Scientific and Environmental Remotely operated vehicle (ROV) Partnership using Existing iNdustrial Technology (SERPENT) ran a highly successful mission including 7 days of ROV operations. Eight video transects were completed, for megafaunal abundance, diversity and distribution in the area. Transects were conducted every 450 metres and extend to 100m from the drill site. Videos will be analysed for megafaunal diversity and habitat mapping during 2006.
There is only one habitat type at ENC03, soft bottom. There is no evidence of any rock formations or hard bottom of any type. ENC02 was approximately 30m away from ENC03 so there was some overlap in drill spoil. This will be accounted for when analysing video transects. Preliminary analysis indicates a high density and diversity of megafauna. The main component of the megafaunal community is consistent with soft bottom communities and includes echinoderms (asteroids, echinoids) a host of crustaceans (prawns and large isopods), eels that live in the sediment and some bottom dwelling fish. At approximately 85m along each transect, sponge beds were evident. Further investigation on subsequent missions will identify the extent of these beds.
A variety of prawns, crabs, eels, amphipods, isopods and fish were attracted to the bait traps. Initial examination of the data suggests that there is a difference in the diversity of organisms that visit the traps (inside vs outside the drill spoil). Isopods, shrimp and eels only appeared to visit traps outside of the drill spoil. Further analysis will validate any trends in the data.
Species collected for determining the level of heat shock protein expression:
* 8 isopods kept alive in seawater once brought to the surface
* 4 isopods exposed to drill mud once brought to the surface
* 4 isopods exposed to copper sulphate once brought to the surface
* 1 hag fish outside of the drill spoil
* 3 isopods outside of the drill spoil
* Numerous small (<1cm) amphipods from both within and outside of drill spoil.
Statement: Baited traps were deployed both within and outside of the drill spoil to attract mobile megafauna. Traps were examined every 24 hrs and video taped for 5 minutes. Isopods and amphipods from within the spoil (10m from Blow-Out converter BOP) and outside of the spoil (100 m from BOP) were collected for heat shock protein analysis. In a second experiment, isopods outside of the spoil (100m from BOP) were collected and exposed to drill mud (n=4), copper sulfate (a known inducer of heat shock proteins n=4), and sea water as a control (n=4) once brought to the surface. Traps were re-deployed every 24 hrs and collection repeated.
Woodside Energy Ltd
Katie Robertson, The University of Sydney (USYD)
The science goals for this project are to expand on baseline environmental surveys carried out in the area on behalf of Woodside. We will conduct detailed ROV megafaunal video surveys to provide quantitative data on megafaunal ecology; particularly abundance, diversity and distribution in this area. In addition we will conduct a series of experiments to quantify the expression of heat shock proteins on deep sea organisms from within and outside of drill spoil. One set of experiments will be an in situ deployment and another set will be completed at the surface to determine the effects of drilling mud on heat shock protein expression.