HAFRANNSÓKNASTOFNUNIN

Marine Research Institute

Reykjavík, Iceland

VEINS@ICES HAFRÓ MAIN










CRUISE REPORT

CRUISE NUMBER: B13 - 99
(September 1999)


















SCIENTIFIC OBJECTIVES

The B13-99 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 Denmark Strait. The investigations 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 modelling 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. Measuring the Denmark Strait Overflow. (Task 1.4.1)
    2. Determining the water mass properties of the Denmark Strait Overflow. (Task 1.4.2)
    3. Improving estimation of the freshwater flux to the North Atlantic via the East Greenland Current. (Task 1.4.3)
    4. Measuring the inflow of Atlantic Water to the Iceland Sea. (Task 1.4.4)

  2. Recover and redeploy an ADCP mooring on the Látrabjarg section in the Denmark Strait (DS1, VEINS task 1.4.1). Recover three RCM7 current meter moorings NW of Iceland in the East Greenland Current (IS6, IS9 and IS7, VEINS task 1.4.3) and redeploy the IS7 RCM7 current meter mooring. Service the IS8 RCM7 current meter mooring on the shelf east of Kögur section (VEINS task 1.4.4) and deploy two RCM7 current meter moorings (H1 and H3) complementing the IS8 mooring in measuring the Atlantic inflow to North Icelandic waters.

  3. Deploy two ADCP moorings and a thermistor chain for the "Institut für Meereskunde", Univ. of Kiel, in the vicinity of the Denmark Strait sill.

  4. Collect continuous underway measurements of surface temperature and salinity.

  5. Collect water samples for the determination of pCO2, total carbonate, oxygen, nutrients, C-13 and O-18.

  6. Collect samples for analysis of Cesium-137 and Technetium-99 (Icelandic Radiation Protection Institute and Risø National Laboratory, Denmark).


CRUISE NARRATIVE

The RV Bjarni Sæmundsson left Reykjavík harbor at 2000 hours on September 20th 1999 for the B13-99 cruise.

The vessel headed for station 9 on the Faxaflói section and continued to the Látrabjarg section in the Denmark Strait where the first nine stations on the Icelandic side were occupied. The VEINS DS1 ADCP mooring was then successfully recovered and two ADCP moorings from the "Institut für Meereskunde", Univ. of Kiel, were deploy in the vicinity of the sill in the Denmark Strait. The ship then headed for the current meter mooring site IS6 on the Greenland side of the Kögur section. Along with the CTD-station work on the section VEINS moorings IS6 and IS7 were recovered routinely and attempts to recover VEINS mooring IS9 failed due to instrumental failure in the releaser. Dragging attempts were postponed for a later cruise due to limited ship time. After redeploying mooring IS7 and occupying a few more CTD-stations on the Kögur section the ship headed for the Hornbanki section. Here the VEINS mooring IS8 was successfully serviced and two additional moorings (H1 and H3) were deployed along with the CTD station work. The vessel then again headed for the Kögur section occupying the last three station of the section. The ship then called port at Isafjördur to set a scientist ashore. Meanwhile a low pressure system was passing the area delaying the departure by 10 hours on September 26th. At first chance the ship headed for a position where a thermistor chain from the "Institut für Meereskunde", Univ. of Kiel, was deployed and continued strait to mooring site DS1 on the Látrabjarg section where an ADCP was successfully redeployed. After occupying the remaining part of the Látrabjarg section towards Greenland the ship headed towards Reykjavík arriving at 1600 on September 29th 1999.

Both sections occupied in the Denmark Strait during the cruise are part of the VEINS programme. Locations of the sections are shown in Figure 1.

HYDROGRAPHY

The hydrographic work was carried out with two independent CTD-water sampling units both equipped with Seabird Inc. SBE 911plus CTD´s. The first unit, a MRI made rosette equipped with 12 modified Hydro-Bios 1.7 liter water bottles and a General Oceanics underwater unit, was used for all standard CTD stations. The second unit (referred to as UNIT B), a SBE 32 rosette equipped with 12 Ocean Test Equipment Inc. 10 liter water samplers, was used for chemical sampling. Both units were 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       2021 17-02-99  1643 19-02-99
Unit B        868 20-07-99   549 20-07-99

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 frozen, for later analysis in land on a ChemLab auto-analyzer.
Samples for pCO2 and total carbonate were collected on 4 stations in 500 and 250 ml bottles, preserved with mercury chloride and placed in cold storage.
Samples for delta carbon-13 were collected at 3 sites as full profiles. The samples were preserved with mercury chloride.
Samples for oxygen-18 were collected at 3 sites as full profiles.

