CRUISE REPORT

Vessel: RV Bjarni Sæmundsson

Departure: Reykjavík, Iceland, November 4th 1998

Arrival: Reykjavík, Iceland, December 1st 1998

PARTICIPANTS:

Jóhannes Briem, Chief scientist

Héðinn Valdimarsson, Physical oceanography

Magnús Danielsen, Chemical Oceanography

Hjálmar Vilhjálmsson, Capelin

Sigurður Gunnarsson, Capelin

Björn Sigurðarsson, Capelin

SCIENTIFIC OBJECTIVES

The B12-98 cruise was carried out by the Marine Research Institute (MRI) on the RV Bjarni Sæmundsson with the following aims:

1. To carry out long-term hydrographic investigations on standard sections in the waters all around Iceland. The work included CTD-casts together with sampling for nutrient and oxygen analysis. Included in the observation work is MRI's role in VEINS, a program with the objective of measuring and modeling the variability of fluxes between the Arctic Ocean and the Atlantic with view on implementing a longer term system of measurements needed to understand the high-latitude oceans steering role in decadal climate variability. Funding is provided by the EU MAST-III programme and the participants in the project. The work on this cruise was part of the following VEINS tasks:
   1. Determining the water mass properties of the Denmark Strait Overflow. (Task 1.4.2)
   2. Improving estimation of the freshwater flux to the North Atlantic via the East Greenland Current and East Icelandic Current. (Task 1.4.3)
   3. Measuring the inflow of Atlantic Water to the Iceland Sea. (Task 1.4.4)

2. Service a VEINS mooring in the East Icelandic Current (KR4, VEINS task 1.4.3).

3. Collect water samples for the determination of pCO2, total carbonate, oxygen, nutrients and the sulfur hexafluoride (SF6) tracer, as part of the ESOP-2 program.

4. Collect water samples for determination of total carbonate, oxygen and nutrients as part of the ESOP-2 program. These samples are for time series which are intended to show variability with time and carbon-nutrient relationships.

5. Collect continuous surface data on temperature, salinity and pCO2, for the ESOP-2 program to complement data from the occupied stations.

6. Capelin survey around Iceland.

CRUISE NARRATIVE

The RV Bjarni Sæmundsson left Reykjavík harbor at 2000 hours on the 4th of November 1998 for the B12-98 cruise.

The vessel headed for the Faxaflói section ( Figure 1) occupying the first eighteen stations. From there the ship headed for the Denmark Strait NW of Iceland (Látrabjarg and Kögur sections) from the Icelandic coast to the ice-limit and eastwards into North Icelandic waters (Húnaflói, Siglunes, Slétta, and Langanes NE sections). After occupying North Icelandic waters the vessel continued eastwards into East Icelandic waters (Langanes E and Krossanes sections) and to South Icelandic waters (Stokksnes and Selvogsbanki sections). The RV arrived to Reykjavik at 1000 hour on the 1st of December.

Sections confined to VEINS are those of Faxaflói, Látrabjarg, Kögur, Langanes NE and Krossanes. Locations of hydrographic sections and CTD stations are shown in Figure 1 as well as location of the current meter mooring in VEINS 1.4.3 (KR4, indicated by m).

HYDROGRAPHY

The hydrographic work was carried out with a CTD-water sampling units equipped with Seabird Inc. SBE 911plus CTD's. The unit, a MRI made rosette equipped with 12 modified Hydro-Bios 1.7 liter water bottles and a General Oceanics underwater unit, was used on all CTD stations. The CTD was equipped with newly calibrated temperature and conductivity sensors and water samples were collected at deepest sampling level on all stations for calibration purposes.

CTD (SBE 911plus CTD System) Sensor Status.

