Production of methane and gaseous compounds by surface microbial activity in a small pockmark field, Dunmanus Bay, Ireland

Marine pockmarks are globally widespread seabed depressions, conventionally thought to be formed by the accumulation and expulsion of microbial and thermogenic gas. However, other putative fluids and processes have been implicated in pockmark formation and gas escape to the atmosphere may be underestimated. Given the complex spectrum of aquatic settings, morphologies and sizes, there may also exist a spectrum of physical, chemical and biological processes that form pockmarks. Pockmarks in shallow coastal waters are now understood to be widespread, but the influence of physical dynamics (e.g. tides, storms, etc.), terrestrial processes and anthropogenic activities add considerable spatiotemporal complexity and uncertainty to our understanding of these features. Here, we revisit a field of small (ca. 2 m diameter), shallow