Departure: Reykjavík, Iceland, May 15th 2000
Arrival: Reykjavík, Iceland, June 1st 2000
Ástþór Gíslason, Chief scientist
John Mortensen, Physical oceanography
Magnús Danielsen, Physical oceanography
Jóhannes Briem, Moorings
Kristinn Guðmundsson, Phytoplankton
Kristín Valsdóttir, Phytoplankton
Jón Ólafsson , Chemical oceanography
Sólveig R. Ólafsdóttir, Chemical oceanography
Hildur Pétursdóttir, Zooplankton
Sara Smolenack, Zooplankton, University of New Hampshire, USA
Ann Buckley, Zooplankton, University of New Hampshire, USA
Steven Manganini, Sediment trap, Woods Hole Inst., USA
The B06-2000 cruise was carried out by the Marine Research Institute (MRI) on the RV Bjarni Sæmundsson with the following aims:
The RV Bjarni Sæmundsson left Reykjavík harbor at 2000 hours on May 15th 2000 for the B06-00 cruise.
The vessel headed for the Faxaflói section ( Figure 1) towards East Greenland, from there to the Látrabjarg and Kögur sections in the Denmark Strait, where sea-ice conditions hampered the work and not all the standard stations could be reached as planned. The vessel then headed eastwards into North Icelandic waters to the Hornbanki, Húnaflói, Siglunes, Slétta, Langanes NE and Langanes E sections, during which a mooring in the northern part of the Iceland Sea was recovered. From there the vessel headed for the Krossanes, Stokksnes, Ingólfhöfði, Háfadjúp and Selvogsbanki sections and arrived to Reykjavik at 1400 hours on June the 1st 2000 after having sailed 3141 nm. During the cruise exceptional good weather was experienced so no time consuming stops were needed and call of ports were limited to the planned two stops (Husavík and Eskifjörður) for scientific crew exchanges. Late in the cruise the vessel was called to Þorlákshöfn for a very short stop during which scientific equipment was brought on board.
The hydrographic work was carried out with two independent CTD-water sampling units both equipped with the same 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 combine with a Sea-Tec fluorometer and a transmissometer, 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 mainly used on few special stations in relation to chemical sampling. Both units made use of the same pair of newly calibrated temperature and conductivity sensors and water samples were collected at deepest sampling level on all stations for calibration purposes.
Temp. Calibr Cond. Calibr. sensor date sensor date Unit A 868 29-01-00 549 01-02-00 Unit B 868 29-01-00 549 01-02-00
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
all standard stations, in 250 ml polyethylene bottles and analysis at sea 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 oxygen-18 were collected at 1 stations as full profile.
All of the goals of the cruise were achieved (see list of stations and cruise track-Figure 1).
The main results of the hydrographic conditions in Icelandic waters in May 2000 were the following (see e.g. T - 50m , S - 50m , T - 100m , S - 100m , and T - botm ):
Atlantic Water south and west of Iceland showed relatively high temperatures (6-8°C) and salinities (35.00-35.24). The high salinities still being in accordance with those observed since 1997, which were higher than during the years before or even since the sixties and seventies. However, there were during the cruise observed a slight decrease in both temperature and salinity towards the west in the Atlantic Water mass compared with the three previous years. Temperatures of 4-6.5°C and salinities above 35.00 were observed in the Denmark Strait area off the NW peninsula and drift-ice was observed in the deeper parts of the Strait. The inflow of Atlantic Water into North Icelandic waters was this spring also very pronounced reaching the area east of Siglunes (3-4.5°C, S>34.95), and it even reached values as high as 34.85 in salinity off Langanes E. Compared with May 1999, May 2000 showed up with a larger northward and eastward extent of the Atlantic water mass domain than the previous year, even though the inner stations on the Siglunes section were somewhat colder and less saline whereas the outer stations were warmer than in 1999. Also this year no cold and low saline water in the surface layer was observed, although a relatively weak halocline was observed over the inflowing Atlantic Water core. Thus the cold waters from the north were found far off and characterized by unusually high salinities above 34.75. Drift-ice was observed north of 68°N on the Siglunes section. Off the East coast temperature and salinity were 1-3.5°C and above 34.75 respectively, and the cold East Icelandic Current was far-off and "very" moderate in its characteristics (>0-1°C and almost 34.8). The relative high values in the East Icelandic Current are in accordance with observations observed since August 1999, which have showed an increasing trend in both temperature and salinity. Atlantic conditions from the south found at the shelf break on the Krossanes section were this year very pronounced (t>7.5°C, S~35.23).
Summarized:
Faxaflói is observed to be colder and less saline than the three previous years, but compared with the last decades the properties of the Atlantic Water are still above average.
North of Iceland: the Atlantic inflow to north Icelandic water is in progress, the properties of the inflow are not as high as observed in during spring 1999, however the Atlantic influential domain was more wide-spread.
Properties of the East Icelandic Current were observed to be higher than for many years (1984 and before 1963) i.e. above 0°C and almost 34.8 in salinity.
East of Iceland: relative warm and saline.
South and southwest of Iceland: a little colder and less saline than 1999 but still relatively high values.
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), Hornbanki (Fig. 6a and Fig. 6b), Siglunes (Fig. 7a and Fig. 7b), Slétta (Fig. 8a and Fig. 8b), Langanes NE (Fig. 9a and Fig. 9b), Langanes E (Fig. 10a and Fig. 10b), Krossanes (Fig. 11a and Fig. 11b), Stokksnes (Fig. 12a and Fig. 12b) and Selvogsbanki (Fig. 13a and Fig. 13b) sections respectively.
For location of the above sections see Figure 1 and the station numbers.
In case of further information contact:
| Héðinn Valdimarsson | Email: | hv@hafro.is |
| John Mortensen | Email: | johnm@hafro.is |
| Svend-Aage Malmberg | Email: | svam@hafro.is |
| Jóhannes Briem | Email: | briem@hafro.is |
or by mail:
Att. nameor
Tel. (+354) 55 20240
Fax. (+354) 56 23790
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| Responsible: John Mortensen | MRI | ||
