Cenotes – Lakes of the Yucatan Peninsula (Mexico)

Abstract Cenote lakes are natural sinkholes or depressions resulting from the collapse of limestone bedrock exposing the groundwater underneath. Thousands of such lakes are particularly encountered on the Yucatan Peninsula (Mexico). These lakes were of great significance for the Maya culture as important religious places and primary source of drinking water. They permitted the survival of Mayan communities through dry periods known as “Maya drought”. Most of the cenote lakes are large open water pools measuring tens of meters in diameter. The majority of cenotes are smaller sheliered sites. Their waiers are usually very clear and oligotrophic, originating from rain waier filtering slowly through the ground. The auihors visited and coliected zooplankion samples from eight cenotes in November 2013, namely: Ik-Kil, Samula, Zaci, X-Kekn, Actum Ha, Cristal, Sian Ka’an, and Chan Chemuxil (transect Merida-Tulum- Cancun). The analysed lakes differ considerably in morphological terms, varying from very deep to shallow. Some of them are under human impact (tourists). The water samples were anaiysed for zooplankton content, but the phytoplankton frequently occurring was also taken into account. The obtained results are largely varied, indicated big ecological verity among cenotes which depended on lake age, localization and morphometry. As showed our study Cladocera zooplankion was very rare and only present at several sites. Beiween the fauna community Copepoda and Ostracoda species were the most abundant. Phytoplankton were present in all studied lakes and it sees that played the central role in those ecosystems.