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.Sta015304150100170250320500Samples
093.3 028.0 X X 2
093.3 030.0 X X XXXXXX8
090.0 120.0 X X 2
090.0 090.0XX X XXXXXXX10
090.0 060.0XX X XXXXXXX10
090.0 053.0XX X XXXXXXX10
090.0 045.0 X X 2
090.0 037.0 X X 2
090.0 030.0 X X XXXXXX8
090.0 028.0 X X 2
086.7 033.0 X X 2
086.7 035.0 X X XXXXXX8
083.3 042.0 X X 2
083.3 040.6XX X 3
081.8 046.9 (SBB)X X XXXXXX8
080.0 051.0 X X XX 4
080.0 055.0 (CCE 2)XXX XXXXXX9
080.0 060.0 X X XXXXXX8
080.0 070.0 X X XXXXXX8
080.0 080.0 (CCE 1)X XXXXXXXX9
080.0 090.0 X X XXXXXX8
080.0 100.0XX X XXXXXXX10
Deep Station XX @ 35002

DIC CSV Column Headers

CSV Column HeaderDescription
Cast_IndexCalCOFI Hydrographic Database Cast Table Index; 1 = CalCOFI database's 1st cast record
Bottle_IndexCalCOFI Hydrographic Database Bottle Table Index; 1 = CalCOFI database's 1st bottle record
CruiseCalCOFI Cruise Designation with century prefix; CalCOFI 0901 = 200901
Depth(m)Sample Depth in meters
Line.Sta_IDCalCOFI Line & Station ID; Sta 80.55 = 080.0 055.0
Depth_IDUnique database index built from:Century-CruiseShip-Casttype-Julian DOY-UTC Time-LineSta-DepthDup-Record Indicator
DIC 1DIC Analysis - Dissolved Inorganic Carbon Measurement, first sample
DIC 2DIC Analysis - Dissolved Inorganic Carbon Measurement from a duplicate sample drawn from same depth as DIC 1
TA 1DIC Analysis - Total Alkalinity Measurement, first sample; same DIC bottle as DIC 1
TA 2DIC Analysis - Total Alkalinity Measurement from a duplicate sample drawn from same depth as TA 1
pH 1Spectrophotometrically measured pH per kilogram seawater
pH 2Spectrophotometrically measured pH per kilogram seawater from a duplicate sample drawn from same depth as pH 1
Salinity 1DIC Analysis - Salinity value from DIC 1 bottle
Salinity 2DIC Analysis - Salinity value from DIC 2 bottle
Temperature_degCCTD Temperature from Bottle Sample Depth
Bottle SalinityCalCOFI 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-thetaSigma-theta Density calculated from CalCOFI data
DIC Bottle_ID1DIC 1 Bottle Index Number
DIC Bottle_ID2DIC 2 Bottle Index Number
DIC Quality CommentQuality Control Comments on DIC samples after processing