"Anchialine deep subterranean waters on Cozumel Island" by Luis Mejia-Ortiz (Pres 14: 5ISAE)
This presentation was a part of the 5th International Symposium on Anchialine Ecosystems (5ISAE), held in Kailua-Kona November 3-5, 2022.
Presentation 14: "Anchialine deep subterranean waters on Cozumel Island: connections between surface variation and faunal distribution"
Session 3: Mexico & Caribbean - Biological & Earth Sciences
Presentation Authors: Luis M. Mejia-Ortiz (1), D. Montserrat Arriaga-Velez (2), Tanja Pipan (3), David C. Culver (4), German Yáñez (5)
Affiliations: (1) University Autonomous of Quintana Roo State, Cozumel, Mexico; (2) Facultad de Ciencias, UNAM, CdMx Mexico; (3) ZRC SAZU Karst Research Institute, Slovenia; (4) Department of Environmental Science, American University, Washington DC, USA; (5) Speleological Circle of Mayab, Cozumel, Mexico
Presentation Abstract: Subterranean environments have been reported as semi-isolated systems, but always with some external influences through physical and biological factors. In anchialine caves, hydrological regimes, especially rainfall, influence temperature and organic matter contents, with the existence of different water layers throughout the year reaching deeper regions in these systems. In this work we describe how in an anchialine deep ecosystem, Cenote Chempita, for which meteorological conditions and water physical-chemical variables only have a strong relationship in the first layer of freshwater, and apparently without changes in the deeper zones. Organic matter sources in the tropical forest influence the brackish layer below the freshwater layer. Changes in the community composition of stygobionts in the deeper zones depend on available dissolved oxygen. Cenote Chempita has three permanent layers a) freshwater, b) brackish water, and c) marine water: due their depth the thicknesses of these layers are permanent year-round. Also, analysis of monitoring data of two main variables, oxygen and temperature, was carried out each hour during a year to identify and understand the hypoxic conditions in this anchialine cave with dissolved sulfur in the water (a product of organic matter decomposition). In the marine layer, the diversity of crustaceans is richest, and community dynamics during each month show that shrimp are present year-round but Remipedia and isopods have a special seasonal relationship with colder months. In the case of Remipedia, we monitored presence-absence during some months (nortes season) and found that oxygen has a major influence on the presence of this taxon in the marine layer. Although, these environmental changes are minimal, they are influenced by outside conditions: in the first instance depth plays an important role in causing changes to be small and leading to strong stability among layers.