Hydrothermal chimneys were collected by a ROV in 2016 from the Kairei and Pelagia vent fields along the Indian Ridge. Major element compositions of the chimney samples were determined by a combination of ICP emission and mass spectrometry. For semi-quantitative analysis of sulfide mineral distribution polished sections of the chimneys were investigated by optical and scanning electron microscopy and electron microprobe analyses. The abundance of bacterial and archaeal taxa was determined by sequencing of the 16S rRNA gene by Illumina MiSeq.

Sequence data have been deposited in the National Center for Biotechnology Information Sequence Read Archive (SRA) under accession no. SRP120106.Geochemical compositions are given in min.- max. values from interior to outer part of the sample.