Auxiliary materials for Paper 2005gb002557 Wintertime phytoplankton bloom in the Subarctic Pacific supported by continental margin iron Phoebe J. Lam1,2, James K.B. Bishop1, Cara C. Henning3, Matthew A. Marcus4, Glenn A. Waychunas1 & Inez Y. Fung3 1. Earth Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA 2. Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94720, USA 3. Berkeley Atmospheric Sciences Center, University of California, Berkeley, Berkeley, CA 94720, USA 4. Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA Lam, P. J., J. K. B. Bishop, C. C. Henning, M. A. Marcus, G. A. Waychunas, and I. Y. Fung (2006), Wintertime phytoplankton bloom in the subarctic Pacific supported by continental margin iron, Global Biogeochem. Cycles, 20, GB1006, doi:10.1029/2005GB002557. Introduction The auxiliary materials provide an extensive description of the methods employed for our analysis, and comprise a text file, three tab-delimited tables, and five figures. These files are meant to be digested together as a methods manuscript to accompany the main manuscript. File 1. 2005gb002557-text01.txt: This file consists of the main prose of the methods description as well as references. We devote the bulk of this supplemental section to a detailed description of the collection, analysis, and quantification of X-Ray Fluorescence (XRF) data. We also provide brief descriptions of sample collection and selection, X-ray Absorption Spectroscopy (XAS) data collection and analysis, Scanning Transmission X-Ray Microscopy (STXM), and the ocean general circulation model. File 2. 2005gb002557-ts01.txt: "XRF data analysis: >53 um sample parameters" 2.1. Column "SampleID", unique sample identifier. the "p" at the end of the sample number denotes prefilter (>53um). 2.2. Column "Station", gives station ID. "OSP", "P16", and "P4" are from the Subarctic Pacific. "55S" is from the Southern Ocean. 2.3. Column "Month", the month and year of sampling. 2.4. Column "Depth", the depth at which the sample was collected, in m. 2.5. Column "Detectorwindow", the type of window in front of the detector. 2.6. Column "Fe_scaling_factor", the ratio of Fe counts between the sample's standard and the reference standard. 2.7. Column "Ca_scaling_factor", the ratio of Ca counts between the sample's standard and the reference standard. 2.8. Column "Bias_factor", the ratio of ICP-MS bulk to XRF-determined concentrations of Ca. 2.9. Column "Equiv_Vol_Filt", the equivalent volume filtered is the fraction of XRF map to MULVFS filter area multiplied by the total volume filtered for the MULVFS sample, in mL. #Parameters specific to the processing of samples run in July 2003 (BT1). *Gain on I0 increased 10x. File 3. 2005gb002557-ts02.txt: "XRF data analysis: >53 um mesh parameters". All counts are scaled to account for differences in detector configuration and normalized by I0, dwell time. 3.1. Column "Mesh_DetectorWindow", describes the mesh used ("SOFEX" used in the Southern Ocean, "OSP" used in the Subarctic Pacific), as well as the type of window in front of the detector. 3.2. Column "Ti_threshold", the 10th percentile of Ti counts for mesh determination, in counts per second (cps). 3.3. Column "Cr_background", the mean count rate in the Cr channel in "hole" regions of the mesh, in cps. 3.4. Column "Mn_background", the mean count rate in the Mn channel in "hole" regions of the mesh, in cps. 3.5. Column "Ca_background", the mean count rate in the Ca channel in "hole regions of the mesh, in cps. 3.6. Column "Total_background", the mean count rate in the "Total" channel in "hole" regions of the mesh, in cps. 3.7. Column "Fe_background", the mean count rate in the "Fe" channel in "hole regions of the mesh, after noise removal, in cps. 3.8. Column "Ti_background", the 5th percentile of Ti counts, in cps. 3.9. Column "CrMn", the Cr:Mn ratio in the mesh, after background Cr,Mn were removed. 