Submicron-scale spectroscopic analyses of chalcopyrite grain boundaries. A) A photograph of the inner chimney wall after cutting with a precision diamond wire saw. B, C) Elemental mapping of chalcopyrite grain boundaries obtained by synchrotron-based X-ray fluorescence analysis (XRF) from the regions with yellow rectangles in a. RGB diagrams are shown by synthesizing the three colors. D) A photograph of chalcopyrite grain boundaries with points analyzed by an infrared (IR) microscope. E) Optical photothermal infrared (O-PTIR) spectra of the points in d and cultured cells of Nanobdella aerobiophila strain MJ1^T (= JCM33616^T) and Metallosphaera sedula strain MJ1HA (=JCM33617) for an archaeal reference and Shewanella oneidensis strain MR-1^T (=ATCC 700550^T) for a bacterial reference. Peak assignment was based on refs [68–71] and references therein.