Community Structure and Foodweb Dynamics in an Anchialine Cave in the Yucatan Peninsula

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

It was long thought that dark, oxygen-poor habitats, such as much of the deep sea, were largely devoid of life and housed low density, yet diverse assemblages of endemic fauna. The discovery of hydrothermal vents in the 1970s and subsequent realization that non-light based energy sources fuel a variety of marine foodwebs via chemosynthesis in extreme environments have since revolutionized ecological thinking about such ecosystems. They are now known to be highly productive, exhibiting greater macrofaunal biomass, yet lower organismal diversity, than neighboring areas devoid of chemosynthetic influx. Pakes? research provides preliminary evidence that such a pattern may exist in another extreme ecosystem- underwater anchialine caves, in which a discrete marine layer rests beneath one or more isolated layers of brackish or freshwater. Most anchialine caves contain low densities of invertebrates, yet some have inexplicably large biomasses of shrimp and members of the Remipedia, a rare crustacean class discovered in 1981 and found only in subtropical anchialine caves. It is the aim of Pakes? dissertation to integrate studies of geochemistry, microbiology, invertebrate food web dynamics, and behavior to better understand whether chemosynthesis correlates with macrofaunal density and diversity as well as remipede feeding behaviors in these extreme ecosystems.