“…Facilitation of feeding density-dependent increase in rich organic material at feeding depth in sediment orbiniid, maldanid, and arenicolid polychaetes Rice (1986), Levin et al (1997) Boon and Havercamp (1979), Huettel et al (1996) Substrate stabilization refugia from disturbance angiosperm root structures, patches of large tubes, emergent bivalves; bacterial mats and diatom mats Woodin (1978), Irlandi (1997), Micheli (1997) Reise (2002), Callaway (2003), Cardoso et al (2007), Rabaut et al (2007) Biotic provision of 3D structure), both above and below sediment habitat heterogeneity and physical structure enhance diversity and recruitment tube-building species, seagrasses Featherstone and Risk (1977), Woodin (1978Woodin ( , 1981, Eckman (1985), Luckenbach (1986) Carey (1987) Woodin and Jackson (1979), Wilste (1980), Hunt et al (1987), Woodin et al (1993) Holme (1950), Elmgren et al (1986), Hardege et al (1998) invertebrates, especially higher on the shore where physical stress is greatest (Thompson et al 1996, Bertness et al 1999, Jenkins et al 1999a, Leonard 1999, Moore et al 2007). Intertidal canopy algae vary little in species composition across the Atlantic.…”