 2022. (AP Photo/Eduardo Verdugo)

It is a Sisyphean task at a beach north of Tulum, where huge mats of seaweed float just offshore.

“If we clean it all off today, tomorrow more will have washed in,” said another worker, Austin Valle.

But workers like Martínez and Valle are exposing themselves to more than just the burning sun, says Rosa Rodríguez Martínez, a biologist in the beachside town of Puerto Morelos who studies reefs and coastal ecosystems for Mexico’s National Autonomous University.

“At the university we have started to measure the quantity of gases that sargassum produces when it is scraped up,” Rodríguez Martínez said. “At one spot (in a decomposed pile of seaweed) it reached 56 parts per million. That’s very high. Above two, that can be dangerous for people with respiratory problems.”

“I took off running” from the spot, she said.

Martínez Lara doesn’t have the luxury of avoiding the hydrogen sulfide gas. Like almost every other sargassum worker on the coast, he has no mask, gas sensor or medical care. He works at a day rate for the person who owns the house in front of the beach.

“When sargassum rots, it gives off a very strong odor like acid, and it is very bothersome when you breath it; it hurts a lot,” Martínez Lara said. He said he takes more simple precautions.

“We try to clean it off (the beach) as quickly as possible … to get it off when it is as fresh as possible,” he says.

A 2019 article in the Journal of Travel Medicine includes the disturbing warning, “More chronic exposure to these gasses can lead to conjunctival and neurocognitive symptoms such as memory loss and impaired balance, as well as non-specific symptoms such as headache, nausea and fatigue.”

The Florida Health Department, on the other hand, says “hydrogen sulfide levels in an area like the beach, where large amounts of air flow can dilute levels, is not expected to harm health.”

The sargassum problem isn’t as bad for tourists as for workers. But neither is it pleasant.

Ligia Collado-Vides, a marine botanist at Florida International University who specializes in studying macroalgae like sargassum, said, “If you’re swimming for a little bit, it shouldn’t be a danger at all,” but added that tiny jellyfish cousins known as hydrozoa often inhabit sargassum mats.

“If you’re going to be there for a long time playing in the sargassum, you can get like many, many, many stings from hydrozoans and those are toxic,” she noted, adding that long sleeves — something almost nobody wears at the beach — might help.

Sargassum seaweed colors the water brown and covers the beach in the Bay of Soliman, north of Tulum, Quintana Roo state, Mexico, where workers hired by local residents remove it by hand, Wednesday, Aug. 3, 2022. (AP Photo/Eduardo Verdugo)

Sarah Callaway, a tourist from Denver, Colorado, was pretty much confined to playing with her kids in the pool in front of their rented beach house.

“The property is beautiful, but we were automatically struck … by the smell,” Callaway said. “The smell is really pungent and very strong. And then, yeah, we were disappointed with how much seaweed sargasso there is here.”

“The kids have tried to get in the ocean, but then they get kind of overwhelmed by it. So we really haven’t gotten to do the beach part of it, which is why we came,” she said.

It will also impact locals who depend on the tourist trade. Hundreds of thousands of people migrated to the coast in recent years for better paying jobs, but some may now be considering leaving.

Valle, the seaweed cleaner, said one of his friends in Tulum has been thinking of giving up her snack stand business because sales have dipped so much.

It’s hard to measure the impact on tourism. The Caribbean coast suffered a drop in visits during the coronavirus pandemic, but because Mexico never declared travel restrictions, testing requirements or mandatory mask rules, Americans have continued to come.

Workers who were hired by residents remove sargassum seaweed from the Bay of Soliman, north of Tulum, Quintana Roo state, Mexico, Wednesday, Aug. 3, 2022. (AP Photo/Eduardo Verdugo)

International tourism to the country as a whole surpassed pre-pandemic levels in the first half of 2022, with 10.26 million visitors from January to June, 1.5% higher than the 10.11 million tourists who arrived in Mexico in the first half of 2019.

Mexico’s strongest showing was with U.S. tourists. The number of Americans arriving by air in the first six months of 2022 was 6.66 million; that is 19.1% higher than in the same period of 2019.

But that boom may be slowing. Grupo Financiero Base noted in a research report that international tourist arrivals in June 2022 were down 13.8% from levels in June 2019. It’s unclear what — sargassum, inflation, or the war in Ukraine — may have caused that dip.

And overall tourist spending remains below pre-pandemic levels.

The picture is mixed because some of the most-heavily developed resorts like Cancun have not suffered as much from sargassum as lower-key resorts further south, like Playa del Carmen and Tulum.

Ocean currents and islands like Isla Mujeres shield Cancun from much of the floating sargassum. Given the large number of big hotels in Cancun with huge cleaning staffs and money to deploy floating booms, what sargassum does arrive is cleaned up more quickly.

