The blurred line between photic and aphotic environments: a large Mexican cave with almost no dark zone
- Muevelo Rico has almost no dark zone, throwing into relief what constitutes a cave
- Light is present in most of the cave, as are reduced daily temperature and humidity cycles
- Troglomorphic species and their potential predators occur throughout the cave
- The presence of troglomorphic species is best explained by the presence of organic matter in photic zones
Sistema Muévelo Rico is a 1.2 km long cave in Quintana Roo, less than 2 km from the Caribbean Sea. We measured illuminance to a level of 0.1 lux, organic matter (weight loss on ignition), temperature, and relative humidity. The last two were measured at hourly intervals for nearly one year. Approximately one-third of the cave has illuminance values greater than 0.01 lux, and most of the rest of the cave has light as well. Temperature and relative humidity were relatively constant, but they showed a daily cycle at all stations, albeit with different strengths. Organic matter averaged 8%, intermediate in value between surface and aphotic zones. Both eyeless species and eyed predators occurred throughout the cave. Their occurrence can best be explained by their foraging for organic matter and incurring an increased risk of predation.
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Mejía-Ortíz, Luis M.; Tanja Pipan; David C. Culver; and Peter Sprouse.
The blurred line between photic and aphotic environments: a large Mexican cave with almost no dark zone.
International Journal of Speleology,
Available at: https://digitalcommons.usf.edu/ijs/vol47/iss1/6
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