Bioirrigation in Marine Sediments

Bioirrigation refers to the enhanced transport of solutes across the sediment-water interface induced by the activities of bottom-dwelling organisms. This chapter provides an overview of what bioirrigation is, how it is induced, and how it affects processes in marine sediments. After discussing some well documented effects of bioirrigation such as the enhanced cycling of organic matter, nutrients, metals and pollutants, this article also touches upon phenomena that were uncovered more recently and deserve further attention, including rapid redox oscillations, bioadvection, and biohydraulic sediment cracking. Last but not least, some of the key methods used to study bioirrigation are presented, with special emphasis on imaging techniques that allow measurements with high spatial and temporal resolution. The chapter includes a number of graphics and videos that illustrate the highly dynamic and heterogeneous nature of bioirrigated sediments.