Port Stephens Close Encounter

The AUV Sirius was surveying sites east of Broughton Island on the NSW coast near Port Stephens as part of repeat IMOS AUV surveys.  This area of the coast is well known as a Great White Shark nursery.  This video shows a snippet of video taken from a forward looking camera on the vehicle which captured a juvenile shark having a look at the vehicle.

Port Stephens Urchin Barren Survey

Andy and Stefan are in Port Stephens just north of Newcastle completing a survey just outside the mouth of Nelsons bay form Boulder Bay to Broughton Island.

Survey Area: Boulder Bay to Broughton Island

Sea urchins create urchin barren by grazing an area of all plant life. The urchins are then thought to recede due to a combination of lack of food and being eaten by predators such as grouper and snapper. It is hypothesised that if the number of the urchin predators in an area are reduced then the effects of the urchins  are amplified allowing them to become destructive to the marine environment.

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Getting Sirius ready to deploy

 

Post Tropical Cyclone Ita Diver Rig Survey

Second generation diver rig camera attached to scooter
Second generation diver rig camera attached to scooter

Andy is off the coast of Far North Queensland as far north as the Saunders Reef imaging coral reefs,  some which we had seen just before Tropical Cyclone Ita. This substantially damaged some parts of the reef and the current surveys are part of an effort to monitor its ability to recover giving us an idea of how well these delicate systems can recover from events like this.

This collaboration with The University of Queensland and the Catlin Seaview Survey was headed up from our side by Oscar and we are using the 3D rugosity techniques that were developed by Ari to analyse the small scale habitats in the reef. Rugosity is a measure of the spacial complexity of the reef and a highly rugose reef structure is important for many species of fish for hunting and refuge and is a good indication of reef health.

This is a diver based survey that uses the second generation diver rig camera that we finished developing earlier this year.  In this case it is attached to an underwater scooter that allows more ground to be covered. It is far more robust than the original diver-held stereo imaging system and has many navigation sensors and stereo cameras that allow the 3D information to be collected.

Now we are nearing the end of the trip we have collected about half a million images over more that 30 dives covering in excess of 59 linear kilometres.

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Checking the custom diver rig attachment to Catlin’s scooter
Section of Opal Reef’s 3D structure
The same section showing the images overlayed

AUV Sirius at Bateman’s Bay

The AUV Sirius has completed surveys offshore of Bateman’s Bay as part of bi-annual surveys associated with the IMOS AUV Facility program.  The surveys targeted reefs surveyed in 2010 and 2012 and will help scientists from the NSW Department of Primary Industries, the University of Sydney and the University of New South Wales in tracking changes in kelp dominated benthic habitats at these sites.

Lizard Island

Oscar, Ari, Michael and Stefan were part of a team surveying Trimodal reef at Lizard Island Research Station.  The objective was to produce a complete, 3D texture-mapped model of the reef covering approximately 5000 sq. m.  We are working with scientists from St. Andrew’s in Scotland, Macquarie University and James Cook University.  The scientists have been studying the site for in excess of 10 years.  This is the first time they will have a comprehensive map of the reef with which to study detailed coral species interactions.  We are also revisiting sites surveyed immediately following Cyclone Ita in April 2014 to assess the extent of recovery of these reefs.  Repeat surveys at sites around the island will allow scientists to investigate how different parts of the reef have recovered.

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Return to Antikythera – Highlights

The team from Antikythera put together this video highlighting the work we did with the AUV Sirius to map the wreck site.  You can see some views of the 3D map we built. The team are using this to track the location of artefacts recovered during the diving operations.

There is also a video showing some of the finds from the expedition that has been posted by the project team.  The model of the wreck site we built features in the first part of this video with an interesting transition to live footage of the ship’s anchor stock.

Return to Antikythera – Wrapping Up

After 10 days in the field, we have now packed up the AUV and associated equipment and are on our way back to Sydney.  We were able to deliver a detailed, 3D map of the wreck site generated using some 42,000 images collected by the AUV Sirius during two dives.  This model will now be used by the archaeological team to plan their excavation. Stay tuned to the project website for more details and on-going activity relating to the excavation.  We’ll feature the resulting maps once they have been published.

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Return to Antikythera – Day 9

The wind began to blow today and the forecast was for it to swing aroung the NE, impacting our ability to work on the site.  Despite our desire to get out to the site again to tackle some of our secondary targets, the decision was made to pack up our gear and focus on processing the imagery that we had collected.  The science party appear very pleased with what we have accomplished and are planning to use our site maps to help with planning of the excavation and deployment of the Exosuit next week.

Return to Antikythera – Day 8

Today we spent time on the main wreck site, re-imaging the site at a higher altitude to ensure that there are minimal holes in the final 3D models.  The site has a number of very rugose areas, including large boulders and the base of a cliff.  The vehicle completed its missions sucessfully at the main site before starting a synoptic mission over the secondary wreck site identified in 2012.  This site was very steep, with a vertical profile in excess of over 20m across the site 25m wide survey area.  The vehicle managed this terrain and completed a number of passes over the site before we brought it to the surface for recovery.