NOAA DATA REPORT ERL PMEL-

**CHEMICAL AND HYDROGRAPHIC MEASUREMENTS FROM THE EQUATORIAL PACIFIC
DURING BOREAL AUTUMN, 1992**

Marilyn F. Lamb^1^

Tom Lantry^2^

James Hendee^2^

Kristy E. McTaggart^1^

Paulette P. Murphy^1^

Richard A. Feely^1^

Rik Wanninkhof^2^

Frank J. Millero^3^

Robert H. Byrne^4^

Edward T. Peltzer^5^

Denis Frazel^2^

^1^ NOAA, Pacific Marine Environmental Laboratory (PMEL), 7600 Sand
Point Way N.E., Seattle, WA 98115-0070

^2^ NOAA, Atlantic Oceanographic and Meteorological Laboratory (AOML),
4301 Rickenbacker Causeway, Miami, FL 33149

^3^ Rosenstiel School of Marine and Atmospheric Sciences (RSMAS),
University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149

^4^ Department of Marine Science, University of South Florida, 140 7th
Avenue South, St. Petersburg, FL 33701

^5^ Department of Chemistry, Woods Hole Oceanographic Institution, Woods
Hole, MA 02543

August 1995

Contribution No. 1605 from NOAA/Pacific Marine Environmental Laboratory

NOTICE

> Mention of a commercial company or product does not constitute an
> endorsement by NOAA/ERL. Use of information from this publication
> concerning proprietary products or the tests of such products for
> publicity or advertising purposes is not authorized.

Contribution No. 1605 from NOAA/Pacific Marine Environmental Laboratory

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

For sale by the National Technical Information Service, 5285 Port Royal
Road

Springfield, VA 22161

REMOTE ACCESS TO DATA LISTED IN THIS REPORT

The data presented in this report is available on a computerized Remote
Bulletin Board System (RBBS), Internet FTP and the World Wide Web (WWW).
For information regarding electronic access to the data sets contact:

Mr. James C. Hendee

Data Manager, OACES

at: U.S. Dept. of Commerce

NOAA/AOML/OCD

4301 Rickenbacker Cswy.

Miami, FL 33149-1026

Telephone: 305-361-4396

Internet address: hendee@aoml.erl.gov

WWW address: http://diatom.aoml.erl.gov/oaces/oaces.html

Contoured sections of the data are also available at
http://www.pmel.noaa.gov/co2/eqpac.html.

LIST OF PARTICIPANTS

Chief Scientists: Leg 3 Richard A. Feely and Linda Mangum

Leg 4 Rik Wanninkhof and Linda Mangum

Leg 5 Paulette P. Murphy

CTD/Salinity/Dissolved Oxygen:

Leg 3 Gregg Thomas

Survey Dept. of NOAA Ship *Discoverer*

Leg 4 Gregg Thomas

Bob Roddy

Survey Dept. of NOAA Ship *Discoverer*

Leg 5 Gregg Thomas

Bob Roddy

Survey Dept. of NOAA Ship *Discoverer*

Nutrient Analyses: Leg 3 George Berberian

Lloyd Moore

Leg 4 George Berberian

Lloyd Moore

Leg 5 George Berberian

Lloyd Moore

Denis Frazel

fCO~2~ Analyses: Leg 3 Tom Lantry

Cathy Cosca

Leg 4 Hua Chen

Matt Steckley

Leg 5 Hua Chen

Matt Steckley

DIC Analyses: Leg 3 Marilyn Lamb-Roberts

David Jones

Leg 4 Tom Lantry

David Jones

Leg 5 Brian Kerns

Tom Lantry

TAlk Analyses: Leg 3 Doug Campbell

Sonia Olivella

Shannon Cass

Leg 4 Jia-Zhong Zhang

David Purkerson

Leg 5 Kitack Lee

Sanjay Mane

Jennifer Aicher

pH Analyses: Leg 3 Robert Byrne

Tonya Clayton

Beckey Li

Leg 4 No participation

Leg 5 Robert Byrne

Tonya Clayton

TOC Sampling: Leg 3 Nancy Hayward

Leg 4 Leslie Redmond

Leg 5 Gregg Ravizza

Computer Support: Jim Hendee

Betty Huss

Kristy McTaggart

Cathy Cosca

Sonia Hamilton

Dana Greeley

ET Support: Mike Shoemaker

CONTENTS

PAGE

ABSTRACT 1

1.0 INTRODUCTION 1

1.1 Cruise Itinerary 2

2.0 SAMPLING AND ANALYTICAL METHODS 2

2.1 CTD and Hydrographic Operations 2

2.2 Dissolved Oxygen (DO) 7

2.2.1 DO data quality control assessment 8

2.3 Discrete fugacity of CO~2~ (fCO~2~) 8

2.4 Dissolved Inorganic Carbon (DIC) 10

2.5 pH 12

2.6 Total Alkalinity (TAlk) 13

2.7 Nutrients 14

2.7.1 Nitrite and nitrate 14

2.7.2 Phosphate 15

2.7.3 Silicate 15

2.8 Total Organic Carbon (TOC) 15

2.9 Salinity 17

3.0 DATA TABLES 17

4.0 ACKNOWLEDGMENTS 18

5.0 REFERENCES 18

APPENDIX A C Tabulated Discrete Bottle Data 21

APPENDIX B C Dissolved Oxygen Duplicates 161

FIGURE

1\. Station locations for the boreal autumn 1992 NOAA Equatorial Pacific

> Process Study 3

TABLES

1\. Station locations and dates of the boreal autumn EqPac 1992 cruise 4

2\. Coefficients of least squares fit of CTD and bottle salinities

> during Legs 3, 4, and 5 of the boreal autumn EqPac 1992 cruise 7

3\. Precision of discrete fCO~2~ samples taken during Legs 3, 4 and 5

> of the boreal autumn EqPac 1992 9

4\. Certified reference material (Batch 12) analyzed during the boreal

> autumn EqPac 1992 cruise 12

5\. Corrections applied to DIC data during the boreal autumn EqPac 1992
cruise 12

6\. WOCE data quality flag definitions 17

7\. Unique quality control flag definitions for fCO~2~ 17

**Chemical and Hydrographic Measurements from the**

**Equatorial Pacific during Boreal Autumn, 1992**

M. F. Lamb[^1], T. Lantry^2^, J. Hendee^2^, K.E. McTaggart^1^, P.P.
Murphy^1^, R.A. Feely^1^,

R. Wanninkhof^2^, F.J. Millero^3^, R.H. Byrne^4^, E.T. Peltzer^5^, and
Denis Frazel^2^

> ABSTRACT. In the boreal autumn of 1992, NOAA=s Climate and Global
> Change Program sponsored a major cooperative effort with the U.S.
> JGOFS Program in the central and eastern equatorial Pacific to
> investigate the unique role of equatorial processes on CO~2~ cycling
> during, and following, the 1991B92 ENSO event. Data were collected
> meridionally along four transects, generally between 10N and 10S.
> The first leg (Leg 3) included the 140W and 125W transects; the
> second leg (Leg 4) sampled along 110W, and the third leg (Leg 5)
> included stations along 95W and three short transects extending
> westward from the Peru coast. Chemical parameters sampled included
> fCO~2~, DIC, TAlk, pH, TOC, and nutrients. Ancillary measurements of
> salinity, temperature, and dissolved oxygen (DO) were also taken.
> Descriptions of sampling methods and data summaries are given in this
> report.

**1.0 INTRODUCTION**

Human activity is rapidly changing the trace gas composition of the
earth=s atmosphere, causing the greenhouse warming effect from excess
carbon dioxide (CO~2~) along with other trace gas species such as
chlorofluorocarbons, methane, and nitrous oxide. These gases play a
critical role in controlling the earth=s climate because they increase
the infrared opacity of the atmosphere, causing the planetary surface to
warm. Of all the anthropogenic CO~2~ that has ever been produced, only
about half remains in the atmosphere; it is the Amissing@ CO~2~ for
which the global ocean is considered to be the dominant sink for the
man-made increase.

