Submitted February 24:

After losing 24 hours research time to rough weather, the last four days have been spent completing core station transects from the edge of the Ross Ice Shelf, and down the continental slope. These are the stations where all our sampling equipment is deployed.


Photo: The midday to midnight watch gathered proudly around their erratic. By J. Mitchell

The DTIS (Deep Towed Imaging System) video and still images have shown us that much of this area of seabed west of Iselin Bank, adjacent to Cape Adare, is very rocky compared to the southern shelf areas sampled earlier in the voyage. The seabed is covered with rocks ranging in size from a couple of centimetres up to a metre or more across. Unlike most of the world’s seabed, the rocks we are seeing were not formed in situ but have been ice rafted from the Antarctic mainland.
Photo: Seabed image showing a range of drop stones from large rocks to small pebbles. DTIS, NIWA

The numerous massive glaciers on shore pick up rocks on their slow flow to the coast from inland Antarctica. The rocks are carried on the surface or buried deep within the glacier. These rocks (known as glacial erratics) often show evidence of this movement, with smoothed faces and scratches worn deeply in their surfaces. When the glacier fronts reach the coast they break off, forming icebergs that carry their rock load with them until the bergs melt, dropping the rocks to the seafloor. Also contributing to this rock transport is the collapse of the steep cliffs onto the surrounding sea ice. The sea ice breaks up and moves offshore during the summer thaw, melts and the ‘drop stones’ fall to the seabed further offshore. Evidence of this process is seen as far north as the Chatham Rise, east of New Zealand.
Photo: Erratic in the cod end of the beam trawl. By J. Mitchell

The presence of these rocks has made it very hard to successfully collect quality biological samples and the gear regularly comes back on board in need of repair.
Photo: Beam trawl on deck with large erratic jammed in the cod end. By J. Mitchell

See the Science Report on CAML-Cousteau Expedition tracking page

From February until mid-March 2008, New Zealand scientists are embarking on an eight-week voyage to the Ross Sea to survey the marine environment and explore the variety of life forms (biodiversity) in the region. This is part of the Census of Antarctic Marine Life and scientists on board will also contribute to the NZ Science Learning Hub for teachers and students. Follow all CAML expeditions routes on the CAML-Cousteau Expedition tracking page.