Surface and profile concentrations of trace metals and radionuclides near Station ALOHA

Trace element water samples from KM1513 were collected with the MIT Automated Trace Element (ATE) sampler, deployed with a teflon-coated wire from the ship’s deck for surface water samples (collected at roughly 10 m depth), and with the ATEs attached to PVC “Vanes” designed to prevent contamination from the ship’s steel wire for samples collected at greater depth. Samples were filtered at 0.4 μm immediately after collection through polycarbonate track etched filters (Nucleopore) into 250 mL HDPE bottles and acidified to 0.012 M hydrochloric acid (ultrapure by quadruple distillation in a Vycor still; ~pH 2) at sea. Sampling and filtration followed published protocols used previously at Station ALOHA, for direct comparison (Fitzsimmons et al., 2015). These casts mostly aligned with Niskin cast station locations, but in some cases did not.


Dataset Description
Trace element water samples from KM1513 were collected with the MIT Automated Trace Element (ATE) sampler, deployed with a teflon-coated wire from the ship's deck for surface water samples (collected at roughly 10 m depth), and with the ATEs attached to PVC "Vanes" designed to prevent contamination from the ship's steel wire for samples collected at greater depth.
Samples were filtered at 0.4 μm immediately after collection through polycarbonate track etched filters (Nucleopore) into 250 mL HDPE bottles and acidified to 0.012 M hydrochloric acid (ultrapure by quadruple distillation in a Vycor still; ~pH 2) at sea. Sampling and filtration followed published protocols used previously at Station ALOHA, for direct comparison (Fitzsimmons et al., 2015). These casts mostly aligned with Niskin cast station locations, but in some cases did not.

Acquisition Description
Thorium isotope samples were collected from the ship's Niskin bottle rosette, and in some cases, surface water (from roughly 15 m depth) was also collected using a Teflon diaphragm pump (Cole Palmer) operated from the ship's deck. Water was filtered at 0.45 μm using Acropak filter cartridges and acidified to 0.024 M HCl (~pH 1.5) at sea.
Surface samples for both trace elements and thorium isotopes were taken every 12 hours between July 25 and August 3, roughly at sunrise and sunset (Hawaii Standard Time). This timing was motivated to observe the maximum possible change in dissolved elemental concentrations since it coincides with the highest contrast in surface water biomass (maximum at sunset, minimum at sunrise). Depth profile samples for trace elements were collected on July 30 at 10:00 AM, except for the sample from 180 m, which was collected on August 2 at 4:00 PM, due to a misfiring of the original 180 m Vanes deployment. Thorium depth profile samples were collected on July 31 at 2:00 AM (station 43 of KM1513).
The elements Sc, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb from the Lagrangian sampling (KM1513) were analyzed at Texas A&M University using an offline SeaFAST-pico preconcentration system (ESI, Omaha, NE) and a Thermo Finnigan Element XR high-resolution inductively-coupled mass spectrometer (HR-ICP-MS) housed at the R. Ken Williams Radiogenic Isotope Facility. Notably, samples were not UV oxidized, and thus cobalt concentrations must be considered to be operationally defined ICP-labile cobalt (lCo). Accuracy was assessed by analyzing aliquots of the SAFe D1 seawater consensus standard. Precision is reported as error bars for each analysis and was assessed using the standard deviation of duplicate or triplicate analyses of all samples.
Note trace metal data that did not meet the principal of oceanographic consistency were marked in parentheses in the worksheet. These data could not be determined specifically to have been contaminated but we treat them with caution and they were not considered in the publication.
Thorium isotopes (232Th and 230Th) were analyzed at MIT by Fe co-precipitation from 4 L samples, acid digestion, anion exchange chromatography, and a Nu Plasma II ICP-MS. Accuracy was assessed by analysis of the SWS2010-1 standard (Anderson et al., 2012) (Table 2) as well as an in-house thorium isotope standard (MITh-1). Reported uncertainty for thorium isotopes represents the uncertainty in isotope ratios measured on the ICP-MS.
Select samples were also analyzed for dissolved aluminum (dAl) concentrations. These samples were sub-sampled from the water filtered from the ATE sampler, filtered directly into 125 mL acid washed PMP bottles and acidified to 0.006 M HCl and microwaved for 58 seconds/125mL of sample. These samples were then acidified to 0.012 M HCl (~pH 2) and stored for shipboard analysis on a later cruise (R/V Revelle cruise RR1815 in November 2018) for dAl using flow injection analyses. Replicate standards were used to assess precision and accuracy of this method, and reported errors are the relative standard deviation of standard analyses.

Processing Description
No data processing were necessary.    Center will design and conduct novel research, broker partnerships, increase diversity of human resources, implement education and outreach programs, and utilize comprehensive information about microbial life in the sea. The Center will bring together teams of scientists, educators and community members who otherwise do not have an opportunity to communicate, collaborate or design creative solutions to long-term ecosystem scale problems. The Center's research will be organized around four interconnected themes: (Theme I) microbial biodiversity, (Theme II) metabolism and C-N-P-energy flow, (Theme III) remote and continuous sensing and links to climate variability, and (Theme IV) ecosystem modeling, simulation and prediction. Each theme will have a leader to help coordinate the research programs and to facilitate interactions among the other related themes. The education programs will focus on pre-college curriculum enhancements, in service teacher training and formal undergraduate/graduate and post-doctoral programs to prepare the next generation of microbial oceanographers. The Center will establish and maintain creative outreach programs to help diffuse the new knowledge gained into society at large including policymakers. The Center's activities will be dispersed among five partner