\u2028In situ carbonate rocks were taken at sites with different seepage activity in 2017 (AT37-13) and 2018 (AT42-03) using HOV Alvin. These were used as control samples for two experiments: (1) Carbonate rocks, woods, and bones deployed for 7.4 years were collected across seepage gradients at Mound 12 using HOV Alvin (Colonization 7.4 years), and (2) Carbonate rocks were moved by the HOV to different seepage conditions with exposure for 17 months (Transplant 17 months).
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All substrates were photographed intact upon recovery, and wrapped in aluminum foil to determine the surface area. Before preserving, the sample was kept cold and animals were picked to sample tissue for isotope analysis (see files \u201cAT37-13 and AT42-03 Hard substrate isotopes\u201d for isotopic data).
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The remaining sample was sieved through 0.3 mm mesh, separating the sample in two fractions (a fine fraction with the meiofauna, and a coarser one with the macrofauna), both preserved in 96% Ethanol. In the laboratory, the samples were washed in distilled water and sorted, and the animals were identified to the lowest level possible, counted and preserved in 96% Ethanol.
Substrates were sorted and the fauna was identified to the lowest taxonomic level possible. Annelida and Mollusca, the most abundant groups, were identified at the family level. Crustacea was identified at the order or infraorder level, Cnidaria was identified at the order level, and Echinodermata was identified at the class level. The least abundant groups, Nemertea, Platyhelminthes and Pycnogonida, were identified to phylum.
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Note: Not all samples were used for density analyses, thus some do not have surface area values.
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BCO-DMO Processing:\u00a0
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\n- Modified parameter names to comply with database requirements
\n- Added sampling latitude and longitude
\n- Changed , to ; to comply with database requirements
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