Dissolved Inorganic Carbon (DIC)
CalCOFI collects samples for inorganic carbon and total alkalinity at specific stations throughout the cruise track. Seawater samples are collected from several depths, preserved and brought back to SIO for total inorganic carbon and total alkalinity analysis. These measurements allow the calculation of pH and pCO2. The objectives of these measurements are: first, the long-term characterization of the inorganic carbon system and its response to changing ocean climate, and second, measurements of pH in the coastal zone in order to monitor the anthropogenic impact on coastal ecosystems in the Southern California Bight.
DIC samples for Dave Keeling were also collected on CalCOFI stations 90.70, 90.90, & 90.120 from Sep 1986 (CalCOFI 8609NH) to Nov 2002 (CalCOFI 0211NH). In Aug 2008, DIC sampling restarted on 7 stations, grew to 10 stations in Jan 2011, and currently DIC has expanded substantially (see map & table below). Dissolved inorganic carbon (DIC) and total alkalinity (TA) data have only been integrated into the CalCOFI hydrographic dataset since Aug 2008, then Jan 2009 through presently. Similarly, pH data have only been integrated into the CalCOFI hydrographic dataset since April 2014.
Dissolved Inorganic Carbon & Total Alkalinity Data CSV’s
200808, 200901 – 201507
CSV’s extracted from the CalCOFI MS Access Bottle Database
Station 90 90 Data
198402 – 202107
Map of CalCOFI standard sampling pattern (75 stations) with stations where DIC samples are collected colored in blue or orange. See table below for more details on depths sampled.
DIC Sampling Information
DIC Sampling Depths by Station (used since 2014)
| Line.Sta | 0 | 15 | 30 | 41 | 50 | 100 | 170 | 250 | 320 | 500 | Samples |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 093.3 028.0 | X | X | 2 | ||||||||
| 093.3 030.0 | X | X | X | X | X | X | X | X | 8 | ||
| 090.0 120.0 | X | X | 2 | ||||||||
| 090.0 090.0 | XX | X | X | X | X | X | X | XX | 10 | ||
| 090.0 060.0 | XX | X | X | X | X | X | X | XX | 10 | ||
| 090.0 053.0 | XX | X | X | X | X | X | X | XX | 10 | ||
| 090.0 045.0 | X | X | 2 | ||||||||
| 090.0 037.0 | X | X | 2 | ||||||||
| 090.0 030.0 | X | X | X | X | X | X | X | X | 8 | ||
| 090.0 028.0 | X | X | 2 | ||||||||
| 086.7 033.0 | X | X | 2 | ||||||||
| 086.7 035.0 | X | X | X | X | X | X | X | X | 8 | ||
| 083.3 042.0 | X | X | 2 | ||||||||
| 083.3 040.6 | XX | X | 3 | ||||||||
| 081.8 046.9 (SBB) | X | X | X | X | X | X | X | X | 8 | ||
| 080.0 051.0 | X | X | X | X | 4 | ||||||
| 080.0 055.0 (CCE 2) | X | X | X | X | X | X | X | X | X | 9 | |
| 080.0 060.0 | X | X | X | X | X | X | X | X | 8 | ||
| 080.0 070.0 | X | X | X | X | X | X | X | X | 8 | ||
| 080.0 080.0 (CCE 1) | X | X | X | X | X | X | X | X | X | 9 | |
| 080.0 090.0 | X | X | X | X | X | X | X | X | 8 | ||
| 080.0 100.0 | XX | X | X | X | X | X | X | XX | 10 | ||
| Deep Station | XX @ 3500 | 2 |
DIC CSV Column Headers
| CSV Column Header | Description |
|---|---|
| Cast_Index | CalCOFI Hydrographic Database Cast Table Index; 1 = CalCOFI database's 1st cast record |
| Bottle_Index | CalCOFI Hydrographic Database Bottle Table Index; 1 = CalCOFI database's 1st bottle record |
| Cruise | CalCOFI Cruise Designation with century prefix; CalCOFI 0901 = 200901 |
| Depth(m) | Sample Depth in meters |
| Line.Sta_ID | CalCOFI Line & Station ID; Sta 80.55 = 080.0 055.0 |
| Depth_ID | Unique database index built from:Century-CruiseShip-Casttype-Julian DOY-UTC Time-LineSta-DepthDup-Record Indicator |
| DIC 1 | DIC Analysis - Dissolved Inorganic Carbon Measurement, first sample |
| DIC 2 | DIC Analysis - Dissolved Inorganic Carbon Measurement from a duplicate sample drawn from same depth as DIC 1 |
| TA 1 | DIC Analysis - Total Alkalinity Measurement, first sample; same DIC bottle as DIC 1 |
| TA 2 | DIC Analysis - Total Alkalinity Measurement from a duplicate sample drawn from same depth as TA 1 |
| pH 1 | Spectrophotometrically measured pH per kilogram seawater |
| pH 2 | Spectrophotometrically measured pH per kilogram seawater from a duplicate sample drawn from same depth as pH 1 |
| Salinity 1 | DIC Analysis - Salinity value from DIC 1 bottle |
| Salinity 2 | DIC Analysis - Salinity value from DIC 2 bottle |
| Temperature_degC | CTD Temperature from Bottle Sample Depth |
| Bottle Salinity | CalCOFI Salinity Measurement from DIC Depth |
| Bottle O2(ml_L) | CalCOFI Oxygen Measurement in milliliters/liter, from DIC Depth |
| Bottle O2(æmol/Kg) | CalCOFI Oxygen Measurement in umoles/Kg, from DIC Depth |
| Sigma-theta | Sigma-theta Density calculated from CalCOFI data |
| DIC Bottle_ID1 | DIC 1 Bottle Index Number |
| DIC Bottle_ID2 | DIC 2 Bottle Index Number |
| DIC Quality Comment | Quality Control Comments on DIC samples after processing |