The jury is still out on the floating booms, meant to trap sargassum mats at sea before they reach the beach.

Some tourists like the area so much they’ll keep coming back.

“I will absolutely be back. We love it here,” said Jeff Chambers, a tourist from Palm Desert, California, who was strolling down the main seaside street in Tulum. “We like things a little slower.”

A bird floats amid sargassum seaweed in Tulum, Quintana Roo state, Mexico, Friday, Aug. 5, 2022. (AP Photo/Eduardo Verdugo)

Some locals like Victor Reyes, who works in real estate in Tulum, are more sanguine about the seaweed, noting that it’s not so bad in the winter months.

“In the winter it’s better. In November, when the tourists want to come, the sargassum is gone,” Reyes says.

As bad as sargassum is for people — and Collado-Vides stresses that much more study is needed — it’s far worse for seagrass, fish and other marine life suffocated by seaweed that drops to the bottom, decomposes and creates oxygen-depleted or anoxic layers similar to dead zones.

“Sargassum stays there and goes down into the water column so nobody sees it, but on the bottom it is creating anoxic conditions,” she said.

Recounting one recent monitoring expedition, Collado-Vides said: “It’s really terrible … the amount of vertebrates, the amount of crabs, the amount of fish dead in just a 1-square meter quadrant.”

 

Source: AP NEWS 30/08/2022

Florida USA : Invasion of the seaweed. South Florida’s beaches see record volume this summer

Beach goers walk among the sargassum along the beach at Collins Avenue and 27th Street in Miami Beach. The mats this week have been modest but MIami-Dade has seen record amounts this summer. PEDRO PORTAL

Every morning, before a storm of visitors rains down on Miami Beach, a hefty tractor rakes the shoreline, scooping up a brown stinky seaweed known as sargassum.

Normally, the process runs like clockwork for the Miami-Dade County Parks and Recreation Department. But in recent months, it’s become a more laborious effort as record amounts taint the county’s coastline.

With months left in the typical seaweed season, the county’s collected tonnage has already surpassed the last two years.

“This is probably the most we’ve seen since 2018,” said Tom Morgan, chief of operations for the county’s parks department. “We get patrons on the beach that stop us and flag us down and ask us what’s happening.”

Sargassum is not inherently hazardous. On the ocean’s surface, in fact, the drifting algae is a vital part of a larger ecosystem, providing essential habitat for invertebrates, fish, crabs and shrimp.

But, in excess volume, it can be a problem for human and marine life alike. Massive mats of the scratchy stuff can make swimming and strolling unpleasant for beach goers.

A tractor rakes up seaweed on Miami Beach on Thursday. The mats this week have been modest but MIami-Dade has seen record amounts this summer. Pedro Portal

And when too much sargassum is strung along the shore, it can create a barrier for freshly hatched sea turtles that scuttle from sand to sea. When too much floats atop the water for too long, it can block light from trickling below the ocean’s surface and suck up oxygen necessary for mangroves and marine life.

Then there is the smell. Fermenting in South Florida’s summer sun, the hydrogen sulfide produced by decomposing seaweed creates a stench likened to rotten eggs, an aroma that tends to turn off tourists.

It can even be a health problem. The National Institute for Occupational Safety and Health reports it can cause “irritation to the eyes and respiratory system.” In especially high concentrations, the gas can cause apnea, coma, convulsions, dizziness, headache, weakness, irritability, insomnia and an upset stomach. Studies also show a correlation between the seaweed’s growth and a bacteria that frequently closes beaches to swimmers.

The sargassum collection crew in the county’s parks and recreation department cleans all the beaches from Miami Beach to the Broward County line “three times a day, seven days a week.” Their beach “raker” logs documenting seaweed volume only date back to 2018, when the county first experienced a then-unprecedented outbreak of sargassum and began keeping tabs on the tonnage.

“Prior to 2018, we didn’t see large amounts of sargassum washing up on our shoreline,” Morgan said. “We’re learning to live it. And I think we’re managing it better than we have.”

The “raker” log data shows that the total amount of sargassum collected in the county from October 2019 to September 2020 totaled about 15,000 tons. That number grew to more than 21,000 tons the following year.

A thick mat of sargassum seaweed washed ashore Thursday on Miami Beach, part of a record volume seen so far this summer on South Florida beaches. Pedro Portal

This year, with August and September still unaccounted for, the logs show almost 25,000 tons of sargassum have been collected from beaches across the county.

Miami-Dade County is not the sole recipient of a sargassum outbreak. Broward and Palm Beach counties are also experiencing a record year for sargassum. So is the Caribbean.