MOORINGS

During the B13-99 cruise the following VEINS moorings were recovered and deployed (VEINS task 1.4.1, 1.4.3 and 1.4.4).

St. id.		Position    Water Instr. Type           Serial	Date	Notes
	Lat.	  Lon.	    depth depth			   no.
DS-1	66 04.87N 27 04.39W   650   643	 ADCP 75 KHz   	  1287	220999	recovered
DS-1	66 04.73N 27 04.97W   648   641	 ADCP 75 KHz   	  1287	270999	deployed
IS-6	68 07.31N 25 15.67W   814    80	 Aanderaa RCM7	 12315	230999	recovered
IS-6	68 07.31N 25 15.67W   814   500	 Aanderaa RCM7	  7332	230999	recovered
IS-6	68 07.31N 25 15.67W   814   764	 Aanderaa RCM7	 12560	230999	recovered
IS-9	67 56.12N 24 40.74W  1402    80	 Aanderaa RCM7	  8743	240999	rec. failed
IS-9	67 56.12N 24 40.74W  1402   300	 Aanderaa RCM7	 12316	240999	rec. failed
IS-9	67 56.12N 24 40.74W  1402  1350	 Aanderaa RCM7	 12559	240999	rec. failed
IS-7	67 32.04N 23 44.66W   819    80	 Aanderaa RCM7	 11987	240999	recovered
IS-7	67 32.04N 23 44.66W   819   300	 Aanderaa RCM7	  9976	240999	recovered
IS-7	67 32.04N 23 44.66W   819   750	 Aanderaa RCM7	 12317	240999	recovered
IS-7	67 32.93N 23 46.24W   850    80	 Aanderaa RCM7	 10858	240999	deployed
IS-7	67 32.93N 23 46.24W   850   300	 Aanderaa RCM7	 12305	240999	deployed
IS-7	67 32.93N 23 46.24W   850   750	 Aanderaa RCM7	 12654	240999	deployed
H-3	67 08.91N 21 19.89W   235    80	 Aanderaa RCM7	 11986	250999	deployed
H-3	67 08.91N 21 19.89W   235   150	 Aanderaa RCM7	 12634	250999	deployed
IS-8	67 00.00N 21 34.00W   199    79	 Aanderaa RCM7	  8285	250999	recovered
IS-8	67 00.00N 21 34.00W   199   154	 Aanderaa RCM7	  9977	250999	recovered
H-2	67 00.11N 21 33.63W   201    80	 Aanderaa RCM7	 12314	250999	deployed
H-2	67 00.11N 21 33.63W   201   150	 Aanderaa RCM7	 12308	250999	deployed
H-1	66 53.88N 21 24.79W   140    80	 Aanderaa RCM7	 12306	250999	deployed

RESULTS

Most of the goals of the cruise were achieved (see list of stations and cruise track-Figure 1) except for the failure not recovering the one year-long current meter mooring IS9 on the Kögur section. Dragging attempts had to be postponed to another cruise due to lack of time.

Preliminary inspection of the CTD data showed still relatively high salinities and temperatures in the flow of Atlantic water on the Látrabjarg section as in September 1997 and 1998 but less so in the Kögur section. In the East Greenland Current the temperature and salinity was not as low as in September 1997 and 1998 in accordance with that no drift ice was observed in the survey area during this cruise.

Preliminary TS-diagrams from the Látrabjarg and Kögur sections show the results above. In addition are preliminary potential temperature and salinity sections shown for Látrabjarg (Fig. 3a and Fig. 3b), Kögur (Fig. 4a and Fig. 4b) and Hornbanki (Fig. 4a and Fig. 4b) sections respectively, of which the first two are part of the VEINS programme. For location of the above sections and mooring sites see Figure 1.


CONTACT

In case of further information contact:

Svend-Aage Malmberg Email: svam@hafro.is
Jóhannes Briem Email: briem@hafro.is
Héðinn Valdimarsson Email: hv@hafro.is
John Mortensen Email: johnm@hafro.is

or by mail:

Att. name
Hafrannsóknastofnunin
(Marine Research Institute)
P.O. Box 1390
Skúlagata 4
121 Reykjavík
Iceland

or

Tel. (+354) 55 20240
Fax. (+354) 56 23790




Comments and suggestions regarding this page are welcome. Please send email to johnm@hafro.is