3.10. Column "MnFe", the Mn:Fe ratio in the mesh, after removing noise Fe and background Mn and Fe. 3.11. Column "TiFe", the Ti:Fe ratio in the mesh, after removing noise Fe and background Ti and Fe. Used for BT1 only. 3.12. Column "Median_mesh_Mn", the median count rate of Mn in the mesh, in cps. 3.13. Column "Median_mesh_Ti", the median count rate of Ti in the mesh, in cps. Used for BT1 only. 3.14. Column "Max_Mn", the maximum count rate for Mn in the mesh, in cps. 3.15. Column "Max_Mnthresh", the Mn threshold for the determination of mesh Fe, in cps. 3.16. Column "Max_Ti", the maximum count rate for Ti in the mesh, in cps. Used for BT1 only. 3.17. Column "Max_Tithresh", the the Ti threshold for the determination of mesh Fe, in cps. Used for BT1 only. 3.18. Column "Median_mesh_Fe", the median Fe count rate in the mesh, in cps. 3.19. Column "Median_corrected_Fe", the median of corrected Fe counts after applying our correction algorith, in cps. 3.20. Column "Fe_Detection_Limit_cps", the Fe detection limit is 3 times the standard deviation of corrected Fe counts for the mesh blanks, in cps. 3.21. Column "Fe_Detection_Limit_umol", the Fe detection limit, in umol Fe/um2. File 4. 2005gb002557-ts03.txt: "XRF data analysis: 1-53 um sample parameters" 2.1. Column "SampleID", unique sample identifier. the "p" at the end of the sample number denotes prefilter (>53um). 2.2. Column "Station", gives station ID. "OSP" is Ocean Station Papa, "55S" is from the Southern Ocean. 2.3. Column "Month", the month and year of sampling. 2.4. Column "Depth", the depth at which the sample was collected, in m. 2.5. Column "Ca_attenuation_factor", the ratio of ICP-MS bulk to XRF-determined concentrations of Ca. 2.6. Column "Fe_attenuation_factor", derived from the Ca attenuation factor (see text). 2.7. Column "Equiv_Vol_Filt", the equivalent volume filtered is the fraction of XRF map to MULVFS filter area multiplied by the total volume filtered for the MULVFS sample, in mL. File 5. 2005gb002557-fs01.jpg: FeKa maps through data analysis steps for a representative sample (96006p, OSP, 71m) mapped in July 2003. The color bar is counts per second (cps) in the FeKa ROI; the scale is truncated at 5000 cps to accentuate the lower levels of Fe. a. I0- and dwell-time- normalized FeKa. b. Noise-corrected Fe. c. Background-subtracted Fe. d. Mesh-subtracted ("corrected") Fe. The holes in the mesh visible in a-c are 53 um. File 6. 2005gb002557-fs02.jpg: Ti XRF map of SOFeX mesh blank showing Ti threshold (10th percentile) in white, outlining the "hole" regions. Ti counts are scaled and normalized by I0 and dwell time. File 7. 2005gb002557-fs03.jpg: Cr XRF maps of SOFeX mesh blank. a. CrKa counts. b. CrKa, with background-Cr and mesh-Cr subtracted. Counts are in raw form (not normalized by dwell time or I0). File 8. 2005gb002557-fs04.jpg: Determination of Fe noise function using sample Jul96006p (OSP, 71m) and Cr as a noise diagnostic. a. Noise-Cr (blue +); mean noise-Cr in each 16,000-count bin (black o); Cr noise function (black line) is the linearly-interpolated noise-Cr; Cr noise function removed from noise-Cr data (red dots). b. raw Fe counts (blue +); mean noise-Fe (black o) and Fe noise function (black line) are the mean noise-Cr and Cr noise function multiplied by 2.5 scaling factor to fit to Fe; Fe noise function removed from Fe data (red dots). File 9. 2005002557-fs05.jpg: Sensitivity of Fe hotspot threshold definitions. Hotspot thresholds superimposed on XRF Fe map for Jul96006p (OSP, 71 m, >53 um); a. contour at hotspot threshold of 5 times detection limit (DL); b. contour at 10 x DL; c. contour at 15 x DL.