NanoSIMS_Cs+beam_biofilm-growth_days 7&14

Data for Figures 1, 2 and S5 in paper: "Elucidating Heterogeneous Iron Biomineralization Patterns in a Denitrifying As(III)-Oxidizing Bacterium: Implications for Arsenic Immobilization"Sample preparation:<br>Acidovorax sp. strain ST3 cells were grown anoxically in low phosphate medium with ¹³C-labelled acetate (10 mM), nitrate (10 mM), arsenite (0.5 mM) and Fe(II) (4 mM) for 7 or 14 days. Si wafers were introduced in the incubation bottles, to support surface colonization and precipitation of biominerals. The samples were fixed with glutaraldehyde and dehydrated with ethanol solutions, air-dried and Pt coated (10 nm). NanoSIMS analysis details:<br>NanoSIMS analysis was performed in a NanoSIMS 50L ion microprobe (CAMECA) using a Cs⁺ primary ion beam at 16 keV. The beam current was between 0.131-1.435 pA with a spatial resolution from 150-300 nm (D1 aperture= 4-2). The negative secondary ions detected simultaneously were:¹²C, ¹³C, ¹²C¹⁴N, ²⁸Si, ⁵⁶Fe¹²C, ⁵⁶Fe¹⁶O and ⁷⁵As. An ion-induced SE image was also obtained. The regions of analysis (ROIs) were implanted with Cs⁺ ions to a dose of 1x10¹⁷ ions cm^-2 to remove the Pt coating and reach steady state. The dwell time for image collection was between 2000-5000 µs px^-1. The CAMECA mass resolving power (MRP) was &gt;7000 using ES=3 and AS=2. The image pixel sizes were 128 x 128 or 256 x 256. The field of view of these nanoSIMS ions images was 30-60 µm. The data was processed using the L’image software (Larry Nittler, Carnegie Institution of Washington) and the plugin OpenMIMS for ImageJ (www.nrims.harvard.edu). <br>About the files: Three and nine nanoSIMS files are presented for days 7 and 14 of incubation, respectively. Files are presented in the .im raw nanoSIMS file format with additional complementary png images showing all the masses for each area of interest (AOI). All normalised counts and AOI details are compiled in the Excel spreadsheet.