Description/methods for parameters measured:
\nC parameters performed by Dr. Wei-Jun Cai\u2019s group for:
\nTA - Open cell Gran titration with semi-automatic\u00a0AS-ALK2 Apollo Scitech titrator;
\npH - glass electrode, NBS buffers;
\nDIC - infrared CO2 analyzer (AS-C3, Apollo Scitech).
\nUse Dickson CRM for calibration. DIC/TA samples were filtered (0.45um) and fixed with 100 ul of saturated mercury bichloride.
\nUse the methods of Gran (1952) and Huang, et al. (2012).
Fe parameters:
\nThe method of Stookey (1972) is used to determine dissolved Fe(II) and on addition if hydroxylamine Fe total. Fe(III) is determined by difference. Modified and calibrated by many including Lewis et al (2007) and MacDonald et al (2014). Typically, triplicate measurements performed.
Dissolved Mn parameters:
\nThe porphyrin spectrophotometric method of Madison et al (2011) measures dissolved Mn(II), Mn(III) bound to weaker ligands and total Mn. Method includes calibration and intercomparison of totals with other instrumentation (ICP, AA).\u00a0 Detection limit is 0.050 micromolar. Detection limit (DL) is 50 micromolar with a 1 cm path length cell.
Modification of Madison for Mn(III) bound to strong ligands by adding a reducing agent to a separate subsample with the porphyrin to obtain total Mn. Mn(III) bound to strong ligand complexes is determined by difference. Typically, triplicate measurements performed. Detection limit is 3.0 nanomolar.
\nMnOx on unfiltered samples:
\nThe leucoberbelein blue method is that of Altmann (1972) and Krumblein and Altmann (1973) in 1 cm cells, but can be modified for longer path length cells.
S parameters:
\nO2, H2S and polysulfides by the voltammetry method of Luther et al (2008).
\nA flow cell was also used to collect in situ O2 and H2S data as well as some additional samples. Analysis by voltammetry (Luther et al, 2008).
\nSolid and nanoparticulate S8 (Y\u00fccel et al 2010 and Findlay et al 2014).
\nTypically, triplicate measurements performed.\u00a0
In situ\u00a0pump profiler cast refers to profiling with a pump profiler for O2\u00a0and H2S using solid state gold-amalgam electrodes for voltammetry (Luther et al, 2008; Analytical Instrument Systems DLK-60) along with a temperature and salinity sensor from YSI. Water was pumped aboard to make measurements on discrete samples for Mn and Fe speciation as well.\u00a0
\nMethods papers used in this project (full citations in Related Publications section)
\nDissolved Mn speciation parameters:
\nMadison et al. (2011)
Madison et al. (2013)\u00a0
\nOldham et al. (2015)
\nOldham et al. (2017)
\n[[\u00a0Here, we modified the method of Madison et al. (2011) for water column samples to achieve a detection limit of 3.0 nM (3 times the standard deviation of a blank) by using a 100-cm liquid waveguide capillary cell and the addition of a heating step as well as a strong reducing agent for Mn Speciation [Mn3+ = MnT \u2013 Mn2+]. See Table 1 in this paper for recovery tests. As weak Mn(III)-L complexes could not be measured in our previous work (Oldham et al, 2015; paper above), this method was used throughout this cruise. ]]
MnOX solids:
\nAltmann (1972)
Krumbein & Altmann (1973)
\nDissolved Fe speciation parameters:
\nStookey (1970)
Lewis et al. (2007)
\nO2 and H2S, polysulfides:
\nLuther et al. (2008)
Luther et al. (2013)
\nS8:
\nY\u00fccel et al. (2010)
pH and inorganic carbon parameters:
\nGran (1952)
Huang & Cai (2012)
Data from in situ pump profiler system\u00a0collected on cruise HRS1415.
\nSee Related Publicatons (below) for field papers published as a result of this project (methods included).
BCO-DMO Processing:
\n- added column\u00a0for cast (was contained in header rows);
\n- modified parameter names to conform with BCO-DMO naming conventions;
\n- formatted date to mm/dd/yyyy to match CTD dataset;
\n- replaced blanks/missing data with \"nd\" (\"no data\");
\n- replaced \"ND\" (in all caps) with \"not_detected_or_BDL\";
\n- replaced \"NA\" (in all caps) with \"not_analyzed\";
\n- coverted lat and lon from degrees and decimal minutes to decimal degrees;
\n- added date-time in ISO8601 format using original date and time_GMT fields.