Although there is not yet a definitive explanation for the surge in seaweed, scientists hypothesize that contributing factors include temperature rises associated with climate change and nutrient pollution in the Atlantic Ocean caused by deforestation and fertilizer runoff. Those scientists include Helena Solo-Gabriele, a professor of environmental and materials engineering at the University of Miami, and her doctoral student Afeefa Abdool-Ghany.

Solo-Gabriele and Abdool-Ghany were co-authors of the first scientific study to analyze the relationship between sargassum and enterococci, a bacteria that is an indicator of human or animal waste in water. Miami-Dade County beaches were the focus of their study.

“Bacteria levels of beaches in Miami-Dade County have been increasing steadily over the past decade,” Solo-Gabriele said. “What we found was an increase in bacteria at the beach was related to increases in the sargassum. One feeds the other.”

The massive daily mounds scraped from beaches have also created another problem. What to do with it.

In areas that see the most sargassum accumulation, like around beach jetties, Morgan said the county has a contracted vendor who composts it.

“And then once it’s composted,” he said, “it can be used in certain applications as commercial fertilizer.”

Abdool-Ghany is also studying how well the seaweed fares as fertilizer. She’s already tested out various blends, including a solely sargassum blend and one that incorporates yard waste like grass clippings. Both have been successful; she’s already grown radish plants with the composted material.

“We were worried the salt from the sargassum would not allow the plants to grow. Little did we know it was not an issue whatsoever,” Solo-Gabriele said. “So you can take sargassum and put it in a composter, leave it there and after three months, it’s a sandy organic material. You can take that material and it will grow some plants.”

 

A crew cleans the sargassum along the beach at Collins Avenue and 27th Street in Miami Beach on Thursday, Aug. 25, 2022. Pedro Portal

The Florida Department of Environmental Protection is still in the process of creating safety guidelines for composting sargassum since the seaweed naturally contains arsenic, which is highly toxic to humans. But researchers like Abdool-Ghany are already at the forefront of finding the best ways to use the organic material — especially since sargassum is expected to remain in surplus.

“I think what this tells us is that we need to pay particular attention to climate change and start really thinking about the potential impact of temperature rise and sea level rise,” Solo-Gabriele said. “I think we’re just starting to see the beginning of it.”

A crew cleans the sargassum along the beach at Collins Avenue and 27th Street in Miami Beach on Thursday, Aug. 25, 2022. Pedro Portal

Source: Miami Herald 26/08/2022

Sargassum, the brown tide that is invading the Caribbean

The phenomenon has broken records this year and has become one of the great environmental concerns of the coastal areas of the region

Tourists swim at Xcalacoco beach next to sargassum in Playa del Carmen, Quintana Roo.
GLADYS SERRANO

More than six centuries ago, the first European expeditions that crossed the Atlantic to reach the American continent sighted a phenomenon known as sargassum. While documenting it, some of those explorers feared that their ships would get stuck in that brown tide. Now, in the last decade, sargassum has been invading the Caribbean coasts, destroying its ecosystem and becoming a threat to the tourism sector.

It all began in the summer of 2011, when sargassum started to accumulate on the beaches of many destinations with crystal clear waters and white sands. Mexico was one of the first countries to report it, but this environmental problem, which is lethal to many species and also harmful to human health, concerns almost the entire Caribbean region. This year, the amount of sargassum has already reached historic figures in the Atlantic Ocean: in June, more than 24 million tons of the “brown tide” were recorded in the Caribbean coast, from Puerto Rico to Barbados, according to a report from the oceanography laboratory of the University of South Florida.

What is sargassum?

The term refers to an uncontrolled growth of the species Sargassum fluitans and S. natans, brownish seaweed that live in suspension in the seas and move along the Atlantic, dragged by ocean currents. Although most seaweed live in the depths, with their roots attached to the bottom of the sea, these two species can live at the surface because they have gas vesicles, an adaptative mechanism that improves photosynthesis and allows them to spend their lives floating, explains Rosa Rodríguez, a marine biologist at the Institute of Marine Sciences and Limnology of the National Autonomous University of Mexico (UNAM).

While the uncontrolled accumulation of these algae is toxic in coastal regions, causing the massive death of many marine species, in the open sea they play a very important role in maintaining ecological balance. The Sargasso Sea, in the North Atlantic Ocean, is an exceptional ecosystem that provides food and shelter for hundreds of species, some of them unique to this floating habitat. In addition to serving as a platform for the protection and sustenance of marine fauna, it is part of the migration path of species such as eels, turtles and whales.

Why did it become a problem?

When the unrestrained blankets of sargassum reach the coast, they prevent light from filtering to the seabed, which is essential for the biology of corals and types of algae that produce food through photosynthesis. This, in turn, affects the biodiversity of the system they support.

