Worldviews Sharon Reedyk & Robert Morgan

elcome to “Worldviews.” Cenotes of the Yucatán Peninsula, México This column will highlight the international character Roger Medina-González and Mark Brenner of the North American Lake WManagement Society by featuring the Roger Medina-González hole with water. There are an estimated activities of a NALMS member in an (Universidad Autónoma de Yucatán – 3,000 cenotes on the Yucatán Peninsula. international setting. We hope the column México) and NALMS member Mark Limnological characteristics of the will help build awareness of NALMS Brenner (University of Florida – USA) majority remain unknown. Few have been and encourage participation in NALMS have collaborated on limnological and studied systematically. world-wide. paleolimnological study of cenotes in Cenotes vary in size and shape. NALMS has been an international Mexico’s Yucatán Peninsula since the Some are large and cylindrical and society since its inception. As of May mid-1990s. Cenotes are water-filled completely open like the famous Sacred 2010, the society had 940 members solution features, which lie in the Cenote at the Maya site of Chichén from 15 different nations, including (in region’s karst terrain. The name derives Itzá (Figure 1). Others have only small no particular order): Australia, Canada, from the Maya word d’zonot meaning a openings at the rock surface with little Mexico, Austria, Denmark, India, Japan, Korea, New Zealand, Poland, China, South Africa, Spain, and the United States. Almost 8 percent of NALMS members come from Canada and 2.5 percent from other parts of the world. Of the 29 NALMS Symposia held, five were in Canada. NALMS members work on projects throughout the world. This column is a call to all those members to help throw a spot light on some of activities that take place internationally. Our first column highlights the work of member Mark Brenner and his colleague Roger Medina, who are conducting research in the Mexico’s Yucatan Peninsula.

Figure 1. The Sacred Cenote at the Maya archaeological site of Chichén Itzá. At this inland site, the water surface lies about 20 m below the land surface. The cenote long fascinated archaeologists, and dredging and diving operations in the 20th century yielded numerous artifacts, including human remains, ceramic vessels, and trade items from afar (e.g., obsidian and jade). This cenote was probably used principally for ceremonial purposes, and another more accessible cenote at the site was likely the drinking water source.

54 Fall 2010 / LAKELINE or no light penetration. Most display underwater cave development. The water that fills these solution basins represents the local aquifer. Near the north coast of the Yucatán Peninsula the water surface lies just below the land surface (Figure 2). Moving inland, the water Sharon Reedyk & lies considerably below the rock surface (Figure 1). Cenotes near the coast may Robert Morgan have fairly saline waters, while those of the interior are often fresher. Many cenotes first filled with water about 8,000-10,000 years ago. Since then, cenotes have played an important role in the environmental and human history of the region. Beginning about 3,000 years ago, the Maya used cenotes as sources of potable water. During the dry season from January to May, these water-filled sinkholes, along with local caves and constructed cisterns, provided the only reliable sources of water. Many high civilizations arose near major river systems. There are no rivers in the endorheic northern Yucatán. The Maya had cenotes. Most archaeological sites possess at least one cenote. Figure 2. Cenote Xlakah at the Maya archaeological site of Dzibilchaltun, only ~20 km from the Today, cenotes are recognized for the north coast of the Yucatán Peninsula. Note how close the water table is to the land surface. The role they play in supporting biological and cenote provides a cool break after a tour of the site. It is populated by a number of fish species cultural diversity. They provide habitat for (cichlids, livebearers, characins, and catfish), apple snails, and a host of aquatic plants. The pads many species of aquatic plants, algae, fish, of the water lily Nymphaea ampla can be seen. This was the primary water source for the human insects, crustaceans, mollusks, rotifers, inhabitants of this large center. cladocera, and protozoa, many endemic to the region and most poorly studied. They are also important water holes for resident and migratory animals. Some cenotes still serve as water sources and even sacred sites for the modern Maya people of Yucatán. There has been renewed interest in cenotes. In addition to serving as sources of water for drinking and bathing, cenotes are being exploited as tourist destinations (Figure 3). Along the Caribbean coast (“Maya Riviera”), cenotes have been developed exclusively for tourism. Stairs cut into the limestone walls provide access to the clear waters below. Unfortunately, many are being substantially modified before basic physico-chemical and biological information has been acquired. Other human activities affecting cenotes include fertilizer and pesticide runoff, swine and poultry operations, slash- and-burn agriculture, roads, and water withdrawal (Figure 4). Some are even used for solid waste disposal. Figure 3. Gran Cenote near the Caribbean coast of the Yucatán Peninsula. The cenote has been In recognition of the threats to the developed for tourism by virtue of its crystal clear waters.

Fall 2010 / LAKELINE 55 the University of Florida, where he is also director of the Land Use and Environmental Change Institute (LUECI). He teaches courses in limnology, paleolimnology, Florida lake management, and tropical field ecology, the latter in Yucatán, México. He has done fieldwork in México, Guatemala, Panama, Venezuela, Bolivia, the Galapagos Islands, Haiti, Dominican Republic, China, Cambodia, and Florida. You can reach Mark at: [email protected].

Sharon Reedyk has worked on projects that assessed the feasibility of various lake restoration technologies and the impacts of landscape disturbance on water resources. She currently works as a water quality specialist for Agriculture Canada where she assists the agriculture sector address impacts of agriculture on water quality. She has served several terms as a director of the Alberta Lake Management Society and more recently, was the program co-chair for the 2008 NALMS conference. You can contact Figure 4. Cenote Chen Ha near the town of Dzityá, just north of Mérida. This cenote is badly Sharon at: [email protected]. polluted by runoff from a nearby pig farm. The area around the cenote has also become a place for dumping solid waste. Bob Morgan, PhD, PE Is the manager of environmental quality Yucatán’s cenotes and the host of faculty member in the for Beaver Water District environmental services they provide, Ecology Department of a public water provider researchers at Universidad Autónoma the Facultad de Medicina in Lowell Arkansas. de Yucatán (UADY) are undertaking an Veterinaria y Zootecnia He is responsible interdisciplinary program to assemble (Veterinary Medicine and for protection of the what little data do exist on these Animal Science) at the District’s source water, unique water bodies, and to collect new Universidad Autónoma de 31,000-acre Beaver Lake. x information as well. The team consists Yucatán, Mérida, Yucatán, of natural and social scientists, and their México. He teaches students. The objectives of the project are: classes in limnology, aquatic ecology and (1) gather fundamental data on cenotes, socioeconomic and political importance of (2) raise public awareness concerning environmental problems. He coordinates the importance of cenotes, and (3) the Tropical Field Ecology class for UF formulate management plans to protect students in Yucatán. You can reach Roger at: these valuable water bodies. Though [email protected]. cenotes have served the needs of people for millennia, they still remain relatively Dr. Mark Brenner poorly studied. The efforts of the UADY is a limnologist/ project will soon provide a better paleolimnologist with understanding of these unique systems. special interests in tropical and subtropical lakes and watersheds. Chemist-biologist Roger Medina-González He is a professor in is a limnologist interested in the karstic the department of aquatic ecosystems of Yucatán. He is a geological sciences at

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