The equatorial region of the Pacific Ocean (EqPac) is unique because of
the huge tongue of cool surface water which is characterized by high
concentrations of nutrients and CO~2~. Our goal was to investigate the
role of equatorial processes on CO~2~ cycling during and following the
1991B92 El Niño-Southern Oscillation (ENSO) event, and to better
understand the rate at which CO~2~ is released by the oceans.

The National Oceanic and Atmospheric Administration=s (NOAA)
Ocean-Atmosphere Carbon Exchange Study (OACES) Program, in cooperation
with the U.S. Joint Global Ocean Flux Study (U.S. JGOFS) Program, the
Equatorial Pacific Ocean Climate Study (EPOCS) and Tropical Ocean Global
Atmosphere (TOGA) Program, participated in a multifaceted oceanographic
research cruise

conducted aboard the NOAA Ship *Discoverer* from September 6 to December
8, 1992. The primary objective of this U.S. JGOFS/OACES effort was to
determine the relative effects of biological fixation of carbon within
equatorial upwelling, followed by vertical flux of that fixed carbon to
abyssal depths, and of CO~2~ outgassing. The cruise was focused on
determining the concentrations of carbon species and describing ocean
circulation in the upper ocean over the equatorial Pacific from 95W to
140W. This data report summarizes the carbon species, nutrients,
dissolved oxygens, total organic carbon, and salinities from this
cruise. The tabulated discrete bottle data are given in Appendix A.

**1.1 Cruise Itinerary**

The ship departed Hilo, Hawaii on Sept. 6, 1992 and proceeded to the
first station at 10N and 140W. A test cast was performed during the
transit to check equipment. The cruise track for the first leg (Leg 3)
of the cruise started at 10N, 140W and proceeded south along the
longitudinal line to 10S; the ship then transited to 10S, 125W, and
sampled north along that meridional line to 10N; Leg 3 ended in
Manzanillo, Mexico.

The second leg (Leg 4) departed Manzanillo, Mexico on Oct. 12, 1992 and
began operations at 10N, 110W. Problems with the electrical generator
forced a diversion to San Diego for repairs. Research was resumed at 8N
on Oct. 31, and stations were sampled along 110W longitude to 10S;
additionally, stations were sampled between 2S and 2N along 95W. The
ship ended Leg 4 in Salinas, Ecuador on Nov. 18, 1992.

The third leg (Leg 5) departed Salinas, Ecuador on Nov. 19, 1992 and
occupied stations off the coast of Peru along 5S from 8120W to 8230W. An
additional line of stations was completed between 1251S, 7830W to 1220S,
7720W, and then between 33S, 8121 to 95W, 14S where stations were
occupied along the meridional line to 3N, where a medical evacuation
forced cessation of the sampling. The cruise ended in San Diego on Dec.
8, 1992. Station locations and dates are contained in Figure 1 and Table
1.

**2.0 SAMPLING AND ANALYTICAL METHODS**

**2.1 CTD and Hydrographic Operations**

AOML=s Neil BrownJ Instrument Systems (NBIS) Mark IIIb CTD #4 and
General Oceanics 24-bottle rosette were used to measure pressure,
temperature, and conductivity for all casts through station 67 on Leg 4.
After station 67, AOML=s NBIS Mark IIIb CTD #1 and General Oceanics
12-bottle rosette were employed and two casts were completed at each
station in order to similarly sample the water column. CTD data were
recorded during the downcast and the upcast, and discrete water samples
were collected in 10-L NiskinJ bottles during the upcast. CTD data
passed through an NBIS 1150 deck unit were acquired using AOML CTD
acquisition software. A personal computer displayed real-time profiles
and wrote the data to hard disk. An audio backup was made to VHS tape.
Data files were archived on 5.25\" removable hard disk cartridges.

Pre-cruise calibrated, 1-db averaged data files were calibrated and
processed at PMEL (McTaggart *et al.,* 1994). To correct for
cast-dependent drifts, coefficients of a least squares fit of CTD
salinities and bottle salinities to a first order polynomial were
computed for groups of stations

Table 1. Station locations and dates of the boreal autumn EqPac 1992
cruise.

Station Cast Latitude Longitude Date

***Leg 3:***

1(test cast) 4 16 29.79N 149 53.57W 7-Sep-92

2 10 10 0.38N 139 59.45W 10-Sep-92

3 12 8 57.67N 140 18.19W 10-Sep-92

4 17 7 59.98N 139 59.95W 11-Sep-92

5 19 6 0.28N 139 59.97W 11-Sep-92

6 21 5 0.39N 140 3.33W 11-Sep-92

6 26 5 0.2N 140 3.41W 12-Sep-92

7 28 3 58.3N 140 0.39W 12-Sep-92

8 32 2 59.35N 140 7.21W 12-Sep-92

9 34 1 9.64N 140 0.31W 13-Sep-92

10 36 1 0.01N 139 59.83W 13-Sep-92

11 37 0 29.67N 140 0.13W 13-Sep-92

12 41 0 0.16N 140 0.04W 14-Sep-92

13 42 0 15.04N 139 59.37W 14-Sep-92

14 43 0 15.0S 139 59.76W 14-Sep-92

15 48 0 29.73S 139 59.92W 15-Sep-92

16 50 0 59.41S 139 59.92W 15-Sep-92

17 54 2 0.56S 140 0.92W 16-Sep-92

18 56 2 59.88S 140 0.1W 16-Sep-92

19 58 3 59.62S 140 0.15W 16-Sep-92

20 63 4 58.36S 140 1.43W 17-Sep-92

21 66 6 0.13S 140 0.07W 17-Sep-92

22 70 7 0.04S 140 0.16W 17-Sep-92

23 77 10 0.09S 135 0.43W 19-Sep-92

24 81 10 0.05S 125 0.03W 20-Sep-92

25 89 7 57.6S 125 1.69W 22-Sep-92

26 91 5 59.81S 125 0.13W 22-Sep-92

27 94 4 59.99S 125 0.09W 23-Sep-92

28 101 4 0.11S 125 0.0W 23-Sep-92

29 106 3 0.0S 125 0.12W 24-Sep-92

30 108 1 59.98S 125 0.03W 24-Sep-92

31 115 0 59.9S 124 59.33W 25-Sep-92

32 118 0 29.88S 124 59.66W 25-Sep-92

33 119 0 14.93S 124 59.53W 26-Sep-92

34 122 0 1.35N 124 52.66W 26-Sep-92

35 126 0 15.33N 124 59.34W 27-Sep-92

36 127 0 30.79N 124 59.98W 27-Sep-92

37 129 1 1.47N 124 59.48W 27-Sep-92

38 134 1 59.95N 125 0.13W 28-Sep-92

39 144 2 59.86N 125 0.26W 28-Sep-92

40 146 4 0.09N 125 0.06W 29-Sep-92

41 153 5 3.12N 125 0.9W 30-Sep-92

42 156 6 0.07N 124 59.9W 30-Sep-92

43 157 6 59.85N 124 59.46W 30-Sep-92

44 159 8 3.45N 124 59.77W 1-Oct-92

45 163 8 59.82N 124 59.91W 1-Oct-92

46 169 9 59.28N 124 59.36W 2-Oct-92

47 174 11 59.37N 125 0.44W 2-Oct-92

48 175 13 42.92N 120 0.09W 3-Oct-92

Table 1. (continued)

