Data Processing:
Data processing was done with ESI SC version 2.9.0.380.

Data Quality Flags:
The standard Ocean Data View (ODV) / SeaDataNet qualifying flags were used (reference all flags at http://vocab.nerc.ac.uk/collection/L20/current/).

1: Good Value: Good quality data value that is not part of any identified malfunction and has been verified as consistent with real phenomena during the quality control process. [Used when replicates were in good agreement].
2: Probably Good Value: Data value that is probably consistent with real phenomena but this is unconfirmed. [Used when data is oceanographically consistent but no replicates.]
3: Probably Bad Value: Data value recognized as unusual during quality control that forms part of a feature that is probably inconsistent with real phenomena. [Used when data not oceanographically consistent but replicate analyses agreed.]
4: Bad Value: An obviously erroneous data value. [Used when replicates did not agree].
5: Changed Value: Data value adjusted during quality control. [Not used].
6: Value Below Detection Limit: The level of the measured phenomenon was too small to be quantified by the technique employed to measure it. Values are replaced with ‘nd’ for ‘not detectable’. [See Table 1 for detection limits.]
7: Value in Excess: The level of the measured phenomenon was too large to be quantified by the technique employed to measure it. The accompanying value is the measurement limit for the technique. [Not used].
8: Interpolated Value: This value has been derived by interpolation from other values in the data object. [Not used].
9: Missing Value: The data value is missing. Any accompanying value will be a magic number representing absent data. [Not used].
A: Value Phenomenon Uncertain: There is uncertainty in the description of the measured phenomenon associated with the value such as chemical species or biological entity. [Not used.]

Description of Table 1 (see Supplemental Files for the actual table): Average concentration ± standard deviation for relevant quality control samples (QCs), reference materials, and Milli-Q (MQ) blanks during dissolved trace metal analyses. A set of air blanks was run every seaFAST run. The limit of detection (LOD) for each dissolved element was calculated as 3 times the average SD of the air blanks. The QC surface seawater used was from the North Pacific (NP) EXPORTS cruise in August 2018. Reference materials (SAFe S, GSP) with consensus values were used. Consensus values for SAFe S and GSP are available on the GEOTRACES website (https://www.geotraces.org/standards-and-reference-materials/). *Dissolved Co and Cu concentrations are reported for UV-oxidized samples only. **Consensus values were converted to units of nM (Mn, Fe, Ni, Cu, and Zn) or pM (Co, Cd, and Pb) using average seawater density of 1.025 kg/L.

BCO-DMO Processing:
- converted DATE field to YYYY-MM-DD format;
- added the ISO_DateTime_UTC field.