chapter  13
28 Pages

1Chapter 3 Subtropical Karstic Coastal Lagoon Assessment, Southeast Mexico: The Yucatan Peninsula Case

The Yucatan Peninsula of Mexico is characterized by numerous coastal lagoons, which are important both ecologically and economically. Wastewater discharge, groundwater pumping, and land use changes are modifying both the structure and function of these lagoons. Here, we assess the condition of 10 such lagoons, 5 on the Gulf of Mexico coast and 5 on the Caribbean coast of the peninsula, via multiple measures, including water quality variables, submerged aquatic vegetation, harmful phytoplankton species richness, and degree of eutrophication. Lagoons varied substantially

Abstract ..........................................................................................................................................307 13.1 Introduction ..........................................................................................................................308 13.2 Putting Yucatan Coastal Lagoons in Context .......................................................................309 13.3 Research and Monitoring Experience .................................................................................. 311 13.4 Characterization and Status of Yucatan Coastal Lagoons ................................................... 312

13.4.1 Celestún .................................................................................................................. 314 13.4.2 Chelem .................................................................................................................... 315 13.4.3 Dzilam .................................................................................................................... 317 13.4.4 Rio Lagartos ........................................................................................................... 318 13.4.5 Holbox .................................................................................................................... 320 13.4.6 Chacmochuk ........................................................................................................... 321 13.4.7 Nichupte ................................................................................................................. 324 13.4.8 Bojorquez ............................................................................................................... 325 13.4.9 Ascención Bay ........................................................................................................ 325 13.4.10 Chetumal ................................................................................................................ 326

13.5 What Have We Learned about This Karstic Ecosystem? ..................................................... 326 13.5.1 Water Quality Characteristics ................................................................................ 326 13.5.2 Phytoplankton ........................................................................................................ 328 13.5.3 Submerged Aquatic Vegetation (SAV) ................................................................... 328

13.6 Conclusions ........................................................................................................................... 329 Acknowledgments .......................................................................................................................... 329 References ...................................................................................................................................... 330

in terms of water quality, with much of this variation resulting from seasonal changes in lagoon salinity, which ranged from <10 to >40. Lagoon water quality generally suggested a low level of anthropogenic impact; however, two lagoons (Chelem on the Gulf side, and Bojorquez on the Caribbean side) showed signs of anthropogenic eutrophication, including high harmful phytoplankton species abundance and changes in seagrass cover. Additionally, lagoons on the Caribbean side of the peninsula differed considerably from those on the Gulf side. These results provide a baseline assessment of water quality in the Yucatan Peninsula’s coastal lagoons and underscore the importance of accounting for natural geographic variation in water quality when comparing different lagoons and characterizing current and future human impacts on them.