Aquatic Robot Sirius audits the health of Ningaloo Reef | Innovations

Aquatic Robot Sirius audits the health of Ningaloo Reef

Aquatic Robot Sirius audits the health of Ningaloo Reef

Updated 10 April 2012, 9:30 AEST

How do you keep up-to-date with a seabed and in particular the Ningaloo Reef, a heritage-listed site off Australia's west coast?

Answer:  You call on Sirius - again.

 

DESLEY BLANCH:   Sirius is an aquatic robot developed by University of Sydney ‘mechatronic’ experts and five years on scientists have returned to Ningaloo Reef to plunge its watery depths to review its changes.

Sirius can dive to depths of 800 metres and take up to 50,000 images in a day with its high resolution cameras. It will also collect detailed multi-beam sonar and water-column measurements while underway.

The data collected will provide scientists with unparalleled information on how deep-sea communities may have been distributed, damaged or altered over time.

Project leader is Associate Professor Stefan Williams from the Australian Centre for Field Robotics at the University of Sydney. Stefan’s team are now on a boat over the Ningaloo Reef and several days into their survey, having just retrieved Sirius from a dive.

ASSOCIATE PROFESSOR STEFAN WILLIAMS : The weather plays a large part for the comfort of the crew more so than the robot. The weather out here has been phenomenal; it’s like a mill pond, there’s no swell and very little wind. It’s hot, kind of dealing with 38 degree air temperature and the water temperature is up around just under 30 degrees as well, so it’s pretty warm, but conditions are really ideal for doing this kind of work.

DESLEY BLANCH : It’s sounds perfect. Well, how does today’s Sirius compare with that first vehicle five years ago? I mean you’d hope it was smart enough to return to the exact same spot where it captured images the first time, yes?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : Yeah, there’s been a few changes to the vehicle over the intervening years. We’ve refined a lot of the algorithms we use for navigation, so, for helping the robot figure out where it is, the way in which we process and collect the imagery has changed a little bit as well. But materially, we’re collecting the same sort of data which then would allow us to compare what we’re seeing now with what we collected five years ago.

DESLEY BLANCH : And what’s the range of technologies that Sirius carries to give you these results that you want?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : We carry a number of different sensors on the vehicle, so there’s a comprehensive suite of navigation sensors which are used to measure things like depth and velocity over ground heading and we use all that information along with acoustic systems on the ship to allow the vehicle to know where it is in space, so it can accomplish the missions we’ve programmed it with. It also carries high resolution stereo cameras which take images of the sea floor, multi-beam sonar and measurements of water column, like conductivity, temperature, depth. We have fluorometers which measure chlorophyll and other properties of the water column.

DESLEY BLANCH : And how much terrain can the vehicle cover in a single day?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : We’re typically running transect lines on the order of six kilometres in length for a single dive and we’ll do up to three of those in a day. So we’ll either have these long transects that go from relatively shallow water across the shelf down over the continental slope and then we’re also running missions which consist of both broad and dense grids, which target particular features on the sea floor and these are being used to establish reference sites which we’ll be able to revisit over time.

DESLEY BLANCH : That’s a big larger an area than an underwater diver could do I imagine!

ASSOCIATE PROFESSOR STEFAN WILLIAMS : Yes, and it’s in depths beyond which you could actually have divers surveying. So divers are fairly effective down to 20 or 30 metres. Our dives are typically starting around 20 to 30 metres and then heading out to: we’ve just had the vehicle down to 150 metres and we’d set it to cut off at that depth and it’s said: Yep, I’ve got there - and come up, so we’ve just collected it.

DESLEY BLANCH : And you’ve automated Sirius to the extent it can quickly match up images from those first surveys and in fact it can group these 3D images into categories of interest for other marine scientists. So what are some of those categories, I guess one would have to be coral.

ASSOCIATE PROFESSOR STEFAN WILLIAMS : Yeah, a lot of our research work is in how we, not just collect this kind of data using these aquatic systems but how we interpret the data and provide that to scientists, help them understand what’s on the sea floor, so we do have techniques for matching images. This gets a little bit tricky over long periods between these dives, because things have changed quite substantially, but we’re also developing techniques in collaboration with some of my research fellow colleagues and PhD students to automatically look for patterns in the data and identify particular organisms so we can quickly group up the data and say Okay, these are examples of things that look similar and those often have a sort of an ecological interpretation, although in the work that we’re doing at the moment, the algorithms don’t really understand what they’re looking at. They’re just looking for similarity in sets of images.

