US JGOFS Antarctic Environments Southern Ocean Process Study (AESOPS)

Revelle Leg KIWI06, APFZ Survey 1, October - November 1997 

Documentation for: THE HYDROGRAPHIC BOTTLE DATA 

L.A. Codispoti (lou@ccpo.odu.edu)
Old Dominion University,  October 1998


General Comments:

This "readme" file pertains to the salinity, dissolved oxygen, and nutrient
data taken from sampling bottles with the hydrographic rosette that was
equipped with 24 ~10-liter "Niskin-like" Bullister Bottles made mostly of PVC
and equipped with orange silicone o-rings during Revelle leg RR06
(October-November 1997).  Dr. Tim Cowles of the College of Oceanic and
Atmospheric Sciences at Oregon State University (cowles@oce.orst.edu) was the
chief scientist during this leg. This cruise was the first survey leg on the
R/V Roger Revelle during the U.S. JGOFS program in the Southern Ocean
(AESOPS).  The Revelle legs focused on the Polar Front region and complemented
several AESOPS cruises on board the R/V Nathaniel Palmer which focused on the
Ross Sea.  Several casts with a trace metal clean rosette equipped with 8,
30-l Go-Flo bottles were also taken during this leg until this instrument was
lost on 13 November. These data are not reported here because this system was
not designed to produce hydrographic data of "WOCE quality".  These trace
metal rosette data have been submitted to the U.S. JGOFS data base as
separate files. Additional hydrographic data were collected by other research
teams, and will be submitted to the data base by these groups.  These
additional observations included observations from towed undulating devices 
and from trace metal clean bottle casts made by hanging bottles on Kevlar
cable. Investigators interested in these data can find out about their status
by consulting the chief scientist. 

Some questionable data are not included in this report. These data are
available upon request. 

No units are given for salinity in this report because the most recent
definitions of salinity define it as a dimensionless number.  To accommodate
every preference, Winkler oxygen values are reported in ml/l, micromolar and
micromoles per kg.  The latter values can only be calculated with a knowledge
of the oxygen sample temperatures when the samples were drawn. These "draw
temperatures" are not reported here, but can be obtained by contacting
lou@ccpo.odu.edu.  Nutrient values are reported in micromolar. They can be
converted to micromoles per kg, by combining laboratory temperature on the 
Revelle (approx. 21 deg. C during this leg) and the salinity of the sample to
compute density and then dividing the value in micromolar by this number.

Methods:

In general, the methods employed for the bottle salinity, Winkler dissolved
oxygen, and nutrient analyses did not differ significantly from those
described in the JGOFS protocols that were distributed in 1994 (UNESCO, IOC
Manual and Guide #29). Minor differences included the following: 1) Sea Bird
CTD systems and bottle carousels were employed (SBE-9+ underwater units,
SBE-11 deck units, SBE-32 carousels).  These units represent a newer
generation of equipment than the instruments described in the JGOFS protocols. 
2) The protocols give one a choice of adjusting nutrient methods so that 
calibration curves are strictly linear, or opting for more response and taking
into account non-linearities.  We choose the latter method.  3) No corrections
were made for "carryover" between nutrient samples run on the Technicon
Autoanalyzer. Carryover effects in our nutrient analyses are generally less
than ~2% of the concentration difference between adjacent samples, and were
minimized by arranging samples in depth order, etc. in some cases.  4)
Calibration and re-calibration of volumetric ware were not exactly as
described in the JGOFS protocols, but all volumetric flasks, maxipettors, and
dosimats were all calibrated. 5)Duplicate oxygen samples were not routinely
drawn. 6) The JGOFS protocols do not describe an automated technique for the
analysis of ammonium concentrations.  We employed the Berthelot reaction
using a method somewhat similar to the method described by Whitledge et al.
(1981, Whitledge, T.E., Malloy, S.C., Patton, C.J. and Wirick, C.D. Automated
Nutrient Analyses in Seawater. Brookhaven National Laboratory Rept.  BNL
51398, 216pp.).  

Temperature:

The temperature data associated with each bottle depth were taken by the CTD
system during the bottle tripping process.  Consult the companion CTD data
report for this cruise to learn more about the CTD system.

Sampling:

The samples in this report were taken from ~10 liter Bullister bottles.
Because there is little or no lag time between triggering a bottle and bottle
closure with the new SeaBird rosette systems, our sampling protocols request
that bottles be held at the sampling depth for at least 30 seconds before
tripping.

NOTE THAT THE MID-POINT OF THE SAMPLING BOTTLES WAS  ~1 METER ABOVE THE CTD
SENSORS.  THE DATA HAVE NOT BEEN CORRECTED FOR THIS OFFSET. 

Salinity:

Salinities were determined with Guildline Autosal salinometers. New vials of
standard sea-water were used to standardize before and at the end of every
run. Agreement between bottle salinities and the recently calibrated sensors
on the Sea Bird CTD systems was usually better than 0.01  before post-cruise
data processing which employs the bottle salinities to correct the CTD
salinities. More information on the quality of the salinity data are given in
the companion CTD report. 

Dissolved oxygen:

The Winkler dissolved oxygen apparatus was built and supplied by the SIO/ODF
group.  This system is computer controlled and detects the end-point
photometrically.  Temperatures of the thiosulfate and standard solutions are
automatically monitored by this system.  

Nutrients:

Note that the terminology used to describe nutrients has become somewhat loose
over the years and that silicate = silicic acid, dissolved silicon or reactive
silicate, and phosphate = reactive phosphorus.  Nutrient analyses were
performed on a 5-channel Technicon II AA system that was modified and provided
by Doug Masten (doug@odf.ucsd.edu) of  the ODF group at the  Scripps
Institution of Oceanography.

Queries:

Questions about these data may be addressed to:

Dr. L. A. Codispoti
CCPO
Old Dominion University
Norfolk, VA 23529