Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

Immediate Report of Victoria University Of Wellington Antarctic Expedition 1987-88: VUWAE 32

Sea floor sediment sampling

page 5

Sea floor sediment sampling

At each of the eight sampling transects, a bathymetric survey was carried out to determine the slope and topography of the sea floor (Figure 2). This was carried out by drilling 4-inch holes in the sea ice and using an echo sounder to measure the water depth by passing the 200 kHz transducer through the hole below the sea ice.

The sampling strategy was designed so that sediment was recovered from similar depths at each transect. The depth zones sampled included a sea ice scoured zone, from 0 to 5-10 m, a possible wave influenced zone, from 5 to 20 m, and a non-wave influenced zone, from 20 to 100 m. The effects of bottom currents, which are depth and site specific, were also considered in the sampling strategy.

The sediment samples were recovered with a modified Shipek grab designed and built at Victoria University. The grab has two interchangeable 180×180 mm hemicylindrical buckets that take a 90 mm deep scoop of the sea floor. These samples were first photographed and described intact, then split into portions and preserved in formalyn. A subsample of each grab will be preserved as an archive specimen, and another split will be used for foraminiferal work and grain size analysis.