| Parameter | Description | Units |
|---|
| event | unique sampling event composite of GMT yday and time | YYyday_hhmm |
| cast | CTD cast number | dimensionless |
| bot | Niskin bottle number | dimensionless |
| sample_ID | unique isotope sample ID | dimensionless |
| press | pressure, from CTD | decibars |
| depth | depth; calculated from pressure | meters |
| NO3_HOT | nitrate from the HOT database | micromole/kilogram |
| PO4_HOT | phosphate from the HOT database | micromole/kilogram |
| temp | temperature, from CTD, ITS-90 | degrees Celsius |
| sal | salinity, from CTD, PSS-78 (PSU) | dimensionless |
| sigma_0 | sigma-theta (potential density) | kilograms/meter^3 |
| d15NO3_AIR | delta 15N of nitrate vs. AIR std. | permil |
| d15NO3_sd | delta 15N of nitrate (stdev) | permil |
| d18NO3_VSMOW | delta 15N of nitrate vs. VSMOW std. | permil |
| d18NO3_sd | delta 18O of nitrate (stdev) | permil |
| d15N_18O | ratio of isotopic analysis D(15,18) | permil |
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