DESLEY BLANCH :  Those images I imagine though could be algae and kelp and things like that?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : Well, up here on the North West Shelf, what we’re seeing is a lot of coral in the shallower waters and then out into deeper waters, we’re coming across fairly dense sponge communities and the scientific partners from AIMS (Australian Institute of Marine Science) who we’re working with, are interested in how those different habitats correlate with the multi-beam models of the sea floor that they have, so they’re trying to understand the relationship of where these communities, those sponge and corals relate to depth and bottom hardness and things like that.

DESLEY BLANCH : And I guess helping to predict future changes for the area?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : Yeah, so there’s a big interest in seeing what changes in oceanographic conditions, whether it’s temperature or acidification of the oceans, what impact those will have on these sorts of communities.

DESLEY BLANCH : And Stefan, using Sirius, have you discovered or photographed much that is new to science?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : Yeah, one of the PIs [principal investigators] that we’re working with was suggesting that there’s a good chance that a lot of the sponges that we’re seeing have not been described. There is not a lot of work that’s collected this sort of imagery in this region and Ningaloo is a World Heritage site for a reason. There are a number of state and national marine parks around that are designed to protect these areas and I guess part of the objective of this trip is to document what’s here and to understand how the marine park zoning relates to what’s actually on the sea floor.

DESLEY BLANCH : There are also Australian scientists who are currently mapping the Great Barrier Reef and they’re modelling their findings on the Google Street View to spotlight the impact of climate change. How similar is their technology to yours?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : In terms of collecting marine imagery, it’s really similar. They are using divers or predominantly planning to use divers with scooter-based systems that have a couple of cameras on them, so you’ll be able to have the familiar Google Street View, kind of panoramic view of the scene. The data we collect is typically collected by an autonomous underwater vehicle flying at a fixed height above the sea floor, so we’re looking down on the sponges or the coral. The stereo allows us to generate 3 Dimensional models of that surface, which our partners can then use to sort of fly around virtually in the scene. So there are quite a bit of similarities between the two and in fact, that group have approached us to be involved in the modelling of the GBR [Great Barrier Reef].

DESLEY BLANCH : Well Sirius has been used around the Australian coastline, but where else has it been operating?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : Actually Sirius has been limited really to Australian waters, so we’re part of a national integrated marine observing system program which is documenting marine habitat sites around the country, so we’ve worked in W.A. from as far north as Scott Reef, down to Rottnest [island];  to around on the east coast from Tasmania, up through New South Wales and into Queensland, so that’s where Sirius has done most of its work.

We’ve been using similar sorts of technologies overseas, so one of my colleagues has led trips to Greece collecting this sort of data. We have a number of different camera systems based on the ones that are on the UV [Sirius], which have been deployed on the West Coast of the US, in Switzerland and through the Mediterranean actually. We’ve also worked with colleagues from the University of Rhode Island.

There’s a lot of interest, not only from a biological perspective, but also all from marine archaeology in terms of collecting these kind of imagery, building these detailed sea bed models that we’re doing.

DESLEY BLANCH : You mean like submerged cities or old shipwrecks or something like that?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : Exactly, so the work we did in Greece last year, involved both diver-held systems. A diver would swim out with the stereo imaging system to document particular areas in a Neolithic settlement site, a 3500-year-old city which is now submerged between two and four metres of water. We used an AUV as well to swim over their whole site, to document this whole city and then some of the work in the Mediterranean was in deeper waters using remotely operated vehicles, stereo- imagery and some of our software to build models of wrecks on the sea floor. We’re certainly getting a lot of interest in the work we’re doing.

DESLEY BLANCH : So are you expecting severe differences in some of these photos that you’re taking for this trip?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : It’s been hard to tell. From what I understand there’s been quite a marked warming in the waters along the West Coast. We did some surveys last year south of here, at a place called the Abrolhos Islands, where we saw some fairly significant evidence of coral bleaching, which seemed to correlate with a rise in sea temperature.

Certainly I don’t understand the relationship these sponge communities might have with increased temperature and I think this is one of the things that our scientific partners are interested in finding out.

DESLEY BLANCH : And so what’s the next job for Sirius after this one?

ASSOCIATE PROFESSOR STEFAN WILLIAMS : (laughs) Ah, we’re scheduled to go back to W.A.[Western Australia] along Rottnest [island] and up towards the Abrolhos [islands] in April and then off to Tasmania in June and we may have an overseas trip to Italy with Sirius towards the middle of the year still to be confirmed.

DESLEY BLANCH:  Have robot will travel. Stefan Williams is Associate Professor at the Australian Centre for Field Robotics at the University of Sydney.  We spoke to him on board a ship off the north west coast of Australia and over the heritage-listed site of the Ningaloo Reef.

Contributors

Stefan Williams

Guest

 

Australian Centre for Field Robotics

The University of Sydney

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