Laguna Bacalar: Research and Conservation in Mexico’s “World-Class Lake”
Giant Holocene microbialites, dreissenid mussels, and potential anthropogenic impacts
Laguna Bacalar in southern Quintana Roo, Mx, is one of the most visually stunning lakes on the planet. It’s white marl substrate and crystal-clear turquoise waters have earned in the nickname “The Lagoon of Seven Colors”, and it harbors several marine relic species including tarpon, bonefish, skate, and dwarf mangrove. It’s also home to the largest living microbialite (stromatolitic and thrombolitic) formations on Earth, representative of our planet’s most ancient lifeforms, existing in only a handful of locations worldwide. The lake’s beauty translates to a novel ecology and biogeochemistry, but also to a huge potential for commercial development. With almost no baseline data related to this system, our group from the University of Wisconsin-Milwaukee began to study its ecology, limnology, and biogeochemistry in 2011 (in conjunction with groups/individuals from Bacalar, Chetumal, and Mexico City).
My recent (2019) Presentation on Laguna Bacalar Research and Conservation
Low chlorophyll concentrations (2016) demonstrate Laguna Bacalar’s continued highly oligotrophic state
My role as an undergraduate and M.S. student largely involved documenting densities of a dreissenid mussel (Mytilopses saleii) on microbialite surfaces. Mussel populations currently appear to be held in check by low phytoplankton abundances in Laguna Bacalar’s oligotrophic waters, and the species may even entertain a symbiotic relationship with the microbialites themselves. As tourism advances south through the Riviera Maya however, human population growth could lead to nutrient influxes and subsequent cultural eutrophication—as it has in communities to the north (e.g., Cancun’s coastal lagoons)—leading not only to the loss of the lake’s seven colors, but also the rare microbialites, unable to photosynthesize if blanketed with an exploding mussel population.
Mytilopses sallei densities on microbialite surfaces, relatively unchanging from 2012-2016.
As of 2016, phytoplankton concentrations remained very low, indicating that Laguna Bacalar had likely not yet reached a “tipping point” in terms of runaway land-based nutrient influx. Mussel population data remained relatively constant from 2012-2016. That said, anthropogenic influence has not been completely nill—E.coli and fecal coliform bacterial assays resulted in several sites adjacent to the city of Bacalar harboring concentrations greatly exceeding U.S. E.P.A. water quality standards. The combination of the region’s porous karst topography and inadequate wastewater treatment has and will continue to become a growing threat in the face of an increasing human population on Laguna Bacalar’s shores.
Over the past few years, the scientific and local communities have made major strides in terms of the study and protection of Laguna Bacalar and it’s valuable natural resources. Two International Stromatolite Symposia in Bacalar brought scientists from several countries and municipal government officials together in 2011 and 2012, a number of scientific datasets have begun to amass, eco-tourism and community education in Bacalar is on a sharp rise (thanks in large part to local scientist/teacher Martin Maas), a number of graduate students from UW-Milwaukee presented Laguna Bacalar research to wider freshwater audiences at the 2016 and 2017 International Association for Great Lakes Research conferences, and the planning phase for a permanent research station in Bacalar officially began in late 2015.
Find out more about past Laguna Bacalar work at lagunabacalar.org.
This work was funded by the PADI Foundation and various other sources stemming from the University of Wisconsin-Milwaukee School of Freshwater Sciences and partners at ECOSUR Chetumal and the Universidad Autonoma de Mexico (UNAM).