Station Cast Latitude Longitude Date

***Leg 4:***

50 182 10 1.08N 109 56.85W 17-Oct-92

51 187 8 0.03N 110 0.09W 31-Oct-92

52 195 5 59.78N 109 59.8W 1-Nov-92

53 201 4 58.14N 109 54.98W 1-Nov-92

54 208 3 59.02N 109 59.79W 2-Nov-92

55 209 2 59.85N 110 0.56W 2-Nov-92

56 211 2 6.75N 110 6.8W 2-Nov-92

57 218 0 59.69N 110 0.71W 3-Nov-92

58 223 0 31.14N 110 0.15W 3-Nov-92

59 224 0 15.26N 109 59.98W 4-Nov-92

60 229 0 11.64N 110 5.3W 4-Nov-92

61 234 0 0.79N 110 0.38W 4-Nov-92

62 235 0 15.19S 110 0.12W 5-Nov-92

63 236 0 30.9S 110 0.36W 5-Nov-92

64 237 1 0.0S 109 59.97W 6-Nov-92

65 244 2 5.6S 109 54.1W 6-Nov-92

66 247 2 59.51S 110 1.11W 7-Nov-92

67 253 3 59.97S 109 58.35W 8-Nov-92

67 254 4 0.04S 109 58.54W 8-Nov-92

68 255 4 59.86S 110 2.13W 8-Nov-92

68 258 4 59.95S 110 1.72W 8-Nov-92

69 264 6 0.01S 110 0.01W 8-Nov-92

69 266 5 59.9S 110 0.04W 9-Nov-92

70 267 8 0.05S 109 59.96W 9-Nov-92

70 270 7 59.68S 110 0.16W 9-Nov-92

71 276 10 0.03S 110 0.11W 10-Nov-92

71 278 9 59.91S 109 59.94W 10-Nov-92

72 287 2 0.0S 95 0.0W 13-Nov-92

73 291 0 0.86S 95 3.34W 14-Nov-92

74 296 1 57.28N 94 9.05W 15-Nov-92

***Leg 5:***

75 302 5 0.0S 81 20.02W 20-Nov-92

76 303 4 59.95S 81 30.04W 20-Nov-92

76 306 5 0.1S 81 29.88W 21-Nov-92

77 307 5 0.03S 81 40.08W 21-Nov-92

77 308 5 0.06S 81 40.0W 21-Nov-92

78 309 5 0.01S 81 50.01W 21-Nov-92

78 311 5 0.07S 81 50.09W 21-Nov-92

79 312 5 0.02S 81 59.99W 21-Nov-92

79 313 4 59.98S 82 0.05W 21-Nov-92

80 314 5 0.02S 82 30.12W 21-Nov-92

80 318 4 59.95S 82 29.88W 21-Nov-92

81 319 12 51.0S 78 36.92W 23-Nov-92

81 321 12 51.0S 78 37.02W 23-Nov-92

82 322 12 45.24S 78 21.29W 23-Nov-92

82 323 12 44.93S 78 21.03W 23-Nov-92

83 324 12 39.02S 78 5.9W 23-Nov-92

83 327 12 38.94S 78 5.83W 23-Nov-92

84 328 12 32.0S 77 48.99W 23-Nov-92

Table 1. (continued)

Station Cast Latitude Longitude Date

***Leg 5 (cont.):***

84 332 12 32.14S 77 49.0W 23-Nov-92

85 333 12 26.81S 77 35.51W 23-Nov-92

85 337 12 26.84S 77 35.6W 23-Nov-92

86 338 12 19.98S 77 19.86W 24-Nov-92

87 340 13 2.58S 81 20.74W 24-Nov-92

87 344 13 2.54S 81 20.81W 24-Nov-92

88 345 13 0.14S 84 4.6W 25-Nov-92

88 347 13 13.98S 84 4.48W 25-Nov-92

89 348 13 25.6S 86 48.3W 25-Nov-92

89 352 13 25.47S 86 8.5W 25-Nov-92

90 353 13 32.34S 88 29.81W 26-Nov-92

91 354 13 36.92S 89 32.24W 26-Nov-92

91 356 13 36.96S 89 2.18W 26-Nov-92

92 357 13 48.61S 92 15.71W 26-Nov-92

92 361 13 48.65S 92 15.98W 26-Nov-92

93 362 14 0.05S 94 59.9W 27-Nov-92

93 364 14 0.01S 94 59.98W 27-Nov-92

95 366 11 55.08S 94 59.97W 27-Nov-92

95 369 11 55.09S 95 0.0W 28-Nov-92

96 370 10 0.24S 94 59.89W 28-Nov-92

96 372 9 59.99S 95 0.0W 28-Nov-92

97 373 8 0.05S 95 0.09W 28-Nov-92

97 377 8 0.1S 95 59.75W 28-Nov-92

98 378 6 0.1S 95 0.37W 29-Nov-92

98 380 5 59.98S 94 59.96W 29-Nov-92

99 381 5 0.0S 95 0.1W 29-Nov-92

99 383 5 0.03S 95 0.06W 29-Nov-92

100 388 4 0.2S 95 0.14W 29-Nov-92

100 390 4 0.09S 95 0.14W 30-Nov-92

101 391 4 0.09S 95 0.14W 30-Nov-92

101 393 3 0.18S 94 59.97W 30-Nov-92

102 395 1 59.95S 95 0.13W 30-Nov-92

102 399 1 59.92S 95 0.17W 30-Nov-92

103 401 1 0.16S 94 59.92W 30-Nov-92

103 403 1 0.21S 94 59.57W 30-Nov-92

104 405 0 0.01N 95 0.18W 1-Dec-92

105 410 1 0.08N 95 0.2W 1-Dec-92

105 414 0 59.95N 95 0.39W 1-Dec-92

106 416 1 59.94N 95 0.31W 1-Dec-92

106 418 2 0.0N 94 0.2W 2-Dec-92

107 423 3 0.04N 95 0.06W 2-Dec-92

Table 2. Coefficients of least squares fit of CTD and bottle salinities
during Legs 3, 4, and 5

of the boreal autumn EqPac 1992 cruise.

Station Bias Slope Std. Dev. \# of Pts.

1B 22 B0.1592176EB01 0.1000271E+01 0.0056 396

23B 48 0.1783609EB01 0.9993343E+00 0.0067 472

49B 67 B0.1083432E+00 0.1003059E+01 0.0042 351

67 B0.2837561E+00 0.1007903E+01 0.0049 21

68B 74 0.9982839EB01 0.9972650E+00 0.0029 71

75B107 0.3461486EB01 0.9990724E+00 0.0023 634

and applied to CTD salinities (Table 2). No additional calibrations were
applied to pressure or temperature.

Samples were collected from 10-L PVC NiskinJ bottles in the following
order: dissolved oxygen (DO), discrete fugacity of CO~2~ (fCO~2~),
dissolved inorganic carbon (DIC), pH, total alkalinity (TAlk), C-13/C-12
isotope ratios, nutrients, total organic carbon (TOC), particulate
organic carbon (POC), particulate organic nitrogen (PON), and
salinities. In addition, underway surface fCO~2~ samples were collected
on a continuous basis throughout the cruise. This report does not
address C-13/C-12, POC, PON or underway fCO~2~ measurements.

**2.2 Dissolved Oxygen (DO)**

DO samples were the first to be collected from 10-L NiskinJ bottles once
the CTD unit was retrieved on deck. Samples were collected in
volume-calibrated 150-mL, clear, ground-glass stoppered sample bottles
using TygonJ tubing; the drawing tube was outfitted with a latex
attachment to prevent the TygonJ tubing from coming into contact with
the stopcock nipple and causing TOC contamination. The sample bottles
were rinsed twice and filled from the bottom to minimize bubble
entrainment, and overflowed approximately half a volume. 1-mL manganous
chloride (600 g MnCl~2~-4H~2~O in 1 L H~2~O) and 1-mL alkaline sodium
iodide (320 g NaOH and 600 g NaI in 1 L H~2~O) were added to the sample
bottles. The top depressions of the bottles were filled with fresh water
to prevent intrusion of air, and samples were kept in darkness until
analysis.

DO samples were titrated following the technique of Carpenter (1965) and
Friederich *et al.* (1984). A computer-controlled automatic pipette was
used for titration with photometric endpoint determination. Values are
marked as questionable in the data tables when there were high or low
photometric endpoints in the titration process due to improper light
levels, or there was possible contamination during processing (air
bubbles seen in bottle, etc.). The data are reported in the data tables
(Appendix A) in μmol/L, but are available in the data base in both
μmol/L, and μmol/kg. The density conversion was made using in-situ
temperatures and measured salinity.

*2.2.1 DO data quality control assessment*

The most useful quality control checks with other data sets would
compare deep water values. However, the maximum depth of the casts was
1000 db, and variability in DO values cannot be excluded at 1000 db. The
quality of the data was evaluated by examining profiles, contour maps,
replicates, property/property plots, and comparisons with other data
sets.

For nearly every cast on these cruises, a second NiskinJ was tripped at
the maximal depth. This gave a large set of duplicate samples which was
used to assess the combined precision of the analytical technique, the
NiskinJ subsampling technique, and ocean subsampling by the NiskinJ
(Appendix B). Precision is here defined as the average of the relative
error between the samples and it is expressed in percent. The relative
error is expressed as the absolute difference divided by the mean for
two samples or standard deviation divided by the mean for more than two
samples.

