Distribution Patterns of Recent Microbial Endoliths in the Intertidal and Supratidal Zones, Bermuda
E.J. Hoffman, 1985. "Distribution Patterns of Recent Microbial Endoliths in the Intertidal and Supratidal Zones, Bermuda", Biogenic Structures: Their Use in Interpreting Depositional Environments, H. Allen Curran
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Previous work indicates that microbial endoliths exhibit distinct habitat preferences within the intertidal and supratidal zones of Bermuda. An analysis of species diversity and abundance for eight physically varying sites shows several trends which are typical for Bermuda. From the lower intertidal zone through the upper supratidal zone, there is a gradual reduction in the number of endolithic species and a change in the dominance of a given species. The intertidal and supratidal zones can be divided into four distinct, well-defined subzones on the basis of co-occurring assemblages of endoliths. These foursubzones can be correlated with visible changes in rock surface relief and color, tidal range, and invertebrate and macro-algal associations.
Most of the endolithic species, as well as their characteristic distributional patterns in Bermuda, are essentially the same as those found along Mediterranean coasts. Preliminary work in Florida and Jamaica suggests that these patterns may be typical for the Caribbean area.
Since a given assemblage of endolithic organisms occupies a certain position with respect to mean sea level, it can be used as an indicator of tidal range of intertidal and supratidal conditions. Thus, if preserved and recognized in the rock record, the endolithic assemblages described in this study could be used to identify and interpret ancient carbonate intertidal and supratidal sequences.
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Organisms of one sort or another today inhabit virtually every sediment environment on Earth, and the rock record tells us that this has been the case through the greater part of our planet’s history. Furthermore, organisms leave their mark in most sedimentary settings, either directly in the form of body fossils or indirectly as biogenic structures. In addition to their often profound modifying effects on substrates, ancient biogenic structures preserve a record of organism behavioral activity in response to substrate and other paleoenvironmental controls. Thus, biogenic structures can be highly useful as facies indicators and can provide valuable clues to the interpretation of paleodepositional environments. The purpose of this volume is to present a broad spectrum of case-book examples of the use of biogenic structures in the interpretation of depositional environments.