WHP Ref. No.: PR6
Last updated: 15 March 1995

			CRUISE REPORT 
		Repeat hydrography on Line PR6

A.	 Cruise narrative

A.1.	 Highlights
a.	 WOCE designation: 	PR6
b.	 Expedition designation:18DD9501/1
c.	 Chief scientist: 	Frank Whitney
				Institute of Ocean Sciences
				P.O. Box 6000
				9860 West Saanich Road
				Sidney, B. C. V8L 4B2
				Telephone: 604-363-6816
				Telefax: 604-363-6807
				Internet: whitney@ccs.ios.bc.ca
d.	 Ship: 			John P. Tully
e.	 Ports of call: 	Patricia Bay, B.C.
f.	 Cruise dates: 		February 7 to February 23, 1995

A.2.	 Cruise Summary Information

a. Geographic boundaries: Line PR6 starts at the mouth of Juan de Fuca Strait 
on the west coast of Canada, and heads almost due west for 900 n mi. The 
terminal station is PRS1, formerly designated Ocean Weather Station Papa (50øN, 
145øW). 

b. Stations occupied: The stations occupied on the cruise are tabulated by type 
in Tableø1.

TABLE 1:  Table of stations by type
Sample type:		No. Stations:	Max. Depth (m):
CTD casts		33		4300ødbar
Rosette/Hydro casts	4		4200
Loop samples		36		5
Moorings		2		1000

c.Floats and drifters deployed:  A drifting sediment trap line was deployed for 
3 days at Station PRS1. On recovery, the trap line was cut by the ship's 
propeller resulting in the loss of all traps. 
 A 230ømm mesh net was used to collect mesozooplankton. In addition, at PRS1 an 
in situ drifter was deployed for 7 hours to measure primary production rates.

A.3.	 List of Principal Investigators

Principal Investigator 	Parameters			Institution
Howard Freeland		Ocean Physics 			IOS
C. S. Wong		Climate Chemistry		IOS
			CO2, biological measurements
Frank Whitney		Coordinator			IOS
			Nutrients

A.4.	 Scientific Programme and Methods

This joint WOCE/JGOFS cruise continued measurements of water property changes 
seasonally and inter-annually.   Sampling was not as intensive as in past 
cruises, since we are still recovering from Line P15N and JGOFS awaits fresh 
funding. 

Under WOCE, a CTD survey along Line PR6 was completed, but weather restricted 
our rosette casts to 4 stations (7 were planned). Salinity, oxygen and 
nutrients (NO3ø+øNO2, PO4 and Si) were analyzed onboard ship. 
JGOFS participants sampled plankton at several stations, and incubated water to 
measure growth and grazing rates of plankton. Continuous fluorescence 
measurements estimated chlorophyll in surface waters.   Occasional water 
samples were taken from 15 m for the assessment of flavodoxin a marker for in 
situ iron limitation of phytoplankton growth.

Preliminary Results

Typical winter conditions were encountered along Line PR6. In surface waters, 
nitrate has increased slightly over what was measured last February, reversing 
a 5 year trend of decreasing winter nutrient levels. 

Goals Achieved

Complete CTD survey of Line PR6. 
Successful Rosette casts at 4 stations on Line P.
Completion of JGOFS sampling for plankton and productivity measurements.

A.5.	 Major Problems and Goals Not Achieved

Rosette misfires resulted in several lost samples. 

Less water sampling was completed than had been planned, due to poor weather.

A drifting sediment trap line was deployed for 3 days at Station PRS1. On 
recovery, the trap line was cut by the ship's propeller resulting in the loss 
of all traps.

A.6.	Other Incidents of Note

None noted. 