For Leg 3 the double-trip duplicates were all sampled from 1000 db (41
pairs). The mean difference of duplicate results was 0.40% with 1.22%
standard deviation if one pair (Station 45 at 9N, 125W) was excluded.
These statistics are consistent with the statistics for a set of NiskinJ
subsampling duplicates taken from 13 different NiskinJ bottles on one
cast on Leg 3 (Station 12 at 0, 140W) which gave a standard deviation
from the mean of 1.14%. On Leg 4, 20 duplicates plus one triplicate were
sampled from NiskinsJ tripped at 1000 db. The mean difference was 0.29%
with 1.08% standard deviation. For Leg 5, 29 pairs of duplicates were
sampled from NiskinsJ tripped at 800 db. The mean difference was 1.65%
with 3.92% standard deviation. The overall mean difference for all three
legs was 0.78% difference between duplicates with 2.42% standard
deviation if one pair (Station 45 at 9N, 125W) was excluded.

**2.3 Discrete fugacity of CO~2~ (fCO~2~)**

Samples were drawn from 10-L NiskinJ bottles into 500-mL PyrexJ
volumetric flasks using TygonJ tubing outfitted with a latex attachment
to prevent the TygonJ tubing from coming into contact with the stopcock
nipple. Bottles were rinsed once, and while taking care not to entrain
air bubbles, were filled from the bottom until half the bottles= volume
overflowed. Five mL of water was then withdrawn with a pipette to create
a small expansion volume. A saturated HgCl~2~ solution (0.2 mL) was
added to the samples as a preservative. The sample bottles were then
sealed with a screw cap containing a polyethylene liner and stored in
darkness at room temperature for a maximum of 24 hours prior to
analysis.

The AOML discrete fCO~2~ system is patterned after the design described
in Chipman *et al*. (1993) and is discussed in detail in Wanninkhof and
Thoning (1993). The major difference between the two systems is that the
AOML system uses a LicorJ (model 6262) non-dispersive infrared analyzer,
while the Chipman *et al*. system utilizes a gas chromatograph with a
flame ionization detector and a methanizer, which quantitatively
converts CO~2~ into CH~4~ for analysis.

The samples were brought to a temperature of 20.00  0.02C, using a
pre-bath at 19B21C and a NeslabJ (model RT-220) controlled temperature
bath. In the analyses, two samples are analyzed concurrently; a 60-mL
headspace is created in the flasks by replacing the water using a
compressed standard gas with a CO~2~ mixing ratio close to the
anticipated fCO~2~ of the water. The headspace is circulated in a closed
loop through the infrared analyzer (IR), which measures CO~2~ and water
vapor levels in the sample cell. The headspaces of the two flasks are
equilibrated simultaneously in channels A and B. While headspace from
the flask in channel A goes through the IR analyzer, the headspace of
the flask in channel B is recirculated in a closed loop. The sample in
the A channel is equilibrated for 17 minutes while the air from the
headspace of the flask flows through the IR analyzer. The sample in the
B channel is circulated in a closed loop for 10 minutes and through the
IR for 8 minutes. An expandable volume, consisting of a balloon, keeps
the contents of the flasks at room pressure.

In order to maintain measurement accuracy and precision, a set of six
gas standards was run through the system after every four to ten
seawater samples. The standards have mixing ratios of 201.4, 352.2,
511.7, 1012.2, 1552.8, and 2019.8 ppm, which bracket the fCO~2~ at 20C
(fCO~2~, 20) values observed in the water column of the equatorial
Pacific. The commercial CO~2~ standards (supplied by ScottJ and Air
ProductsJ) in Aartificial air@ were calibrated against WMO (World
Meteorological Organization) standards in real air supplied by Dr.
Charles Keeling of Scripps Institution of Oceanography (SIO) with mixing
ratios of 204.0, 350.4, 795.0, and 1504 ppm.

The determination of fCO~2~ in water from the discrete analyses involves
several steps. The mixing ratio and detector response for the standards
were normalized for temperature and pressure. The IR voltage output for
samples were normalized with regard to pressure and were corrected for
the presence of water vapor and converted to a mixing ratio. The mixing
ratio in the headspace was converted to fugacity and corrected to
fugacity of CO~2~ in the water sample prior to equilibration by
accounting for change in DIC in water during the equilibration process
(for details see Wanninkhof and Thoning, 1993). The change in the fCO~2~
of water, (fCO~2w~), caused by the change in DIC, was calculated using
the constraint that TAlk remains constant during exchange of CO~2~ gas
between the headspace and the water. The calculation is outlined in the
appendix of Peng *et al*. (1987).

Precision of the fCO~2~ analyses shown in Table 3 were determined in
four different ways: from re-analyses of the same water sample; from
agreement between surface mixed layer values (where mixed layer is
defined as the depth of the surface layer with temperatures within
0.5^o^C); from duplicates of samples taken from the same NiskinJ bottle;
and duplicates taken from the same depth but from different NiskinJ
bottles. The precision is defined as the average of the relative

Table 3. Precision of discrete fCO~2~ samples taken during Legs 3, 4 and
5 of the boreal autumn EqPac 1992.

Leg 3 Leg 4 Leg 5

precision \# of precision \# of precision \# of

\% replicates % replicates % replicates

Re-analysis 0.42 35 0.12 31 0.17 50

Same depth 1.10 36 0.38 23 0.36 34

Mixed layer 3.21 39 0.77 21 1.45 26

Same NiskinJ 0.99 2 N/A N/A

error between the samples and is expressed in percent. The percent
relative error is expressed as the absolute difference divided by the
mean for two samples, or standard deviation divided by the mean for more
than two samples.

**2.4 Dissolved Inorganic Carbon (DIC)**

Samples were drawn from 10-L NiskinJ bottles into 500-mL PyrexJ bottles
using TygonJ tubing outfitted with a latex attachment to prevent the
TygonJ tubing from coming into contact with the stopcock nipple. Bottles
were rinsed once and filled from the bottom, overflowing half a volume
while taking care not to entrain any bubbles. The tube was pinched off
and withdrawn, creating a 5-mL headspace volume. 0.2 mL of saturated
HgCl~2~ solution was added as a preservative. The sample bottles were
sealed with glass stoppers lightly covered with Apiezon-LJ grease, and
were stored at room temperature in the dark for a maximum of 24 hours
prior to analysis by coulometeric determination.

DIC was analyzed by coulometry, and two analytical set-ups were used
simultaneously on the cruise, each consisting of a coulometer (UIC,
Inc.) coupled with a SOMMA (Single Operator Multiparameter Metabolic
Analyzer) inlet system developed by Ken Johnson (Johnson, 1992; Johnson
*et al.*, 1993) of Brookhaven National Laboratory (BNL). AOML-1 was
supplied by the group from NOAA/AOML, and PMEL-1 was provided by the
group from NOAA/PMEL.

In the coulometric analysis of DIC, all carbonate species (CO~3~^2B^ and
HCO~3~^B^) are converted to CO~2~ (gas) by addition of excess H^+^ to
seawater, and includes the following steps: the 500-mL sample bottle is
inserted in a water bath at 20C and allowed to come to thermal
equilibrium; water from the bottle is displaced by presurization into a
calibrated, thermostatted pipette using a headspace gas (511 ppm CO~2~
in N~2~) . Using Ultra-Pure N~2~ as the carrier gas, the sample is
injected into the reaction vessel in the SOMMA which contains 1-mL 10%
H~3~PO~4~ solution previously stripped of CO~2~, and the evolved CO~2~
gas from the sample is carried through a condenser and a Mg(ClO~4~)~2~
column to dry the gas stream, and then through an ORBO-53J tube to
remove volatile acids other than CO~2~ . In the titration cell of the
coulometer, CO~2~ reacts quantitatively with ethanolamine to form
hydroxyethyl carbamic acid which is titrated with OH^B^ ions
electrogenerated by the reduction of H~2~O at a platinum cathode. The
equivalence point is detected photometrically with thymolphthalein as
indicator. The cell solution is blue at the equivalence point of 10.5 pH
and colorless at pH 9.3 after the addition of CO~2~ in aqueous solutions
(Johnson *et al.*, 1985). CO~2~ drives down the pH and raises %
transmittance. As the acid is titrated, pH increases (hence, the blue
color returns) and % transmittance decreases, thus causing the titration
current to decrease as the equivalence point is approached and sensed by
the optical detector. Therefore, the CO~2~ is measured by the quantity
of electrons required to reach the equivalence point, calculated by the
magnitude of the current and the time of passage.

