“…Recent research has focused on the introduction to existing coastal infrastructures of artificial, water-filled features to enhance the ecological well-being of these structures. A common element of these features, regardless of whether they are "additive" (as in the case of bolt-on rock pools (Morris et al, 2017;Naylor et al, , 2018Strain et al, 2017;Hall et al, 2019;Figures 1A,B), or "textured concrete" or "textured surface" tiles (Perkol-Finkel and Sella, 2015;MacArthur et al, 2018; Figure 1C) on sea defences) or "subtractive" (as in the case of "drill-cored rock pools" in intertidal breakwaters (Browne and Chapman, 2014;Firth et al, 2014a,b;Evans et al, 2016;Hall et al, 2018;Waltham and Sheaves, 2020; Figure 1D), is that they serve to increase the topographic complexity and the surface roughness of the structures to which they are added.…”