Wednesday, August 4, 2010

2010 Dive Expedition to Shag Harbour Rip

The follow-up dive expedition to the 2009 dive expedition was scheduled for July 24, 2010. Its objectives were three-fold: a) re-confirm that the depressions discovered were only two of the four expected as were discovered in 2009; b) to collect measurements the depressions in detail, such as diameter, depth, distance from other depressions; c) to collect samples of the seabed bottom exterior to the depressions, a sample of the seabed within the depression, and excavate the centre of a depression and collect samples from the excavation below the surface of the bottom.

The bottom was observed to be entirely different from the previous year's dive. The observations made during the last expedition indicated that the bottom was peppered with kelp growth, and the depression was relatively easily identifiable, despite the limited visibility, due to it being devoid of plant growth, giving the impression of a "clearing in the woods". However, in this dive expedition, the bottom was rocky and pebbly, and was covered in a 2-3cm spherical sponges packed into what could be described as "broadloom" on the bottom. The characteristics of the spherical sponges were observed to be relative turgid and slippery, with their surface pocked-marked, similar to what one finds on golf balls. It was nearly impossible to stick one's finger through the spongy mass into the underlying substrate. This was considered most unusual and inconsistent with the seabed characteristics observed in the dive expedition of 2009. The dive proceeded for approximately 20-25 minutes, at which time, there was nothing found, and the dive was concluded.

For a complete report on this dive expedition, along with photos, click "Shag Harbour Rip Dive Report - July 24, 2010".