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As predicted, sampling the very rugged seabed in this canyon system at the edge of the continental shelf has been difficult. The results, however, have been well worth the effort. At the cost of some torn trawl nets, we have managed to get imagery and samples down to 1500m, with the very diverse seabed offering up a similarly diverse fauna. Last night we recorded the most fish species from any one trawl - 16 including at least one which was new to this survey. The benthic invertebrates were similarly diverse with a great range of sedentary groups, such as sponges, bryozoans (lace coral), tunicates (sea squirts), gorgonians and some very large solitary corals, forming the main supporting structure for an equally diverse variety of mobile groups such as polychaete worms, amphipod crustaceans, ophuroids (brittle stars), crinoids (feather stars), echinoids (sea urchins), asteroids (sea stars), pycnogonids (sea spiders) and a range of molluscs. Early this morning we stopped the benthic work temporarily and switched our efforts to sampling the waters around the very large ice-berg nearby, with the intention of identifying whether it is a source of trace nutrients that might stimulate plankton growth. Satellite imagery indicates the iceberg is about 35 km long by 18 km wide. If it is 400m deep, it contains 252,000,000,000,000 litres of water or 12 million litres for every one of the 21 million Australians. You would need a pool 3m deep by 40m wide by 100m long to hold your share. The berg is designated B-17A and came into this region in October 2006. It comes from a large chunk of the Ross Ice Shelf that calved between 160-165W in April 2000. This section subsequently broke up, with other fragments heading in the opposite direction. Regards, Martin and Sarah.
Map
A map showing Australia and Antarctica. The map shows the journey of one voyage that has occured in the season, with each route highlighted in a distinct colour.