The coulometers were each calibrated by injecting aliquots of pure CO~2~
(99.995%) by means of an 8-port valve outfitted with two sample loops.
The loop volumes were calibrated at BNL (Wilke, 1993) prior to, and
following, the cruise, and no significant difference was found between
the pre- and post-cruise calibrations. All DIC values were corrected for
dilution by 0.2 mL of HgCl~2~ solution assuming the solution was
saturated with atmospheric CO~2~ levels and total water volume was 540
mL. The correction factor used was 1.00037. No correction was made for
headspace gas exchange with the sample due to the probable variability
of fCO~2~ at the location of sampling, and the small magnitude (\<1.0
μmol/kg) of the correction. The overall accuracy and precision for both
the AOML and PMEL instruments combined was determined to be within 1.8
μmol/kg.

The instruments were calibrated at the beginning, middle and end of each
coulometer cell solution with a set of the gas loop injections.
Calculation of the amount of CO~2~ injected was according to the DOE
Handbook of Methods for the Analysis of the Various Parameters of the
Carbon Dioxide System in Sea Water, Ver. 2 (1994). The set of gas loops
yielded a mean calibration factor (CF) for the instrument defined as:

The concentration of DIC in the samples was determined according to:

where ACounts@ is the instrument reading at the end of the analysis,
ABlank@ is the counts/minute determined from blank runs performed at
least once for each cell solution, ARun Time@ is the length of
coulometric titration (in minutes), A2.0728  10^B4^@ is the conversion
factor from counts to μmol.

The pipette volume was determined by taking aliquots at known
temperature of distilled water dispensed from the pipette before,
during, and after the cruise and weighing them ashore. No significant
volume change was observed for either instrument. The weights with the
appropriate densities were used to determine the volume of the pipette.
Calculation of pipette volumes, density, and final CO~2~ concentration
were performed according to procedures outlined in the DOE Handbook
(1994).

A Certified Reference Material (CRM) consisting of seawater poisoned
with HgCl~2~ (Batch 12) prepared by Dr. Andrew Dickson (SIO) was
analyzed on both instruments over the duration of the cruise (Table 4).
The absolute value was determined by the manometric technique of Dr.
Charles Keeling, also of SIO. All DIC data have been corrected to the
CRM values on a per instrument/per leg basis; the corrections applied
are given in Table 5.

The precision of the DIC measurements was determined in three different
ways: analyses of six NiksinJ bottles all tripped at \~1000 db at
Station 1 (test cast) yielded at standard deviation of 1.7  μmol/kg;
CRM=s (Table 4) analyzed during the cruise show that the standard
deviation at the 1σ level were within 1.9 μmol/kg (n = 138); duplicate
pairs tripped at the maximal depth throughout the cruise show a mean
difference of 0.1  2.1 μmol/kg (n = 93).

Table 4. Certified reference material (Batch 12) analyzed during the
boreal autumn EqPac 1992.

PMEL-1 AOML-1

μmol/kg μmol/kg

Leg 3: 1984.1  1.8, n = 37 1985.6  0.8, n = 21

Leg 4: 1986.0  1.9, n = 20 1985.1  1.2, n = 22

Leg 5: 1983.9  0.9, n = 19 1986.3  0.3, n = 19

> Manometrically derived DIC = 1984.26  0.73 μmol/kg (n = 7). Standard
>
> deviations are given at the 1σ level.

Table 5. Corrections applied to DIC data during the boreal autumn EqPac
1992 cruise.

PMEL-1 AOML-1

μmol/kg μmol/kg

Leg 3: +0.2 B1.3

Leg 4: B1.7 B0.9

Leg 5: +0.4 B2.0

**2.5 pH**

Sample cells (10-cm pathlength spectrophotometric cells, 30-cm^3^
volume) were filled directly from the NiskinJbottle using a 20-cm length
of TygonJ tubing outfitted with a latex attachment to prevent the TygonJ
from coming into contact with the stopcock nipple; a flushing volume of
approximately 300 mL was used. Care was taken to eliminate bubbles from
the sampling system, and the sample cell was sealed with PTFE caps while
ensuring that there was no head space.

All spectrophotometric pH measurements were made using the indicator
m-Cresol Purple. Spectrophotometric cells were warmed to 25C in a
twelve-chambered thermostated aluminum block and subsequently cleaned
and placed in the thermostated sample compartment of the
spectrophotometer. Absorbance measurements were made at three
wavelengths: a non-absorbing wavelength (730 nm) and wavelengths
corresponding to the absorbance maxima of the alkaline (I^2B^, 578 nm)
and acidic (HI^B^, 434 nm) forms of the indicator. Subsequently, one of
the cell caps was removed and 0.08 cm^3^ of concentrated indicator (2
μmol/cm^3^) was injected into the cell. The cell was capped, rapidly
mixed and returned to the thermostated cell. Absorbance measurements
were again made at 730 nm, 578 nm and 434 nm. Sample pH was then
calculated using the equations and procedures of Clayton and Byrne
(1993). The Atotal@ pH scale is used, and pH~T~ is reported in mol/kg of
seawater.

**2.6 Total Alkalinity (TAlk)**

Samples were drawn from 10-L NiskinJ bottles into 500-mL PyrexJ bottles
using TygonJ tubing outfitted with a latex attachment to prevent the
TygonJ tubing from coming into contact with the stopcock nipple. Bottles
were rinsed once and filled from the bottom, overflowing half a volume
while taking care not to entrain any bubbles. The tube was pinched off
and withdrawn, creating a 5-mL headspace volume. The sample bottles were
sealed with glass stoppers, and were stored at room temperature in the
dark for a maximum of 6 hours prior to analysis by potentiometric
determination.

The TAlk titration system was similar to the one used in previous
studies (Thurmond and Millero, 1982; Bradshaw and Brewer, 1988) and
consisted of a Metrohm 665 DosimatJ titrator and an Orion 720A pH meter
operated by a personal computer. Both the acid titrant and the seawater
sample were maintained at 25C with a NeslabJ temperature bath. The
plastic jacketed cells (volume \~200 cm^3^) were patterned after an
earlier design of Bradshaw and Brewer (1988) except a larger volume was
used to increase the precision. The cell had zero dead volume valves to
increase the reproducibility of the cell volume. A GW-BasicJ program was
used to control the titrant addition and read the emf of the electrodes.
The titration was made by adding HCl to seawater past the carbonic acid
end point. A typical titration records the emf reading after it becomes
stable (0.09 mV) and adds enough acid to change the voltage by a
pre-assigned increment (13 mV). The electrodes used to measure emf
consisted of a ROSSJ glass pH electrode and an OrionJ double junction
Ag/AgCl reference electrode.

The HCl acid solutions (20 L) were made, standardized, and stored in
500-mL glass bottles prior to the cruise. The 0.25 M HCl solutions were
made with 1 M MallinckrodtJ standard solutions in 0.45 M NaCl to yield
an ionic strength equivalent to that of average seawater (0.7 M). The
acid was standardized by titrating weighed amounts of Na~2~CO~3~ and
TRIS dissolved in 0.7 M NaCl solutions. The blanks in the 0.7 M NaCl
solutions were determined by coulometry and by titrations of the NaCl
solutions with and without added Na~2~CO~3~ and TRIS. The blanks of the
titrations of TRIS were determined by extrapolation to zero added salt
(Goyet and Hacker, 1992).

The alkalinity blanks in the NaCl were approximately 14  1 μmol. Cell
volumes were determined in the laboratory by weighing the cells filled
with degassed Millipore water. The density of water at the temperature
of the measurements (25C) was calculated from the international equation
of state of seawater (Millero and Poisson, 1981). The nominal volumes of
all the cells were about 200 cm^3^ and the values were determined to
0.03 cm^3^.