A woman walks on a bridge surrounded by sargassum in Puerto Morelos, near Cancun.
EDGARD GARRIDO (REUTERS)

One characteristic of sargassum is how quickly it can grow: in favorable conditions, it is able to double its biomass in less than 20 days. When the seaweed decompose on the shore, they consume large amounts of oxygen, causing anoxia and emitting toxic gases like hydrogen sulfide and methane, which are very dangerous for humans and can cause the mass death of many species.

The excess of nitrogen and phosphorus derived from the putrefaction process serves as fertilizer for them to grow more, generating leachates, sulfidic acid and arsenic, which are responsible for the fetid and rotten smell that has now become common in some Caribbean tourist destinations. Yet another problem, says the UNAM specialist, is the poor disposal of sargassum, which ends up becoming a pollutant.

Why is it produced, and where does it come from?

According to the strongest hypotheses, climate change is behind the spread and uncontrolled growth of sargassum. For years, various scientific studies have warned of how changes in the ocean currents due to the melting of the poles and glaciers, as well as the excessive ocean fertilization, are making this an increasingly common phenomenon.

The discharges and waste from industries and agriculture at the mouths of the great rivers of South America, such as the Amazon and the Orinoco, whose sediments and organic matter are pushed north by the currents, have caused seaweed to reproduce at a record speed, creating the Great Atlantic Sargassum Belt, a buildup of seaweed that is devastating the Caribbean coasts. “It is a clear example of how climate change affects us directly and indirectly,” points out the biologist.

Which regions are being affected?

Far from being an isolated phenomenon, the problem is impacting a large part of the Caribbean. The beaches of Belize, Honduras, Jamaica, Cuba, Mexico, the Dominican Republic and Barbados, or islands such as San Andres, Guadeloupe or Martinique, among others, are affected by the blankets of seaweed every year. “But large arrivals of sargassum have also reached the north coast of Brazil and even Florida,” says Rodríguez. This brown tide is not only impacting the Caribbean. The biologist explains, “it arrived in the Gulf of Mexico long before, but not in such high volumes.”

Sargassum at Yabucoa beach, in Puerto Rico, last august.
JONATHAN ALPEYRIE (BLOOMBERG)

The first report of the appearance of sargassum came from local fishermen and a newspaper in 2011, according to Chuanmin Hu, an oceanographer with the University of South Florida team, which began tracking its growth in the Gulf of Mexico in 2006.

Is sargassum here to stay?

Hu is the author of a study that in 2019 warned that a change in the ocean currents was increasing the possibility that recurrent sargassum blooms in the tropical Atlantic and the Caribbean Sea would become the new norm. According to Hu, the data suggests that the amount of sargassum that reaches the coasts is growing steadily. According to Rodríguez, even though there is not enough information on the biomass that is reaching the different regions of the Caribbean, which fluctuates every year, “everything suggests that not only the problem will remain, but it will take a turn for the worse.”

Can it be controlled?

Since the problem was pointed out by environmentalists and hotel owners, governments have sought ways to clean their affected beaches in order to recover tourism. Nonetheless, Rodríguez explains that the resources invested so far have not been efficient. “Only a small area of the coast is being looked after, and ecosystems that are also affected by sargassum, like the mangroves and the jungle, are not being cared for,” she points out.

What’s more, the strategy of directly removing the buildup of seaweed from the coasts has a very negative impact. “A little sargassum helps prevent beach erosion, but when it’s a lot it has the opposite effect. And with the heavy machinery that is used to extract the seaweed, they remove a lot of sand,” says the UNAM expert. Another problem that stems from the removal of sargassum is how poorly they dispose of it. “Sargassum has a lot of arsenic, but also cadmium, lead and other heavy metals, as well as dangerous bacteria that pollute the environment,” she warns.

What to do with sargassum?

The arrival of sargassum in the Caribbean can be an opportunity for various industries, and in recent years different initiatives have promoted its use as a raw material.

The different properties of sargassum can be used by sectors ranging from construction to pharmaceuticals or the energy industry. Research centers and universities, for example, are using it as a source of biofuel, thanks to its composition of lignin, cellulose and hemicellulose; sodium alginate, a polysaccharide that can also be found in sargassum and that acts as a thickener, is used in the textile industry and for haute cuisine.

With the aim of promoting the principles of the circular economy, which uses everything while creating added value, some companies are taking advantage of the impurities left over from the alginate extraction process, such as fucoidans. These biopolymers, whose antitumor and immunomodulatory properties are currently being researched, could even be used as cancer therapies, according to some studies.

Source/Fuente: El Pais 18 august 2022