cruise 
Cruise identifier

unitless 
cruise_id 
ship 
Ship name

unitless 
ship 
ISO_DateTime_UTC 
Date and time formatted to ISO8601 standard. Format: yyyymmddTHH:MM:SSZ

unitless 
ISO_DateTime_UTC 
date 
Date; format: yyyymmdd

unitless 
date 
time 
Time; format: HH:MM

unitless 
time 
latitude 
Latitude; positive values = North

decimal degrees 
lat 
longitude 
Longitude; positive values = East

decimal degrees 
lon 
depth_sample 
The depth at which the niskin bottle was closed (from which seawater was collected for analysis)

meters (m) 
depth 
depth_ctd 
Depth of the nearest CTD sensor measurements, extracted from the continuous CTD files (where bottle files were not available)

meters (m) 
depth 
pressure_ctd 
Pressure

decibars (db) 
press 
temperature_ctd 
Temperature measured by CTD

degrees Celsius 
temp 
salinity_ctd 
Salinity measured by CTD

psu 
sal 
oxygen_ctd 
Oxygen measured by CTD

milliliters per liter (ml/l) 
O2 
fluorescence_ctd 
Fluorescence measured by CTD

milligrams per cubic meter (mg/m3) 
fluor 
potdens_calc 
Potential density, calculated from temperature and salinity

kilograms per cubic meter (kg/m3) 
density 
MLD_calc 
Calculated mixed layer depth at each profile station, defined as the closest depth to the surface at which potential density is greater by greater than or equal to 0.03 kg/m3 than the value at a reference depth of 11 m (the shallowest depth common to every CTD station), based on the criterion of de Boyer Montégut et al. (2004).

meters (m) 
depth_mixed_layer 
d15N_avg_nitrate_nitrite 
Average d15N. d15N is the nitrogen isotopic composition of a sample (nitrate+nitrite) expressed in delta notation (d15N in units of per mil, ‰) relative to atmospheric N2, where d15N = {[(15N/14N)sample/(15N/14N)atmN2] – 1} × 1000

per mil vs AIR 
del15N_NO3NO2 
d15N_stdev_nitrate_nitrite 
Standard deviation of d15N (nitrate+nitrite)

per mil vs AIR 
del15N_NO3NO2 
d15N_n_nitrate_nitrite 
Number of replicate measurements of d15N (nitrate+nitrite)

unitless 
num_reps 
conc_avg_nitrate_nitrite 
Concentration of nitrate+nitrite in a seawater sample

micromolar (uM) 
NO3_NO2 
conc_stdev_nitrate_nitrite 
Standard deviation of nitrate+nitrite concentration

micromolar (uM) 
NO3_NO2 
conc_n_nitrate_nitrite 
Number of replicate measurements of nitrate+nitrite concentration

unitless 
num_reps 
d15N_avg_nitrate 
Average d15N. d15N is the nitrogen isotopic composition of a sample (nitrate only) expressed in delta notation (d15N in units of per mil, ‰) relative to atmospheric N2, where d15N = {[(15N/14N)sample/(15N/14N)atmN2] – 1} × 1000

per mil vs AIR 
dN15_NO3 
d15N_stdev_nitrate 
Standard deviation of d15N (nitrate only)

per mil vs AIR 
dN15_NO3 
d15N_n_nitrate 
Number of replicate measurements of d15N (nitrate only)

unitless 
num_reps 
conc_avg_nitrate 
Concentration of nitrate in a seawater sample

micromolar (uM) 
NO3 
conc_stdev_nitrate 
Standard deviation of nitrate concentration

micromolar (uM) 
NO3 
conc_n_nitrate 
Number of replicate measurements of nitrate concentration

unitless 
num_reps 