The picturesque Montebello Lagoons in southeastern Chiapas, once renowned for their stunningly intense blue colors, have lately exhibited an unsettling transformation. The waters, now taken over by a greenish hue, reflect a story of environmental neglect that experts are finding hard to ignore.
Javier Alcocer Durand, a distinguished academic from the Faculty of Higher Studies (FES) Iztacala of UNAM, highlighted that this color shift is indicative of highly eutrophic waters. Delving deeper into the cause, Durand points to a disturbing trend spanning 80 years. The region has seen unchecked fertilizer use, aggressive logging, rapid urban expansion, and consistent release of sewage into its water systems.
The Montebello Lagoons hold a special place not just for their captivating beauty, but for their ecological significance. Surrounded by dense forests, these lagoons have historically attracted numerous tourists. Recognizing their ecological and aesthetic value, they were designated as a Natural Protected Area and a RAMSAR site – a testament to their global importance as a wetland under a UNESCO intergovernmental environmental treaty. They are also recognized as a Priority Hydrological Region by the National Commission for the Knowledge and Use of Biodiversity. But despite these titles, until 2015, there was scant information on the exact number of lagoons. Current studies peg the number at 139 within the national borders, with a similar cluster located in neighboring Guatemala.
The issue at hand isn’t merely aesthetic. The lagoons’ transformation from blue to green is a result of eutrophication—a process spurred by the influx of organic matter from sewage, run-off agricultural fertilizers, and sediments from cleared forest soils. This influx boosts the growth of phytoplankton, giving the waters their green tint.
Durand, together with his team of specialists from various institutes, has been actively monitoring the lagoons. Residents raised alarms upon witnessing the water’s changing hue, the appearance of surface cream, an unpleasant rotten egg smell, and increased fish mortality.
The geology of the area adds another layer of complexity. Composed primarily of limestone rock similar to the caverns and cenotes of the Yucatán Peninsula, the region has a unique geological makeup with faults and fractures that contribute to the creation of these aquatic bodies.
Worryingly, while some lagoons still retain their intense blue allure, they show traces of microorganisms typical of impacted sites. This suggests that eutrophication may soon dominate even these pristine lagoons.
Moreover, every lagoon in the region, though proximate, has its distinct biodiversity. This means that the degradation of each lagoon leads to a unique loss in regional biological richness. Durand stresses the urgency of this realization, signaling a pressing need for intervention.
Tourism, a vital economic activity for the local communities, is taking a hit. Many tourists, once attracted to the front lagoons, now bypass the deteriorated waters in favor of inland ones that remain untainted. This shift is causing rifts among local communities over unevenly distributed economic gains from tourism.
Beyond aesthetics and economics, there's a pressing health concern. Water from the affected lagoons, which was once potable, now poses a danger. Its usage for irrigation also comes with risks, as certain phytoplankton present produce toxins lethal to livestock.
To combat this crisis, Durand advocates for immediate pollution control measures, targeted environmental education programs, comprehensive training for local farmers, ranchers, and tourism stakeholders, and rigorous limnological monitoring. Such steps will pave the way for informed public policies, aimed at pollution control and eventual restoration of these precious lagoons.
For those interested in a deeper dive, Durand, along with colleagues Óscar Escolero and Fernando Álvarez, have penned a book titled “Las Lagunas de Montebello”: Joyas de la naturaleza amenazadas. Published under the UNAM editorial banner, the book can be accessed here.
In essence, the Montebello Lagoons' plight serves as a potent reminder: our natural wonders, no matter how revered, are not impervious to human impact. Proactive measures are crucial to ensure their legacy remains untarnished for future generations.