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EUROFLEETS2 Funded Project "PREPARED" Results

Present and past flow regime on contourite drifts west of Spitsbergen: Preliminary results from the EUROFLEETS2 PREPARED cruise
(RV G.O. Sars, expedition 191)

 

 

Project Acronym &Title: PREPARED - Present and past flow regime on contourite drifts west of Spitsbergen

Area: Norwegian Sea to west of Svalbard

Research Vessel: RV G. O. Sars, IMR and UiB, Bergen

Chief scientist: R.G. Lucchi and V. Kovacevic, OGS (Istituto di Oceanografia e di Geofisica Sperimentale), Sgonico (TS), Italy

Other Project Partners: University of Gothenburg (UNIGOT), Sweeden
Institute of Oceanology Polish Academy of Sciences (IOPAS), Poland
University of Tromsø (UiT), Norway
National Research Council (CNR-ISMAR), Italy
University Centre in Svalbard (UNIS), Norway
University of Bergen (UiB), Norway
University of Bremen, Germany
Alfred Wegener Institute for Polar and Marine Research (AWI), Germany

Date: 5th -15th June 2014

RV G. O. Sars

Cruise map

   

Lucchi R.G., Kovacevic V., Caburlotto A., Celussi M., Cosoli S., Deponte D., Ingrosso G., Mansutti P., Relitti F., Tirelli V. (OGS, Italy); Aliani S., Corgnati L., Langone L. (CNR-ISMAR, Italy); Ersdal E.A., Skogseth R. (UNIS, Norway); Fredriksson S., Robijn A., (UNIGOT, Sweden); Goszczko I., Lacka M. (IOPAS, Poland); Husum K, Laberg J.S. (UiT, Norway); Mezgec K. (University of Siena, Italy); Morigi C. (University of Pisa, Italy-GEUS, Denmark); Ponomarenko E. (University of St. Petersburg, Russia/AWI, Germany); Realdon G. (University of Camerino, Italy, and EGU-GIFT program Teacher at Sea).

Good weather, calm sea conditions, and the enthusiastic, collaborative participation of the scientific party and crew of the RV G.O. Sars expedition 191, allowed fulfilling the dense cruise program of the EUROFLEETS2 PREPARED project. The obtained highly valuable dataset will permit a very-high resolution climatic and oceanographic reconstruction of the past 20 ka along the western side of the Fram Strait (Greenland Sea, Arctic).

PREPARED scientific team

 

Main Objectives

 

The aim of the project PREPARED is to investigate and define the present and past oceanographic conditions around two contourite drifts located on the eastern side of the Fram Strait (Bellsund and Isfjorden sediment drifts) using a full range of measurement time scales, from instantaneous (CTD) and seasonal (moorings) oceanographic measurements, to the recent (Box corer) and geologic (Calypso core) past record. The project is therefore conceived under a multidisciplinary and interdisciplinary view in order to consider the interaction between various components of the Arctic system in this area. Our study area is regarded as a key zone for the reconstruction of the Arctic Ocean circulation, which in turn, plays a key role in the global thermohaline system.

Working area and track chart of the R/V G.O. SARS Cruise 191, Eurofleets-2 PREPARED. Red solid lines indicate the outward track whereas dashed lines refer to return trip.

 

Work progress and main achievements

The PREPARED data set was acquired during the Eurofleets-2 cruise conducted on board the Norwegian RV G.O. Sars for the period of June 5-15, 2014. The newly acquired dataset includes about 2780 km of underway measurements (hull-mounted Acoustic Doppler Current Profiler and thermosalinograph); 60 Conducivity-Temperature-Depth (CTD) casts along 5 main transects; 22 sites for water sampling at different depths for biogeochemical characterization of water masses; 13 meso-zooplankton samplings carried out by vertical hauls (WP2 net) and 20 by horizontal hauls (Manta net) for the study of the present biological productivity of the area; about 120 km of site survey including high- resolution multibeam lines and sub-bottom profiles for the identification of surface and shallow current-related structures; 5 Box cores; and 2 Calypso piston cores 19.67 and 17.37 m long with an excellent sediment recovery up to 92%. In addition, 3 moorings were deployed for seasonal measurements of water currents direction and velocity, water mass temperature and salinity, and to determine the annual amount of local sediment input.

Preliminary onboard analyses outlined the presence of different water masses occupying different portions of the water column. Cold, oxygenated and low salinity water mass moves in the deep northern part of the Storfjorden Trough under the effect of the Coriolis force and tide configuration considerably affecting the velocity and bottom distribution of the cold water mass. Warmer water generally occupies the upper layer up to ~500 m depth at the shelf break outside Hornsund and the whole water column at the shelf. Part of the shelf is occupied by low salinity, oxygen rich Surface Water (SW) and by colder, less saline Modified Atlantic Water (MAW). The contrast with AW following the shelf slope and shelf break creates a density front in the area.
In the northern end of the Strofjorden Trough, box cores revealed the presence of benthic foraminiferal microfauna adapted to the presence of sustained bottom currents (large agglutinated, uniserial species like Hyperammina subnodosa and Reophax spp), supporting the oceanographic evidences.
Preliminary micropaleontological analyses on the long Calypso cores indicate the recovery of the past 20 ka record with an expanded Holocene sequence, over 5 m-thick, that will allow us to obtain very-high resolution palaeoceanographic and palaeoenvironmental reconstructions at centennial and possibly decennial resolution.

The oceanographic, geological, and biological data collected during the cruise are presently under process. A post- cruise meeting will be held in Trieste during January 2015 for preliminary analyses presentation, definition of the new research deadlines, paper submission and congress presentations.

For more information:

The PREPARED cruise included, for the first time within a Eurofleet cruise, a high-school teacher assigned to PREPARED by the EGU Committee on Education through the Geosciences Information for Teachers (GIFT) program
(http://www.egu.eu/education/gift/). The teacher was involved during the on board research activities and produced a blog for dissemination (http://tasprepared.blogspot.it/). Here experience will be presented at educational congresses including next EGU-GIFT meeting in Vienna 2015