Preface The expedition ARK XIX/3 with the German icebreaking RV ...

there were generally slightly higher Chl a signals detected in the BBL at the coral sites
and in downstream (southward) direction of the coral mounds. However the signals
were not strongly enhanced which lead us to conclude that the increased amount of
particulate carbon was of already inferior nutritional value. That indicates that the flux
of carbon in the BBL at the coral sites was high, but it mostly refers to less labile
refractory carbon which has already passed many resuspension loops. In order to
investigate the particles transported in the BBL, bottom water was sampled by a
multicorer and a box corer and the sediment surface was carefully resuspended in
order to sample recently settled material. The samples will be transferred to the
laboratory for the determination of settling velocities, critical shear velocities and
bioavailability.
A. 4.7 Water mass properties and intra-province variation
Unnithan, V., Dorschel, B., Thomsen, L.
The Porcupine Seabight and Rockall Trough (of which the Porcupine Bank forms an
eastern margin) are situated along on the NE Atlantic margin. The Porcupine Seabight
represents an enclosed basin in which the hydrography differs distinctively from the
Rockall Trough. The latter is closely linked to the Atlantic thermohaline circulation. The
investigated areas are separated by the Porcupine Bank over which water shallows to
less than 300m.
On the basis of earlier investigations (White, 2001, New, 2001), the deeper water
masses in the Rockall Trough and Porcupine Seabight are broadly sub-divided into:
1) The ENAW that originates in the Bay of Biscay and is composed of mixed water
masses and extends down to 750m from the surface waters.
2) The MOW flows out of the Strait of Gibraltar and one arm flows northward along the
eastern margin of the Atlantic. This water mass occupies the intermediate waters
and is characterised by high salinity, low oxygen core and higher temperatures (?)
3) The Labrador Sea water is a cold, low salinity, high oxygen water masses occupies
the intermediate to deep parts of the water column.
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