“…This is because microbial mats are subject to numerous biological and ecological pressures that work to inhibit their growth, including grazing and bioturbation from metazoans at the sediment surface and within the upper sediment column (Javor & Castenholz, 1984; Fenchel, 1998). These pressures on microbial mat formation can be suppressed, however, if environmental stress is sufficient to inhibit metazoan activity (Javor & Castenholz, 1984; Schubert & Bottjer, 1992; Mata & Bottjer, 2009a,b). For this reason it is common to find microbial mats in environments that are harsh to metazoans, but for which conditions are tolerable, if not hospitable, to abundant microbial life.…”