	    Temp. Calibr.  Cond. Calibr.
	   sensor date    sensor date

Unit A       1428 15-10-98  1162 15-10-98

CHEMISTRY

Samples for oxygen measurements were collected in 60 ml bottles, and Winkler reagents added. Samples were then placed in a dark cold storage until the time of analysis. Oxygen concentration was determined using a modified Winkler method.
Samples for nutrient analysis, nitrate, phosphate and silicate, were collected on selected stations, in 250 ml polyethylene bottles. Samples were freezed, for later analysis in land on a ChemLab auto-analyzer.
Samples for pCO2 and total carbonate were collected on 3 stations in 500 and 250 ml bottles, preserved with mercury chloride and placed in cold storage.
Samples for sulfur-hexafluoride (SF6) were collected at 3 stations in 500 ml bottles supplied by the University of East Anglia and placed in cold storage.

MOORINGS

During the B12-98 cruise the following current meter mooring was serviced and deployed (VEINS tasks 1.4.3).

St.id.	     Position       Water Instr. Type           Serial  Date    Notes
	Lat.	  Lon.	    depth depth			no.
KR-4	65 00.00N 11 17.00W  525    80	 Aanderaa RCM7	12311	261198	recovery failed
KR-4	65 00.00N 11 17.00W  525   300	 Aanderaa RCM7	12312	261198	recovery failed
KR-4	65 00.00N 11 17.00W  525   475	 Aanderaa RCM7	12314	261198	recovery failed
KR-4	65 08.60N 11 11.07W  626   150	 Aanderaa RCM7	12308	261198	deployed
KR-4	65 08.60N 11 11.07W  626   265	 Aanderaa RCM7	00172	261198	deployed

RESULTS

All of the goals of the cruise were achieved (see list of stations and cruise track-Figure 1). One current meter mooring east of Iceland (KR4) which had earlier failed in recovery was deployed again in a nearby location (65 08.00N; 11 10.11W).

The main results of the hydrographic conditions in Icelandic waters in November 1998 were the following:

The Atlantic Water (the Irminger Current) south and west of Iceland showed as since 1997 high temperatures (7-9°C) and salinities (>35.15). In the Denmark Strait area (Látrabjarg section) the Atlantic Water had even an unusual extent across the Greenland-Iceland Channel into the East-Greenland shelf (Dohrn Bank). The inflow of the Atlantic Water into North Icelandic waters was on the other hand hampered by an intrusion of relatively cold (0-3°C) and low-saline waters from the north. Farther east in North Icelandic waters and east of Iceland temperature and salinity was moderate or about normal (4°C, 34.7). The cold tongue of the East Icelandic Current northeast of Iceland was also relatively far off with temperature above 0°C but again with rather low salinity (<34.7).

The overall results of interest for the VEINS project are a pronounced flow of warm and saline Atlantic Water south and west of Iceland with relatively wide extension to the west, whereas this flow did not reach North Icelandic waters where cold and low saline waters from the north were dominating. Towards east in North Icelandic waters the hydrographic conditions were moderate in temperature and salinity and the East Icelandic Current was relatively far off with temperatures above 0°C but low salinity (<34.7). As usual the cold "overflow" along the East Greenland continental slope (Figure 3a ) showed potential temperatures of 1-2°C on the Faxaflói section.

Preliminary TS-diagrams from the Faxaflói , Látrabjarg , Kögur , Siglunes , Langanes NE , Langanes E , Krossanes , Stokksnes and Selvogsbanki sections show the results above. In addition are preliminary potential temperature and salinity sections shown for Faxaflói (Fig. 3a and Fig. 3b), Látrabjarg (Fig. 4a and Fig. 4b), Kögur (Fig. 5a and Fig. 5b), Siglunes (Fig. 6a and Fig. 6b), Slétta (Fig. 7a and Fig. 7b), Langanes NE (Fig. 8a and Fig. 8b), Langanes E (Fig. 9a and Fig. 9b), Krossanes (Fig. 10a and Fig. 10b), Stokksnes (Fig. 11a and Fig. 11b) and Selvogsbanki (Fig. 12a and Fig. 12b) sections respectively, of which Figures 3, 4, 5, 8 and 10 are part of the VEINS programme.

Another potential temperature and salinity sections have been included in this report showing the Mooring Section IS8 (Fig. 13a and Fig. 13b). For location of the above sections see Figure 1 and the station numbers.

CONTACT

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