A Paleobiological Perspective on Sabkhas

Abstract

At first glance, coastal sabkhas appear to be singularly esoteric environments, hardly meriting the painstaking geochemical and ecological study they have received in recent years. Sabkhas are forbiddingly arid, extremely limited in geographical extent, and notable biologically largely for the absence of most organisms that figure prominently in twentieth centuary bestiaries. The microbial mat communities characteristic of sabkhas are easily disrupted by minor environmental fluctuations, leaving the casual observer with the impression that these ecosystems are fragile and geologically evanescent. It is in fact the geological record that gives lie to this impression, documenting the persistence of arid coastal environments and their biotas in both ecological and evolutionary time and demonstrating the critical importance of an understanding of modern sabkha communities for the interpretation of the Earth’s earliest records of life.