Table 1. Sample information on geographical location, year of sampling, sample area, and volume of sediment.

Habitat	pompei worm communities					tubeworm communities						mussel communities			bare basalt communities
Samples	P1	P2	P3	P4	P5	T1	T2	T3	T4	T5	T6	M1	M2	M3	B1	B2	B3	B4
Site	Michel's	Alvinella	Bio9	M-Vent	M-Vent	Tica	Tica	Tica	Riftia	Riftia	Riftia	Mussel	Mussel	Mussel	near	near	near	near
	Vent	Pillar							Field	Field	Field	Bed	Bed	Bed	Tica	Tica	Tica	A.Pillar
Latitide 9°50.	.709′N	.130′N	.335′N	.826′N	.826′N	.447′N	.447′N	.447′N	.705′N	.705′N	.705′N	.615′N	.613′N	.629′N	.447′N	.447′N	.447′N	.130′N
Longitude 104°17.	.585′W	.438′W	.474′W	.583′W	.583′W	.493′W	.493′W	.493′W	.493′W	.493′′W	.493′W	.509′W	.504′W	.512′W	.493′W	.493′W	.493′W	438′W
Depth (m)	2507	2502	2508	2508	2508	2500	2500	2500	2500	2500	2500	2503	2503	2503	2500	2500	2500	2502
Year of Sampling	2004	2004	2004	2004	2004	2001	2001	2002	2001	2001	2002	2002	2002	2002	2003	2003	2004	2004
Alvin dive #	4063	4065	4069	4070	4072	3731	3732	3846	3730	3734	3843	3845	3847	3852	3952	3952	4063	4064
Sample area (cm2)	113	343	56	36	17	600	300	700	1300	600	800	1370	770	630	454	263	270	369
Sediment (ml)	17	174	106	138	20	88	165	133	40	37	85	25	15	19	4.9	9.6	2.3	6.5

We named samples after habitat types and their foundation species (P pompei worm, T tubeworm, M mussel) or their substrate (B bare basalt); dominant foundation species at sites were Alvinella pompejana Debruyéres & Laubier 1980, Riftia pachyptila Jones 1981, and the mytilid mussel Bathymodiolus thermophilus Kenk & Wilson 1985. High temperature sulfide chimney habitats are not shown because not a single specimen was detected within these samples and this habitat type was therefore excluded from all analyses.