Colonists were collected on experimental surfaces (sandwiches) constructed from six 0.7-cm-thick Lexan plastic plates separated by 1 cm spacers, creating a lattice 10 cm on a side (Bayer et al, 2011; note in 1998 colonists were collected on basalt blocks). Sandwiches were deployed and recovered by the submersible Alvin or ROV Jason. Deployment durations were 4, 2, 11, 11, 43, 10, and 29 months respectively for the recoveries at 9, 11, 22, 33, 96, 106, and 135 months after an eruption that took place in January 2006. The thermal environment at the base of each sandwich was measured with the Alvin (or Jason) temperature probe on deployment and recovery for ca 1–2 min until a clear maximum value was obtained.
Species abundance was assessed on three replicate sandwiches for each treatment (e.g., from one habitat within a site at a particular recovery date). On recovery, each sandwich was placed in individual collection compartments for transport back to the ship. On board, sandwiches and their attached colonists were preserved in 80% ethanol, as were any individuals that had become detached in the compartment and were retained on a 63-µm sieve. In the laboratory, each surface was examined under a dissecting microscope and all metazoan colonists (including detached individuals >1 mm) were enumerated and identified to species if possible. Additional identifications based on genetic barcoding are in progress using support from other sources. Those data will be added in future.