Data are averages of samples replicates, the number of which is indicated as a data column. Standard deviation of replicates is included as a data column as well. Data has been visually QA/QC. Samples runs results are compared against NIST 'Buffalo River sediment' reference material and Perkin Elmer Acetanylide runs.

Data processing and calibration is performed in Matlab using a script that generates a data report that includes the C and N content in mg for each filter replicate sample. For details on processing and calibration, please see the accompanying Supplemental Documents (kn199-04_POC_data_process.pdf)

BCO-DMO Processing Notes:
- Parameter header names were renamed to BCO-DMO convention
- Edited blank data fields and data reported as -999 to 'nd'
- Edited time to remove colons and drop unused seconds
- Edited precision of lat/lon to four decimals.
- Edited precision of POC, PON, PON_sd and POC_sd to one decimal.
- Removed the following header information from the file. Where necessary the information was incorporated into BCO-DMO metadata fields and retained entirely as 'additional information':

NOTE: The value -999 in the original file "sample" parameter, was used represent samples taken with a surface pump. This value was set by the PI, to indicate NASA's pump. However, correspondence with the PI on 2013.01.12, has corrected header note regarding sample numbers.

Therefore, the comment retained in the header has been edited to the following text, as per the PI, and sample numbers of -999 have been changed to 'nd' and additional metadata in the sample number parameter indicates that samples wtih GEOTRACES numbers had corresponding pigment samples taken, those with 'nd' did not:

# Samples from station 1 with 0 depth were collected with WHOI's GEOTRACES pump
# Sample numbers for stations > 1 with depth = 0 were collected with NASA's
# surface peristaltic pump

Additional GEOTRACES Processing: After the data were submitted to the International Data Management Office, BODC, the office noticed that important identifying information was missing in many datasets. With the agreement of BODC and the US GEOTRACES lead PIs, BCO-DMO added standard US GEOTRACES information, such as the US GEOTRACES event number, to each submitted dataset lacking this information. To accomplish this, BCO-DMO compiled a 'master' dataset composed of the following parameters: station_GEOTRC, cast_GEOTRC (bottle and pump data only), event_GEOTRC, sample_GEOTRC, sample_bottle_GEOTRC (bottle data only), bottle_GEOTRC (bottle data only), depth_GEOTRC_CTD (bottle data only), depth_GEOTRC_CTD_rounded (bottle data only), BTL_ISO_DateTime_UTC (bottle data only), and GeoFish_id (GeoFish data only). This added information will facilitate subsequent analysis and inter comparison of the datasets.

Bottle parameters in the master file were taken from the GT-C_Bottle_GT10, GT-C_Bottle_GT11, ODF_Bottle_GT10, and ODF_Bottle_GT11 datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the Event_Log_GT10 and Event_Log_GT11 datasets. McLane pump cast numbers missing in event logs were taken from the Particulate Th-234 dataset submitted by Ken Buesseler.

A standardized BCO-DMO method (called “join”) was then used to merge the missing parameters to each US GEOTRACES dataset, most often by matching on sample_GEOTRC or on some unique combination of other parameters.

If the master parameters were included in the original data file and the values did not differ from the master file, the original data columns were retained and the name of the parameters were changed from the PI-submitted names to the standardized master names. If there were differences between the PI-supplied parameter values and those in the master file, both columns were retained. If the original data submission included all of the master parameters, no additional columns were added, but parameter names were modified to match the naming conventions of the master file.

See the dataset parameters documentation for a description of which parameters were supplied by the PI and which were added via the join method.