CRUISE REPORT:  Repeat hydrography on Lines PR5 & PR6
			    WOCE Cruise No. 18DD9309/1

Chief Scientist: Frank Whitney
Ship: John P. Tully
Ports of Call:  none
Cruise Dates: May 14 to June 1, 1993
Expedition Designation: 18DD9309/1

Cruise Narrative

IOS WOCE and UBC JGOFS both completed successful programs on this cruise to Station Papa (PS1).  WOCE sampling included 55 CTD and 10 Rosette casts to provide chemical data and CTD calibration salinities.  Onboard analyses included salinity, oxygen, nitrate, nitrite, phosphate, silicate, hourly air and sea surface pCO2, and chlorophyll a.  
The JGOFS program measured biological productivity at 5 stations along Line PR6, conducting many deck incubations to measure C and N uptake rates.  
A warm water anomaly of 1.5oC above the long term average extended well off coast.  In this water, zooplankton were dominated by salps, with Vellela also being moderately abundant.  

Cruise Summary Information

Lines PR5 and PR6 were completed, although sampling depth was limited by the length and strength of CTD cable, and by damage  to our hydro wire.  We tested our Lantec winch with Rosette casts as deep as 3700 dbar, improving its speed controls in the process.  A combination of cable age, weather and winch used limited our sampling depth to a maximum of between 3000 and 3700 dbar. 

	Table of Stations by type
Sample type:
No. stations:
Max. depth:

CTD casts
54
3700 db

Rosette casts
9
3600 db

Loop samples
58
5 m

 Moorings
4
4260 m


Floats and Drifters deployed
	A drifting sediment trap line was deployed for 3 days at Station P26.  Particulate materials were collected on filters for measurements of total, carbon and nitrogen fluxes.  
	At MP32, an Argos drifter drogued at 100 m, was hand deployed.

Moorings deployed and recovered
	A current meter mooring was serviced and redeployed near P20.  
A single sediment trap was anchored 500 m above the bottom in 1300 m of water near P04.  At station P26, two moorings with traps at 250 and1000 m, and at 3800 m were deployed.

Principal Investigators  
Howard Freeland
Climate change 
IOS

C.S. Wong
Climate chemistry
IOS

Ron Perkin
Physical measurements
IOS

Frank Whitney
Chemical measurements
IOS


Preliminary Results
Modifications made to the Lantec winch give us confidence that this winch will handle our deep ocean sampling needs on our next cruise (February 1994).  Cable loads caused some concern, reaching 4000 lb in heavier swells.  Our simple heave damping system, a rubber bungie that allows the CTD block to travel up to 10 feet, was proven effective in reducing peak loads.   

Goals Achieved
CTD surveys of PR5 and PR6 to 3000 m (max. 3700 m) completed.
Rosette sampling to 3000 m (max. 3600 m) successful at 9 stations.
JGOFS sampling for plankton, uptake measurements and N cycling completed.
Moorings recovered (2) and deployed (4).
Further testing of Lantec winch was successful to 3600 m.  Spooling and winch controls work well after alterations.

Problems and Goals not Achieved
A broken strand in our hydro wire eliminated any deep sampling; few samples below 3000 m were collected.  

Cruise Participants & Affiliations
F.A. Whitney
Nutrients
IOS

N. Hall-Patch
CTD/Rosette
IOS

B.G. Minkley
T/S/O
IOS

R. D. Bellegay
Trap moorings/sampling
IOS

R. Bigham
Mooring/sampling
IOS

T.J. Soutar
Electronics, pCO2
IOS

P. Boyd
Primary Productivity
DOUBC

D. Varela
N cycling
DOUBC

H. McLean
Zooplankton/sampling
DOUBC

S. Doherty
nano-plankton
DOUBC

M. Wen
zooplankton
DOUBC

S. Ruskey
lab assistant
DOUBC

J. Wu
natural 15N and 13C
DOUBC

M. Robert
CTD/sampling
McGill University 

Institute of Ocean Sciences, Sidney, B.C., Canada.
Department of Oceanography, University of B.C., Vancouver, B.C.

Measurement Techniques and Calibrations
Water sampling
	A General Oceanics Rosette holding 23 10 L Niskin samplers, and a Guildline Model 8737 CTD was used for routine sampling in the upper 3000 m of the water column.  Cable was not reliable enough to routinely venture deeper. 
	Trace metal samplers used 30 L Go-Flo samplers on Kevlar line.
	Productivity, POC/N, chlorophyll and some nutrient samples were collected with 10 L Go-Flo samplers on Kevlar line.
	A sea water loop consisting of an intake at 4 m, a thermosalinograph well, a pump, insulated PVC tubing and a manifold at a laboratory sink, supplied water continuously to a pCO2 equilibrator and for miscellaneous sampling.  This sampling is denoted USW (uncontaminated sea water) in the .SUM file.