The NaCl, Na~2~CO~3~ and NaHCO~3~ salts used to make up the solutions
were Baker AnalyzedJ reagent grade. Details on preparation and
calibration of the seawater buffers are given in Dickson (1993) and
Millero (1993). Approximately 20 L of standard carbonate solutions in
0.7 M NaCl were prepared for the calibrations of the acids. The
solutions were equilibrated with air to provide an alkalinity and nearly
constant DIC standard. The DIC in the blanks and carbonate solutions was
measured daily using a coulometer (see Section 2.4). The coulometer was
calibrated using CO~2~ gas loops and monitored with Batch #12 CRM.

The volume of HCl delivered to the cell is traditionally assumed to have
small uncertainties (Dickson, 1981) due to the digital output of the
titrator. Calibrations with water at 25C of the Dosimats= burettes
indicate that the systems deliver 3 cm^3^, a typical value for a
titration of seawater, to a precision of 0.0004 cm^3^. This uncertainty
results in an error of 0.4 μmol kg^B1^ in TAlk. The accuracy of the
volume of acid delivered by the Dosimats, however, was ten times poorer
(0.004 cm^3^) than the precision. Since the titration systems were
calibrated using standard solutions, this error in accuracy of volume
delivery will be partially cancelled and included in the value assigned
to the concentration of HCl and the volume of the cell.

**2.7 Nutrients**

Nutrient samples were collected from 10-L NiskinJ bottles in aged 60-mL
linear polyethylene bottles after three complete seawater rinses, and
stored in the dark at 4C until analysis was completed (within 24 hours
of sample collection). Concentrations of dissolved nitrite (NO~2~^B^),
dissolved nitrate (NO~3~^B^), dissolved phosphate (HPO~4~^2B^) and
silicate (H~4~SiO~4~) were determined using an AlpkemJ Rapid Flow
AnalyzerJ (RFA/2J) Auto-Analyzer aboard ship. The water used for the
preparation of standards, determination of blank and wash between
samples was filtered Gulf Stream seawater obtained from the surface of
the Strait of Florida. Analytical temperature was assumed to be 25  1C.
The data are reported in the data tables (Appendix A) as μmol/L, but are
available in the data base in both μmol/L and μmol/kg. The density
conversion was made using the aforementioned analytical temperature and
measured salinity.

*2.7.1 Nitrite and nitrate*

The automated colorimetric procedures and methodologies used in the
analysis of nitrite and nitrate are similar to those described by
Armstrong *et al*. (1967), with modifications described in Atlas *et
al*. (1971). Standardizations were performed prior to each sample run
with working solutions prepared aboard ship from pre-weighed Baker
AnalyzedJ reagent grade standards. Nitrite (NO~2~^B^) was determined by
diazotization with sulfanilamide and coupling with
N‑ (1‑naphthyl) ethylenediamine dihydrochloride to form an azo dye. The
color produced is proportional to the nitrite concentration. Samples for
nitrate (NO~3~^B^) analysis were passed through copperized cadmium in
the form of an Open Tubular Cadmium Reactor (OTCR) coil, which reduced
nitrate to nitrite; the resulting nitrite concentration was then
determined as described above. The detection limits for nitrite and
nitrate were 0.1 μmol/L and 0.4 μmol/L, respectively. The standard
deviation of the analyses of samples from two NiskinJ bottles at 1000 db
were used to estimate the overall precision obtained by the sampling and
analytical procedures. The percent relative error of nitrate analysis
for these samples was 0.38%  0.37% (n = 80).

*2.7.2 Phosphate*

The analytical procedures and methodologies used in the analysis of
phosphate are similar to those described by Armstrong *et al*. (1967),
with modifications described in Grasshoff *et al*. (1983). In this
method, orthophosphate in the samples was determined by reacting with
molybdenum (VI) and antimony (III) in an acidic medium to form an
antimonyphospho-molybdate complex. This complex was subsequently reduced
with ascorbic acid to form a blue complex and the absorbance was
measured at 880 nm by a filter photometer in RFA/2J system. The method
detection limit was 0.08 μmol/L. The percent relative error of phosphate
analysis for samples from two NiskinJ bottles at 1000 db was
0.92%  0.77% (n = 76).

*2.7.3 Silicate*

The analytical procedures and methodologies used in the analysis of
silicate are essentially similar to those described by Armstrong *et
al*. (1967), with modifications described in Atlas *et al*. (1971). In
this modified method, β-molybdosilicic acid was formed by reaction of
the silicate contained in the sample with molybdate in an acidic
solution. The βBmolybdosilicic acid was then reduced by stannous
chloride to form molybdenum blue. The absorbance of the molybdenum blue,
measured at 660 nm, was linearly proportional to the concentration of
silicate in the sample, with a detection limit of 0.4 μmol/L. The
percent relative error of silicate analysis for samples from two NiskinJ
bottles at 1000 db was 1.41%  1.24% (n = 72).

**2.8 Total Organic Carbon (TOC)**

All samples for total organic carbon (TOC) analysis were collected using
the 10L-NiskinJ bottles on a 12- or 24-bottle CTD-rosette. The NiskinJ
bottles used red silicone rubber o-rings and nylon coated stainless
steel springs; stopcocks were polyethylene.

A strict sample drawing order was followed. Samples for DO, fCO~2~, DIC,
and pH were drawn first using sample drawing tubes with silicone rubber
or surgical rubber connectors. At no time was TygonJ tubing used in
direct contact with the stopcock nipple prior to drawing the TOC
samples, nor was the vial allowed to come into contact with the stopcock
nipple. 30-mL samples were drawn into 40-mL PyrexJ glass vials. The
vials were rinsed prior to filling three times with sample and at no
time was the vial allowed to come into contact with the NiskinJ stopcock
nipple. Samples were tightly capped with teflon lined screw-caps and
kept under cover to prevent excessive warming while on deck.

Immediately following collection, the samples were returned to the
shipboard lab and acidified with 160 μL of 50% (w/w) H~3~PO~4~. Samples
were NOT filtered. The samples were stored at 4C until ready to be
shipped home. At that time they were wrapped as flats of 100 vials in
bubble wrap, transferred to a cooler filled with frozen Ablue@ ice, then
hand-carried to the airport and shipped home as excess baggage. All
samples were in the lab refrigerator within 48 hours of shipping.

Samples were analyzed by the high-temperature combustion/discrete
injection (HTC/DI) technique (Peltzer and Brewer, 1993) using a custom
built analyzer. Immediately prior to analysis the samples were sparged
with CO~2~-free oxygen at 500 mL/min for 6B7 minutes. Each sample was
injected in triplicate into a third-generation HTC/DI analyzer
consisting of a two-stage combustion system. The combustion tube
contained 5% Pt on alumina catalyst (Dimatec, Essen, Germany) at 800C in
the upper catalyst zone, and copper oxide and SulfixJ (Wako Chemical
Corp., Richmond, VA) at 600C in the lower zone. Oxygen was used as a
carrier gas. The gas stream passes through a AgNO~3~/H~3~PO~4~ bubbler,
a U-tube cold trap at 1B2C, a Mg(ClO~4~)~2~ drying tube and two particle
filters (0.1 μm and 0.01 μm, Balston Inc., Lexington, MA) before
entering a LiCor Model 6252 NDIR CO~2~ analyzer. The output from the
CO~2~ detector is continuously monitored and recorded using TurboChromJ
3 software operating on a 386-PC in a Windows environment. All peaks
were visually checked for proper baseline integration and appropriate
peak shape. Those not passing were either manually re-integrated or
rejected. If only one peak of the three was acceptable, the sample run
was rejected and a new run with three more injections from the same
sample was made.

Stringent quality control/quality assurance protocols were followed.
Peak areas were converted to organic carbon concentrations by first
correcting for the instrument blank, measured with carbon-free distilled
water (CFDW), then dividing the result by the instrument response factor
determined with organic compound standards (glucose, KHP or
glucoseamine) in seawater. The instrument response factor was measured
twice daily (at the beginning and end of the day=s runs using high and
low TOC standards) and the instrument blank was repeatedly measured
throughout the day, typically after every four to six samples. While the
instrument blank exhibited a generally decreasing value throughout the
lifetime of each furnace tube, the instrument response factor varied
less than 5% of the mean value over the course of the analysis period
and several furnace tube lifetimes.

