Sedimentary and Biological Patterns on Mudflats

Abstract

Apparently featureless ‘flat’ mudflats actually present striking biological patterning beneath the sediment surface, and even slight physical patterning by sediment ripple marks also leads to biological patterning of the surficial biofilm. The more topographically-complex hummock-forming mudflats are characterized by even more striking physical and biological patterning. In this chapter we first consider how the sediment-microbe association resists wave- and current-induced erosion, creating within-sediment structure (microbially-induced sedimentary structures, MISS). These structures may eventually succumb to high-energy erosion, creating superficial irregularity. We then describe how microbial and physical processes conjugate to form the spatially-complex, transitory hummock patterns. Finally, we summarize the biological patterning which emerges from the sedimentary structure and pattern on both flat and hummock mudflats.