TEM images of microbial forms in Fe–Si–Mn oxyhydroxides from Franklin Seamount. (a) and (b) Typical fragments of anhedral agglomerates of amorphous iron oxyhydroxides, sample M2202–2A-1 (106920), height of images 2.6 μm. (c) Pseudo? branching filament, sample M2022-3B (106926), height of image 13 μm. (d) Filament exhibiting hollow structure, sample M2192 loc. 1 (106848), height of image 2.6 μm. The walls consist of regular bands of amorphous iron-silica oxyhydroxides. (e) Braided filament, sample M2202-2a-1 (106920), height of images 4 μm. (f) Amorphous iron oxyhydroxides (see arrow) agglomerated on a typical filament, sample M2202-2a-1 (106920), height of images 5 μm.