The CFDW used to measure the instrument blank was obtained from a
Milli-QJ water purification system (Millipore, Bedford, MA). This water
was consistently found to have the lowest total blank of all the CFDWs
tested in multiple direct, head-to-head comparisons. Consequently, it
was assigned a residual TOC concentration of 0.0 μmol C and no back
correction of the measured TOC values was required. It should be noted
that even though this lot of CFDW gave the lowest total blanks, this
fact does not guarantee that it did not contain some residual carbon. If
at some future date it can be shown that this CFDW did contain some
amount of TOC, then the values reported here would need to be revised
upwards by this amount. However, such a correction could not exceed the
measured total blanks, which were on the order of 6B8 μmol C/L.

TOC values are reported as μmol C/kilogram seawater (μmol/kg). The
measured concentration (μmol/L) is converted to μmol/kg by dividing by
the density of the sample at the time of the analysis. Sample density is
calculated from the measured salinity and lab temperature using the
international equation of state of seawater (Millero and Poisson, 1981).
The bottle salinity was used whenever available, otherwise the
corresponding CTD salinity measured on the downcast was used. For sample
temperature, the measured lab temperature at the time of analysis was
used.

**2.9 Salinity**

Salinity samples were collected in 125-mL amber glass bottles directly
from the rosette, taking care not to touch the petcock. Bottles were
rinsed twice and overflowed one half volume; new caps were used for each
sample.

Bottle salinities were measured using a GuildlineJ 8400 Autosal and #114
standard seawater in a temperature-controlled van. Conductivity ratios
were converted to salinities conforming to the PSS78 standard. If there
was no bottle salinity available for a given sample position, the CTD
value was used in calculations requiring a salinity measurement.

**3.0 DATA TABLES**

A complete listing of the CTD data is available through NOAA (McTaggart
*et al*., 1994). Discrete data are reported at all observed depths
(Appendix A). Where no data is available, a null value is inserted. A
quality control column is located next to most of the observed
parameters; quality control flags follow the WHP Data Reporting
Requirements (WOCE Operations Manual, 1991), and are listed in Table 6.
In addition, Table 7 displays unique quality control flags for fCO~2~.
Sigma-theta (σθ) and potential temperature (θ) values listed in the
tables were calculated using standard UNESCO algorithms (Fofonoff and
Millard, 1983). Input parameters include salinities and in-situ
temperatures from the CTD. Header information at the top of each page
includes an operation number consisting of year, Julian date, and GMT at
time-at-depth. The Sample ID listed in the data tables consists of the
cast number followed by the 2 digit NiskinJ rosette position. Due to the
loss

Table 6. WOCE data quality flag definitions.

2 Acceptable measurement

3 Questionable measurement

4 Bad measurement

9 Sample not drawn for measurement

Table 7. Unique quality control flag definitions for fCO~2~.

Fugacity of CO~2~

A No DIC available for calculation

B No sigma theta available for calculation

D Estimated DIC used in calculation

E Estimated sigma theta used in calculation

of the 24-position rosette during Leg 4, and the subsequent requirement
to take two 12-position rosette casts per station to maintain our
sampling density, those respective stations are contained in two
separate data tables indicated by different cast numbers within Appendix
A. To obtain the data base by remote access, please see page iii of this
report.

**4.0 ACKNOWLEDGMENTS**

The assistance of the officers and crew of the NOAA Ship *Discoverer* is
gratefully acknowledged. The authors also wish to thank Ryan Whitney for
manuscript preparation, and the critical review of John Bullister and
Jim Johnson of PMEL. Jim Gendron, also of PMEL, is acknowledged for
formatting the data tables in Appendix A. This research was supported by
the Climate and Global Change Program of NOAA as part of the joint
NSF/NOAA sponsored U.S. JGOFS Equatorial Pacific Process Study. We thank
Drs. James F. Todd of the NOAA Office of Global Programs and Neil
Anderson of the National Science Foundation for their efforts in the
coordination of this joint study.

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Johnson, K.M., A.E. King, and J. McN. Sieburth (1985): *Coulometric
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Johnson, K.M. (1992): Operator=s manual; Single operator multiparameter
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McTaggart, K., and L. Mangum (1994): CTD/O~2~ measurements during 1991
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Millero, F.J., and A. Poisson (1981): International one-atmosphere
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**APPENDIX A**

**TABULATED DISCRETE BOTTLE DATA**

**APPENDIX B**

**DISSOLVED OXYGEN DUPLICATES**

Appendix B: Dissolved oxygen duplicates of the boreal autumn EqPac 1992
cruise.

Date Latitude Longitude Sta \# Pressure O~2~ % deviation from 1st

\(N\) (W) (db) (μmol/L)

***Samples collected from 13 separate NiskinJ bottles on same cast***

***LEG 3:***

9/16/92 0 140 12 1000 86.2

9/16/92 0 140 12 1000 82.8

9/16/92 0 140 12 1000 83.9

9/16/92 0 140 12 1000 83.1

9/16/92 0 140 12 1000 82.9

9/16/92 0 140 12 1000 83.3

9/16/92 0 140 12 1000 82.7

9/16/92 0 140 12 1000 83.0

9/16/92 0 140 12 1000 83.2

9/16/92 0 140 12 1000 83.5

9/16/92 0 140 12 1000 82.7

9/16/92 0 140 12 1000 83.0

9/16/92 0 140 12 1000 82.5

83.3 Mean of 13

0.9 Std. Dev.

1.1 % Rel. Error

***Double-trip Duplicates***

***LEG 3:***

9/12/92 9 140 3 1000 34.0

9/12/92 140 3 1000 34.4 B1.18

9/12/92 8 140 4 1000 37.4

9/12/92 140 4 1000 36.5 2.41

9/13/92 6 140 5 1000 50.5

9/13/92 140 5 1000 50.5 0.00

9/13/92 5 140 6 1000 56.9

9/13/92 140 6 1000 56.3 1.05

9/13/92 4 140 7 1000 52.5

9/13/92 140 7 1000 52.3 0.38

9/14/92 3 140 8 1000 69.4

9/14/92 140 8 1000 69.6 B0.29

9/14/92 2 140 9 1000 74.3

9/14/92 140 9 1000 74.2 0.13

9/14/92 1 140 10 1000 84.7

9/14/92 140 10 1000 84.4 0.35

9/15/92 0.50 140 11 1000 84.1

9/15/92 140 11 1000 83.2 1.07

9/15/92 0 140 12 1000 86.9

9/15/92 140 12 1000 83.0 4.49

9/15/92 0.25 140 13 1000 83.9

9/15/92 140 13 1000 83.1 0.95

9/16/92 B0.50 140 15 1000 85.7

9/16/92 140 15 1000 86.9 B1.40

9/16/92 B1 140 16 1000 93.6

Appendix B: Dissolved oxygen duplicates. (continued)

Date Latitude Longitude Sta \# Pressure O~2~ % deviation from 1st

\(N\) (W) (db) (μmol/L)

