Seasonal study of carbon dioxide in the southern extreme of the pacific sector, Antarctic Ocean. Progress report Page: 4 of 16
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This report describes the progress made during the six-month period between December 1,
1993, when this grant was awarded, and May 1, 1994. The major aim of this investigation is to
measure the distribution of the total CO2 concentration and pCO2 in seawater in the Pacific sector
of the extreme Southern Ocean as far south as 780S. The areas investigated include the continental
shelf areas in the Ross,, Amundsen and Bellingshausen Seas and the off-shore deep water areas as
far north as 670S. The measurements were made aboard the R/VIB NATHANIEL B. PALMER
between February 14, 1994 and April 5, 1994, and the preliminary results are briefly described in
this report. This expedition constitutes the first of a pair expeditions. The first is designed
investigate oceanic CO2 sink/source conditions during the austral summer. The second expedition,
which is designed for the following winter, has been scheduled for September, 1994.
2. DESCRIPTION OF THE SUMMER EXPEDITION, FEBRUARY-APRIL, 1994
The expedition started at McMurdo Station, Ross Island, Antarctica, on February 14, 1994,
and was completed on April 5, 1994, at Punta Arenas, Chile. The ship's tracks and station
locations are shown in Fig. 1. During the 51 days at sea, the total CO2 concentration, pCO2 in
seawater and marine air were measured by John G. Goddard (party chief), Stephany I. Rubin and
Dee Breger. The total CO2 concentration and pCO2 in discrete seawater samples were measured
using a coulometer (Chipman et al., 1993) and gas chromatograph (Chipman et al., 1993)
respectively. The pCO2 measurements were made at 4.0 C. In addition, surface water pCO2 was
determined continuously using a shower-type equilibrator and infrared CO2 analyzer (Broecker
and Takahashi, 1966). A total of 1,644 discrete water samples were collected in 10-liter Niskin
sampling bottles at 154 stations during the expedition at varying depths ranging from the sea
surface to the sea floor. Out of these, 1,239 samples were analyzed for pCO2 and 1,308 were
analyzed for the total CO2 concentration. Since the pCO2 measurements were made in duplicates
and the coulometer for total CO2 measurements were calibarted often using a gas pipette and
tested using Standard Reference Solutions, the actual number of analyses made at sea doubles the
number of samples for each of the properties. A total of 312 measurements was made for 74
Standard Reference Solutions (Batch #18 with a total CO2 concentration of 2115.09+1.09 umol/kg
(N=7)) provided by Andrew Dickson of Scripps Institution of Oceanography. The underway pCO2
system was successfully operated for nearly 80% of time at sea. Whenever the ship's water in-take
was blocked by ice fragments, the underway pCO2 measurement had to be discontinued.
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Takahashi, Taro; Goddard, J. G.; Rubin, S. I. & Breger, D. Seasonal study of carbon dioxide in the southern extreme of the pacific sector, Antarctic Ocean. Progress report, report, May 5, 1994; United States. (https://digital.library.unt.edu/ark:/67531/metadc1341008/m1/4/: accessed April 25, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.