Oxygen 
	An automated tirtation system (Brinkman Dosimat) using the micro-Winkler method (Carpenter, 1965) detected the iodine end-point colorimetrically.  Duplicate samples came from pairs of Niskin bottles that were tripped within 2 min and 2 db of eachother.

Depth Range     (m)
Conc. Range (uM/kg)
Sp of pairs  

300 to 3000
15 to 115
0.95 (k=11)


Where the standard deviation of pairs Sp = {(sum d2)/2k}1/2, d is difference between pairs, and k is the number of pairs.  The rather high Sp likely reflects the inexperience of some samplers.  Samples taken from 4 Niskins tripped at 3001 +/- 0.4 m had oxygen concentraions of 100.5 +/- 0.15 umol/kg.  
Standards were prepared as outlined in WOCE Report 73/91.  
Quality checks:
Sample 35 - oxygen sample saturated with an air bubble - flagged with 3.	
Sample 102 -  oxygen sample has large air bubble - flagged with 3.
P26-2 profile, samples 126 to 148 - problems with probe stability, changed colorimeter - data flagged 3.
Plotted all oxygen data from the cruise and there were no outliers.

Nutrients
	Samples were collected in polystyrene tubes (16 x 125 mm) and refrigerated for a maximum of 8 h (Rosette) or 30 h (USW)  before being analyzed.  Four nutrients analysed by Technicon procedures were NO3&NO2, NO2, PO4 and Si.  Check standards were analyzed in mid-profile and concentrations calculated  as a check on system performance.
  

Std. deviation
n of check std.

Nitrate
0.38 
26

Nitrite
0.008
14

Phosphate
0.03
15

Silicate
0.61
26


	Concentrated standards were prepared on 6 Jan 93 from oven dried (80oC) reagents.

Reagent
Concentration  (g/L)
Std 1
(umol/L)
Std 2
(umol/L)
Std 3
(umol/L)
Std 4
(umol/L)

KNO3
0.25252
12.0
24.0
36.0
48.0

Na2SiF6
1.40945
44.97
89.94
134.91
179.88

NaNO2
0.00845
0.49
0.98
1.47
1.96

KH2PO4
0.03409
1.002
2.004
3.006
4.008








Working standards were made every 1 to 2 days by diluting 1 to 6 mL of various stock solutions to 250 mL with 3.2% NaCl (w/v in double run Milli-Q water).  

Pooled standard deviation of pairs, Sp = 0.01 uM/kg PO4, 0.12 uM/kg NO3, and 0.32 uM/kg SiO4 for 14 pairs of Niskins, each pair tripped within 9 db of eachother. 

Laboratory Temperatures:
Varied between 19 and 25 oC, and were recorded approximately hourly during analyses.

Comments on nutrient analyses:
NO3 - at station P04, standard curves were strongly non-linear.  To improve linearity of NO3 standards, the sample flow was decreased from 0.32 to 0.16 mL min-1 after the first station.  
NO2 - not analyzed at J05 because reagents ran short.
PO4 - a connector leaked during stations P26-2 and R16.  This caused a reduced sample flow and produced results that were erratic. P26 samples were run again after cool storage in polystyrene tubes for 2d.   Data from this profile are lower than long term averages, and are flagged with 3.
Sample 31 is high due to bad peak formation - flagged with a 3.
Sample 36 is high - flagged with 3.
Sample 155 sucked air - flagged as sample lost - data quality 5.
Plotted all PO4 data from cruise and there seems to be more station to station scatter than is typical.  Perhaps there were problems with the splitter leaking during the entire cruise.


Salinity
	Samples were collected in glass bottles and analyzed onboard ship using a Guildline Model 8410 Portasal.  The Portasal was standardized daily with IAPSO standard sea water Batch  P118, 11/91.  Precision is estimated from samples drawn from pairs of Niskin samplers tripped at the same depth (within 2 db).

Depth Range     (dbar)
Conc. Range (psu) 
Sp 

300 to 3000
33.9 to 34.7
0.00086 (k=11)


Where the standard deviation of pairs Sp = {(sum d2)/2k}1/2, d is difference between pairs, and k is the number of pairs.   From 4 Niskins tripped at 3001 db, salinities were 34.6519 +/- 0.0006. 
Data Checks:
Sample 198 is low indicating bottle not tripped at correct depth. BTLNBR labelled as 4 (did not trip correctly) and flagged all samples with 3 (questionable values), although the analyses were good.
Values for samples 189 and 192 are high indicating bottle did not trip at the correct depth. BTLNBR labelled as 4 and all samples flagged with 3.

CTD
The CTD probes (Models 8737 and 8705) used during this cruise are made by Guildline Instruments of Smiths Falls, Ontario, Canada. Their resolution and accuracy will be provided when data is submitted.

References

Carpenter, J.H.  1965. The Chesapeake Bay Institute technique for the Winkler dissolved oxygen method.  Limnol. Oceanogr., 10: 141-143.