***LEG 3 (continued):***

9/16/92 140 16 1000 92.9 0.75

9/17/92 B2 140 17 1000 90.5

9/17/92 140 17 1000 89.6 0.99

9/17/92 B3 140 18 1000 91.3

9/17/92 140 18 1000 91.4 B0.11

9/18/92 B4 140 19 1000 99.1

9/18/92 140 19 1000 98.6 0.50

9/19/92 B5 140 20 1000 92.7

9/19/92 140 20 1000 92.2 0.54

9/21/92 B6 140 21 1000 90.7

9/21/92 140 21 1000 90.5 0.22

9/21/92 B7 140 22 1000 100.0

9/21/92 140 22 800 98.5 1.50

9/23/92 B10 140 23 1000 90.4

9/23/92 125 23 1000 90.3 0.11

9/23/92 B10 125 24 1000 78.7

9/23/92 125 24 1000 78.7 0.00

9/23/92 B7 125 25 1000 91.5

9/23/92 125 25 1000 91.7 B0.22

9/24/92 B6 125 26 1000 88.4

9/24/92 125 26 1000 89.7 B1.47

9/25/92 B5 125 27 1000 92.2

9/25/92 125 27 800 91.7 0.54

9/25/92 B4 125 28 1000 94.9

9/25/92 125 28 1000 94.6 0.32

9/26/92 B3 125 29 1000 88.0

9/26/92 125 29 1000 87.7 0.34

9/26/92 B2 125 30 1000 87.5

9/26/92 125 30 800 87.6 B0.11

9/27/92 B1 125 31 1000 86.0

9/27/92 125 31 1000 86.1 B0.12

9/27/92 B 0.50 125 32 1000 84.0

9/27/92 125 32 1000 83.6 0.48

9/27/92 B 0.25 125 33 1000 84.5

9/27/92 125 33 1000 84.2 0.36

9/28/92 0 125 34 1000 84.6

9/28/92 125 34 1000 84.4 0.24

9/28/92 0.25 125 35 1000 80.7

9/28/92 125 35 1000 81.9 B1.49

9/29/92 0.50 125 36 1000 81.8

9/29/92 125 36 1000 81.4 0.49

9/29/92 1 125 37 1000 79.2

9/29/92 125 37 1000 78.9 0.38

9/30/92 2 125 38 1000 73.7

9/30/92 125 38 1000 73.3 0.54

10/1/92 3 125 39 1000 74.1

10/1/92 125 39 1000 74.3 B0.27

10/1/92 4 125 40 1000 63.9

10/1/92 125 40 1000 64.9 B1.56

Appendix B: Dissolved oxygen duplicates. (continued)

Date Latitude Longitude Sta \# Pressure O~2~ % deviation from 1st

\(N\) (W) (db) (μmol/L)

***LEG 3 (continued):***

10/1/92 5 125 41 1000 54.8

10/1/92 125 41 800 54.6 0.36

10/5/92 6 125 42 1000 55.5

10/5/92 125 42 1000 56.0 B0.90

10/5/92 8 125 44 1000 41.3

10/5/92 125 44 800 39.7 3.87

10/6/92 9 125 45 1000 37.5

10/6/92 125 45 1000 15.1 59.73

10/6/92 10 125 46 1000 42.5

10/6/92 125 46 1000 41.6 2.12

1.81 Mean % deviation

9.23 Std. Dev. %

***LEG 4:***

10/29/92 10 110 50 1000 30.5

10/29/92 110 1000 30.7 B0.66

11/1/92 8 110 51 1000 35.1

11/1/92 110 1000 35.1 0.00

11/2/92 6 110 52 1000 48.8

11/2/92 110 1000 49.2 B0.82

11/2/92 5 110 53 1000 56.3

11/2/92 110 1000 55.4 1.60

11/3/92 4 110 54 1000 54.2

11/3/92 110 1000 55.6 B2.58

11/3/92 3 110 55 1000 70.5

11/3/92 110 1000 70.3 0.28

11/4/92 1 110 57 1000 76.3

11/4/92 110 1000 75.7 0.79

11/4/92 0.5 110 58 1000 82.7

11/4/92 110 1000 82.7 0.00

11/5/92 0.25 110 59 1000 84.0

11/5/92 110 1000 83.6 0.48

11/5/92 0.18 110 60 1000 83.4

11/5/92 110 1000 82.6 0.96

11/6/92 0 110 61 1000 80.5

11/6/92 110 1000 80.5 0.00

11/7/92 B0.25 110 62 1000 84.8

11/7/92 110 1000 83.4 1.65

11/8/92 B0.5 110 63 1000 86.4

11/8/92 110 1000 85.9 0.58

11/8/92 B1 110 64 1000 84.9

11/8/92 110 1000 84.4 0.59

11/8/92 B2 110 65 1000 75.7

11/8/92 110 1000 75.6 0.13

11/8/92 110 1000 76.0 B0.40

11/9/92 B3 110 66 1000 92.7

11/9/92 110 1000 93.0 B0.32

11/11/92 B5 110 68 1000 97.7

11/11/92 110 1000 96.5 1.23

Appendix B: Dissolved oxygen duplicates. (continued)

Date Latitude Longitude Sta \# Pressure O~2~ % deviation from 1st

\(N\) (W) (db) (μmol/L)

***LEG 4 (continued):***

11/12/92 B6 110 69 1000 88.1

11/12/92 110 1000 87.2 1.02

11/12/92 B8 110 70 1000 76.0

11/12/92 110 1000 77.1 B1.45

11/14/92 B10 110 71 1000 73.8

11/14/92 110 1000 72.3 2.03

11/15/92 B2 110 72 1000 70.7

11/15/92 110 72 1000 69.8 1.27

0.29 Mean % deviation

1.08 Std. Dev. %

***LEG 5:***

11/22/92 B5 82 77 800 35.1

11/22/92 82 77 800 34.0 3.13

11/22/92 B5 82 78 800 33.1

11/22/92 82 78 800 32.9 0.60

11/22/92 B5 82 79 800 31.5

11/22/92 82 79 800 31.6 B0.32

11/22/92 B5 82 80 800 42.9

11/23/92 82 80 800 42.2 1.63

11/23/92 B13 78 78 800 24.0

11/23/92 78 81 800 22.9 4.58

11/24/92 B13 78 82 800 30.6

11/24/92 78 82 800 30.0 1.96

11/24/92 B13 78 83 800 27.3

11/24/92 78 83 800 26.7 2.20

11/25/92 B12 78 84 800 31.1

11/25/92 78 84 800 30.5 1.93

11/25/92 B12 78 85 800 5.9

11/25/92 78 85 800 4.9 16.95

11/26/92 B13 81 87 800 30.3

11/26/92 81 87 800 30.1 0.66

11/27/92 B13 84 88 800 28.9

11/27/92 84 88 800 28.9 0.00

11/27/92 B13 86 89 800 36.9

11/27/92 86 89 800 36.3 1.63

11/28/92 B13 89 91 800 34.3

11/28/92 89 91 800 33.4 2.62

11/28/92 B14 92 92 800 34.6

11/28/92 92 92 800 34.2 1.16

11/28/92 B14 95 93 800 40.4

11/28/92 95 93 800 39.4 2.48

11/29/92 B12 95 95 800 50.5

11/29/92 95 95 800 50.6 B0.20

11/29/92 B10 95 96 800 31.5

11/29/92 95 96 800 30.4 3.49

11/29/92 B8 95 97 800 40.7

11/29/92 95 97 800 37.4 8.11

11/30/92 B6 95 98 800 44.1

Appendix B: Dissolved oxygen duplicates. (continued)

Date Latitude Longitude Sta \# Pressure O~2~ % deviation from 1st

\(N\) (W) (db) (μmol/L)

***LEG 5 (continued):***

11/30/92 95 98 800 47.3 B7.26

11/30/92 B5 95 99 800 71.5

11/30/92 95 99 800 71.4 0.14

12/1/92 B4 95 100 800 62.7

12/1/92 95 100 800 62.6 0.16

12/1/92 B3 95 101 800 61.0

12/1/92 95 101 800 62.1 B1.80

12/1/92 B2 95 102 800 65.2

12/1/92 95 102 800 65.0 0.31

12/2/92 B1 95 103 800 68.1

12/2/92 95 103 800 68.1 0.00

12/2/92 0 95 104 800 49.8

12/2/92 95 104 800 50.0 B0.40

12/3/92 1 95 105 800 52.1

12/3/92 95 105 800 52.3 B0.38

12/4/92 2 95 106 800 55.1

12/4/92 95 106 800 54.7 0.73

12/4/92 3 95 107 800 39.6

12/4/92 95 107 800 38.8 2.02

1.65 Mean % deviation

3.92 Std. Dev. %

[^1]: NOAA, Pacific Marine Environmental Laboratory (PMEL), 7600 Sand
    Point Way NE, Seattle, WA 98115-0070.

    ^2^ NOAA, Atlantic Oceanographic and Meteorological Laboratory
    (AOML), 4301 Rickenbaker Causeway, Miami, FL 33149.

    ^3^ Rosenstiel School of Marine and Atmospheric Sciences (RSMAS),
    University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149.

    ^4^ Department of Marine Science, University of South Florida, St.
    Petersburg, FL 33701.

    ^5^ Department of Chemistry, Woods Hole Oceanographic Institution,
    Woods Hole, MA 02543.