Three ice cores were drilled in sea ice (2.1 m thick) in the region of Gondwana Station in Terra Nova Bay during the 06-07 season. The cores were stored in black plastic bags and then replaced back within the same hole but in reverse order so that the algae from the bottom of the ice were now at the surface of the ice and the ice at the ice surface were now at the ice water interface at the bottom ... of the sea ice. An additional three profile cores were also drilled but were replaced back into their original holes in the normal configuration as a control. A further 3 cores were then extracted from the ice and processed for chlorophyll, cell numbers and species composition etc as above. At the end of the deployment period the six cores still in the ice were redrilled and extracted from the ice and samples also taken for chlorophyll, cell numbers and species composition as above. A further 3 cores of undisturbed ice were also taken.